Characterization of deposited CdS thin films by Spray Pyrolysis method and used in Cd/CdS/p-Si/Al structure

NASA Astrophysics Data System (ADS)

Özakın, Oǧuzhan; Aktaş, Şeydanur; Güzeldir, Betül; Saǧlam, Mustafa

2017-04-01

In our study, as p-type crystalline Si substrate was used. Omic contact was performed by evaporating Al metal on the matt surface of crystal. On the other surface of it CdS thin film were enlarged with the technique of Spray Pyrolysis. Structural characteristics of the grown thin film was examined SEM and EDAX image. When examining SEM image of CdS thin film were totally covered the p-Si crystal surface of it was nearly homogeneous and The EDAX spectra showed that the expected different ratios metal percent exist in the alloys, approximately. On the CdS films whose surface features were investigated, at 10-7 torr pressure was obtained Cd/CdS/p-Si/Al sandwich structure by evaporating Cd. Firstly, the I-V (current-voltage) characteristics on 80K between 320K at room temperature of this structure was measured. I-V characteristics of the examined at parameters diodes calculation, Thermionic Emission, were used. The characteristic parameters such as barrier height and ideality factor of this structure have been calculated from the forward bias I-V characteristics. Consequently, it was seen that CdS thin film grown on p-Si semiconductor will be used confidently in Cd/p-Si metal-semiconductor contacts thanks to Spray Pyrolysis method.

Morphological impact of zinc oxide layers on the device performance in thin-film transistors.

PubMed

Faber, Hendrik; Klaumünzer, Martin; Voigt, Michael; Galli, Diana; Vieweg, Benito F; Peukert, Wolfgang; Spiecker, Erdmann; Halik, Marcus

2011-03-01

Zinc oxide thin-films are prepared either by spin coating of an ethanolic dispersion of nanoparticles (NP, diameter 5 nm) or by spray pyrolysis of a zinc acetate dihydrate precursor. High-resolution electron microscopy studies reveal a monolayer of particles for the low temperature spin coating approach and larger crystalline domains of more than 30 nm for the spray pyrolysis technique. Thin-film transistor devices (TFTs) based on spray pyrolysis films exhibit higher electron mobilities of up to 24 cm2 V(-1) s(-1) compared to 0.6 cm2 V(-1) s(-1) for NP based TFTs. These observations were dedicated to a reduced number of grain boundaries within the transistor channel.

Flame spray pyrolysis for sensing at the nanoscale.

PubMed

Kemmler, J A; Pokhrel, S; Mädler, L; Weimar, U; Barsan, N

2013-11-08

Progress in developing novel gas sensors based on semiconducting metal oxides (SMOX) has been hindered by the cumbersome fabrication technologies currently employed. They involve time intensive synthesis procedures for gaining sensitive materials and preparation of the inks employed for realizing sensing layers. In this paper we review the opportunities offered by the relatively young method of flame spray pyrolysis, with which it is possible not only to synthesize a broad selection of SMOX in pure or doped form, but also to simultaneously deposit thick and highly porous gas sensitive films on a variety of substrates. In less than ten years the properties of nine base materials have been evaluated for all most relevant target gases and the obtained results are promising for future development.

Flame spray pyrolysis for sensing at the nanoscale

NASA Astrophysics Data System (ADS)

Kemmler, J. A.; Pokhrel, S.; Mädler, L.; Weimar, U.; Barsan, N.

2013-11-01

Progress in developing novel gas sensors based on semiconducting metal oxides (SMOX) has been hindered by the cumbersome fabrication technologies currently employed. They involve time intensive synthesis procedures for gaining sensitive materials and preparation of the inks employed for realizing sensing layers. In this paper we review the opportunities offered by the relatively young method of flame spray pyrolysis, with which it is possible not only to synthesize a broad selection of SMOX in pure or doped form, but also to simultaneously deposit thick and highly porous gas sensitive films on a variety of substrates. In less than ten years the properties of nine base materials have been evaluated for all most relevant target gases and the obtained results are promising for future development.

Studies on annealed ZnO:V thin films deposited by nebulised spray pyrolysis method

NASA Astrophysics Data System (ADS)

Malini, D. Rachel

2018-04-01

Structural, optical and photoluminescence properties of annealed ZnO:V thin films deposited by nebulized spray pyrolysis technique by varying vanadium concentration are studied. Thickness of thin films varies from 1.52µm to 7.78µm. V2O5, VO2 and ZnO peaks are observed in XRD patterns deposited with high vanadium concentration and the intensity of peaks corresponding to ZnO decreases in those samples. Morphological properties were studied by analysing SEM images and annealed thin films deposited at ZnO:V = 50:50 possess dumb bell shape grains. Emission peaks corresponding to both Augur transition and deep level transition are observed in the PL spectra of the samples.

Tailoring of optical band gap by varying Zn content in Cd{sub 1-x}Zn{sub x}S thin films prepared by spray pyrolysis method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, Vipin, E-mail: vipinkumar28@yahoo.co.in; Sharma, D. K.; Agrawal, Sonalika

Cd{sub 1-X}Zn{sub X}S thin films (X = 0.2, 0.4, 0.6, 0.8) have been grown on glass substrate by spray pyrolysis technique using equimolar concentration aqueous solution of cadmium chloride, zinc acetate and thiourea. Prepared thin films have been characterized by UV-VIS spectrophotometer. The optical band gap of the films has been studied by transmission spectra in wavelength range 325-600nm. It has been observed that optical band gap increases with increasing zinc concentration. The optical band gap of these thin films varies from 2.59 to 3.20eV with increasing Zn content.

Fabrication, characterization and applications of iron selenide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hussain, Raja Azadar, E-mail: hussainazadar@yahoo.com; Badshah, Amin; Lal, Bhajan

This review article presents fabrication of FeSe by solid state reactions, solution chemistry routes, chemical vapor deposition, spray pyrolysis and chemical vapor transport. Different properties and applications such as crystal structure and phase transition, band structure, spectroscopy, superconductivity, photocatalytic activity, electrochemical sensing, and fuel cell activity of FeSe have been discussed. - Graphical abstract: Iron selenide can be synthesized by solid state reactions, chemical vapor deposition, solution chemistry routes, chemical vapor transport and spray pyrolysis. - Highlights: • Different fabrication methods of iron selenide (FeSe) have been reviewed. • Crystal structure, band structure and spectroscopy of FeSe have been discussed.more » • Superconducting, catalytic and fuel cell application of FeSe have been presented.« less

Modifying Optical Properties of ZnO Films by Forming Zn[subscript 1-x] Co[subscript x]O Solid Solutions via Spray Pyrolysis

ERIC Educational Resources Information Center

Bentley, Anne K.; Weaver, Gabriela C.; Russell, Cianan B.; Fornes, William L.; Choi, Kyoung-Shin; Shih, Susan M.

2007-01-01

A simple and cost-effective experiment for the development and characterization of semiconductors using Uv-vis spectroscopy is described. The study shows that the optical properties of ZnO films can be easily modified by forming Zn[subscript 1-x] Co[subscript x]O solid solutions via spray pyrolysis.

Intelligent Processing of Ferroelectric Thin Films

DTIC Science & Technology

1993-09-03

the acetate precursors. The results from these experiments involving coprecipitation, hydrothermal , spray pyrolysis and freeze drying have shown that...Spray Pyrolysis (SP) D. Hydrothermal Processing (HP) The powder produced by each process was characterized by X-ray diffraction (XRD) and scanning...precursors were used as described above. Instead of ammonia solution, an oxalic acid solution was used as the3 precipitating agent. The precipitants

Fabricate heterojunction diode by using the modified spray pyrolysis method to deposit nickel-lithium oxide on indium tin oxide substrate.

PubMed

Wu, Chia-Ching; Yang, Cheng-Fu

2013-06-12

P-type lithium-doped nickel oxide (p-LNiO) thin films were deposited on an n-type indium tin oxide (ITO) glass substrate using the modified spray pyrolysis method (SPM), to fabricate a transparent p-n heterojunction diode. The structural, optical, and electrical properties of the p-LNiO and ITO thin films and the p-LNiO/n-ITO heterojunction diode were characterized by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), UV-visible spectroscopy, Hall effect measurement, and current-voltage (I-V) measurements. The nonlinear and rectifying I-V properties confirmed that a heterojunction diode characteristic was successfully formed in the p-LNiO/n-ITO (p-n) structure. The I-V characteristic was dominated by space-charge-limited current (SCLC), and the Anderson model demonstrated that band alignment existed in the p-LNiO/n-ITO heterojunction diode.

Improved performance of low cost CuInS2 superstrate-type solar cells using Zinc assisted spray pyrolysis processing

NASA Astrophysics Data System (ADS)

Cheshme Khavar, Amir Hossein; Mahjoub, Ali Reza; Taghavinia, Nima

2017-12-01

Superstrate configuration CuInS2 (CIS) solar cells are fabricated using a spray pyrolysis method. We avoided selenization process, cyanide etching and CdS buffer layer, to keep the process ‘green’. CIS layers are formed by spray pyrolysis of an aqueous precursor ink containing metal chloride salts and thiourea at 350 °C. We investigated the effect of intentional Zn doping on structural, morphological and photovoltaic response of the fabricated CIS films by dissolving ZnCl2 in aqueous precursor solution. At a zinc doping level ranging between 0.25 and 1.00 mol%, Zn doping is found to improve the CIS crystal growth and surface morphology of CIS films. Compared with the performance of the non-doped CIS cell, the Zn-doped CIS solar cell displayed a remarkable efficiency enhancement of 58-97% and the maximum enhancement was obtained at a Zn content of 0.5 mol%. The device structure consists of    and show promising PCE of 4.29 % without any anti-reflection coating. Over the course of 300 d under ambient condition, the fabricated device showed only 1% loss in efficiency.

Corrosion resistance of zirconium oxynitride coatings deposited via DC unbalanced magnetron sputtering and spray pyrolysis-nitriding

NASA Astrophysics Data System (ADS)

Cubillos, G. I.; Bethencourt, M.; Olaya, J. J.

2015-02-01

ZrOxNy/ZrO2 thin films were deposited on stainless steel using two different methods: ultrasonic spray pyrolysis-nitriding (SPY-N) and the DC unbalanced magnetron sputtering technique (UBMS). Using the first method, ZrO2 was initially deposited and subsequently nitrided in an anhydrous ammonia atmosphere at 1023 K at atmospheric pressure. For UBMS, the film was deposited in an atmosphere of air/argon with a Φair/ΦAr flow ratio of 3.0. Structural analysis was carried out through X-ray diffraction (XRD), and morphological analysis was done through scanning electron microscopy (SEM) and atomic force microscopy (AFM). Chemical analysis was carried out using X-ray photoelectron spectroscopy (XPS). ZrOxNy rhombohedral polycrystalline film was produced with spray pyrolysis-nitriding, whereas using the UBMS technique, the oxynitride films grew with cubic Zr2ON2 crystalline structures preferentially oriented along the (2 2 2) plane. Upon chemical analysis of the surface, the coatings exhibited spectral lines of Zr3d, O1s, and N1s, characteristic of zirconium oxynitride/zirconia. SEM analysis showed the homogeneity of the films, and AFM showed morphological differences according to the deposition technique of the coatings. Zirconium oxynitride films enhanced the stainless steel's resistance to corrosion using both techniques. The protective efficacy was evaluated using electrochemical techniques based on linear polarization (LP). The results indicated that the layers provide good resistance to corrosion when exposed to chloride-containing media.

One-step synthesis of bioactive glass by spray pyrolysis

NASA Astrophysics Data System (ADS)

Shih, Shao-Ju; Chou, Yu-Jen; Chien, I.-Chen

2012-12-01

Bioactive glasses (BGs) have recently received more attention from biologists and engineers because of their potential applications in bone implants. The sol-gel process is one of the most popular methods for fabricating BGs, and has been used to produce BGs for years. However, the sol-gel process has the disadvantages of discontinuous processing and a long processing time. This study presented a one-step spray pyrolysis (SP) synthesis method to overcome these disadvantages. This SP method has synthesized spherical bioactive glass (SBG) and mesoporous bioactive glass (MBG) particles using Si-, Ca- and P-based precursors. This study used transmission electron microscopy, selected area electron diffraction and X-ray dispersive spectroscopy to characterize the microstructure, crystallographic structure, and chemical composition for the BG particles. In addition, in vitro bioactive tests showed the formation of hydroxyl apatite layers on SBG and MBG particles after immersion in simulated body fluid for 5 h. Experimental results show the SP formation mechanisms of SBG and MBG particles.

Characteristics of Fe powders prepared by spray pyrolysis from a spray solution with ethylene glycol as the source material of heat pellet

NASA Astrophysics Data System (ADS)

Koo, H. Y.; Kim, J. H.; Hong, S. K.; Ko, Y. N.; Jang, H. C.; Jung, D. S.; Han, J. M.; Hong, Y. J.; Kang, Y. C.; Kang, S. H.; Cho, S. B.

2012-06-01

Fe powders as the heat pellet material for thermal batteries are prepared from iron oxide powders obtained by spray pyrolysis from a spray solution of iron nitrate with ethylene glycol. The iron oxide powders with hollow and thin wall structure produce Fe powders with elongated structure and fine primary particle size at a low reducing temperature of 615 °C. The mean size of the primary Fe powders with elongated structure decreases with increasing concentration of ethylene glycol dissolved into the spray solution. The heat pellets prepared from the fine-size Fe powders with elongated structure have good ignition sensitivities below 1 watt. The heat pellets formed from the Fe powders obtained from the spray solution with 0.5 M EG have an extremely high burn rate of 26 cms-1.

Antimony-Doped Tin Oxide Thin Films Grown by Home Made Spray Pyrolysis Technique

NASA Astrophysics Data System (ADS)

Yusuf, Gbadebo; Babatola, Babatunde Keji; Ishola, Abdulahi Dimeji; Awodugba, Ayodeji O.; Solar cell Collaboration

2016-03-01

Transparent conducting antimony-doped tin oxide (ATO) films have been deposited on glass substrates by home made spray pyrolysis technique. The structural, electrical and optical properties of the ATO films have been investigated as a function of Sb-doping level and annealing temperature. The optimum target composition for high conductivity and low resistivity was found to be 20 wt. % SnSb2 + 90 wt. ATO. Under optimized deposition conditions of 450oC annealing temperature, electrical resistivity of 5.2×10-4 Ω -cm, sheet resistance of 16.4 Ω/sq, average optical transmittance of 86% in the visible range, and average optical band-gap of 3.34eV were obtained. The film deposited at lower annealing temperature shows a relatively rough, loosely bound slightly porous surface morphology while the film deposited at higher annealing temperature shows uniformly distributed grains of greater size. Keywords: Annealing, Doping, Homemade spray pyrolysis, Tin oxide, Resistivity

Effects of Y/Gd Ratio and Boron Excess on Vacuum Ultraviolet Characteristics and Morphology of (Y,Gd)BO3:Eu Phosphor Particles Prepared by Spray Pyrolysis

NASA Astrophysics Data System (ADS)

Koo, Hye Young; Jung, Dae Soo; Hong, Seung Kwon; Kang, Yun Chan; Jung, Kyeong Youl

2007-06-01

(Y1-xGdx)BO3:Eu (0≤ x≤ 1) phosphor particles were prepared by spray pyrolysis. The optimal amount of boric acid for the high photoluminescence intensity of there particles differed depending on the molar ratio of Y to Gd. With decreasing Y/Gd molar ratio, an increasing amount of excess boric acid was required. The difference in excess quantity of boric acid, which was demanded for the highest photoluminescence intensity according to the Y/Gd ratio, influenced the morphology and mean size of the (Y,Gd)BO3:Eu phosphor particles. The (Y1-xGdx)BO3:Eu (0≤ x≤ 1) phosphor particles had a regular morphology. The mean sizes of the GdBO3:Eu and YBO3:Eu phosphor particles were 1.4 and 1 μm, respectively. The high reactivity of boron and yttrium components produced YBO3:Eu phosphor particles with high photoluminescence intensities by spray pyrolysis using a spray solution with a stoichiometric amount of boric acid.

Crumpled rGO-supported Pt-Ir bifunctional catalyst prepared by spray pyrolysis for unitized regenerative fuel cells

NASA Astrophysics Data System (ADS)

Kim, In Gyeom; Nah, In Wook; Oh, In-Hwan; Park, Sehkyu

2017-10-01

Three-dimensional (3D) crumpled reduced graphene oxide supported Pt-Ir alloys that served as bifunctional oxygen catalysts for use in untized regenerative fuel cells were synthesized by a facile spray pyrolysis method. Pt-Ir catalysts supported on rGO (Pt-Ir/rGOs) were physically characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA) to observe change in composition by heat treatment, alloying, and morphological transition of the catalysts. Their catalytic activities and stabilities for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) conditions were electrochemically investigated using cyclic voltammetry (CV), linear sweep voltammetry (LSV), potential cycling and hold tests on the rotating disk electrode (RDE). Pt-Ir/rGO with no post heat-treatment (Pt-Ir/rGO_NP) showed a lower activity for ORR and OER although metal nanoparticles decorated on the support are relatively small. However, Pt-Ir/rGO showed remarkably enhanced activity following heat treatment, depending on temperature. Pt-Ir/rGO heat-treated at 600 °C after spray pyrolysis (Pt-Ir/rGO_P600) exhibited a higher activity and stability than a commercially available Pt/C catalyst kept under the ORR condition, and it also revealed a comparable OER activity and durability versus the commercial unsupported Ir catalyst.

Fabrication and performance of Li4Ti5O12/C Li-ion battery electrodes using combined double flame spray pyrolysis and pressure-based lamination technique

NASA Astrophysics Data System (ADS)

Gockeln, Michael; Pokhrel, Suman; Meierhofer, Florian; Glenneberg, Jens; Schowalter, Marco; Rosenauer, Andreas; Fritsching, Udo; Busse, Matthias; Mädler, Lutz; Kun, Robert

2018-01-01

Reduction of lithium-ion battery (LIB) production costs is inevitable to make the use of LIB technology more viable for applications such as electric vehicles or stationary storage. To meet the requirements in today's LIB cost efficiency, our current research focuses on an alternative electrode fabrication method, characterized by a combination of double flame spray pyrolysis and lamination technique (DFSP/lamination). In-situ carbon coated nano-Li4Ti5O12 (LTO/C) was synthesized using versatile DFSP. The as-prepared composite powder was then directly laminated onto a conductive substrate avoiding the use of any solvent or binder for electrode preparation. The influence of lamination pressures on the microstructure and electrochemical performance of the electrodes was also investigated. Enhancements in intrinsic electrical conductivity were found for higher lamination pressures. Capacity retention of highest pressurized DFSP/lamination-prepared electrode was 87.4% after 200 dis-/charge cycles at 1C (vs. Li). In addition, LTO/C material prepared from the double flame spray pyrolysis was also used for fabricating electrodes via doctor blading technique. Laminated electrodes obtained higher specific discharge capacities compared to calendered and non-calendered blade-casted electrodes due to superior microstructural properties. Such a fast and industrially compelling integrative DFSP/lamination tool could be a prosperous, next generation technology for low-cost LIB electrode fabrication.

Flash Vacuum Pyrolysis: Techniques and Reactions.

PubMed

Wentrup, Curt

2017-11-20

Flash vacuum pyrolysis (FVP) had its beginnings in the 1940s and 1950s, mainly through mass spectrometric detection of pyrolytically formed free radicals. In the 1960s many organic chemists started performing FVP experiments with the purpose of isolating new and interesting compounds and understanding pyrolysis processes. Meanwhile, many different types of apparatus and techniques have been developed, and it is the purpose of this review to present the most important methods as well as a survey of typical reactions and observations that can be achieved with the various techniques. This includes preparative FVP, chemical trapping reactions, matrix isolation, and low temperature spectroscopy of reactive intermediates and unstable molecules, the use of online mass, photoelectron, microwave, and millimeterwave spectroscopies, gas-phase laser pyrolysis, pulsed pyrolysis with supersonic jet expansion, very low pressure pyrolysis for kinetic investigations, solution-spray and falling-solid FVP for involatile compounds, and pyrolysis over solid supports and reagents. Moreover, the combination of FVP with matrix isolation and photochemistry is a powerful tool for investigations of reaction mechanism. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

High crystalline CuAlS2 thin films via chemical spray pyrolysis route

NASA Astrophysics Data System (ADS)

Naveena, D.; Logu, T.; Sethuraman, K.; Bose, A. Chandra

2018-04-01

High crystalline and non-toxic CuAlS2 thin films were successfully deposited on glass substrate by chemical spray pyrolysis method. The as-prepared sample was subjected to the sulphurization at 450 °C for 30 min. The structural, morphological, optical and electrical properties of the as deposited and sulphurized films have been systematically analyzed. XRD result shows that the sulphurized sample exhibited tetragonal crystal structure with increase in crystallite size. The optical band gap was found to decrease from 3.25 eV to 3.21 eV and the carrier concentration is 4.22×1015cm-3 for the as-deposited film which rises to 6.29×1015cm-3 after sulphurizing the film in nitrogen atmosphere. The results of this study provide a framework for fabricating an optimized high crystalline CuAlS2 layer in optoelectronic devices.

Resistance to Corrosion of Zirconia Coatings Deposited by Spray Pyrolysis in Nitrided Steel

NASA Astrophysics Data System (ADS)

Cubillos, G. I.; Olaya, J. J.; Bethencourt, M.; Cifredo, G.; Blanco, G.

2013-10-01

Coatings of zirconium oxide were deposited onto three types of stainless steel, AISI 316L, 2205, and tool steel AISI D2, using the ultrasonic spray pyrolysis method. The effect of the flux ratio on the process and its influence on the structure and morphology of the coatings were investigated. The coatings obtained, 600 nm thick, were characterized using x-ray diffraction, scanning electron microscopy, confocal microscopy, and atomic force microscopy. The resistance to corrosion of the coatings deposited over steel (not nitrided) and stainless steel nitrided (for 2 h at 823 K) in an ammonia atmosphere was evaluated. The zirconia coating enhances the stainless steel's resistance to corrosion, with the greatest increase in corrosion resistance being observed for tool steel. When the deposition is performed on previously nitrided stainless steel, the morphology of the surface improves and the coating is more homogeneous, which leads to an improved corrosion resistance.

Nanostructured ZnO films with various morphologies prepared by ultrasonic spray pyrolysis and its growing process

NASA Astrophysics Data System (ADS)

Ma, H. L.; Liu, Z. W.; Zeng, D. C.; Zhong, M. L.; Yu, H. Y.; Mikmekova, E.

2013-10-01

Nanostructured ZnO films were prepared by the ultrasonic spray pyrolysis method using Zn(CH3COO)2·2H2O as a precursor. The effects of substrate temperature (Ts) on the morphology and properties were systematically studied. As the Ts increased from 430 °C to 610 °C, the morphology of the film transforms from closed packed nanosheets to dense nanocrystalline film and then to hexagonal nanorod array. The dense film formed at a temperature of 550 °C has the lowest electric resistivity and highest carrier concentration. The optical transmittance for all prepared samples was higher than 90%. The photoluminescence (PL) properties varied with the Ts due to the internal defect difference. The growth mechanism of ZnO film involves island growth and diffusion, which was evident by observing the samples prepared at various times.

Synthesis of ZnO Hexagonal Micro Discs on Glass Substrates Using the Spray Pyrolysis Technique

NASA Astrophysics Data System (ADS)

Ikhmayies, Shadia J.; Zbib, Mohamad B.

2017-07-01

Zinc oxide (ZnO) is an important transparent conducting oxide of potential use in solar cells, electronics, photoelectronics, and sensors. In this work ZnO micro discs were synthesized in thin film form on glass substrates using the low cost spray pyrolysis method. The films were prepared from a precursor solution of ZnCl2 in distilled water at a substrate temperature of 300 ± 5°C. The as-synthesized samples were analyzed with x-ray diffraction, scanning electron microscopy, and x-ray energy dispersive spectroscopy (EDS). The morphology of the films showed randomly distributed micro discs of hexagonal shape. The EDS reports showed that the films contained Cl and Fe. Size analysis was performed using ImageJ software, where the average diameter was found to be 4.8 ± 0.9 μm, and the average thickness was found to be 254 ± 43 nm.

Synthesis of V2O5 microspheres by spray pyrolysis as cathode material for supercapacitors

NASA Astrophysics Data System (ADS)

Yin, Zhendong; Xu, Jie; Ge, Yali; Jiang, Qiaoya; Zhang, Yaling; Yang, Yawei; Sun, Yuping; Hou, Siyu; Shang, Yuanyuan; Zhang, Yingjiu

2018-03-01

Vanadium oxide (V2O5) microspheres have attracted considerable attention in the energy field due to their unique properties such as high stability and electrochemical activity. Here, massive V2O5 microspheres with smooth surface, hollow cavity and uniform particle sizes (0.4–1.5 μm), were synthesized by a facile spray pyrolysis process. Post-treatment at predefined temperatures effectively turned the microsphere shell into stacked nanorods with widths of 100 nm and lengths of 500 nm when processed at 500 °C for 3 h under nitrogen atmosphere, with enhanced crystallinity. When applied as cathode materials for supercapacitors, the post-treated V2O5 microspheres at 500 °C exhibited improved specific capacitance and longer discharge time. This is an effective method to manufacture massive V2O5 microspheres with tailored structure and potential applications in high-performance energy storage materials.

Y2O3:Eu phosphor particles prepared by spray pyrolysis from a solution containing citric acid and polyethylene glycol

NASA Astrophysics Data System (ADS)

Roh, H. S.; Kang, Y. C.; Park, H. D.; Park, S. B.

Y2O3:Eu phosphor particles were prepared by large-scale spray pyrolysis. The morphological control of Y2O3:Eu particles in spray pyrolysis was attempted by adding polymeric precursors to the spray solution. The effect of composition and amount of polymeric precursors on the morphology, crystallinity and photoluminescence characteristics of Y2O3:Eu particles was investigated. Particles prepared from a solution containing polyethylene glycol (PEG) with an average molecular weight of 200 had a hollow structure, while those prepared from solutions containing adequate amounts of citric acid (CA) and PEG had a spherical shape, filled morphology and clean surfaces after post-treatment at high temperature. Y2O3:Eu particles prepared from an aqueous solution with no polymeric precursors had a hollow structure and rough surfaces after post-treatment. The phosphor particles prepared from solutions with inadequate amounts of CA and/or PEG also had hollow and/or fragmented structures. The particles prepared from the solution containing 0.3 M CA and 0.3 M PEG had the highest photoluminescence emission intensity, which was 56% higher than that of the particles prepared from aqueous solution without polymeric precursors.

Elaboration et caracterisation de couches minces de CuInS2 deposees par la pyrolyse par pulverisation ultrasonique a base de transducteur

NASA Astrophysics Data System (ADS)

Petuenju, Eric Nguwuo

The present thesis study is part of the work of The Laboratory of New Materials for Energy and Electrochemistry systems (LaNoMat) that search new techniques to elaborate new materials for photovoltaic solar applications. This aims contribute to the development of the exploitation of solar energy into electrical energy by the maximum of the population throughout the world. This work deals with the determination of CuInS2 thin film deposition parameters by ultrasonic spray pyrolysis method for applications in the technology of three dimensional (3D) solar cells. The structure of the band gap of CuInS2 (a semiconductor material with a direct bandgap of 1.55 eV) makes it an excellent candidate for the role of the absorber in thin film technology for solar photovoltaic applications. 3D solar photovoltaic technology requires the production of a p-n junction with n and p-type semiconductors to make networks. The production and growth of such networks depends on the creation of thin films which have the characteristics of an ultrathin nanocomposite or extremely thin absorber (typically a few tens of nanometers) or which act as a quantum dot. To allow the emergence of 3D photovoltaic technology, it is important to develop methods for the growth of thin layers of materials such as CuInS 2, which are potentially interesting for this purpose. But the development of methods for thin film deposition, for the reasons of competition and accessibility, must be considered as an important factor in the context of the development of three-dimensional photovoltaic solar cells at low cost (production costs: of the order of 0,5 a 0,3$US/Watt-peak) (Beard et al., 2014). To do this it is necessary to use materials manufacturing technology readily available and inexpensive, and allowing to have materials on large surface, such as pyrolysis which allows to reduce costs by a factor of 100 compared to the crystallogenesis. Pyrolysis is defined as a process for decomposing one or more compounds by heat to obtain the formation of a new compound. The main objective of this thesis focuses on the use of ultrasonic spray pyrolysis technique to grow CuInS2 thin films and characterize them by different techniques. This choice is linked to the fact that the CuInS2 is a direct gap semiconductor material, which can act as absorber in solar photovoltaic technology. However, the growth of thin films of this material is subject to a problem of creation of interpenetrating networks of different types of semiconductors (n and p-type), which implies a suitable choice of deposition technique. It should be noted that the interest in existing methods, the ALCVD (Atomic Layer Vapor Deposition) and ILGAR (Ion Layer Gas Reaction) developed in paragraphs 2.4.1 and 2.4.2, is confronted with time limits of these methods. Indeed these two methods, owing to the principle of sequential production process, take place very slowly; and we showed that the thickness of the obtained thin film is proportional to the deposition time. In this work, spray pyrolysis is carried out in two different ways, namely ultrasonic and pneumatic spraying. Of these two methods, we showed that the transducer based ultrasonic spray pyrolysis is the method that can be used to grow thin films of CuInS2 a good homogeneity of the crystallites size (of the order of 110 A) and the morphology of the layers. Ultrasonic spraying was done with a piezoelectric system using a transducer. This system consists of a cylindrical container made of Teflon 5 cm diameter and 15 cm long in which is introduced the solution containing the precursor. The container is mounted on an ultrasonic transducer, component of the piezoelectric system TDK nebulizer unit NB-80E-01, which transforms the solution in aerosol. The aerosol is transported through a teflon tube by a carrier gas, the nitrogen, into a floating motion to the substrate. The substrate is placed on a heating plate whose temperature is controlled by a control monitor. The supply in solution of the container is done with the aid of an electric pump. The nature of the samples obtained is dependent of the supporting electrolyte for the deposition of the precursors. We showed that the use of precursors in an aqueous solution leads to the production of thin layers of indium sulfide In 2S3 clusters while the use of the precursors in alcoholic solution leads to the production of thin layers of CuInS2. The precursors ratio for deposition of CuInS2 is Cu: In: S = 1: 1: 4. The thickness of thin films of In2S3 is of the order of 812 nm. These layers are composed of microaggregates with size ranging from 3 to 20 microns. The particle size in the thin films of In2S 3 is of about 220 A. The thickness of the thin film of CuInS 2 is of the order of 600 nm. Spectrophotometry has identified that all obtained CuInS2 thin films have an average band gap value of 1.40 eV. This indicates the presence of intermediate states, such as copper vacancies in the material band gap. The absorption spectra also allowed us to distinguish peaks that can be attributed to the contribution of sub-bands corresponding to the indium-sulfur bond and the sulfur 3s-band. The samples were characterized by X-ray Diffraction to identify crystalline structure while their surface morphology as well as their semi-quantitative chemical composition were determined using the energy-dispersive x-ray spectroscopy. The ensuing results show that the thin films obtained are homogeneous, transparent and polycrystalline with the crystallites size of the order of 110 A. The thin films obtained by this method do not require annealing to improve their crystallinity. The growth of thin films depends on the substrate humidification period. For a wetting time of about 3 minutes, thin layers are obtained with stoichiometry of Cu: In: S = 1: 1.81: 3.18. The obtained samples are indexed as CIS1. For a wetting time of about 7 minutes, thin layers are obtained with stoichiometry of Cu: In: S = 1: 1.23: 2.07. The obtained samples are indexed as CIS2. Contrary to layers CIS1, the layers CIS2 also contain chlorine. The obtained thin films are p-type and, under illumination of 100 mW/cm 2 by a xenon lamp, an increase of the density of charge carriers of about 62% is obtained, but this value does not account the recombination phenomena. In the case of the pneumatic spraying method, the spraying principle is based on the application of Venturi effect, which allows to spray the solution of precursors using a carrier gas. This method is called gas blasting spray pyrolysis. The gas used here is nitrogen. The sprayer is an airbrush - Iwata hp-eclipse bcs - which aspires the solution through a tube connected to the bottle containing the precursor solution, and sprays it through a nozzle according to the principle of the Venturi effect. The precursors ratio is Cu:In:S=1:1:4. The obtained thin films are CuInS2. They are heterogeneous, dense, opaque, and polycrystalline with a crystallites size of the order of 550 A. The stoichiometry of the obtained layers is of order of 1:1.45:2.28. The thin films obtained by this method require annealing (heating of the samples in an oven for one hour at a temperature of 300 ° C) to improve their crystallinity. The thickness of the obtained thin film of CuInS2 is of the order of 1190 nm. The comparative analysis of the samples obtained by the two types of spray pyrolysis is then performed. It shows that ultrasonic aerosol spray would provide CuInS2 thin films for solar applications both in the roles of nanocomposite ultra-thin absorber and extremely thin absorber as in that of quantum dot absorber. In conclusion, transducer based ultrasonic spray pyrolysis is therefore a method that would allow the deposition of CuInS2 on TiO 2 and contribute to resolve a major limitation in three-dimensional photovoltaic solar cells technology, namely the realization of interpenetrating networks of n-type and p-type semiconductors, on a large scale and without time constraint.

Influence of solution deposition rate on properties of V2O5 thin films deposited by spray pyrolysis technique

NASA Astrophysics Data System (ADS)

Abd-Alghafour, N. M.; Ahmed, Naser M.; Hassan, Zai; Mohammad, Sabah M.

2016-07-01

Vanadium oxide (V2O5) thin films were deposited on glass substrates by using a cost-efficient spray pyrolysis technique. The films were grown at 350° through thermal decomposition of VCl3 in deionized water with different solution spray rates. The high resolution X-ray diffraction results revealed the formation of nanocrystalline films having orthorhombic structures with preferential orientation along (101) direction. The spray rate influenced the surface morphology and crystallite size of the films. The crystallite size was found to increase whereas the micro-strain was decreased by increasing the spray deposition rates. The increase in crystallite size and decrease in the macrostrain resulted in an improvement in the films' crystallinity. The UV-Visible spectroscopy analysis indicated that the average transmittance of all films lies in the range 75-80 %. The band gap of V2O5 film was decreased from 2.65 to 2.46 eV with increase of the spray deposition rate from 5 ml/min to 10 ml/min. first, second, and third level headings (first level heading).

Photoactive lead oxide thin films by spray pyrolysis

NASA Astrophysics Data System (ADS)

Bhagat, Dharini; Waldiya, Manmohansingh; Mukhopadhyay, Indrajit

2018-05-01

We report the synthesis of photoactive lead monoxide thin films on fluorine doped tin oxide substrate by cost effective spray pyrolysis technique using aqueous solution of lead acetate trihydrate. Influence of substrate temperature on the structural and optical properties of thin films was studied. Polymorph of lead monoxide, litharge (α-PbO), was obtained when the substrate temperature was kept constant at 360 °C. XRD analysis revealed that the deposits were tetragonal structured with preferred orientation along 002 plane. Band gap value was found to be 1.93ev from diffuse reflectance spectra.

Sb2S3 grown by ultrasonic spray pyrolysis and its application in a hybrid solar cell

PubMed Central

Katerski, Atanas; Oja Acik, Ilona; Mere, Arvo; Mikli, Valdek; Krunks, Malle

2016-01-01

Chemical spray pyrolysis (CSP) is a fast wet-chemical deposition method in which an aerosol is guided by carrier gas onto a hot substrate where the decomposition of the precursor chemicals occurs. The aerosol is produced using an ultrasonic oscillator in a bath of precursor solution and guided by compressed air. The use of the ultrasonic CSP resulted in the growth of homogeneous and well-adhered layers that consist of submicron crystals of single-phase Sb2S3 with a bandgap of 1.6 eV if an abundance of sulfur source is present in the precursor solution (SbCl3/SC(NH2)2 = 1:6) sprayed onto the substrate at 250 °C in air. Solar cells with glass-ITO-TiO2-Sb2S3-P3HT-Au structure and an active area of 1 cm2 had an open circuit voltage of 630 mV, short circuit current density of 5 mA/cm2, a fill factor of 42% and a conversion efficiency of 1.3%. Conversion efficiencies up to 1.9% were obtained from solar cells with smaller areas. PMID:28144515

Photoluminescence in Spray Pyrolysis Deposited β-In2S3 Thin Films

NASA Astrophysics Data System (ADS)

Jayakrishnan, R.

2018-04-01

Spray pyrolysis deposited In2S3 thin films exhibit two prominent photoluminescent emissions. One of the emissions is green in color and centered at around ˜ 540 nm and the other is centered at around ˜ 690 nm and is red in color. The intensity of the green emission decreases when the films are subjected to annealing in air or vacuum. The intensity of red emission increases when films are air annealed and decreases when vacuum annealed. Vacuum annealing leads to an increase in work function whereas air annealing leads to a decrease in work function for this thin film system relative to the as deposited films indicating changes in space charge regions. Surface photovoltage analysis using a Kelvin probe leads to the conclusion that inversion of band bending occurs as a result of annealing. Correlating surface contact potential measurements using a Kelvin probe, x-ray photoelectron spectroscopy and photoluminescence, we conclude that the surface passivation plays a critical role in controlling the photoluminescence from the spray pyrolysis deposited for In2S3 thin films.

Synthesis and photocatalytic property of Zinc Oxide (ZnO) fine particle using flame spray pyrolysis method

NASA Astrophysics Data System (ADS)

Widiyandari, Hendri; Ayu Ketut Umiati, Ngurah; Dwi Herdianti, Rizki

2018-05-01

Advance oxidation process (AOP) using photocatalysis constitute a promising technology for the treatment of wastewaters containing non-easily removable organic compound. Zinc oxide (ZnO) is one of efficient photocatalyst materials. This research reported synthesis of ZnO fine particle from zinc nitrate hexahydrate using Flame Spray Pyrolysis (FSP) method. In this method, oxygen (O2) gas were used as oxidizer and LPG (liquid petroleum gas) were used as fuel. The effect of O2 gas flow rate during ZnO particle fabrication to the microstructure, optical and photocatalytic properties were systematically discussed. The photocatalytic activity of ZnO was tested for the degradation of amaranth dye with initial concentration of 10 ppm under irradiation of solar simulator. The rate of decrease in amaranth concentration was measured using UV-Visible spectrophotometer. The ZnO synthesized using FSP has a hexagonal crystalline structure. Scanning electron microscope images showed that ZnO has a spherical formed which was the mixture of solid and hollow particles. The optimum condition for amaranth degradation was shown by ZnO produced at a flow rate of 1.5 L/min which able to degrade amaranth dye up to 95,3 % at 75 minutes irradiation.

Properties of mixed molybdenum oxide iridium oxide thin films synthesized by spray pyrolysis

NASA Astrophysics Data System (ADS)

Patil, P. S.; Kawar, R. K.; Sadale, S. B.; Inamdar, A. I.; Deshmukh, H. P.

2006-09-01

Molybdenum-doped iridium oxide thin films have been deposited onto corning glass- and fluorine-doped tin oxide coated corning glass substrates at 350 °C by using a pneumatic spray pyrolysis technique. An aqueous solution of 0.01 M ammonium molybdate was mixed with 0.01 M iridium trichloride solution in different volume proportions and the resultant solution was used as a precursor solution for spraying. The as-deposited samples were annealed at 600 °C in air medium for 1 h. The structural, electrical and optical properties of as-deposited and annealed Mo-doped iridium oxide were studied and values of room temperature electrical resistivity, and thermoelectric power were estimated. The as-deposited samples with 2% Mo doping exhibit more pronounced electrochromism than other samples, including pristine Ir oxide.

Effect of concentration and irradiation on the optical and structural properties of ZnO thin films deposited by spray pyrolysis techniques

NASA Astrophysics Data System (ADS)

Adeoye Victor, Babalola

2017-12-01

This study involves the preparation of ZnO thin films by spray pyrolysis and to investigate the effect of concentration of the film and irradiation on ZnO thin film deposited by spray pyrolysis method deposited at 350 ± 5 °C. The precursor for zinc oxide was produced from zinc acetate (Zn(CH3COO))2. The samples were annealed at 500 °C for 6 h and irradiated using 137Cs 90.998 mCi radiation. They were then characterised using ultra violet-visible spectrophotometry, X-ray Diffractometry (XRD) with Cu-Kα radiation to determine the structure of the film, Four-point probe for electrical properties and Rutherford Backscattering Spectrometry (RBS) were used for the composition of the film. XRD diffraction peaks observed for 0.05 M ZnO were (1 0 0), (0 0 2), (1 0 1) and (1 1 0) planes for the annealed and irradiated annealed ZnO films with no preferential orientation. The as-deposited films have low peaks belonging to (1 0 0), (0 0 2), (1 0 1), (1 1 0) plane and other peaks such as (1 1 2), (2 0 0) and (2 0 1). The results are explained with regard to the irradiation damage introduced to the samples. The as-deposited, annealed and irradiated-annealed films are highly transparent in the visible range of the electromagnetic spectrum with an average percent transmittance values of 85% and present a sharp ultraviolet cut-off at approximately 380 nm for the ZnO thin film.

Investigation on V2O5 Thin Films Prepared by Spray Pyrolysis Technique

NASA Astrophysics Data System (ADS)

Anasthasiya, A. Nancy Anna; Gowtham, K.; Shruthi, R.; Pandeeswari, R.; Jeyaprakash, B. G.

The spray pyrolysis technique was employed to deposit V2O5 thin films on a glass substrate. By varying the precursor solution volume from 10mL to 50mL in steps of 10mL, films of various thicknesses were prepared. Orthorhombic polycrystalline V2O5 films were inferred from the XRD pattern irrespective of precursor solution volume. The micro-Raman studies suggested that annealed V2O5 thin film has good crystallinity. The effect of precursor solution volume on morphological and optical properties were analysed and reported.

Comparison of carrier transport mechanism under UV/Vis illumination in an AZO photodetector and an AZO/p-Si heterojunction photodiode produced by spray pyrolysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shasti, M.; Mortezaali, A., E-mail: mortezaali@alzahra.ac.ir; Dariani, R. S.

2015-01-14

In this study, Aluminum doped Zinc Oxide (AZO) layer is deposited on p-type silicon (p-Si) by spray pyrolysis method to fabricate ultraviolet-visible (UV/Vis) photodetector as Al doping process can have positive effect on the photodetector performance. Morphology, crystalline structure, and Al concentration of AZO layer are investigated by SEM, XRD, and EDX. The goal of this study is to analyze the mechanism of carrier transport by means of current-voltage characteristics under UV/Vis illumination in two cases: (a) electrodes connected to the surface of AZO layer and (b) electrodes connected to cross section of heterojunction (AZO/p-Si). Measurements indicate that the AZO/p-Simore » photodiode exhibits a higher photocurrent and lower photoresponse time under visible illumination with respect to AZO photodetector; while under UV illumination, the above result is inversed. Besides, the internal junction field of AZO/p-Si heterojunction plays an important role on this mechanism.« less

Compositional dependence of optical and electrical properties of indium doped zinc oxide (IZO) thin films deposited by chemical spray pyrolysis

NASA Astrophysics Data System (ADS)

Dintle, Lawrence K.; Luhanga, Pearson V. C.; Moditswe, Charles; Muiva, Cosmas M.

2018-05-01

The structural and optoelectronic properties of undoped and indium doped zinc oxide (IZO) thin films grown on glass substrates through a simple reproducible custom-made pneumatic chemical spray pyrolysis technique are presented. X-ray diffraction (XRD) results showed a polycrystalline structure of hexagonal wurtzite phase growing preferentially along the (002) plane for the undoped sample. Increase in dopant content modified the orientation leading to more pronounced (100) and (101) reflections. Optical transmission spectra showed high transmittance of 80-90% in the visible range for all thin films. The optical band gap energy (Eg) was evaluated on the basis of the derivative of transmittance (dT/dλ) versus wavelength (λ) model and Tauc's extrapolation method in the region where the absorption coefficient, α ≥ 104 cm-1. The observed values of Eg were found to decrease generally with increasing In dopant concentration. From the figure of merit calculations a sample with 4 at.% In dopant concentration showed better optoelectronic properties.

Custom-designed nanomaterial libraries for testing metal oxide toxicity

PubMed Central

Pokhrel, Suman; Nel, André E.; Mädler, Lutz

2014-01-01

Conspectus Advances in aerosol technology over the past 10 years have provided methods that enable the generation and design of ultrafine nanoscale materials for different applications. The particles are produced combusting a precursor solution and its chemical reaction in the in the gas phase. Flame spray pyrolysis (FSP) is a highly versatile technique for single step and scalable synthesis of nanoscale materials. New innovations in particle synthesis using FSP technology and its precursor chemistry have enabled flexible dry synthesis of loosely-agglomerated highly crystalline ultrafine powders (porosity ≥ 90%) of binary, ternary and mixed binary or ternary oxides. The flame spray pyrolysis lies at the intersection of combustion science, aerosols technology and materials chemistry. The interdisciplinary research is not only inevitable but is becoming increasingly crucial in the design of nanoparticles (NPs) made in the gas phase. The increasing demand especially in the bio-applications for particles with specific material composition, high purity and crystallinity can be often fulfilled with the fast, single step FSP technique. PMID:23194152

Transparent Conducting Mo-Doped CdO Thin Films by Spray Pyrolysis Method for Solar Cell Applications

NASA Astrophysics Data System (ADS)

Helen, S. J.; Devadason, Suganthi; Haris, M.; Mahalingam, T.

2018-04-01

Pure and 3%, 5%, and 7% molybdenum-doped cadmium oxide (CdO) thin films have been prepared on glass substrates preheated to 400°C using a spray pyrolysis technique, then analyzed using x-ray diffraction analysis, field-emission scanning electron microscopy, ultraviolet-visible spectroscopy, and photoluminescence and Hall measurements. The films were found to have polycrystalline nature with cubic structure. The crystallite size was calculated to be ˜ 12 nm for various doping concentrations. Doping improved the optical transparency of the CdO thin film, with the 5% Mo-doped film recording the highest transmittance in the optical region. The energy bandgap deduced from optical studies ranged from 2.38 eV and 2.44 eV for different Mo doping levels. The electrical conductivity was enhanced on Mo doping, with the highest conductivity of 1.74 × 103 (Ω cm)-1 being achieved for the 5% Mo-doped CdO thin film.

Influence of solution deposition rate on properties of V{sub 2}O{sub 5} thin films deposited by spray pyrolysis technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abd–Alghafour, N. M., E-mail: na2013bil@gmail.com; Ahmed, Naser M.; Hassan, Zai

Vanadium oxide (V{sub 2}O{sub 5}) thin films were deposited on glass substrates by using a cost-efficient spray pyrolysis technique. The films were grown at 350° through thermal decomposition of VCl{sub 3} in deionized water with different solution spray rates. The high resolution X-ray diffraction results revealed the formation of nanocrystalline films having orthorhombic structures with preferential orientation along (101) direction. The spray rate influenced the surface morphology and crystallite size of the films. The crystallite size was found to increase whereas the micro-strain was decreased by increasing the spray deposition rates. The increase in crystallite size and decrease in themore » macrostrain resulted in an improvement in the films’ crystallinity. The UV-Visible spectroscopy analysis indicated that the average transmittance of all films lies in the range 75-80 %. The band gap of V{sub 2}O{sub 5} film was decreased from 2.65 to 2.46 eV with increase of the spray deposition rate from 5 ml/min to 10 ml/min. first, second, and third level headings (first level heading).« less

Fabrication of Semiconducting Methylammonium Lead Halide Perovskite Particles by Spray Technology

NASA Astrophysics Data System (ADS)

Ahmadian-Yazdi, Mohammad-Reza; Eslamian, Morteza

2018-01-01

In this "nano idea" paper, three concepts for the preparation of methylammonium lead halide perovskite particles are proposed, discussed, and tested. The first idea is based on the wet chemistry preparation of the perovskite particles, through the addition of the perovskite precursor solution to an anti-solvent to facilitate the precipitation of the perovskite particles in the solution. The second idea is based on the milling of a blend of the perovskite precursors in the dry form, in order to allow for the conversion of the precursors to the perovskite particles. The third idea is based on the atomization of the perovskite solution by a spray nozzle, introducing the spray droplets into a hot wall reactor, so as to prepare perovskite particles, using the droplet-to-particle spray approach (spray pyrolysis). Preliminary results show that the spray technology is the most successful method for the preparation of impurity-free perovskite particles and perovskite paste to deposit perovskite thin films. As a proof of concept, a perovskite solar cell with the paste prepared by the sprayed perovskite powder was successfully fabricated.

Fabrication of Semiconducting Methylammonium Lead Halide Perovskite Particles by Spray Technology.

PubMed

Ahmadian-Yazdi, Mohammad-Reza; Eslamian, Morteza

2018-01-10

In this "nano idea" paper, three concepts for the preparation of methylammonium lead halide perovskite particles are proposed, discussed, and tested. The first idea is based on the wet chemistry preparation of the perovskite particles, through the addition of the perovskite precursor solution to an anti-solvent to facilitate the precipitation of the perovskite particles in the solution. The second idea is based on the milling of a blend of the perovskite precursors in the dry form, in order to allow for the conversion of the precursors to the perovskite particles. The third idea is based on the atomization of the perovskite solution by a spray nozzle, introducing the spray droplets into a hot wall reactor, so as to prepare perovskite particles, using the droplet-to-particle spray approach (spray pyrolysis). Preliminary results show that the spray technology is the most successful method for the preparation of impurity-free perovskite particles and perovskite paste to deposit perovskite thin films. As a proof of concept, a perovskite solar cell with the paste prepared by the sprayed perovskite powder was successfully fabricated.

Characterization and Electrochromic Properties of Vanadium Oxide Thin Films Prepared via Spray Pyrolysis

NASA Astrophysics Data System (ADS)

Mousavi, M.; Kompany, A.; Shahtahmasebi, N.; Bagheri-Mohagheghi, M.-M.

2013-08-01

Vanadium oxide thin films were grown on glass substrates using spray pyrolysis technique. The effects of substrate temperature, vanadium concentration in the initial solution and the solution spray rate on the nanostructural and the electrochromic properties of deposited films are investigated. Characterization and the electrochromic measurements were carried out using X-ray diffraction, scanning electron microscopy and cyclic voltammogram. XRD patterns showed that the prepared films have polycrystalline structure and are mostly mixed phases of orthorhombic α-V2O5 along with minor β-V2O5 and V4O9 tetragonal structures. The preferred orientation of the deposited films was found to be along [101] plane. The cyclic voltammogram results obtained for different samples showed that only the films with 0.2 M solution concentration, 5 ml/min solution spray rate and 450°C substrate temperature exhibit two-step electrochromic properties. The results show a correlation between cycle voltammogram, morphology and resistance of the films.

Superior Na-ion storage properties of high aspect ratio SnSe nanoplates prepared by a spray pyrolysis process

NASA Astrophysics Data System (ADS)

Park, Gi Dae; Lee, Jong-Heun; Kang, Yun Chan

2016-06-01

SnSe nanoplates with thin and uniform morphology are prepared by one-pot spray pyrolysis, and are examined as anode materials for Na-ion batteries. During the spray pyrolysis process, metallic Se and Sn are prepared from SeO2 and SnO2, respectively, under a reducing atmosphere. Metallic Sn and metalloid Se, with melting points of 232 and 221 °C, respectively, form a melted Sn-Se mixture, which reacts exothermally to form SnSe nanocrystals. Several of these nanocrystals are grown simultaneously forming a micron-sized powder. Complete elimination of the excess amount of metalloid Se, by forming H2Se gas, results in aggregation-free SnSe nanoplates. The aspect ratio of these nanoplates is as high as 11.3. The discharge capacities for the SnSe nanoplates, prepared from spray solutions containing 100, 400, and 800% of the stoichiometric SeO2 content needed to form SnSe, are 407, 558, and 211 mA h g-1, respectively, after 50 cycles at a constant current density of 0.3 A g-1 their capacity retentions calculated from the second cycle onwards are 77, 100, and 60%, respectively. The phase pure SnSe nanoplates with a high aspect ratio show good cycling and rate performances for Na-ion storage.SnSe nanoplates with thin and uniform morphology are prepared by one-pot spray pyrolysis, and are examined as anode materials for Na-ion batteries. During the spray pyrolysis process, metallic Se and Sn are prepared from SeO2 and SnO2, respectively, under a reducing atmosphere. Metallic Sn and metalloid Se, with melting points of 232 and 221 °C, respectively, form a melted Sn-Se mixture, which reacts exothermally to form SnSe nanocrystals. Several of these nanocrystals are grown simultaneously forming a micron-sized powder. Complete elimination of the excess amount of metalloid Se, by forming H2Se gas, results in aggregation-free SnSe nanoplates. The aspect ratio of these nanoplates is as high as 11.3. The discharge capacities for the SnSe nanoplates, prepared from spray solutions containing 100, 400, and 800% of the stoichiometric SeO2 content needed to form SnSe, are 407, 558, and 211 mA h g-1, respectively, after 50 cycles at a constant current density of 0.3 A g-1 their capacity retentions calculated from the second cycle onwards are 77, 100, and 60%, respectively. The phase pure SnSe nanoplates with a high aspect ratio show good cycling and rate performances for Na-ion storage. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr02983c

Metal sulfide thin films by chemical spray pyrolysis

NASA Astrophysics Data System (ADS)

Krunks, Malle; Mellikov, Enn

2001-04-01

CdS, ZnS and CuS thin films were prepared by spray pyrolysis method using metal chlorides and thiourea (tu) as starting materials. Metal sulfide films form as products of thermal decomposition of complexes Cd(tu)2Cl2, Zn(tu)2Cl2 and Cu(tu)Cl(DOT)1/2H2O, originally formed in aqueous solution at precursors molar ratio 1:2. The metal-ligand bonding is thermally stable up to 220 degrees Celsius, followed by multistep degradation process of complexes. The TG/DTA analysis show similar thermal behavior of complexes up to 300 degrees Celsius with the formation of metal sulfides in this decomposition step. In air intensive oxidation processes are detected close to 400, 600 and 720 degrees Celsius for Cu, Cd and Zn complexes, respectively. The results of thermoanalytical study and XRD of sprayed films show that CdS and ZnS films could be grown at 450 degrees Celsius even in air while deposition of copper sulfide films should be performed in an inert atmosphere. High total impurities content of 10 wt% in CdS films prepared at 240 degrees Celsius is originated from the precursor and reduced to 2 wt% by increasing the growth temperature up to 400 degrees Celsius.

Synthesis, characterization and ellipsometric study of ultrasonically sprayed Co3O4 films

NASA Astrophysics Data System (ADS)

Gençyılmaz, O.; Taşköprü, T.; Atay, F.; Akyüz, İ.

2015-10-01

In the present study, cobalt oxide (Co3O4) films were produced using ultrasonic spray pyrolysis technique onto the glass substrate at different temperatures (200-250-300-350 °C). The effect of substrate temperature on the structural, optical, surface and electrical properties of Co3O4 films was reported. Thickness, refractive index and extinction coefficient of the films were determined by spectroscopic ellipsometry, and X-ray diffraction analyses revealed that Co3O4 films were polycrystalline fcc structure and the substrate temperature significantly improved the crystal structure of Co3O4 films. The films deposited at 350 °C substrate temperature showed the best structural quality. Transmittance, absorbance and reflectance spectra were taken by means of UV-Vis spectrophotometer, and optical band gap values were calculated using optical method. Surface images and roughness values of the films were taken by atomic force microscopy to see the effect of deposition temperature on surface properties. The resistivity of the films slightly decreases with increase in the substrate temperature from 1.08 × 104 to 1.46 × 102 Ω cm. Finally, ultrasonic spray pyrolysis technique allowed production of Co3O4 films, which are alternative metal oxide film for technological applications, at low substrate temperature.

Uniform nanoparticles by flame-assisted spray pyrolysis (FASP) of low cost precursors

PubMed Central

Rudin, Thomas; Wegner, Karsten

2013-01-01

A new flame-assisted spray pyrolysis (FASP) reactor design is presented, which allows the use of inexpensive precursors and solvents (e.g., ethanol) for synthesis of nanoparticles (10–20 nm) with uniform characteristics. In this reactor design, a gas-assisted atomizer generates the precursor solution spray that is mixed and combusted with externally fed inexpensive fuel gases (acetylene or methane) at a defined height above the atomizing nozzle. The gaseous fuel feed can be varied to control the combustion enthalpy content of the flame and onset of particle formation. This way, the enthalpy density of the flame is decoupled from the precursor solution composition. Low enthalpy content precursor solutions are prone to synthesis of non-uniform particles (e.g., bimodal particle size distribution) by standard flame spray pyrolysis (FSP) processes. For example, metal nitrates in ethanol typically produce nanosized particles by gas-to-particle conversion along with larger particles by droplet-to-particle conversion. The present FASP design facilitates the use of such low enthalpy precursor solutions for synthesis of homogeneous nanopowders by increasing the combustion enthalpy density of the flame with low-cost, gaseous fuels. The effect of flame enthalpy density on product properties in the FASP configuration is explored by the example of Bi2O3 nanoparticles produced from bismuth nitrate in ethanol. Product powders were characterized by nitrogen adsorption, X-ray diffraction, X-ray disk centrifuge, and transmission electron microscopy. Homogeneous Bi2O3 nanopowders were produced both by increasing the gaseous fuel content and, most notably, by cutting the air entrainment prior to ignition of the spray. PMID:23408113

Microemulsion flame pyrolysis for hopcalite nanoparticle synthesis: a new concept for catalyst preparation.

PubMed

Biemelt, T; Wegner, K; Teichert, J; Kaskel, S

2015-04-07

A new route to highly active hopcalite catalysts via flame spray pyrolysis of an inverse microemulsion precursor is reported. The nitrate derived nanoparticles are around 15 nm in diameter and show excellent conversion of CO under ambient conditions, outperforming commercial reference hopcalite materials produced by co-precipitation.

Thin Film CuInS2 Prepared by Spray Pyrolysis with Single-Source Precursors

NASA Technical Reports Server (NTRS)

Jin, Michael H.; Banger, Kulinder K.; Harris, Jerry D.; Cowen, Jonathan E.; Hepp, Aloysius F.; Lyons, Valerie (Technical Monitor)

2002-01-01

Both horizontal hot-wall and vertical cold-wall atmospheric chemical spray pyrolysis processes deposited near single-phase stoichiometric CuInS2 thin films. Single-source precursors developed for ternary chalcopyrite materials were used for this study, and a new liquid phase single-source precursor was tested with a vertical cold-wall reactor. The depositions were carried out under an argon atmosphere, and the substrate temperature was kept at 400 C. Columnar grain structure was obtained with vapor deposition, and the granular structure was obtained with (liquid) droplet deposition. Conductive films were deposited with planar electrical resistivities ranging from 1 to 30 Omega x cm.

Low Temperature Synthesis of Fluorine-Doped Tin Oxide Transparent Conducting Thin Film by Spray Pyrolysis Deposition.

PubMed

Ko, Eun-Byul; Choi, Jae-Seok; Jung, Hyunsung; Choi, Sung-Churl; Kim, Chang-Yeoul

2016-02-01

Transparent conducting oxide (TCO) is widely used for the application of flat panel display like liquid crystal displays and plasma display panel. It is also applied in the field of touch panel, solar cell electrode, low-emissivity glass, defrost window, and anti-static material. Fluorine-doped tin oxide (FTO) thin films were fabricated by spray pyrolysis of ethanol-added FTO precursor solutions. FTO thin film by spray pyrolysis is very much investigated and normally formed at high temperature, about 500 degrees C. However, these days, flexible electronics draw many attentions in the field of IT industry and the research for flexible transparent conducting thin film is also required. In the industrial field, indium-tin oxide (ITO) film on polymer substrate is widely used for touch panel and displays. In this study, we investigated the possibility of FTO thin film formation at relatively low temperature of 250 degrees C. We found out that the control of volume of input precursor and exhaust gases could make it possible to form FTO thin film with a relatively low electrical resistance, less than 100 Ohm/sq and high optical transmittance about 88%.

Preparation of mesoporous alumina particles by spray pyrolysis and application to double bond migration of 2-butene.

PubMed

Song, Ki Chang; Kim, Joo Hyun; Kim, Jin Han; Jung, Kyeong Youl; Park, Young-Kwon; Jeon, Jong-Ki

2011-07-01

The objective of the present study is to investigate the catalytic performance of mesoporous alumina that were prepared via spray pyrolysis for double bond migration from 2-butene to 1-butene. The mesoporous alumina particles were prepared via spray pyrolysis by changing the types of organic surfactants and Al precursors. The texture and acidic properties of mesoporous alumina were analyzed through N2 adsorption, SEM, ammonia-temperature programmed desorption, and FT-IR of adsorbed pyridine. The morphologies and texture properties of the mesoporous alumina were found to have been strongly influenced by the combination of the Al precursor and the structure-directing agents. The mesoporous alumina samples had two kinds of acidic sites: a Lewis acid site and a H-bonded weak acid site. 1-Butene was produced selectively through double bond migration of 2-butene over all of the mesoporous alumina catalysts. The catalyst prepared by using a chloride compound as an aluminium precursor and CTAC as a structure-directing agent showed the highest activity in the double bond migration of 2-butene, which was attributed to its large surface area and an overall high amount of acid sites.

Autonomous micromotor based on catalytically pneumatic behavior of balloon-like MnO(x)-graphene crumples.

PubMed

Chen, Xueli; Wu, Guan; Lan, Tian; Chen, Wei

2014-07-11

A novel autonomous micromotor, based on catalytically pneumatic behaviour of balloon-like MnOx-graphene crumples, has been synthesized via an ultrasonic spray pyrolysis method. Through catalytic decomposition of H2O2 into O2, the gas accumulated in a confined space and was released to generate a strong force to push the micromotor.

Fabrication of functional nanomaterials using flame assisted spray pyrolysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Purwanto, Agus, E-mail: aguspur@uns.ac.id

2014-02-24

Flame assisted spray pyrolysis (FASP) is a class of synthesis method for nanomaterials fabrication. The ability to control nanomaterials characteristics and easy to be-scaled up are the main features of FASP. The crystallinity and particles size of the prepared nanomaterials can be easily controlled by variation of fuel flow rate. The precursor concentration, carrier gas flow rate, and carrier gas can be also used to control the prepared nanomaterials. Energy related nanomaterials preparation uses as the example case in FASP application. These material are yttrium aluminum garnet (YAG:Ce) and tungsten oxide (WO{sub 3}). It needs strategies to produce these materialsmore » into nano-sized order. YAG:Ce nanoparticles only can be synthesized by FASP using the urea addition. The decomposition of urea under high temperature of flame promotes the breakage of YAG:Ce particles into nanoparticles. In the preparation of WO{sub 3}, the high temperature flame can be used to gasify WO{sub 3} solid material. As a result, WO{sub 3} nanoparticles can be prepared easily. Generally, to produce nanoparticles via FASP method, the boiling point of the material is important to determine the strategy which will be used.« less

Effects of ultraviolet light on B-doped CdS thin films prepared by spray pyrolysis method using perfume atomizer

NASA Astrophysics Data System (ADS)

Novruzov, V. D.; Keskenler, E. F.; Tomakin, M.; Kahraman, S.; Gorur, O.

2013-09-01

Boron doped CdS thin films were deposited by spray pyrolysis method using perfume atomizer. The effects of ultraviolet light on the structural, optical and electrical properties of B-doped CdS thin films were investigated as a function of dopant concentration (B/Cd). X-ray diffraction studies showed that all samples were polycrystalline nature with hexagonal structure. It was determined that the preferred orientation of non-illuminated samples changes from (1 0 1) to (0 0 2) with B concentration. The c lattice constant of films decreases from 6.810 Å to 6.661 Å with boron doping. The XRD peak intensity increased with the illumination for almost all the samples. The lattice parameters of B-doped samples remained nearly constant after illumination. It was found that the optical transmittance, photoluminescence spectra, resistivity and carrier concentration of the B-doped samples are stable after the illumination with UV light. Also the effects of UV light on B-doped CdS/Cu2S solar cell were investigated and it was determined that photoelectrical parameters of B-doped solar cell were more durable against the UV light.

Effect of the substrate temperature on the physical properties of molybdenum tri-oxide thin films obtained through the spray pyrolysis technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martinez, H.M.; Torres, J., E-mail: njtorress@unal.edu.co; Lopez Carreno, L.D.

2013-01-15

Polycrystalline molybdenum tri-oxide thin films were prepared using the spray pyrolysis technique; a 0.1 M solution of ammonium molybdate tetra-hydrated was used as a precursor. The samples were prepared on Corning glass substrates maintained at temperatures ranging between 423 and 673 K. The samples were characterized through micro Raman, X-ray diffraction, optical transmittance and DC electrical conductivity. The species MoO{sub 3} (H{sub 2}O){sub 2} was found in the sample prepared at a substrate temperature of 423 K. As the substrate temperature rises, the water disappears and the samples crystallize into {alpha}-MoO{sub 3}. The optical gap diminishes as the substrate temperaturemore » rises. Two electrical transport mechanisms were found: hopping under 200 K and intrinsic conduction over 200 K. The MoO{sub 3} films' sensitivity was analyzed for CO and H{sub 2}O in the temperature range 160 to 360 K; the results indicate that CO and H{sub 2}O have a reduction character. In all cases, it was found that the sensitivity to CO is lower than that to H{sub 2}O. - Highlights: Black-Right-Pointing-Pointer A low cost technique is used which produces good material. Black-Right-Pointing-Pointer Thin films are prepared using ammonium molybdate tetra hydrated. Black-Right-Pointing-Pointer The control of the physical properties of the samples could be done. Black-Right-Pointing-Pointer A calculation method is proposed to determine the material optical properties. Black-Right-Pointing-Pointer The MoO{sub 3} thin films prepared by spray pyrolysis could be used as gas sensor.« less

Phase transition studies in bismuth ferrite thin films synthesized via spray pyrolysis technique

NASA Astrophysics Data System (ADS)

Goyal, Ankit; Lakhotia, Harish

2013-06-01

Multiferroic are the materials, which combine two or more "ferroic" properties, ferromagnetism, ferroelectricity or ferroelasticity. BiFeO3 is the only single phase multiferroic material which possesses a high Curie temperature (TC ˜ 1103 K), and a high Neel temperature (TN ˜ 643 K) at room temperature. Normally sophisticated methods are being used to deposit thin films but here we have tried a different method Low cost Spray Pyrolysis Method to deposit BiFeO3 thin film of Glass Substrate with rhombohedral crystal structure and R3c space group. Bismuth Ferrite thin films are synthesized using Bismuth Nitrate and Iron Nitrate as precursor solutions. X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) were used to study structural analysis of prepared thin films. XRD pattern shows phase formation of BiFeO3 and SEM analysis shows formation of nanocrystals of 200 nm. High Temperature Resistivity measurements were done by using Keithley Electrometer (Two Probe system). Abrupt behavior in temperature range (313 K - 400K) has been observed in resistance studies which more likely suggests that in this transition the structure is tetragonal rather than rhombohedral. BiFeO3 is the potential active material in the next generation of ferroelectric memory devices.

Spray pyrolysis synthesized Cu(In,Al)(S,Se)2 thin films solar cells

NASA Astrophysics Data System (ADS)

Aamir Hassan, Muhammad; Mujahid, Mohammad; Woei, Leow Shin; Wong, Lydia Helena

2018-03-01

Cu(In,Al)(S,Se)2 thin films are prepared by the Spray pyrolysis of aqueous precursor solutions of copper, indium, aluminium and sulphur sources. The bandgap of the films was engineered by aluminium (Al) doping in CISSe films deposited on molybdenum (Mo) coated glass substrate. The as-sprayed thin films were selenized at 500 °C for 10 min. Cadmium sulphide (CdS) buffer layer was deposited by chemical bath deposition process. Solar cell devices were fabricated with configuration of glass/Mo/CIASSe/CdS/i-ZnO/AZO. The solar cell device containing thin film of Cu(In,Al)(S,Se)2 with our optimized composition shows j-V characteristics of Voc = 0.47 V, jsc = 21.19 mA cm-2, FF = 52.88% and power conversion efficiency of 5.27%, under AM 1.5, 100 mW cm-2 illumination.

Transparent and conducting ZnO films grown by spray pyrolysis

NASA Astrophysics Data System (ADS)

Hadjeris, Lazhar; Herissi, Labidi; Badreddine Assouar, M.; Easwarakhanthan, Thomas; Bougdira, Jamal; Attaf, Nadhir; Salah Aida, M.

2009-03-01

ZnO films were prepared using the simple, flexible and cost-effective spray pyrolysis technique at different substrate temperatures and precursor molarity values. The films' structural, optical and electrical properties were investigated by x-ray diffraction, UV-VIS transmittance spectroscopy, profilometry and voltage-current-temperature (VIT) measurements. The films prepared at substrate temperatures above 400 °C appear better crystallized with (0 0 2) preferred orientation and exhibit higher visible transmittance (65-80%), higher electrical n-type semiconductor conductivity (10-50 (Ω cm)-1), lower activation energy (<0.35 eV) and smaller Urbach energy (80 meV). These results indicate that such sprayed ZnO films are chemically purer and have many fewer defects and less disorder owing to an almost complete chemical decomposition of the precursor droplets. ZnO films having desired optical and electrical properties for cheaper large-area solar cells may thus be tailored through the substrate temperature and the precursor molarity.

Transparent heaters made by ultrasonic spray pyrolysis of SnO2 on soda-lime glass substrates

NASA Astrophysics Data System (ADS)

Ansari, Mohammad; Akbari-Saatloo, Mehdi; Gharesi, Mohsen

2017-12-01

Transparent heaters have become important owing to the increasing demand in automotive and display device manufacturing industries. Indium tin oxide (ITO) is the most commonly used material for production of transparent heaters, but the fabrication cost is high as the indium resources are diminishing fast. This has been the driving force behind the intense research for discovering more durable and cost-effective alternatives. Tin oxide, with its high temperature stability and coexisting high levels of conductivity and transparency, can replace expensive ITO in the fabrication of transparent heaters. Here, we propose tin oxide films deposited using ultrasonic spray pyrolysis as the raw material for the fabrication of transparent heaters. Silver contacts are paste printed on the deposited SnO2 layers, which provide the necessary connections to the external circuitry. Deposition of films having sheet resistance in the 150 Ω/□ range takes only ∼5 minutes and the utilized methods are fully scalable to mass production level. Durability tests, carried out for weeks of continuous operation at different elevated temperatures, demonstrated the long load life of the produced heaters.

Properties of NiO thin films deposited by intermittent spray pyrolysis process

NASA Astrophysics Data System (ADS)

Reguig, B. A.; Khelil, A.; Cattin, L.; Morsli, M.; Bernède, J. C.

2007-02-01

NiO thin films have been grown on glass substrates by intermittent spray pyrolysis deposition of NiCl 2·6H 2O diluted in distilled water, using a simple "perfume atomizer". The effect of the solution molarity on their properties was studied and compared to those of NiO thin films deposited with a classical spray system. It is shown that NiO thin films crystallized in the NiO structure are achieved after deposition. Whatever the precursor molarity, the grain size is around 25-30 nm. The crystallites are preferentially oriented along the (1 1 1) direction. All the films are p-type. However, the thickness and the conductivity of the NiO films depend on the precursor contraction. By comparison with the properties of films deposited by classical spray technique, it is shown that the critical precursor concentration, which induces strong thin films properties perturbations, is higher when a perfume atomizer is used. This broader stability domain can be attributed to better chlorides decomposition during the rest time used in the perfume atomizer technique.

Effect of boric acid on the properties of Li{sub 2}MnO{sub 3}·LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} composite cathode powders prepared by large-scale spray pyrolysis with droplet classifier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hong, Young Jun; Choi, Seung Ho; Sim, Chul Min

2012-12-15

Graphical abstract: Display Omitted Highlights: ► Spherical shape Li{sub 2}MnO{sub 3}·LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} composite cathode powders are prepared by large-scale spray pyrolysis with droplet classifier. ► Boric acid improves the morphological and electrochemical properties of the composite cathode powders. ► The discharge capacity of the composite cathode powders decreases from 217 to 196 mAh g{sup −1} by the 30th cycle. -- Abstract: Spherically shaped 0.3Li{sub 2}MnO{sub 3}·0.7LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} composite cathode powders with filled morphology and narrow size distribution are prepared by large-scale spray pyrolysis. A droplet classification reduces the standard deviation of the size distribution of themore » composite cathode powders. Addition of boric acid improves the morphological properties of the product powders by forming a lithium borate glass material with low melting temperature. The optimum amount of boric acid dissolved in the spray solution is 0.8 wt% of the composite powders. The powders prepared from the spray solution with 0.8 wt% boric acid have a mixed layered crystal structure comprising Li{sub 2}MnO{sub 3} and LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} phases, thus forming a composite compound. The initial charge and discharge capacities of the composite cathode powders prepared from the 0.8 wt% boric acid spray solution are 297 and 217 mAh g{sup −1}, respectively. The discharge capacity of the powders decreases from 217 to 196 mAh g{sup −1} by the 30th cycle, in which the capacity retention is 90%.« less

Preparation of low cost n-ZnO/MgO/p-Si heterojunction photodetector by laser ablation in liquid and spray pyrolysis

NASA Astrophysics Data System (ADS)

Ismail, Raid A.; Khashan, Khawla S.; Jawad, Muslim F.; Mousa, Ali M.; Mahdi, Farah

2018-05-01

In this study, low cost ZnO/Si and ZnO/MgO/Si heterojunction (HJ) photodetectors were fabricated using laser ablation and spray Pyrolysis techniques. MgO nanofibers were synthesized by laser ablation of Mg target in distilled water. Also; the ZnO films were prepared by spray pyrolysis technique. The optical and structural properties of nanostructured MgO were investigated using XRD, SEM and FT-IR. The XRD results showed that the MgO was polycrystalline with cubic structure. SEM investigation confirmed the formation of MgO nanofibers and sub-microparticles. The optical energy gaps of MgO and ZnO were calculated and found to be 5.7 eV and 3.3 eV, respectively. For the electrical properties; responsivity, quantum efficiency, specific detectivity, and speed of response of the photodetector were measured and found to enhance after the insertion of nanostructured MgO film. The Photoresponse results at 3 V reverse bias showed that the maximum responsivity of ZnO/Si and ZnO/MgO/Si photodetectors were 185 and 331 mAW‑1 at 500 nm, respectively. The specific detectivity of ZnO/MgO/Si Photodetector was higher than that of ZnO/Si.

Macro controlling of copper oxide deposition processes and spray mode by using home-made fully computerized spray pyrolysis system

NASA Astrophysics Data System (ADS)

Essa, Mohammed Sh.; Chiad, Bahaa T.; Shafeeq, Omer Sh.

2017-09-01

Thin Films of Copper Oxide (CuO) absorption layer have been deposited using home-made Fully Computerized Spray Pyrolysis Deposition system FCSPD on glass substrates, at the nozzle to substrate distance equal to 20,35 cm, and computerized spray mode (continues spray, macro-control spray). The substrate temperature has been kept at 450 °c with the optional user can enter temperature tolerance values ± 5 °C. Also that fixed molar concentration of 0.1 M, and 2D platform speed or deposition platform speed of 4mm/s. more than 1000 instruction program code, and specific design of graphical user interface GUI to fully control the deposition process and real-time monitoring and controlling the deposition temperature at every 200 ms. The changing in the temperature has been recorded during deposition processes, in addition to all deposition parameters. The films have been characterized to evaluate the thermal distribution over the X, Y movable hot plate, the structure and optical energy gap, thermal and temperature distribution exhibited a good and uniform distribution over 20 cm2 hot plate area, X-ray diffraction (XRD) measurement revealed that the films are polycrystalline in nature and can be assigned to monoclinic CuO structure. Optical band gap varies from 1.5-1.66 eV depending on deposition parameter.

Properties of transparent conducting tin monoxide(SnO) thin films prepared by chemical spray pyrolysis method

NASA Astrophysics Data System (ADS)

Eqbal, Ebitha; Anila, E. I.

2018-01-01

Transparent conducting Stannous Oxide (SnO) thin films were obtained by chemical spray pyrolysis method on glass substrates for 0.1 M and 0.25 M concentration of precursor solutions. Their structural, morphological, optical and electrical properties were investigated. X-ray diffraction (XRD) study shows polycrystalline nature of the films with orthorhombic crystal structure. The morphological analysis was carried out by Scanning electron microscopy (SEM) and elemental analysis was done by Energy dispersive X-ray spectroscopy (EDX). The band gap of 0.1 M and 0.25 M thin film samples were found to be 3.58eV with 82% transmission and 3 eV with 30% transmission respectively. The film thickness, refractive index (n) and extinction coefficient (k) of the films were obtained by ellipsometric technique. Hall effect measurements reveal p-type conduction with mobility 7.8 cm2V-1s-1 and 15 cm2V-1s-1 and conductivity of 8.5 S/cm and 17.1 S/cm respectively for the 0.1 M and 0.25 M samples. Photoluminescence (PL) spectrum of the samples show a broad emission which covers near band edge (NBE) as well as deep level emission (DLE) in the region 380 nm-620 nm.

Correlation between fabrication factor and superconducting properties of the Tl-and-Bi-based high-Tc superconductor

NASA Technical Reports Server (NTRS)

Maki, Naoki; Okada, Michiya; Doi, Toshiya J.; Kanai, Tsuneyuki; Sato, Junichi; Higashiyama, Kazutoshi

1995-01-01

Large critical current densities (J(sub c)) were obtained in c axis oriented Tl-1 223/Ag composite tapes fabricated by spraying methods without a vacuum. Transport measurements at 77K under a zero field indicated a J(sub c) of 9 x 10(exp 4) A/sq cm and 7 x 10(exp 3) A/sq cm at 1T for the tapes fabricated by spray pyrolysis. The novel GPM method was also applied for Bi-2212/Ag PIT composite wire, and found to be very effective for improving the distribution of voids, which caused from the melt-solidifying process. The GPM showed a marked effect for obtaining homogeneous long wire. A 1 T class coil was successfully fabricated with monocore wire.

Morphology-controllable of Sn doped ZnO nanorods prepared by spray pyrolysis for transparent electrode application

NASA Astrophysics Data System (ADS)

Hameed, M. Shahul; Princice, J. Joseph; Babu, N. Ramesh; Zahirullah, S. Syed; Deshmukh, Sampat G.; Arunachalam, A.

2018-05-01

Transparent conductive Sn doped ZnO nanorods have been deposited at various doping level by spray pyrolysis technique on glass substrate. The structural, surface morphological and optical properties of these films have been investigated with the help of X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscope (AFM) and UV-Vis spectrophotometer respectively. XRD patterns revealed a successful high quality growth of single crystal ZnO nanorods with hexagonal wurtzite structure having (002) preferred orientation. The scanning electron microscope (SEM) image of the prepared films exposed the uniform distribution of Sn doped ZnO nanorod shaped grains. All these films were highly transparent in the visible region with average transmittance of 90%.

Synthesis of Single Crystalline ZnO Nanoparticles by Salt-Assisted Spray Pyrolysis

NASA Astrophysics Data System (ADS)

Panatarani, Camellia; Lenggoro, I. Wuled; Okuyama, Kikuo

2003-04-01

LiNO3 was used as a shield in the preparation of single crystalline ZnO particles by a spray pyrolysis process in order to prevent agglomeration and enhance the crystallinity of the ZnO. LiNO3 was added to a precursor solution of zinc acetate dihydrate prior to its atomization by means of an ultrasonic transducer. Agglomerate-free particles having a mean particle size of 26 nm were successfully obtained after washing the product. X-ray diffractometry, field-emission scanning electron micrograph and transmission electron micrograph data indicate that the size and morphology of ZnO were strongly influenced by the operating temperature used and the residence time of the particle in the reactor.

Structural, electrical and photovoltaic properties of CoS/Si heterojunction prepared by spray pyrolysis

NASA Astrophysics Data System (ADS)

El Radaf, I. M.; Nasr, Mahmoud; Mansour, A. M.

2018-01-01

Au/p-CoS/n-Si/Al heterojunction device was fabricated by spray pyrolysis technique. The structural and morphological features were examined by x-ray diffraction, scanning electron microscope and energy dispersive x-ray analysis. The capacitance-voltage characteristics of the prepared heterojunction were analyzed at room temperature in the dark. The current-voltage characteristics were examined under dark and different incident light intensities 20-100 mW cm-2. The rectification ratio, series resistance, shunt resistance, diode ideality factor and the effective barrier height were determined at dark and illumination conditions. The photovoltaic parameters such as short circuit current density, open circuit voltage, fill factor and power conversion efficiency were calculated at different incident light intensities.

The Effect of Film Composition on the Texture and Grain Size of CuInS2 Prepared by Spray Pyrolysis

NASA Technical Reports Server (NTRS)

Jin, Michael H.-C.; Banger, Kulbinder K.; Harris, Jerry D.; Hepp, Aloysius F.

2003-01-01

CuInS2 was deposited by spray pyrolysis using single-source precursors synthesized in-house. Films with either (112) or (204/220) preferred orientation always showed Cu-rich and In-rich composition respectively. The In-rich (204/220)-oriented films always contained a secondary phase evaluated as an In-rich compound, and the hindrance of (112)-oriented grain growth was confirmed by glancing angle X-ray diffraction. In conclusion, only the Cu-rich (112)-oriented films with dense columnar grains can be prepared without the secondary In-rich compound. The effect of extra Cu on the grain size and the solar cell results will be also presented.

Influence of vacuum annealing on the properties of Cu2SnS3 thin films using low cost ultrasonic spray pyrolysis

NASA Astrophysics Data System (ADS)

Rahaman, Sabina; Sunil, M. Anantha; Shaik, Habibuddin; Ghosh, Kaustab

2018-05-01

Deposition of Cu2SnS3 (CTS) thin films is successfully carried out on soda lime glass substrate using low cost ultrasonic spray pyrolysis technique. Vacuum annealing of CTS films is carried out at different temperatures 350°C, 400°C and 450°C. The present work is to study the effect of annealing temperature on the crystal structure, surface morphology and optical properties of CTS thin films. Structural studies confirm the formation of CTS phase. Raman analysis is carried out to study presence of defects with annealing temperature. Optical studies confirm that film prepared at 450°C temperature is suitable as absorber material for photovoltaic applications.

Quantum-dot-sensitized solar cells fabricated by the combined process of the direct attachment of colloidal CdSe quantum dots having a ZnS glue layer and spray pyrolysis deposition.

PubMed

Im, Sang Hyuk; Lee, Yong Hui; Seok, Sang Il; Kim, Sung Woo; Kim, Sang-Wook

2010-12-07

We were able to attach CdSe quantum dots (QDs) having a ZnS inorganic glue layer directly to a mesoporous TiO(2) (mp-TiO(2)) surface by spray coating and thermal annealing. Quantum-dot-sensitized solar cells based on CdSe QDs having ZnS as the inorganic glue layer could easily transport generated charge carriers because of the intimate bonding between CdSe and mp-TiO(2). The application of spray pyrolysis deposition (SPD) to obtain additional CdSe layers improved the performance characteristics to V(oc) = 0.45 V, J(sc) = 10.7 mA/cm(2), fill factor = 35.8%, and power conversion efficiency = 1.7%. Furthermore, ZnS post-treatment improved the device performance to V(oc) = 0.57 V, J(sc) = 11.2 mA/cm(2), fill factor = 35.4%, and power conversion efficiency = 2.2%.

Electrical Characteristics and Preparation of Nanostructured Pb(Zr0.5Ti0.5)O3 Films by Spray Pyrolysis

NASA Astrophysics Data System (ADS)

Koo, Horng-Show; Chen, Mi; Hotta, Yoichi; Kawai, Tomoji

2007-07-01

Nanostructured thin films of Pb(Zr0.5Ti0.5)O3 on Pt (1000 Å)/Ti (100 Å)/SiO2 (2000 Å)/Si substrates are prepared by spray pyrolysis and subsequently rapid thermal annealing. Lead nitrate, zirconium nitrate and titanium isopropoxide are used as starting material with ethylene glycol as solvent. The crystal structure of the as-sprayed films are transformed from the amorphous, pyrochlore and multiple phases of pyrochlore and perovskite to the single phase of perovskite as the annealing temperature is increased up to 500 °C. For the formation of single phase perovskite, excess lead of 10 mol % is required to compensate the loss of lead during the processing of the primitive films. The physical characteristics of the resultant films show the dielectric constant (\\varepsilonr) of 400, remanent polarization (2Pr) of 30.0 μC/cm2 and coercive field (2Ec) of 70.0 kV/cm, respectively.

Electrical Characteristics and Preparation of (Ba0.5Sr0.5)TiO3 Films by Spray Pyrolysis and Rapid Thermal Annealing

NASA Astrophysics Data System (ADS)

Koo, Horng-Show; Chen, Mi; Ku, Hong-Kou; Kawai, Tomoji

2007-04-01

Functional films of (Ba0.5Sr0.5)TiO3 on Pt (1000 Å)/Ti (100 Å)/SiO2 (2000 Å)/Si substrates are prepared by spray pyrolysis and subsequently rapid thermal annealing. Barium nitrate, strontium nitrate and titanium isopropoxide are used as starting materials with ethylene glycol as solvent. For (Ba0.5Sr0.5)TiO3 functional thin film, thermal characteristics of the precursor powder scratched from as-sprayed films show a remarkable peak around 300-400 °C and 57.7% weight loss up to 1000 °C. The as-sprayed precursor film with coffee-like color and amorphous-like phase is transformed into the resultant film with white, crystalline perovskite phase and characteristic peaks (110) and (100). The resultant films show correspondent increases of dielectric constant, leakage current and dissipation factor with increasing annealing temperatures. The dielectric constant is 264 and tangent loss is 0.21 in the resultant films annealed at 750 °C for 5 min while leakage current density is 1.5× 10-6 A/cm2 in the film annealed at 550 °C for 5 min.

Formation of CuAlO2 Film by Ultrasonic Spray Pyrolysis

NASA Astrophysics Data System (ADS)

Iping, S.; Lockman, Zainovia; Hutagalung, S. D.; Kamsul, A.; Matsuda, Atsunori

2011-10-01

Smooth, crack free and homogenous CuAlO2 film was produced by chemical solution deposition process via spray pyrolysis technique on a cleaned Si substrate. The precursor solution used was comprised of a mixture of 45.87 mmol Cu(NO3)2.3H2O and 90 mmol Al(NO3)3.9H2O at ratio of Cu:Al = 1.2:1. The precursor solution was placed in a mist chamber and was atomized by a nebulizer to produce precursor mist. The precursor mist was then carried out by Ar gas and was sprayed onto a heated Si. Two main parameters were studied: the distance between the nozzle of the precursor mist chamber and the Si and the temperature of the Si substrate. It appears that from the XRD data, CuAlO2 can be detected for samples prepared by spraying the precursor mist at temperature of > 550 °C with distance between the nozzle and the substrate of 3cm. Reaction of the Cu and Al ions in the mist near the substrate may have promoted the crystallisation of CuAlO2.

Delicate Structural Control of Si-SiOx-C Composite via High-Speed Spray Pyrolysis for Li-Ion Battery Anodes.

PubMed

Lee, Seung Jong; Kim, Hye Jin; Hwang, Tae Hoon; Choi, Sunghun; Park, Sung Hyeon; Deniz, Erhan; Jung, Dae Soo; Choi, Jang Wook

2017-03-08

Despite the high theoretical capacity, silicon (Si) anodes in lithium-ion batteries have difficulty in meeting the commercial standards in various aspects. In particular, the huge volume change of Si makes it very challenging to simultaneously achieve high initial Coulombic efficiency (ICE) and long-term cycle life. Herein, we report spray pyrolysis to prepare Si-SiO x composite using an aqueous precursor solution containing Si nanoparticles, citric acid, and sodium hydroxide (NaOH). In the precursor solution, Si nanoparticles are etched by NaOH with the production of [SiO 4 ] 4- . During the dynamic course of spray pyrolysis, [SiO 4 ] 4- transforms to SiO x matrix and citric acid decomposes to carbon surface layer with the assistance of NaOH that serves as a decomposition catalyst. As a result, a Si-SiO x composite, in which Si nanodomains are homogeneously embedded in the SiO x matrix with carbon surface layer, is generated by a one-pot process with a residence time of only 3.5 s in a flow reactor. The optimal composite structure in terms of Si domain size and Si-to-O ratio exhibited excellent electrochemical performance, such as reversible capacity of 1561.9 mAh g -1 at 0.06C rate and ICE of 80.2% and 87.9% capacity retention after 100 cycles at 1C rate.

One-Pot Synthesis of CoSex -rGO Composite Powders by Spray Pyrolysis and Their Application as Anode Material for Sodium-Ion Batteries.

PubMed

Park, Gi Dae; Kang, Yun Chan

2016-03-14

A simple one-pot synthesis of metal selenide/reduced graphene oxide (rGO) composite powders for application as anode materials in sodium-ion batteries was developed. The detailed mechanism of formation of the CoSe(x)-rGO composite powders that were selected as the first target material in the spray pyrolysis process was studied. The crumple-structured CoSe(x)-rGO composite powders prepared by spray pyrolysis at 800 °C had a crystal structure consisting mainly of Co0.85 Se with a minor phase of CoSe2. The bare CoSe(x) powders prepared for comparison had a spherical shape and hollow structure. The discharge capacities of the CoSe(x)-rGO composite and bare CoSe(x) powders in the 50th cycle at a constant current density of 0.3 A g(-1) were 420 and 215 mA h g(-1), respectively, and their capacity retentions measured from the second cycle were 80 and 46%, respectively. The high structural stability of the CoSe(x)-rGO composite powders for repeated sodium-ion charge and discharge processes resulted in superior sodium-ion storage properties compared to those of the bare CoSe(x) powders. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An investigation on the In doping of ZnO thin films by spray pyrolysis

NASA Astrophysics Data System (ADS)

Mahesh, Devika; Kumar, M. C. Santhosh

2018-04-01

Indium doped zinc oxide (IGZO)thin films are gaining much interest owing to its commercial application as transparent conductive oxide thin films. In the current study thin films indium doped ZnO thin films have been deposited on glass substrates by chemical spray pyrolysis technique with an indium concentration of 1, 2.5 and 4% in Zinc source. The films show a peak shift in the X-Ray Diffraction patterns with varying indium doping concentration. The (101) peak was enhanced for the 2.5 % indium doped films and variation in grain size with the different doping levels was studied. The as-deposited films are uniform and shown high transparency (>90%) in the visible region. Average thicknesses of films are found to be 800nm, calculated using the envelope method. The film with 2.5 % of indium content was found to be highly conducting than the rest, since for the lower and higher concentrations the conductivity was possibly halted by the limit in carrier concentration and indium segregation in the grain boundaries respectively. The enhancement of mobility and carrier concentration was clearly seen in the optimum films.

Selectivity Enhancement by Using Double-Layer MOX-Based Gas Sensors Prepared by Flame Spray Pyrolysis (FSP).

PubMed

Rebholz, Julia; Grossmann, Katharina; Pham, David; Pokhrel, Suman; Mädler, Lutz; Weimar, Udo; Barsan, Nicolae

2016-09-06

Here we present a novel concept for the selective recognition of different target gases with a multilayer semiconducting metal oxide (SMOX)-based sensor device. Direct current (DC) electrical resistance measurements were performed during exposure to CO and ethanol as single gases and mixtures of highly porous metal oxide double- and single-layer sensors obtained by flame spray pyrolysis. The results show that the calculated resistance ratios of the single- and double-layer sensors are a good indicator for the presence of specific gases in the atmosphere, and can constitute some building blocks for the development of chemical logic devices. Due to the inherent lack of selectivity of SMOX-based gas sensors, such devices could be especially relevant for domestic applications.

Selectivity Enhancement by Using Double-Layer MOX-Based Gas Sensors Prepared by Flame Spray Pyrolysis (FSP)

PubMed Central

Rebholz, Julia; Grossmann, Katharina; Pham, David; Pokhrel, Suman; Mädler, Lutz; Weimar, Udo; Barsan, Nicolae

2016-01-01

Here we present a novel concept for the selective recognition of different target gases with a multilayer semiconducting metal oxide (SMOX)-based sensor device. Direct current (DC) electrical resistance measurements were performed during exposure to CO and ethanol as single gases and mixtures of highly porous metal oxide double- and single-layer sensors obtained by flame spray pyrolysis. The results show that the calculated resistance ratios of the single- and double-layer sensors are a good indicator for the presence of specific gases in the atmosphere, and can constitute some building blocks for the development of chemical logic devices. Due to the inherent lack of selectivity of SMOX-based gas sensors, such devices could be especially relevant for domestic applications. PMID:27608028

Growth and characterization of V2O5 nanorods deposited by spray pyrolysis at low temperatures

NASA Astrophysics Data System (ADS)

Abd-Alghafour, N. M.; Ahmed, Naser M.; Hassan, Zai.; Mohammad, Sabah M.; Bououdina, M.

2016-07-01

Vanadium pentoxide (V2O5) nanorods were deposited by spray pyrolysis on preheated glass substrates at low temperatures. The influence of substrate temperature on the crystallization of V2O5 has been investigated. X-ray diffraction analysis (XRD) revealed that the films deposited at Tsub = 300°C were orthorhombic structures with preferential along (001) direction. Formation of nanorods from substrate surface which led to the formation of films with small-sized and rod-shaped nanostructure is observed by field scanning electron microscopy. Optical transmittance in the visible range increases to reach a maximum value of about 80% for a substrate temperature of 350°C. PL spectra reveal one main broad peak centered around 540 nm with high intensity.

LETTER TO THE EDITOR: Green emission and bandgap narrowing due to two-photon excitation in thin film CdS formed by spray pyrolysis

NASA Astrophysics Data System (ADS)

Ullrich, B.; Schroeder, R.

2001-08-01

Thin (10 µm) film CdS on Pyrex® formed by spray pyrolysis is excited below the gap at 804 nm with 200 fs laser pulses at room temperature. Excitation intensities up to 250 GW cm-2 evoke green bandgap emission due to two-photon transitions. This two-photon photoluminescence does not show a red emission contribution in contrast to the single-photon excited emission, which is dominated by broad emission in the red spectral range. It is demonstrated that two-photon excitation causes photo-induced bandgap narrowing due to Debye screening. At 250 GW cm-2 bandgap narrowing of 47 meV is observed, which corresponds to an excited electron density of 1.6×1018 cm-3.

Growth of pure ZnO thin films prepared by chemical spray pyrolysis on silicon

NASA Astrophysics Data System (ADS)

Ayouchi, R.; Martin, F.; Leinen, D.; Ramos-Barrado, J. R.

2003-01-01

Structural, morphological, optical and electrical properties of ZnO thin films prepared by chemical spray pyrolysis from zinc acetate (Zn(CH 3COO) 2 2H 2O) aqueous solutions, on polished Si(1 0 0), and fused silica substrates for optical characterization, have been studied in terms of deposition time and substrate temperature. The growth of the films present three regimes depending on the substrate temperature, with increasing, constant and decreasing growth rates at lower, middle, and higher-temperature ranges, respectively. Growth rate higher than 15 nm min -1 can be achieved at Ts=543 K. ZnO film morphological and electrical properties have been related to these growth regimes. The films have been characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy.

Vertically aligned carbon nanotubes from natural precursors by spray pyrolysis method and their field electron emission properties

NASA Astrophysics Data System (ADS)

Ghosh, Pradip; Soga, T.; Tanemura, M.; Zamri, M.; Jimbo, T.; Katoh, R.; Sumiyama, K.

2009-01-01

Vertically aligned carbon nanotubes have been synthesized from botanical hydrocarbons: Turpentine oil and Eucalyptus oil on Si(100) substrate using Fe catalyst by simple spray pyrolysis method at 700°C and at atmospheric pressure. The as-grown carbon nanotubes were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), thermogravimetric analysis (TGA), differential thermal analysis (DTA), and Raman spectroscopy. It was observed that nanotubes grown from turpentine oil have better degree of graphitization and field emission performance than eucalyptus oil grown carbon nanotubes. The turpentine oil and eucalyptus oil grown carbon nanotubes indicated that the turn-on field of about 1.7 and 1.93 V/μm, respectively, at 10 μA/cm2. The threshold field was observed to be about 2.13 and 2.9 V/μm at 1 mA/cm2 of nanotubes grown from turpentine oil and eucalyptus oil respectively. Moreover, turpentine oil grown carbon nanotubes show higher current density in relative to eucalyptus oil grown carbon nanotubes. The maximum current density of 15.3 mA/cm2 was obtained for ˜3 V/μm corresponding to the nanotubes grown from turpentine oil. The improved field emission performance was attributed to the enhanced crystallinity, fewer defects, and greater length of turpentine oil grown carbon nanotubes.

The route of liquid precursor to ZnO nanoparticles in premixed combustion spray pyrolysis

NASA Astrophysics Data System (ADS)

Widiyastuti, W.; Machmudah, Siti; Nurtono, Tantular; Winardi, Sugeng

2018-04-01

Zinc oxide nanoparticles had been successfully synthesized by premixed combustion spray pyrolysis. Zinc acetate was dissolved in distilled water was selected as a liquid precursor. Zinc nitrate was also used for comparison the effect of precursor type on the generated particles morphology and the crystallinity. The premixed combustion reaction used liquefied petroleum gas (LPG) mainly consisting of butane and propane as a fuel and compressed air used as an oxidizer. The liquid precursor was atomized using a custom two fluid nozzle to generate droplets. Then, the droplets were sprayed by the flow of air as a carrier gas into the premixed combustion reactor. The zinc precursor was decomposed to zinc oxide due to the high temperature as a result of combustion reaction inside the reactor resulting in nanoparticles formation. The particle size decreased with the increase of the fuel flow rate. In addition, it can be found that at the same flow rate of fuel, the particle size of zinc oxide synthesized using zinc nitrate is larger than that of the use of zinc acetate as a precursor.

Cd-doped ZnO nano crystalline thin films prepared at 723K by spray pyrolysis

NASA Astrophysics Data System (ADS)

Joishy, Sumanth; Rajendra B., V.

2018-04-01

Ternary Zn1-xCdxO(x=0.10, 0.40, 0.70 at.%) thin films of 0.025M precursor concentration have been successfully deposited on preheated (723K) glass substrates using spray pyrolysis route. The structure, morphology and optical properties of deposited films have been characterized by X-ray diffraction, Scanning Electron Microscopy (SEM) and UV-Visible spectrophotometry. X-ray diffraction study shows that the prepared films are polycrystalline in nature. 10% Cd doped ZnO film belongs to the hexagonal wurtzite system and 70% Cd doped ZnO film belongs to the cubic system, although mixed phases were formed for 40% Cd doped ZnO film. The optical transmittance spectra has shown red shift with increasing cadmium content. Optical energy band gap has been reduced with cadmium dopant.

Ethylene glycol assisted spray pyrolysis for the synthesis of hollow BaFe12O19 spheres

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, X; Park, J; Hong, YK

2015-04-01

Hollow spherical BaFe12O19 particles were synthesized by spray pyrolysis from a solution containing ethylene glycol (EG) and precursors at 1000 degrees C. The effects of EG concentration on particle morphology, crystallinity and magnetic properties were investigated. The hollow spherical particles were found to consist of primary particles, and higher EG concentration led to a bigger primary particle size. EG concentration did not show much effect on the hollow particle size. Better crystallinity and higher magnetic coercivity were obtained with higher EG concentration, which is attributed to further crystallization with the heat produced from EG combustion. Saturation magnetization (emu/g) decreased withmore » increasing EG concentration due to residual carbon from EG incomplete combustion, contributing as a non-magnetic phase to the particles. Published by Elsevier B.V.« less

SnS2 Thin Film Deposition by Spray Pyrolysis

NASA Astrophysics Data System (ADS)

Jaber, Abdallah Yahia; Alamri, Saleh Noaiman; Aida, Mohammed Salah

2012-06-01

Tin disulfide (SnS2) thin films have been synthesized using a simplified spray pyrolysis technique using a perfume atomizer. The films were deposited using two different solutions prepared by the dilution of SnCl2 and thiourea in distilled water and in methanol. The obtained films have a microcrystalline structure. The film deposited using methanol as the solvent is nearly stochiometric SnS2 with a spinel phase having a (001) preferential orientation. The film prepared with an aqueous solution is Sn-rich. Scanning electronic microscopy (SEM) images reveal that the film deposited with the aqueous solution is rough and is formed with large wires. However, the film deposited with methanol is dense and smooth. Conductivity measurements indicate that the aqueous solution leads to an n-type semiconductor, while methanol leads to a p-type semiconductor.

Electrical transport properties of spray deposited transparent conducting ortho-Zn2SnO4 thin films

NASA Astrophysics Data System (ADS)

Ramarajan, R.; Thangaraju, K.; Babu, R. Ramesh; Joseph, D. Paul

2018-04-01

Ortho Zinc Stannate (Zn2SnO4) exhibits excellent electrical and optical properties to serve as alternate transparent electrode in optoelectronic devices. Here we have optimized ortho-Zn2SnO4 thin film by spray pyrolysis method. Deposition was done onto a pre-heated glass substrate at a temperature of 400 °C. The XRD pattern indicated films to be polycrystalline with cubic structure. The surface of films had globular and twisted metal sheet like morphologies. Films were transparent in the visible region with band gap around 3.6 eV. Transport properties were studied by Hall measurements at 300 K. Activation energies were calculated from Arrhenius's plot from temperature dependent electrical measurements and the conduction mechanism is discussed.

Zirconium doped TiO2 thin films deposited by chemical spray pyrolysis

NASA Astrophysics Data System (ADS)

Juma, A.; Oja Acik, I.; Oluwabi, A. T.; Mere, A.; Mikli, V.; Danilson, M.; Krunks, M.

2016-11-01

Chemical spray pyrolysis (CSP) is a flexible deposition technique that allows for mixing of the precursor solutions in different proportions suitable for doping thin films. The CSP method was used to dope TiO2 thin films with Zr by adding zirconium(IV) acetylacetonate into a solution of titanium(IV) isopropoxide in ethanol stabilized by acetylacetone at [Zr]/[Ti] of 0, 5, 10 and 20 at%. The Zr-doped TiO2 thin films were uniform and homogeneous showing much smaller grains than the undoped TiO2 films. Zr stabilized the anatase phase to temperatures above 800 °C depending on Zr concentration in the spray solution. The concentration of Zr determined by XPS was 6.4 at% for the thin film deposited from the 20 at% solution. According to AFM studies, Zr doping decreased the root mean square roughness of TiO2 film from 5.9 to 1.1 nm. An XRD study of samples with the highest Zr amount showed the ZrTiO4 phase started forming after annealing at 800 °C. The optical band gap for TiO2 decreased from 3.3 eV to 3.0 eV after annealing at 800 °C but for the TiO2:Zr(20) film it remained at 3.4 eV. The dielectric constant increased by more than four times with Zr-doping and this was associated with the change in the bond formations caused by substitution of Ti by Zr in the lattice.

The synthesis of multifunctional porous honey comb-like La2O3 thin film for supercapacitor and gas sensor applications.

PubMed

Yadav, A A; Lokhande, A C; Pujari, R B; Kim, J H; Lokhande, C D

2016-12-15

The porous honey comb-like La 2 O 3 thin films have been synthesized using one step spray pyrolysis method. The influence of sprayed solution quantity on properties of La 2 O 3 thin films is studied using X-ray diffraction, Fourier transform spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, optical absorption and Brunauer-Emmett-Teller techniques. Morphology of La 2 O 3 electrode is controlled with sprayed solution quantity. The supercapacitive properties of La 2 O 3 thin film electrode are investigated using cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance techniques. The La 2 O 3 film electrode exhibited the specific capacitance of the 166Fg -1 with 85% stability for the 3000 cycles. The La 2 O 3 film electrode exhibited sensitivity of 68 at 523K for 500ppm CO 2 gas concentration. The possible CO 2 sensing mechanism is discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

Immobilized TiO2 nanoparticles produced by flame spray for photocatalytic water remediation

NASA Astrophysics Data System (ADS)

Bettini, Luca Giacomo; Diamanti, Maria Vittoria; Sansotera, Maurizio; Pedeferri, Maria Pia; Navarrini, Walter; Milani, Paolo

2016-08-01

Anatase/rutile mixed-phase titanium dioxide (TiO2) photocatalysts in the form of nanostructured powders with different primary particle size, specific surface area, and rutile content were produced from the gas-phase by flame spray pyrolysis (FSP) starting from an organic solution containing titanium (IV) isopropoxide as Ti precursor. Flame spray-produced TiO2 powders were characterized by means of X-ray diffraction, Raman spectroscopy, and BET measurements. As-prepared powders were mainly composed of anatase crystallites with size ranging from 7 to 15 nm according to the synthesis conditions. TiO2 powders were embedded in a multilayered fluoropolymeric matrix to immobilize the nanoparticles into freestanding photocatalytic membranes. The photocatalytic activity of the TiO2-embedded membranes toward the abatement of hydrosoluble organic pollutants was evaluated employing the photodegradation of rhodamine B in aqueous solution as test reaction. The photoabatement rate of best performing membranes significantly overcomes that of membranes produced by the same method and incorporating commercial P25-TiO2.

Characterization of bidisperse magnetorheological fluids utilizing maghemite (γ-Fe2O3) nanoparticles synthetized by flame spray pyrolysis

NASA Astrophysics Data System (ADS)

Jönkkäri, I.; Sorvali, M.; Huhtinen, H.; Sarlin, E.; Salminen, T.; Haapanen, J.; Mäkelä, J. M.; Vuorinen, J.

2017-09-01

In this study we have used liquid flame spray (LFS) process to synthetize γ-Fe2O3 nanoparticles of two different average sizes. Different sized nanoparticles were generated with two different liquid precursor feed rates in the spray process, higher feed rate resulting in larger nanoparticles with higher saturation magnetization. The nanoparticles were used in bidisperse magnetorheological fluids to substitute 5% of the micron sized carbonyl iron particles. To our knowledge this is the first time particles synthetized by the LFS method have been used in magnetorheological fluids. The bidisperse fluids showed significantly improved sedimentation stability compared to a monodisperse suspension with the same solid concentration. The tradeoff was an increased viscosity without magnetic field. The effect of the nanoparticles on the rheological properties under external magnetic field was modest. Finally, the dynamic oscillatory testing was used to evaluate the structural changes in the fluids under magnetic field. The addition of nanoparticles decreased the elastic portion of the deformation and increased the viscous portion.

Investigations on structural, vibrational, morphological and optical properties of CdS and CdS/Co films by ultrasonic spray pyrolysis

NASA Astrophysics Data System (ADS)

Aksay, S.; Polat, M.; Özer, T.; Köse, S.; Gürbüz, G.

2011-09-01

CdS and CdS/Co films have been deposited on glass substrates by an ultrasonic spray pyrolysis method. The effects of Co incorporation on the structural, optical, morphological, elemental and vibrational properties of these films were investigated. XRD analysis confirmed the hexagonal wurtzite structure of all films and had no impurity phase. While CdS film has (0 0 2) as the preferred orientation, CdS/Co films have (1 1 0) as the preferred orientation. The direct optical band gap was found to decrease from 2.42 to 2.39 eV by Co incorporation. The decrease of the direct energy gaps by increasing Co contents is mainly due to the sp-d exchange interaction between the localized d-electrons of Co2+ ions and band electrons of CdS. After the optical investigations, it was seen that the transmittance of CdS films decreased by Co content. The Raman measurements revealed two peaks corresponding to the 1LO and 2LO modes of hexagonal CdS. The vibrational modes of Cd-S were obtained in the wavenumber range (590-715 cm-1) using Fourier transform infrared spectroscopy (FTIR). The elemental analysis of the film was done by energy dispersive X-ray spectrometry.

Ultrasonic Spray Pyrolysis Deposited Copper Sulphide Thin Films for Solar Cell Applications

PubMed Central

Firat, Y. E.; Yildirim, H.; Erturk, K.

2017-01-01

Polycrystalline copper sulphide (CuxS) thin films were grown by ultrasonic spray pyrolysis method using aqueous solutions of copper chloride and thiourea without any complexing agent at various substrate temperatures of 240, 280, and 320°C. The films were characterized for their structural, optical, and electrical properties by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive analysis of X-rays (EDAX), atomic force microscopy (AFM), contact angle (CA), optical absorption, and current-voltage (I-V) measurements. The XRD analysis showed that the films had single or mixed phase polycrystalline nature with a hexagonal covellite and cubic digenite structure. The crystalline phase of the films changed depending on the substrate temperature. The optical band gaps (Eg) of thin films were 2.07 eV (CuS), 2.50 eV (Cu1.765S), and 2.28 eV (Cu1.765S–Cu2S). AFM results indicated that the films had spherical nanosized particles well adhered to the substrate. Contact angle measurements showed that the thin films had hydrophobic nature. Hall effect measurements of all the deposited CuxS thin films demonstrated them to be of p-type conductivity, and the current-voltage (I-V) dark curves exhibited linear variation. PMID:29109807

Properties of SnO2 thin films deposited by chemical spray pyrolysis using different precursor solutions

NASA Astrophysics Data System (ADS)

Abdul-Hamead, Alaa A.

2018-05-01

In this article single and double nozzle (SN, DN) chemical spray pyrolysis techniques(CSP) proved that tin dioxide SnO2 thin film can be fabricated with different structures. SnO2 prepared from three different salts of tin with a concentration of 0.05 M, with thicknesses were about 0.2 ±0.02 µm. Microstructures inspections were achieved on films, beside optical transparency addition to the contact angle CA. The results show that films have tetragonal crystalline with different micro-structures, from sheet to rod and flower-like aggregates, by the variation of the used salts by DN more than SN, also the value of the CA of the prepared films varies with different structures, reaching its highest value for flower-like aggregates of about 130°. Finally, the optical transparency was different corresponding to the disparity in surfaces roughness and topography.

Structural and magnetic properties of nanocrystalline NiFe2O4 thin film prepared by spray pyrolysis technique

NASA Astrophysics Data System (ADS)

Chavan, Apparao R.; Chilwar, R. R.; Shisode, M. V.; Hivrekar, Mahesh M.; Mande, V. K.; Jadhav, K. M.

2018-05-01

The nanocrystalline NiFe2O4 thin film has been prepared using a spray pyrolysis technique on glass substrate. The prepared thin film was characterized by using X-ray diffraction (XRD), Fourier transform Infrared spectroscopy (FTIR), and Field Emission-Scanning Electron Microscopy (FE-SEM) characterization techniques for the structural and microstructural analysis. The magnetic property was measured using vibrating sample magnetometer (VSM) at room temperature. X-ray diffraction studies show the formation of single phase spinel structure of the thin film. The octahedral and tetrahedral vibration in the sample was studied by Fourier transform infrared (FT-IR) spectra. Magnetic hysteresis loop was recorded for thin film at room temperature. At 15 kOe, saturation magnetization (Ms) was found to increase while coercivity (Hc) decreases with thickness of the NiFe2O4 thin film.

The Effect of Film Composition on the Texture and Grain Size of CuInS2 Prepared by Spray Pyrolysis

NASA Technical Reports Server (NTRS)

Jin, Michael H.; Banger, Kulinder K.; Harris, Jerry D.; Hepp, Aloysius F.

2003-01-01

Ternary single-source precursors were used to deposit CuInS2 thin films using chemical spray pyrolysis. We investigated the effect of the film composition on texture, secondary phase formation, and grain size. As-grown films were most often In-rich. They became more (204/220)-oriented as indium concentration increased, and always contained a yet unidentified secondary phase. The (112)-prefened orientation became more pronounced as the film composition became more Cu-rich. The secondary phase was determined to be an In-rich compound based on composition analysis and Raman spectroscopy. In addition, as-grown Cu-rich (112)-oriented films did not exhibit the In-rich compound. Depositing a thin Cu layer prior to the growth of CuInS2 increased the maximum grain size from - 0.5 micron to - 1 micron, and prevented the formation of the In-rich secondary phase.

Aerosol processing: a wind of innovation in the field of advanced heterogeneous catalysts.

PubMed

Debecker, Damien P; Le Bras, Solène; Boissière, Cédric; Chaumonnot, Alexandra; Sanchez, Clément

2018-06-05

Aerosol processing is long known and implemented industrially to obtain various types of divided materials and nanomaterials. The atomisation of a liquid solution or suspension produces a mist of aerosol droplets which can then be transformed via a diversity of processes including spray-drying, spray pyrolysis, flame spray pyrolysis, thermal decomposition, micronisation, gas atomisation, etc. The attractive technical features of these aerosol processes make them highly interesting for the continuous, large scale, and tailored production of heterogeneous catalysts. Indeed, during aerosol processing, each liquid droplet undergoes well-controlled physical and chemical transformations, allowing for example to dry and aggregate pre-existing solid particles or to synthesise new micro- or nanoparticles from mixtures of molecular or colloidal precursors. In the last two decades, more advanced reactive aerosol processes have emerged as innovative means to synthesise tailored-made nanomaterials with tunable surface properties, textures, compositions, etc. In particular, the "aerosol-assisted sol-gel" process (AASG) has demonstrated tremendous potential for the preparation of high-performance heterogeneous catalysts. The method is mainly based on the low-cost, scalable, and environmentally benign sol-gel chemistry process, often coupled with the evaporation-induced self-assembly (EISA) concept. It allows producing micronic or submicronic, inorganic or hybrid organic-inorganic particles bearing tuneable and calibrated porous structures at different scales. In addition, pre-formed nanoparticles can be easily incorporated or formed in a "one-pot" bottom-up approach within the porous inorganic or hybrid spheres produced by such spray drying method. Thus, multifunctional catalysts with tailored catalytic activities can be prepared in a relatively simple way. This account is an overview of aerosol processed heterogeneous catalysts which demonstrated interesting performance in various relevant chemical reactions like isomerisation, hydrogenation, olefin metathesis, pollutant total oxidation, selective oxidation, CO2 methanation, etc. A short survey of patents and industrial applications is also presented. Our objective is to demonstrate the tremendous possibilities offered by the coupling between bottom up synthesis routes and these aerosol processing technologies which will most probably represent a major route of innovation in the mushrooming field of catalyst preparation research.

Synthesis of nano-structured tin oxide thin films with faster response to LPG and ammonia by spray pyrolysis

NASA Astrophysics Data System (ADS)

PrasannaKumari, K.; Thomas, Boben

2018-01-01

Nanostructured SnO2 thin film have been efficiently fabricated by spray pyrolysis using atomizers of different types. The structure and morphology of as-prepared samples are investigated by techniques such as x-ray diffraction, and field-emission scanning electron microscopy. Significant morphological changes are observed in films by modifying the precursor atomization as a result of change of spray device. The optical characterization indicates that change in atomization, affects the absorbance and the band gap, following the varied crystallite size. Gas sensing investigations on ultrasonically prepared tin oxide films show NH3 response at operating temperatures lower down to 50 °C. For 1000 ppm of LPG the response at 350 °C for air blast atomizer film is about 99%, with short response and recovery times. The photoluminescence emmision spectra reveal the correlation between atomization process and the quantity of oxygen vacancies present in the samples. The favorable size reduction in microstructure with good crystallinity with slight change in lattice properties suggest their scope in gas sensing applications. On the basis of these characterizations, the mechanism of LPG and NH3 gas sensing of nanostructured SnO2 thin films has been proposed.

Spray deposited gallium doped tin oxide thinfilm for acetone sensor application

NASA Astrophysics Data System (ADS)

Preethi, M. S.; Bharath, S. P.; Bangera, Kasturi V.

2018-04-01

Undoped and gallium doped (1 at.%, 2 at.% and 3 at.%) tin oxide thin films were prepared using spray pyrolysis technique by optimising the deposition conditions such as precursor concentration, substrate temperature and spraying rate. X-ray diffraction analysis revealed formation of tetragonally structured polycrystalline films. The SEM micrographs of Ga doped films showed microstructures. The electrical resistivity of the doped films was found to be more than that of the undoped films. The Ga-doped tin oxide thin films were characterised for gas sensors. 1 at.% Ga doped thin films were found to be better acetone gas sensor, showed 68% sensitivity at 350°C temperature.

Chemical spray pyrolyzed kesterite Cu2ZnSnS4 (CZTS) thin films

NASA Astrophysics Data System (ADS)

Khalate, S. A.; Kate, R. S.; Deokate, R. J.

2018-04-01

Pure kesterite phase thin films of Cu2ZnSnS4 (CZTS) were synthesized at different substrate temperatures using sulphate precursors by spray pyrolysis method. The significance of synthesis temperature on the structural, morphological and optical properties has been studied. The X-ray analysis assured that synthesized CZTS thin films showing pure kesterite phase. The value of crystallite size was found maximum at the substrate temperature 400 °C. At the same temperature, microstructural properties such as dislocation density, micro-strain and stacking fault probability were found minimum. The morphological examination designates the development of porous and uniform CZTS thin films. The synthesized CZTS thin films illustrate excellent optical absorption (105 cm-1) in the visible band and the optical band gap varies in the range of 1.489 eV to 1.499 eV.

Semi-automatic spray pyrolysis deposition of thin, transparent, titania films as blocking layers for dye-sensitized and perovskite solar cells.

PubMed

Krýsová, Hana; Krýsa, Josef; Kavan, Ladislav

2018-01-01

For proper function of the negative electrode of dye-sensitized and perovskite solar cells, the deposition of a nonporous blocking film is required on the surface of F-doped SnO 2 (FTO) glass substrates. Such a blocking film can minimise undesirable parasitic processes, for example, the back reaction of photoinjected electrons with the oxidized form of the redox mediator or with the hole-transporting medium can be avoided. In the present work, thin, transparent, blocking TiO 2 films are prepared by semi-automatic spray pyrolysis of precursors consisting of titanium diisopropoxide bis(acetylacetonate) as the main component. The variation in the layer thickness of the sprayed films is achieved by varying the number of spray cycles. The parameters investigated in this work were deposition temperature (150, 300 and 450 °C), number of spray cycles (20-200), precursor composition (with/without deliberately added acetylacetone), concentration (0.05 and 0.2 M) and subsequent post-calcination at 500 °C. The photo-electrochemical properties were evaluated in aqueous electrolyte solution under UV irradiation. The blocking properties were tested by cyclic voltammetry with a model redox probe with a simple one-electron-transfer reaction. Semi-automatic spraying resulted in the formation of transparent, homogeneous, TiO 2 films, and the technique allows for easy upscaling to large electrode areas. The deposition temperature of 450 °C was necessary for the fabrication of highly photoactive TiO 2 films. The blocking properties of the as-deposited TiO 2 films (at 450 °C) were impaired by post-calcination at 500 °C, but this problem could be addressed by increasing the number of spray cycles. The modification of the precursor by adding acetylacetone resulted in the fabrication of TiO 2 films exhibiting perfect blocking properties that were not influenced by post-calcination. These results will surely find use in the fabrication of large-scale dye-sensitized and perovskite solar cells.

Method for making MgO buffer layers on rolled nickel or copper as superconductor substrates

DOEpatents

Paranthaman, Mariappan; Goyal, Amit; Kroeger, Donald M.; List, III, Frederic A.

2002-01-01

Buffer layer architectures are epitaxially deposited on biaxially-textured rolled-Ni and/or Cu substrates for high current conductors, and more particularly buffer layer architectures such as MgO/Ag/Pt/Ni, MgO/Ag/Pd/Ni, MgO/Ag/Ni, MgO/Ag/Pd/Cu, MgO/Ag/Pt/Cu, and MgO/Ag/Cu. Techniques used to deposit these buffer layers include electron beam evaporation, thermal evaporation, rf magnetron sputtering, pulsed laser deposition, metal-organic chemical vapor deposition (MOCVD), combustion CVD, and spray pyrolysis.

Effect of pH of spray solution on the electrical properties of cadmium oxide thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hodlur, R. M.; Gunnagol, Raghu M.; Rabinal, M. K., E-mail: mkrabinal@yahoo.com

2015-06-24

Highly conducting transparent cadmium oxide thin films were prepared by conventional spray pyrolysis technique on glass at 375 °C substrate temperature. The pH of the spray solution was varied by adding ammonia/hydrochloric acid in the spray solution. The XRD pattern showed cubic phase. A lowest resistivity of 9.9 × 10{sup −4} Ω cm (with carrier concentration (n) = 5.1 × 10{sup 20} cm{sup −3}, mobility (µ)=12.4 cm{sup 2}/Vs) is observed for pH ∼12. The resistivity is tuned almost by three orders of magnitude by controlling the bath pH with optical transmittance more than 70 %. Thus, without any doping, the electricalmore » conductivity of CdO films could be easily tuned by simply varying the pH of spray solution without compromising the transparency and keeping the other deposition parameters fixed.« less

Structural and Solar Cell Properties of a Ag-Containing Cu2ZnSnS4 Thin Film Derived from Spray Pyrolysis.

PubMed

Nguyen, Thi Hiep; Kawaguchi, Takato; Chantana, Jakapan; Minemoto, Takashi; Harada, Takashi; Nakanishi, Shuji; Ikeda, Shigeru

2018-02-14

A silver (Ag)-incorporated kesterite Cu 2 ZnSnS 4 (CZTS) thin film was fabricated by a facile spray pyrolysis method. Crystallographic analyses indicated successful incorporation of various amounts of Ag up to a Ag/(Ag + Cu) ratio of ca. 0.1 into the crystal lattice of CZTS in a homogeneous manner without formation of other impurity compounds. From the results of morphological investigations, Ag-incorporated films had larger crystal grains than the CZTS film. The sample with a relatively low Ag content (Ag/(Ag + Cu) of ca. 0.02) had a compact morphology without appreciable voids and pinholes. However, an increase in the Ag content in the CZTS film (Ag/(Ag + Cu) ca. 0.10) induced the formation of a large number of pinholes. As can be expected from these morphological properties, the best sunlight conversion efficiency was obtained by the solar cell based on the film with Ag/(Ag + Cu) of ca. 0.02. Electrostructural analyses of the devices suggested that the Ag-incorporated film in the device achieved reduction in the amounts of unfavorable copper on zinc antisite defects compared to the bare CZTS film. Moreover, the use of a Ag-incorporated film improved band alignment at the CdS(buffer)-CZTS interface. These alterations should also contribute to enhancement of device properties.

Properties of CuInS₂ Nano-Particles on TiO₂ by Spray Pyrolysis for CuInS₂/TiO₂ Composite Solar Cell.

PubMed

Park, Gye-Choon; Li, Zhen-Yu; Yang, O-Bong

2017-04-01

In this letter, for the absorption layer of a CuInS₂/TiO₂ composite solar cell, I–III–VI2 chalcopyrite semiconductor CuInS₂ nano-particles were deposited by using spray pyrolysis method on TiO2 porous film. Their material characteristics including structural and optical properties of CuInS₂ nano-particles on TiO₂ nanorods were analyzed as a function of its composition ratios of Cu:In:S. Crystalline structure, surface morphology and crystalline size were also investigated by X-ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), and High-Resolution TEM (HRTEM), respectively. On the other hand, optical property was characterized by an UV-Visible Spectrophotometer. As a result, it was found that the size of CuInS₂ nano-particles, which was formed at 300±5 °C, was smaller than 16 nm from HRTEM analyses, and it was identified that the CuInS₂ particle size was increased as increasing the heat-treatment temperature and time. However, as the size of CuInS₂ nano-particle becomes smaller, optical absorption edge of ternary compound film tends to move to the blue wavelength band. It turns out that the optical energy-band gap of the compound films was ranging from 1.48 eV to 1.53 eV.

Screen-printed (La,Sr)CrO3 coatings on ferritic stainless steel interconnects for solid oxide fuel cells using nanopowders prepared by means of ultrasonic spray pyrolysis

NASA Astrophysics Data System (ADS)

Brylewski, Tomasz; Dabek, Jaroslaw; Przybylski, Kazimierz; Morgiel, Jerzy; Rekas, Mieczyslaw

2012-06-01

In order to protect the cathode from chromium poisoning and improve electrical resistance, a perovskite (La,Sr)CrO3 coating was deposited on the surface of a DIN 50049 ferritic stainless steel by means of the screen-printing method, using a paste composed of an ultra-fine powder prepared via ultrasonic spray pyrolysis. Investigations of the oxidation process of the coated steel in air and the Ar-H2-H2O gas mixture at 1073 K for times up to 820 h showed high compactness of the protective film, good adhesion to the metal substrate, as well as area specific resistance (ASR) at a level acceptable for metallic SOFC interconnect materials. The microstructure, nanostructure, phase composition of the thick film, and in particular the film/substrate interface, were examined via chemical analyses by means of SEM-EDS and TEM-SAD. It was shown that the (La,Sr)CrO3 coating interacts with the steel during long-term thermal oxidation in the afore-mentioned conditions and intermediate, chromia-rich and/or spinel multilayer interfacial zones are formed. Cr-vaporization tests showed that the (La,Sr)CrO3 coating may play the role of barriers that decrease the volatilization rate of chromia species.

Spray deposition of highly transparent fluorine doped cadmium oxide thin films

NASA Astrophysics Data System (ADS)

Deokate, R. J.; Pawar, S. M.; Moholkar, A. V.; Sawant, V. S.; Pawar, C. A.; Bhosale, C. H.; Rajpure, K. Y.

2008-01-01

The cadmium oxide (CdO) and F:CdO films have been deposited by spray pyrolysis method using cadmium acetate and ammonium fluoride as precursors for Cd and F ions, respectively. The effect of temperature and F doping on the structural, morphological, optical and Hall effect properties of sprayed CdO thin films was investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), optical absorption and electrical measurement techniques. TGA and DTA studies, indicates the formation of CdO by decomposition of cadmium acetate after 250 °C. XRD patterns reveal that samples are polycrystalline with cubic structure and exhibits (2 0 0) preferential orientation. Considerable broading of (2 0 0) peak, simultaneous shifting of corresponding Bragg's angle have been observed with respect to F doping level. SEM and AFM show the heterogeneous distribution of cubical grains all over the substrate, which are randomly distributed. F doping shifts the optical gap along with the increase in the transparency of CdO films. The Hall effect measurement indicates that the resistivity and mobility decrease up to 4% F doping.

Inherent health and environmental risk assessment of nanostructured metal oxide production processes.

PubMed

Torabifard, Mina; Arjmandi, Reza; Rashidi, Alimorad; Nouri, Jafar; Mohammadfam, Iraj

2018-01-10

The health and environmental effects of chemical processes can be assessed during the initial stage of their production. In this paper, the Chemical Screening Tool for Exposure and Environmental Release (ChemSTEER) software was used to compare the health and environmental risks of spray pyrolysis and wet chemical techniques for the fabrication of nanostructured metal oxide on a semi-industrial scale with a capacity of 300 kg/day in Iran. The pollution sources identified in each production process were pairwise compared in Expert Choice software using indicators including respiratory damage, skin damage, and environmental damages including air, water, and soil pollution. The synthesis of nanostructured zinc oxide using the wet chemical technique (with 0.523 wt%) leads to lower health and environmental risks compared to when spray pyrolysis is used (with 0.477 wt%). The health and environmental risk assessment of nanomaterial production processes can help select safer processes, modify the operation conditions, and select or modify raw materials that can help eliminate the risks.

Post-deposition thermal treatment of sprayed ZnO:Al thin films for enhancing the conductivity

NASA Astrophysics Data System (ADS)

Devasia, Sebin; Athma, P. V.; Shaji, Manu; Kumar, M. C. Santhosh; Anila, E. I.

2018-03-01

Here, we report the enhanced conductivity of Aluminium doped (2at.%) zinc oxide thin films prepared by simple spray pyrolysis technique. The structural, optical, electrical, morphological and compositional investigations confirm the better quality of films that can be a potential candidate for application in transparent electronics. Most importantly, the film demonstrates an average transmittance of 90 percent with a low resistivity value which was dropped from 1.39 × 10-2 to 5.10 × 10-3 Ω .cm, after annealing, and a very high carrier concentration in the order of 10 × 20cm-3. Further, we have used the Swanepoel envelop method to calculate thickness, refractive index and extinction coefficient from the interference patterns observed in the transmission spectra. The calculated figure of merit of the as-deposited sample was 1.4 × 10-3Ω-1 which was improved to 2.5 × 10-3Ω-1 after annealing.

Aerosol processing of materials: Aerosol dynamics and microstructure evolution

NASA Astrophysics Data System (ADS)

Gurav, Abhijit Shankar

Spray pyrolysis is an aerosol process commonly used to synthesize a wide variety of materials in powder or film forms including metals, metal oxides and non-oxide ceramics. It is capable of producing high purity, unagglomerated, and micrometer to submicron-size powders, and scale-up has been demonstrated. This dissertation deals with the study of aerosol dynamics during spray pyrolysis of multicomponent systems involving volatile phases/components, and aspects involved with using fuel additives during spray processes to break apart droplets and particles in order to produce powders with smaller sizes. The gas-phase aerosol dynamics and composition size distributions were measured during spray pyrolysis of (Bi, Pb)-Sr-Ca-Cu-O, and Sr-Ru-O and Bi-Ru-O at different temperatures. A differential mobility analyzer (DMA) was used in conjunction with a condensation particle counter (CPC) to monitor the gas-phase particle size distributions, and a Berner-type low-pressure impactor was used to obtain mass size distributions and size-classified samples for chemical analysis. (Bi, Pb)-Sr-Ca-Cu-O powders made at temperatures up to 700sp°C maintained their initial stoichiometry over the whole range of particle sizes monitored, however, those made at 800sp°C and above were heavily depleted in lead in the size range 0.5-5.0 mum. When the reactor temperature was raised from 700 and 800sp°C to 900sp°C, a large number ({˜}10sp7\\ #/cmsp3) of new ultrafine particles were formed from PbO vapor released from the particles and the reactor walls at the beginning of high temperature runs (at 900sp°C). The metal ruthenate systems showed generation of ultrafine particles (<40-50 nm) at the beginning of runs at 800-900sp°C and also as a steady state process at a reactor temperature of 1000sp°C. The methods of aerosol dynamics measurements were also used to monitor the gas-phase particle size distributions during the generation of fullerene (Csb{60}) nano-particles (30 to 50 nm size) via vapor condensation at 400-650sp°C using Nsb2 carrier gas. In general, during laboratory-scale aerosol processing of materials containing a volatile component, significant evaporative losses and formation of new ultrafine particles were observed at synthesis temperatures at which the saturation vapor pressure of the volatile species exceeded about 0.1-0.5 mTorr. Spray calcination synthesis of pigment-size titania from titanium hydrolysate (TiOsb{x}(SOsb4)sb{y}(OH)sb{z}) using fuel additives such as ethyl alcohol, sugar and urea was also investigated. When pure water was used as a medium of suspension, agglomerates of 0.5 to 1.5 mum were produced by spray calcination. Use of pure ethanol as a solvent as well as small amounts (5-10 wt.%) urea additions to the suspension of Ti-hydrolysate in water were successful in producing predominantly unagglomerated, single crystalline titania particles of 0.1 to 0.3 mum size. Such additions of fuels such as alcohols, sugar and urea to suspensions and solutions used in spray processes are promising for making powders having smaller sizes and unagglomerated, denser morphologies.

Generation of functional structures by laser pyrolysis of polysilazane

NASA Astrophysics Data System (ADS)

Krauss, Hans-Joachim; Otto, Andreas

2002-06-01

The pyrolysis of polysilazanes by laser power represents an innovative technique for the generation of ceramic-like coatings and structures. The dissolved polysilazanes can be easily applied by painting techniques such as dipping or spraying. In the following pyrolysis the polysilazane layer transforms into an amorphous ceramic-like coating. The laser power is absorbed in the precursor layer, which leads to the latter's ceramization without damaging the substrate by thermal load. While plane laser pyrolysis creates a protective coating, selective pyrolysis creates a raised and adherent ceramic-like structure that remains after the unexposed polymer layer has been removed. The flexibility of a writing laser system in conjunction with a suitable handling system makes it possible to inscribe any kind of 2D structure on nearly any complexly shaped part. Some of the chemical, magnetic, and electrical structure properties can be adjusted by the pyrolysis parameters and special types of filler particles. Especially the possibility to control electric conductivity should make it possible to create structure dielectric films or planar resistors, inductors or capacitors, which are basically written on the surface of the part. Because of their ceramic nature of the structures are resistant against high temperatures and corrosive media. Thus, this new additive structuring technique could finally strike a new path in creating corrosion resistant high- temperature sensors and control systems.

Computational Analysis of the Optical and Charge Transport Properties of Ultrasonic Spray Pyrolysis-Grown Zinc Oxide/Graphene Hybrid Structures.

PubMed

Ali, Amgad Ahmed; Hashim, Abdul Manaf

2016-12-01

We demonstrate a systematic computational analysis of the measured optical and charge transport properties of the spray pyrolysis-grown ZnO nanostructures, i.e. nanosphere clusters (NSCs), nanorods (NRs) and nanowires (NWs) for the first time. The calculated absorbance spectra based on the time-dependent density functional theory (TD-DFT) shows very close similarity with the measured behaviours under UV light. The atomic models and energy level diagrams for the grown nanostructures were developed and discussed to explain the structural defects and band gap. The induced stresses in the lattices of ZnO NSCs that formed during the pyrolysis process seem to cause the narrowing of the gap between the energy levels. ZnO NWs and NRs show homogeneous distribution of the LUMO and HOMO orbitals all over the entire heterostructure. Such distribution contributes to the reduction of the band gap down to 2.8 eV, which has been confirmed to be in a good agreement with the experimental results. ZnO NWs and NRs exhibited better emission behaviours under the UV excitation as compared to ZnO NSCs and thin film as their visible range emissions are strongly quenched. Based on the electrochemical impedance measurement, the electrical models and electrostatic potential maps were developed to calculate the electron lifetime and to explain the mobility or diffusion behaviours in the grown nanostructure, respectively.

Computational Analysis of the Optical and Charge Transport Properties of Ultrasonic Spray Pyrolysis-Grown Zinc Oxide/Graphene Hybrid Structures

NASA Astrophysics Data System (ADS)

Ali, Amgad Ahmed; Hashim, Abdul Manaf

2016-05-01

We demonstrate a systematic computational analysis of the measured optical and charge transport properties of the spray pyrolysis-grown ZnO nanostructures, i.e. nanosphere clusters (NSCs), nanorods (NRs) and nanowires (NWs) for the first time. The calculated absorbance spectra based on the time-dependent density functional theory (TD-DFT) shows very close similarity with the measured behaviours under UV light. The atomic models and energy level diagrams for the grown nanostructures were developed and discussed to explain the structural defects and band gap. The induced stresses in the lattices of ZnO NSCs that formed during the pyrolysis process seem to cause the narrowing of the gap between the energy levels. ZnO NWs and NRs show homogeneous distribution of the LUMO and HOMO orbitals all over the entire heterostructure. Such distribution contributes to the reduction of the band gap down to 2.8 eV, which has been confirmed to be in a good agreement with the experimental results. ZnO NWs and NRs exhibited better emission behaviours under the UV excitation as compared to ZnO NSCs and thin film as their visible range emissions are strongly quenched. Based on the electrochemical impedance measurement, the electrical models and electrostatic potential maps were developed to calculate the electron lifetime and to explain the mobility or diffusion behaviours in the grown nanostructure, respectively.

Semi-automatic spray pyrolysis deposition of thin, transparent, titania films as blocking layers for dye-sensitized and perovskite solar cells

PubMed Central

Krýsová, Hana; Kavan, Ladislav

2018-01-01

For proper function of the negative electrode of dye-sensitized and perovskite solar cells, the deposition of a nonporous blocking film is required on the surface of F-doped SnO2 (FTO) glass substrates. Such a blocking film can minimise undesirable parasitic processes, for example, the back reaction of photoinjected electrons with the oxidized form of the redox mediator or with the hole-transporting medium can be avoided. In the present work, thin, transparent, blocking TiO2 films are prepared by semi-automatic spray pyrolysis of precursors consisting of titanium diisopropoxide bis(acetylacetonate) as the main component. The variation in the layer thickness of the sprayed films is achieved by varying the number of spray cycles. The parameters investigated in this work were deposition temperature (150, 300 and 450 °C), number of spray cycles (20–200), precursor composition (with/without deliberately added acetylacetone), concentration (0.05 and 0.2 M) and subsequent post-calcination at 500 °C. The photo-electrochemical properties were evaluated in aqueous electrolyte solution under UV irradiation. The blocking properties were tested by cyclic voltammetry with a model redox probe with a simple one-electron-transfer reaction. Semi-automatic spraying resulted in the formation of transparent, homogeneous, TiO2 films, and the technique allows for easy upscaling to large electrode areas. The deposition temperature of 450 °C was necessary for the fabrication of highly photoactive TiO2 films. The blocking properties of the as-deposited TiO2 films (at 450 °C) were impaired by post-calcination at 500 °C, but this problem could be addressed by increasing the number of spray cycles. The modification of the precursor by adding acetylacetone resulted in the fabrication of TiO2 films exhibiting perfect blocking properties that were not influenced by post-calcination. These results will surely find use in the fabrication of large-scale dye-sensitized and perovskite solar cells. PMID:29719764

High-throughput screening of nanoparticle catalysts made by flame spray pyrolysis as hydrocarbon/NO oxidation catalysts.

PubMed

Weidenhof, B; Reiser, M; Stöwe, K; Maier, W F; Kim, M; Azurdia, J; Gulari, E; Seker, E; Barks, A; Laine, R M

2009-07-08

We describe here the use of liquid-feed flame spray pyrolysis (LF-FSP) to produce high surface area, nonporous, mixed-metal oxide nanopowders that were subsequently subjected to high-throughput screening to assess a set of materials for deNO(x) catalysis and hydrocarbon combustion. We were able to easily screen some 40 LF-FSP produced materials. LF-FSP produces nanopowders that very often consist of kinetic rather than thermodynamic phases. Such materials are difficult to access or are completely inaccessible via traditional catalyst preparation methods. Indeed, our studies identified a set of Ce(1-x)Zr(x)O(2) and Al(2)O(3)-Ce(1-x)Zr(x)O(2) nanopowders that offer surprisingly good activities for both NO(x) reduction and propane/propene oxidation both in high-throughput screening and in continuous flow catalytic studies. All of these catalysts offer activities comparable to traditional Pt/Al(2)O(3) catalysts but without Pt. Thus, although Pt-free, they are quite active for several extremely important emission control reactions, especially considering that these are only first generation materials. Indeed, efforts to dope the active catalysts with Pt actually led to lower catalytic activities. Thus the potential exists to completely change the materials used in emission control devices, especially for high-temperature reactions as these materials have already been exposed to 1500 degrees C; however, much research must be done before this potential is verified.

Comparative study on structural and optical properties of CdS films fabricated by three different low-cost techniques

NASA Astrophysics Data System (ADS)

Ravichandran, K.; Philominathan, P.

2009-03-01

Highly crystalline and transparent cadmium sulphide films were fabricated at relatively low temperature by employing an inexpensive, simplified spray technique using perfume atomizer (generally used for cosmetics). The structural, surface morphological and optical properties of the films were studied and compared with that prepared by conventional spray pyrolysis using air as carrier gas and chemical bath deposition. The films deposited by the simplified spray have preferred orientation along (1 0 1) plane. The lattice parameters were calculated as a = 4.138 Å and c = 6.718 Å which are well agreed with that obtained from the other two techniques and also with the standard data. The optical transmittance in the visible range and the optical band gap were found as 85% and 2.43 eV, respectively. The structural and optical properties of the films fabricated by the simplified spray are found to be desirable for opto-electronic applications.

Synthesis of Zn1- x Co x Al2O4 Spinel Nanoparticles by Liquid-Feed Flame Spray Pyrolysis: Ceramic Pigments Application

NASA Astrophysics Data System (ADS)

Betancur Granados, Natalia; Yi, Eongyu; Laine, Richard M.; Restrepo Baena, Oscar Jaime

2016-01-01

Zn1- x Co x Al2O4 ( x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) spinel nanoparticles were synthesized by a liquid-feed flame spray pyrolysis (LF-FSP) method by combusting metallorganic precursor solutions to produce nanopowders with precise composition control. The precursor solutions were aerosolized into a methane/oxygen flame where it was combusted in an oxygen-rich environment to result in nanopowders at a single step. The nanopowders were analyzed by x-ray diffraction, Fourier transform infrared spectroscopy, colorimetry, field emission scanning electron microscopy, transmission electron microscopy, and BET (Brunauer-Emmett-Teller) N2 adsorption. Results show formation of spherical nanopowders with specific surface areas of 42 m2/g to 50 m2/g, which correspond to average particle sizes of 26 nm to 31 nm. Single-phase materials were obtained with a high control of composition, which indicates that LF-FSP is an excellent method to produce mixed-metal oxides for applications in which powder homogeneity is crucial. The products were evaluated for ceramic pigment application, where the ratio of Zn to Co was gradually changed to observe the color change in the structure with the increase of cobalt concentration. The resulting pigments were calcined at 1200°C, which aimed to identify the color stability after a high-temperature process, whereby the colors were measured using the color space CIE L*a*b* under standardized light, D65. Finally, the powders were tested for ceramic decoration using transparent glazes and ceramic bodies. The application was carried out at 1250°C to evaluate the color performance after a decoration process.

Perovskite Quantum Dots with Near Unity Solution and Neat-Film Photoluminescent Quantum Yield by Novel Spray Synthesis.

PubMed

Dai, Shu-Wen; Hsu, Bo-Wei; Chen, Chien-Yu; Lee, Chia-An; Liu, Hsiao-Yun; Wang, Hsiao-Fang; Huang, Yu-Ching; Wu, Tien-Lin; Manikandan, Arumugam; Ho, Rong-Ming; Tsao, Cheng-Si; Cheng, Chien-Hong; Chueh, Yu-Lun; Lin, Hao-Wu

2018-02-01

In this study, a novel perovskite quantum dot (QD) spray-synthesis method is developed by combining traditional perovskite QD synthesis with the technique of spray pyrolysis. By utilizing this new technique, the synthesis of cubic-shaped perovskite QDs with a homogeneous size of 14 nm is demonstrated, which shows an unprecedented stable absolute photoluminescence quantum yield ≈100% in the solution and even in the solid-state neat film. The highly emissive thin films are integrated with light emission devices (LEDs) and organic light emission displays (OLEDs). The color conversion type QD-LED (ccQD-LED) hybrid devices exhibit an extremely saturated green emission, excellent external quantum efficiency of 28.1%, power efficiency of 121 lm W -1 , and extraordinary forward-direction luminescence of 8 500 000 cd m -2 . The conceptual ccQD-OLED hybrid display also successfully demonstrates high-definition still images and moving pictures with a 119% National Television System Committee 1931 color gamut and 123% Digital Cinema Initiatives-P3 color gamut. These very-stable, ultra-bright perovskite QDs have the properties necessary for a variety of useful applications in optoelectronics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

THE PRODUCTION OF THIN METAL OXIDE FILMS BY SPRAY PYROLYSIS USING SUPERCRITICAL CO2-ASSISTED AEROSOLIZATION OF AQUEOUS SOLUTIONS. (R824728)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Condensation of acetol and acetic acid vapor with sprayed liquid

USDA-ARS?s Scientific Manuscript database

A cellulose-derived fraction of biomass pyrolysis vapor was simulated by evaporating acetol and acetic acid (AA) from flasks on a hot plate. The liquid in the flasks was infused with heated nitrogen. The vapor/nitrogen stream was superheated in a tube oven and condensed by contact with a cloud of ...

Effects of the precursor concentration and different annealing ambients on the structural, optical, and electrical properties of nanostructured V2O5 thin films deposited by spray pyrolysis technique

NASA Astrophysics Data System (ADS)

Irani, Rowshanak; Rozati, Seyed Mohammad; Beke, Szabolcs

2018-04-01

V2O5 thin films were deposited with different precursor concentrations of 0.01, 0.05, and 0.1 M on glass substrates by spray pyrolysis technique, then the optimized films were annealed in different ambients (air, oxygen, and vacuum). The results showed that by increasing the concentration, the films grew along the (001) direction with an orthorhombic structure. Field emission scanning electron microscopy showed that nanorods were formed when depositing 0.05 molar of VCl3. We conclude that with the precursor concentration, the surface nanostructure can be well-controlled. Annealing improved the crystallinity under all ambients, but the best crystallinity was achieved in vacuum. It was revealed that the as-deposited films had the highest transmission, whereas the films annealed in air had the lowest. When annealed in air, the optical band gap decreased from 2.45 to 2.32 eV. The sheet resistance, resistivity, mobility, conductivity, and carrier concentration were measured for all the prepared V2O5 films.

Scalable synthesis of aligned carbon nanotubes bundles using green natural precursor: neem oil

NASA Astrophysics Data System (ADS)

Kumar, Rajesh; Tiwari, Radhey Shyam; Srivastava, Onkar Nath

2011-12-01

Practical application of aligned carbon nanotubes (ACNTs) would have to be determined by a matter of its economical and large-scale preparation. In this study, neem oil (also named Margoaa oil, extracted from the seeds of the neem-- Azadirachta indica) was used as carbon source to fabricate the bundles of ACNTs. ACNTs have been synthesized by spray pyrolysis of neem oil and ferrocene mixture at 825°C. The major components of neem oil are hydrocarbon with less amount of oxygen, which provided the precursor species in spray pyrolysis growth of CNTs. The bundles of ACNTs have been grown directly inside the quartz tube. The as-grown ACNTs have been characterized through Raman spectroscopy, scanning and transmission electron microscopic (SEM/TEM) techniques. SEM images reveal that the bundles of ACNTs are densely packed and are of several microns in length. High-resolution TEM analysis reveals these nanotubes to be multi-walled CNTs. These multi-walled CNTs were found to have inner diameter between 15 and 30 nm. It was found that present technique gives high yield with high density of bundles of ACNTs.

Scalable synthesis of aligned carbon nanotubes bundles using green natural precursor: neem oil.

PubMed

Kumar, Rajesh; Tiwari, Radhey Shyam; Srivastava, Onkar Nath

2011-01-18

Practical application of aligned carbon nanotubes (ACNTs) would have to be determined by a matter of its economical and large-scale preparation. In this study, neem oil (also named Margoaa oil, extracted from the seeds of the neem--Azadirachta indica) was used as carbon source to fabricate the bundles of ACNTs. ACNTs have been synthesized by spray pyrolysis of neem oil and ferrocene mixture at 825°C. The major components of neem oil are hydrocarbon with less amount of oxygen, which provided the precursor species in spray pyrolysis growth of CNTs. The bundles of ACNTs have been grown directly inside the quartz tube. The as-grown ACNTs have been characterized through Raman spectroscopy, scanning and transmission electron microscopic (SEM/TEM) techniques. SEM images reveal that the bundles of ACNTs are densely packed and are of several microns in length. High-resolution TEM analysis reveals these nanotubes to be multi-walled CNTs. These multi-walled CNTs were found to have inner diameter between 15 and 30 nm. It was found that present technique gives high yield with high density of bundles of ACNTs.

Synthesis of Li2Ti3O7 Anode Materials by Ultrasonic Spray Pyrolysis and Their Electrochemical Properties

PubMed Central

Ogihara, Takashi; Kodera, Takayuki

2013-01-01

Ramsdellite-type lithium titanate (Li2Ti3O7) powders were synthesized by performing ultrasonic spray pyrolysis, and their chemical and physical properties were characterized by performing Scanning Electron Microscope (SEM), powder X-ray Diffraction (XRD), and Inductively Coupled Plasma (ICP) analyses. The as-prepared Li2Ti3O7 precursor powders had spherical morphologies with hollow microstructures, but an irregularly shaped morphology was obtained after calcination above 900 °C. The ramsdellite Li2Ti3O7 crystal phase was obtained after the calcination at 1100 °C under an argon/hydrogen atmosphere. The first rechargeable capacity of the Li2Ti3O7 anode material was 168 mAh/g at 0.1 C and 82 mAh/g at 20 C, and the discharge capacity retention ratio was 99% at 1 C after the 500th cycle. The cycle performance of the Li2Ti3O7 anode was also highly stable at 50 °C, demonstrating the superiority of Li2Ti3O7 anode materials reported previously. PMID:28809274

Growth of nanocrystalline Cu2ZnSnS4 thin films using the spray pyrolysis technique and their characterization

NASA Astrophysics Data System (ADS)

Chandel, Tarun; Halaszova, Sona; Prochazka, Michal; Hasko, Daniel; Velic, Dusan; Thakur, Vikas; Dwivedi, Shailendra Kumar; Zaman, M. Buhanuz; Rajaram, Poolla

2018-05-01

Nanocrystalline thin films of Cu2ZnSnS4 (CZTS) were grown on the glass substrates using the spray pyrolysis technique. The films were grown at a substrate temperature of 300 °C after which they were annealed at 350 °C in vacuum. X-ray diffraction (XRD) studies showed that the films crystallized in the kesterite structure. Energy dispersive analysis of X-rays (EDAX) studies showed that the films possess the desired stoichiometry i.e. the proportion of Cu:Zn:Sn:S in the CZTS solid solution is close to 2:1:1:4. Secondary Ions Mass Spectroscopy (SIMS) depth profiling confirmed the uniformity in elemental composition along the depth of the films. SEM studies showed that the films are covered with CZTS particles forming sheet like structures. AFM studies show that the size of the particles on the surface of the films is around 10-15 nm. UV-VIS-NIR transmission spectra were used to determine the optical band gap of the CZTS films which was found to be around 1.55eV.

Efficient acetone sensor based on Ni-doped ZnO nanostructures prepared by spray pyrolysis technique

NASA Astrophysics Data System (ADS)

Darunkar, Swapnil S.; Acharya, Smita A.

2018-05-01

Ni-doped ZnO thin film was prepared by home-built spray pyrolysis unit for the detection of acetone at 300°C. Scanning electron microscopic (SEM) images of as-developed thin film of undoped ZnO exhibits large quantity of spherical, non-agglomerated particles with uniform size while in Ni-doped ZnO, particles are quite non-uniform in nature. The particle size estimated by using image J are obtained to be around 20-200 nm. Ni-doping effect on band gaps are determined by UV-vis optical spectroscopy and band gap of Ni-doped ZnO is found to be 3.046 eV. Nickel doping exceptionally enhances the sensing response of ZnO as compared to undoped ZnO system. The major role of the Ni-doping is to create more active sites for chemisorbed oxygen on the surface of sensor and correspondingly, to improve the sensing response. The 6 at.% of Ni-doped ZnO exhibits the highest response (92%) for 100 ppm acetone at 300 °C.

Transparent nanostructured Fe-doped TiO2 thin films prepared by ultrasonic assisted spray pyrolysis technique

NASA Astrophysics Data System (ADS)

Rasoulnezhad, Hossein; Hosseinzadeh, Ghader; Ghasemian, Naser; Hosseinzadeh, Reza; Homayoun Keihan, Amir

2018-05-01

Nanostructured TiO2 and Fe-doped TiO2 thin films with high transparency were deposited on glass substrate through ultrasonic-assisted spray pyrolysis technique and were used in the visible light photocatalytic degradation of MB dye. The resulting thin films were characterized by scanning electron microscopy (SEM), Raman spectroscopy, photoluminescence spectroscopy, x-ray diffraction (XRD), and UV-visible absorption spectroscopy techniques. Based on Raman spectroscopy results, both of the TiO2 and Fe-doped TiO2 films have anatase crystal structure, however, because of the insertion of Fe in the structure of TiO2 some point defects and oxygen vacancies are formed in the Fe-doped TiO2 thin film. Presence of Fe in the structure of TiO2 decreases the band gap energy of TiO2 and also reduces the electron–hole recombination rate. Decreasing of the electron–hole recombination rate and band gap energy result in the enhancement of the visible light photocatalytic activity of the Fe-doped TiO2 thin film.

Synthesis of Carbon Nano Materials Originated from Waste Cooking Oil Using a Nebulized Spray Pyrolysis

NASA Astrophysics Data System (ADS)

Arie, A. A.; Hadisaputra, L.; Susanti, R. F.; Devianto, H.; Halim, M.; Enggar, R.; Lee, J. K.

2017-07-01

Synthesis of nanocarbon on snake fruit-peel’s activated carbon from waste cooking oil palm was conducted by a nebulized spray pyrolysis process (NSP) by varying the processing temperature from 650 to 750 °C. Ferrocene was used as a catalyst with constant concentration of 0.015 g/ml of carbon source. The structure of nanocarbon was studied by using scanning electron microscope (SEM),x-ray diffraction (XRD), surface area analyzer and Raman spectroscopy. SEM results showed that the structures of carbon products was in the the form of carbon nanopsheres (CNS). XRD and Raman analysis confirmed the CNS structure. The carbon producs were then tested as electrode’s materials for lithium ion capacitors (LIC) by cyclic voltammetry (CV) instruments. From the CV results the specific capacitance was estimated as 79.57 F / g at a scan rate of 0.1 mV / s and voltage range from 2.5 - 4 V. This study shows that the nano carbons synthesized from the waste cooking oil can be used as prospective electrode materials for LIC.

Ultrasonic spray pyrolysis synthesis of reduced graphene oxide/anatase TiO2 composite and its application in the photocatalytic degradation of methylene blue in water.

PubMed

Park, Jeong-Ann; Yang, Boram; Lee, Joongki; Kim, In Gyeom; Kim, Jae-Hyun; Choi, Jae-Woo; Park, Hee-Deung; Nah, In Wook; Lee, Sang-Hyup

2018-01-01

Reduced graphene oxide (RGO)/anatase TiO 2 composite was prepared using a simple one-step technique-ultrasonic spray pyrolysis-in order to inhibit the aggregation of TiO 2 nanoparticles and to improve the photocatalytic performance for degradation of methylene blue (MB). Different proportions (0-5 wt%) of RGO/TiO 2 composites were characterized by scanning electronic microscopy (SEM), dispersive X-ray spectrometry (EDS), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) surface area, X-ray photoelectron spectroscopy (XPS), X-ray diffractometry (XRD), Raman spectroscopy, UV-vis spectroscopy, and electrochemical impedance spectroscopy (EIS) to verify mechanism. From these analysis, TiO 2 nanoparticles are distributed uniformly on the RGO sheets with crumpled shape during ultrasonic spray pyrolysis and surface area is increasing by increasing portion of RGO. Band gap of RGO 5 /TiO 2 (5 wt% of RGO) composite is 2.72 eV and band gap was reduced by increasing portion of RGO in RGO/TiO 2 composites. The RGO 5 /TiO 2 composite was superior to other lower content of RGO/TiO 2 composites with a rapid transport of charge carriers and an effective charge separation. The highest removal efficiency of MB was obtained at the RGO 5 /TiO 2 composite under UVC irradiation, which coincided with the EIS, and the optimal dose of the composite was determined to be 0.5 g/L. The RGO 5 /TiO 2 composite improve the photocatalytic degradation rate of MB over the TiO 2 due to a retardation of electron-hole recombination. The MB adsorption capacity and photocatalytic degradation efficiency were greatly affected by pH changes and increased with increasing pH due to electrostatic interactions and generation of more hydroxyl radicals. The reusability of RGO 5 /TiO 2 composite was examined during 3 cycles. Copyright © 2017 Elsevier Ltd. All rights reserved.

Visible light-induced water oxidation on mesoscopic alpha-Fe2O3 films made by ultrasonic spray pyrolysis.

PubMed

Duret, Alexis; Grätzel, Michael

2005-09-15

Alpha-Fe(2)O(3) films having a mesoscopic leaflet type structure were produced for the first time by ultrasonic spray pyrolysis (USP) to explore their potential as oxygen-evolving photoanodes. The target of these studies is to use translucent hematite films deposited on conducting fluorine doped tin oxide (FTO) glass as top electrodes in a tandem cell that accomplishes the cleavage of water into hydrogen and oxygen by sunlight. The properties of layers made by USP were compared to those deposited by conventional spray pyrolysis (SP). Although both types of films show similar XRD and UV-visible and Raman spectra, they differ greatly in their morphology. The mesoscopic alpha-Fe(2)O(3) layers produced by USP consist mainly of 100 nm-sized platelets with a thickness of 5-10 nm. These nanosheets are oriented mainly perpendicularly to the FTO support, their flat surface exposing (001) facets. The mesoscopic leaflet structure has the advantage that it allows for efficient harvesting of visible light, while offering at the same time the very short distance required for the photogenerated holes to reach the electrolyte interface before recombining with conduction band electrons. This allows for water oxidation by the valence band holes even though their diffusion length is only a few nanometers. Distances are longer in the particles produced by SP favoring recombination of photoinduced charge carriers. Open-circuit photovoltage measurements indicate a lower surface state density for the nanoplatelets as compared to the round particles. These factors explain the much higher photoactivity of the USP compared to the SP deposited alpha-Fe(2)O(3) layers. Addition of hydrogen peroxide to the alkaline electrolyte further improves the photocurrent-voltage characteristics of films generated by USP indicating the hole transfer from the valence band of the semiconductor oxide to the adsorbed water to be the rate-limiting kinetic step in the oxygen generation reaction.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Widjaja, Ongky, E-mail: wijayaongky@yahoo.co.id; Arie, Arenst Andreas, E-mail: arenst@unpar.ac.id; Halim, Martin

In this work, kerosene oil based nanocarbons were synthesized by a nebulized spray pyrolysis method. This method was conducted at temperature of 700°C under a nitrogen inert atmospheric condition. Activated carbon and ferrocene were used as substrate and catalyst, respectively. Initially, ferrocene was dissolved in the oil with fixed concentration of 0.02 g/ml. The pyrolysis reaction was carried out by varying the operating time of 15, 30 and 45 minutes. The main aim of this work was to investigate the effect of varying the operation time on the morphology and structural characteristics of as-prepared carbon products. The morphology and structural characteristicsmore » of synthesized nanocarbons were examined by Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM), and Raman Spectroscopy, respectively. SEM and TEM observations showed that nano carbons were formed as agglomerated carbon nanospheres (CNSs) and graphene for all variation of operating time. Furthermore, it was observed that the size of agglomerated CNSs was proportional with the operating time from 15 to 45 minutes. Raman analysis showed that the ratio between graphite like and disorder carbon structure (I{sub G}/I{sub D})of carbon samples increased from operating time of 15 to 30 minutes, however the ratio decreased from 30 minutes to 45 minutes.« less

ZnO layers prepared by spray pyrolysis

NASA Astrophysics Data System (ADS)

Messaoudi, C.; Abd-Lefdil, S.; Sayah, D.; Cadene, M.

1998-02-01

Highly transparent undoped and indium doped ZnO thin films have been grown on glass substrates by using the spray pyrolysis process. Conditions of preparation have been optimized to get good quality and reproducible films with required properties. Polycrystalline films with an hexagonal Wurtzite-type structure were easily obtained under the optimum spraying conditions. Both of samples have shown high transmission coefficient in the visible and infrared wavelength range with sharp absorption edge around 380 nm which closely corresponds to the intrinsic band-gap of ZnO (3.2 eV). Orientation and crystallites size were remarkably modified by deposition temperature and indium doping. Des couches minces de ZnO, hautement transparentes, non dopées et dopées à l'indium ont été élaborées sur un substrat en verre par le procédé de pulvérisation chimique réactive spray. Les conditions de préparation ont été optimisées pour l'obtention de couches reproductibles, de bonne qualité et ayant les propriétés requises. Des films polycristallins, présentant une structure hexagonale de type Wurtzite, ont été aisément obtenus dans les conditions optimales de pulvérisation. Tous les échantillons ont présenté un coefficient de transmission élevé dans le domaine du visible et du proche infrarouge, avec une absorption brutale au voisinage de 380 nm, correspondant au gap optique du ZnO (3,2 eV). L'orientation et la taille des cristallites ont été remarquablement modifiées par la température du dépôt et par le dopage à l'indium.

Single-source precursors for ternary chalcopyrite materials, and methods of making and using the same

NASA Technical Reports Server (NTRS)

Banger, Kulbinder K. (Inventor); Hepp, Aloysius F. (Inventor); Harris, Jerry D. (Inventor); Jin, Michael Hyun-Chul (Inventor); Castro, Stephanie L. (Inventor)

2006-01-01

A single source precursor for depositing ternary I-III-VI.sub.2 chalcopyrite materials useful as semiconductors. The single source precursor has the I-III-VI.sub.2 stoichiometry built into a single precursor molecular structure which degrades on heating or pyrolysis to yield the desired I-III-VI.sub.2 ternary chalcopyrite. The single source precursors effectively degrade to yield the ternary chalcopyrite at low temperature, e.g. below 500.degree. C., and are useful to deposit thin film ternary chalcopyrite layers via a spray CVD technique. The ternary single source precursors according to the invention can be used to provide nanocrystallite structures useful as quantum dots. A method of making the ternary single source precursors is also provided.

Influence of substrate temperature on structural, morphological, optical and electrical properties of Bi-doped MnInS4 thin films prepared by nebuliser spray pyrolysis technique

NASA Astrophysics Data System (ADS)

Kennedy, A.; Senthil Kumar, V.; Pradeev Raj, K.

2017-11-01

Bismuth (Bi)-doped manganese indium sulphide (MnInS4) thin films were deposited on heated glass substrates using an aqueous solution of MnCl2, InCl3, (NH2)2CS and BiCl3 by the common nebuliser spray pyrolysis technique. The thin films were grown at various substrate temperatures ranging from 250 to 400 °C with a constant spray time (5 min). The present work aims to study the effect of substrate temperature on the structural, optical, photoluminescence and electrical properties of the grown thin films using various techniques like X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive spectrum (EDS), UV-Vis absorption spectroscopy, photoluminescence spectra (PL) and four probe methods. The XRD pattern reveals that the Bi-doped MnInS4 thin films were polycrystalline in nature with a cubic spinel structure whose particle size varies between 8.2 and 23.5 nm. From the FE-SEM micrographs, due to the change in the substrate temperature, shapes such as spherical, needle-shaped and T-shaped grains were observed throughout the surface of the films. The energy dispersive analysis spectrum (EDS) shows the presence of Mn, In, S and Bi in the film grown at 250 °C. It is interesting to note that the structural homogeneity and crystallinity of the film is improved due to the decrease in the absorption coefficient (α) and extinction coefficient (K) with an increase in substrate temperature. Also, with an increase in the substrate temperature, the calculated band gap energy was found to decrease from 1.87 to 1.59 eV. From the PL spectra, several intense peaks corresponding to blue, green, yellow, orange and red band emissions were observed in the wavelength region of 350-650 nm. Moreover as the intensity of the peak increases with increase in the substrate temperature, the crystallinity of the material of the film greatly improves concomitant with minimum strain and defect states. From the electrical studies, the electrical conductivity increases with increase in substrate temperature and a maximum electrical conductivity of 3.73 × 10-3 Ω-1m-1 were obtained for the film prepared at 400 °C. The thickness of the films was also measured and the values ranged between 743 nm (250 °C) to 629 nm (400 °C). The high absorption coefficient (1.85 × 104 cm-1) and high transmittance of the films make them an efficient window layer for solar cell applications. Incorporation of Bismuth (Bi) into MnInS4 matrix leads to improve the optical transmittance (85%) and electrical conductivity (3.11 × 10-3 Ω-1 m-1) of the film grown at 400 °C. Other important parameters like dislocation density (δ), strain (ε), the number of crystallites per unit area (N) and lattice distortion (LD), which are commonly used to describe the structural analysis were also presented. Bi-doped MnInS4 thin films were grown by a variety of deposition methods. Among them, spray pyrolysis is an eco-friendly method because of its low cost, mass production capacity, large area coatings and minimum wastage of the source materials.

Synthesis and characterization of nanosized calcium phosphates by flame spray pyrolysis, and their effect on osteogenic differentiation of stem cells

NASA Astrophysics Data System (ADS)

Ataol, Sibel; Tezcaner, Ayşen; Duygulu, Ozgur; Keskin, Dilek; Machin, Nesrin E.

2015-02-01

The present study evaluates the synthesis of biocompatible osteoconductive and osteoinductive nano calcium phosphate (CaP) particles by industrially applied, aerosol-derived flame spray pyrolysis method for biomedical field. Calcium phosphate nanoparticles were produced in a range of calcium-to-phosphorus ratio, (1.20-2.19) in order to analyze the morphology and crystallinity changes, and to test the bioactivity of particles. The characterization results confirmed that nanometer-sized, spherical calcium phosphate particles were produced. The average primary particle size was determined as 23 nm by counting more than 500 particles in TEM pictures. XRD patterns, HRTEM, SAED, and SEM analyses revealed the amorphous nature of the as-prepared nano calcium phosphate particles at low Ca/P ratios. Increases in the specific surface area and crystallinity were observed with the increasing Ca/P ratio. TGA-DTA analysis showed that the thermally stable crystal phases formed after 700 °C. Cell culture studies were conducted with urine-derived stem cells that possess the characteristics of mesenchymal stem cells. Synthesized amorphous nanoparticles did not have cytotoxic effect at 5-50 μg/ml concentration range. Cells treated with the as-prepared nanoparticles had higher alkaline phosphatase (ALP) enzyme activity than control cells, indicating osteogenic differentiation of cells. A slight decrease in ALP activity of cells treated with two highest Ca:P ratios at 50 μg/ml concentration was observed at day 7. The findings suggest that calcium phosphate nanoparticles produced in this work have a potential to be used as biomaterials in biomedical applications.

Origins of conductivity improvement in fluoride-enhanced silicon doping of ZnO films.

PubMed

Rashidi, Nazanin; Vai, Alex T; Kuznetsov, Vladimir L; Dilworth, Jonathan R; Edwards, Peter P

2015-06-07

Fluoride in spray pyrolysis precursor solutions for silicon-doped zinc oxide (SiZO) transparent conductor thin films significantly improves their electrical conductivity by enhancing silicon doping efficiency and not, as previously assumed, by fluoride doping. Containing only earth-abundant elements, SiZO thus prepared rivals the best solution-processed indium-doped ZnO in performance.

Influence of Annealing Duration on the Growth of V2O5 Nanorods Synthesized by Spray Pyrolysis Technique

NASA Astrophysics Data System (ADS)

Abd-Alghafour, N. M.; Ahmed, Naser M.; Hassan, Z.; Abubakar, D.; Bououdina, M.

2016-06-01

This paper deals with the investigation of annealing effects on the structural, morphological and optical properties of V2O5 nanorods (NRs) grown on the glass substrates by using chemical spray pyrolysis technique. The as-prepared samples were annealed at 500∘ for 40, 60 and 120 min in a quartz tube furnace. The high resolution X-ray diffraction (XRD) analysis revealed V2O5 NRs with preferred orientation along (001) plane. The crystallite size of the V2O5 NRs was increased by increasing the annealing duration. The morphological observations using field emission scanning electron microscope (FESEM) displayed NRs structures whose diameter and length were found to increase with increase of the annealing duration. The transmission electron microscopy (TEM) analysis confirmed the orthorhombic structures of the NRs. The AFM measurements indicated an increase of the average surface roughness by increasing the annealing time. The Raman spectroscopy revealed V-O-V phonon mode in the NRs annealed for 120 min. The optical bandgap was found in the range 2.6-2.58eV and observed to decrease with various duration annealed.

Effect of S-doping on structural, optical and electrochemical properties of vanadium oxide thin films prepared by spray pyrolysis

NASA Astrophysics Data System (ADS)

Mousavi, M.; Kompany, A.; Shahtahmasebi, N.; Bagheri-Mohagheghi, M.-M.

2013-12-01

In this research, S-doped vanadium oxide thin films, with doping levels from 0 to 40 at.%, are prepared by spray pyrolysis technique on glass substrates. For electrochemical measurements, the films were deposited on florin-tin oxide coated glass substrates. The effect of S-doping on structural, electrical, optical and electrochemical properties of vanadium oxide thin films was studied. The x-ray diffractometer analysis indicated that most of the samples have cubic β-V2O5 phase structure with preferred orientation along [200]. With increase in the doping levels, the structure of the samples tends to be amorphous. The scanning electron microscopy images show that the structure of the samples is nanobelt-shaped and the width of the nanobelts decreases from nearly 100 to 40 nm with increase in the S concentration. With increase in the S-doping level, the sheet resistance and the optical band gap increase from 940 to 4015 kΩ/square and 2.41 to 2.7 eV, respectively. The cyclic voltammogram results obtained for different samples show that the undoped sample is expanded and the sample prepared at 20 at.% S-doping level has sharper anodic and cathodic peaks.

The effect of solution concentration on the physical and electrochemical properties of vanadium oxide films deposited by spray pyrolysis

NASA Astrophysics Data System (ADS)

Mousavi, M.; Kompany, A.; Shahtahmasebi, N.; Bagheri-Mohagheghi, M. M.

2013-10-01

Vanadium oxide thin films were prepared on glass substrates by using the spray pyrolysis technique. The effect of solution concentration (0.1 M, 0.2 M and 0.3 M) on the nanostructural, electrical, optical, and electrochromic properties of deposited films were investigated using X-ray diffraction, scanning electron microscopy, UV—vis spectroscopy, and cyclic volta-metrics. The X-ray diffraction shows that only the sample at 0.1 M has a single β-V2O5 phase and the others have mixed phases of vanadium oxide. The lowest sheet resistance was obtained for the samples prepared at 0.3 M solution. It was also found that the optical transparency of the samples changes from 70% to 35% and the optical band gap of the samples was in the range of 2.20 to 2.41 eV, depending on the morality of solution. The cycle voltammogram shows that the sample prepared at 0.3 M has one-step electerochoromic but the other samples have two-step electerochoromic. The results show a correlation between the cycle voltammogram and the physical properties of the films.

Spray pyrolysis deposition and photoelectrochemical properties of n-type BiOI nanoplatelet thin films.

PubMed

Hahn, Nathan T; Hoang, Son; Self, Jeffrey L; Mullins, C Buddie

2012-09-25

Bismuth oxy-iodide is a potentially interesting visible-light-active photocatalyst; yet there is little research regarding its photoelectrochemical properties. Herein we report the synthesis of BiOI nanoplatelet photoelectrodes by spray pyrolysis on fluorine-doped tin oxide substrates at various temperatures. The films exhibited n-type conductivity, most likely due to the presence of anion vacancies, and optimized films possessed incident photon conversion efficiencies of over 20% in the visible range for the oxidation of I(-) to I(3)(-) at 0.4 V vs Ag/AgCl in acetonitrile. Visible-light photons (λ > 420 nm) contributed approximately 75% of the overall photocurrent under AM1.5G illumination, illustrating their usefulness under solar light illumination. A deposition temperature of 260 °C was found to result in the best performance due to the balance of morphology, crystallinity, impurity levels, and optical absorption, leading to photocurrents of roughly 0.9 mA/cm(2) at 0.4 V vs Ag/AgCl. Although the films performed stably in acetonitrile, their performance decreased significantly upon extended exposure to water, which was apparently caused by a loss of surface iodine and subsequent formation of an insulating bismuth hydroxide layer.

Effect of Pr3+doping on key properties of CdO thin films deposited by spray pyrolysis using perfume atomizer

NASA Astrophysics Data System (ADS)

Ravikumar, M.; Chandramohan, R.; Kumar, K. Deva Arun; Valanarasu, S.; Kathalingam, A.; Ganesh, V.; Shkir, Mohd.; AlFaify, S.; Algarni, H.

2018-07-01

High quality Cadmium oxide thin films doped with Praseodymium (Pr) were prepared using perfume atomizer based spray pyrolysis technique at substrate temperature near 350 °C. Structural analysis of films was examined by XRD and confirmed that the films are cubic in structure. All un-doped and doped films were good crystalline in nature with smooth and flat surface without significant modifications owed to doping. Optical transmittances of doped films was decrease in the visible and IR range with increasing Pr doping concentration. Band gap widened from 2.42 to 2.20 eV when doped with Pr from 0 to 5 at. %. In addition, the photoluminescence property of the films was also observed. Further, the electrical studies were performed on pure and doped samples Viz., the electrical resistivity, carrier concentration (ρ) and Hall mobility (μ). It confirmed that the deposited films has good structural environments in terms of grain size, absolute stress correspond and low resistivity. Current-voltage measurements on the nanostructured Al/Pr-nCdO/p-Si/Al device showed a non-linear electric characteristics indicating diode like behavior.

Selenization of CIS and CIGS layers deposited by chemical spray pyrolysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Babu, B. J.; Egaas, B.; Velumani, S.

Cu(In1-xGax)Se2 (CIGS) thin films with x=0 (CIS) and x=0.3 (CIGS) were prepared on Mo-coated glass substrate by using chemical spray pyrolysis at a substrate temperature of 350 degrees C, followed by selenization treatment at 550 degrees C in selenium environment under N2 gas flow. X-ray diffraction patterns of as-deposited CIGS layers on Mo showed polycrystalline chalcopyrite phase with an intense (112) plane. Splitting of (204)/(220) and (116)/(312) planes for the film with x=0.3 reveals deviation of tetragonal nature. Field emission scanning electron microscopy cross-sectional images of selenized films showed clear re-crystallization of grains. During the selenization process of the CIGSmore » absorber, a thin interface layer of MoSe2 is formed. Line mapping of Mo/CIGS layer showed more gallium segregation at the interface of back contact resulting in band gap grading. Chemical composition and mapping of the as-deposited and selenized samples were determined by energy dispersive analysis of X-rays. This work leads to fabrication of low cost and large scale Mo/CIGS/CdS/ZnO/ZnO:Al device structure.« less

Synthesis of Al2O3 thin films using laser assisted spray pyrolysis (LASP)

NASA Astrophysics Data System (ADS)

Dhonge, Baban P.; Mathews, Tom; Tripura Sundari, S.; Krishnan, R.; Balamurugan, A. K.; Kamruddin, M.; Subbarao, R. V.; Dash, S.; Tyagi, A. K.

2013-01-01

The present study reports the development of a laser assisted ultrasonic spray pyrolysis technique and synthesis of dense optical alumina films using the same. In this technique ultrasonically generated aerosols of aluminum acetylacetonate dissolved in ethanol and a laser beam (Nd:YAG, CW, 1064 nm) were fed coaxially and concurrently through a quartz tube on to a hot substrate mounted on an X-Y raster stage. At the laser focused spot the precursor underwent solvent evaporation and solute sublimation followed by precursor vapor decomposition giving rise to oxide coating, the substrate is rastered to get large surface area coating. The surface morphology revealed coalescence of particles with increase in laser power. The observed particle sizes were 17 nm for films synthesized without laser and 18, 21 and 25 nm for films made with laser at 25, 38 and 50 W, respectively. Refractive index of the films synthesized increased from 1.56 to 1.62 as the laser power increased from 0 to 50 W. The stoichiometry of films was studied using XPS and the increase in interfacial layer thickness with laser power was observed from dynamic SIMS depth profiling and ellipsometry.

57Fe CEMS study on dilute metal ions codoped SnO2 thin films prepared by spray pyrolysis

NASA Astrophysics Data System (ADS)

Nomura, Kiyoshi; Koike, Yuya; Nakanishi, Akio

2017-11-01

Dilute Mn-Fe, Co-Fe and V-Fe codoped tin oxide films prepared by spray pyrolysis were characterized by 57Fe conversion electron Mössbauer spectrometry (CEMS) at room temperature (RT) and at 20 K. Two kinds of paramagnetic Fe3+ species were detected at RT; one doublet 1 (D1) with IS = 0.36-0.37 mm/s, QS = 0.69-0.75 mm/s and LW = 0.32-0.40 mm/s, and another doublet 2 (D2) with IS = 0.31-0.35 mm/s QS = 1.16-1.25 mm/s and LW = 0.46-0.52 mm/s. CEMS at 20 K provided more distinguished doublets than at RT. It is found that especially D2 with relatively small IS and large QS values are influenced by other metal ions codoped in SnO2 matrix, whereas D1 with relatively large IS and small QS has the parameters close to the models of Fe-VO1 and Fe-2VO1-Fe models (Nomura et al. Phys. Rev. B 75, 184411 2007; Mudarra Navarro et al. J. Phys. Chem. C 119, 5596-5603 2015).

High power density cell using nanostructured Sr-doped SmCoO3 and Sm-doped CeO2 composite powder synthesized by spray pyrolysis

NASA Astrophysics Data System (ADS)

Shimada, Hiroyuki; Yamaguchi, Toshiaki; Suzuki, Toshio; Sumi, Hirofumi; Hamamoto, Koichi; Fujishiro, Yoshinobu

2016-01-01

High power density solid oxide electrochemical cells were developed using nanostructure-controlled composite powder consisting of Sr-doped SmCoO3 (SSC) and Sm-doped CeO2 (SDC) for electrode material. The SSC-SDC nano-composite powder, which was synthesized by spray pyrolysis, had a narrow particle size distribution (D10, D50, and D90 of 0.59, 0.71, and 0.94 μm, respectively), and individual particles were spherical, composing of nano-size SSC and SDC fragments (approximately 10-15 nm). The application of the powder to a cathode for an anode-supported solid oxide fuel cell (SOFC) realized extremely fine cathode microstructure and excellent cell performance. The anode-supported SOFC with the SSC-SDC cathode achieved maximum power density of 3.65, 2.44, 1.43, and 0.76 W cm-2 at 800, 750, 700, and 650 °C, respectively, using humidified H2 as fuel and air as oxidant. This result could be explained by the extended electrochemically active region in the cathode induced by controlling the structure of the starting powder at the nano-order level.

Effect of Sn doping on the structural, optical and electrical properties of TiO2 films prepared by spray pyrolysis

NASA Astrophysics Data System (ADS)

Arunachalam, A.; Dhanapandian, S.; Manoharan, C.

2016-02-01

In this work, highly oriented pure and Tin-doped Titanium dioxide (Sn-doped TiO2) with porous nature photoelectrodes were deposited on ITO glass plates using spray pyrolysis technique. The XRD pattern revealed the formation of anatase TiO2 with the maximum intensity of (101) plane while doping 6 at% of Sn. The morphological studies depicted the porous nature with the uniform arrangement of small-sized grains. The presence of tin confirmed with the EDX spectra. The size of particles of 13 nm was observed from High Resolution Transmission Electron Microscopy (HR-TEM) analysis. The average transmittance was about 85% for the doped photoelectrode and was observed for the photoelectrode deposited with 6 at% of tin, with decreased energy band gap. The PL study showed the emission peak at 391 nm. The maximum carrier concentration and Hall mobility was observed for the photoelectrode deposited with 6 at% of tin. With these studies, the DSSCs were prepared separately with the dye extracted from Hibiscus Rosasinesis and Hibiscus Surttasinesis and their efficiency was maximum for the DSSC prepared with 6 at% of tin.

Visualization of the evaporation of a diesel spray using combined Mie and Rayleigh scattering techniques

NASA Astrophysics Data System (ADS)

Adam, Anne; Leick, Philippe; Bittlinger, Gerd; Schulz, Christof

2009-09-01

Evaporating Diesel sprays are studied by laser Rayleigh scattering measurements in an optically accessible high-pressure/high-temperature cell that reproduces the thermodynamic conditions which exist in the combustion chamber of a Diesel engine during injection. n-Decane is injected into the vessel using a state-of-the-art near-production three-hole nozzle. Global images of the distributions of the liquid and vapor phases of the injected fuel are obtained using a combined Schlieren and Mie scattering setup. More details about the evaporation are revealed when the spray is illuminated by a laser light sheet: laser light can be scattered by molecules in the gas phase (Rayleigh scattering) or comparably large fuel droplets (Mie scattering). The former is seen in regions where the fuel has completely evaporated, and the latter is dominant in regions with high droplet concentrations. Studying the polarization of the signal light allows the distinction of three different regions in the spray that are characterized by a moderate, low or negligible concentration of liquid fuel droplets. The characteristics of fuel evaporation are investigated for different observation times after the start of injection, chamber conditions and injection pressures. For the quantification of the fuel concentration measurements based on Rayleigh scattering, a calibration method that uses propane as a reference gas is presented and tested. At high ambient temperatures, the accuracy of the concentration measurements is limited by pyrolysis of the fuel molecules.

Thermographic Phosphors for High Temperature Measurements: Principles, Current State of the Art and Recent Applications

PubMed Central

Khalid, Ashiq Hussain; Kontis, Konstantinos

2008-01-01

This paper reviews the state of phosphor thermometry, focusing on developments in the past 15 years. The fundamental principles and theory are presented, and the various spectral and temporal modes, including the lifetime decay, rise time and intensity ratio, are discussed. The entire phosphor measurement system, including relative advantages to conventional methods, choice of phosphors, bonding techniques, excitation sources and emission detection, is reviewed. Special attention is given to issues that may arise at high temperatures. A number of recent developments and applications are surveyed, with examples including: measurements in engines, hypersonic wind tunnel experiments, pyrolysis studies and droplet/spray/gas temperature determination. They show the technique is flexible and successful in measuring temperatures where conventional methods may prove to be unsuitable. PMID:27873836

Process for thin film deposition of cadmium sulfide

DOEpatents

Muruska, H. Paul; Sansregret, Joseph L.; Young, Archie R.

1982-01-01

The present invention teaches a process for depositing layers of cadmium sulfide. The process includes depositing a layer of cadmium oxide by spray pyrolysis of a cadmium salt in an aqueous or organic solvent. The oxide film is then converted into cadmium sulfide by thermal ion exchange of the O.sup.-2 for S.sup.-2 by annealing the oxide layer in gaseous sulfur at elevated temperatures.

Methods and apparatuses for preparing upgraded pyrolysis oil

DOEpatents

Brandvold, Timothy A; Baird, Lance Awender; Frey, Stanley Joseph

2013-10-01

Methods and apparatuses for preparing upgraded pyrolysis oil are provided herein. In an embodiment, a method of preparing upgraded pyrolysis oil includes providing a biomass-derived pyrolysis oil stream having an original oxygen content. The biomass-derived pyrolysis oil stream is hydrodeoxygenated under catalysis in the presence of hydrogen to form a hydrodeoxygenated pyrolysis oil stream comprising a cyclic paraffin component. At least a portion of the hydrodeoxygenated pyrolysis oil stream is dehydrogenated under catalysis to form the upgraded pyrolysis oil.

Properties of NiO thin films deposited by chemical spray pyrolysis using different precursor solutions

NASA Astrophysics Data System (ADS)

Cattin, L.; Reguig, B. A.; Khelil, A.; Morsli, M.; Benchouk, K.; Bernède, J. C.

2008-07-01

NiO thin films have been deposited by chemical spray pyrolysis using a perfume atomizer to grow the aerosol. The influence of the precursor, nickel chloride hexahydrate (NiCl 2·6H 2O), nickel nitrate hexahydrate (Ni(NO 3) 2·6H 2O), nickel hydroxide hexahydrate (Ni(OH) 2·6H 2O), nickel sulfate tetrahydrate (NiSO 4·4H 2O), on the thin films properties has been studied. In the experimental conditions used (substrate temperature 350 °C, precursor concentration 0.2-0.3 M, etc.), pure NiO thin films crystallized in the cubic phase can be achieved only with NiCl 2 and Ni(NO 3) 2 precursors. These films have been post-annealed at 425 °C for 3 h either in room atmosphere or under vacuum. If all the films are p-type, it is shown that the NiO films conductivity and optical transmittance depend on annealing process. The properties of the NiO thin films annealed under room atmosphere are not significantly modified, which is attributed to the fact that the temperature and the environment of this annealing is not very different from the experimental conditions during spray deposition. The annealing under vacuum is more efficient. This annealing being proceeded in a vacuum no better than 10 -2 Pa, it is supposed that the modifications of the NiO thin film properties, mainly the conductivity and optical transmission, are related to some interaction between residual oxygen and the films.

Effect of solvent composition on oxide morphology during flame spray pyrolysis of metal nitrates.

PubMed

Strobel, Reto; Pratsinis, Sotiris E

2011-05-28

The effect of solvent composition on particle formation during flame spray pyrolysis of inexpensive metal-nitrates has been investigated for alumina, iron oxide, cobalt oxide, zinc oxide and magnesium oxide. The as-prepared materials were characterized by electron microscopy, nitrogen adsorption, X-ray diffraction (XRD) and disc centrifugation (XDC). The influence of solvent parameters such as boiling point, combustion enthalpy and chemical reactivity on formation of either homogeneous nanoparticles by evaporation/nucleation/coagulation (gas-to-particle conversion) or large particles through precipitation and conversion within the sprayed droplets (droplet-to-particle conversion) is discussed. For Al(2)O(3), Fe(2)O(3), Co(3)O(4) and partly also MgO, the presence of a carboxylic acid in the FSP solution resulted in homogeneous nanoparticles. This is attributed to formation of volatile metal carboxylates in solution as evidenced by attenuated total reflectance spectroscopy (ATR). For ZnO and MgO rather homogeneous nanoparticles were formed regardless of solvent composition. For ZnO this is attributed to its relatively low dissociation temperature compared to other oxides. While for MgO this is traced to the high decomposition temperature of Mg(NO(3))(2) together with Mg(OH)(2)↔MgO transformations. Cobalt oxide (Co(3)O(4)) nanoparticles made by FSP were not aggregated but rather loosely agglomerated as determined by the excellent agreement between XRD- and XDC-derived crystallite and particle sizes, respectively, pointing out the potential of FSP to make non-aggregated particles. This journal is © the Owner Societies 2011

A Systems Approach to Bio-Oil Stabilization - Final Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Robert C; Meyer, Terrence; Fox, Rodney

2011-12-23

The objective of this project is to develop practical, cost effective methods for stabilizing biomass-derived fast pyrolysis oil for at least six months of storage under ambient conditions. The U.S. Department of Energy has targeted three strategies for stabilizing bio-oils: (1) reducing the oxygen content of the organic compounds comprising pyrolysis oil; (2) removal of carboxylic acid groups such that the total acid number (TAN) of the pyrolysis oil is dramatically reduced; and (3) reducing the charcoal content, which contains alkali metals known to catalyze reactions that increase the viscosity of bio-oil. Alkali and alkaline earth metals (AAEM), are knownmore » to catalyze decomposition reactions of biomass carbohydrates to produce light oxygenates that destabilize the resulting bio-oil. Methods envisioned to prevent the AAEM from reaction with the biomass carbohydrates include washing the AAEM out of the biomass with water or dilute acid or infusing an acid catalyst to passivate the AAEM. Infusion of acids into the feedstock to convert all of the AAEM to salts which are stable at pyrolysis temperatures proved to be a much more economically feasible process. Our results from pyrolyzing acid infused biomass showed increases in the yield of anhydrosugars by greater than 300% while greatly reducing the yield of light oxygenates that are known to destabilize bio-oil. Particulate matter can interfere with combustion or catalytic processing of either syngas or bio-oil. It also is thought to catalyze the polymerization of bio-oil, which increases the viscosity of bio-oil over time. High temperature bag houses, ceramic candle filters, and moving bed granular filters have been variously suggested for syngas cleaning at elevated temperatures. High temperature filtration of bio-oil vapors has also been suggested by the National Renewable Energy Laboratory although there remain technical challenges to this approach. The fast pyrolysis of biomass yields three main organic products: condensable vapors, non-condensable gases, and liquid aerosols. Traditionally these are recovered by a spray quencher or a conventional shell and tube condenser. The spray quencher or condenser is typically followed by an electrostatic precipitator to yield 1 or 2 distinct fractions of bio-oil. The pyrolyzer system developed at Iowa State University incorporates a proprietary fractionating condenser train. The system collects the bio-oil into five unique fractions. For conditions typical of fluidized bed pyrolyzers, stage fractions have been collected that are carbohydrate-rich (anhydrosugars), lignin-rich, and an aqueous solution of carboxylic acids and aldehydes. One important feature is that most of the water normally found in bio-oil appears in the last stage fraction along with several water-soluble components that are thought to be responsible for bio-oil aging (low molecular weight carboxylic acids and aldehydes). Research work on laser diagnostics for hot-vapor filtration and bio-oil recovery centered on development of analytical techniques for in situ measurements during fast pyrolysis, hot-vapor filtration, and fractionation relative to bio-oil stabilization. The methods developed in this work include laser-induced breakdown spectroscopy (LIBS), laser-induced incandescence (LII), and laser scattering for elemental analysis (N, O, H, C), detection of particulates, and detection of aerosols, respectively. These techniques were utilized in simulated pyrolysis environments and applied to a small-scale pyrolysis unit. Stability of Bio-oils is adversely affected by the presence of particulates that are formed as a consequence of thermal pyrolysis, improving the CFD simulations of moving bed granular filter (MBGF) is useful for improving the design of MBGF for bio-oil production. The current work uses fully resolved direct numerical simulation (where the flow past each granule is accurately represented) to calculate the filter efficiency that is used in the CFD model at all flow speeds. This study shows that fully-resolved direct numerical simulation (DNS) is successful in calculating the filter efficiency at all speeds. Aldehydes and acids are thought to play key roles in the stability of bio-oils, so the catalytic stabilization of bio-oils was focused on whether a reaction approach could be employed that simultaneously addressed these two types of molecules in bio-oil. Our approach to post treatment was simultaneous hydrogenation and esterification using bifunctional metal/acidic heterogeneous catalyst in which reactive aldehydes were reduced to alcohols, creating a high enough alcohol concentration so that the carboxylic acids could be esterified.« less

Solvent-free Hydrodeoxygenation of Bio-oil Model Compounds Cyclopentanone and Acetophenone over Flame-made Bimetallic Pt-Pd/ZrO2 Catalysts

PubMed Central

Jiang, Yijiao; Büchel, Robert; Huang, Jun; Krumeich, Frank; Pratsinis, Sotiris E.; Baiker, Alfons

2013-01-01

Bimetallic Pt-Pd/ZrO2 catalysts with different Pt/Pd atomic ratio and homogeneous dispersion of the metal nanoparticles were prepared in a single step by flame-spray pyrolysis. The catalysts show high activity and tuneable product selectivity for the solvent-free hydrodeoxygenation of the bio-oil model compounds cyclopentanone and acetophenone. PMID:22674738

H2 Production Under Visible Light Irradiation from Aqueous Methanol Solution on CaTiO3:Cu Prepared by Spray Pyrolysis

NASA Astrophysics Data System (ADS)

Lim, Sung Nam; Song, Shin Ae; Jeong, Yong-Cheol; Kang, Hyun Woo; Park, Seung Bin; Kim, Ki Young

2017-10-01

Perovskite-type photocatalysts of CaCu x Ti1- x O3 (0 ≤ x ≤ 0.02) powder were prepared by spray pyrolysis of aqueous solution or aqueous solution with polymeric additive. The effects of the amount of copper ions doped in the photocatalyst and the precursor type on the photocatalytic activity under visible-light irradiation were investigated. The crystal structure, oxidation state, and light adsorption properties of the prepared photocatalysts were analyzed using x-ray diffraction, x-ray photoelectron spectroscopy, and diffuse reflectance spectroscopy, respectively. The doping of copper ions in CaTiO3 allowed visible-light absorption owing to a narrowing of the band gap energy of the host material through the formation of a new donor level for copper ions. Among the doped samples prepared from the aqueous precursor, CaTiO3 doped with 1 mol.% copper ions had the highest hydrogen evolution rate (140.7 μmol g-1 h-1). Notably, the hydrogen evolution rate of the photocatalyst doped with 1 mol.% copper ions prepared from the aqueous precursor with polymeric additive (295.0 μmol g-1 h-1) was two times greater than that prepared from the aqueous precursor, due to the morphology effect.

Luminescence optimization of MBO 3:Eu 3+ (M=Y, Gd, Al) red phosphor by spray pyrolysis using combinatorial chemistry

NASA Astrophysics Data System (ADS)

Youl Jung, Kyeong

2010-08-01

Conventional solution-based combinatorial chemistry was combined with spray pyrolysis and applied to optimize the luminescence properties of (Y x, Gd y, Al z)BO 3:Eu 3+ red phosphor under vacuum ultraviolet (VUV) excitation. For the Y-Gd-Al ternary system, a compositional library was established to seek the optimal composition at which the highest luminescence under VUV (147 nm) excitation could be achieved. The Al content was found to mainly control the relative peak ratio (R/O) of red and orange colors due to the 5D 0→ 7F 2 to 5D 0→ 7F 1 transitions of Eu 3+. The substitution of Gd atoms in the place of Y sites did not contribute to change the R/O ratio, but was helpful to enhance the emission intensity. As a result, the 613 nm emission peak due to the 5D 0→ 7F 2 transitions of Eu 3+ was intensified by increasing the Al/Gd ratio at a fixed Y content, resulting in the improvement of the color coordinate. Finally, the optimized host composition was (Y 0.11, Gd 0.10, Al 0.79)BO 3 in terms of the emission intensity at 613 nm and the color coordinate.

Evaluation of Nd-Loaded SnO2:F Films Coated via Spray Pyrolysis

NASA Astrophysics Data System (ADS)

Turgut, G.

2018-05-01

Thin layers of single (F)- and double (F/Nd)-incorporated tin oxide have been coated on glass substrate via spray pyrolysis. The structural, morphological, electrical, and optical features of F-incorporated samples were evaluated depending on the Nd loading. X-ray diffraction analysis revealed that samples had tetragonal tin oxide structure with (211) and (200) preferential directions. The crystallite size and strain values varied from 37.98 nm and 1.21 × 10-3 to 52.12 nm and 1.88 × 10-3. Scanning electron microscopy analysis showed that the samples consisted of pyramidal, polyhedral, and needle-shaped granules. The lowest sheet resistance value of 1.22 Ω was found for 1.8 at.% Nd + 25 at.% F-coloaded SnO2. However, the widest optical bandgap of 4.01 eV was observed for the single 25 at.% F-loaded sample. The Urbach tail and figure of merit also changed in the ranges of 664 meV to 1296 meV and 6.4 × 10-2 Ω-1 to 2.3 × 10-3 Ω-1, respectively. The results presented herein indicate that the character of F-doped tin oxide films can be controlled by Nd loading and that these films could be useful for technological applications.

Thickness dependent optical properties of PEMA and (PEMA){sub 0.85}/(ZnO){sub 0.15} nanocomposite films deposited by spray pyrolysis technique on ITO substrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thakur, Anjna, E-mail: anjna56@gmail.com; Thakur, Priya; Yadav, Kamlesh, E-mail: kamlesh.yadav001@gmail.com

2016-05-06

In this paper, poly (ethyl methacrylate) (PEMA) and (PEMA){sub 0.85}/(ZnO){sub 0.15} nanocomposite films for 2, 3, 4 and 5 minutes have been deposited by spray pyrolysis technique on indium tin oxide (ITO) coated substrate. The effect of thickness of the film on the morphological and optical properties of PEMA and (PEMA){sub 0.85}/(ZnO){sub 0.15} nanocomposite films are studied. The morphological and optical properties of pure PEMA and (PEMA){sub 0.85}/(ZnO){sub 0.15} nanocomposite films are compared. The field emission scanning electron microscopy (FESEM) shows that as the thickness of film increases, uniformity of films increases. It is found from UV-Visible spectra that themore » energy band gap decreases with increasing the deposition time and refractive index increases with increasing the thickness of the film. The band gap of the nanocomposites is found less than the pure polymer film and opposite trend is observed for refractive index. The optical absorption of PEMA/ZnO nanocomposite films is higher than pure PEMA film. The thickness of the nanocomposite film plays a significant role in the tunability of the optical properties.« less

Plasmonic metamaterial-based chemical converted graphene/TiO2/Ag thin films by a simple spray pyrolysis technique

NASA Astrophysics Data System (ADS)

Kumar, Promod; Swart, H. C.

2018-04-01

Graphene based hybrid nanostructures have received special attention in both the scientific and technological development due to their unique physicochemical behavior, which make them attractive in various applications such as, batteries, supercapacitors, fuel cells, solar cells, photovoltaic devices and bio-sensors. In the present study, the role of plasmonic metamaterials in light trapping photovoltaics for inorganic semiconducting materials by a simple and low cost spray pyrolysis technique has been studied. The plasmonic metamaterials thin film has been fabricated by depositing chemically converted graphene (CCG) onto TiO2-Ag nanoparticles which has a low resistivity and a low electron-hole recombination probability. The localized surface plasmon resonance at the metal-dielectric interface for the Ag nanoparticles has been observed at 403 nm after depositing chemical converted graphene (CCG) on the TiO2-Ag thin film. The results suggest that the stacking order of the CCG/TiO2/Ag plasmonic metamaterials samples did not change the band gap of TiO2 while it changed the conductivity of the film. Thus the diffusion of the noble metals in the glass and TiO2 matrices based thin films can trap the light of a particular wavelength by mean of plasmonic resonance and may be useful for superior photovoltaic and optoelectronic applications.

Evaluation of Nd-Loaded SnO2:F Films Coated via Spray Pyrolysis

NASA Astrophysics Data System (ADS)

Turgut, G.

2018-07-01

Thin layers of single (F)- and double (F/Nd)-incorporated tin oxide have been coated on glass substrate via spray pyrolysis. The structural, morphological, electrical, and optical features of F-incorporated samples were evaluated depending on the Nd loading. X-ray diffraction analysis revealed that samples had tetragonal tin oxide structure with (211) and (200) preferential directions. The crystallite size and strain values varied from 37.98 nm and 1.21 × 10-3 to 52.12 nm and 1.88 × 10-3. Scanning electron microscopy analysis showed that the samples consisted of pyramidal, polyhedral, and needle-shaped granules. The lowest sheet resistance value of 1.22 Ω was found for 1.8 at.% Nd + 25 at.% F-coloaded SnO2. However, the widest optical bandgap of 4.01 eV was observed for the single 25 at.% F-loaded sample. The Urbach tail and figure of merit also changed in the ranges of 664 meV to 1296 meV and 6.4 × 10-2 Ω-1 to 2.3 × 10-3 Ω-1, respectively. The results presented herein indicate that the character of F-doped tin oxide films can be controlled by Nd loading and that these films could be useful for technological applications.

In2O3-based multicomponent metal oxide films and their prospects for thermoelectric applications

NASA Astrophysics Data System (ADS)

Korotcenkov, G.; Brinzari, V.; Cho, B. K.

2016-02-01

Thermoelectric properties of In2O3-SnO2-based multi-component metal oxide films formed by spray pyrolysis method are studied. It is shown that the introduction of additional components such as gallium and zinc can control the parameters of the deposited layers. At that, the doping with gallium is more effective for optimization of the efficiency of the thermoelectric conversion. The explanation of the observed changes in the electro-physical and thermoelectric properties of the films at the composition change is given. It is found that the main changes in the properties of multicomponent metal oxide films take place at concentrations of dopants which correspond to their limit solubility in the dominant oxide.

Preparation, characterization and gas sensing performance of BaTiO3 nanostructured thin films

NASA Astrophysics Data System (ADS)

Suryawanshi, Dinesh N.; Pathan, Idris G.; Bari, Anil. R.; Patil, Lalchand A.

2018-05-01

Spray pyrolysis techniques was employed to prepare BaTiO3 thin films. AR grade solutions of Barium chloride (0.05 M) and Titanium chloride (0.05 M) were mixed in the proportion of 30:70, 50:50 and 70:30. The solutions were sprayed on quartz substrate heated at 350°C temperature to obtain the films. These thin films were annealed for a two hours at 600°C in air medium respectively. The prepared thin films were characterized using XRD, FESEM, EDAX, TEM. The electrical and gas sensing properties of these films were investigated. 50:50 film showed better response to Liquid Petroleum Gas (LPG) as compare 30:70 and 70:30 films.

Preparation and characterization of sprayed FTO thin films

NASA Astrophysics Data System (ADS)

Abd-Lefdil, M.; Diaz, R.; Bihri, H.; Aouaj, M. Ait; Rueda, F.

2007-06-01

Fluorine doped tin oxide (FTO) thin films have been prepared by spray pyrolysis technique with no further annealing. Films with 2.5% of fluorine grown at 400 °C present a single phase and exhibit a tetragonal structure with lattice parameters a = 4.687 Å and c = 3.160 Å. Scanning electron micrographs showed homogeneous surfaces with average grain size around 190 nm. The films are transparent in the visible zone and exhibit a high reflectance in the near infrared region. The best electrical resistivity was 6.3 × 10-4 Ω cm for FTO with 2.5% of fluorine. The ratio of transmittance in the visible to the sheet resistance are in the 0.57 × 10-2 1.96 × 10-2 {Ω }-1 range.

Influence of spray time on the optical and electrical properties of CoNi2S4 thin films

NASA Astrophysics Data System (ADS)

El Radaf, I. M.; Fouad, S. S.; Ismail, A. M.; Sakr, G. B.

2018-04-01

In this paper, a facile spray pyrolysis technique was utilized to synthesize CoNi2S4 thin films. The influence of spray time on the structural, optical and electrical properties of the CoNi2S4 thin films was studied. The x-ray diffraction studies of the CoNi2S4 thin films illustrate that the films exhibit a polycrystalline nature with cubic structure. The values of the lattice strain ε, and the dislocation density δ, were decreased as the spray time increase while the grain size has reverse manner to lattice strain ε, and the dislocation density δ. The transmittance and reflectance spectra of the CoNi2S4 thin films were recorded in the wavelength range of (400–2500) nm to evaluate the optical parameters of the CoNi2S4 thin films. Optical absorption coefficient of CoNi2S4 thin films revealed a presence of a direct energy gap and the values of energy gap were decreased from 1.68 to 1.53 eV as the spray time increases from 15 min to 45 min. The nonlinear refractive index of the CoNi2S4 thin films was increased with increasing of the spray time. The CoNi2S4 thin films exhibit single activation energy and the activation energy was decreased as the spray time increased.

Nano-architecture based photoelectrochemical water oxidation efficiency enhancement by CdS photoanodes

NASA Astrophysics Data System (ADS)

Pareek, Alka; Kim, Hyun Gyu; Paik, Pradip; Joardar, Joydip; Borse, Pramod H.

2017-02-01

In the present work, 2D nanostructuring has been utilized to impart an efficiency improvement to the hexagonal phase CdS films for the photoelectrochemical (PEC) cells those were deposited by spray pyrolysis technique. By controlling the aerosol droplet- size, population and impingement time during the spray pyrolysis deposition, various nano-features viz. randomly aligned nanorods, nanotubes and nanowires of CdS has been demonstrated for the first time. A growth mechanism has been proposed to predict the temporal evolution of the nanostructures. The prominent nanoscale structures show improved optical properties in the visible range of solar spectrum. The structural studies validate the morphological differences of nanostructures in terms of the texture coefficient analysis as well as 2D micro x-ray diffraction imaging. Electrochemical characterization is carried out to understand the effect of nanostructuring on the PEC performance of the CdS photoanodes in the sulphide (0.1 M Na2S  +  0.02 M Na2SO3) electrolyte at applied bias of 0.2 V (versus SCE). The evolution of morphology from randomly aligned rods to nanowire is responsible for improved photocurrent (3.5 times). CdS film morphology can be tuned to nanotubes, nano- rose buds and nanorod bunches even by doping Zn2+ ions in CdS lattice. Nano-structuring of doped CdS has shown enhanced performance of the photoanodes. The nanotubes structures yielded highest photocurrent density of 1.6 mA cm-2. Whereas modifying the 2D-nanostructured CdS film by simple MoO3 spray coating yields the photocurrent enhancement to 2.1 mA cm-2.

Sprayed nanostructured TiO2 films for efficient photocatalytic degradation of textile azo dye.

PubMed

Stambolova, Irina; Shipochka, Capital Em Cyrillicaria; Blaskov, Vladimir; Loukanov, Alexandrе; Vassilev, Sasho

2012-12-05

Spray pyrolysis procedure for preparation of nanostructured TiO(2) films with higher photocatalytic effectiveness and longer exploitation life is presented in this study. Thin films of active nanocrystalline TiO(2) were obtained from titanium isopropoxide, stabilized with acetyl acetone and characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The activity of sprayed nanostructured TiO(2) is tested for photocatalytic degradation of Reactive Black 5 dye with concentrations up to 80 ppm. Interesting result of the work is the reduction of toxicity after photocatalytic treatment of RB5 with TiO(2), which was confirmed by the lower percentage of mortality of Artemia salina. It was proved that the film thickness, conditions of post deposition treatment and the type of the substrate affected significantly the photocatalytic reaction. Taking into account that the parameters are interdependent, it is necessary to optimize the preparation conditions in order to synthesize photocatalytic active films. Copyright © 2012 Elsevier B.V. All rights reserved.

Spray Pyrolysis as a Synthetic Tool.

DTIC Science & Technology

1984-11-01

tendency towards insertion into alkyl side chains, this alternative reaction to give oxazolidinones (3) is observed only in a few cases , and then in...dihydrobenzimidazoles and azo-compounds. In some cases , however (X - Ac. COMe. or CN) work-up in methanol solution produces methyl N-arylcarbamates (p-XC*HNH...XC6H4NHCO2Me) are produced. The mechanism of this surprising reaction is discussed. The behaviour of C-(o-azidobenzoyl) derivatives of alkyl ketones and

Effects of RF plasma treatment on spray-pyrolyzed copper oxide films on silicon substrates

NASA Astrophysics Data System (ADS)

Madera, Rozen Grace B.; Martinez, Melanie M.; Vasquez, Magdaleno R., Jr.

2018-01-01

The effects of radio-frequency (RF) argon (Ar) plasma treatment on the structural, morphological, electrical and compositional properties of the spray-pyrolyzed p-type copper oxide films on n-type (100) silicon (Si) substrates were investigated. The films were successfully synthesized using 0.3 M copper acetate monohydrate sprayed on precut Si substrates maintained at 350 °C. X-ray diffraction revealed cupric oxide (CuO) with a monoclinic structure. An apparent improvement in crystallinity was realized after Ar plasma treatment, attributed to the removal of residues contaminating the surface. Scanning electron microscope images showed agglomerated monoclinic grains and revealed a reduction in size upon plasma exposure induced by the sputtering effect. The current-voltage characteristics of CuO/Si showed a rectifying behavior after Ar plasma exposure with an increase in turn-on voltage. Four-point probe measurements revealed a decrease in sheet resistance after plasma irradiation. Fourier transform infrared spectral analyses also showed O-H and C-O bands on the films. This work was able to produce CuO thin films via spray pyrolysis on Si substrates and enhancement in their properties by applying postdeposition Ar plasma treatment.

Highly Sensitive Nanostructured SnO2 Thin Films For Hydrogen Sensing

NASA Astrophysics Data System (ADS)

Patil, L. A.; Shinde, M. D.; Bari, A. R.; Deo, V. V.

2010-10-01

Nanostructured SnO2 thin films were prepared by ultrasonic spray pyrolysis technique. Aqueous solution (0.05 M) of SnCl4ṡ5H2O in double distilled water was chosen as the starting solution for the preparation of the films. The stock solution was delivered to nozzle with constant and uniform flow rate of 70 ml/h by Syringe pump SK5001. Sono-tek spray nozzle, driven by ultrasonic frequency of 120 kHz, converts the solution into fine spray. The aerosol produced by nozzle was sprayed on glass substrate heated at 150 °C. The sensing performance of the films was tested for various gases such as LPG, hydrogen, ethanol, carbon dioxide and ammonia. The sensor (30 min) showed high gas response (S = 3040 at 350 °C) on exposure of 1000 ppm of hydrogen and high selectivity against other gases. Its response time was short (2 s) and recovery was also fast (12 s). To understand reasons behind this uncommon gas sensing performance of the films, their structural, microstructural, and optical properties were studied using X-ray diffraction, electron microscopy (SEM and TEM) respectively. The results are interpreted

Effect of copper and nickel doping on the optical and structural properties of ZnO

NASA Astrophysics Data System (ADS)

Muǧlu, G. Merhan; Sarıtaş, S.; ćakıcı, T.; Şakar, B.; Yıldırım, M.

2017-02-01

The present study is focused on the Cu doped ZnO and Ni doped ZnO dilute magnetic semiconductor thin films. ZnO:Cu and ZnO:Ni thin films were grown by Chemically Spray Pyrolysis (CSP) method on glass substrates. Optical analysis of the films was done spectral absorption and transmittance measurements by UV-Vis double beam spectrophotometer technique. The structure, morphology, topology and elemental analysis of ZnO:Cu and ZnO:Ni dilute magnetic thin films were investigated by X-ray diffraction (XRD), Raman Analysis, field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM) techniques, respectively. Also The magnetic properties of the ZnO:Ni thin film was investigated by vibrating sample magnetometer (VSM) method. VSM measurements of ZnO:Ni thin film showed that the ferromagnetic behavior.

Effect of Mo-doping concentration on the physical behaviour of sprayed ZnO layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reddy, T. Sreenivasulu; Reddy, M. Vasudeva; Reddy, K. T. Ramakrishna, E-mail: ktrkreddy@gmail.com

2015-06-24

Mo-doped zinc oxide layers (MZO) have been prepared on cleaned glass substrates by chemical spray pyrolysis technique by varying Mo-doping concentration in the range, 0 – 5 at. %. The X-ray diffraction studies revealed that all the as prepared layers were polycrystalline in nature and exhibited wurtzite structure. The layers prepared with lower Mo-doping concentration (<2 at. %) were preferably oriented along the (100) plane, whereas in the case of higher Mo-doping concentration (>2 at. %), the films showed the (002) plane as the dominant peak. The optical analysis indicated that all the layers had an average optical transmittance ofmore » 80% in the visible region and the evaluated band gap varied in the range, 3.28 - 3.50 eV.« less

Influences of annealing temperature on sprayed CuFeO2 thin films

NASA Astrophysics Data System (ADS)

Abdelwahab, H. M.; Ratep, A.; Abo Elsoud, A. M.; Boshta, M.; Osman, M. B. S.

2018-06-01

Delafossite CuFeO2 thin films were successfully prepared onto quartz substrates using simple spray pyrolysis technique. Post annealing under nitrogen atmosphere for 2 h was necessary to form delafossite CuFeO2 phase. The effect of alteration in annealing temperature (TA) 800, 850 and 900 °C was study on structural, morphology and optical properties. The XRD results for thin film annealed at TA = 850 °C show single phase CuFeO2 with rhombohedral crystal system and R 3 bar m space group with preferred orientation along (0 1 2). The prepared copper iron oxide thin films have an optical transmission ranged ∼40% in the visible region. The optical direct optical band gap of the prepared thin films was ranged ∼2.9 eV.

Structural, optical and photoelectric properties of sprayed CdS thin films

NASA Astrophysics Data System (ADS)

Chandel, Tarun; Dwivedi, Shailendra Kumar; Zaman, M. Burhanuz; Rajaram, P.

2018-05-01

In this study, CdS thin films were grown via a facile spray pyrolysis technique. The crystalline phase, morphological, compositional and optical properties of the CdS thin films have been studied using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and UV-vis absorption spectroscopy, respectively. XRD patterns show that the grown CdS films crystallized in the hexagonal structure. Scanning electron microscopy (SEM) study shows that the surfaces of the films are smooth and are uniformly covered with nanoparticles. EDAX results reveal that the grown films have good stochiometry. UV-vis spectroscopy shows that the grown films have transparency above 80% over the entire visible region. The photo-electric response of the CdS films grown on glass substrates has been observed.

Gas-phase synthesis of magnetic metal/polymer nanocomposites.

PubMed

Starsich, Fabian H L; Hirt, Ann M; Stark, Wendelin J; Grass, Robert N

2014-12-19

Highly magnetic metal Co nanoparticles were produced via reducing flame spray pyrolysis, and directly coated with an epoxy polymer in flight. The polymer content in the samples varied between 14 and 56 wt% of nominal content. A homogenous dispersion of Co nanoparticles in the resulting nanocomposites was visualized by electron microscopy. The size and crystallinity of the metallic fillers was not affected by the polymer, as shown by XRD and magnetic hysteresis measurements. The good control of the polymer content in the product nanocomposite was shown by elemental analysis. Further, the successful polymerization in the gas phase was demonstrated by electron microscopy and size measurements. The presented effective, dry and scalable one-step synthesis method for highly magnetic metal nanoparticle/polymer composites presented here may drastically decrease production costs and increase industrial yields.

Gas-phase synthesis of magnetic metal/polymer nanocomposites

NASA Astrophysics Data System (ADS)

Starsich, Fabian H. L.; Hirt, Ann M.; Stark, Wendelin J.; Grass, Robert N.

2014-12-01

Highly magnetic metal Co nanoparticles were produced via reducing flame spray pyrolysis, and directly coated with an epoxy polymer in flight. The polymer content in the samples varied between 14 and 56 wt% of nominal content. A homogenous dispersion of Co nanoparticles in the resulting nanocomposites was visualized by electron microscopy. The size and crystallinity of the metallic fillers was not affected by the polymer, as shown by XRD and magnetic hysteresis measurements. The good control of the polymer content in the product nanocomposite was shown by elemental analysis. Further, the successful polymerization in the gas phase was demonstrated by electron microscopy and size measurements. The presented effective, dry and scalable one-step synthesis method for highly magnetic metal nanoparticle/polymer composites presented here may drastically decrease production costs and increase industrial yields.

A comparison study of Co and Cu doped MgO diluted magnetic thin films

NASA Astrophysics Data System (ADS)

Sarıtaş, S.; ćakıcı, T.; Muǧlu, G. Merhan; Kundakcı, M.; Yıldırım, M.

2017-02-01

Transition metal-doped MgO diluted magnetic thin films are appropriate candidates for spintronic applications and designing magnetic devices and sensors. Therefore, MgO:Co and MgO:Cu films were deposited on glass substrates by Chemical Spray Pyrolysis (CSP) method different thin film deposition parameters. Deposited different transition metal doped MgO thin films were compared in terms of optic and structural properties. Comparison optic analysis of the films was investigated spectral absorption and transmittance measurements by UV-Vis double beam spectrophotometer technique. Comparison structural analysis of the thin films was examined by using XRD, Raman Analysis, SEM, EDX and AFM techniques. The transition metal-doped; MgO:Co and MgO:Cu thin films maybe have potential applications in spintronics and magnetic data storage.

Enhanced gas sensing correlated with structural and optical properties of Cs-loaded SnO2 nanofilms

NASA Astrophysics Data System (ADS)

Elia Raine, P. J.; Arun George, P.; Balasundaram, O. N.; Varghese, T.

2016-09-01

The Cs-loaded SnO2 thin films were prepared by the spray pyrolysis technique and were characterized by X-ray diffraction, scanning electron microscopy, ultraviolet-visible spectroscopy, impedance spectroscopy and conductometric method. Investigations based on the structural, optical and electrical properties confirm an enhanced gas sensing potential of cesium-loaded tin oxide films. It is found that the tin oxide thin film doped with 4% Cs with a mean grain size of 20 nm at a deposition temperature of 350 ° C show a maximum sensor response of 97.5% for LPG consistently. It is also observed that the sensor response of Cs-doped SnO2 thin films depends on the dopant concentration and the deposition temperature of the film.

Comparative alternative materials assessment to screen toxicity hazards in the life cycle of CIGS thin film photovoltaics.

PubMed

Eisenberg, Daniel A; Yu, Mengjing; Lam, Carl W; Ogunseitan, Oladele A; Schoenung, Julie M

2013-09-15

Copper-indium-gallium-selenium-sulfide (CIGS) thin film photovoltaics are increasingly penetrating the market supply for consumer solar panels. Although CIGS is attractive for producing less greenhouse gas emissions than fossil-fuel based energy sources, CIGS manufacturing processes and solar cell devices use hazardous materials that should be carefully considered in evaluating and comparing net environmental benefits of energy products. Through this research, we present a case study on the toxicity hazards associated with alternative materials selection for CIGS manufacturing. We applied two numeric models, The Green Screen for Safer Chemicals and the Toxic Potential Indicator. To improve the sensitivity of the model outputs, we developed a novel, life cycle thinking based hazard assessment method that facilitates the projection of hazards throughout material life cycles. Our results show that the least hazardous CIGS solar cell device and manufacturing protocol consist of a titanium substrate, molybdenum metal back electrode, CuInS₂ p-type absorber deposited by spray pyrolysis, ZnS buffer deposited by spray ion layer gas reduction, ZnO:Ga transparent conducting oxide (TCO) deposited by sputtering, and the encapsulant polydimethylsiloxane. Copyright © 2013 Elsevier B.V. All rights reserved.

Photoelectrochemical performance of W-doped BiVO4 thin films deposited by spray pyrolysis

NASA Astrophysics Data System (ADS)

Holland, S. Keith; Dutter, Melissa R.; Lawrence, David J.; Reisner, Barbara A.; DeVore, Thomas C.

2014-01-01

The effects of tungsten doping and hydrogen annealing on the photoelectrochemical (PEC) performance of bismuth vanadate (BiVO4) photoanodes for solar water splitting were studied. Thin films of BiVO were deposited on indium tin oxide-coated glass slides by ultrasonic spray pyrolysis of an aqueous solution containing bismuth nitrate and vanadium oxysulfate. Tungsten doping was achieved by adding either silicotungstic acid (STA) or ammonium metatungstate (AMT) to the precursor. The 1.7- to 2.2-μm-thick films exhibited a highly porous microstructure. Undoped films that were reduced at 375°C in 3% H exhibited the largest photocurrent densities under 0.1 W cm-2 AM1.5 illumination, where photocurrent densities of up to 1.3 mA cm-2 at 0.5 V with respect to Ag/AgCl were achieved. Films doped with 1% or 5% (atomic percent) tungsten from either STA or AMT exhibited reduced PEC performance and greater sample-to-sample performance variations. Powder x-ray diffraction data indicated that the films continue to crystallize in the monoclinic polymorph at low doping levels but crystallize in the tetragonal scheelite structure at higher doping. It is surmised that the phase and morphology differences promoted by the addition of W during the deposition process reduced the PEC performance as measured by photovoltammetry.

Extremely fine structured cathode for solid oxide fuel cells using Sr-doped LaMnO3 and Y2O3-stabilized ZrO2 nano-composite powder synthesized by spray pyrolysis

NASA Astrophysics Data System (ADS)

Shimada, Hiroyuki; Yamaguchi, Toshiaki; Sumi, Hirofumi; Nomura, Katsuhiro; Yamaguchi, Yuki; Fujishiro, Yoshinobu

2017-02-01

A solid oxide fuel cell (SOFC) for high power density operation was developed with a microstructure-controlled cathode using a nano-composite powder of Sr-doped LaMnO3 (LSM) and Y2O3-stabilized ZrO2 (YSZ) synthesized by spray pyrolysis. The individual LSM-YSZ nano-composite particles, formed by crystalline and amorphous nano-size LSM and YSZ particles, showed spherical morphology with uniform particle size. The use of this powder for cathode material led to an extremely fine microstructure, in which all the LSM and YSZ grains (approximately 100-200 nm) were highly dispersed and formed their own network structures. This microstructure was due to the two phase electrode structure control using the powder, namely, nano-order level in each particle and micro-order level between particles. An anode-supported SOFC with the LSM-YSZ cathode using humidified H2 as fuel and ambient air as oxidant exhibited high power densities, such as 1.29 W cm-2 under a voltage of 0.75 V and a maximum power density of 2.65 W cm-2 at 800 °C. Also, the SOFC could be stably operated for 250 h with no degradation, even at a high temperature of 800 °C.

Fullerene-like MoSe2 nanoparticles-embedded CNT balls with excellent structural stability for highly reversible sodium-ion storage

NASA Astrophysics Data System (ADS)

Choi, Seung Ho; Kang, Yun Chan

2016-02-01

Three-dimensional (3D) porous-structured carbon nanotube (CNT) balls embedded with fullerene-like MoSe2 nanocrystals were successfully prepared by the spray pyrolysis process and subsequent selenization process. The MoO2-CNT composite balls prepared by spray pyrolysis transformed into the fullerene-like MoSe2/CNT (F-MoSe2/CNT) composite balls by the selenization process. The F-MoSe2/CNT composite balls exhibited superior sodium-ion storage properties to bare MoSe2 and MoSe2/CNT with a filled structure (N-MoSe2/CNT), both of which were prepared as comparison samples. The 250th discharge capacities of bare MoSe2, N-MoSe2/CNT composite balls, and F-MoSe2/CNT composite balls were 144, 200, and 296 mA h g-1, respectively, at a high current density of 1.0 A g-1, and their capacity retentions measured from the second cycle were 37%, 66%, and 83%, respectively. The 10th discharge capacities of the F-MoSe2/CNT composite balls were 382, 346, 310, 280, and 255 mA h g-1 at current densities of 0.2, 0.5, 1.5, 3.0, and 5.0 A g-1, respectively. The synergetic effect of the fullerene-like MoSe2 nanocrystals with ultrafine sizes and the CNT balls with a tangled and 3D porous structure and high electrical conductivity resulted in excellent sodium-ion storage properties of the F-MoSe2/CNT composite balls.Three-dimensional (3D) porous-structured carbon nanotube (CNT) balls embedded with fullerene-like MoSe2 nanocrystals were successfully prepared by the spray pyrolysis process and subsequent selenization process. The MoO2-CNT composite balls prepared by spray pyrolysis transformed into the fullerene-like MoSe2/CNT (F-MoSe2/CNT) composite balls by the selenization process. The F-MoSe2/CNT composite balls exhibited superior sodium-ion storage properties to bare MoSe2 and MoSe2/CNT with a filled structure (N-MoSe2/CNT), both of which were prepared as comparison samples. The 250th discharge capacities of bare MoSe2, N-MoSe2/CNT composite balls, and F-MoSe2/CNT composite balls were 144, 200, and 296 mA h g-1, respectively, at a high current density of 1.0 A g-1, and their capacity retentions measured from the second cycle were 37%, 66%, and 83%, respectively. The 10th discharge capacities of the F-MoSe2/CNT composite balls were 382, 346, 310, 280, and 255 mA h g-1 at current densities of 0.2, 0.5, 1.5, 3.0, and 5.0 A g-1, respectively. The synergetic effect of the fullerene-like MoSe2 nanocrystals with ultrafine sizes and the CNT balls with a tangled and 3D porous structure and high electrical conductivity resulted in excellent sodium-ion storage properties of the F-MoSe2/CNT composite balls. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07733h

The role of Mg dopant on the morphological, structural and optical properties of Mg doped zinc oxide grown through hydrothermal method

NASA Astrophysics Data System (ADS)

Susetyo, P.; Fauzia, V.; Sugihartono, I.

2017-04-01

ZnO nanorods is a low cost II-VI semiconductor compound with huge potential to be applied in optoelectronic devices i.e. light emitting diodes, solar cells, gas sensor, spintronic devices and lasers. In order to improve the electrical and optical properties, group II, III and IV elements were widely investigated as dopand elements on ZnO. In this work, magnesium (Mg) was doped into ZnO nanorods. Samples were prepared firstly by deposition of undoped ZnO seed layer on indium thin oxide coated glass substrates by ultrasonic spray pyrolysis method and then followed by the growth of ZnO nanorods doped by three different Mg concentrations by hydrothermal method. Based on the morphological, microstructural and optical characterizations results, it is concluded that the increase of magnesium concentration tends to reduce the diameter of ZnO nanorods, increases the bandgap energy and decreases the UV absorption the luminescence in UV and visible range.

Study of the optical properties of CuAlS2 thin films prepared by two methods

NASA Astrophysics Data System (ADS)

Ahmad, S. M.

2017-04-01

CuAlS2 thin films were successfully deposited on glass substrates using two methods: chemical spray pyrolysis (CSP) and chemical bath deposition (CBD). It was confirmed from the X-ray diffraction (XRD) analysis that CSP films exhibited a polycrystalline nature while amorphous nature was diagnosed for CBD films. Also XRD analysis was utilized to compute grain size, strain and dislocation density. Surface morphology was characterized using scanning electron microscope and photomicroscope images. The optical absorption measurement revealed that the direct allowed electronic transition with band gaps 2.8 eV and 3.0 eV for CBD and CSP methods, respectively. The optical constants, such as extinction coefficient ( k), refractive index ( n), real and imaginary dielectric constants ( ɛ 1, ɛ 2) were discussed. The photoluminescence (PL) spectra of CuAlS2 thin films appeared as a single peak for each of them, and this is attributed to band-to-band transition.

CORRIGENDUM: The growth of aligned carbon nanotubes on quartz substrate by spray pyrolysis of hexane

NASA Astrophysics Data System (ADS)

Sadeghian, Zahra

2008-07-01

Some of the text in this paper was copied directly from other papers cited by the author. Whilst this does not affect the scientific content and is therefore not scientific plagiarism, the author acknowledges that such usage of text attributed and copyrighted to other unrelated authors is unacceptable practice. Reference [21] in the paper should read: [21] Afre R A, Soga T, Jimbo T, Kumar M, Ando Y and Sharon M 2005 Chem. Phys. Lett. 414 6-10

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skariah, Benoy, E-mail: skariahbenoy@yahoo.co.in, E-mail: dr.boben1@gmail.com; Thomas, Boben, E-mail: skariahbenoy@yahoo.co.in, E-mail: dr.boben1@gmail.com

For LPG sensing, boron doped (0.2 to 0.8 wt. %) polycrystalline tin oxide thin films are deposited by spray pyrolysis in the temperature range 325 - 430 °C. Sensor response of 56 % is achieved for 1000 ppm of LPG, at an operating temperature of 350 °C. The effects of ageing under ambient conditions on the sensor response are investigated for a storage period of six years. Ageing increases the film resistance but the gas response is lowered. XRD, SEM, FESEM, FTIR and XPS are utilized for structural, morphological and compositional charaterisations.

NOx formation from the combustion of monodisperse n-heptane sprays doped with fuel-nitrogen additives

NASA Technical Reports Server (NTRS)

Sarv, Hamid; Cernansky, Nicholas P.

1989-01-01

A series of experiments with simulated synthetic fuels were conducted in order to investigate the effect of droplet size on the conversion of fuel-nitrogen to NOx. Pyridine and pyrrole were added to n-heptane as nitrogen-containing additives and burned as monodisperse fuel droplets under various operating conditions in a spray combustion facility. The experimental results indicate that under stoichiometric and fuel-rich conditions, reducing the droplet size increases the efficiency of fuel-N conversion to NOx. This observation is associated with improved oxidation of the pyrolysis fragments of the additive by better oxygen penetration through the droplet flame zone. The dominant reactions by which fuel-N is transformed to NOx were also considered analytically by a premixed laminar flame code. The calculations are compared to the small droplet size results.

Spray pyrolytic deposition of α-MoO3 film and its use in dye-sensitized solar cell

NASA Astrophysics Data System (ADS)

Tamboli, Parvin S.; Jagtap, Chaitali V.; Kadam, Vishal S.; Ingle, Ravi V.; Vhatkar, Rajiv S.; Mahajan, Smita S.; Pathan, Habib M.

2018-04-01

Thermal decomposition of ammonium para molybdate tetrahydrate precursor has been studied to determine degradation temperatures in air atmosphere. Current work explores the synthesis of α-MoO3 films by an economical spray pyrolysis technique using ammonium para molybdate tetrahydrate precursor in the presence of compressed air. A variety of characterization techniques such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-visible spectroscopy, Fourier transform infrared, and Raman spectroscopy were carried out, and the studies have confirmed that orthorhombic phase formation of MoO3 takes place with spongy mesh-type structure. The study of electro-catalytic activity of α-MoO3 in titania-based dye-sensitized solar cell is also carried out by cyclic voltammetry, electrochemical impedance spectroscopy, and Tafel curves to evaluate its performance as a counter electrode.

Low oxygen biomass-derived pyrolysis oils and methods for producing the same

DOEpatents

Marinangeli, Richard; Brandvold, Timothy A; Kocal, Joseph A

2013-08-27

Low oxygen biomass-derived pyrolysis oils and methods for producing them from carbonaceous biomass feedstock are provided. The carbonaceous biomass feedstock is pyrolyzed in the presence of a catalyst comprising base metal-based catalysts, noble metal-based catalysts, treated zeolitic catalysts, or combinations thereof to produce pyrolysis gases. During pyrolysis, the catalyst catalyzes a deoxygenation reaction whereby at least a portion of the oxygenated hydrocarbons in the pyrolysis gases are converted into hydrocarbons. The oxygen is removed as carbon oxides and water. A condensable portion (the vapors) of the pyrolysis gases is condensed to low oxygen biomass-derived pyrolysis oil.

Methods for deoxygenating biomass-derived pyrolysis oil

DOEpatents

Brandvold, Timothy A.

2015-07-14

Methods for deoxygenating a biomass-derived pyrolysis oil are provided. A method comprising the steps of diluting the biomass-derived pyrolysis oil with a phenolic-containing diluent to form a diluted pyoil-phenolic feed is provided. The diluted pyoil-phenolic feed is contacted with a deoxygenating catalyst in the presence of hydrogen at hydroprocessing conditions effective to form a low-oxygen biomass-derived pyrolysis oil effluent.

Effect of Heat and Laser Treatment on Cu2S Thin Film Sprayed on Polyimide Substrate

NASA Astrophysics Data System (ADS)

Magdy, Wafaa; Mahmoud, Fawzy A.; Nassar, Amira H.

2018-02-01

Three samples of copper sulfide Cu2S thin film were deposited on polyimide substrate by spray pyrolysis using deposition temperature of 400°C and deposition time of about 45 min. One of the samples was left as deposited, another was heat treated, while the third was laser treated. The structural, surface morphological, optical, mechanical, and electrical properties of the films were investigated. X-ray diffraction (XRD) analysis showed that the copper sulfide films were close to copper-rich phase (Cu2S). Increased crystallite size after heat and laser treatment was confirmed by XRD analysis and scanning electron microscopy. Vickers hardness measurements showed that the samples' hardness values were enhanced with increasing crystallite size, representing an inverse Hall-Petch (H-P) effect. The calculated optical bandgap of the treated films was lower than that of the deposited film. Finally, it was found that both heat and laser treatment enhanced the physical properties of the sprayed Cu2S films on polyimide substrate for use in solar energy applications.

Spray pyrolysed Ru:TiO2 thin film electrodes prepared for electrochemical supercapacitor

NASA Astrophysics Data System (ADS)

Fugare, B. Y.; Thakur, A. V.; Kore, R. M.; Lokhande, B. J.

2018-04-01

Ru doped TiO2 thin films are prepared by using 0.06 M aqueous solution of potassium titanium oxalate (pto), and 0.005 M aqueous solution of ruthenium tri chloride (RuCl3) precursors. The deposition was carried on stainless steel (SS) by using well known ultrasonic spray pyrolysis technique (USPT) at 723° K by maintaining the spray rate 12 cc/min and compressed air flow rate 10 Lmin-1. Prepared Ru:TiO2 thin films were characterized by structurally, morphologically and electrochemically. Deposited RuO2 shows amorphous structure and TiO2 shows tetragonal crystal structure with rutile as prominent phase at very low decomposition temperature. SEM micrographs of RuO2 exhibits porous, interconnected, spherical grains type morphology and TiO2 shows porous, nanorods and nanoplates like morphology and also Ru doped TiO2 shows porous, spherical, granular and nanorods type morphology. The electrochemical cyclic voltammetery shows mixed capacitive behavior. The achieved highest value of specific capacitance 2692 F/g was Ru doped TiO2 electrode in 0.5 M H2SO4.

In Situ TiC-Reinforced Ni-Based Composite Coating Prepared by Flame Spraying Using Sucrose as the Source of Carbon

NASA Astrophysics Data System (ADS)

Wang, Haitao; Zhang, Shouquan; Zhu, Jinglei; Huang, Jihua; Liu, Huiyuan; Zhang, Hua

2009-03-01

A Ni-Ti-C composite powder for Reactive Thermal Spraying is made by heating a mixture of titanium, nickel, and sucrose to carbonize the sucrose, which is used as the source of carbon. The carbon obtained by pyrolysis of sucrose is a reactive constituent as well as the binder in the composite powder. The titanium and nickel particles are bound by the carbon to form granules of the composite powder. This powder feedstock was used to prepare in situ TiC-reinforced Ni-based composite coating by oxyacetylene flame spraying. The TiC-Ni composite coating is made of TiC, Ni, and some Ni3Ti. In the coating, a mass of fine TiC particles is uniformly distributed within the metallic matrix. The microhardness and surface hardness of the coating are, respectively, 1433 HV0.2kg and 62 ± 6 (HR30N). The wear resistance is much better for the TiC-Ni composite coating than for the substrate and Ni60 coating.

Ultraviolet/visible photodiode of nanostructure Sn-doped ZnO/Si heterojunction

NASA Astrophysics Data System (ADS)

Kheirandish, N.; Mortezaali, A.

2013-05-01

Sn doped ZnO nanostructures deposited on Si substrate with (100) orientation by spray pyrolysis method at temperature 450 °C. Sn/Zn atomic ratio varies from 0% to 5%. The scanning electron microscope measurements showed that size of particles reduce with increasing the doping concentration. The X-ray diffraction analysis revealed formation of the wurtzite phase of ZnO. I-V curves of Sn doped ZnO/Si were investigated in dark and shows diode-like rectifying behavior. Among doped ZnO/Si, sample with atomic ratio of Sn/Zn = 5% is a good candidate to study photodiode properties in UV/visible range. Photoelectric effects have been observed under illumination monochromatic laser light with a wavelength of 325 nm and halogen lamp. Measurements demonstrate that the photodiode has high sensitivity and reproducibility to halogen light respect to laser light.

Methods for deoxygenating biomass-derived pyrolysis oil

DOEpatents

Baird, Lance Awender; Brandvold, Timothy A.

2015-06-30

Methods for deoxygenating a biomass-derived pyrolysis oil are provided. A method for deoxygenating a biomass-derived pyrolysis oil comprising the steps of combining a biomass-derived pyrolysis oil stream with a heated low-oxygen-pyoil diluent recycle stream to form a heated diluted pyoil feed stream is provided. The heated diluted pyoil feed stream has a feed temperature of about 150.degree. C. or greater. The heated diluted pyoil feed stream is contacted with a first deoxygenating catalyst in the presence of hydrogen at first hydroprocessing conditions effective to form a low-oxygen biomass-derived pyrolysis oil effluent.

Development of SnS (FTO/CdS/SnS) thin films by nebulizer spray pyrolysis (NSP) for solar cell applications

NASA Astrophysics Data System (ADS)

Arulanantham, A. M. S.; Valanarasu, S.; Jeyadheepan, K.; Ganesh, V.; Shkir, Mohd

2018-01-01

Herein we report a well-organized analysis on various key-properties of SnS thin films for solar cell fabricated by nebulizer spray pyrolysis technique. X-ray diffraction study reveals the polycrystalline nature of deposited films with orthorhombic crystal structure. The crystallite size was calculated and observed to be in the range of 8-28 nm with increasing molarity of precursor solution. The stoichiometry composition of SnS was confirmed by EDX study. SEM/AFM studies divulge the well-covered deposited surface with spherical grains and the size of grains is increasing with concentration and so the roughness. A remarkable decrease in band gap from 2.6 eV to 1.6 eV was noticed by raising the molar concentration from 0.025 M up to 0.075 M. A single strong emission peak at about 825 nm is observed in PL spectra with enhanced intensity which may be attributed to near band edge emission. From the Hall effect measurement, it was found that the SnS thin film exhibits p-type conductivity. The calculated values of resistivity and carrier concentration are 0.729 Ω cm and 3.67 × 1018/cm3 respectively. Furthermore, to study the photovoltaic properties of SnS thin films a heterojunction solar cell, FTO/n-CdS/p-SnS was produced and the conversion efficiency was recorded about 0.01%.

Influence of precursor concentration on physical properties of CdO thin films prepared by spray pyrolysis technique using nebulizer

NASA Astrophysics Data System (ADS)

Anitha, M.; Amalraj, L.; Anitha, N.

2017-12-01

Cadmium oxide (CdO) thin films were prepared with different concentrations of precursor solution (0.05, 0.1, 0.15, 0.2 and 0.25 M, respectively) at the optimized temperature (200 °C) using the nebulized spray pyrolysis technique to obtain better crystallinity in polycrystalline thin films on amorphous glass substrates. The XRD characterization of those samples revealed a preferential orientation along the (111) plane having a cubic structure. The scanning electron microscopy (SEM) analysis displayed that all the as-deposited thin films have spherical shaped grains. The transmittance of the as-deposited CdO thin films had decreased from 88 to 71% for longer wavelength regions (600-900 nm) as the precursor concentration had increased and then increased for higher precursor concentration. The optical band gap was found to lie between 2.45 and 2.40 eV belonging to direct transition for those thin films. The presence of Cd-O bond (540 cm-1) was confirmed by FTIR spectrum. The emission properties of CdO thin films were studied by luminescence spectrum recorded at room temperature. A maximum carrier concentration and minimum resistivity values of 4.743 × 1019 cm- 3 and 1.06 × 10-3 Ω-cm, respectively, were obtained for 0.2 M precursor concentration. These CdO thin films have high optical transmittance and high room temperature conductivity, which can be used as the TCO and Solar cell (window layer) material.

A compact skeletal mechanism for n -dodecane with optimized semi-global low-temperature chemistry for diesel engine simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yao, Tong; Pei, Yuanjiang; Zhong, Bei-Jing

A skeletal mechanism with 54 species and 269 reactions was developed to predict pyrolysis and oxidation of n-dodecane as a diesel fuel surrogate involving both high-temperature (high-T) and low-temperature (low-T) conditions. The skeletal mechanism was developed from a semi-detailed mechanism developed at the University of Southern California (USC). Species and reactions for high-T pyrolysis and oxidation of C5-C12 were reduced by using reaction flow analysis (RFA), isomer lumping, and then merged into a skeletal C0-C4 core to form a high-T sub-mechanism. Species and lumped semi-global reactions for low-T chemistry were then added to the high-T sub-mechanism and a 54-species skeletalmore » mechanism is obtained. The rate parameters of the low-T reactions were tuned against a detailed mechanism by the Lawrence Livermore National Laboratory (LLNL), as well as the Spray A flame experimental data, to improve the prediction of ignition delay at low-T conditions, while the high-T chemistry remained unchanged. The skeletal mechanism was validated for auto-ignition, perfectly stirred reactors (PSR), flow reactors and laminar premixed flames over a wide range of flame conditions. The skeletal mechanism was then employed to simulate three-dimensional turbulent spray flames at compression ignition engine conditions and validated against experimental data from the Engine Combustion Network (ECN).« less

An enhancement of photoluminescence property of Ag doped La2O3 thin films at room temperature

NASA Astrophysics Data System (ADS)

Jbeli, R.; Boukhachem, A.; Ben Jemaa, I.; Mahdhi, N.; Saadallah, F.; Elhouichet, H.; Alleg, S.; Amlouk, M.; Ezzaouïa, H.

2017-09-01

Metal transition doped oxide thin films or nanocomposites have recently emerged at the forefront of potentials research. With the focus mainly on efficiency, the aspect of stability against optical irradiation of such materials has so far not been thoroughly addressed. This work covers the synthesis of silver doped lanthanum oxide thin films (La2O3:Ag) which have been prepared by the spray pyrolysis technique on glass substrates at 460 °C. Then, Ag thin films were grown on lanthanum oxide thin films by thermal evaporation. The present work aims to reach the synthesis of La2O3:Ag thin films using both the spray pyrolysis and thermal evaporation techniques. First, X-ray diffraction analysis shows that undoped and Ag doped films crystallize in a mixture of hexagonal and cubic phase with crystallites oriented along (001) direction. Raman spectroscopy shows the bands positions corresponding to hexagonal and cubic phases. On the other hand, an attempt regarding their optical properties has been carried out by means of photoluminescence measurements. Second, from electrical conductivity measurements, the activation energy decreases from 1.42 to 1.09 eV with the increase of annealing time and the charge carriers are following the CBH model as dominant charge transport mechanism. Finally, the annealing time influences the surface wettability property and transforms La2O3 character from hydrophobic (θ > 90°) to hydrophilic (θ < 90°).

CTAB assisted growth and characterization of nanocrystalline CuO films by ultrasonic spray pyrolysis technique

NASA Astrophysics Data System (ADS)

Singh, Iqbal; Kaur, Gursharan; Bedi, R. K.

2011-09-01

An aqueous solution of cupric nitrate trihydrate (Cu(NO 3) 2·3H 2O) modified with cetyltrimetylammonium bromide (CTAB) is used to deposit CuO films on glass substrate by chemical spray pyrolysis technique. The thermal analysis shows that the dried CTAB doped precursor decomposes by an exothermic reaction and suggests that minimum substrate temperature for film deposition should be greater than 270 °C. X-ray diffraction (XRD) studies indicate the formation of monoclinic CuO with preferential orientation along (0 0 2) plane for all film samples. The CTAB used as cationic surfactant in precursor results in the suppression of grain growth in films along the (1 1 0), (0 2 0) and (2 2 0) crystal planes of CuO. Surfactant modified films showed an increase in crystallite size of 14 nm at substrate temperature of 300 °C. The scanning electron micrographs (FESEM) confirm the uniform distribution of facets like grains on the entire area of substrate. CTAB modified films show a significant reduction in the particle agglomeration. Electrical studies of the CuO films deposited at substrate temperature of 300 °C with and without surfactant reveal that the CTAB doping increase the activation energy of conduction by 0.217 eV and room temperature response to ammonia by 9%. The kinetics of the ammonia gas adsorption on the film surface follows the Elovich and Diffusion models.

Photoelectrochemical performance of W-doped BiVO4 thin-films deposited by spray pyrolysis

NASA Astrophysics Data System (ADS)

Holland, Stephen K.; Dutter, Melissa R.; Lawrence, David J.; Reisner, Barbara A.; DeVore, Thomas C.

2013-09-01

The effect of tungsten doping and hydrogen annealing treatments on the photoelectrochemical (PEC) performance of bismuth vanadate (BiVO4) photoanodes for solar water splitting was studied. Thin films of BiVO4 were deposited on ITO-coated glass slides by ultrasonic spray pyrolysis of an aqueous solution containing bismuth nitrate and vanadium oxysulfate. Tungsten doping was achieved by adding either silicotungstic acid (STA) or ammonium metatungstate (AMT) in the aqueous precursor. The 1.7 μm - 2.2 μm thick films exhibited a highly porous microstructure. Undoped films that were reduced at 375 ºC in 3% H2 exhibited the largest photocurrent densities under 0.1 W cm-2 AM1.5 illumination. This performance enhancement was believed to be due to the formation of oxygen vacancies, which are shallow electron donors, in the films. Films doped with 1% or 5% tungsten from either STA or AMT exhibited reduced photoelectrochemical performance and greater sample-to-sample performance variations. Powder X-ray diffraction data of the undoped films indicated that they were comprised primarily of the monoclinic scheelite phase while unidentified phases were also present. Scanning electron microscopy showed slightly different morphology characteristics for the Wdoped films. It is surmised that the addition of W in the deposition process promoted the morphology differences and the formation of different phases, thus reducing the PEC performance of the photoanode samples. Significant PEC performance variability was also observed among films deposited using the described process.

An enhancement of photoluminescence property of Ag doped La2O3 thin films at room temperature.

PubMed

Jbeli, R; Boukhachem, A; Ben Jemaa, I; Mahdhi, N; Saadallah, F; Elhouichet, H; Alleg, S; Amlouk, M; Ezzaouïa, H

2017-09-05

Metal transition doped oxide thin films or nanocomposites have recently emerged at the forefront of potentials research. With the focus mainly on efficiency, the aspect of stability against optical irradiation of such materials has so far not been thoroughly addressed. This work covers the synthesis of silver doped lanthanum oxide thin films (La 2 O 3 :Ag) which have been prepared by the spray pyrolysis technique on glass substrates at 460°C. Then, Ag thin films were grown on lanthanum oxide thin films by thermal evaporation. The present work aims to reach the synthesis of La 2 O 3 :Ag thin films using both the spray pyrolysis and thermal evaporation techniques. First, X-ray diffraction analysis shows that undoped and Ag doped films crystallize in a mixture of hexagonal and cubic phase with crystallites oriented along (001) direction. Raman spectroscopy shows the bands positions corresponding to hexagonal and cubic phases. On the other hand, an attempt regarding their optical properties has been carried out by means of photoluminescence measurements. Second, from electrical conductivity measurements, the activation energy decreases from 1.42 to 1.09eV with the increase of annealing time and the charge carriers are following the CBH model as dominant charge transport mechanism. Finally, the annealing time influences the surface wettability property and transforms La 2 O 3 character from hydrophobic (θ>90°) to hydrophilic (θ<90°). Copyright © 2017 Elsevier B.V. All rights reserved.

Carbon isotope analyses of n-alkanes released from rapid pyrolysis of oil asphaltenes in a closed system.

PubMed

Chen, Shasha; Jia, Wanglu; Peng, Ping'an

2016-08-15

Carbon isotope analysis of n-alkanes produced by the pyrolysis of oil asphaltenes is a useful tool for characterizing and correlating oil sources. Low-temperature (320-350°C) pyrolysis lasting 2-3 days is usually employed in such studies. Establishing a rapid pyrolysis method is necessary to reduce the time taken for the pretreatment process in isotope analyses. One asphaltene sample was pyrolyzed in sealed ampoules for different durations (60-120 s) at 610°C. The δ(13) C values of the pyrolysates were determined by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). The molecular characteristics and isotopic signatures of the pyrolysates were investigated for the different pyrolysis durations and compared with results obtained using the normal pyrolysis method, to determine the optimum time interval. Several asphaltene samples derived from various sources were analyzed using this method. The asphaltene pyrolysates of each sample were similar to those obtained by the flash pyrolysis method on similar samples. However, the molecular characteristics of the pyrolysates obtained over durations longer than 90 s showed intensified secondary reactions. The carbon isotopic signatures of individual compounds obtained at pyrolysis durations less than 90 s were consistent with those obtained from typical low-temperature pyrolysis. Several asphaltene samples from various sources released n-alkanes with distinct carbon isotopic signatures. This easy-to-use pyrolysis method, combined with a subsequent purification procedure, can be used to rapidly obtain clean n-alkanes from oil asphaltenes. Carbon isotopic signatures of n-alkanes released from oil asphaltenes from different sources demonstrate the potential application of this method in 'oil-oil' and 'oil-source' correlations. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Reliable Characterization for Pyrolysis Bio-Oils Leads to Enhanced

Science.gov Websites

Upgrading Methods | NREL Reliable Characterization for Pyrolysis Bio-Oils Leads to Enhanced Upgrading Methods Science and Technology Highlights Highlights in Research & Development Reliable Characterization for Pyrolysis Bio-Oils Leads to Enhanced Upgrading Methods Key Research Results Achievement As co

Synthesis of length-controlled aerosol carbon nanotubes and their dispersion stability in aqueous solution.

PubMed

Moon, Young Kyun; Lee, Jaebeom; Lee, Jae Keun; Kim, Tae Kyu; Kim, Soo H

2009-02-03

A one-step method combining spray pyrolysis and thermal chemical vapor deposition (CVD) processes was developed to grow hybrid carbon nanotube (CNT)-bimetallic composite particles. Nickel, aluminum, and acetylene were used as the catalytic site, noncatalytic matrix, and hydrocarbon source, respectively. The bimetallic particles (i.e., Al-Ni) were spray pyrolized and subsequently passed through thermal CVD. During the thermal CVD, the catalytic decomposition of acetylene occurred on the free-floating bimetallic particles so that sea urchin-like CNTs were radially grown. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses revealed the CNTs to have a uniform diameter of approximately 10 +/- 2 nm. The length of the CNTs was controlled by varying the residence time of the bimetallic nanoparticles with a length of 200-1000 nm. After nitric acid treatment, the CNTs were released by melting the bimetallic particles. The resulting CNTs were then dispersed in an aqueous solution to examine the effect of the length of CNTs on their dispersion stability, which is a critical issue for the stability and repeatability of the heat transfer performance in nanofluids. Ultraviolet-visible (UV-vis) spectrometer analysis showed that shorter CNTs were less stable than the longer CNTs due to the higher mobility-induced agglomeration of the shorter CNTs.

The Use of Spray-Dried Mn₃O₄/C Composites as Electrocatalysts for Li-O₂ Batteries.

PubMed

Yang, Hong-Kai; Chin, Chih-Chun; Chen, Jenn-Shing

2016-11-07

The electrocatalytic activities of Mn₃O₄/C composites are studied in lithium-oxygen (Li-O₂) batteries as cathode catalysts. The Mn₃O₄/C composites are fabricated using ultrasonic spray pyrolysis (USP) with organic surfactants as the carbon sources. The physical and electrochemical performance of the composites is characterized by X-ray diffraction, scanning electron microscopy, particle size analysis, Brunauer-Emmett-Teller (BET) measurements, elemental analysis, galvanostatic charge-discharge methods and rotating ring-disk electrode (RRDE) measurements. The electrochemical tests demonstrate that the Mn₃O₄/C composite that is prepared using Trition X-114 (TX114) surfactant has higher activity as a bi-functional catalyst and delivers better oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalytic performance in Li-O₂ batteries because there is a larger surface area and particles are homogeneous with a meso/macro porous structure. The rate constant ( k f ) for the production of superoxide radical (O₂ • - ) and the propylene carbonate (PC)-electrolyte decomposition rate constant ( k ) for M₃O₄/C and Super P electrodes are measured using RRDE experiments and analysis in the 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF₆)/PC electrolyte. The results show that TX114 has higher electrocatalytic activity for the first step of ORR to generate O₂ • - and produces a faster PC-electrolyte decomposition rate.

Effect of variation in indium concentration on the photosensitivity of chlorine doped In{sub 2}S{sub 3} thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cherian, Angel Susan; Kartha, C. Sudha; Vijayakumar, K. P.

2014-01-28

Consequence of variation in Indium concentration in chlorine doped In2S{sub 3} thin films deposited by spray pyrolysis technique was studied. Chlorine was incorporated in the spray solution, using HCl and Indium concentration was varied by adjusting In/S ratio Interestingly, the photo response of all chlorine doped samples augmented compared to pristine samples; but the highest photosensitivity value of ∼2300 was obtained only when 36ml 0.5M HCl was added to the solution of In{sub 2}S{sub 3} having In/S=2/8. It was also observed that samples with high photosensitivity possess higher band gap and variation in sub band gap absoption levels were observedmore » with increase in Indium concentration. The present study proved that concentration of Indium plays an important role in controlling the crystallinity and photosensitivity of chlorine doped samples.« less

Spray pyrolyzed Cu2SnS3 thin films for photovoltaic application

NASA Astrophysics Data System (ADS)

Patel, Biren; Waldiya, Manmohansingh; Pati, Ranjan K.; Mukhopadhyay, Indrajit; Ray, Abhijit

2018-05-01

We report the fabrication of Cu2SnS3 (CTS) thin films by a non-vacuum and low cost spray pyrolysis technique. Annealing of the as-deposited film in the sulphur atmosphere produces highly stoichiometric, granular and crystalline CTS phase. The CTS thin films shows direct optical band gap of 1.58 eV with high absorption coefficient of 105 cm-1. Hall measurement shows the carrier concentration of the order of 1021 cm-3 and a favourable resistivity of 10-3 Ω cm. A solar cell architecture of Glass/FTO/CTS/CdS/Al:ZnO/Al was fabricated and its current-voltage characteristic shows an open circuit voltage, short circuit current density and fill-factor of 12.6 mV, 20.2 µA/cm2 and 26% respectively. A further improvement in the solar cell parameters is underway.

Effect of swift heavy ion irradiation on structural, optical and electrical properties of spray deposited CdO thin films

NASA Astrophysics Data System (ADS)

Kumaravel, R.; Ramamurthi, K.; Sulania, Indra; Asokan, K.; Kanjilal, D.; Avasti, D. K.; Kulria, P. K.

2011-03-01

Thin films of cadmium oxide have been deposited on glass substrate using the spray pyrolysis technique. The prepared films are irradiated with 120 MeV swift Ag 9+ ions for fluence in the range of 1×10 12-1×10 13 ions cm -2 and their structural properties are studied by glancing angle X-ray diffraction. The films exhibit cubic crystal structure. It is observed that the irradiated films are amorphized at higher fluence of 1×10 13 ions cm -2. Surface morphology studies by atomic force microscopy show that the pristine film has a surface roughness of 39.80 nm and it decreases with increase in ion fluence. The optical transmittance spectra show a decrease in transmittance with increase in fluence and the band gap value also decreases due to irradiation.

Investigation of photocalalytic activity of ZnO prepared by spray pyrolis with various precursors

NASA Astrophysics Data System (ADS)

Bourfaa, F.; Lamri Zeggar, M.; A, A.; Aida, M. S.; Attaf, N.

2016-03-01

Semiconductor photocatalysts such as ZnO has attracted much attention in recent years due to their various applications for the degradation of organic pollutants in water, air and in dye sensitized photovoltaic solar cell. In the present work, ZnO thin films were prepared by ultrasonic spray pyrolysis by using different precursors namely: acetate, chloride and zinc nitrate in order to investigate their influence on ZnO photocatalytic activity. The films crystalline structure was studied by mean of X- ray diffraction measurements (XRD) and the films surface morphology by Scanning Electron Microscopy (SEM). The films optical properties were studied by mean of UV-visible spectroscopy. The prepared films were tested for the degradation of the red reactive dye largely used in textile industry. As a result, we found that the zinc nitrate is the best precursor to prepare ZnO thin films suitable for a good photocatalytic activity.

Source and Biological Response of Biochar Organic Compounds Released into Water; Relationships with Bio-Oil Composition and Carbonization Degree.

PubMed

Ghidotti, Michele; Fabbri, Daniele; Mašek, Ondřej; Mackay, Colin Logan; Montalti, Marco; Hornung, Andreas

2017-06-06

Water-soluble organic compounds (WSOCs) were extracted from corn stalk biochar produced at increasing pyrolysis temperatures (350-650 °C) and from the corresponding vapors, collected as bio-oil. WSOCs were characterized by gas chromatography (semivolatile fraction), negative electron spray ionization high resolution mass spectrometry (hydrophilic fraction) and fluorescence spectroscopy. The pattern of semivolatile WSOCs in bio-oil was dominated by aromatic products from lignocellulose, while in biochar was featured by saturated carboxylic acids from hemi/cellulose and lipids with concentrations decreasing with decreasing H/C ratios. Hydrophilic species in poorly carbonized biochar resembled those in bio-oil, but the increasing charring intensity caused a marked reduction in the molecular complexity and degree of aromaticity. Differences in the fluorescence spectra were attributed to the predominance of fulvic acid-like structures in biochar and lignin-like moieties in bio-oil. The divergence between pyrolysis vapors and biochar in the distribution of WSOCs with increasing carbonization was explained by the hydrophobic carbonaceous matrix acting like a filter favoring the release into water of carboxylic and fulvic acid-like components. The formation of these structures was confirmed in biochar produced by pilot plant pyrolysis units. Biochar affected differently shoot and root length of cress seedlings in germination tests highlighting its complex role on plant growth.

Catalytic co-pyrolysis of cellulose and polypropylene over all-silica mesoporous catalyst MCM-41 and Al-MCM-41.

PubMed

Chi, Yongchao; Xue, Junjie; Zhuo, Jiankun; Zhang, Dahu; Liu, Mi; Yao, Qiang

2018-08-15

Fast pyrolysis is one of the most economical and efficient technologies to convert biomass to bio-oil and valuable chemical products. Co-pyrolysis with hydrogen rich materials such as plastics over zeolite catalysts is one of the significant solutions to various problems of bio-oil such as high oxygen content, low heat value and high acid content. This paper studied pyrolysis of cellulose and polypropylene (PP) separately and co-pyrolysis of cellulose and PP over MCM-41 and Al-MCM-41. The pyrolysis over different heating rates (10K/min, 20K/min, 30K/min) was studied by Thermogravimetry Analysis (TGA) and kinetic parameters were obtained by Coats-Redfern method and isoconversion method. TG and DTG data shows that the two catalysts advance the pyrolysis reaction of PP significantly and reduce its peak temperature of DTG curve from 458°C to 341°C. The activation energy of pyrolysis of PP also has a remarkable reduction over the two catalysts. Py-GC/MS method was used to obtain the product distribution of pyrolysis of cellulose and PP separately and co-pyrolysis of cellulose and PP over MCM-41 and Al-MCM-41 at constant temperature of 650°C. Experiment results proved that co-pyrolysis with PP bring significant changes to the product distribution of cellulose. Oxygenated compounds such as furans are decreased, while yields of olefins and aromatics increase greatly. The yield of furans increases with the catalysis of MCM-41 as for the pyrolysis of cellulose and co-pyrolysis, while the yield of olefins and aromatics both experience significant growth over Al-MCM-41, which can be explained by the abundant acid centers in Al-MCM-41. Copyright © 2018 Elsevier B.V. All rights reserved.

MgO buffer layers on rolled nickel or copper as superconductor substrates

DOEpatents

Paranthaman, Mariappan; Goyal, Amit; Kroeger, Donald M.; List, III, Frederic A.

2001-01-01

Buffer layer architectures are epitaxially deposited on biaxially-textured rolled-Ni and/or Cu substrates for high current conductors, and more particularly buffer layer architectures such as MgO/Ag/Pt/Ni, MgO/Ag/Pd/Ni, MgO/Ag/Ni, MgO/Ag/Pd/Cu, MgO/Ag/Pt/Cu, and MgO/Ag/Cu. Techniques used to deposit these buffer layers include electron beam evaporation, thermal evaporation, rf magnetron sputtering, pulsed laser deposition, metal-organic chemical vapor deposition (MOCVD), combustion CVD, and spray pyrolysis.

Effects of Temperature and Steam Environment on Fatigue Behavior of Three SIC/SIC Ceramic Matrix Composites

DTIC Science & Technology

2008-09-01

Infiltration (CVI), Chemical Vapor Deposition (CVD) and polymer impregnation/ pyrolysis (PIP) [5:20, 32]. The SiC fibers currently... composite was infiltrated with a mixture of polymer , filler particles and solvent. During pyrolysis under nitrogen at temperatures > 1000 °C, the...using polymer infiltration and pyrolysis (PIP) method. Polymer infiltration and pyrolysis processing method allows near-net-shape molding and

Plasma impregnation of wood with fire retardants

NASA Astrophysics Data System (ADS)

Pabeliña, Karel G.; Lumban, Carmencita O.; Ramos, Henry J.

2012-02-01

The efficacy of chemical and plasma treatments with phosphate and boric compounds, and nitrogen as flame retardants on wood are compared in this study. The chemical treatment involved the conventional method of spraying the solution over the wood surface at atmospheric condition and chemical vapor deposition in a vacuum chamber. The plasma treatment utilized a dielectric barrier discharge ionizing and decomposing the flame retardants into innocuous simple compounds. Wood samples are immersed in either phosphoric acid, boric acid, hydrogen or nitrogen plasmas or a plasma admixture of two or three compounds at various concentrations and impregnated by the ionized chemical reactants. Chemical changes on the wood samples were analyzed by Fourier transform infrared spectroscopy (FTIR) while the thermal changes through thermo gravimetric analysis (TGA). Plasma-treated samples exhibit superior thermal stability and fire retardant properties in terms of highest onset temperature, temperature of maximum pyrolysis, highest residual char percentage and comparably low total percentage weight loss.

Photoconductivity in nanostructured sulfur-doped V2O5 thin films

NASA Astrophysics Data System (ADS)

Mousavi, M.; Yazdi, Sh. Tabatabai

2016-03-01

In this paper, S-doped vanadium oxide thin films with doping levels up to 40 at.% are prepared via spray pyrolysis method on glass substrates, and the effect of S-doping on the structural and photoconductivity related properties of β-V2O5 thin films is studied. The results show that most of the films have been grown in the tetragonal β-V2O5 phase structure with the preferred orientation along [200]. With increasing the doping level, the samples tend to be amorphous. The structure of the samples reveals to be nanobelt-shaped whose width decreases from nearly 100 nm to 40 nm with S concentration. The photoconductivity measurements show that by increasing the S-doping level, the photosensitivity increases, which is due to the prolonged electron’s lifetime as a result of enhanced defect states acting as trap levels.

Solid-solution Zn(O,S) thin films: Potential alternative buffer layer for Cu2ZnSnS4 solar cells

NASA Astrophysics Data System (ADS)

Jani, Margi; Raval, Dhyey; Chavda, Arvind; Mukhopadhyay, Indrajit; Ray, Abhijit

2018-05-01

This report investigates the alternative buffer material as Zn(O,S) for chalcogenide Cu2ZnSnS4 (CZTS) solar cell application. Using the band gap tailoring (band bowing) properties of Zn(O,S) system, performance of CZTS solar cell is explore in the present study. Reducing the band offsets with the hetero-junction partners plays a deterministic role in the performance of the device using Zn(O,S) as buffer layer. The experimental performance of the device with the CZTS/Zn(O,S) film developed by Spray pyrolysis method and analyze using J-V characterization in dark and illuminated configuration. Device with the best achievable performance shows Voc of 150 mV and Jsc of 0.47 mA/cm2 has been presented with the possibility of application in the energy harvesting.

Hierarchical TiO2/C micro-nano spheres as high-performance anode materials for sodium ion batteries

NASA Astrophysics Data System (ADS)

Ma, Xiao; Zhang, Zhihui; Tian, Jianliya; Xu, Beibei; Ping, Qiushi; Wang, Baofeng

The hierarchical TiO2/C microspheres were obtained via a facile method of in-situ hydrolysis and spray drying. Antase TiO2 nanoparticles were coherent to microspheres TiO2/C due to the pyrolysis of carbon source (PVP). Besides, the favorable electron transfer from carbon to TiO2 improves the electronic conductivity of TiO2 via the presence of Ti-C bond within TiO2/C composite. Charge-discharge tests show that TiO2/C microspheres delivered a good rate capability of 106.1mAhg‑1 at the high current density of 5Ag‑1 and an enhanced cyclic capacity. The superior electrochemical performance could be ascribed to the porous micro-nano structure, smaller crystal size and increased conductivity. The synthesis of TiO2/C microspheres is easy to scale up for satisfying high-performance sodium storage.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Apaydin, Ramazan Oguzhan; Ebin, Burcak; Gurmen, Sebahattin

Copper-Nickel (CuNi) nanostructured alloy particles were produced by Ultrasonic Spray Pyrolysis and Hydrogen Reduction Method (USP-HR) from high purity copper and nickel nitrate aqueous solutions. The effect of the precursor solution in the range of 0.1 and 0.5 mol/L on the morphology and crystallite size of CuNi nanoparticles were investigated under 2 h running time, 700 °C operating temperature and 0.5 L/min H{sub 2} flow rate. Particle size, morphology, composition and crystallite structure were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-Ray Diffraction (XRD). Particle characterization studies show that nanostructured alloy particles have cubic crystal structuremore » and they are in submicron size range with spherical morphology. The crystallite sizes of the particles calculated with Scherrer formula are 40 and 34 nm and average particles sizes observed from the SEM images are 300 and 510 nm for each experiment respectively.« less

'Beautiful' unconventional synthesis and processing technologies of superconductors and some other materials.

PubMed

Badica, Petre; Crisan, Adrian; Aldica, Gheorghe; Endo, Kazuhiro; Borodianska, Hanna; Togano, Kazumasa; Awaji, Satoshi; Watanabe, Kazuo; Sakka, Yoshio; Vasylkiv, Oleg

2011-02-01

Superconducting materials have contributed significantly to the development of modern materials science and engineering. Specific technological solutions for their synthesis and processing helped in understanding the principles and approaches to the design, fabrication and application of many other materials. In this review, we explore the bidirectional relationship between the general and particular synthesis concepts. The analysis is mostly based on our studies where some unconventional technologies were applied to different superconductors and some other materials. These technologies include spray-frozen freeze-drying, fast pyrolysis, field-assisted sintering (or spark plasma sintering), nanoblasting, processing in high magnetic fields, methods of control of supersaturation and migration during film growth, and mechanical treatments of composite wires. The analysis provides future research directions and some key elements to define the concept of 'beautiful' technology in materials science. It also reconfirms the key position and importance of superconductors in the development of new materials and unconventional synthesis approaches.

Au sensitized ZnO nanorods for enhanced liquefied petroleum gas sensing properties

NASA Astrophysics Data System (ADS)

Nakate, U. T.; Bulakhe, R. N.; Lokhande, C. D.; Kale, S. N.

2016-05-01

The zinc oxide (ZnO) nanorods have grown on glass substrate by spray pyrolysis deposition (SPD) method using zinc acetate solution. The phase formation, surface morphology and elemental composition of ZnO films have been investigated using X-ray diffraction, field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and energy dispersive X-ray (EDX) techniques. The liquefied petroleum gas (LPG) sensing response was remarkably improved by sensitization of gold (Au) surface noble metal on ZnO nanorods film. Maximum LPG response of 21% was observed for 1040 ppm of LPG, for pure ZnO nanorods sample. After Au sensitization on ZnO nanorods film sample, the LPG response greatly improved up to 48% at operating temperature 623 K. The improved LPG response is attributed Au sensitization with spill-over mechanism. Proposed model for LPG sensing mechanism discussed.

Electrical, optical and structural properties of FTO thin films fabricated by spray ultrasonic nebulizer technique from SnCl4 precursor

NASA Astrophysics Data System (ADS)

Lalasari, Latifa Hanum; Arini, Tri; Andriyah, Lia; Firdiyono, F.; Yuwono, Akhmad Herman

2018-05-01

Thin films of fluorine-doped tin oxide on glass were prepared by spray ultrasonic nebulizer technique from an economic anhydrous tin (IV) chloride (SnCl4) precursor. The effect of deposition time on the structural, electrical and optical properties of tin oxide thin films was investigated. This research a purpose to find an optimum deposition time during spray pyrolysis technique in order to produce FTO with the desired characteristics. For this purpose, soda lime glasses are heated at 350 °C on deposition time of 10, 15, 20 and 25 minutes. NH4F was doped at a ratio of 2 wt% in the SnCl4 precursor and methanol solvent. The results revealed that longer deposition times created decreased the electrical resistivity and optical transmittance of FTO layers. The highest optical transmittance was 84.808% and the lowest resistivity was 4.01×10-5 Ω.cm, obtained from FTO glass subjected to a 15-minute deposition time at deposition temperature of 350 °C. This is accordance to the TCO conductive glass requirements for the minimum resistivity value on scale 10-4 Ω.cm and optical transmittance value of 80-85%.

Quantitation of sugar content in pyrolysis liquids after acid hydrolysis using high-performance liquid chromatography without neutralization.

PubMed

Johnston, Patrick A; Brown, Robert C

2014-08-13

A rapid method for the quantitation of total sugars in pyrolysis liquids using high-performance liquid chromatography (HPLC) was developed. The method avoids the tedious and time-consuming sample preparation required by current analytical methods. It is possible to directly analyze hydrolyzed pyrolysis liquids, bypassing the neutralization step usually required in determination of total sugars. A comparison with traditional methods was used to determine the validity of the results. The calibration curve coefficient of determination on all standard compounds was >0.999 using a refractive index detector. The relative standard deviation for the new method was 1.13%. The spiked sugar recoveries on the pyrolysis liquid samples were between 104 and 105%. The research demonstrates that it is possible to obtain excellent accuracy and efficiency using HPLC to quantitate glucose after acid hydrolysis of polymeric and oligomeric sugars found in fast pyrolysis bio-oils without neutralization.

Pyrolysis characteristics of typical biomass thermoplastic composites

NASA Astrophysics Data System (ADS)

Cai, Hongzhen; Ba, Ziyu; Yang, Keyan; Zhang, Qingfa; Zhao, Kunpeng; Gu, Shiyan

The biomass thermoplastic composites were prepared by extrusion molding method with poplar flour, rice husk, cotton stalk and corn stalk. The thermo gravimetric analyzer (TGA) has also been used for evaluating the pyrolysis process of the composites. The results showed that the pyrolysis process mainly consists of two stages: biomass pyrolysis and the plastic pyrolysis. The increase of biomass content in the composite raised the first stage pyrolysis peak temperature. However, the carbon residue was reduced and the pyrolysis efficiency was better because of synergistic effect of biomass and plastic. The composite with different kinds of biomass have similar pyrolysis process, and the pyrolysis efficiency of the composite with corn stalk was best. The calcium carbonate could inhibit pyrolysis process and increase the first stage pyrolysis peak temperature and carbon residue as a filling material of the composite.

Catalytic pyrolysis-GC/MS of lignin from several sources

USDA-ARS?s Scientific Manuscript database

Lignin from four different sources extracted by various methods were pyrolyzed at 650 degree C using analytical pyrolysis methods, py-GC/MS. Pyrolysis was carried out in the absence and presence of two heterogeneous catalysts , an acidic zeolite (HZSM-5) catalyst and a mixed metal oxide catalyst (Co...

Method and apparatus for producing pyrolysis oil having improved stability

DOEpatents

Baird, Lance A.; Brandvold, Timothy A.; Muller, Stefan

2016-12-27

Methods and apparatus to improve hot gas filtration to reduce the liquid fuel loss caused by prolonged residence time at high temperatures are described. The improvement can be obtained by reducing the residence time at elevated temperature by reducing the temperature of the pyrolysis vapor, by reducing the volume of the pyrolysis vapor at the elevated temperature, by increasing the volumetric flow rate at constant volume of the pyrolysis vapor, or by doing a combination of these.

Effects of growth temperatures on the physical properties of Cu2ZnSnS4 thin films deposited through spray pyrolysis for solar cell applications

NASA Astrophysics Data System (ADS)

Fadavieslam, M. R.; Keshavarz, S.

2018-02-01

This paper reports the effects of substrate temperature on the structural, optical, and electrical properties of Cu2ZnSnS4 (CZTS) thin films deposited on soda lime glass through spray pyrolysis without sulfurization. Substrate temperatures ranged from 250 to 500 °C at a step of 50 °C, and a precursor solution was prepared by dissolving copper chloride, zinc acetate, zinc chloride, and thiourea in ethanol and di-ionized water. The films were characterized through X-ray diffraction (XRD), field emission scanning electron microscopy, ultraviolet-visible spectroscopy, and electrical resistance and Hall effect measurements, respectively, obtained by two-point probe and van der Pauw techniques. XRD revealed the formation of polycrystalline CZTS thin films and the appearance of relatively intense and sharp diffraction peaks at (112), (200), (220), and (312) of a kesterite phase with (112) preferential orientation, in which the crystalline degree increased as substrate temperature increased. Surface morphological analysis demonstrated the formation of a smooth, compact, and uniform CZTS surface. When substrate temperature increased from 250 to 500 °C, single-crystal grains increased from 6.38 to 28 nm, carrier concentration increased from 3.4 × 1017 to 2.36 × 1019 cm-3, Hall mobility increased from 30.96 to 68.52 cm2/V.S, optical band gap decreased from 1.74 to 1.14 eV, and resistivity decreased from 0.59 to 3.87 × 10-3 Ωcm. Hall effect analysis indicated that the films exhibited p-type conductivity.

Fullerene-like MoSe2 nanoparticles-embedded CNT balls with excellent structural stability for highly reversible sodium-ion storage.

PubMed

Choi, Seung Ho; Kang, Yun Chan

2016-02-21

Three-dimensional (3D) porous-structured carbon nanotube (CNT) balls embedded with fullerene-like MoSe2 nanocrystals were successfully prepared by the spray pyrolysis process and subsequent selenization process. The MoO2-CNT composite balls prepared by spray pyrolysis transformed into the fullerene-like MoSe2/CNT (F-MoSe2/CNT) composite balls by the selenization process. The F-MoSe2/CNT composite balls exhibited superior sodium-ion storage properties to bare MoSe2 and MoSe2/CNT with a filled structure (N-MoSe2/CNT), both of which were prepared as comparison samples. The 250(th) discharge capacities of bare MoSe2, N-MoSe2/CNT composite balls, and F-MoSe2/CNT composite balls were 144, 200, and 296 mA h g(-1), respectively, at a high current density of 1.0 A g(-1), and their capacity retentions measured from the second cycle were 37%, 66%, and 83%, respectively. The 10(th) discharge capacities of the F-MoSe2/CNT composite balls were 382, 346, 310, 280, and 255 mA h g(-1) at current densities of 0.2, 0.5, 1.5, 3.0, and 5.0 A g(-1), respectively. The synergetic effect of the fullerene-like MoSe2 nanocrystals with ultrafine sizes and the CNT balls with a tangled and 3D porous structure and high electrical conductivity resulted in excellent sodium-ion storage properties of the F-MoSe2/CNT composite balls.

High-capacity cathodes for lithium-ion batteries from nanostructured LiFePO4 synthesized by highly-flexible and scalable flame spray pyrolysis

NASA Astrophysics Data System (ADS)

Hamid, N. A.; Wennig, S.; Hardt, S.; Heinzel, A.; Schulz, C.; Wiggers, H.

2012-10-01

Olivine, LiFePO4 is a promising cathode material for lithium-ion batteries due to its low cost, environmental acceptability and high stability. Its low electric conductivity prevented it for a long time from being used in large-scale applications. Decreasing its particle size along with carbon coating significantly improves electronic conductivity and lithium diffusion. With respect to the controlled formation of very small particles with large specific surface, gas-phase synthesis opens an economic and flexible route towards high-quality battery materials. Amorphous FePO4 was synthesized as precursor material for LiFePO4 by flame spray pyrolysis of a solution of iron acetylacetonate and tributyl phosphate in toluene. The pristine FePO4 with a specific surface from 126-218 m2 g-1 was post-processed to LiFePO4/C composite material via a solid-state reaction using Li2CO3 and glucose. The final olivine LiFePO4/C particles still showed a large specific surface of 24 m2 g-1 and were characterized using X-ray diffraction (XRD), electron microscopy, X-ray photoelectron spectrocopy (XPS) and elemental analysis. Electrochemical investigations of the final LiFePO4/C composites show reversible capacities of more than 145 mAh g-1 (about 115 mAh g-1 with respect to the total coating mass). The material supports high drain rates at 16 C while delivering 40 mAh g-1 and causes excellent cycle stability.

Thermal annealing dynamics of carbon-coated LiFePO{sub 4} nanoparticles studied by in-situ analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krumeich, Frank, E-mail: krumeich@inorg.chem.ethz.ch; Waser, Oliver; Pratsinis, Sotiris E.

The thermal behavior of core-shell carbon-coated lithium iron phosphate (LiFePO{sub 4}-C) nanoparticles made by flame spray pyrolysis (FSP) during annealing was investigated by in-situ transmission electron microscopy (TEM), in-situ X-ray powder diffraction (XRD) as well as ex-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Crystallization of the initially glassy LiFePO{sub 4}-C nanoparticles starts at quite low temperatures (T=400 °C), forming single crystals inside the confinement of the carbon shell. Upon increasing the temperature to T≥700 °C, LiFePO{sub 4} starts to diffuse through the carbon shell resulting in cavities inside the mostly intact carbon shell. By increasing the temperature further tomore » T≥800 °C, the initial core-shell morphology converts into open carbon shells (flakes and cenospheres) and bulky LiFePO{sub 4} particles (diameter in the range 300–400 nm), in agreement with ex-situ experiments. - Graphical abstract: TEM images of a typical sample area recorded at room temperature and after heating in-situ heating reveal the growth of particles and the formation of empty carbon cages. - Highlights: • LiFePO{sub 4} coated by a carbon shell is produced by flame spray pyrolysis. • The amorphous LiFePO{sub 4} starts to crystallize at 400 °C as revealed by in-situ XRD. • Crystal growth was visualized by TEM heating experiments. • The formation of empty carbon cages starts at 700 °C.« less

The electrical, optical, structural and thermoelectrical characterization of n- and p-type cobalt-doped SnO 2 transparent semiconducting films prepared by spray pyrolysis technique

NASA Astrophysics Data System (ADS)

Bagheri-Mohagheghi, Mohammad-Mehdi; Shokooh-Saremi, Mehrdad

2010-10-01

The electrical, optical and structural properties of Cobalt (Co) doped SnO 2 transparent semiconducting thin films, deposited by the spray pyrolysis technique, have been studied. The SnO 2:Co films, with different Co-content, were deposited on glass substrates using an aqueous-ethanol solution consisting of tin and cobalt chlorides. X-ray diffraction studies showed that the SnO 2:Co films were polycrystalline only with tin oxide phases and preferential orientations along (1 1 0) and (2 1 1) planes and grain sizes in the range 19-82 nm. Optical transmittance spectra of the films showed high transparency ∼75-90% in the visible region, decreasing with increase in Co-doping. The optical absorption edge for undoped SnO 2 films was found to be 3.76 eV, while for higher Co-doped films shifted toward higher energies (shorter wavelengths) in the range 3.76-4.04 eV and then slowly decreased again to 4.03 eV. A change in sign of the Hall voltage and Seebeck coefficient was observed for a specific acceptor dopant level ∼11.4 at% in film and interpreted as a conversion from n-type to p-type conductivity. The thermoelectric electro-motive force (e.m.f.) of the films was measured in the temperature range 300-500 K and Seebeck coefficients were found in the range from -62 to +499 μVK -1 for various Co-doped SnO 2 films.

Aerosol-assisted molten salt synthesis of NaInS(2) nanoplates for use as a new photoanode material.

PubMed

Mann, Amanda K P; Wicker, Susanne; Skrabalak, Sara E

2012-12-04

NaInS(2) , a H(2) -evolving photocatalyst, is synthesized as single-crystalline hexagonal plates by coupling a molten salt synthesis with ultrasonic spray pyrolysis (USP) for the first time. USP NaInS(2) films are used as a new photoanode material and have an initial photocurrent of ≈37 μA/cm(2) upon illumination and activities 25 times greater than films made from a standard non-aerosol NaInS(2) sample. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of film thickness on NO2 gas sensing properties of sprayed orthorhombic nanocrystalline V2O5 thin films

NASA Astrophysics Data System (ADS)

Mane, A. A.; Moholkar, A. V.

2017-09-01

The nanocrystalline V2O5 thin films with different thicknesses have been grown onto the glass substrates using chemical spray pyrolysis (CSP) deposition method. The XRD study shows that the films exhibit an orthorhombic crystal structure. The narrow scan X-ray photoelectron spectrum of V-2p core level doublet gives the binding energy difference of 7.3 eV, indicating that the V5+ oxidation state of vanadium. The FE-SEM micrographs show the formation of nanorods-like morphology. The AFM micrographs show the high surface area to volume ratio of nanocrystalline V2O5 thin films. The optical study gives the band gap energy values of 2.41 eV, 2.44 eV, 2.47 eV and 2.38 eV for V2O5 thin films deposited with the thicknesses of 423 nm, 559 nm, 694 nm and 730 nm, respectively. The V2O5 film of thickness 559 nm shows the NO2 gas response of 41% for 100 ppm concentration at operating temperature of 200 °C with response and recovery times of 20 s and 150 s, respectively. Further, it shows the rapid response and reproducibility towards 10 ppm NO2 gas concentration at 200 °C. Finally, NO2 gas sensing mechanism based on chemisorption process is discussed.

Degradation of organic dyes using spray deposited nanocrystalline stratified WO3/TiO2 photoelectrodes under sunlight illumination

NASA Astrophysics Data System (ADS)

Hunge, Y. M.; Yadav, A. A.; Mahadik, M. A.; Bulakhe, R. N.; Shim, J. J.; Mathe, V. L.; Bhosale, C. H.

2018-02-01

The need to utilize TiO2 based metal oxide hetero nanostructures for the degradation of environmental pollutants like Rhodamine B and reactive red 152 from the wastewater using stratified WO3/TiO2 catalyst under sunlight illumination. WO3, TiO2 and stratified WO3/TiO2 catalysts were prepared by a spray pyrolysis method. It was found that the stratified WO3/TiO2 heterostructure has high crystallinity, no mixed phase formation occurs, strong optical absorption in the visible region of the solar spectrum, and large surface area. The photocatalytic activity was tested for degradation of Rhodamine B (Rh B) and reactive red 152 in an aqueous medium. TiO2 layer in stratified WO3/TiO2 catalyst helps to extend its absorption spectrum in the solar light region. Rh B and Reactive red 152is eliminated up to 98 and 94% within the 30 and 40 min respectively at optimum experimental condition by stratified WO3/TiO2. Moreover, stratified WO3/TiO2 photoelectrode has good stability and reusability than individual TiO2 and WO3 thin film in the degradation of Rh B and reactive red 152. The photoelectrocatalytic experimental results indicate that stratified WO3/TiO2 photoelectrode is a promising material for dye removal.

Simplifying pyrolysis; using gasification to produce corn stover and wheat straw biochar for sorptive and horitcultural media

USDA-ARS?s Scientific Manuscript database

Biochar is a renewable, useful material that can be utilized in many different applications. Biochar is commonly produced via pyrolysis methods using a retort-style oven with inert gas. Gasification is another method that can utilize pyrolysis to produce biochar, but with the advantage of not requir...

Pyrolysis and dehalogenation of plastics from waste electrical and electronic equipment (WEEE): a review.

PubMed

Yang, Xiaoning; Sun, Lushi; Xiang, Jun; Hu, Song; Su, Sheng

2013-02-01

Plastics from waste electrical and electronic equipment (WEEE) have been an important environmental problem because these plastics commonly contain toxic halogenated flame retardants which may cause serious environmental pollution, especially the formation of carcinogenic substances polybrominated dibenzo dioxins/furans (PBDD/Fs), during treat process of these plastics. Pyrolysis has been proposed as a viable processing route for recycling the organic compounds in WEEE plastics into fuels and chemical feedstock. However, dehalogenation procedures are also necessary during treat process, because the oils collected in single pyrolysis process may contain numerous halogenated organic compounds, which would detrimentally impact the reuse of these pyrolysis oils. Currently, dehalogenation has become a significant topic in recycling of WEEE plastics by pyrolysis. In order to fulfill the better resource utilization of the WEEE plastics, the compositions, characteristics and dehalogenation methods during the pyrolysis recycling process of WEEE plastics were reviewed in this paper. Dehalogenation and the decomposition or pyrolysis of WEEE plastics can be carried out simultaneously or successively. It could be 'dehalogenating prior to pyrolysing plastics', 'performing dehalogenation and pyrolysis at the same time' or 'pyrolysing plastics first then upgrading pyrolysis oils'. The first strategy essentially is the two-stage pyrolysis with the release of halogen hydrides at low pyrolysis temperature region which is separate from the decomposition of polymer matrixes, thus obtaining halogenated free oil products. The second strategy is the most common method. Zeolite or other type of catalyst can be used in the pyrolysis process for removing organohalogens. The third strategy separate pyrolysis and dehalogenation of WEEE plastics, which can, to some degree, avoid the problem of oil value decline due to the use of catalyst, but obviously, this strategy may increase the cost of whole recycling process. Copyright © 2012 Elsevier Ltd. All rights reserved.

Catalytic and non-catalytic pyrolysis of biomass in non-inert environments for production of deoxygenated bio-oil and chemicals

USDA-ARS?s Scientific Manuscript database

Fast pyrolysis processes are among the most effective methods for liquefaction of lignocellulosic biomass. Catalytic fast pyrolysis (CFP) over HZSM-5 or other zeolites and/or utilization of reactive atmospheres such as in the non-catalytic Tail Gas Reactive Pyrolysis (TRGP) process, a recent patent...

Deposition and characterization of spray pyrolysed p-type Cu2SnS3 thin film for potential absorber layer of solar cell

NASA Astrophysics Data System (ADS)

Thiruvenkadam, S.; Sakthi, P.; Prabhakaran, S.; Chakravarty, Sujay; Ganesan, V.; Rajesh, A. Leo

2018-06-01

Thin film of ternary Cu2SnS3 (CTS), a potential absorber layer for solar cells was successfully deposited by chemical spray pyrolysis technique. The GIXRD pattern revealed that the film having tetragonal Cu2SnS3 phase with the preferential orientation along (112), (200), (220) and (312) plane and it is further confirmed using Raman spectroscopy by the existence of Raman peak at 320 cm-1. Atomic Force Microscopy (AFM) was used to estimate the surface roughness of 28.8 nm. The absorption coefficient was found to be greater than the order of 105 cm-1 and bandgap of 1.70 eV. Hall effect measurement indicates the p type nature of the film with a hole concentration of 1.03 × 1016cm-3 and a hall mobility of 404 cm2/V. The properties of CTS thin film confirmed suitable to be a potential absorber layer material for photovoltaic applications.

Fabrication of tri metal oxides gas detector for lung inflammation

NASA Astrophysics Data System (ADS)

Othman, Farhad M.; Abdul-Hamead, Alaa A.; Aljanabi, Zena A.

2018-05-01

This paper describes the use of semiconductor gas sensor for detection of Carbon monoxide levels in exhaled human breath serving as breath marker of lung inflammation. In this research tri metal oxides were fabricated by simple chemical spray pyrolysis technique from mixtures of tow composition (Na2WO4: SnCl2 and Na2WO4, : 3 SnCl2) salts at concentration (0.1M), were fabricated on silicon substrate n-type (100) with thickness was about (625 µm) using water soluble as precursors at a substrate temperature (350 °C ±5), with spray distance (25 cm) and their gas sensing properties toward Carbon monoxide gas at concentration (10) ppm in air were investigated at room temperature, furthermore structural and morphology properties were inspecting. Experimental results show that the WSnO4 and SnO2 thin films were achieved from the used salts with thickness about (0.2 ± 0.05 nm), which make the sensor suitable for the detection of carbon monoxide levels in in exhaled human breath.

Spray deposited MnFe2O4 thin films for detection of ethanol and acetone vapors

NASA Astrophysics Data System (ADS)

Nagarajan, V.; Thayumanavan, A.

2018-01-01

Spinel MnFe2O4 films were synthesized with the help of spray pyrolysis technique. The morphology study shows fine crushed sand grain morphology of the film. The structural investigation verifies the polycrystalline nature of prepared MnFe2O4 films, which possess the spinel structure. Crystalline size is found to be around 23.5 nm-37.4 nm morphology analyses. Energy dispersive spectroscopy validates the presence of oxygen, iron and manganese in MnFe2O4 film. The prepared MnFe2O4 film is extremely sensitive towards ethanol molecules at 300 K. The electrical resistance of MnFe2O4 thin film decreases quickly when ethanol and acetone vapor molecules are adsorbed on base material. The synthesized MnFe2O4 film is also highly sensitive towards acetone molecules at ambient temperature. The selectivity, sensing response, stability and recovery time of MnFe2O4 film towards acetone and ethanol detection are analyzed in the present work.

Low-temperature spray-deposited indium oxide for flexible thin-film transistors and integrated circuits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petti, Luisa; Faber, Hendrik; Anthopoulos, Thomas D., E-mail: t.anthopoulos@imperial.ac.uk

2015-03-02

Indium oxide (In{sub 2}O{sub 3}) films were deposited by ultrasonic spray pyrolysis in ambient air and incorporated into bottom-gate coplanar and staggered thin-film transistors. As-fabricated devices exhibited electron-transporting characteristics with mobility values of 1 cm{sup 2}V{sup −1}s{sup −1} and 16 cm{sup 2}V{sup −1}s{sup −1} for coplanar and staggered architectures, respectively. Integration of In{sub 2}O{sub 3} transistors enabled realization of unipolar inverters with high gain (5.3 V/V) and low-voltage operation. The low temperature deposition (≤250 °C) of In{sub 2}O{sub 3} also allowed transistor fabrication on free-standing 50 μm-thick polyimide foils. The resulting flexible In{sub 2}O{sub 3} transistors exhibit good characteristics and remain fully functional even whenmore » bent to tensile radii of 4 mm.« less

Effect of solvent volume on the physical properties of aluminium doped nanocrystalline zinc oxide thin films deposited using a simplified spray pyrolysis technique

NASA Astrophysics Data System (ADS)

Jabena Begum, N.; Mohan, R.; Ravichandran, K.

2013-01-01

Aluminium doped zinc oxide (AZO) thin films were deposited by employing a low cost and simplified spray technique using a perfume atomizer from starting solutions having different volumes (10, 20, … , 50 mL) of solvent. The effect of solvent volume on the structural, electrical, optical, photoluminescence (PL) and surface morphological properties was studied. The electrical resistivity of the AZO films is remarkably influenced by the variation in the solvent volume. The X-ray diffraction profiles clearly showed that all the films have preferential orientation along the (0 0 2) plane irrespective of the solvent volume. The crystallite size was found to be in the nano range of 35-46 nm. The optical transmittance in the visible region is desirably high (>85%). The AFM images show columnar morphology with varying grain size. The PL studies revealed that the AZO film deposited from 50 mL of solvent volume has good quality with lesser defect density.

Investigations on the structural, morphological, optical and electrical properties of undoped and nanosized Zn-doped CdS thin films prepared by a simplified spray technique

NASA Astrophysics Data System (ADS)

Anbarasi, M.; Nagarethinam, V. S.; Balu, A. R.

2014-12-01

CdS and Zn-doped CdS (CdS:Zn) thin films have been deposited on glass substrates by spray pyrolysis technique using a perfume atomizer. The influence of Zn incorporation on the structural, morphological, optical and electrical properties of the films has been studied. All the films exhibit hexagonal phase with (0 0 2) as preferential orientation. A shift of the (0 0 2) diffraction peak towards higher diffraction angle is observed with increased Zn doping. The optical studies confirmed that the transparency increases as Zn doping level increases and the film coated with 2 at.% Zn doping has the maximum transmittance of about 90 %. The sheet resistance (R sh ) decreases as the Zn-doping level increases and a minimum value of 1.113 × 103 Ω/sq is obtained for the film coated with 8 at.% Zn dopant. The CdS film coated with 8 at.% Zn dopant has the best structural, morphological and electrical properties.

Thermal behavior of vehicle plastic blends contained acrylonitrile-butadiene-styrene (ABS) in pyrolysis using TG-FTIR.

PubMed

Liu, Guicai; Liao, Yanfen; Ma, Xiaoqian

2017-03-01

As important plastic blends in End-of-Life vehicles (ELV), pyrolysis profiles of ABS/PVC, ABS/PA6 and ABS/PC were investigated using thermogravimetric-Fourier transform infrared spectrometer (TG-FTIR). Also, CaCO 3 was added as plastic filler to discuss its effects on the pyrolysis of these plastics. The results showed that the interaction between ABS and PVC made PVC pyrolysis earlier and HCl emission slightly accelerated. The mixing of ABS and PA6 made their decomposition temperature closer, and ketones in PA6 pyrolysis products were reduced. The presence of ABS made PC pyrolysis earlier, and phenyl compounds in PC pyrolysis products could be transferred into alcohol or H 2 O. The interaction between ABS and other polymers in pyrolysis could be attributed to the intermolecular radical transfer, and free radicals from the polymer firstly decomposed led to a fast initiation the decomposition of the other polymer. As plastic filler, CaCO 3 promoted the thermal decomposition of PA6 and PC, and had no obvious effects on ABS and PVC pyrolysis process. Also, CaCO 3 made the pyrolysis products from PA6 and PC further decomposed into small-molecule compounds like CO 2 . The kinetics analysis showed that isoconversional method like Starink method was more suitable for these polymer blends. Starink method showed the average activation energy of ABS50/PVC50, ABS50/PA50 and ABS50/PC50 was 186.63kJ/mol, 239.61kJ/mol and 248.95kJ/mol, respectively, and the interaction among them could be reflected by the activation energy variation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Study on the NO removal efficiency of the lignite pyrolysis coke catalyst by selective catalytic oxidation method

PubMed Central

Wen, Xin; Ma, Zhenhua; Zhang, Lei; Sha, Xiangling; He, Huibin; Zeng, Tianyou; Wang, Yusu; Chen, Jihao

2017-01-01

Selective catalytic oxidation (SCO) method is commonly used in wet denitration technology; NO after the catalytic oxidation can be removed with SO2 together by wet method. Among the SCO denitration catalysts, pyrolysis coke is favored by the advantages of low cost and high catalytic activity. In this paper, SCO method combined with pyrolysis coke catalyst was used to remove NO from flue gas. The effects of different SCO operating conditions and different pyrolysis coke catalyst made under different process conditions were studied. Besides, the specific surface area of the catalyst and functional groups were analyzed with surface area analyzer and Beohm titration. The results are: (1) The optimum operating conditions of SCO is as follows: the reaction temperature is 150°C and the oxygen content is 6%. (2) The optimum pyrolysis coke catalyst preparation processes are as follows: the pyrolysis final temperature is 750°C, and the heating rate is 44°C / min. (3) The characterization analysis can be obtained: In the denitration reaction, the basic functional groups and the phenolic hydroxyl groups of the catalyst play a major role while the specific surface area not. PMID:28793346

Studies on thermal decomposition behaviors of polypropylene using molecular dynamics simulation

NASA Astrophysics Data System (ADS)

Huang, Jinbao; He, Chao; Tong, Hong; Pan, Guiying

2017-11-01

Polypropylene (PP) is one of the main components of waste plastics. In order to understand the mechanism of PP thermal decomposition, the pyrolysis behaviour of PP has been simulated from 300 to 1000 K in periodic boundary conditions by molecular dynamic method, based on AMBER force field. The simulation results show that the pyrolysis process of PP can mostly be divided into three stages: low temperature pyrolysis stage, intermediate temperature stage and high temperature pyrolysis stage. PP pyrolysis is typical of random main-chain scission, and the possible formation mechanism of major pyrolysis products was analyzed.

Acidity of biomass fast pyrolysis bio-oils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oasmaa, Anja; Elliott, Douglas C.; Korhonen, Jaana

2010-12-17

The use of the TAN method for measuring the acidity of biomass fast pyrolysis bio-oil was evaluated. Suggestions for carrying out the analysis have been made. The TAN method by ASTM D664 or D3339 can be used for measuring the acidity of fast pyrolysis bio-oils and their hydrotreating products. The main difference between the methods is that ASTM D664 is specified for higher TAN values than ASTM D3339. Special focus should be placed on the interpretation of the TAN curves because they differ significantly from those of mineral oils. The curve for bio-oils is so gentle that the automatic detectionmore » may not observe the end point properly and derivatization should be used. The acidity of fast pyrolysis bio-oils is mainly derived (60-70%) from volatile acids. Other groups of compounds in fast pyrolysis bio-oils that influence acidity include phenolics, fatty and resin acids, and hydroxy acids.« less

Methods and apparatuses for deoxygenating biomass-derived pyrolysis oil

DOEpatents

Baird, Lance Awender; Brandvold, Timothy A.

2015-10-20

Embodiments of methods and apparatuses for deoxygenating a biomass-derived pyrolysis oil are provided. In one example, a method comprises the steps of separating a low-oxygen biomass-derived pyrolysis oil effluent into a low-oxygen-pyoil organic phase stream and an aqueous phase stream. Phenolic compounds are removed from the aqueous phase stream to form a phenolic-rich diluent recycle stream. A biomass-derived pyrolysis oil stream is diluted and heated with the phenolic-rich diluent recycle stream to form a heated diluted pyoil feed stream. The heated diluted pyoil feed stream is contacted with a deoxygenating catalyst in the presence of hydrogen to deoxygenate the heated diluted pyoil feed stream.

Kinetics evaluation and thermal decomposition characteristics of co-pyrolysis of municipal sewage sludge and hazelnut shell.

PubMed

Zhao, Bing; Xu, Xinyang; Li, Haibo; Chen, Xi; Zeng, Fanqiang

2018-01-01

Hazelnut shell, as novel biomass, has lower ash content and abundant hydrocarbon, which can be utilized resourcefully with municipal sewage sludge (MSS) by co-pyrolyisis to decrease total content of pollution. The co-pyrolysis of MSS and hazelnut shell blend was analyzed by a method of multi-heating rates and different blend ratios with TG-DTG-MS under N 2 atmosphere. The apparent activation energy of co-pyrolysis was calculated by three iso-conversional methods. Satava-Sestak method was used to determine mechanism function G(α) of co-pyrolysis, and Lorentzian function was used to simulate multi-peaks curves. The results showed there were four thermal decomposition stages, and the biomass were cracked and evolved at different temperature ranges. The apparent activation energy increased from 123.99 to 608.15kJ/mol. The reaction mechanism of co-pyrolysis is random nucleation and nuclei growth. The apparent activation energy and mechanism function afford a theoretical groundwork for co-pyrolysis technology. Copyright © 2017 Elsevier Ltd. All rights reserved.

Post-annealing effect on optical absorbance of hydrothermally grown zinc oxide nanorods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohar, Rahmat Setiawan; Djuhana, Dede; Imawan, Cuk

In this study, the optical absorbance of zinc oxide (ZnO) nanorods was investigated. The ZnO thin film were deposited on indium tin oxide (ITO) layers using ultrasonic spray pyrolysis (USP) method and then grown by hydrothermal method. In order to improve the optical absorbance, the ZnO nanorods were then post-annealed for one hour at three different of temperatures, namely 250, 400, and 500 °C. The X-ray diffraction (XRD) spectra and FESEM images show that the ZnO nanorods have the hexagonal wurtzite crystal structure and the increasing of post-annealing temperature resulted in the increasing of crystallite size from 38.2 nm to 48.4 nm.more » The UV-vis spectra shows that all samples of ZnO nanorods exhibited the identical sharp absorption edge at 390 nm indicating that all samples have the same bandgap. The post-annealing process seemed to decrease the optical absorbance in the region of 300-550 nm and increase the optical absorbance in the region of 550-700 nm..« less

Zr-doped SnO2 thin films synthesized by spray pyrolysis technique for barrier layers in solar cells

NASA Astrophysics Data System (ADS)

Reddy, N. Nanda Kumar; Akkera, Harish Sharma; Sekhar, M. Chandra; Park, Si-Hyun

2017-12-01

In the present work, we investigated the effect of Zr doping (0-6 at%) on the structural, electrical, and optical properties of tin oxide (SnO2) thin films deposited onto glass substrates using a spray pyrolysis technique. The room-temperature X-ray diffraction pattern shows that all deposited films exhibit polycrystalline tetragonal structure. The pure SnO2 film is grown along a preferred (200) direction, whereas Zr-doped SnO2 (Zr:SnO2) films started growing along the (220) orientation along with a high intensity peak of (200). Scanning electron microscope (SEM) and atomic force microscope (AFM) images showed that the grains of the films are spherical in structure, and the grain size decreased with increasing of Zr concentration. The optical transmission spectra of deposited films as a function of wavelength confirm that the average optical transmittance is > 85% for Zr:SnO2 films. The value of the optical bandgap is significantly decreased from 3.94 to 3.68 eV with increasing Zr concentration. Furthermore, the electrical measurements found that the sheet resistance ( R sh) and resistivity ( ρ) values are decreased with increasing of Zr doping. The lowest values of R sh = 6.82 Ω and ρ = 0.4 × 10- 3 Ω cm are found in 6-at% Zr-doped SnO2 film. In addition, a good efficiency value of the figure of merit ( ɸ = 3.35 × 10- 3 Ω-1) is observed in 6-at% Zr-doped SnO2 film. These outstanding properties of Zr-doped SnO2 films make them useful for several optoelectronic device applications.

Effect of Zn/Sn molar ratio on the microstructural and optical properties of Cu2Zn1-xSnxS4 thin films prepared by spray pyrolysis technique

NASA Astrophysics Data System (ADS)

Thiruvenkadam, S.; Prabhakaran, S.; Sujay Chakravarty; Ganesan, V.; Vasant Sathe; Santhosh Kumar, M. C.; Leo Rajesh, A.

2018-03-01

Quaternary kesterite Cu2ZnSnS4 (CZTS) compound is one of the most promising semiconductor materials consisting of abundant and eco-friendly elements for absorption layer in thin film solar cells. The effect of Zn/Sn ratio on Cu2Zn1-xSnxS4 (0 ≤ x ≤ 1) thin films were studied by deposited by varying molar volumes in the precursor solution of zinc and tin was carried out in proportion of (1-x) and x respectively onto soda lime glass substrates kept at 573 K by using chemical spray pyrolysis technique. The GIXRD pattern revealed that the films having composites of Cu2ZnSnS4, Cu2SnS3, Sn2S3, CuS and ZnS phases. The crystallinity and grain size were found to increase by increasing the x value and the preferential orientation along (103), (112), (108) and (111) direction corresponding to CZTS, Cu2SnS3, CuS, and ZnS phases respectively. Micro-Raman spectra exposed a prominent peak at 332 cm-1 corresponding to the CZTS phase. Atomic force microscopy was employed to study the grain size and roughness of the deposited thin films. The optical band gap was found to lie between 1.45 and 2.25 eV and average optical absorption coefficient was found to be greater than 105 cm-1. Hall measurements exhibited that all the deposited Cu2Zn1-xSnxS4 films were p type and the resistivity lies between 10.9 ×10-2Ωcm and 149.6 × 10-2Ωcm .

Improvement of Transparent Conducting Performance on Oxygen-Activated Fluorine-Doped Tin Oxide Electrodes Formed by Horizontal Ultrasonic Spray Pyrolysis Deposition.

PubMed

Koo, Bon-Ryul; Oh, Dong-Hyeun; Riu, Doh-Hyung; Ahn, Hyo-Jin

2017-12-27

In this study, highly transparent conducting fluorine-doped tin oxide (FTO) electrodes were fabricated using the horizontal ultrasonic spray pyrolysis deposition. In order to improve their transparent conducting performances, we carried out oxygen activation by adjusting the ratio of O 2 /(O 2 +N 2 ) in the carrier gas (0%, 20%, and 50%) used during the deposition process. The oxygen activation on the FTO electrodes accelerated the substitution concentration of F (F O • ) into the oxygen sites in the FTO electrode while the oxygen vacancy (V O • • ) concentration was reduced. In addition, due to growth of pyramid-shaped crystallites with (200) preferred orientations, this oxygen activation caused the formation of a uniform surface structure. As a result, compared to others, the FTO electrode prepared at 50% O 2 showed excellent electrical and optical properties (sheet resistance of ∼4.0 ± 0.14 Ω/□, optical transmittance of ∼85.3%, and figure of merit of ∼5.09 ± 0.19 × 10 -2 Ω -1 ). This led to a superb photoconversion efficiency (∼7.03 ± 0.20%) as a result of the improved short-circuit current density. The photovoltaic performance improvement can be defined by the decreased sheet resistance of FTO used as a transparent conducting electrode in dye-sensitized solar cells (DSSCs), which is due to the combined effect of the high carrier concentration by the improved F O • concentration on the FTO electrodes and the fasted Hall mobility by the formation of a uniform FTO surface structure and distortion relaxation on the FTO lattices resulting from the reduced V O • • • concentration.

Structural, electrical and optical properties of Al-Sn codoped ZnO transparent conducting layer deposited by spray pyrolysis technique

NASA Astrophysics Data System (ADS)

Bedia, A.; Bedia, F. Z.; Aillerie, M.; Maloufi, N.

2017-11-01

Low cost Al-Sn codoped ZnO (ATZO) Transparent Conductive Oxide films were deposited by spray pyrolysis on glass substrate. The influence of Al-Sn codoping on the structural, optical and electrical properties of ZnO thin films was studied by comparing the same properties obtained in undoped ZnO, Al doped ZnO (AZO) and Sn doped ZnO (TZO) thin films. The so-obtained films crystallized in hexagonal wurtzite structure. The morphology and structural defects have been investigated by both High resolution Field Effect Scanning Electron Microscopy (FE-SEM) and Raman spectroscopy at 532 nm excitation source. In the visible region, the undoped and doped films show an average transmittance of the order of 85%, while for ATZO thin film, it is of the order of 72%, which points out a degradation of the optical properties due to the co-doping. The optical band gap of ATZO thin film achieves 3.31eV and this shift, compared to the referred samples is attributed to the Burstein-Moss (BM) and band gap narrowing (BGN) opposite effects which is due to the increase of the carrier concentration in degenerate semiconductors. Within all the samples, the ATZO thin film exhibits the lowest electrical resistivity of 4.56 × 10-3 Ωcm with a Hall mobility equal to 2.13 cm2 V-1s-1, and the highest carrier concentration of 6.41 × 1020 cm-3. The performance of ATZO transparent conductive oxide film are determined by its figure of merit (φTC), found equal to 1.69 10-4 Ω-1, which is a suitable value for potentially high-performance solar cell applications.

Rapid habitability assessment of Mars samples by pyrolysis-FTIR

NASA Astrophysics Data System (ADS)

Gordon, Peter R.; Sephton, Mark A.

2016-02-01

Pyrolysis Fourier transform infrared spectroscopy (pyrolysis FTIR) is a potential sample selection method for Mars Sample Return missions. FTIR spectroscopy can be performed on solid and liquid samples but also on gases following preliminary thermal extraction, pyrolysis or gasification steps. The detection of hydrocarbon and non-hydrocarbon gases can reveal information on sample mineralogy and past habitability of the environment in which the sample was created. The absorption of IR radiation at specific wavenumbers by organic functional groups can indicate the presence and type of any organic matter present. Here we assess the utility of pyrolysis-FTIR to release water, carbon dioxide, sulfur dioxide and organic matter from Mars relevant materials to enable a rapid habitability assessment of target rocks for sample return. For our assessment a range of minerals were analyzed by attenuated total reflectance FTIR. Subsequently, the mineral samples were subjected to single step pyrolysis and multi step pyrolysis and the products characterised by gas phase FTIR. Data from both single step and multi step pyrolysis-FTIR provide the ability to identify minerals that reflect habitable environments through their water and carbon dioxide responses. Multi step pyrolysis-FTIR can be used to gain more detailed information on the sources of the liberated water and carbon dioxide owing to the characteristic decomposition temperatures of different mineral phases. Habitation can be suggested when pyrolysis-FTIR indicates the presence of organic matter within the sample. Pyrolysis-FTIR, therefore, represents an effective method to assess whether Mars Sample Return target rocks represent habitable conditions and potential records of habitation and can play an important role in sample triage operations.

Novel Precursor Approached for CMC Derived by Polymer Pyrolysis

DTIC Science & Technology

1994-02-15

to remove signals from probe polymer materials. C. Pyrolysis Methods The conversion of polymeric PMVS to SiC -containing ceramic was studied by... Composite Fabrication Methods Ceramic matrix composites with different matrix compositions were fabricated using the Polymer Impregnation- Pyrolysis (PIP...Pyrolyzed composites were re- infiltrated with the appropriate polymer matrix source under vacuum, and cured in an autoclave under 100 psi overpressure of N2

A Comprehensive Study on Pyrolysis Mechanism of Substituted β-O-4 Type Lignin Dimers.

PubMed

Jiang, Xiaoyan; Lu, Qiang; Hu, Bin; Liu, Ji; Dong, Changqing; Yang, Yongping

2017-11-09

In order to understand the pyrolysis mechanism of β- O -4 type lignin dimers, a pyrolysis model is proposed which considers the effects of functional groups (hydroxyl, hydroxymethyl and methoxyl) on the alkyl side chain and aromatic ring. Furthermore, five specific β- O -4 type lignin dimer model compounds are selected to investigate their integrated pyrolysis mechanism by density functional theory (DFT) methods, to further understand and verify the proposed pyrolysis model. The results indicate that a total of 11 pyrolysis mechanisms, including both concerted mechanisms and homolytic mechanisms, might occur for the initial pyrolysis of the β- O -4 type lignin dimers. Concerted mechanisms are predominant as compared with homolytic mechanisms throughout unimolecular decomposition pathways. The competitiveness of the eleven pyrolysis mechanisms are revealed via different model compounds, and the proposed pyrolysis model is ranked in full consideration of functional groups effects. The proposed pyrolysis model can provide a theoretical basis to predict the reaction pathways and products during the pyrolysis process of β- O -4 type lignin dimers.

A Comprehensive Study on Pyrolysis Mechanism of Substituted β-O-4 Type Lignin Dimers

PubMed Central

Jiang, Xiaoyan; Lu, Qiang; Hu, Bin; Liu, Ji; Dong, Changqing; Yang, Yongping

2017-01-01

In order to understand the pyrolysis mechanism of β-O-4 type lignin dimers, a pyrolysis model is proposed which considers the effects of functional groups (hydroxyl, hydroxymethyl and methoxyl) on the alkyl side chain and aromatic ring. Furthermore, five specific β-O-4 type lignin dimer model compounds are selected to investigate their integrated pyrolysis mechanism by density functional theory (DFT) methods, to further understand and verify the proposed pyrolysis model. The results indicate that a total of 11 pyrolysis mechanisms, including both concerted mechanisms and homolytic mechanisms, might occur for the initial pyrolysis of the β-O-4 type lignin dimers. Concerted mechanisms are predominant as compared with homolytic mechanisms throughout unimolecular decomposition pathways. The competitiveness of the eleven pyrolysis mechanisms are revealed via different model compounds, and the proposed pyrolysis model is ranked in full consideration of functional groups effects. The proposed pyrolysis model can provide a theoretical basis to predict the reaction pathways and products during the pyrolysis process of β-O-4 type lignin dimers. PMID:29120350

Chapter 8: Pyrolysis of Biomass for Aviation Fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robichaud, David J; Jenkins, Rhodri W.; Sutton, Andrew D.

2016-07-15

Pyrolysis, the breaking down of organic material using heat and the absence of oxygen, is a method that has been widely researched for the production of liquid fuels. In this chapter, we review the feedstocks typically used for pyrolysis, the properties and the composition of the liquid fraction (termed 'bio-oil') obtained, the studies in which pyrolysis has been used in an attempt to increase the bio-oil yield, and how the bio-oil has been upgraded to fuel-like molecules. We also discuss the viability of pyrolysis to produce jet fuel hydrocarbons.

Results of the International Energy Agency Round Robin on Fast Pyrolysis Bio-oil Production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elliott, Douglas C.; Meier, Dietrich; Oasmaa, Anja

An international round robin study of the production of fast pyrolysis bio-oil was undertaken. Fifteen institutions in six countries contributed. Three biomass samples were distributed to the laboratories for processing in fast pyrolysis reactors. Samples of the bio-oil produced were transported to a central analytical laboratory for analysis. The round robin was focused on validating the pyrolysis community understanding of production of fast pyrolysis bio-oil by providing a common feedstock for bio-oil preparation. The round robin included: •distribution of 3 feedstock samples from a common source to each participating laboratory; •preparation of fast pyrolysis bio-oil in each laboratory with themore » 3 feedstocks provided; •return of the 3 bio-oil products (minimum 500 ml) with operational description to a central analytical laboratory for bio-oil property determination. The analyses of interest were: density, viscosity, dissolved water, filterable solids, CHN, S, trace element analysis, ash, total acid number, pyrolytic lignin, and accelerated aging of bio-oil. In addition, an effort was made to compare the bio-oil components to the products of analytical pyrolysis through GC/MS analysis. The results showed that clear differences can occur in fast pyrolysis bio-oil properties by applying different reactor technologies or configurations. The comparison to analytical pyrolysis method suggested that Py-GC/MS could serve as a rapid screening method for bio-oil composition when produced in fluid-bed reactors. Furthermore, hot vapor filtration generally resulted in the most favorable bio-oil product, with respect to water, solids, viscosity, and total acid number. These results can be helpful in understanding the variation in bio-oil production methods and their effects on bio-oil product composition.« less

A novel energy-efficient pyrolysis process: self-pyrolysis of oil shale triggered by topochemical heat in a horizontal fixed bed.

PubMed

Sun, You-Hong; Bai, Feng-Tian; Lü, Xiao-Shu; Li, Qiang; Liu, Yu-Min; Guo, Ming-Yi; Guo, Wei; Liu, Bao-Chang

2015-02-06

This paper proposes a novel energy-efficient oil shale pyrolysis process triggered by a topochemical reaction that can be applied in horizontal oil shale formations. The process starts by feeding preheated air to oil shale to initiate a topochemical reaction and the onset of self-pyrolysis. As the temperature in the virgin oil shale increases (to 250-300°C), the hot air can be replaced by ambient-temperature air, allowing heat to be released by internal topochemical reactions to complete the pyrolysis. The propagation of fronts formed in this process, the temperature evolution, and the reaction mechanism of oil shale pyrolysis in porous media are discussed and compared with those in a traditional oxygen-free process. The results show that the self-pyrolysis of oil shale can be achieved with the proposed method without any need for external heat. The results also verify that fractured oil shale may be more suitable for underground retorting. Moreover, the gas and liquid products from this method were characterised, and a highly instrumented experimental device designed specifically for this process is described. This study can serve as a reference for new ideas on oil shale in situ pyrolysis processes.

A Novel Energy-Efficient Pyrolysis Process: Self-pyrolysis of Oil Shale Triggered by Topochemical Heat in a Horizontal Fixed Bed

PubMed Central

Sun, You-Hong; Bai, Feng-Tian; Lü, Xiao-Shu; Li, Qiang; Liu, Yu-Min; Guo, Ming-Yi; Guo, Wei; Liu, Bao-Chang

2015-01-01

This paper proposes a novel energy-efficient oil shale pyrolysis process triggered by a topochemical reaction that can be applied in horizontal oil shale formations. The process starts by feeding preheated air to oil shale to initiate a topochemical reaction and the onset of self-pyrolysis. As the temperature in the virgin oil shale increases (to 250–300°C), the hot air can be replaced by ambient-temperature air, allowing heat to be released by internal topochemical reactions to complete the pyrolysis. The propagation of fronts formed in this process, the temperature evolution, and the reaction mechanism of oil shale pyrolysis in porous media are discussed and compared with those in a traditional oxygen-free process. The results show that the self-pyrolysis of oil shale can be achieved with the proposed method without any need for external heat. The results also verify that fractured oil shale may be more suitable for underground retorting. Moreover, the gas and liquid products from this method were characterised, and a highly instrumented experimental device designed specifically for this process is described. This study can serve as a reference for new ideas on oil shale in situ pyrolysis processes. PMID:25656294

Mn-doping-induced photocatalytic activity enhancement of ZnO nanorods prepared on glass substrates

NASA Astrophysics Data System (ADS)

Putri, Nur Ajrina; Fauzia, Vivi; Iwan, S.; Roza, Liszulfah; Umar, Akrajas Ali; Budi, Setia

2018-05-01

Mn-doped ZnO nanorods were synthesized on glass substrates via a two-steps process of ultrasonic spray pyrolysis and hydrothermal methods with four different concentrations Mn-doping (0, 1, 3, and 7 mol%). Introduction of Mn into ZnO is known could enhance the photocatalytic activity owing to the increase in the defect sites that effectively suppress the recombination of free electrons and holes. In this study, results show that Mn-doping has effectively modified the nucleations and crystal growth of ZnO, as evidenced by the increasing in the diameter, height, and the number of nanorods per unit area, besides slightly reduced the band gap and increased the oxygen vacancy concentrations in the ZnO lattice. This condition has successfully multiplied the photocatalytic performance of the ZnO nanorods in the degradation of methylene blue (MB) compared to the undoped-ZnO sample where in the typical process the MB can be degraded approximately 77% within only 35 min under a UV light irradiation.

Praseodymium - A Competent Dopant for Luminescent Downshifting and Photocatalysis in ZnO Thin Films

NASA Astrophysics Data System (ADS)

Narayanan, Nripasree; Deepak, N. K.

2018-05-01

Highly transparent and conducting Zinc oxide (ZnO) thin films doped with Praseodymium (Pr) were deposited on glass substrates by using the spray pyrolysis method. The X-ray diffraction (XRD) analysis revealed the polycrystallinity of the deposited films with a hexagonal wurtzite structure, whereas the energy-dispersive X-ray spectroscopy (EDX) analysis confirmed the incorporation of Pr in the films. The optical energy gap decreased by Pr doping due to the merging of the conduction band with the impurity bands formed within the forbidden gap. The room temperature photoluminescence spectra of the Pr-doped film showed enhancement of visible emission, suggesting efficient luminescent downshifting. The photocatalytic activity of the Pr-doped films is higher than that of undoped films due to the effective suppression of the rapid recombination of the photo-generated electron-hole pairs. The impurity levels formed within the forbidden gap act as efficient luminescent centers and electron traps, which lead to luminescent downshifting and enhanced photocatalytic activity.

Survival of Staphylococcus aureus exposed to UV radiation on the surface of ceramic tiles coated with TiO2.

PubMed

Szczawiński, J; Tomaszewski, H; Jackowska-Tracz, A; Szczawińska, M E

2011-01-01

The aim of this study was to determine and compare the antimicrobial activity of UV radiation of wavelength 253.7 nm (used in typical germicidal lamps) against Staphylococcus aureus on the surfaces of conventionally produced white ceramic wall tiles (matt and shiny) and the same tiles coated with TiO2 using three different methods: RF diode sputtering, atmospheric pressure chemical vapour deposition (APCVD) and spray pyrolysis deposition (SPD). Results clearly indicate that the bactericidal action of UV radiation is much stronger on the surfaces of tiles coated with TiO2 than on the tiles uncovered. The strongest bactericidal effect of UV radiation was found for film prepared by APCVD. Results of experiments for shiny and matt tiles did not differ statistically. The use of ceramic wall tiles coated with TiO2 films in hospitals, veterinary clinics, laboratories, food processing plants and other places where UV radiation is applied for disinfection should greatly improve the efficiency of this treatment.

CH₃NH₃PbI₃-based planar solar cells with magnetron-sputtered nickel oxide.

PubMed

Cui, Jin; Meng, Fanping; Zhang, Hua; Cao, Kun; Yuan, Huailiang; Cheng, Yibing; Huang, Feng; Wang, Mingkui

2014-12-24

Herein we report an investigation of a CH3NH3PbI3 planar solar cell, showing significant power conversion efficiency (PCE) improvement from 4.88% to 6.13% by introducing a homogeneous and uniform NiO blocking interlayer fabricated with the reactive magnetron sputtering method. The sputtered NiO layer exhibits enhanced crystallization, high transmittance, and uniform surface morphology as well as a preferred in-plane orientation of the (200) plane. The PCE of the sputtered-NiO-based perovskite p-i-n planar solar cell can be further promoted to 9.83% when a homogeneous and dense perovskite layer is formed with solvent-engineering technology, showing an impressive open circuit voltage of 1.10 V. This is about 33% higher than that of devices using the conventional spray pyrolysis of NiO onto a transparent conducting glass. These results highlight the importance of a morphology- and crystallization-compatible interlayer toward a high-performance inverted perovskite planar solar cell.

Effect of Catalytic Pyrolysis Conditions Using Pulse Current Heating Method on Pyrolysis Products of Wood Biomass

PubMed Central

Honma, Sensho; Hata, Toshimitsu; Watanabe, Takashi

2014-01-01

The influence of catalysts on the compositions of char and pyrolysis oil obtained by pyrolysis of wood biomass with pulse current heating was studied. The effects of catalysts on product compositions were analyzed using GC-MS and TEM. The compositions of some aromatic compounds changed noticeably when using a metal oxide species as the catalyst. The coexistence or dissolution of amorphous carbon and iron oxide was observed in char pyrolyzed at 800°C with Fe3O4. Pyrolysis oil compositions changed remarkably when formed in the presence of a catalyst compared to that obtained from the uncatalyzed pyrolysis of wood meal. We observed a tendency toward an increase in the ratio of polyaromatic hydrocarbons in the pyrolysis oil composition after catalytic pyrolysis at 800°C. Pyrolysis of biomass using pulse current heating and an adequate amount of catalyst is expected to yield a higher content of specific polyaromatic compounds. PMID:25614894

A Comparative study of microwave-induced pyrolysis of lignocellulosic and algal biomass.

PubMed

Wang, Nan; Tahmasebi, Arash; Yu, Jianglong; Xu, Jing; Huang, Feng; Mamaeva, Alisa

2015-08-01

Microwave (MW) pyrolysis of algal and lignocellulosic biomass samples were studied using a modified domestic oven. The pyrolysis temperature was recorded continuously by inserting a thermocouple into the samples. Temperatures as high as 1170 and 1015°C were achieved for peanut shell and Chlorella vulgaris. The activation energy for MW pyrolysis was calculated by Coats-Redfern method and the values were 221.96 and 214.27kJ/mol for peanut shell and C. vulgaris, respectively. Bio-oil yields reached to 27.7wt.% and 11.0wt.% during pyrolysis of C. vulgaris and peanut shell, respectively. The bio-oil samples from pyrolysis were analyzed by a gas chromatography-mass spectrometry (GC-MS). Bio-oil from lignocellulosic biomass pyrolysis contained more phenolic compounds while that from microalgae pyrolysis contained more nitrogen-containing species. Fourier transform infrared spectroscopy (FTIR) analysis results showed that concentration of OH, CH, CO, OCH3, and CO functional groups in char samples decreased significantly after pyrolysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Melioration of Optical and Electrical Performance of Ga-N Codoped ZnO Thin Films

NASA Astrophysics Data System (ADS)

Narayanan, Nripasree; Deepak, N. K.

2018-06-01

Transparent and conducting p-type zinc oxide (ZnO) thin films doped with gallium (Ga) and nitrogen (N) simultaneously were deposited on glass substrates by spray pyrolysis technique. Phase composition analysis by X-ray diffraction confirmed the polycrystallinity of the films with pure ZnO phase. Energy dispersive X-ray analysis showed excellent incorporation of N in the ZnO matrix by means of codoping. The optical transmittance of N monodoped film was poor but got improved with Ga-N codoping and also resulted in the enhancement of optical energy gap. Hole concentration increased with codoping and consequently, lower resistivity and high stability were obtained.

Review of NMR characterization of pyrolysis oils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hao, Naijia; Ben, Haoxi; Yoo, Chang Geun

Here, pyrolysis of renewable biomass has been developed as a method to produce green fuels and chemicals in response to energy security concerns as well as to alleviate environmental issues incurred with fossil fuel usage. However, pyrolysis oils still have limited commercial application, mainly because unprocessed oils cannot be readily blended with current petroleum-based transportation fuels. To better understand these challenges, researchers have applied diverse characterization techniques in the development of bio-oil studies. In particular, nuclear magnetic resonance (NMR) is a key spectroscopic characterization method through analysis of bio-oil components. This review highlights the NMR strategies for pyrolysis oil characterizationmore » and critically discusses the applications of 1H, 13C, 31P, 19F, and two-dimensional (2-D NMR) analyses such as heteronuclear single quantum correlation (HSQC) in representative pyrolysis oil studies.« less

Review of NMR characterization of pyrolysis oils

DOE PAGES

Hao, Naijia; Ben, Haoxi; Yoo, Chang Geun; ...

2016-08-24

Here, pyrolysis of renewable biomass has been developed as a method to produce green fuels and chemicals in response to energy security concerns as well as to alleviate environmental issues incurred with fossil fuel usage. However, pyrolysis oils still have limited commercial application, mainly because unprocessed oils cannot be readily blended with current petroleum-based transportation fuels. To better understand these challenges, researchers have applied diverse characterization techniques in the development of bio-oil studies. In particular, nuclear magnetic resonance (NMR) is a key spectroscopic characterization method through analysis of bio-oil components. This review highlights the NMR strategies for pyrolysis oil characterizationmore » and critically discusses the applications of 1H, 13C, 31P, 19F, and two-dimensional (2-D NMR) analyses such as heteronuclear single quantum correlation (HSQC) in representative pyrolysis oil studies.« less

Method of increasing anhydrosugars, pyroligneous fractions and esterified bio-oil

DOEpatents

Steele, Philip H; Yu, Fei; Li, Qi; Mitchell, Brian

2014-12-30

The device and method are provided to increase anhydrosugars yield during pyrolysis of biomass. This increase is achieved by injection of a liquid or gas into the vapor stream of any pyrolysis reactor prior to the reactor condensers. A second feature of our technology is the utilization of sonication, microwave excitation, or shear mixing of the biomass to increase the acid catalyst rate for demineralization or removal of hemicellulose prior to pyrolysis. The increased reactivity of these treatments reduces reaction time as well as the required amount of catalyst to less than half of that otherwise required. A fractional condensation system employed by our pyrolysis reactor is another feature of our technology. This system condenses bio-oil pyrolysis vapors to various desired fractions by differential temperature manipulation of individual condensers comprising a condenser chain.

Catalytic cracking of fast and tail gas reactive pyrolysis bio-oils over HZSM-5

USDA-ARS?s Scientific Manuscript database

While hydrodeoxygenation (HDO) of pyrolysis oil is well understood as an upgrading method, the high processing pressures associated with it alone justify the exploration of alternative upgrading solutions, especially those that could adapt pyrolysis oils into the existing refinery infrastructure. Ca...

Comparison of artificial maturation of lignite in hydrous and nonhydrous conditions

USGS Publications Warehouse

Behar, F.; Lewan, M.D.; Lorant, F.; Vandenbroucke, M.

2003-01-01

The objectives of the study are to compare product compositions and yields generated from lignite artificially matured by open nonhydrous pyrolysis, closed nonhydrous pyrolysis, and hydrous pyrolysis. The pyrolysis products were fractionated into CO2, H2O, CH4, C2-C5, C8-C14, C14+ saturates, C14+ aromatics and NSOs (resins+asphaltenes). All three methods generated high and similar quantities of water during pyrolysis that ranged between 14.6 and 15.2 wt.% of the original lignite. As a result of this high water content generated by the lignite, the experiments with no added water are referred to as nonhydrous rather than anhydrous. Rock-Eval pyrolysis and elemental analyses were conducted on the recovered lignite after solvent extraction to determine their residual hydrocarbon generation potential and to plot their position in a van Krevelen diagram, respectively. Residual lignite from the closed nonhydrous and hydrous experiments showed relationships between vitrinite reflectance (%Ro) values and atomic H/C ratios that occurred within the fields observed for natural maturation of coal. Although no significant differences in the atomic H/C ratios were observed between closed nonhydrous and hydrous pyrolysis, the vitrinite reflectance values were on the average 0.2% Ro lower in the residual lignite from the nonhydrous experiments. The remaining hydrocarbon generation potential as determined by Rock-Eval pyrolysis of the residual lignite showed that the nonhydrous residuals had on the average 16 mg more hydrocarbon potential per gram of original lignite than the hydrous residuals. This suggests there is a better release of the pyrolysis products from the lignite network in the hydrous experiments once generation occurs. For gas generation, at maximum yields, open nonhydrous pyrolysis generates the most hydrocarbon gas (21.0 mg/g original lignite), which is 20% more than closed nonhydrous pyrolysis and 29% more than hydrous pyrolysis. Closed nonhydrous pyrolysis generates on the average 14% more gas than hydrous pyrolysis, but the proportionality of the generated hydrocarbon gases is essentially the same for both pyrolysis methods. At maximum yields, CO2 generation is greatest in hydrous pyrolysis (99.5 mg/g original lignite), with yields being 37 percent higher than closed nonhydrous pyrolysis and 26% higher than open nonhydrous pyrolysis. The maximum yields of C14+ products are highest and similar for open nonhydrous pyrolysis and hydrous pyrolysis (125.6 and 125.9 mg/g lignite, respectively), and are more than 70% higher than closed nonhydrous pyrolysis. This difference in the maximum yields of C14+ products can be explained by differences in the proportionality between either cracking reactions that result in liquid product and char formation or trapping of generated products within the coal network (cross-linking reactions). Maximum yields of C14+ aliphatics from hydrous experiments may not have been attained, but the maximums that were observed and their GC traces are similar for the three pyrolysis systems.

Self-activation of biochar from furfural residues by recycled pyrolysis gas.

PubMed

Yin, Yulei; Gao, Yuan; Li, Aimin

2018-04-17

Biochar samples with controllable specific surface area and mesopore ratio were self-activated from furfural residues by recycled pyrolysis gas. The objective of this study was to develop a new cyclic utilization method for the gas produced by pyrolysis. The influences of preparation parameters on the resulting biochar were studied by varying the pyrolysis-gas flow rate, activation time and temperature. Structural characterization of the produced biochar was performed by analysis of nitrogen adsorption isotherms at 77 K and scanning electron microscope (SEM). The pyrolysis gas compositions before and after activation were determined by a gas chromatograph. The results indicated that the surface area of the biochar was increased from 167 m 2 /g to 567 m 2 /g, the total pore volume increased from 0.121 cm 3 /g to 0.380 cm 3 /g, and the ratio of the mesopore pore volume to the total pore volume increased 17-39.7%. The CO volume fraction of the pyrolysis gas changed from 34.66 to 62.29% and the CO 2 volume fraction decreased from 48.26% to 12.17% under different conditions of pyrolysis-gas flow rate, activation time and temperature. The calorific values of pyrolysis gas changed from 8.82 J/cm 3 to 14.00 J/cm 3 , which were higher than those of conventional pyrolysis gases. The slower pyrolysis-gas flow rate and higher activation time increased the efficiency of the reaction between carbon and pyrolysis gas. These results demonstrated the feasibility of treatment of the furfural residues to produce microporous and mesoporous biochar. The pyrolysis gas that results from the activation process could be used as fuel. Overall, this new self-activation method meets the development requirements of cyclic economy and cleaner production. Copyright © 2018. Published by Elsevier Ltd.

Study of sensing properties of SnO2 prepared by spray-pyrolysis deposition towards ethanol gas

NASA Astrophysics Data System (ADS)

Saadaldin, Nasser M.; Hussain, Nabiha; AlZouabi, Abla

2018-05-01

Ethanol is widely used in all kinds of products with direct exposure to the human skin (e.g. medicinal products like hand disinfectants in occupational settings, cosmetics like hairsprays or mouthwashes, in this study, thin films of (SnO2) were deposited by using the thermal spray method (SPD) on quartz at 450°C substrate temperature using tin chloride SnCl2.2H2O, (1.0M). A gas sensor was constructed with the prepared SnO2, used to detect ethanol gas and some other gases. The films were characterized by X-ray diffraction (XRD), and scanning electron microscopy (SEM). The grain size was calculated the results showed nanostructure polycrystalline and crystallize in a tetragonal, S.G:P42/m nm, reaching grain Size approximately 27nm. The sensing properties of the films were studied towards ethanol at different concentrations ranging within (1-200 ppm,) the results showed that the sensitivity of the film increases with the concentration of ethanol, the best operating temperature reached about 300 °C, We studied the sensing properties of the films towards Ethanol alcohol gas, The first and foremost concerns of topical ethanol applications for public health are its carcinogenic effects, high selectivity and sensitivity of the film towards ethanol gas was found compared to other tested toxic gases such as methanol gas, acetone and methylbenzene. Yet an upto-date risk assessment of ethanol application on the skin and inside the oral cavity is currently lacking.

An investigation of the Nb doping effect on structural, morphological, electrical and optical properties of spray deposited F doped SnO2 films

NASA Astrophysics Data System (ADS)

Turgut, G.; Keskenler, E. F.; Aydın, S.; Yılmaz, M.; Doǧan, S.; Düzgün, B.

2013-03-01

F and Nb + F co-doped SnO2 thin films were deposited on glass substrates by the spray pyrolysis method. The microstructural, morphological, electrical and optical properties of the 10 wt% F doped SnO2 (FTO) thin films were investigated specifically for niobium (Nb) doping in the range of 0-4 at.% with 1 at.% steps. As shown by the x-ray diffraction patterns, the films exhibited a tetragonal cassiterite structure with (200) preferential orientation. It was observed that grain sizes of the films for (200) and (301) peaks depended on the Nb doping concentration and varied in the range of 25.11-32.19 and 100.6-183.7 nm, respectively. The scanning electron microscope (SEM) micrographs showed that the FTO films were made of small pyramidal grains, while doubly doped films were made of small pyramidal grains and big polyhedron grains. From electrical studies, although 1 at.% Nb doped FTO films have the lowest sheet resistance and resistivity values, the highest figure-of-merit and optical band gap values obtained for FTO films were 16.2 × 10-2 Ω-1 and 4.21 eV, respectively. Also, infrared reflectivity values of the films were in the range of 97.39-98.98%. These results strongly suggest that these films are an attractive candidate for various optoelectronic applications and for photothermal conversion of solar energy.

High density Polyethylene plastic waste treatment with microwave heating pyrolysis method using coconut-shell activated carbon to produce alternative fuels

NASA Astrophysics Data System (ADS)

Juliastuti, S. R.; Hisbullah, M. I.; Abdillah, M.

2018-03-01

Pyrolysis is a technology that could crack polimer such as plastic waste into alternative fuels. This research uses microwave heating methode, which more efficient than conventional heating methode. The plastic waste used is 200 grams of HDPE, with feed to catalyst weight ratio are 1:1, 0.6:1, 0.4:1. Pyrolysis was run at temperatures of 250, 300, 350, & 400 °C for 15, 30 and 45 min. From the experimental result, the best variable of pyrolysis process with microwave method is at 45 minutes, at 400°C, and 1:1 feed to catalyst weight ratio. Result shows that yield of liquid and gas product is 99.22%; yield of residue is 0.78%; value of liquid product’s composition (cycloparaffin and n-paraffin) is 54.09% and concentration of methane gas is 10.2%.

Pyrolysis and catalytic pyrolysis as a recycling method of waste CDs originating from polycarbonate and HIPS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Antonakou, E.V.; Kalogiannis, K.G.; Stephanidis, S.D.

Highlights: • Thermal and catalytic pyrolysis is a powerful method for recycling of WEEEs. • Liquid products obtained from the pyrolysis of PC or HIPS found in waste CDs are very different. • Mainly phenols are obtained from pyrolysis PC based wastes while aromatics from HIPS. • Use of MgO catalyst increases the amount of phenols from CD recycling compared to ZSM-5. • Use of MgO or ZSM-5 catalysts reduces the amount of styrene recovered from HIPS. - Abstract: Pyrolysis appears to be a promising recycling process since it could convert the disposed polymers to hydrocarbon based fuels or variousmore » useful chemicals. In the current study, two model polymers found in WEEEs, namely polycarbonate (PC) and high impact polystyrene (HIPS) and their counterparts found in waste commercial Compact Discs (CDs) were pyrolysed in a bench scale reactor. Both, thermal pyrolysis and pyrolysis in the presence of two catalytic materials (basic MgO and acidic ZSM-5 zeolite) was performed for all four types of polymers. Results have shown significant recovery of the monomers and valuable chemicals (phenols in the case of PC and aromatic hydrocarbons in the case of HIPS), while catalysts seem to decrease the selectivity towards the monomers and enhance the selectivity towards other desirable compounds.« less

Bacterial biomarkers thermally released from dissolved organic matter

USGS Publications Warehouse

Greenwood, P.F.; Leenheer, J.A.; McIntyre, C.; Berwick, L.; Franzmann, P.D.

2006-01-01

Hopane biomarker products were detected using microscale sealed vessel (MSSV) pyrolysis gas chromatography-mass spectrometry (GC-MS) analysis of dissolved organic matter from natural aquatic systems colonised by bacterial populations. MSSV pyrolysis can reduce the polyhydroxylated alkyl side chain of bacteriohopanepolyols, yielding saturated hopane products which are more amenable to GC-MS detection than their functionalised precursors. This example demonstrates how the thermal conditions of MSSV pyrolysis can reduce the biologically-inherited structural functionality of naturally occurring organic matter such that additional structural fragments can be detected using GC methods. This approach complements traditional analytical pyrolysis methods by providing additional speciation information useful for establishing the structures and source inputs of recent or extant organic material. ?? 2006.

Requirements for transportation of fast pyrolysis bio-oil in Finland

NASA Astrophysics Data System (ADS)

Karhunen, Antti; Laihanen, Mika; Ranta, Tapio

2016-11-01

The purpose of this paper is to discuss the requirements and challenges of pyrolysis oil's transportation in Finland. Pyrolysis oil is a new type of renewable liquid fuel that can be utilised in applications such as heat and electricity production. It has never been transported on a large scale in Finland. Possible options are transport by road, rail and waterway. The most significant requirements in its transportation are created by acidity and high density of pyrolysis oil, which impose requirements for the materials and transport equipment. The study described here shows that constant domestic transportation of pyrolysis oil is most reasonably operated with tank trucks. Rail-based transport may have potential for domestic fixed routes, and transport by water could be utilised in exporting. All transportation methods have limitations and advantages relative to each other. Ultimately, the production site and end-user's locations will determine the most suitable transport method.

Kinetics of coffee industrial residue pyrolysis using distributed activation energy model and components separation of bio-oil by sequencing temperature-raising pyrolysis.

PubMed

Chen, Nanwei; Ren, Jie; Ye, Ziwei; Xu, Qizhi; Liu, Jingyong; Sun, Shuiyu

2016-12-01

This study was carried out to investigate the kinetics of coffee industrial residue (CIR) pyrolysis, the effect of pyrolysis factors on yield of bio-oil component and components separation of bio-oil. The kinetics of CIR pyrolysis was analyzed using distributed activation energy model (DAEM), based on the experiments in thermogravimetric analyzer (TGA), and it indicated that the average of activation energy (E) is 187.86kJ·mol -1 . The bio-oils were prepared from CIR pyrolysis in vacuum tube furnace, and its components were determined by gas chromatography/mass spectrometry (GC-MS). Among pyrolysis factors, pyrolysis temperature is the most influential factor on components yield of bio-oil, directly concerned with the volatilization and yield of components (palmitic acid, linoleic acid, oleic acid, octadecanoic acid and caffeine). Furthermore, a new method (sequencing temperature-raising pyrolysis) was put forward and applied to the components separation of bio-oil. Based on experiments, a solution of components separation of bio-oil was come out. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reducing the bioavailability and leaching potential of lead in contaminated water hyacinth biomass by phosphate-assisted pyrolysis.

PubMed

Shi, Lingna; Wang, Lijun; Zhang, Tao; Li, Jianfa; Huang, Xiaoyi; Cai, Jing; Lü, Jinhong; Wang, Yue

2017-10-01

For the purpose of safe disposal of biomass contaminated by biosorption of heavy metals, phosphate-assisted pyrolysis of water hyacinth biomass contaminated by lead (Pb) was tried to reduce the bioavailability and leaching potential of Pb, using direct pyrolysis without additive as a control method. Direct pyrolysis of the contaminated biomass at low temperatures (300 and 400°C) could reduce the bioavailability of Pb, but the leaching potential of Pb was increased with the rising pyrolysis temperature. While phosphate-assisted pyrolysis significantly enhanced the recovery and stability of Pb in the char. Specifically, the percentages of bioavailable Pb and leachable Pb in the chars obtained by phosphate-assisted pyrolysis at low temperatures were reduced to less than 5% and 7%, respectively. The sequential extraction test indicated the transformation of Pb into more stable fractions after phosphate-assisted pyrolysis, which was related to the formation of Pb phosphate minerals including pyromorphite and lead-substituted hydroxyapatite. Copyright © 2017 Elsevier Ltd. All rights reserved.

Investigation of waste biomass co-pyrolysis with petroleum sludge using a response surface methodology.

PubMed

Hu, Guangji; Li, Jianbing; Zhang, Xinying; Li, Yubao

2017-05-01

The treatment of waste biomass (sawdust) through co-pyrolysis with refinery oily sludge was carried out in a fixed-bed reactor. Response surface method was applied to evaluate the main and interaction effects of three experimental factors (sawdust percentage in feedstock, temperature, and heating rate) on pyrolysis oil and char yields. It was found that the oil and char yields increased with sawdust percentage in feedstock. The interaction between heating rate and sawdust percentage as well as between heating rate and temperature was significant on the pyrolysis oil yield. The higher heating value of oil originated from sawdust during co-pyrolysis at a sawdust/oily sludge ratio of 3:1 increased by 5 MJ/kg as compared to that during sawdust pyrolysis alone, indicating a synergistic effect of co-pyrolysis. As a result, petroleum sludge can be used as an effective additive in the pyrolysis of waste biomass for improving its energy recovery. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of fluorine doping on highly transparent conductive spray deposited nanocrystalline tin oxide thin films

NASA Astrophysics Data System (ADS)

Moholkar, A. V.; Pawar, S. M.; Rajpure, K. Y.; Bhosale, C. H.; Kim, J. H.

2009-09-01

The undoped and fluorine doped thin films are synthesized by using cost-effective spray pyrolysis technique. The dependence of optical, structural and electrical properties of SnO 2 films, on the concentration of fluorine is reported. Optical absorption, X-ray diffraction, scanning electron microscope (SEM) and Hall effect studies have been performed on SnO 2:F (FTO) films coated on glass substrates. The film thickness varies from 800 to 1572 nm. X-ray diffraction pattern reveals the presence of cassiterite structure with (2 0 0) preferential orientation for FTO films. The crystallite size varies from 35 to 66 nm. SEM and AFM study reveals the surface of FTO to be made of nanocrystalline particles. The electrical study reveals that the films are degenerate and exhibit n-type electrical conductivity. The 20 wt% F doped film has a minimum resistivity of 3.8 × 10 -4 Ω cm, carrier density of 24.9 × 10 20 cm -3 and mobility of 6.59 cm 2 V -1 s -1. The sprayed FTO film having minimum resistance of 3.42 Ω/cm 2, highest figure of merit of 6.18 × 10 -2 Ω -1 at 550 nm and 96% IR reflectivity suggest, these films are useful as conducting layers in electrochromic and photovoltaic devices and also as the passive counter electrode.

Characterization of carbon silica hybrid fillers obtained by pyrolysis of waste green tires by the STEM–EDX method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Hartomy, Omar A.; Department of Physics, Faculty of Science, University of Tabuk, Tabuk 71491; Al-Ghamdi, Ahmed A.

2015-03-15

Dual phase carbon–silica hybrid fillers obtained by pyrolysis-cum-water vapor of waste green tires have been characterized by energy dispersive X-ray spectroscopy in a scanning transmission electron microscope, silicate analysis, weight analysis, atomic absorption spectroscopy and by inductively coupled plasma–optical emission spectroscopy. The results achieved have shown that the location and distribution of the phases in the carbon silica hybrid fillers as well as their most essential characteristics are influenced by the pyrolysis conditions. The carbon phase of the filler thus obtained is located predominantly in the space among silica aggregates which have already been existing while it has been formedmore » by elastomer destruction in the course of pyrolysis. The presence of ZnS also has been found in the hybrid fillers investigated. - Highlights: • Dual phase fillers obtained by pyrolysis of waste green tires have been characterized. • The STEM–EDX method was used for characterization. • The phase distributions in the fillers are influenced by the pyrolysis conditions.« less

Evaluation of agricultural residues pyrolysis under non-isothermal conditions: Thermal behaviors, kinetics, and thermodynamics.

PubMed

Chen, Jianbiao; Wang, Yanhong; Lang, Xuemei; Ren, Xiu'e; Fan, Shuanshi

2017-10-01

The thermal conversion characteristics, kinetics, and thermodynamics of agricultural residues, rape straw (RS) and wheat bran (WB), were investigated under non-isothermal conditions. TGA experiments showed that the pyrolysis characteristics of RS were quite different from those of WB. As reflected by the comprehensive devolatilization index, when the heating rate increased from 10 to 30Kmin -1 , the pyrolysis performance of RS and WB were improved 5.27 and 5.96 times, respectively. The kinetic triplets of the main pyrolysis process of agricultural residues were calculated by the Starink method and the integral master-plots method. Kinetic analysis results indicated that the most potential kinetic models for the pyrolysis of RS and WB were D 2 and F 2.7 , respectively. The thermodynamic parameters (ΔH, ΔG, and ΔS) were determined by the activated complex theory. The positive ΔH, positive ΔG, and negative ΔS at characteristic temperatures validated that the pyrolysis of agricultural residues was endothermic and non-spontaneous. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pseudo-Capacitors: SPPS Deposition and Electrochemical Analysis of α-MoO3 and Mo2N Coatings

NASA Astrophysics Data System (ADS)

Golozar, Mehdi; Chien, Ken; Lian, Keryn; Coyle, Thomas W.

2013-06-01

Solution precursor plasma spraying (SPPS) is a novel thermal spray process in which a solution precursor is injected into the high-temperature zone of a DC-arc plasma jet to allow solvent evaporation from the precursor droplets, solute precipitation, and precipitate pyrolysis prior to substrate impact. This investigation explored the potential of SPPS to fabricate α-MoO3 coatings with fine grain sizes, high porosity levels, and high surface area: characteristics needed for application as pseudo-capacitor electrodes. Since molybdenum nitride has shown a larger electrochemical stability window and higher specific area capacitance, the α-MoO3 deposits were subsequently converted into molybdenum nitride. A multistep heat-treatment procedure resulted in a topotactic phase-transformation mechanism, which retained the high surface area lath-shaped features of the original α-MoO3. The electrochemical behaviors of molybdenum oxide and molybdenum nitride deposits formed under different deposition conditions were studied using cyclic voltammetry to assess the influence of the resulting microstructure on the charge storage behavior and potential for use in pseudo-capacitors.

Visible light assisted photoelectrocatalytic degradation of sugarcane factory wastewater by sprayed CZTS thin films

NASA Astrophysics Data System (ADS)

Hunge, Y. M.; Mahadik, M. A.; Patil, V. L.; Pawar, A. R.; Gadakh, S. R.; Moholkar, A. V.; Patil, P. S.; Bhosale, C. H.

2017-12-01

Highly crystalline Cu2ZnSnS4 (CZTS) thin films have been deposited onto glass and FTO coated glass substrates by simple chemical spray-pyrolysis technique. It is an important material for solar energy conversion through the both photovoltaics and photocatalysis. The effect of substrate temperatures on the physico-chemical properties of the CZTS films is studied. The XRD study shows the formation of single phase CZTS with kesterite structure. FE-SEM analysis reveals nano flakes architecture with pin-hole and crake free surface with more adherent. The film deposited at optimized substrate temperature exhibits optical band gap energy of 1.90 eV, which lies in the visible region of the solar spectrum and useful for photocatalysis application. The photoelectrocatalytic activities of the large surface area (10 × 10 cm2) deposited CZTS thin film photocatalysts were evaluated for the degradation of sugarcane factory wastewater under visible light irradiation. The results show that the CZTS thin film photocatalyst exhibited about 90% degradation of sugar cane factory wastewater. The mineralization of sugarcane factory wastewater is studied by measuring chemical oxygen demand (COD) values.

Small-scale hydrous pyrolysis of macromolecular material in meteorites

NASA Astrophysics Data System (ADS)

Sephton, M. A.; Pillinger, C. T.; Gilmour, I.

1998-12-01

The hydrous pyrolysis method, usually performed on several hundred grams of terrestrial rock sample, has been scaled down to accommodate less than two grams of meteorite sample. This technique makes full use of the high yields associated with hydrous pyrolysis experiments and permits the investigation of the meteorite macromolecular material, the major organic component in carbonaceous meteorites. The hydrous pyrolysis procedure transforms the high molecular weight macromolecular material into low molecular weight fragments. The released entities can then be extracted with supercritical fluid extraction. In contrast to the parent structure, the pyrolysis products are amenable for analysis by gas chromatography-based techniques. When subjected to hydrous pyrolysis, two carbonaceous chondrites (Orgueil and Cold Bokkeveld) released generally similar products, which consisted of abundant volatile aromatic and alkyl-substituted aromatic compounds. These results revealed the ability of small-scale hydrous pyrolysis to dissect extraterrestrial macromolecular material and thereby reveal its organic constitution.

Concentration-response data on toxicity of pyrolysis gases from some natural and synthetic polymers

NASA Technical Reports Server (NTRS)

Hilado, C. J.; Huttlinger, N. V.

1978-01-01

Concentration-response data are presented on the toxic effects of the pyrolysis gases from some natural and synthetic polymers, using the toxicity screening test method developed at the University of San Francisco. The pyrolysis gases from wool, red oak, Douglas fir, polycaprolactam, polyether sulfone, polyaryl sulfone, and polyphenylene sulfide appeared to exhibit the concentration-response relationships commonly encountered in toxicology. Carbon monoxide seemed to be an important toxicant in the pyrolysis gases from red oak, Douglas fir, and polycaprolactam, but did not appear to have been the principal toxicant in the pyrolysis gases from polyether sulfone and polyphenylene sulfide.

Pyrolysis reaction models of waste tires: Application of Master-Plots method for energy conversion via devolatilization.

PubMed

Irmak Aslan, Dilan; Parthasarathy, Prakash; Goldfarb, Jillian L; Ceylan, Selim

2017-10-01

Land applied disposal of waste tires has far-reaching environmental, economic, and human health consequences. Pyrolysis represents a potential waste management solution, whereby the solid carbonaceous residue is heated in the absence of oxygen to produce liquid and gaseous fuels, and a solid char. The design of an efficient conversion unit requires information on the reaction kinetics of pyrolysis. This work is the first to probe the appropriate reaction model of waste tire pyrolysis. The average activation energy of pyrolysis was determined via iso-conversional methods over a mass fraction conversion range between 0.20 and 0.80 to be 162.8±23.2kJmol -1 . Using the Master Plots method, a reaction order of three was found to be the most suitable model to describe the pyrolytic decomposition. This suggests that the chemical reactions themselves (cracking, depolymerization, etc.), not diffusion or boundary layer interactions common with carbonaceous biomasses, are the rate-limiting steps in the pyrolytic decomposition of waste tires. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microwave pyrolysis using self-generated pyrolysis gas as activating agent: An innovative single-step approach to convert waste palm shell into activated carbon

NASA Astrophysics Data System (ADS)

Yek, Peter Nai Yuh; Keey Liew, Rock; Shahril Osman, Mohammad; Chung Wong, Chee; Lam, Su Shiung

2017-11-01

Waste palm shell (WPS) is a biomass residue largely available from palm oil industries. An innovative microwave pyrolysis method was developed to produce biochar from WPS while the pyrolysis gas generated as another product is simultaneously used as activating agent to transform the biochar into waste palm shell activated carbon (WPSAC), thus allowing carbonization and activation to be performed simultaneously in a single-step approach. The pyrolysis method was investigated over a range of process temperature and feedstock amount with emphasis on the yield and composition of the WPSAC obtained. The WPSAC was tested as dye adsorbent in removing methylene blue. This pyrolysis approach provided a fast heating rate (37.5°/min) and short process time (20 min) in transforming WPS into WPSAC, recording a product yield of 40 wt%. The WPSAC was detected with high BET surface area (≥ 1200 m2/g), low ash content (< 5 wt%), and high pore volume (≥ 0.54 cm3/g), thus recording high adsorption efficiency of 440 mg of dye/g. The desirable process features (fast heating rate, short process time) and the recovery of WPSAC suggest the exceptional promise of the single-step microwave pyrolysis approach to produce high-grade WPSAC from WPS.

Toxicity of pyrolysis gases from polyether sulfone

NASA Technical Reports Server (NTRS)

Hilado, C. J.; Olcomendy, E. M.

1979-01-01

A sample of polyether sulfone was evaluated for toxicity of pyrolysis gases, using the toxicity screening test method developed at the University of San Francisco. Animal response times were relatively short at pyrolysis temperatures of 600 to 800 C, with death occurring within 6 min. The principal toxicant appeared to be a compound other than carbon monoxide.

Kinetic compensation effect in logistic distributed activation energy model for lignocellulosic biomass pyrolysis.

PubMed

Xu, Di; Chai, Meiyun; Dong, Zhujun; Rahman, Md Maksudur; Yu, Xi; Cai, Junmeng

2018-06-04

The kinetic compensation effect in the logistic distributed activation energy model (DAEM) for lignocellulosic biomass pyrolysis was investigated. The sum of square error (SSE) surface tool was used to analyze two theoretically simulated logistic DAEM processes for cellulose and xylan pyrolysis. The logistic DAEM coupled with the pattern search method for parameter estimation was used to analyze the experimental data of cellulose pyrolysis. The results showed that many parameter sets of the logistic DAEM could fit the data at different heating rates very well for both simulated and experimental processes, and a perfect linear relationship between the logarithm of the frequency factor and the mean value of the activation energy distribution was found. The parameters of the logistic DAEM can be estimated by coupling the optimization method and isoconversional kinetic methods. The results would be helpful for chemical kinetic analysis using DAEM. Copyright © 2018 Elsevier Ltd. All rights reserved.

Tuning the surface morphology of aluminium doped zinc oxide thin films by arrayed nanorods through chemical growth process

NASA Astrophysics Data System (ADS)

Devasia, Sebin; Anila, E. I.

2018-04-01

Here we report the growth and characterization of chemically grown aluminium doped zinc oxide nanorods on seed layers. The seed layers were prepared by chemical spray pyrolysis which acted as the growth centers. The growth duration of nanorods were varied from 3h to 12h in steps of 3h. Further, investigations on their structural, morphological, electrical and optical properties. The SEM images confirmed the hexagonal shaped nanorod arrays grown on the seed layers. Later, the x-ray diffraction measurements revealed the pure zinc oxide phase of the samples. Photoluminescence and photoconductivity studies were carried out to analyze the potential of its optoelectronic properties.

Dye-sensitized solar cells fabricated with black raspberry, black carrot and rosella juice

NASA Astrophysics Data System (ADS)

Tekerek, S.; Kudret, A.; Alver, Ü.

2011-10-01

In this work, dye sensitized solar cells (DSSC's) were constructed from black raspberry ( Rubus Ideaus), black carrot ( Daucuscarota L.) and rosella juice ( Hibiscus Sabdariffa L.). In order to fabricate a DSSC the fluorine-doped tin (IV) oxide (FTO) thin films obtained by using spray pyrolysis technique were used as a substrate. TiO2 films on FTO layers were prepared by doctor-blading technique. Platinum-coated counter electrode and liquid Iodide/Iodine electrolyte solution were used to fabricate DSSC's. The efficiencies of solar cells produced with black carrot, rosella and black raspberry juice were calculated as 0.25%, 0.16% and 0.16% respectively, under a sunny day in Kahramanmaraş-Turkey.

CuCo 2O 4 ORR/OER Bi-functional catalyst: Influence of synthetic approach on performance

DOE PAGES

Serov, Alexey; Andersen, Nalin I.; Roy, Aaron J.; ...

2015-02-07

A series of CuCo 2O 4 catalysts were synthesized by pore forming, sol-gel, spray pyrolysis and sacrificial support methods. Catalysts were characterized by XRD, SEM, XPS and BET techniques. The electrochemical activity for the oxygen reduction and oxygen evolution reactions (ORR and OER) was evaluated in alkaline media by RRDE. Density Functional Theory was used to identify two different types of active sites responsible for ORR/OER activity of CuCo 2O 4 and it was found that CuCo 2O 4 can activate the O-O bond by binding molecular oxygen in bridging positions between Co or Co and Cu atoms. It wasmore » found that the sacrificial support method (SSM) catalyst has the highest performance in both ORR and OER and has the highest content of phase-pure CuCo 2O 4. It was shown that the presence of CuO significantly decreases the activity in oxygen reduction and oxygen evolution reactions. As a result, the half-wave potential (E 1/2) of CuCo 2O 4-SSM was found as 0.8 V, making this material a state-of-the-art, unsupported oxide catalyst.« less

Preparation and Layer-by-Layer Solution Deposition of Cu(In,Ga)O2 Nanoparticles with Conversion to Cu(In,Ga)S2 Films

PubMed Central

Dressick, Walter J.; Soto, Carissa M.; Fontana, Jake; Baker, Colin C.; Myers, Jason D.; Frantz, Jesse A.; Kim, Woohong

2014-01-01

We present a method of Cu(In,Ga)S2 (CIGS) thin film formation via conversion of layer-by-layer (LbL) assembled Cu-In-Ga oxide (CIGO) nanoparticles and polyelectrolytes. CIGO nanoparticles were created via a novel flame-spray pyrolysis method using metal nitrate precursors, subsequently coated with polyallylamine (PAH), and dispersed in aqueous solution. Multilayer films were assembled by alternately dipping quartz, Si, and/or Mo substrates into a solution of either polydopamine (PDA) or polystyrenesulfonate (PSS) and then in the CIGO-PAH dispersion to fabricate films as thick as 1–2 microns. PSS/CIGO-PAH films were found to be inadequate due to weak adhesion to the Si and Mo substrates, excessive particle diffusion during sulfurization, and mechanical softness ill-suited to further processing. PDA/CIGO-PAH films, in contrast, were more mechanically robust and more tolerant of high temperature processing. After LbL deposition, films were oxidized to remove polymer and sulfurized at high temperature under flowing hydrogen sulfide to convert CIGO to CIGS. Complete film conversion from the oxide to the sulfide is confirmed by X-ray diffraction characterization. PMID:24941104

Derivation of hydrous pyrolysis kinetic parameters from open-system pyrolysis

NASA Astrophysics Data System (ADS)

Tseng, Yu-Hsin; Huang, Wuu-Liang

2010-05-01

Kinetic information is essential to predict the temperature, timing or depth of hydrocarbon generation within a hydrocarbon system. The most common experiments for deriving kinetic parameters are mainly by open-system pyrolysis. However, it has been shown that the conditions of open-system pyrolysis are deviant from nature by its low near-ambient pressure and high temperatures. Also, the extrapolation of heating rates in open-system pyrolysis to geological conditions may be questionable. Recent study of Lewan and Ruble shows hydrous-pyrolysis conditions can simulate the natural conditions better and its applications are supported by two case studies with natural thermal-burial histories. Nevertheless, performing hydrous pyrolysis experiment is really tedious and requires large amount of sample, while open-system pyrolysis is rather convenient and efficient. Therefore, the present study aims at the derivation of convincing distributed hydrous pyrolysis Ea with only routine open-system Rock-Eval data. Our results unveil that there is a good correlation between open-system Rock-Eval parameter Tmax and the activation energy (Ea) derived from hydrous pyrolysis. The hydrous pyrolysis single Ea can be predicted from Tmax based on the correlation, while the frequency factor (A0) is estimated based on the linear relationship between single Ea and log A0. Because the Ea distribution is more rational than single Ea, we modify the predicted single hydrous pyrolysis Ea into distributed Ea by shifting the pattern of Ea distribution from open-system pyrolysis until the weight mean Ea distribution equals to the single hydrous pyrolysis Ea. Moreover, it has been shown that the shape of the Ea distribution is very much alike the shape of Tmax curve. Thus, in case of the absence of open-system Ea distribution, we may use the shape of Tmax curve to get the distributed hydrous pyrolysis Ea. The study offers a new approach as a simple method for obtaining distributed hydrous pyrolysis Ea with only routine open-system Rock-Eval data, which will allow for better estimating hydrocarbon generation.

A pyrolysis study for the thermal and kinetic characteristics of an agricultural waste with two different plastic wastes.

PubMed

Çepelioğullar, Özge; Pütün, Ayşe E

2014-10-01

In this study, thermochemical conversion of plastic wastes (PET and PVC) together with an agricultural waste (hazelnut shell) was investigated. In order to determine the thermal and kinetic behaviours, pyrolysis experiments were carried out from room temperature to 800 °C, with a heating rate of 10 °C min(-1) in the presence of a N2 atmosphere in a thermogravimetric analyzer. With the obtained thermogravimetric data, an appropriate temperature was specified for the pyrolysis of biomass-plastic wastes in a fixed-bed reactor. At the second step, pyrolysis experiments were carried out at the same conditions with the thermogravimetric analyzer, except the final temperature which was up to 500 °C in this case. After pyrolysis experiments, pyrolysis yields were calculated and characterization studies for bio-oil were investigated. Experimental results showed that co-pyrolysis has an important role in the determination of the pyrolysis mechanism and the process conditions while designing/implementing a thermochemical conversion method where biomass-plastic materials were preferred as raw materials. © The Author(s) 2014.

Kinetics of scrap tyre pyrolysis under vacuum conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lopez, Gartzen; Aguado, Roberto; Olazar, Martin

2009-10-15

Scrap tyre pyrolysis under vacuum is attractive because it allows easier product condensation and control of composition (gas, liquid and solid). With the aim of determining the effect of vacuum on the pyrolysis kinetics, a study has been carried out in thermobalance. Two data analysis methods have been used in the kinetic study: (i) the treatment of experimental data of weight loss and (ii) the deconvolution of DTG (differential thermogravimetry) curve. The former allows for distinguishing the pyrolysis of the three main components (volatile components, natural rubber and styrene-butadiene rubber) according to three successive steps. The latter method identifies themore » kinetics for the pyrolysis of individual components by means of DTG curve deconvolution. The effect of vacuum in the process is significant. The values of activation energy for the pyrolysis of individual components of easier devolatilization (volatiles and NR) are lower for pyrolysis under vacuum with a reduction of 12 K in the reaction starting temperature. The kinetic constant at 503 K for devolatilization of volatile additives at 0.25 atm is 1.7 times higher than that at 1 atm, and that corresponding to styrene-butadiene rubber at 723 K is 2.8 times higher. Vacuum enhances the volatilization and internal diffusion of products in the pyrolysis process, which contributes to attenuating the secondary reactions of the repolymerization and carbonization of these products on the surface of the char (carbon black). The higher quality of carbon black is interesting for process viability. The large-scale implementation of this process in continuous mode requires a comparison to be made between the economic advantages of using a vacuum and the energy costs, which will be lower when the technologies used for pyrolysis require a lower ratio between reactor volume and scrap tyre flow rate.« less

Kinetics of scrap tyre pyrolysis under vacuum conditions.

PubMed

Lopez, Gartzen; Aguado, Roberto; Olazar, Martín; Arabiourrutia, Miriam; Bilbao, Javier

2009-10-01

Scrap tyre pyrolysis under vacuum is attractive because it allows easier product condensation and control of composition (gas, liquid and solid). With the aim of determining the effect of vacuum on the pyrolysis kinetics, a study has been carried out in thermobalance. Two data analysis methods have been used in the kinetic study: (i) the treatment of experimental data of weight loss and (ii) the deconvolution of DTG (differential thermogravimetry) curve. The former allows for distinguishing the pyrolysis of the three main components (volatile components, natural rubber and styrene-butadiene rubber) according to three successive steps. The latter method identifies the kinetics for the pyrolysis of individual components by means of DTG curve deconvolution. The effect of vacuum in the process is significant. The values of activation energy for the pyrolysis of individual components of easier devolatilization (volatiles and NR) are lower for pyrolysis under vacuum with a reduction of 12K in the reaction starting temperature. The kinetic constant at 503K for devolatilization of volatile additives at 0.25atm is 1.7 times higher than that at 1atm, and that corresponding to styrene-butadiene rubber at 723K is 2.8 times higher. Vacuum enhances the volatilization and internal diffusion of products in the pyrolysis process, which contributes to attenuating the secondary reactions of the repolymerization and carbonization of these products on the surface of the char (carbon black). The higher quality of carbon black is interesting for process viability. The large-scale implementation of this process in continuous mode requires a comparison to be made between the economic advantages of using a vacuum and the energy costs, which will be lower when the technologies used for pyrolysis require a lower ratio between reactor volume and scrap tyre flow rate.

Method for Hot Real-Time Analysis of Pyrolysis Vapors at Pilot Scale

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pomeroy, Marc D

Pyrolysis oils contain more than 400 compounds, up to 60% of which do not re-volatilize for subsequent chemical analysis. Vapor chemical composition is also complicated as additional condensation reactions occur during quenching and collection of the product. Due to the complexity of the pyrolysis oil, and a desire to catalytically upgrade the vapor composition before condensation, online real-time analytical techniques such as Molecular Beam Mass Spectrometry (MBMS) are of great use. However, in order to properly sample hot pyrolysis vapors at the pilot scale, many challenges must be overcome.

Carbon nanoscrolls by pyrolysis of a polymer

NASA Astrophysics Data System (ADS)

Yadav, Prasad; Warule, Sambhaji; Jog, Jyoti; Ogale, Satishchandra

2012-12-01

3D network of carbon nanoscrolls was synthesized starting from pyrolysis of poly(acrylic acid-co-maleic acid) sodium salt. It is a catalyst-free process where pyrolysis of polymer leads to formation of carbon form and sodium carbonate. Upon water soaking of pyrolysis product, the carbon form undergoes self-assembly to form carbon nanoscrolls. The interlayer distance between the walls of carbon nanoscroll was found to be 0.34 nm and the carbon nanoscrolls exhibited a surface area of 188 m2/g as measured by the BET method.

Decaking of coal or oil shale during pyrolysis in the presence of iron oxides

DOEpatents

Khan, M. Rashid

1989-01-01

A method for producing a fuel from the pyrolysis of coal or oil shale in the presence of iron oxide in an inert gas atmosphere. The method includes the steps of pulverizing feed coal or oil shale, pulverizing iron oxide, mixing the pulverized feed and iron oxide, and heating the mixture in a gas atmosphere which is substantially inert to the mixture so as to form a product fuel, which may be gaseous, liquid and/or solid. The method of the invention reduces the swelling of coals, such as bituminous coal and the like, which are otherwise known to swell during pyrolysis.

CFD Modeling of a Laser-Induced Ethane Pyrolysis in a Wall-less Reactor

NASA Astrophysics Data System (ADS)

Stadnichenko, Olga; Snytnikov, Valeriy; Yang, Junfeng; Matar, Omar

2014-11-01

Ethylene, as the most important feedstock, is widely used in chemical industry to produce various rubbers, plastics and synthetics. A recent study found the IR-laser irradiation induced ethane pyrolysis yields 25% higher ethylene production rates compared to the conventional steam cracking method. Laser induced pyrolysis is initiated by the generation of radicals upon heating of the ethane, then, followed by ethane/ethylene autocatalytic reaction in which ethane is converted into ethylene and other light hydrocarbons. This procedure is governed by micro-mixing of reactants and the feedstock residence time in reactor. Under mild turbulent conditions, the turbulence enhances the micro-mixing process and allows a high yield of ethylene. On the other hand, the high flow rate only allows a short residence time in the reactor which causes incomplete pyrolysis. This work attempts to investigate the interaction between turbulence and ethane pyrolysis process using large eddy simulation method. The modelling results could be applied to optimize the reactor design and operating conditions. Skolkovo Foundation through the UNIHEAT Project.

Hybrid-renewable processes for biofuels production: concentrated solar pyrolysis of biomass residues

DOE Office of Scientific and Technical Information (OSTI.GOV)

George, Anthe; Geier, Manfred; Dedrick, Daniel E.

2014-10-01

The viability of thermochemically-derived biofuels can be greatly enhanced by reducing the process parasitic energy loads. Integrating renewable power into biofuels production is one method by which these efficiency drains can be eliminated. There are a variety of such potentially viable "hybrid-renewable" approaches; one is to integrate concentrated solar power (CSP) to power biomass-to-liquid fuels (BTL) processes. Barriers to CSP integration into BTL processes are predominantly the lack of fundamental kinetic and mass transport data to enable appropriate systems analysis and reactor design. A novel design for the reactor has been created that can allow biomass particles to be suspendedmore » in a flow gas, and be irradiated with a simulated solar flux. Pyrolysis conditions were investigated and a comparison between solar and non-solar biomass pyrolysis was conducted in terms of product distributions and pyrolysis oil quality. A novel method was developed to analyse pyrolysis products, and investigate their stability.« less

Characterization of typical heavy metals in pyrolysis MSWI fly ash.

PubMed

Xu, Tengtun; Wang, Li'ao; Zeng, Yunmin; Zhao, Xue; Wang, Lei; Zhan, Xinyuan; Li, Tong; Yang, Lu

2018-06-07

Thermal treatment methods are used extensively in the process of municipal solid waste incineration fly ash. However, the characterization of heavy metals during this process should be understood more clearly in order to control secondary pollution. In this paper, the content, speciation and leaching toxicity of mercury (Hg), plumbum (Pb), cadmium (Cd) and zinc (Zn) in fly ash treated under different temperatures and time were firstly analysed as pre-tests. Later, pilot-scale pyrolysis equipment was used to explore the concentration and speciation changes in the heavy metals of fly ash. Finally, the phase constitution and microstructure changes in fly ash were compared before and after pyrolysis using X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. The results showed that (a) The appropriate processing temperature was between 400°C and 450°C, and the processing time should be 1 h. (b) The stability of heavy metals in fly ash increased after pyrolysis. (c) XRD and SEM results indicated that phase constitution changed a little, but the microstructure varied to a porous structure similar to that of a coral reef after pyrolysis. These results suggest that pyrolysis could be an effective method in controlling heavy metal pollution in fly ash.

Discernment of synergism in pyrolysis of biomass blends using thermogravimetric analysis.

PubMed

Mallick, Debarshi; Poddar, Maneesh Kumar; Mahanta, Pinakeswar; Moholkar, Vijayanand S

2018-08-01

This study reports pyrolysis kinetics of biomass blends using isoconversional methods, viz. Friedman, FWO and KAS. Blends of three biomasses, viz. saw dust, bamboo dust and rice husk, were used. Extractives and volatiles in biomass and minerals in ash had marked influence on enhancement of reaction kinetics during co-pyrolysis, as indicated by reduction in activation energy and increase in decomposition intensity. Pyrolysis kinetics of saw dust and rice husk accelerated (positive synergy), while that of bamboo dust decelerated after blending (negative synergy). Predominant reaction mechanism of all biomass blends was 3-D diffusion in lower conversion range (α ≤ 0.5), while for α ≥ 0.5 pyrolysis followed random nucleation (or nucleation and growth mechanism). Higher reaction order for pyrolysis of blends of rice husk with saw dust and bamboo dust was attributed to catalytic effect of minerals in ash. Positive ΔH and ΔG was obtained for pyrolysis of all biomass blends. Copyright © 2018 Elsevier Ltd. All rights reserved.

Formate-assisted pyrolysis

DOEpatents

DeSisto, William Joseph; Wheeler, Marshall Clayton; van Heiningen, Adriaan R. P.

2015-03-17

The present invention provides, among other thing, methods for creating significantly deoxygenated bio-oils form biomass including the steps of providing a feedstock, associating the feedstock with an alkali formate to form a treated feedstock, dewatering the treated feedstock, heating the dewatered treated feedstock to form a vapor product, and condensing the vapor product to form a pyrolysis oil, wherein the pyrolysis oil contains less than 30% oxygen by weight.

Shape matters: Cr(VI) removal using iron nanoparticle impregnated 1-D vs 2-D carbon nanohybrids prepared by ultrasonic spray pyrolysis

NASA Astrophysics Data System (ADS)

Masud, Arvid; Cui, Yanbin; Atkinson, John D.; Aich, Nirupam

2018-03-01

Iron nanoparticles (Fe NPs) are used for treating water contaminated with metals or organic compounds. One-dimensional (1-D) carbon nanotubes (CNTs) and two-dimensional (2-D) graphenes act as useful nanocarbon (NC) supports for Fe NPs by resisting aggregation and enhancing adsorption and redox activity. However, no study showed how shape difference between tubular CNT and planar graphene structures dictates the physicochemical properties and pollutant removal potential of their iron-based nanohybrids. In this work, ultrasonic spray pyrolysis was used to continuously prepare Fe-CNT and Fe-rGO nanohybrids. Both NC shape and Fe/NC ratio influenced Fe NP size, loading, and oxidation states. High Fe content (precursor Fe/NC mass ratio = 2) resulted Fe NPs with diameters of 30.97 ± 7.00 and 24.11 ± 4.42 nm for Fe-CNT and Fe-rGO, respectively; however, low Fe content (Fe/NC = 0.2) provided more uniformly dispersed Fe NPs of 15.65 ± 3.06 and 9.67 ± 1.49 nm, respectively, while unsupported Fe NPs were 285.71 ± 132.42 nm. The USP-derived nanohybrids, for the first time, were used for removal of pollutant, i.e., chromium (Cr(VI)) from aqueous media. Both CNT and rGO provided synergistic effects to significantly enhance Fe NPs' ability to remove Cr(VI); the effect was more pronounced in Fe-rGO than Fe-CNT and also for low Fe content in both cases. Fe-rGO with low Fe/NC ratio and smallest Fe NPs provided the highest Cr(VI) removal capacity (25 mg/g), which was a multifold improvement over bare Fe NPs and other synthesized nanohybrids (range 7-14 mg/g). Overall, 2-D rGO improved contaminant removal capacity of the nanohybrids more than 1-D CNT indicating towards shape effect of NC supports. [Figure not available: see fulltext.

Kinetics and evolved gas analysis for pyrolysis of food processing wastes using TGA/MS/FT-IR.

PubMed

Özsin, Gamzenur; Pütün, Ayşe Eren

2017-06-01

The objective of this study was to identify the pyrolysis of different bio-waste produced by food processing industry in a comprehensible manner. For this purpose, pyrolysis behaviors of chestnut shells (CNS), cherry stones (CS) and grape seeds (GS) were investigated by thermogravimetric analysis (TGA) combined with a Fourier-transform infrared (FT-IR) spectrometer and a mass spectrometer (MS). In order to make available theoretical groundwork for biomass pyrolysis, activation energies were calculated with the help of four different model-free kinetic methods. The results are attributed to the complex reaction schemes which imply parallel, competitive and complex reactions during pyrolysis. During pyrolysis, the evolution of volatiles was also characterized by FT-IR and MS. The main evolved gases were determined as H 2 O, CO 2 and hydrocarbons such as CH 4 and temperature dependent profiles of the species were obtained. Copyright © 2017 Elsevier Ltd. All rights reserved.

Recent progress on biomass co-pyrolysis conversion into high-quality bio-oil.

PubMed

Hassan, H; Lim, J K; Hameed, B H

2016-12-01

Co-pyrolysis of biomass with abundantly available materials could be an economical method for production of bio-fuels. However, elimination of oxygenated compounds poses a considerable challenge. Catalytic co-pyrolysis is another potential technique for upgrading bio-oils for application as liquid fuels in standard engines. This technique promotes the production of high-quality bio-oil through acid catalyzed reduction of oxygenated compounds and mutagenic polyaromatic hydrocarbons. This work aims to review and summarize research progress on co-pyrolysis and catalytic co-pyrolysis, as well as their benefits on enhancement of bio-oils derived from biomass. This review focuses on the potential of plastic wastes and coal materials as co-feed in co-pyrolysis to produce valuable liquid fuel. This paper also proposes future directions for using this technique to obtain high yields of bio-oils. Copyright © 2016 Elsevier Ltd. All rights reserved.

Site-Specific Pyrolysis Induced Cleavage at Aspartic Acid Residue in Peptides and Proteins

PubMed Central

Zhang, Shaofeng; Basile, Franco

2011-01-01

A simple and site-specific non-enzymatic method based on pyrolysis has been developed to cleave peptides and proteins. Pyrolytic cleavage was found to be specific and rapid as it induced a cleavage at the C-terminal side of aspartic acid in the temperature range of 220–250 °C in 10 seconds. Electrospray Ionization (ESI) mass spectrometry (MS) and tandem-MS (MS/MS) were used to characterize and identify pyrolysis cleavage products, confirming that sequence information is conserved after the pyrolysis process in both peptides and protein tested. This suggests that pyrolysis-induced cleavage at aspartyl residues can be used as a rapid protein digestion procedure for the generation of sequence specific protein biomarkers. PMID:17388620

Nanocomposites with embedded structures for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Yang, Zichao

Lithium-ion batteries (LIBs) have been widely employed in portable electronics and are rapidly expanding into emerging markets such as hybrid and electric vehicles and potentially electric grid storage. These new opportunities create new challenges for LIBs and further improvement of specific energy, cycling performance and rate capability are required. A major strategy in performance enhancement for the electrode materials involves the creation of carbon composites to provide mechanical buffering of active material and to improve electrical conductivity. In the current work, a platform is developed for creating functional hybrid materials by copolymerization of organic molecules and inorganic compounds followed by thermal pyrolysis, and the approach yields nanostructured composites in which nanoparticles are uniformly embedded in a porous, partially graphitic carbon matrix. Depending upon the chemistry of the starting materials, nanocomposites with embedded structures created using the approach are attractive as anode or cathode materials for next-generation rechargeable lithium battery systems. The platform is very versatile and through ex situ conversion or utilization of multiple precursors, can be applied to various classes of materials including metal oxides (single or mixed), metals, metal sulfides, alloys, metalloids, phosphates, etc. The approach also lends itself to the development of scalable processes for production of nanostructured battery materials. Mechanistic analysis was performed and reveals that the performance enhancement of the embedded nanocomposite configuration is mainly brought about by the mechanical buffering effect offered by the carbon matrix. The active material loading was shown to be an important factor in the design of the composites as electrode materials. In addition to the polymerization-based approach, other in situ methods such as one based on spray pyrolysis are also explored and demonstrate the versatility of the in situ synthesis concept.

Decaking of coal or oil shale during pyrolysis in the presence of iron oxides

DOEpatents

Rashid Khan, M.

1988-05-05

A method for producing a fuel from the pyrolysis of coal or oil shale in the presence of iron oxide in an inert gas atmosphere is described. The method includes the steps of pulverizing feed coal or oil shale, pulverizing iron oxide, mixing the pulverized feed and iron oxide, and heating the mixture in a gas atmosphere which is substantially inert to the mixture so as to form a product fuel, which may be gaseous, liquid and/or solid. The method of the invention reduces the swelling of coals, such as bituminous coal and the like, which are otherwise known to swell during pyrolysis. 4 figs., 8 tabs.

Method for preventing plugging in the pyrolysis of agglomerative coals

DOEpatents

Green, Norman W.

1979-01-23

To prevent plugging in a pyrolysis operation where an agglomerative coal in a nondeleteriously reactive carrier gas is injected as a turbulent jet from an opening into an elongate pyrolysis reactor, the coal is comminuted to a size where the particles under operating conditions will detackify prior to contact with internal reactor surfaces while a secondary flow of fluid is introduced along the peripheral inner surface of the reactor to prevent backflow of the coal particles. The pyrolysis operation is depicted by two equations which enable preselection of conditions which insure prevention of reactor plugging.

Comparative assessment of municipal sewage sludge incineration, gasification and pyrolysis for a sustainable sludge-to-energy management in Greece

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samolada, M.C.; Zabaniotou, A.A., E-mail: azampani@auth.gr

2014-02-15

Highlights: • The high output of MSS highlights the need for alternative routes of valorization. • Evaluation of 3 sludge-to-energy valorisation methods through SWOT analysis. • Pyrolysis is an energy and material recovery process resulting to ‘zero waste’. • Identification of challenges and barriers for MSS pyrolysis in Greece was investigated. • Adopters of pyrolysis systems face the challenge of finding new product markets. - Abstract: For a sustainable municipal sewage sludge management, not only the available technology, but also other parameters, such as policy regulations and socio-economic issues should be taken in account. In this study, the current statusmore » of both European and Greek Legislation on waste management, with a special insight in municipal sewage sludge, is presented. A SWOT analysis was further developed for comparison of pyrolysis with incineration and gasification and results are presented. Pyrolysis seems to be the optimal thermochemical treatment option compared to incineration and gasification. Sewage sludge pyrolysis is favorable for energy savings, material recovery and high added materials production, providing a ‘zero waste’ solution. Finally, identification of challenges and barriers for sewage sludge pyrolysis deployment in Greece was investigated.« less

Magneto-transport and magneto-optical studies on SnO2 transparent semiconducting thin films alloyed with Mn over a wide range of concentration

NASA Astrophysics Data System (ADS)

Bagheri Mohagheghi, M. M.; Tabatabai Yazdi, Sh.; Mousavi, M.

2018-03-01

In this work, Mn-alloyed tin oxide transparent thin films with different Mn concentrations up to 60 at% were prepared via the spray pyrolysis method, and their structural, magneto-optical, and magneto-transport properties were studied. The results show that all the deposited films are polycrystalline with the tetragonal rutile structure. The unit cell volume of Sn1- x Mn x O2 films was found to be minimum at the Mn concentration of x = 0.15 indicating to two different mechanisms for Mn addition in the crystal lattice of tin oxide. For the films with Mn concentrations less than 15%, substitutional doping is the working mechanism, while for more Mn concentrations, interstitial one is predominant. A critical Mn concentration about that observed for the structural properties of the films (i.e., x = 0.15) was revealed for their magnetoresistance and magneto-optical properties, as well. This suggests a correlation between the structural and magnetic behaviors of the deposited SnO2:Mn films.

The decoration of Nb-doped TiO2 microspheres by reduced graphene oxide for enhanced CO gas sensing

NASA Astrophysics Data System (ADS)

Liang, Feng; Chen, Shimin; Xie, Wei; Zou, Changwei

2018-03-01

Reduced graphene oxide (rGO) was used to improve the CO sensing properties of Nb-doped TiO2 (TiO2:Nb) microspheres by an improved ultrasonic spray pyrolysis deposition method. The responses of the sensor dramatically increased as the CO gas concentration increased from 100 to 1000 ppm, which indicated that rGO/TiO2:Nb-based sensor had a wide detection range for CO gas. Moreover, the conductivity of sensor based on the rGO/TiO2:Nb would be greatly improved than that of sensors without decoration by rGO. The enhanced gas sensing performance of the rGO/TiO2:Nb can be attributed to two reasons. Firstly, rGO could facilitate charge transport from TiO2 to graphene which provided a preferential pathway for the charge currents. Secondly, the decorated TiO2 by rGO could provide more active sites such as oxygen vacancy (VO) which could capture electrons from the conductance band and form a space-charge region.

Exciting transition metal doped dilute magnetic thin films: MgO:Er and ZnO:Er

NASA Astrophysics Data System (ADS)

Ćakıcı, T.; Sarıtaş, S.; Muǧlu, G. Merhan; Yıldırım, M.

2017-02-01

Erbium doped MgO and doped ZnO thin films have reasonably important properties applications in spintronic devices. These films were synthesized on glass substrates by Chemical Spray Pyrolysis (CSP) method. In the literature there has been almost no report on preparation of MgO:Er dilute magnetic thin films by means of CSP. Because doped thin films show different magnetic behaviors, depending upon the type of magnetic material ions, concentration of them, synthesis route and experimental conditions, synthesized MgO:Er and ZnO:Er films were compared to thin film properties. Optical analyses of the synthesized thin films were examined spectral absorption and transmittance measurements by UV-Vis double beam spectrophotometer technique. Structural analysis of the thin films was examined by using XRD, Raman Analysis, FE-SEM, EDX and AFM techniques. Also, magnetic properties of the MgO:Er and ZnO:Er films were investigated by vibrating sample magnetometer (VSM) which show that diamagnetic behavior of the MgO:Er thin film and ferromagnetic (FM) behavior of the ZnO:Er film were is formed.

Effect of Sulfur Concentration on the Morphology of Carbon Nanofibers Produced from a Botanical Hydrocarbon

NASA Astrophysics Data System (ADS)

Ghosh, Pradip; Soga, Tetsuo; Ghosh, Kaushik; Jimbo, Takashi; Katoh, Ryoji; Sumiyama, Kenji; Ando, Yoshinori

2008-07-01

Carbon nanofibers (CNF) with diameters of 20 130 nm with different morphologies were obtained from a botanical hydrocarbon: Turpentine oil, using ferrocene as catalyst source and sulfur as a promoter by simple spray pyrolysis method at 1,000 °C. The influence of sulfur concentration on the morphology of the carbon nanofibers was investigated. SEM, TEM, Raman, TGA/DTA, and BET surface area were employed to characterize the as-prepared samples. TEM analysis confirms that as-prepared CNFs have a very sharp tip, bamboo shape, open end, hemispherical cap, pipe like morphology, and metal particle trapped inside the wide hollow core. It is observed that sulfur plays an important role to promote or inhibit the CNF growth. Addition of sulfur to the solution of ferrocene and turpentine oil mixture was found to be very effective in promoting the growth of CNF. Without addition of sulfur, carbonaceous product was very less and mainly soot was formed. At high concentration of sulfur inhibit the growth of CNFs. Hence the yield of CNFs was optimized for a given sulfur concentration.

Fabrication and Testing of Low Cost 2D Carbon-Carbon Nozzle Extensions at NASA/MSFC

NASA Technical Reports Server (NTRS)

Greene, Sandra Elam; Shigley, John K.; George, Russ; Roberts, Robert

2015-01-01

Subscale liquid engine tests were conducted at NASA/MSFC using a 1.2 Klbf engine with liquid oxygen (LOX) and gaseous hydrogen. Testing was performed for main-stage durations ranging from 10 to 160 seconds at a chamber pressure of 550 psia and a mixture ratio of 5.7. Operating the engine in this manner demonstrated a new and affordable test capability for evaluating subscale nozzles by exposing them to long duration tests. A series of 2D C-C nozzle extensions were manufactured, oxidation protection applied and then tested on a liquid engine test facility at NASA/MSFC. The C-C nozzle extensions had oxidation protection applied using three very distinct methods with a wide range of costs and process times: SiC via Polymer Impregnation & Pyrolysis (PIP), Air Plasma Spray (APS) and Melt Infiltration. The tested extensions were about 6" long with an exit plane ID of about 6.6". The test results, material properties and performance of the 2D C-C extensions and attachment features will be discussed.

Structural and optical properties of nanocrystalline ZnS and ZnS:Al films

NASA Astrophysics Data System (ADS)

Hurma, T.

2018-06-01

ZnS and ZnS:Al films have been deposited by ultrasonic spray pyrolysis (USP) method. Three different atomic ratios of aluminium were used as the dopant element. The effects of aluminum incorporation on structural and optical properties of the ZnS films have been investigated. The XRD analysis showed that the cubic structure of the ZnS was not much affected by Al doping. The crystal size of the films decreased, as the Al ratio increased. Al incorporation caused an increase in the intensity of ZnS films' peaks observed in Raman spectra and nearly symmetrical peaks were observed. Al doping caused a small decrease in optical band gap of the ZnS film. The coating of ZnS:Al films on the surface was quite good and there were not any deformation in their crystallization levels. Reflectance values of films are about 5% in the visible region but a little decrease is seen with aluminum doping. We can say that Al doping tends to improve the optical properties of the ZnS:Al films when compared with the undoped ZnS.

Laser pyrolysis fabrication of ferromagnetic gamma'-Fe4N and FeC nanoparticles

NASA Technical Reports Server (NTRS)

Grimes, C. A.; Qian, D.; Dickey, E. C.; Allen, J. L.; Eklund, P. C.

2000-01-01

Using the laser pyrolysis method, single phase gamma'-Fe4N nanoparticles were prepared by a two step method involving preparation of nanoscale iron oxide and a subsequent gas-solid nitridation reaction. Single phase Fe3C and Fe7C3 could be prepared by laser pyrolysis from Fe(CO)5 and 3C2H4 directly. Characterization techniques such as XRD, TEM and vibrating sample magnetometer were used to measure phase structure, particle size and magnetic properties of these nanoscale nitride and carbide particles. c2000 American Journal of Physics.

Selective production of chemicals from biomass pyrolysis over metal chlorides supported on zeolite.

PubMed

Leng, Shuai; Wang, Xinde; Cai, Qiuxia; Ma, Fengyun; Liu, Yue'e; Wang, Jianguo

2013-12-01

Direct biomass conversion into chemicals remains a great challenge because of the complexity of the compounds; hence, this process has attracted less attention than conversion into fuel. In this study, we propose a simple one-step method for converting bagasse into furfural (FF) and acetic acid (AC). In this method, bagasse pyrolysis over ZnCl2/HZSM-5 achieved a high FF and AC yield (58.10%) and a 1.01 FF/AC ratio, but a very low yield of medium-boiling point components. However, bagasse pyrolysis using HZSM-5 alone or ZnCl2 alone still remained large amounts of medium-boiling point components or high-boiling point components. The synergistic effect of HZSM-5 and ZnCl2, which combines pyrolysis, zeolite cracking, and Lewis acid-selective catalysis results in highly efficient bagasse conversion into FF and AC. Therefore, our study provides a novel, simple method for directly converting biomass into high-yield useful chemical. Copyright © 2013 Elsevier Ltd. All rights reserved.

Liquid Fertilizer Spraying Performance Using A Knapsack Power Sprayer On Soybean Field

NASA Astrophysics Data System (ADS)

Gatot, P.; Anang, R.

2018-05-01

An effort for increasing soybean production can be conducted by applying liquid fertilizer on soybean cultivation field. The objective of this research was to determine liquid fertilizer spraying performance using knapsack power sprayer TASCO TF-900 on a soybean cultivation field. Performances test were conducted in the Laboratory of Spraying Test and on a soybean cultivation field to determine (1) effective spraying width, (2) droplets diameter, (3) droplets density, (4) effective spraying discharge rate, and (5) effective field capacity of spraying. The research was conducted using 2 methods: (1) one-nozzle spraying, and (2) four- nozzles spraying. Results of the research showed that at a constant pressure of 900 kPa effective spraying width using one-nozzle spraying and four-nozzles spraying were 0.62 m and 1.10 m. A bigger effective spraying width was resulted in a bigger average effective spraying discharge rate and average effective spraying field capacity of 4.52 l/min and 83.92 m2/min on forward walking speed range of 0.94 m/s up to 1.77 m/s. On the contrary, bigger effective spraying width was result in bigger droplets diameter of 502.73 μm and a smaller droplets density of 98.39 droplets/cm2, whereas smaller effective spraying width was resulted in a smaller droplets diameter of 367.09 μm and a bigger droplets density of 350.53 droplets/cm2. One-nozzle spraying method produced a better spraying quality than four-nozzles spraying method, although four-nozzles spraying was resulted in a bigger effective field capacity of spraying.

In situ upgrading of whole biomass to biofuel precursors with low average molecular weight and acidity by the use of zeolite mixture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ben, Haoxi; Huang, Fang; Li, Liwei

2015-09-09

The pyrolysis of whole biomass—pine wood and bark—with mordenite (M), beta (β) and Y zeolites has been examined at 600°C. The GPC results indicated that the pyrolysis oils upgraded by Y and β zeolites have a very low average molecular weight range (70–170 g mol –1). Several NMR methods have been employed to characterize the whole portion of pyrolysis products. After the use of these two zeolites (Y and β), the two main products from the pyrolysis of cellulose—levoglucosan and HMF—were eliminated; this indicates a significant deoxygenation process. When a mixture of zeolites (Y and M) was used, the upgradedmore » pyrolysis oil exhibited advantages provided by both zeolites; this pyrolysis oil represents a biofuel precursor that has a very low average molecular weight and a relatively low acidity. Finally, this study opens up a new way to upgrade pyrolysis oils by employing mixtures of different functional zeolites to produce biofuel/biochemical precursors from whole biomass.« less

Pyrolysis and reutilization of plant residues after phytoremediation of heavy metals contaminated sediments: For heavy metals stabilization and dye adsorption.

PubMed

Gong, Xiaomin; Huang, Danlian; Liu, Yunguo; Zeng, Guangming; Wang, Rongzhong; Wei, Jingjing; Huang, Chao; Xu, Piao; Wan, Jia; Zhang, Chen

2018-04-01

This study aimed to investigate the effect of pyrolysis on the stabilization of heavy metals in plant residues obtained after phytoremediation. Ramie residues, being collected after phytoremediation of metal contaminated sediments, were pyrolyzed at different temperatures (300-700 °C). Results indicated that pyrolysis was effective in the stabilization of Cd, Cr, Zn, Cu, and Pb in ramie residues by converting the acid-soluble fraction of metals into residual form and decreasing the TCLP-leachable metal contents. Meanwhile, the reutilization potential of using the pyrolysis products generated from ramie residues obtained after phytoremediation as sorbents was investigated. Adsorption experiments results revealed that the pyrolysis products presented excellent ability to adsorb methylene blue (MB) with a maximum adsorption capacity of 259.27 mg/g. This study demonstrated that pyrolysis could be used as an efficient alternative method for stabilizing heavy metals in plant residues obtained after phytoremediation, and their pyrolysis products could be reutilized for dye adsorption. Copyright © 2018 Elsevier Ltd. All rights reserved.

Biotechnological Perspectives of Pyrolysis Oil for a Bio-Based Economy.

PubMed

Arnold, Stefanie; Moss, Karin; Henkel, Marius; Hausmann, Rudolf

2017-10-01

Lignocellulosic biomass is an important feedstock for a potential future bio-based economy. Owing to its compact structure, suitable decomposition technologies will be necessary to make it accessible for biotechnological conversion. While chemical and enzymatic hydrolysis are currently established methods, a promising alternative is provided by fast pyrolysis. The main resulting product thereof, referred to as pyrolysis oil, is an energy-rich and easily transportable liquid. Many of the identified constituents of pyrolysis oil, however, have previously been reported to display adverse effects on microbial growth. In this Opinion we discuss relevant biological, biotechnological, and technological challenges that need to be addressed to establish pyrolysis oil as a reliable microbial feedstock for a bio-based economy of the future. Copyright © 2017 Elsevier Ltd. All rights reserved.

Design and fabrication of a fixed-bed batch type pyrolysis reactor for pilot scale pyrolytic oil production in Bangladesh

NASA Astrophysics Data System (ADS)

Aziz, Mohammad Abdul; Al-khulaidi, Rami Ali; Rashid, MM; Islam, M. R.; Rashid, MAN

2017-03-01

In this research, a development and performance test of a fixed-bed batch type pyrolysis reactor for pilot scale pyrolysis oil production was successfully completed. The characteristics of the pyrolysis oil were compared to other experimental results. A solid horizontal condenser, a burner for furnace heating and a reactor shield were designed. Due to the pilot scale pyrolytic oil production encountered numerous problems during the plant’s operation. This fixed-bed batch type pyrolysis reactor method will demonstrate the energy saving concept of solid waste tire by creating energy stability. From this experiment, product yields (wt. %) for liquid or pyrolytic oil were 49%, char 38.3 % and pyrolytic gas 12.7% with an operation running time of 185 minutes.

Preparation of pyrolysis reference samples: evaluation of a standard method using a tube furnace.

PubMed

Sandercock, P Mark L

2012-05-01

A new, simple method for the reproducible creation of pyrolysis products from different materials that may be found at a fire scene is described. A temperature programmable steady-state tube furnace was used to generate pyrolysis products from different substrates, including softwoods, paper, vinyl sheet flooring, and carpet. The temperature profile of the tube furnace was characterized, and the suitability of the method to reproducibly create pyrolysates similar to those found in real fire debris was assessed. The use of this method to create proficiency tests to realistically test an examiner's ability to interpret complex gas chromatograph-mass spectrometric fire debris data, and to create a library of pyrolsates generated from materials commonly found at a fire scene, is demonstrated. © 2011 American Academy of Forensic Sciences.

Using BPCA and pyrolysis-GC/MS patterns as a measure of charring intensity

NASA Astrophysics Data System (ADS)

Kaal, Joeri; Schneider, Maximilian P. W.; Schmidt, Michael W. I.

2010-05-01

Many questions remain on the molecular properties of Black C (organic fire residues such as charcoal and soot). Here we compare parameters from two methods that have recently shown to be related to the degree of thermal modification ("charring intensity") of charcoal-Black C: i) the proportion of mellitic acid (B6CA) among benzenepolycarboxylic acids in the BPCA method [1,2,3] and ii) the relative proportions and degree of alkylation of pyrolysis products from Black C in pyrolysis-GC/MS [4]. For that purpose we used laboratory chars from rice straw (grass) and chestnut wood (wood) produced at 200-1000 °C under N2 flow. The chars obtained at 450 °C are reference materials of the Black Carbon Ring Trial [5]. Positive correlations between the charring temperature and BPCA and pyrolysis patterns confirm that these methods can be used to study the degree of thermal impact of charred remains. Pyrolysis-GC/MS allowed us to track the thermal degradation of the major biocomponents lignin, polysaccharides, tannin, aliphatic chain lipids, triterpenoids, chlorophyll and proteins, mostly between 250 and 450 °C. The proportions of the pyrolysis products of Black C (benzene, toluene, benzonitrile, PAHs, etc.) and also the ratios that reflect the abundance of aliphatic cross-linkages between aromatic moieties (benzene/toluene, naphthalene/alkylnaphthalenes, benzofuran/alkylbenzofurans), increase with charring intensity. Nonetheless, chars obtained at T > 600 °C (especially for wood) gave low quality pyrograms and poor reproducibility because of high thermal stability. The relative contributions of B6CA, one of the molecular markers used for the BPCA method, are indicative for the degree of condensation of the chars. The BPCA approach showed a clear increase in the relative contribution of B6CA from ca. 5 % at 200 °C to ca. 95 % at 1000 °C, confirming the ability of this parameter to assess charring intensity. The relative contribution of B6CA remains almost constant at ca. 30 % between 250 and 450 °C. Thus, with regard to estimating the charring intensity of Black C, the BPCA method is more suitable for high T chars (> 450 °C) while pyrolysis-GC/MS seems more appropriate in the lower T range (< 500 °C). This is not surprising as larger clusters of polyaromatic domains (high T) can be assessed by the BPCA method but are resistant against pyrolysis. On the other hand, smaller clusters and non-polycondensed portions of Black C (low T) are amenable to pyrolysis-GC/MS but escape the analytical window of the BPCA method. The two methods may therefore be considered complementary, with BPCA giving reliable quantitative data on Black C content and charring degree of high T chars while pyrolysis-GC/MS is quantitatively weak but provides highly detailed information on the molecular properties of especially lower T chars. References [1] Brodowski, S., Rodionov, A., Haumeier L., Glaser, B., Amelung, W. (2005) Org. Geochem. 36, 1299-1310. [2] Glaser, B., Haumeier, L., Guggenberger, G., Zech, W. (1998) Org. Geochem. 29, 811-819. [3] Schneider, M.P.W., Hilf, M., Vogt, U.F., Schmidt, M.W.I., Org. Geochem. (submitted) [4] Kaal, J., Rumpel, C. (2009) Org. Geochem. 40, 1179-1187. [5] Hammes, K., Schmidt, M.W.I., Smernik, R.J. et al. (2007) Global Biogeochemical Cycles 21, 1-18.

Heterodoped nanotubes: theory, synthesis, and characterization of phosphorus-nitrogen doped multiwalled carbon nanotubes.

PubMed

Cruz-Silva, Eduardo; Cullen, David A; Gu, Lin; Romo-Herrera, Jose Manuel; Muñoz-Sandoval, Emilio; López-Urías, Florentino; Sumpter, Bobby G; Meunier, Vincent; Charlier, Jean-Christophe; Smith, David J; Terrones, Humberto; Terrones, Mauricio

2008-03-01

Arrays of multiwalled carbon nanotubes doped with phosphorus (P) and nitrogen (N) are synthesized using a solution of ferrocene, triphenyl-phosphine, and benzylamine in conjunction with spray pyrolysis. We demonstrate that iron phosphide (Fe(3)P) nanoparticles act as catalysts during nanotube growth, leading to the formation of novel PN-doped multiwalled carbon nanotubes. The samples were examined by high resolution electron microscopy and microanalysis techniques, and their chemical stability was explored by means of thermogravimetric analysis in the presence of oxygen. The PN-doped structures reveal important morphology and chemical changes when compared to N-doped nanotubes. These types of heterodoped nanotubes are predicted to offer many new opportunities in the fabrication of fast-response chemical sensors.

Structural, morphological and optical studies of F doped SnO2 thin films

NASA Astrophysics Data System (ADS)

Chandel, Tarun; Thakur, Vikas; Dwivedi, Shailendra Kumar; Zaman, M. Burhanuz; Rajaram, Poolla

2018-05-01

Highly conducting and transparent FTO (flourine doped tin Oxide) thin films were grown on the glass substrates using a low cost spray pyrolysis technique. The films were characterized for their structural, morphological and optical studies using XRD, SEM and UV-Vis spectroscopy. XRD studies show that the FTO films crystallize in Tetragonal cassiterite structure. Morphological analysis using SEM show that the films are uniformly covered with spherical grains albeit high in surface roughness. The average optical transmission greater than 80% in the visible region along with the appearance of interference fringes in the transmission curves confirms the high quality of the films. Electrical studies show that the films exhibit sheet resistance below 10 Ω ϒ-1.

Pyrolysis-combustion 14C dating of soil organic matter

USGS Publications Warehouse

Wang, Hongfang; Hackley, Keith C.; Panno, S.V.; Coleman, D.D.; Liu, J.C.-L.; Brown, J.

2003-01-01

Radiocarbon (14C) dating of total soil organic matter (SOM) often yields results inconsistent with the stratigraphic sequence. The onerous chemical extractions for SOM fractions do not always produce satisfactory 14C dates. In an effort to develop an alternative method, the pyrolysis-combustion technique was investigated to partition SOM into pyrolysis volatile (Py-V) and pyrolysis residue (Py-R) fractions. The Py-V fractions obtained from a thick glacigenic loess succession in Illinois yielded 14C dates much younger but more reasonable than the counterpart Py-R fractions for the soil residence time. Carbon isotopic composition (??13C) was heavier in the Py-V fractions, suggesting a greater abundance of carbohydrate- and protein-related constituents, and ??13C was lighter in the Py-R fractions, suggesting more lignin- and lipid-related constituents. The combination of 14C dates and ??13C values indicates that the Py-V fractions are less biodegradation resistant and the Py-R fractions are more biodegradation resistant. The pyrolysis-combustion method provides a less cumbersome approach for 14C dating of SOM fractions. With further study, this method may become a useful tool for analyzing unlithified terrestrial sediments when macrofossils are absent. ?? 2003 University of Washington. Published by Elsevier Inc. All rights reserved.

The effect of the solution flow rate on the properties of zinc oxide (ZnO) thin films deposited by ultrasonic spray

NASA Astrophysics Data System (ADS)

Attaf, A.; Benkhetta, Y.; Saidi, H.; Bouhdjar, A.; Bendjedidi, H.; Nouadji, M.; Lehraki, N.

2015-03-01

In this work, we used a system based on ultrasonic spray pyrolysis technique. By witch, we have deposited thin films of zinc oxide (ZnO) with the variation of solution flow rate from 50 ml / h to 150 ml / h, and set other parameters such as the concentration of the solution, the deposition time, substrate temperature and the nozzel -substrate distance. In order to study the influence of the solution flow rate on the properties of the films produced, we have several characterization techniques such as X-ray diffraction to determine the films structure, the scanning electron microscopy SEM for the morphology of the surfaces, EDS spectroscopy for the chemical composition, UV-Visible-Nir spectroscopy for determination the optical proprieties of thin films.The experimental results show that: the films have hexagonal structure at the type (wurtzite), the average size of grains varies from 20.11 to 32.45 nm, the transmittance of the films equals 80% in visible rang and the band gap is varied between 3.274 and 3.282 eV, when the solution flow rate increases from 50 to 150 ml/h.

Method for the determination of lignin content of a sample by flash pyrolysis in an atmosphere of hydrogen or helium and method therefor

NASA Technical Reports Server (NTRS)

Shakkottai, Parthasarathy (Inventor); Kwack, Eug Y. (Inventor); Lawson, Daniel D. (Inventor)

1991-01-01

The lignin content of wood, paper pulp or other material containing lignin (such as filter paper soaked in black liquor) is more readily determined by flash pyrolysis of the sample at approximately 550.degree. C. in a reducing atmosphere of hydrogen or in an inert atmosphere of helium followed by a rapid analysis of the product gas by a mass spectrometer. The heated pyrolysis unit as fabricated comprises a small platinum cup welded to an electrically-heated stainless steel ribbon with control means for programmed short duration (1.5 sec, approximately) heating and means for continuous flow of hydrogen or helium. The pyrolysis products enter an electron-ionization mode mass spectrometer for spectral evaluation. Lignin content is obtained from certain ratios of integrated ion currents of many mass spectral lines, the ratios being linearly related to the Kappa number of Klason lignin.

Qualitative and quantitative analysis of pyrolysis oil by gas chromatography with flame ionization detection and comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry.

PubMed

Sfetsas, Themistoklis; Michailof, Chrysa; Lappas, Angelos; Li, Qiangyi; Kneale, Brian

2011-05-27

Pyrolysis oils have attracted a lot of interest, as they are liquid energy carriers and general sources of chemicals. In this work, gas chromatography with flame ionization detector (GC-FID) and two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC-TOFMS) techniques were used to provide both qualitative and quantitative results of the analysis of three different pyrolysis oils. The chromatographic methods and parameters were optimized and solvent choice and separation restrictions are discussed. Pyrolysis oil samples were diluted in suitable organic solvent and were analyzed by GC×GC-TOFMS. An average of 300 compounds were detected and identified in all three samples using the ChromaToF (Leco) software. The deconvoluted spectra were compared with the NIST software library for correct matching. Group type classification was performed by use of the ChromaToF software. The quantification of 11 selected compounds was performed by means of a multiple-point external calibration curve. Afterwards, the pyrolysis oils were extracted with water, and the aqueous phase was analyzed both by GC-FID and, after proper change of solvent, by GC×GC-TOFMS. As previously, the selected compounds were quantified by both techniques, by means of multiple point external calibration curves. The parameters of the calibration curves were calculated by weighted linear regression analysis. The limit of detection, limit of quantitation and linearity range for each standard compound with each method are presented. The potency of GC×GC-TOFMS for an efficient mapping of the pyrolysis oil is undisputable, and the possibility of using it for quantification as well has been demonstrated. On the other hand, the GC-FID analysis provides reliable results that allow for a rapid screening of the pyrolysis oil. To the best of our knowledge, very few papers have been reported with quantification attempts on pyrolysis oil samples using GC×GC-TOFMS most of which make use of the internal standard method. This work provides the ground for further analysis of pyrolysis oils of diverse sources for a rational design of both their production and utilization process. Copyright © 2010 Elsevier B.V. All rights reserved.

Comparison of petroleum generation kinetics by isothermal hydrous and nonisothermal open-system pyrolysis

USGS Publications Warehouse

Lewan, M.D.; Ruble, T.E.

2002-01-01

This study compares kinetic parameters determined by open-system pyrolysis and hydrous pyrolysis using aliquots of source rocks containing different kerogen types. Kinetic parameters derived from these two pyrolysis methods not only differ in the conditions employed and products generated, but also in the derivation of the kinetic parameters (i.e., isothermal linear regression and non-isothermal nonlinear regression). Results of this comparative study show that there is no correlation between kinetic parameters derived from hydrous pyrolysis and open-system pyrolysis. Hydrous-pyrolysis kinetic parameters determine narrow oil windows that occur over a wide range of temperatures and depths depending in part on the organic-sulfur content of the original kerogen. Conversely, open-system kinetic parameters determine broad oil windows that show no significant differences with kerogen types or their organic-sulfur contents. Comparisons of the kinetic parameters in a hypothetical thermal-burial history (2.5 ??C/my) show open-system kinetic parameters significantly underestimate the extent and timing of oil generation for Type-US kerogen and significantly overestimate the extent and timing of petroleum formation for Type-I kerogen compared to hydrous pyrolysis kinetic parameters. These hypothetical differences determined by the kinetic parameters are supported by natural thermal-burial histories for the Naokelekan source rock (Type-IIS kerogen) in the Zagros basin of Iraq and for the Green River Formation (Type-I kerogen) in the Uinta basin of Utah. Differences in extent and timing of oil generation determined by open-system pyrolysis and hydrous pyrolysis can be attributed to the former not adequately simulating natural oil generation conditions, products, and mechanisms.

Effect of pyrolysis temperature and air flow on toxicity of gases from a polycarbonate polymer

NASA Technical Reports Server (NTRS)

Hilado, C. J.; Brick, V. E.; Brauer, D. P.

1978-01-01

A polycarbonate polymer was evaluated for toxicity of pyrolysis gases generated at various temperatures without forced air flow and with 1 L/min air flow, using the toxicity screening test method developed at the University of San Francisco. Time to various animal responses decreased with increasing pyrolysis temperature over the range from 500 C to 800 C. There appeared to be no significant toxic effects at 400 C and lower temperatures.

Zone heating for fluidized bed silane pyrolysis

NASA Technical Reports Server (NTRS)

Iya, Sridhar K. (Inventor)

1987-01-01

An improved heated fluidized bed reactor and method for the production of high purity polycrystalline silicon by silane pyrolysis wherein silicon seed particles are heated in an upper heating zone of the reactor and admixed with particles in a lower reaction zone, in which zone a silane-containing gas stream, having passed through a lower cooled gas distribution zone not conducive to silane pyrolysis, contacts the heated seed particles whereon the silane is heterogeneously reduced to silicon.

Method of pyrolyzing brown coal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michel, W.; Heberlein, I.; Ossowski, M.

A two-step method and apparatus are disclosed based on the fluidized bed principle, for the production of coke, rich gas and pyrolysis tar, with the object of executing the method in a compact apparatus arrangement, with high energy efficiency and high throughput capacity. This is accomplished by a sequence in which the fine grains removed from the drying vapor mixture are removed from the actual pyrolysis process, and a hot gas, alien to the carbonization, is used as fluidization medium in the pyrolysis reactor, and with a hot gas-high performance separator being used for the dust separation from the pyrolysismore » gas, with the combustion exhaust gas produced in the combustion chamber being used for the indirect heating of the fluidization medium, for the pre-heating of the gas, which is alien to the carbonization, and for the direct heating in the dryer. The dryer has a double casing in the area of the fluidized bed, and a mixing chamber is arranged directly underneath its initial flow bottom, while the pyrolysis reactor is directly connected to the combustion chamber and the pre-heater.« less

A new method for spray deposit assessment

Treesearch

Chester M. Himel; Leland Vaughn; Raymond P. Miskus; Arthur D. Moore

1965-01-01

Solid fluorescent particles suspended in a spray liquid are distributed in direct proportion to the size of the spray droplets. Use of solid fluorescent particles is the basis of a new method for visual recognition of the size and number of droplets impinging on target and nontarget portions of sprayed areas.

Process for forming exoergic structures with the use of a plasma

DOEpatents

Kelly, M.D.

1987-05-29

A method of forming exoergic structures, as well as exoergic structures produced by the method, is provided. The method comprises the steps of passing a plasma-forming gas through a plasma spray gun, forming a plasma spray, introducing exoergic material into the plasma spray and directing the plasma spray toward a substrate, and allowing the exoergic material to become molten in the plasma spray and to thereafter impinge on the substrate to form a solid mass of exoergic material, the shape of which corresponds to the shape of the substrate.

The Development of an Environmentally Compliant, Multi-Functional Aerospace Coating Using Molecular- and Nano-Engineering Methods

DTIC Science & Technology

2006-10-02

Al -TM-RE) alloy which could by spray applied using various deposition routes or deposited as a powder that is...corrosion properties of various spray deposited alloys from their properties as defective coatings on 2024-T3. "* HVOF spray deposited and cold spray ...layer. "* A method has been developed to distinguish the intrinsic corrosion properties of various spray deposited

Oil shale derived pollutant control materials and methods and apparatuses for producing and utilizing the same

DOEpatents

Boardman, Richard D.; Carrington, Robert A.

2010-05-04

Pollution control substances may be formed from the combustion of oil shale, which may produce a kerogen-based pyrolysis gas and shale sorbent, each of which may be used to reduce, absorb, or adsorb pollutants in pollution producing combustion processes, pyrolysis processes, or other reaction processes. Pyrolysis gases produced during the combustion or gasification of oil shale may also be used as a combustion gas or may be processed or otherwise refined to produce synthetic gases and fuels.

Innovative Processing of Composites for Ultra-High Temperature Applications. Book 1

DTIC Science & Technology

1993-11-01

pyrolysis step (in which the polymer is converted at higher temperatures to a SiC -rich ceramic). However, curing in air also leads to the high oxygen...The fac’ that the ceramic the vinylic SiC precursor, i.e., a compound or polymer resulting from pyrolysis of the vinylic precursor re- having vinylic...12 %herein said atmosphere 1. A method of preparing preceramic SiC fibers hay- 65 utilized for pyrolysis ik a reactime atmosphere contain- ing a very

Pyrolysis and catalytic pyrolysis as a recycling method of waste CDs originating from polycarbonate and HIPS.

PubMed

Antonakou, E V; Kalogiannis, K G; Stephanidis, S D; Triantafyllidis, K S; Lappas, A A; Achilias, D S

2014-12-01

Pyrolysis appears to be a promising recycling process since it could convert the disposed polymers to hydrocarbon based fuels or various useful chemicals. In the current study, two model polymers found in WEEEs, namely polycarbonate (PC) and high impact polystyrene (HIPS) and their counterparts found in waste commercial Compact Discs (CDs) were pyrolysed in a bench scale reactor. Both, thermal pyrolysis and pyrolysis in the presence of two catalytic materials (basic MgO and acidic ZSM-5 zeolite) was performed for all four types of polymers. Results have shown significant recovery of the monomers and valuable chemicals (phenols in the case of PC and aromatic hydrocarbons in the case of HIPS), while catalysts seem to decrease the selectivity towards the monomers and enhance the selectivity towards other desirable compounds. Copyright © 2014 Elsevier Ltd. All rights reserved.

Estimating the Temperature Experienced by Biomass Particles during Fast Pyrolysis Using Microscopic Analysis of Biochars

DOE PAGES

Thompson, Logan C.; Ciesielski, Peter N.; Jarvis, Mark W.; ...

2017-07-12

Here, biomass particles can experience variable thermal conditions during fast pyrolysis due to differences in their size and morphology, and from local temperature variations within a reactor. These differences lead to increased heterogeneity of the chemical products obtained in the pyrolysis vapors and bio-oil. Here we present a simple, high-throughput method to investigate the thermal history experienced by large ensembles of particles during fast pyrolysis by imaging and quantitative image analysis. We present a correlation between the surface luminance (darkness) of the biochar particle and the highest temperature that it experienced during pyrolysis. Next, we apply this correlation to large,more » heterogeneous ensembles of char particles produced in a laminar entrained flow reactor (LEFR). The results are used to interpret the actual temperature distributions delivered by the reactor over a range of operating conditions.« less

A study on the formation of solid state nanoscale materials using polyhedral borane compounds

NASA Astrophysics Data System (ADS)

Romero, Jennifer V.

The formation of boron containing materials using a variety of methods was explored. The pyrolysis of a metal boride precursor solution can be accomplished using a one-source method by combining TiCl4, B10H 14 and CH3CN in one reaction vessel and pyrolyzing it at temperatures above 900 °C. Amorphous dark blue colored films were obtained after the pyrolysis reactions. Well-defined spherical shaped grains or particles were observed by SEM. The amorphous films generated contained titanium, however, the determination of the boron content of the films was inconclusive. This one pot method making metal boride thin films has the advantage of being able to dictate the stoichiometry of the reactants. Another part of this work represents the first report of both the use of metal boride materials and the use of a titanium-based compound for the formation of nanotubes. This method provides a facile method for generating well-formed boron-containing carbon nanotubes in a "one-pot" process through an efficient aerosol process. The formation of metal boride corrosion resistant layers was also explored. It was shown that metallic substrates can be effectively boronized using paste mixtures containing boron carbide and borax. The formation of a Fe4B 2 iron boride phase was achieved, however, this iron boride phase does not give enough corrosion protection. The formation of a corrosion resistant metal boride coating with strong adhesion was accomplished by boronization of a thermal sprayed nickel layer on the surface of steel. Surfactants were explored as possible nanoreactors in which metal boride nanoparticles could be formed to use as nanotube growth catalyst via room temperature reaction. Different surfactants were used, but none of them successfully generated very well dispersed metal boride nanoparticles. Nanoparticles with varying shapes and sizes were generated which were highly amorphous. The carboxylic acid derivative of closo-C2B 10 cages was explored as a ligand in the hydrothermal preparation of coordination polymers with zinc salts. It was found that the stability of the cage is apparently insufficient under these conditions and cage degradation was observed. Consequently, a preliminary investigation of the preparation of dipyridyl derivatives of both the closo-C2B 10 and the closo-B12 cages was performed.

Effects of ionic liquid to water ratio as a composite medium for the synthesis of LiFePO4 for battery

NASA Astrophysics Data System (ADS)

Tith, Rany; Dutta, Jaydeep; Jung, Kichang; Martinez-Morales, Alfredo A.

2017-05-01

LiFePO4 is a highly researched cathode material that serves as an alternative material for traditional commercial lithiumion batteries such as LiCoO2. Currently, there are a number of different methods to synthesize LiFePO4 including: hydrothermal, solid state, spray pyrolysis, and coprecipitation. Our proposed method has the potential to provide an ecologically friendly and economically competitive way to synthesize LiFePO4 by utilizing ionic liquid and water, as a composite synthesis medium. The addition of water to ionic liquid can be beneficial as it can act as a mineralizer to bring insoluble precursors to form LiFePO4 seed crystals. Furthermore, this method provides the possibility of recycling the ionic liquid for repeated synthesis processes. In this work, we study the effects of ionic liquid to water ratio on the crystallinity and morphology of the synthesized material. Our group was able to conclude a reaction medium utilizing a ratio of equal parts of 1-ethyl-3-methyl imidazolium trifluoromethane sulfonate (EMIM Otf) and water, or a slightly favored ionic liquid ratio, increases the efficacy of the synthesis route. Crystallinity and purity was determined by X-ray diffraction (XRD), scanning electron microscopy (SEM) was used to determine morphology and crystal sizes, and energy dispersion spectroscopy (EDX) was used for elemental analysis.

High-Performance Spray-Deposited Indium Doped ZnO Thin Film: Structural, Morphological, Electrical, Optical, and Photoluminescence Study

NASA Astrophysics Data System (ADS)

Asl, Hassan Zare; Rozati, Seyed Mohammad

2018-03-01

In this study, high-quality indium doped zinc oxide thin films were deposited using the spray pyrolysis technique, and the substrate temperature varied from 450°C to 550°C with steps of 25°C with the aim of investigating the effect of substrate temperature. It was found that as the temperature increased, the resistivity of the films decreased to the extent that it was as low as 5.34 × 10-3 Ω cm for the one deposited at 500°C; however, it slightly increased for the resulting film at 550°C. Although the carrier concentration mostly increased with temperature, it appeared that the carrier mobility was the parameter mainly governing the conductivity variation. In addition, the average transparency of the deposited films at 500°C, 525°C and 550°C was around 87% (400-800 nm), which makes them outstanding transparent conductive oxide films. Moreover, the crystallite size and strain of the resulting films were estimated via the Williamson-Hall method. The results revealed a considerable reduction in the crystallite size and strain up to 500°C followed by a rise at higher substrate temperature. Based on both the surface and cross-section field emission scanning electron microscope images, the film resulting at 500°C was highly compacted and crack free, which can explain the enlargement of the carrier mobility (10.9 cm2 V-1 s-1) in this film. Finally, a detailed photoluminescence study revealed several peaks in the spectrum and the variation of the two major peaks appeared to have correlation with the carrier concentration.

The stabilization of tannery sludge and the character of humic acid-like during low temperature pyrolysis.

PubMed

Ma, Hongrui; Gao, Mao; Hua, Li; Chao, Hao; Xu, Jing

2015-11-01

Tannery sludge contained plenty of organic matter, and the organic substance stability had direct impact on its derived chars' utilization. In this paper, the stabilization of tannery sludge and the variation of humic acid-like (HAL) extracted by different methods were investigated in a magnetic stirring reactor under low temperature pyrolysis of 100-400 °C. Results showed that the aromatic structure of pyrolysis chars increased with the increase of temperature and time. The char contained highly aromatic structure and relatively small dissolved organic matters (DOM) at 300 °C. The similar behaviors appeared in two HAL series by different extraction methods. The N content, H/C value, and aliphatic structures of HAL decreased with the increase of pyrolysis temperature, while the C/N value and aromatic structures increased with the rise of pyrolysis temperature. The composition and functional groups of HAL were similar with the purchased humic acid (HA). The fluorescence spectra revealed that two main peaks were found at Ex/Em = 239/363-368 nm and 283/359-368 nm in each HAL series from raw and 100 °C pyrolysis tannery sludge, representing a protein-like matter. The new peak appeared at Ex/Em = 263-283/388 nm in each HAL series from 200 °C pyrolysis tannery sludge-represented humic acid-like matter. The fluorescence intensity increased strongly compared to the other two peak intensity. Therefore, the humification of organic matter was increased by pyrolyzing. Notably, the HAL from 200 °C pyrolysis tannery sludge contained simple molecular structure, and the polycondensation increased but with a relative lower humification degree compared to soil HAL and purchased HA. Therefore, the sludge needs further oxidation. The humic substance was negligible by direct extraction when the temperature was 300 and 400 °C.

Pyrolysis kinetic and product analysis of different microalgal biomass by distributed activation energy model and pyrolysis-gas chromatography-mass spectrometry.

PubMed

Yang, Xuewei; Zhang, Rui; Fu, Juan; Geng, Shu; Cheng, Jay Jiayang; Sun, Yuan

2014-07-01

To assess the energy potential of different microalgae, Chlorella sorokiniana and Monoraphidium were selected for studying the pyrolytic behavior at different heating rates with the analytical method of thermogravimetric analysis (TG), distributed activation energy model (DAEM) and pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS). Results presented that Monoraphidium 3s35 showed superiority for pyrolysis at low heating rate. Calculated by DAEM, during the conversion rate range from 0.1 to 0.7, the activation energies of C. sorokiniana 21 were much lower than that of Monoraphidium 3s35. Both C. sorokiniana 21 and Monoraphidium 3s35 can produce certain amount (up to 20.50%) of alkane compounds, with 9-Octadecyne (C18H34) as the primary compound. Short-chain alkanes (C7-C13) with unsaturated carbon can be released in the pyrolysis at 500°C for both microalgal biomass. It was also observed that the pyrolysis of C. sorokiniana 21 released more alcohol compounds, while Monoraphidium 3s35 produced more saccharides. Copyright © 2014 Elsevier Ltd. All rights reserved.

An approach for upgrading biomass and pyrolysis product quality using a combination of aqueous phase bio-oil washing and torrefaction pretreatment.

PubMed

Chen, Dengyu; Cen, Kehui; Jing, Xichun; Gao, Jinghui; Li, Chen; Ma, Zhongqing

2017-06-01

Bio-oil undergoes phase separation because of poor stability. Practical application of aqueous phase bio-oil is challenging. In this study, a novel approach that combines aqueous phase bio-oil washing and torrefaction pretreatment was used to upgrade the biomass and pyrolysis product quality. The effects of individual and combined pretreatments on cotton stalk pyrolysis were studied using TG-FTIR and a fixed bed reactor. The results showed that the aqueous phase bio-oil washing pretreatment removed metals and resolved the two pyrolysis peaks in the DTG curve. Importantly, it increased the bio-oil yield and improved the pyrolysis product quality. For example, the water and acid content of bio-oil decreased significantly along with an increase in phenol formation, and the heating value of non-condensable gases improved, and these were more pronounced when combined with torrefaction pretreatment. Therefore, the combined pretreatment is a promising method, which would contribute to the development of polygeneration pyrolysis technology. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characteristics and kinetics study of simultaneous pyrolysis of microalgae Chlorella vulgaris, wood and polypropylene through TGA.

PubMed

Azizi, Kolsoom; Keshavarz Moraveji, Mostafa; Abedini Najafabadi, Hamed

2017-11-01

Thermal decomposition behavior and kinetics of microalgae Chlorella vulgaris, wood and polypropylene were investigated using thermogravimetric analysis (TGA). Experiments were carried out at heating rates of 10, 20 and 40°C/min from ambient temperature to 600°C. The results show that pyrolysis process of C. vulgaris and wood can be divided into three stages while pyrolysis of polypropylene occurs almost totally in one step. It is shown that wood can delay the pyrolysis of microalgae while microalgae can accelerate the pyrolysis of wood. The existence of polymer during the pyrolysis of microalgae or wood will lead to two divided groups of peaks in DTG curve of mixtures. The results showed that interaction is inhibitive rather than synergistic during the decomposition process of materials. Kinetics of process is studied by the Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO). The average E values obtained from FWO and KAS methods were 131.228 and 142.678kJ/mol, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cumulative effects of bamboo sawdust addition on pyrolysis of sewage sludge: Biochar properties and environmental risk from metals.

PubMed

Jin, Junwei; Wang, Minyan; Cao, Yucheng; Wu, Shengchun; Liang, Peng; Li, Yanan; Zhang, Jianyun; Zhang, Jin; Wong, Ming Hung; Shan, Shengdao; Christie, Peter

2017-03-01

A novel type of biochar was produced by mixing bamboo sawdust with sewage sludge (1:1, w/w) via a co-pyrolysis process at 400-600°C. Changes in physico-chemical properties and the intrinsic speciation of metals were investigated before and after pyrolysis. Co-pyrolysis resulted in a lower biochar yield but a higher C content in the end product compared with use of sludge alone as the raw material. FT-IR analysis indicates that phosphine derivatives containing PH bonds were formed in the co-pyrolyzed biochars. In addition, co-pyrolysis of sludge with bamboo sawdust transformed the potentially toxic metals in the sludge into more stable fractions, leading to a considerable decrease in their direct toxicity and bioavailability in the co-pyrolyzed biochar. In conclusion, the co-pyrolysis technology provides a feasible method for the safe disposal of metal-contaminated sewage sludge in an attempt to minimize the environmental risk from potentially toxic metals after land application. Copyright © 2016 Elsevier Ltd. All rights reserved.

Numerical Approach to Wood Pyrolysis in Considerating Heat Transfer in Reactor Chamber

NASA Astrophysics Data System (ADS)

Idris, M.; Novalia, U.

2017-03-01

Pyrolysis is the decomposition process of solid biomass into gas, tar and charcoal through thermochemical methods. The composition of biomass consists of cellulose hemi cellulose and lignin, which each will decompose at different temperatures. Currently pyrolysis has again become an important topic to be discussed. Many researchers make and install the pyrolysis reactor to convert biomass waste into clean energy hardware that can be used to help supply energy that has a crisis. Additionally the clean energy derived from biomass waste is a renewable energy, in addition to abundant source also reduce exhaust emissions of fossil energy that causes global warming. Pyrolysis is a method that has long been known by humans, but until now little is known about the phenomenon of the pyrolysis process that occurs in the reactor. One of the Pyrolysis’s phenomena is the heat transfer process from the temperature of the heat source in the reactor and heat the solid waste of biomass. The solid waste of biomass question in this research is rubber wood obtained from one of the company’s home furnishings. Therefore, this study aimed to describe the process of heat transfer in the reactor during the process. ANSYS software was prepared to make the simulation of heat transfer phenomena at the pyrolysis reactor. That’s the numerical calculation carried out for 1200 seconds. Comparison of temperature performed at T1, T2 and T3 to ensure that thermal conductivity is calculated by numerical accordance with experimental data. The distribution of temperature in the reactor chamber specifies the picture that excellent heat conduction effect of the wood near or attached to wooden components, cellulose, hemicellulose and lignin down into gas.

Synthesis of carbon nanomaterials from different pyrolysis techniques: a review

NASA Astrophysics Data System (ADS)

Umer Zahid, Muhammad; Pervaiz, Erum; Hussain, Arshad; Shahzad, Muhammad Imran; Niazi, Muhammad Bilal Khan

2018-05-01

In the current age, the significance of carbon-based nanomaterials for many applications has made the efforts for the facile synthesis methods from abundantly available wastes in a cost-effective way. Pyrolysis in a broad spectrum is commonly employed for the synthesis of carbon nanostructures by thermally treating the organic waste. The mechanism of growth of the nanoparticles determines the functional distribution of nanoparticles based on the growing size, medium, and physio-chemical properties. Carbon nanomaterial’s growth is a complicated process which is profoundly influenced by temperature, catalyst, and type of precursor. Nowadays, significant progress has been made in improving nanomaterial’s growth techniques, opening new paths for commercial production of carbon-based nanomaterials. The most promising are the methods involving hydrocarbon-rich organic waste as the feed source. In this review, synthesis of carbon-based nanomaterials, specifically carbon nanotubes (CNTs), Carbon nanofibers (CNFs) and Graphene (G) are discussed by different pyrolysis techniques. Furthermore, the review explores recent advancements made in the context of pyrolysis.

Optical Characterization of Tb3+:BaHfO3 Thin Films by Means of Photoacoustic Spectroscopy

NASA Astrophysics Data System (ADS)

Jiménez Flores, Yolanda; Nogal, Uriel; Suárez Quezada, Víctor Manuel; Rojas-Trigos, José Bruno

2018-06-01

In this work, the synthesis and optical characterization of Al2O3/Tb3+:BaHfO3/Al2O3 heterostructure, grown by ultrasonic spray pyrolysis technique are reported. The X-ray diffraction patterns corroborate that the scintillator layer structure corresponds to perovskite structure, while the elemental chemical composition of it is close to the optimal stoichiometry, but showing barium vacancies. The empirical determination of the optical bandgap energy, achieved by means of the photoacoustic spectroscopy technique, set a principal direct band gap in 3.8 eV, but evidencing the existence of a larger indirect bandgap also. The photoluminescent spectroscopy measurements show that the heterostructure has an intense fluorescent response, congruent to the principal emission lines of trivalent terbium, as was intended to.

Bismuth molybdate thick films as ethanol sensor

NASA Astrophysics Data System (ADS)

Jain, Kiran; Kumar, Vipin; Gupta, H. P.; Rastogi, A. C.

2003-10-01

Ethanol sensitivity of bismuth molybdate thick films and sintered pellets were investigated. Sintered pellets were prepared by traditional ceramic processing. Thick films were prepared by metallorganic decomposition process. Ethanol gas sensitivity was measured at various temperatures and concentrations. Thick films of alpha phase bismuth molybdate prepared by spray pyrolysis showed a very fast response to ethanol detection. The response time for the bulk samples is about 40 sec which decreased to about 6 sec for thick films at an operating temperature of 300°C. An extremely low level approximately 10 ppm detection and fast response makes this technique ideal for sensor element fabrication for detection and estimation of alcohol in breath-analyzer. Unlike SnO2, the resistance of these sensors is not affected by humidity at the operating temperature.

Toward Portable Breath Acetone Analysis for Diabetes Detection

PubMed Central

Righettoni, Marco; Tricoli, Antonio

2013-01-01

Diabetes is a lifelong condition that may cause death and seriously affects the quality of life of a rapidly growing number of individuals. Acetone is a selective breath marker for diabetes that may contribute to the monitoring of related metabolic disorder and thus simplify the management of this illness. Here, the overall performance of Si-doped WO3 nanoparticles made by flame spray pyrolysis as portable acetone detectors is critically reviewed focusing on the requirements for medical diagnostic. The effect of flow rate, chamber volume and acetone dissociation within the measuring chamber are discussed with respect to the calibration of the sensor response. The challenges for the fabrication of portable breath acetone sensors based on chemo-resistive detectors are underlined indicating possible solutions and novel research directions. PMID:21828897

Surfactant modified SnO2 nanostructured thin film for improved sensing performance of LPG and ammonia

NASA Astrophysics Data System (ADS)

Kumari, K. Prasanna; Thomas, Boben

2017-05-01

SnO2 nanostructured thin films have been successfully synthesized by way of spray pyrolysis from surfactant added solution. The X-ray diffraction pattern discloses the tetragonal rutile phase of the deposited SnO2 films, which experience a grain size reduction from 35 nm to 19 nm, on the addition of PVP surfactant in precursor. Gas sensing investigations on the surfactant modified film show considerable LPG and NH3 response at a lower operating temperature of 150°C. Quick response (˜20s) and fast recovery (˜30s) are the main features of these sensors. The measurement of AC conductivity of the sample allows understanding the conduction mechanism and sensing action for to enhance the detection sensitivity greatly.

Process for forming exoergic structures with the use of a plasma

DOEpatents

Kelly, Michael D.

1989-02-21

A method of forming exoergic structures, as well as exoergic structures produced by the method, is provided. The method comprises the steps of passing a plasma-forming gas through a plasma spray gun, forming a plasma spray, introducing exoergic material into the plasma spray and directing the plasma spray toward a substrate, and allowing the exoergic material to become molten, without chemically reacting in the plasma spray and to thereafter impinge on the substrate to form a solid mass of exoergic material, the shape of which corresponds to the shape of the substrate.

Comparison of KCl denuders with the pyrolysis method and calibration using HgBr2 at an in-service AMNET site

NASA Astrophysics Data System (ADS)

McClure, C.; Jaffe, D. A.; Edgerton, E.; Jansen, J. J.

2013-12-01

During the summer of 2013, we initiated a project to examine the performance of Tekran measurements of Gaseous Oxidized Mercury (GOM) with a pyrolysis method at the North Birmingham SEARCH site. Measurements started in June 2013 and will run until September 2013. This project responds to recent studies that indicate problems with the KCl denuder method for collection of GOM (e.g. Lyman et al., 2010; Gustin et al., 2013; Ambrose et al., 2013). For this project, we compared two GOM measurement systems, one using the KCl denuder method and a second method using high temperature pyrolysis of Hg compounds and detection of the resulting Hg0 vapors. Both instruments were also calibrated using an HgBr2 source to understand the recovery of one possible atmospheric GOM constituent. Both instruments sampled from a common, heated manifold. Past work has shown that in order to fully transmit HgBr2 sample lines must be made from PFA lines and heated to 100 °C. The transmission rate of HgBr2 during this project is approximately 90% over 25 feet of sample tubing at this temperature. Very preliminary results from this study have found that the transmitted HgBr2 is captured with 95% efficiency in carbon-scrubbed ambient air for both the KCl denuder and the pyrolysis method. However, the denuder method appears to be significantly less efficient in the capture of GOM when sampling unaltered ambient air versus the pyrolysis validation of total Hg0. Therefore, calibration of GOM measurements is essential in order to accurately correct for fluctuations in the GOM capture efficiency. We have also found that calibrations for GOM can be done routinely in the field and that these are essential to fully understand the GOM measurements. At present our calibration system is performed manually, but in principle this method could be readily automated.

Measuring Spray Droplet Size from Agricultural Nozzles Using Laser Diffraction

PubMed Central

Fritz, Bradley K.; Hoffmann, W. Clint

2016-01-01

When making an application of any crop protection material such as an herbicide or pesticide, the applicator uses a variety of skills and information to make an application so that the material reaches the target site (i.e., plant). Information critical in this process is the droplet size that a particular spray nozzle, spray pressure, and spray solution combination generates, as droplet size greatly influences product efficacy and how the spray moves through the environment. Researchers and product manufacturers commonly use laser diffraction equipment to measure the spray droplet size in laboratory wind tunnels. The work presented here describes methods used in making spray droplet size measurements with laser diffraction equipment for both ground and aerial application scenarios that can be used to ensure inter- and intra-laboratory precision while minimizing sampling bias associated with laser diffraction systems. Maintaining critical measurement distances and concurrent airflow throughout the testing process is key to this precision. Real time data quality analysis is also critical to preventing excess variation in the data or extraneous inclusion of erroneous data. Some limitations of this method include atypical spray nozzles, spray solutions or application conditions that result in spray streams that do not fully atomize within the measurement distances discussed. Successful adaption of this method can provide a highly efficient method for evaluation of the performance of agrochemical spray application nozzles under a variety of operational settings. Also discussed are potential experimental design considerations that can be included to enhance functionality of the data collected. PMID:27684589

Co-pyrolysis behaviour and kinetic of two typical solid wastes in China and characterisation of activated carbon prepared from pyrolytic char.

PubMed

Ma, Yuhui; Niu, Ruxuan; Wang, Xiaona; Wang, Qunhui; Wang, Xiaoqiang; Sun, Xiaohong

2014-11-01

This is the first study on the co-pyrolysis of spent substrate of Pleurotus ostreatus and coal tar pitch, and the activated carbon prepared from the pyrolytic char. Thermogravimetry (TG) analysis was carried out taking spent substrate, coal tar pitch and spent substrate-coal tar pitch mixture. The activation energies of pyrolysis reactions were obtained via the Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose methods. The kinetic models were determined by the master-plots method. The activated carbons were characterised by N2-adsorption, Fourier transform infrared spectroscopy and X-ray diffraction. Experimental results demonstrated a synergistic effect happened during co-pyrolysis, which was characterised by a decreased maximum decomposition rate and an enhanced char yield. The average activation energies of the pyrolysis reactions of spent substrate, coal tar pitch and the mixture were 115.94, 72.92 and 94.38 kJ mol(-1) for the Flynn-Wall-Ozawa method, and 112.17, 65.62 and 89.91 kJ mol(-1) for the Kissinger-Akahira-Sunose method. The reaction model functions were f(α) = (1-α)(3.42), (1-α)(1.72) and (1-α)(3.07) for spent substrate, coal tar pitch and the mixture, respectively. The mixture char-derived activated carbon had a Brunauer-Emmett-Teller surface area up to 1337 m(2) g(-1) and a total pore volume of 0.680 cm(3) g(-1). Mixing spent substrate with coal tar pitch led to the creation of more micropores and a higher surface area compared with the single spent substrate and coal tar pitch char. Also, the mixture char-derived activated carbon had a higher proportion of aromatic stacking. This study provides a reference for the utilisation of spent substrate and coal tar pitch via co-pyrolysis, and their pyrolytic char as a promising precursor of activated carbon. © The Author(s) 2014.

Developments in the formulation and delivery of spray dried vaccines.

PubMed

Kanojia, Gaurav; Have, Rimko Ten; Soema, Peter C; Frijlink, Henderik; Amorij, Jean-Pierre; Kersten, Gideon

2017-10-03

Spray drying is a promising method for the stabilization of vaccines, which are usually formulated as liquids. Usually, vaccine stability is improved by spray drying in the presence of a range of excipients. Unlike freeze drying, there is no freezing step involved, thus the damage related to this step is avoided. The edge of spray drying resides in its ability for particles to be engineered to desired requirements, which can be used in various vaccine delivery methods and routes. Although several spray dried vaccines have shown encouraging preclinical results, the number of vaccines that have been tested in clinical trials is limited, indicating a relatively new area of vaccine stabilization and delivery. This article reviews the current status of spray dried vaccine formulations and delivery methods. In particular it discusses the impact of process stresses on vaccine integrity, the application of excipients in spray drying of vaccines, process and formulation optimization strategies based on Design of Experiment approaches as well as opportunities for future application of spray dried vaccine powders for vaccine delivery.

Pyrolysis characteristics and kinetics of acid tar waste from crude benzol refining: A thermogravimetry-mass spectrometry analysis.

PubMed

Chihobo, Chido H; Chowdhury, Arindrajit; Kuipa, Pardon K; Simbi, David J

2016-12-01

Pyrolysis is an attractive thermochemical conversion technology that may be utilised as a safe disposal option for acid tar waste. The kinetics of acid tar pyrolysis were investigated using thermogravimetry coupled with mass spectrometry under a nitrogen atmosphere at different heating rates of 10, 15 and 20 K min -1 The thermogravimetric analysis shows three major reaction peaks centred around 178 °C, 258 °C, and 336 °C corresponding to the successive degradation of water soluble lower molecular mass sulphonic acids, sulphonated high molecular mass hydrocarbons, and high molecular mass hydrocarbons. The kinetic parameters were evaluated using the iso-conversional Kissinger-Akahira-Sunose method. A variation in the activation energy with conversion revealed that the pyrolysis of the acid tar waste progresses through complex multi-step kinetics. Mass spectrometry results revealed a predominance of gases such as hydrogen, methane and carbon monoxide, implying that the pyrolysis of acid tar waste is potentially an energy source. Thus the pyrolysis of acid tar waste may present a viable option for its environmental treatment. There are however, some limitations imposed by the co-evolution of corrosive gaseous components for which appropriate considerations must be provided in both pyrolysis reactor design and selection of construction materials. © The Author(s) 2016.

Life cycle analysis of switchgrass converted via pyrolysis, gasification, and fermentation

USDA-ARS?s Scientific Manuscript database

The US is promoting and developing low carbon fuel sources. Perennial bioenergy crops such as switchgrass (Panicum virgatum L.) are one viable source for low carbon transportation fuels. The objective is to determine the net greenhouse gas (GHG) emissions from different conversion methods (pyrolysi...

Low temperature isothermal pyrolysis of cellulose

Treesearch

A. Broido; M. Weinstein

1971-01-01

By providing continuous weight measurement, thermogravimetry, even for isothermal experiments, offers a major advantage over the classical methods of determining weight-change curves in complex pyrolysis reactions. Thus, even minor weight changes, readily detectable on a continuous record, furnish clues concerning the reaction sequences and indicate conditions under...

Development of the Basis for an Analytical Protocol for Feeds and Products of Bio-oil Hydrotreatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oasmaa, Anja; Kuoppala, Eeva; Elliott, Douglas C.

2012-04-02

Methods for easily following the main changes in the composition, stability, and acidity of bio-oil in hydrotreatment are presented. The correlation to more conventional methods is provided. Depending on the final use the upgrading requirement is different. This will create challenges also for the analytical protocol. Polar pyrolysis liquids and their products can be divided into five main groups with solvent fractionation the change in which is easy to follow. This method has over ten years been successfully used for comparison of fast pyrolysis bio-oil quality, and the changes during handling, and storage, provides the basis of the analytical protocolmore » presented in this paper. The method has most recently been used also for characterisation of bio-oil hydrotreatment products. Discussion on the use of gas chromatographic and spectroscopic methods is provided. In addition, fuel oil analyses suitable for fast pyrolysis bio-oils and hydrotreatment products are discussed.« less

A demonstration of the antimicrobial effectiveness of various copper surfaces

PubMed Central

2013-01-01

Background Bacterial contamination on touch surfaces results in increased risk of infection. In the last few decades, work has been done on the antimicrobial properties of copper and its alloys against a range of micro-organisms threatening public health in food processing, healthcare and air conditioning applications; however, an optimum copper method of surface deposition and mass structure has not been identified. Results A proof-of-concept study of the disinfection effectiveness of three copper surfaces was performed. The surfaces were produced by the deposition of copper using three methods of thermal spray, namely, plasma spray, wire arc spray and cold spray The surfaces were then inoculated with meticillin-resistant Staphylococcus aureus (MRSA). After a two hour exposure to the surfaces, the surviving MRSA were assayed and the results compared. The differences in the copper depositions produced by the three thermal spray methods were examined in order to explain the mechanism that causes the observed differences in MRSA killing efficiencies. The cold spray deposition method was significantly more effective than the other methods. It was determined that work hardening caused by the high velocity particle impacts created by the cold spray technique results in a copper microstructure that enhances ionic diffusion, and copper ions are principally responsible for antimicrobial activity. Conclusions This test showed significant microbiologic differences between coatings produced by different spray techniques and demonstrates the importance of the copper application technique. The cold spray technique shows superior anti-microbial effectiveness caused by the high impact velocity imparted to the sprayed particles which results in high dislocation density and high ionic diffusivity. PMID:23537176

Facile synthesis of antimony-doped tin oxide nanoparticles by a polymer-pyrolysis method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yuan-Qing, E-mail: yqli@mail.ipc.ac.cn; Wang, Jian-Lei; Fu, Shao-Yun, E-mail: syfu@mail.ipc.ac.cn

2010-06-15

In this article, antimony-doped tin oxide (ATO) nanoparticles was synthesized by a facile polymer-pyrolysis method. The pyrolysis behaviors of the polymer precursors prepared via in situ polymerization of metal salts and acrylic acid were analyzed by simultaneous thermogravimetric and differential scanning calorimetry (TG-DSC). The structural and morphological characteristics of the products were studied by powder X-ray diffraction (XRD) and transmission electron microscope (TEM). The results reveal that the ATO nanoparticles calcined at 600 {sup o}C show good crystallinity with the cassiterite structure and cubic-spherical like morphology. The average particle size of ATO decreases from 200 to 15 nm as themore » Sb doping content increases from 5 mol% to 15 mol%. Electrical resistivity measurement shows that the resistivity for the 10-13 mol% Sb-doped SnO{sub 2} nanoparticles is reduced by more than three orders compared with the pure SnO{sub 2} nanoparticles. In addition, due to its versatility this polymer-pyrolysis method can be extended to facile synthesis of other doped n-type semiconductor, such as In, Ga, Al doped ZnO, Sn doped In{sub 2}O{sub 3}.« less

A fluorescent imaging technique for quantifying spray deposits on plant leaves

USDA-ARS?s Scientific Manuscript database

Because of the unique characteristics of electrostatically-charged sprays, use of traditional methods to quantify deposition from these sprays has been challenging. A new fluorescent imaging technique was developed to quantify spray deposits from electrostatically-charged sprays on natural plant lea...

Recycling WEEE: Extraction and concentration of silver from waste crystalline silicon photovoltaic modules.

PubMed

Dias, Pablo; Javimczik, Selene; Benevit, Mariana; Veit, Hugo; Bernardes, Andréa Moura

2016-11-01

Photovoltaic modules (or panels) are important power generators with limited lifespans. The modules contain known pollutants and valuable materials such as silicon, silver, copper, aluminum and glass. Thus, recycling such waste is of great importance. To date, there have been few published studies on recycling silver from silicon photovoltaic panels, even though silicon technology represents the majority of the photovoltaic market. In this study, the extraction of silver from waste modules is justified and evaluated. It is shown that the silver content in crystalline silicon photovoltaic modules reaches 600g/t. Moreover, two methods to concentrate silver from waste modules were studied, and the use of pyrolysis was evaluated. In the first method, the modules were milled, sieved and leached in 64% nitric acid solution with 99% sodium chloride; the silver concentration yield was 94%. In the second method, photovoltaic modules were milled, sieved, subjected to pyrolysis at 500°C and leached in 64% nitric acid solution with 99% sodium chloride; the silver concentration yield was 92%. The first method is preferred as it consumes less energy and presents a higher yield of silver. This study shows that the use of pyrolysis does not assist in the extraction of silver, as the yield was similar for both methods with and without pyrolysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Depolymerization of lignin via co-pyrolysis with 1,4-butanediol in a microwave reactor

USDA-ARS?s Scientific Manuscript database

The production of valuable compounds from low cost but abundant residual lignin has proven to be challenging. The lack of effective biochemical lignin depolymerization processes has led many to focus on thermochemical conversion methods. Bench scale microwave pyrolysis of lignin has been performed...

Characterization of fast-pyrolysis bio-oil distillation residues and their potential applications

USDA-ARS?s Scientific Manuscript database

A typical petroleum refinery makes use of the vacuum gas oil by cracking the large molecular weight compounds into light fuel hydrocarbons. For various types of fast pyrolysis bio-oil, successful analogous methods for processing heavy fractions could expedite integration into a petroleum refinery fo...

Methods for detecting the mobility of trace elements during medium-temperature pyrolysis

USGS Publications Warehouse

Shiley, R.H.; Konopka, K.L.; Cahill, R.A.; Hinckley, C.C.; Smith, Gerard V.; Twardowska, H.; Saporoschenko, Mykola

1983-01-01

The mobility (volatility) of trace elements in coal during pyrolysis has been studied for distances of up to 40 cm between the coal and the trace element collector, which was graphite or a baffled solvent trap. Nineteen elements not previously recorded as mobile were detected. ?? 1983.

Synthesis and Magnetic Properties of Ni-DOPED ZnO Thin Films: Experimental and AB INITIO Study

NASA Astrophysics Data System (ADS)

Rouchdi, M.; Salmani, E.; Hat, A. El; Hassanain, N.; Mzerd, A.

Structural and magnetic properties of Zn1-xNixO thin films and diluted magnetic semiconductors have been investigated. This sample has been synthesized using a spray pyrolysis technique with a stoechiometric mixture of zinc acetate (C4H6O4Znṡ2H2O) and Nickel acetate (C4H6O4Niṡ 2H2O) on a heated glass substrate at 450∘C. The films were characterized by X-ray diffraction (XRD), UV-Vis spectrophotometry and Hall Effect measurements. These films of ZnO crystallized in the hexagonal Wurtzite structure. The optical study showed that the band-gap energy was increased, from 3.3eV to 3.5eV, with increasing the Ni concentration. The film resistivity was affected by Ni-doping, and the best resistivity value 1.15×10-2 (Ω cm) was obtained for the film doped with 2 at.% Ni. The electronic structure and optical properties of the Wurtzite structure Zn1-xNixO were obtained by first-principles calculations using the Korringa-Kohn-Rostoker method combined with the coherent potential approximation (CPA), as well as CPA confirm our results.

Nickel doping effect on properties of sprayed In2S3 films

NASA Astrophysics Data System (ADS)

Kraini, M.; Bouguila, N.; El Ghoul, J.

2018-03-01

Nickel doped In2S3 films have been prepared by the chemical spray pyrolysis technique at 350 °C on glass substrates. The Ni doping level was changed by varying Ni:In molar ratio from 0 to 4% in solution. The structural studies reveal that the Ni-doped In2S3 films are polycrystalline and exhibit a cubic structure. As the Ni:In molar ratio increases, the crystallite size decreases from 27.5 to 23 nm and RMS roughness values increase from 12 to 18 nm, respectively. The presence of Ni in the deposited films was confirmed by energy dispersive spectroscopy. Raman studies show different peaks related to In2S3 phase and do not reveal any secondary phases of In-Ni and Ni-S. The transmission coefficient is about 70-55% in the visible region and 85-75% in near-infrared region. The band gap energy increases from 2.66 to 2.82 eV for direct transitions with the increase of Ni:In ratio from 0 to 4%. The refractive index values of In2S3:Ni thin films decrease from 2.46 to 2.40 and the extinction coefficient values are in the range 0.01-0.20.

The calculation of band gap energy in zinc oxide films

NASA Astrophysics Data System (ADS)

Arif, Ali; Belahssen, Okba; Gareh, Salim; Benramache, Said

2015-01-01

We investigated the optical properties of undoped zinc oxide thin films as the n-type semiconductor; the thin films were deposited at different precursor molarities by ultrasonic spray and spray pyrolysis techniques. The thin films were deposited at different substrate temperatures ranging between 200 and 500 °C. In this paper, we present a new approach to control the optical gap energy of ZnO thin films by concentration of the ZnO solution and substrate temperatures from experimental data, which were published in international journals. The model proposed to calculate the band gap energy with the Urbach energy was investigated. The relation between the experimental data and theoretical calculation suggests that the band gap energies are predominantly estimated by the Urbach energies, film transparency, and concentration of the ZnO solution and substrate temperatures. The measurements by these proposal models are in qualitative agreements with the experimental data; the correlation coefficient values were varied in the range 0.96-0.99999, indicating high quality representation of data based on Equation (2), so that the relative errors of all calculation are smaller than 4%. Thus, one can suppose that the undoped ZnO thin films are chemically purer and have many fewer defects and less disorder owing to an almost complete chemical decomposition and contained higher optical band gap energy.

Surface properties of sprayed and electrodeposited ZnO rod layers

NASA Astrophysics Data System (ADS)

Gromyko, I.; Krunks, M.; Dedova, T.; Katerski, A.; Klauson, D.; Oja Acik, I.

2017-05-01

Herein we present a comparative study on as-deposited, two-month-stored, and heat-treated ZnO rods obtained by spray pyrolysis (SP) at 550 °C, and electrodeposition (ED) at 80 °C. The aim of the study is to establish the reason for different behaviour of wettability and photocatalytic activity (PA) of SP and ED rods. Samples were studied using XPS, SEM, XRD, Raman, contact angle (CA) measurements and photocatalytic oxidation of doxycycline. Wettability and PA are mainly controlled by surface composition rather than by morphology. The relative amount of hydroxyl groups on the surface of as-deposited ED rods is four times higher compared to as-deposited SP rods. Opposite to SP rods, ED rods contain oxygen vacancy defects (Vo). Therefore, as-deposited ED rods are superhydrophilic (CA ∼ 3°) and show highest PA among studied samples, being three times higher compared to SP rods (removing of 75% of doxycycline after 30 min). It was revealed that as-deposited ED rods are inclined to faster contamination. The amount of Cdbnd C groups on the surface of aged ED rods is six times higher compared to aged SP rods. Stored ED samples become hydrophobic (CA ∼ 120°) and PA decreases sharply while SP rods remain hydrophilic (CA ∼ 50°), being more resistive to the contamination.

A systematic probe in the properties of spray coated mixed spinel films of cobalt and manganese

NASA Astrophysics Data System (ADS)

Grace Victoria, S.; Moses Ezhil Raj, A.

2018-01-01

The multiple oxidation states of manganese and cobalt in cobalt manganese oxides play a crucial role in shaping up the vivid properties thus evoking curiosity among researchers. In the present work, mixed spinel films of CoMn(CoMn)2O4 were coated on glass substrates by the spray pyrolysis technique with different precursor concentrations of the acetate salts of the metals in ethyl alcohol. XRD investigations revealed an intermediate tetragonal spinel structure between cubic MnCo2O4 and tetragonal Mn3O4 (JCPDS 18-0410) with predominant orientation along (311) plane. The tetragonal distortion from cubic symmetry may be due to high Mn2+ ion content at octahedral sites. Raman spectroscopy highlighted two typical emission peaks characteristic of the deposited mixed spinel oxides. Functional groups were assigned with the aid of FTIR spectral analysis to the observed absorption bands. The binding energies of the photo-electron peaks observed for the transition metal ions and the oxygenated ions were recorded by XPS. The results indicated that the divalent and trivalent ions of cobalt co-existed with the divalent manganese ions. AFM images revealed vertically aligned columnar grains. The electrical measurements indicated conduction mechanism through jumps of polarons. Optical absorption revealed wide band gap energy of 3.76 eV.

Fluxing template-assisted synthesis of sponge-like Fe2O3 microspheres toward efficient catalysis for CO oxidation

NASA Astrophysics Data System (ADS)

Li, Wenge; Hu, Yanjie; Jiang, Hao; Jiang, Yi; Wang, Yang; Huang, Su; Biswas, Pratim; Li, Chunzhong

2018-06-01

Constructing a porous architecture is a considerable strategy to enhance the catalytic activity of metal oxides catalysts for CO oxidation. In this work, we have developed porous sponge-like Fe2O3 microspheres by employing a facile aerosol spray pyrolysis. The NaNO3 salt in the spray solution plays a crucial role as a fluxing sacrifice template in the formation of the sponge-like structure, in which a high surface area of 216.2 m2 g-1 and an average pore size of 4 nm are obtained. This novel Fe2O3 catalyst exhibits an improved catalytic activity compared to usual iron oxides catalysts. Nearly 50% CO conversion at a relatively low temperature of 200 °C and 100% CO conversion at 300 °C at a space velocity of 60 000 ml h-1 g-1 are achieved. Furthermore, it displays an outstanding catalytic stability without distinct decay for 1000 min in a continuous stream at 300 °C. In addition to the effect of plentiful adsorption sites for the gas reactant, the promoted catalytic performance is also attributed to the function of abundant OH groups rooted in the large surface of the sponge-like structure, which induces faster reaction rate of CO oxidation via a bicarbonate route.

Synergistic effects of Mo and F doping on the quality factor of ZnO thin films prepared by a fully automated home-made nebulizer spray technique

NASA Astrophysics Data System (ADS)

Ravichandran, K.; Dineshbabu, N.; Arun, T.; Manivasaham, A.; Sindhuja, E.

2017-01-01

Transparent conducting oxide films of undoped, Mo doped, Mo + F co-doped ZnO were deposited using a facile homemade nebulizer spray pyrolysis technique. The effects of Mo and F doping on the structural, optical, electrical and surface morphological properties were investigated using XRD, UV-vis-NIR spectroscopy, I-V and Hall probe techniques, FESEM and AFM, and XPS, respectively. The XRD analysis confirms that all the films are well crystallized with hexagonal wurtzite structure. All the synthesized samples exhibit high transmittance (above 85%) in the visible region. The current-voltage (I-V) characteristics show the ohmic conduction nature of the films. The Hall probe measurements show that the synergistic effects of Mo and F doping cause desirable improvements in the quality factor of the ZnO films. A minimum resistivity of 5.12 × 10-3 Ω cm with remarkably higher values of mobility and carrier concentration is achieved for Mo (2 at.%) + F (15 at.%) co-doped ZnO films. A considerable variation in the intensity of deep level emission caused by Mo and F doping is observed in the photoluminescence (PL) studies. The presence of the constituent elements in the samples is confirmed by XPS analysis.

Electrochemical Supercapacitive Performance of Spray-Deposited NiO Electrodes

NASA Astrophysics Data System (ADS)

Yadav, Abhijit A.; Chavan, U. J.

2018-04-01

Transition-metal oxides with porous structure are considered for use as promising electrodes for high-performance supercapacitors. Nanocrystalline nickel oxide (NiO) thin films have been prepared as active material for supercapacitors by spray pyrolysis. In this study, the effects of the film thickness on its structural, morphological, optical, electrical, and electrochemical properties were studied. X-ray diffraction analysis revealed cubic structure with average crystalline size of around 21 nm. Scanning electron microscopy showed porous morphology. The optical bandgap decreased from 3.04 eV to 2.97 eV with increase in the film thickness. Electrical resistivity measurements indicated semiconducting behavior. Cyclic voltammetry and galvanostatic charge/discharge study revealed good pseudocapacitive behavior. Specific capacitance of 564 F g-1 at scan rate of 5 mV s-1 and 553 F g-1 at current density of 1 A g-1 was observed. An NiO-based supercapacitor delivered specific energy of 22.8 W h kg-1 at specific power of 2.16 kW kg-1, and retained 93.01% specific capacitance at current density of 1 A g-1 after 1000 cycles. Therefore, taking advantage of the porous morphology that exists in the nanostructure, such NiO materials can be considered for use as promising electrodes for high-performance supercapacitors.

Lead (Pb2+) and copper (Cu2+) remediation from water using superparamagnetic maghemite (γ-Fe2O3) nanoparticles synthesized by Flame Spray Pyrolysis (FSP).

PubMed

Rajput, Shalini; Singh, Lok P; Pittman, Charles U; Mohan, Dinesh

2017-04-15

Superparamagnetic maghemite (γ-Fe 2 O 3 ) nanoparticles of controllable morphology were successfully synthesized using a flame spray pyrolysis (FSP) technique. Their physico-chemical properties, size, morphology, and surface chemistries were determined using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), selected area electron diffraction patterns (SAED), SEM-EDX, scanning electron microscopy (SEM), and pH ZPC (6.3). Elemental contents before and after adsorption were identified using energy dispersive X-ray fluorescence (ED-XRF), energy dispersive X-ray analysis (EDX) and elemental mapping. Surface area (S BET 79.35m 2 /g) and size distribution analyses were conducted using a surface area analyzer and dynamic light scattering (DLS), respectively. The magnetic moment (44.5 at 300K and 50.16 at 2K) was determined using a physical properties measurement system (PPMS). The first adsorption study using γ-Fe 2 O 3 nanoparticles synthesized by FSP to successfully remediate Pb 2+ and Cu 2+ from water is reported. Batch adsorption studies were carried out. An optimum pH of 5.0 was studied for Pb 2+ and Cu 2+ removal. Pb 2+ and Cu 2+ removal mechanisms by these maghemite nanoparticles were presented. The adsorption of Pb 2+ and Cu 2+ was highly pH-dependent. The metal ion uptake was mainly governed by electrostatic attractions. Sorption kinetic data followed the pseudo-second-order model. The Freundlich, Langmuir, Redlich-Peterson, Radke and Sips adsorption isotherm models were applied to interpret equilibrium data. The Freundlich and Langmuir isotherm equations best fit the respective equilibrium data for Pb 2+ and Cu 2+ . The maximum Langmuir adsorption capacities of these maghemite nanoparticles were 68.9mg/g at 45°C for Pb 2+ and 34.0mg/g at 25 °C for Cu 2+ . Thus, these maghemite nanoparticles made by FSP were readily prepared, characterized and showed promise for remediating heavy metal ions from aqueous solutions. Copyright © 2016 Elsevier Inc. All rights reserved.

Pyrolysis Strategies for Effective Utilization of Lignocellulosic and Algal Biomass

NASA Astrophysics Data System (ADS)

Maddi, Balakrishna

Pyrolysis is a processing technique involving thermal degradation of biomass in the absence of oxygen. The bio-oils obtained following the condensation of the pyrolysis vapors form a convenient starting point for valorizing the major components of lignocellulosic as well as algal biomass feed stocks for the production of fuels and value-added chemicals. Pyrolysis can be implemented on whole biomass or on residues left behind following standard fractionation methods. Microalgae and oil seeds predominantly consist of protein, carbohydrate and triglycerides, whereas lignocellulose is composed of carbohydrates (cellulose and hemicellulose) and lignin. The differences in the major components of these two types of biomass will necessitate different pyrolysis strategies to derive the optimal benefits from the resulting bio-oils. In this thesis, novel pyrolysis strategies were developed that enable efficient utilization of the bio-oils (and/or their vapors) from lignocellulose, algae, as well as oil seed feed stocks. With lignocellulosic feed stocks, pyrolysis of whole biomass as well as the lignin residue left behind following well-established pretreatment and saccharification (i.e., depolymerization of cellulose and hemicellulose to their monomeric-sugars) of the biomass was studied with and without catalysts. Following this, pyrolysis of (lipid-deficient) algae and lignocellulosic feed stocks, under similar reactor conditions, was performed for comparison of product (bio-oil, gas and bio-char) yields and composition. In spite of major differences in component bio-polymers, feedstock properties relevant to thermo-chemical conversions, such as overall C, H and O-content, C/O and H/C molar ratio as well as calorific values, were found to be similar for algae and lignocellulosic material. Bio-oil yields from algae and some lignocellulosic materials were similar; however, algal bio-oils were compositionally different and contained several N-compounds (most likely from protein degradation). Algal bio-char also had a significantly higher N-content. Overall, our results suggest that it is feasible to convert algal cultures deficient in lipids, such as nuisance algae obtained from natural blooms, into liquid fuels by thermochemical methods. Next, pyrolysis characteristics of each of the major components present in lignocellulosic as well as algal biomass were studied independently in a thermo-gravimetric analyzer, using model compounds. From those studies, we have established that, with algae and oil seed feed stocks, triglycerides degrade at distinctly higher temperatures (T>350 C) compared to both protein and carbohydrate fractions (T ~ 250-350 C). Similar trend was not seen for lignocellulosic biomass, where degradation temperature interval of lignin overlapped with that of carbohydrates. This unique trend observed for algal biomass (and oil seeds) can be exploited in multiple ways. First, it permits to separately collect high value triglyceride degradation products not contaminated with N-compounds from protein and oxygenates from carbohydrates; this observation formed the basis of a novel "pyrolytic fractionation technique" developed in this thesis. Second, it led to the development of a new and simple analytical method for rapid estimation of the triglyceride content of oleaginous feed stocks. Pyrolytic fractionation is a two-step pyrolysis approach that can be implemented for oleaginous feed stocks (algae and oil-seeds) to separately recover triglyceride degradation products as a "high-quality" bio-oil fraction. The first step is a low-temperature pyrolysis (T ~ 300-320 C) to produce bio-oils from degradation of protein and carbohydrate fractions. Solid residues left behind can subsequently be subjected to a second higher temperature pyrolysis (T ~ 420-430 C) to volatilize and/or degrade triglycerides to produce fatty acids and their derivatives (such as mono-, di- and tri-glycerides) and long chain hydrocarbons. Proof-of-concept micro-pyrolyser (Pyroprobe) and lab-scale fixed-bed experiments were performed using oleaginous algae (Chlorella Sp.) to establish pyrolytic fractionation technique and also to determine the yields of triglyceride-specific bio-oils. As expected, triglyceride-specific bio-oils have hydrocarbons and free fatty acids that were nearly free of water, organic acids and carbohydrate degradation products. Another unique feature of the fractional pyrolysis method is that it allows upgrading of the triglyceride-specific bio-oil vapors via in situ gas-phase hydro-deoxygenation to drop-in fuels (hydrocarbons), without the need to condense the vapors. Similarly, these vapors can also be converted to other value-added products such as fatty acid methyl esters and amides though efficient catalytic and non-catalytic in situ gas-phase conversion methods. Energy requirements for this new pyrolytic fractionation method were also assessed, using energy estimates for the individual steps obtained via differential scanning calorimetry experiments. A comparison of these energy needs against those of alternative thermal processing methods of algae (hydro-thermal processing) proposed in the literature established the viability of this new method. Finally, a new TGA-based analytical method was developed in this thesis for rapid quantification of the triglyceride content of oleaginous feed stocks, by exploiting the non-overlapping thermal degradation range of triglycerides and the other major components.

Image processing of vaporizing GDI sprays: a new curvature-based approach

NASA Astrophysics Data System (ADS)

Lazzaro, Maurizio; Ianniello, Roberto

2018-01-01

This article introduces an innovative method for the segmentation of Mie-scattering and schlieren images of GDI sprays. The contours of the liquid phase are obtained by segmenting the scattering images of the spray by means of optimal filtering of the image, relying on variational methods, and an original thresholding procedure based on an iterative application of Otsu’s method. The segmentation of schlieren images, to get the contours of the spray vapour phase, is obtained by exploiting the surface curvature of the image to strongly enhance the intensity texture due to the vapour density gradients. This approach allows one to unambiguously discern the whole vapour phase of the spray from the background. Additional information about the spray liquid phase can be obtained by thresholding filtered schlieren images. The potential of this method has been substantiated in the segmentation of schlieren and scattering images of a GDI spray of isooctane. The fuel, heated to 363 K, was injected into nitrogen at a density of 1.12 and 3.5 kg m-3 with temperatures of 333 K and 573 K.

Ex-situ catalytic pyrolysis of wastewater sewage sludge - A micro-pyrolysis study.

PubMed

Wang, Kaige; Zheng, Yan; Zhu, Xifeng; Brewer, Catherine E; Brown, Robert C

2017-05-01

Concerns over increasing amounts of sewage sludge and unsustainability of current disposal methods have led to development of alternative routes for sludge management. The large amount of organics in sewage sludge makes it potential feedstock for energy or fuel production via thermochemical pathways. In this study, ex-situ catalytic pyrolysis using HZSM-5 catalyst was explored for the production of olefinic and aromatic hydrocarbons and nutrient-rich char from sewage sludge. The optimal pyrolysis and catalysis temperatures were found to be 500°C and 600°C, respectively. Carbon yields of hydrocarbons from sewage sludge were higher than for lignocellulose; yield differences were attributed to the high extractives content in the sludge. Full recovery of most inorganic elements were found in the char, which suggests that catalyst deactivation maybe alleviated through ex-situ catalytic pyrolysis. Most of the nitrogen was retained in the char while 31.80% was released as ammonia, which suggests a potential for nitrogen recycling. Copyright © 2017 Elsevier Ltd. All rights reserved.

Thermal pyrolysis characteristics of macroalgae Cladophora glomerata.

PubMed

Gao, Wenhua; Chen, Kefu; Zeng, Jinsong; Xu, Jun; Wang, Bin

2017-11-01

The Cladophora glomerata (C. glomerata) is a kind of widely distributed macroalgae in the freshwater ecosystems. It primarily consists of carbohydrates that can be converted into biofuel by pyrolysis. In this study, thermogravimetric analysis (TGA) was used to investigate the thermal behavior and kinetics of C. glomerata during the pyrolysis process. The results showed that heating rates slightly affect the decomposition properties of C. glomerata; with the heating rates increasing, the maximum peak of weight loss rate shifted to higher temperatures. The activation energies of C. glomerata pyrolysis reaction were 244.25 and 238.07kJ/mol, respectively, as calculated by Friedman and Kissinger-Akahira-Sunose (KAS) methods. The pre-exponential factor and reaction order were determined by Coats-Redfern model, and applied to simulate the pyrolysis process of C. glomerata. The model calculated data and experimental data were consistent. This study could provide theoretical supports for designing C. glomerata conversion processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Coal Producer's Rubber Waste Processing Development

NASA Astrophysics Data System (ADS)

Makarevich, Evgeniya; Papin, Andrey; Nevedrov, Alexander; Cherkasova, Tatyana; Ignatova, Alla

2017-11-01

A large amount of rubber-containing waste, the bulk of which are worn automobile tires and conveyor belts, is produced at coal mining and coal processing enterprises using automobile tires, conveyor belts, etc. The volume of waste generated increases every year and reaches enormous proportions. The methods for processing rubber waste can be divided into three categories: grinding, pyrolysis (high and low temperature), and decomposition by means of chemical solvents. One of the known techniques of processing the worn-out tires is their regeneration, aimed at producing the new rubber substitute used in the production of rubber goods. However, the number of worn tires used for the production of regenerate does not exceed 20% of their total quantity. The new method for processing rubber waste through the pyrolysis process is considered in this article. Experimental data on the upgrading of the carbon residue of pyrolysis by the methods of heavy media separation, magnetic and vibroseparation, and thermal processing are presented.

Gas chromatography-mass spectrometric analysis of products from on-line pyrolysis/silylation of plant gums used as binding media

NASA Astrophysics Data System (ADS)

Chiantore, Oscar; Riedo, Chiara; Scalarone, Dominique

2009-07-01

Plant gums are complex polysaccharides used in the field of cultural heritage especially as binding media. Classification of polysaccharides may be achieved on the basis of monosaccharides composition after cleavage of glycosidic bond. Characterization of plant gums in works of art is complicated by the necessity of to use a method minimally invasive and requiring a small mount of sample. Pyrolisys is an useful method to obtain polysaccharides decomposition and generally pyrolysis products can be identified by the use of gas chromatography-mass spectrometry. This paper describes a method where two plant gums, arabic and tragacanth, were pyrolized in presence of silylating agents (HMDS e BSTFA alone and with TMCS as catalyst) using an on-line Py-GC/MS apparatus. Some characteristic trimethylsilyl derivatives of monosaccharides were identified on the basis of mass spectra. The presence of characteristic pyrolysis products of sugars allows to distinguish the two gums.

Apparatuses and methods for deoxygenating biomass-derived pyrolysis oil

DOEpatents

Kalnes, Tom N.

2015-12-29

Apparatuses and methods for deoxygenating a biomass-derived pyrolysis oil are provided herein. In one example, the method comprises of dividing a feedstock stream into first and second feedstock portions. The feedstock stream comprises the biomass-derived pyrolysis oil and has a temperature of about 60.degree. C. or less. The first feedstock portion is combined with a heated organic liquid stream to form a first heated diluted pyoil feed stream. The first heated diluted pyoil feed stream is contacted with a first deoxygenating catalyst in the presence of hydrogen to form an intermediate low-oxygen pyoil effluent. The second feedstock portion is combined with the intermediate low-oxygen pyoil effluent to form a second heated diluted pyoil feed stream. The second heated diluted pyoil feed stream is contacted with a second deoxygenating catalyst in the presence of hydrogen to form additional low-oxygen pyoil effluent.

Methods and apparatuses for deoxygenating pyrolysis oil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baird, Lance Awender; Brandvold, Timothy A.; Frey, Stanley Joseph

Methods and apparatuses are provided for deoxygenating pyrolysis oil. A method includes contacting a pyrolysis oil with a deoxygenation catalyst in a first reactor at deoxygenation conditions to produce a first reactor effluent. The first reactor effluent has a first oxygen concentration and a first hydrogen concentration, based on hydrocarbons in the first reactor effluent, and the first reactor effluent includes an aromatic compound. The first reactor effluent is contacted with a dehydrogenation catalyst in a second reactor at conditions that deoxygenate the first reactor effluent while preserving the aromatic compound to produce a second reactor effluent. The second reactormore » effluent has a second oxygen concentration lower than the first oxygen concentration and a second hydrogen concentration that is equal to or lower than the first hydrogen concentration, where the second oxygen concentration and the second hydrogen concentration are based on the hydrocarbons in the second reactor effluent.« less

Developments in the formulation and delivery of spray dried vaccines

PubMed Central

Kanojia, Gaurav; Have, Rimko ten; Soema, Peter C.; Frijlink, Henderik; Amorij, Jean-Pierre; Kersten, Gideon

2017-01-01

ABSTRACT Spray drying is a promising method for the stabilization of vaccines, which are usually formulated as liquids. Usually, vaccine stability is improved by spray drying in the presence of a range of excipients. Unlike freeze drying, there is no freezing step involved, thus the damage related to this step is avoided. The edge of spray drying resides in its ability for particles to be engineered to desired requirements, which can be used in various vaccine delivery methods and routes. Although several spray dried vaccines have shown encouraging preclinical results, the number of vaccines that have been tested in clinical trials is limited, indicating a relatively new area of vaccine stabilization and delivery. This article reviews the current status of spray dried vaccine formulations and delivery methods. In particular it discusses the impact of process stresses on vaccine integrity, the application of excipients in spray drying of vaccines, process and formulation optimization strategies based on Design of Experiment approaches as well as opportunities for future application of spray dried vaccine powders for vaccine delivery. PMID:28925794

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thompson, Logan C.; Ciesielski, Peter N.; Jarvis, Mark W.

Here, biomass particles can experience variable thermal conditions during fast pyrolysis due to differences in their size and morphology, and from local temperature variations within a reactor. These differences lead to increased heterogeneity of the chemical products obtained in the pyrolysis vapors and bio-oil. Here we present a simple, high-throughput method to investigate the thermal history experienced by large ensembles of particles during fast pyrolysis by imaging and quantitative image analysis. We present a correlation between the surface luminance (darkness) of the biochar particle and the highest temperature that it experienced during pyrolysis. Next, we apply this correlation to large,more » heterogeneous ensembles of char particles produced in a laminar entrained flow reactor (LEFR). The results are used to interpret the actual temperature distributions delivered by the reactor over a range of operating conditions.« less

Development of manufacturing process for large-diameter composite monofilaments by pyrolysis of resin-impregnated carbon-fiber bundles

NASA Technical Reports Server (NTRS)

Bradshaw, W. G.; Pinoli, P. C.; Vidoz, A. E.

1972-01-01

Large diameter, carbon-carbon composite, monofilaments were produced from the pyrolysis of organic precursor resins reinforced with high-strenght carbon fibers. The mechanical properties were measured before and after pyrolysis and the results were correlated with the properties of the constituents. The composite resulting from the combination of Thornel 75 and GW-173 resin precursor produced the highest tensile strength. The importance of matching strain-to-failure of fibers and matrix to obtain all the potential reinforcement of fibers is discussed. Methods are described to reduce, within the carbonaceous matrix, pyrolysis flaws which tend to reduce the composite strength. Preliminary studies are described which demonstrated the feasibility of fiber-matrix copyrolysis to alleviate matrix cracking and provide an improved matrix-fiber interfacial bonding.

Characterization of Source Signatures of Fine Roadway Particles by Pyrolysis-GC-MS

NASA Astrophysics Data System (ADS)

van Bergen, S. K.; Holmén, B. A.

2001-12-01

Fine particulate matter, defined as particles with an aerodynamic diameter less than 2.5 μ m (PM2.5), is of growing concern due to its detrimental effects on human health and the environment. Roadway traffic generates a significant fraction of PM2.5 in urban areas. Since exposure to fine particles derived from mobile sources commonly occurs, understanding the physicochemical processes that contribute to the generation, transport and atmospheric reactivity of roadway PM is important. Factors that influence the properties of roadway PM include: the mass, number and size distribution of the particles as well as their chemical composition. These factors are partially determined by the sources of the roadway particles. The focus of this effort is to identify unique organic chemical profiles of known roadway sources of PM using a new rapid characterization technique. A pyrolysis GC-MS analytical method is being developed to uniquely characterize the sources of roadway PM2.5 such as brake dust, tire wear, and direct emissions from diesel and gasoline engines. The source profiles will be used in conjunction with measurements of the composition of ambient roadway PM to determine the importance of the various roadway sources. The advantages of this technique over conventional solvent extractions include: smaller (mg) sample mass requirements, short extraction times and minimal sample handing. Preliminary two-step pyrolysis results will be presented for PM samples from individual sources and an ambient roadway. Specific analytical issues that will be discussed include: modifications of commercial pyrolysis hardware to improve reproducibility; desorption versus pyrolysis; developing appropriate pyrolysis programs for heterogenous sample materials; and method detection limits.

Organic Matter Detection on Mars by Pyrolysis-FTIR: An Analysis of Sensitivity and Mineral Matrix Effects

NASA Astrophysics Data System (ADS)

Gordon, Peter R.; Sephton, Mark A.

2016-11-01

Returning samples from Mars will require an effective method to assess and select the highest-priority geological materials. The ideal instrument for sample triage would be simple in operation, limited in its demand for resources, and rich in produced diagnostic information. Pyrolysis-Fourier infrared spectroscopy (pyrolysis-FTIR) is a potentially attractive triage instrument that considers both the past habitability of the sample depositional environment and the presence of organic matter that may reflect actual habitation. An important consideration for triage protocols is the sensitivity of the instrumental method. Experimental data indicate pyrolysis-FTIR sensitivities for organic matter at the tens of parts per million level. The mineral matrix in which the organic matter is hosted also has an influence on organic detection. To provide an insight into matrix effects, we mixed well-characterized organic matter with a variety of dry minerals, to represent the various inorganic matrices of Mars samples, prior to analysis. During pyrolysis-FTIR, serpentinites analogous to those on Mars indicative of the Phyllocian Era led to no negative effects on organic matter detection; sulfates analogous to those of the Theiikian Era led, in some instances, to the combustion of organic matter; and palagonites, which may represent samples from the Siderikian Era, led, in some instances, to the chlorination of organic matter. Any negative consequences brought about by these mineral effects can be mitigated by the correct choice of thermal extraction temperature. Our results offer an improved understanding of how pyrolysis-FTIR can perform during sample triage on Mars.

Analytical pyrolysis mass spectrometry: new vistas opened by temperature-resolved in-source PYMS

NASA Astrophysics Data System (ADS)

Boon, Jaap J.

1992-09-01

Analytical pyrolysis mass spectrometry (PYMS) is introduced and its applications to the analysis of synthetic polymers, biopolymers, biomacromolecular systems and geomacromolecules are critically reviewed. Analytical pyrolysis inside the ionisation chamber of a mass spectrometer, i.e. in-source PYMS, gives a complete inventory of the pyrolysis products evolved from a solid sample. The temperature-resolved nature of the experiment gives a good insight into the temperature dependence of the volatilisation and pyrolytic dissociation processes. Chemical ionisation techniques appear to be especially suitable for the analysis of oligomeric fragments released in early stages of the pyrolysis of polymer systems. Large oligomeric fragments were observed for linear polymers such as cellulose (pentadecamer), polyhydroxyoctanoic acid (tridecamer) and polyhydroxybutyric acid (heneicosamer). New in-source PYMS data are presented on artists' paints, the plant polysaccharides cellulose and xyloglucan, several microbial polyhydroxyalkanoates, wood and enzyme-digested wood, biodegraded roots and a fossil cuticle of Miocene age. On-line and off-line pyrolysis chromatography mass spectrometric approaches are also discussed. New data presented on high temperature gas chromatography--mass spectrometry of deuterio-reduced permethylated pyrolysates of cellulose lead to a better understanding of polysaccharide dissociation mechanisms. Pyrolysis as an on-line sample pretreatment method for organic macromolecules in combination with MS techniques is a very challenging field of mass spectrometry. Pyrolytic dissociation and desorption is not at all a chaotic process but proceeds according to very specific mechanisms.

Catalytic fast pyrolysis of biomass impregnated with potassium phosphate in a hydrogen atmosphere for the production of phenol and activated carbon

NASA Astrophysics Data System (ADS)

Lu, Qiang; Zhang, Zhen-xi; Wang, Xin; Guo, Hao-qiang; Cui, Min-shu; Yang, Yong-ping

2018-02-01

A new technique was proposed to co-produce phenol and activated carbon (AC) from catalytic fast pyrolysis of biomass impregnated with K3PO4 in a hydrogen atmosphere, followed by activation of the pyrolytic solid residues. Lab-scale catalytic fast pyrolysis experiments were performed to quantitatively determine the pyrolytic product distribution, as well as to investigate the effects of several factors on the phenol production, including pyrolysis atmosphere, catalyst type, biomass type, catalytic pyrolysis temperature, and catalyst impregnation content. In addition, the pyrolytic solid residues were activated to prepare ACs with high specific surface areas. The results indicated that phenol could be obtained due to the synergistic effects of K3PO4 and hydrogen atmosphere, with the yield and selectivity reaching 5.3 wt% and 17.8% from catalytic fast pyrolysis of poplar wood with 8 wt% K3PO4 at 550 oC in a hydrogen atmosphere. This technique was adaptable to different woody materials for phenol production. Moreover, gas product generated from the pyrolysis process was feasible to be recycled to provide the hydrogen atmosphere, instead of extra hydrogen supply. In addition, the pyrolytic solid residue was suitable for AC preparation, using CO2 activation method, the specific surface area was as high as 1605 m2/g.

Catalytic Fast Pyrolysis of Biomass Impregnated with Potassium Phosphate in a Hydrogen Atmosphere for the Production of Phenol and Activated Carbon

PubMed Central

Lu, Qiang; Zhang, Zhen-xi; Wang, Xin; Guo, Hao-qiang; Cui, Min-shu; Yang, Yong-ping

2018-01-01

A new technique was proposed to co-produce phenol and activated carbon (AC) from catalytic fast pyrolysis of biomass impregnated with K3PO4 in a hydrogen atmosphere, followed by activation of the pyrolytic solid residues. Lab-scale catalytic fast pyrolysis experiments were performed to quantitatively determine the pyrolytic product distribution, as well as to investigate the effects of several factors on the phenol production, including pyrolysis atmosphere, catalyst type, biomass type, catalytic pyrolysis temperature, and catalyst impregnation content. In addition, the pyrolytic solid residues were activated to prepare ACs with high specific surface areas. The results indicated that phenol could be obtained due to the synergistic effects of K3PO4 and hydrogen atmosphere, with the yield and selectivity reaching 5.3 wt% and 17.8% from catalytic fast pyrolysis of poplar wood with 8 wt% K3PO4 at 550°C in a hydrogen atmosphere. This technique was adaptable to different woody materials for phenol production. Moreover, gas product generated from the pyrolysis process was feasible to be recycled to provide the hydrogen atmosphere, instead of extra hydrogen supply. In addition, the pyrolytic solid residue was suitable for AC preparation, using CO2 activation method, the specific surface area was as high as 1,605 m2/g. PMID:29515994

Influence of pyrolysis temperature on properties and environmental safety of heavy metals in biochars derived from municipal sewage sludge.

PubMed

Jin, Junwei; Li, Yanan; Zhang, Jianyun; Wu, Shengchun; Cao, Yucheng; Liang, Peng; Zhang, Jin; Wong, Ming Hung; Wang, Minyan; Shan, Shengdao; Christie, Peter

2016-12-15

Dried raw sludge was pyrolyzed at temperatures ranging from 400 to 600°C at the increase of 50°C intervals to investigate the influence of pyrolysis temperature on properties and environmental safety of heavy metals in biochar derived from municipal sewage sludge. The sludge biochar yield decreased significantly with increasing pyrolysis temperature but the pH, ash content and specific surface area increased. Conversion of sludge to biochar markedly decreased the H/C and N/C ratios. FT-IR analysis confirmed a dramatic depletion of H and N and a higher degree of aromatic condensation in process of biochar formation at higher temperatures. The total concentrations of Cu, Zn, Pb, Cr, Mn, and Ni increased with conversion of sludge to biochar and increasing pyrolysis temperature. However, using BCR sequential extraction and analysis, it was found that most of the heavy metals existed in the oxizable and residual forms after pyrolysis, especially at 600°C, resulting in a significant reduction in their bioavailability, leading to a very low environmental risk of the biochar. The present study indicates pyrolysis is a promising sludge treatment method for heavy metals immobilization in biochar, and highlights the potential to minimize the harmful effects of biochar by controlling pyrolysis temperature. Copyright © 2016 Elsevier B.V. All rights reserved.

Catalytic Fast Pyrolysis of Biomass Impregnated with Potassium Phosphate in a Hydrogen Atmosphere for the Production of Phenol and Activated Carbon.

PubMed

Lu, Qiang; Zhang, Zhen-Xi; Wang, Xin; Guo, Hao-Qiang; Cui, Min-Shu; Yang, Yong-Ping

2018-01-01

A new technique was proposed to co-produce phenol and activated carbon (AC) from catalytic fast pyrolysis of biomass impregnated with K 3 PO 4 in a hydrogen atmosphere, followed by activation of the pyrolytic solid residues. Lab-scale catalytic fast pyrolysis experiments were performed to quantitatively determine the pyrolytic product distribution, as well as to investigate the effects of several factors on the phenol production, including pyrolysis atmosphere, catalyst type, biomass type, catalytic pyrolysis temperature, and catalyst impregnation content. In addition, the pyrolytic solid residues were activated to prepare ACs with high specific surface areas. The results indicated that phenol could be obtained due to the synergistic effects of K 3 PO 4 and hydrogen atmosphere, with the yield and selectivity reaching 5.3 wt% and 17.8% from catalytic fast pyrolysis of poplar wood with 8 wt% K 3 PO 4 at 550°C in a hydrogen atmosphere. This technique was adaptable to different woody materials for phenol production. Moreover, gas product generated from the pyrolysis process was feasible to be recycled to provide the hydrogen atmosphere, instead of extra hydrogen supply. In addition, the pyrolytic solid residue was suitable for AC preparation, using CO 2 activation method, the specific surface area was as high as 1,605 m 2 /g.

Use of air-assisted electrostatic spraying system (ESS)or the sprayed lethality in container(SLIC) method to deliver anticmicrobials onto the surface of beef subprimals to ... shiga toxin-producing cells of Escherichia coli

USDA-ARS?s Scientific Manuscript database

We evaluated the efficacy of an air-assisted electrostatic spraying system (ESS) and/or the Sprayed Lethality in Container (SLIC) method to deliver antimicrobials onto the surface of beef subprimals to reduce levels of Shiga toxin-producing Escherichia coli (STEC). Beef subprimals were surface inocu...

Kinetic Analysis of the Main Temperature Stage of Fast Pyrolysis

NASA Astrophysics Data System (ADS)

Yang, Xiaoxiao; Zhao, Yuying; Xu, Lanshu; Li, Rui

2017-10-01

Kinetics of the thermal decomposition of eucalyptus chips was evaluated using a high-rate thermogravimetric analyzer (BL-TGA) designed by our research group. The experiments were carried out under non-isothermal condition in order to determine the fast pyrolysis behavior of the main temperature stage (350-540ºC) at heating rates of 60, 120, 180, and 360ºC min-1. The Coats-Redfern integral method and four different reaction mechanism models were adopted to calculate the kinetic parameters including apparent activation energy and pre-exponential factor, and the Flynn-Wall-Ozawa method was employed to testify apparent activation energy. The results showed that estimation value was consistent with the values obtained by linear fitting equations, and the best-fit model for fast pyrolysis was found.

Pyrolysis kinetics and combustion of thin wood using advanced cone calorimetry test method

Treesearch

Mark A. Dietenberger

2011-01-01

Mechanistic pyrolysis kinetics analysis of extractives, holocellulose, and lignin in solid wood over entire heating regime was possible using specialized cone calorimeter test and new mathematical analysis tools. Added hardware components include: modified sample holder for thin specimen with tiny thermocouples, methane ring burner with stainless steel mesh above cone...

A simple, sensitive graphical method of treating thermogravimetric analysis data

Treesearch

Abraham Broido

1969-01-01

Thermogravimetric Analysis (TGA) is finding increasing utility in investigations of the pyrolysis and combustion behavior of materuals. Although a theoretical treatment of the TGA behavior of an idealized reaction is relatively straight-forward, major complications can be introduced when the reactions are complex, e.g., in the pyrolysis of cellulose, and when...

Use of a deuterated internal standard with pyrolysis-GC/MS dimeric marker analysis to quantify tire tread particles in the environment.

PubMed

Unice, Kenneth M; Kreider, Marisa L; Panko, Julie M

2012-11-08

Pyrolysis(pyr)-GC/MS analysis of characteristic thermal decomposition fragments has been previously used for qualitative fingerprinting of organic sources in environmental samples. A quantitative pyr-GC/MS method based on characteristic tire polymer pyrolysis products was developed for tread particle quantification in environmental matrices including soil, sediment, and air. The feasibility of quantitative pyr-GC/MS analysis of tread was confirmed in a method evaluation study using artificial soil spiked with known amounts of cryogenically generated tread. Tread concentration determined by blinded analyses was highly correlated (r2 ≥ 0.88) with the known tread spike concentration. Two critical refinements to the initial pyrolysis protocol were identified including use of an internal standard and quantification by the dimeric markers vinylcyclohexene and dipentene, which have good specificity for rubber polymer with no other appreciable environmental sources. A novel use of deuterated internal standards of similar polymeric structure was developed to correct the variable analyte recovery caused by sample size, matrix effects, and ion source variability. The resultant quantitative pyr-GC/MS protocol is reliable and transferable between laboratories.

Finding the chemistry in biomass pyrolysis: Millisecond chemical kinetics and visualization

NASA Astrophysics Data System (ADS)

Krumm, Christoph

Biomass pyrolysis is a promising thermochemical method for producing fuels and chemicals from renewable sources. Development of a fundamental understanding of biomass pyrolysis chemistry is difficult due to the multi-scale and multi-phase nature of the process; biomass length scales span 11 orders of magnitude and pyrolysis phenomena include solid, liquid, and gas phase chemistry in addition to heat and mass transfer. These complexities have a significant effect on chemical product distributions and lead to variability between reactor technologies. A major challenge in the study of biomass pyrolysis is the development of kinetic models capable of describing hundreds of millisecond-scale reactions of biomass into lower molecular weight products. In this work, a novel technique for studying biomass pyrolysis provides the first- ever experimental determination of kinetics and rates of formation of the primary products from cellulose pyrolysis, providing insight into the millisecond-scale chemical reaction mechanisms. These findings highlight the importance of heat and mass transport limitations for cellulose pyrolysis chemistry and are used to identify the length scales at which transport limitations become relevant during pyrolysis. Through this technique, a transition is identified, known as the reactive melting point, between low and high temperature depolymerization. The transition between two mechanisms of cellulose decompositions unifies the mechanisms that govern low temperature char formation, intermediate pyrolysis conditions, and high temperature gas formation. The conditions under which biomass undergoes pyrolysis, including modes of heat transfer, have been shown to significantly affect the distribution of biorenewable chemical and fuel products. High-speed photography is used to observe the liftoff of initially crystalline cellulose particles when impinged on a heated surface, known as the Leidenfrost effect for room-temperature liquids. Order-of-magnitude changes in the lifetime of cellulose particles are observed as a result of changing modes in heat transfer as cellulose intermediate liquid droplets wet and de-wet polished ceramic surfaces. Introduction of surface macroporosity is shown to completely inhibit the cellulose Leidenfrost effect, providing avenues for surface modification and reactor design to control particle heat transfer in industrial pyrolysis applications. Cellulosic particles on surfaces consisting of microstructured, asymmetric ratchets were observed to spontaneously move orthogonal to ratchet wells above the cellulose reactive Leidenfrost temperature (>750 °C). Evaluation of the accelerating particles supported the mechanism of propelling viscous forces (50-200 nN) from rectified pyrolysis vapors, thus providing the first example of biomass conveyors with no moving parts driven by high temperature for biofuel reactors. Combined knowledge of pyrolysis chemistry, kinetics, and heat and mass transport effects direct the design of the next generation pyrolysis reactors for tuning bio- oil quality and design of improved catalytic upgrading technology.

Quality characteristic of spray-drying egg white powders.

PubMed

Ma, Shuang; Zhao, Songning; Zhang, Yan; Yu, Yiding; Liu, Jingbo; Xu, Menglei

2013-10-01

Spray drying is a useful method for developing egg process and utilization. The objective of this study was to evaluate effects on spray drying condition of egg white. The optimized conditions were spraying flow 22 mL/min, feeding temperature 39.8 °C and inlet-air temperature 178.2 °C. Results of sulfydryl (SH) groups measurement indicated conformation structure have changed resulting in protein molecule occur S-S crosslinking phenomenon when heating. It led to free SH content decreased during spray drying process. There was almost no change of differential scanning calorimetry between fresh egg white and spray-drying egg white powder (EWP). For a given protein, the apparent SH reactivity is in turn influenced by the physico-chemical characteristics of the reactant. The phenomenon illustrated the thermal denaturation of these proteins was unrelated to their free SH contents. Color measurement was used to study browning level. EWP in optimized conditions revealed insignificant brown stain. Swelling capacity and scanning electron micrograph both proved well quality characteristic of spray-drying EWP. Results suggested spray drying under the optimized conditions present suitable and alternative method for egg processing industrial implementation. Egg food industrialization needs new drying method to extend shelf-life. The purpose of the study was to provide optimal process of healthy and nutritional instant spray-drying EWP and study quality characteristic of spray-drying EWP.

Graphene oxide wrapped croconic acid disodium salt for sodium ion battery electrodes

NASA Astrophysics Data System (ADS)

Luo, Chao; Zhu, Yujie; Xu, Yunhua; Liu, Yihang; Gao, Tao; Wang, Jing; Wang, Chunsheng

2014-03-01

Croconic acid disodium salt (CADS), a renewable or recyclable organic compound, is investigated as an anode material in sodium ion battery for the first time. The pristine micro-sized CADS delivers a high capacity of 246.7 mAh g-1, but it suffers from fast capacity decay during charge/discharge cycles. The detailed investigation reveals that the severe capacity loss is mainly attributed to the pulverization of CADS particles induced by the large volume change during sodiation/desodiation rather than the generally believed dissolution of CADS in the organic electrolyte. Minimizing the particle size can effectively suppress the pulverization, thus improving the cycling stability. Wrapping CADS with graphene oxide by ultrasonic spray pyrolysis can enhance the integration and conductivity of CADS electrodes, thus providing a high capacity of 293 mAh g-1.

Passivated iodine pentoxide oxidizer for potential biocidal nanoenergetic applications.

PubMed

Feng, Jingyu; Jian, Guoqiang; Liu, Qing; Zachariah, Michael R

2013-09-25

Iodine pentoxide (I2O5), also known as diiodine pentoxide, is a strong oxidizer which has been recently proposed as an iodine-rich oxidizer in nanoenergetic formulations, whose combustion products lead to molecular iodine as a biocidal agent. However, its highly hygroscopic nature hinders its performance as a strong oxidizer and an iodine releasing agent and prevents its implementation. In this work, we developed a gas phase assisted aerosol spray pyrolysis which enables creation of iron oxide passivated I2O5. Transmission electron microscopy elemental imaging as well as temperature-jump mass spectrometry confirmed the core shell nature of the material and the fact that I2O5 could be encapsulated in pure unhydrated form. Combustion performance finds an optimal coating thickness that enables combustion performance similar to a high performing CuO based thermite.

Optimizing biomass feedstock blends with respect to cost, supply, and quality for catalyzed and uncatalyzed fast pyrolysis applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thompson, Vicki S.; Aston, John E.; Lacey, Jeffrey A.

Here, biomass cost, quality and quantity are important parameters to consider when choosing feedstocks and locations for biorefineries. Biomass cost is dependent upon type, location, quantities available in a given area and logistics costs as well the quality needed for the biorefinery. Biomass quality depends upon type, growth conditions, weather, harvesting methods, storage conditions as well as any preprocessing methods used to improve quality. Biomass quantity depends heavily on location as well as growth conditions, weather, harvesting methods and storage conditions. This study examines how all three of these parameters affect the biomass mixture that is needed in a biomassmore » depot or biorefinery to achieve the lowest cost with the highest quality and at the quantities needed for biorefinery operation. Four biomass depots were proposed in South Carolina that would each process the predominant type of biomass available in that area and each produce 200,000 tons of feedstock per year. These depots would then feed a centrally located 800,000 ton biorefinery that would convert the feedstocks to pyrolysis oil using either catalyzed or uncatalyzed fast pyrolysis. The four depots each needed to produce different blends of biomass based upon the quantities available to them but still meet the minimum quality requirements for the biorefinery. Costs were minimized by using waste biomass resources such as construction and demolition waste, logging residues and forest residuals. Depending upon the quality specification required by the biorefinery, it was necessary to utilize preprocessing methods such as air classification and acid leaching to upgrade biomass quality. In the case of uncatalyzed fast pyrolysis, all four depots could produce biomass blends that were lower cost than the the preferred pyrolysis feedstock, clean pine, and meet quality and quantity specifications. For catalyzed fast pyrolysis, three of the four depots were able to produce blends that met both quality and quantity specifications at minimum cost. The fourth depot would not be able to produce a blend meeting specifications without increasing the supply radius for the depot.« less

Optimizing biomass feedstock blends with respect to cost, supply, and quality for catalyzed and uncatalyzed fast pyrolysis applications

DOE PAGES

Thompson, Vicki S.; Aston, John E.; Lacey, Jeffrey A.; ...

2017-05-24

Here, biomass cost, quality and quantity are important parameters to consider when choosing feedstocks and locations for biorefineries. Biomass cost is dependent upon type, location, quantities available in a given area and logistics costs as well the quality needed for the biorefinery. Biomass quality depends upon type, growth conditions, weather, harvesting methods, storage conditions as well as any preprocessing methods used to improve quality. Biomass quantity depends heavily on location as well as growth conditions, weather, harvesting methods and storage conditions. This study examines how all three of these parameters affect the biomass mixture that is needed in a biomassmore » depot or biorefinery to achieve the lowest cost with the highest quality and at the quantities needed for biorefinery operation. Four biomass depots were proposed in South Carolina that would each process the predominant type of biomass available in that area and each produce 200,000 tons of feedstock per year. These depots would then feed a centrally located 800,000 ton biorefinery that would convert the feedstocks to pyrolysis oil using either catalyzed or uncatalyzed fast pyrolysis. The four depots each needed to produce different blends of biomass based upon the quantities available to them but still meet the minimum quality requirements for the biorefinery. Costs were minimized by using waste biomass resources such as construction and demolition waste, logging residues and forest residuals. Depending upon the quality specification required by the biorefinery, it was necessary to utilize preprocessing methods such as air classification and acid leaching to upgrade biomass quality. In the case of uncatalyzed fast pyrolysis, all four depots could produce biomass blends that were lower cost than the the preferred pyrolysis feedstock, clean pine, and meet quality and quantity specifications. For catalyzed fast pyrolysis, three of the four depots were able to produce blends that met both quality and quantity specifications at minimum cost. The fourth depot would not be able to produce a blend meeting specifications without increasing the supply radius for the depot.« less

Development testing of large volume water sprays for warm fog dispersal

NASA Technical Reports Server (NTRS)

Keller, V. W.; Anderson, B. J.; Burns, R. A.; Lala, G. G.; Meyer, M. B.; Beard, K. V.

1986-01-01

A new brute-force method of warm fog dispersal is described. The method uses large volume recycled water sprays to create curtains of falling drops through which the fog is processed by the ambient wind and spray induced air flow. Fog droplets are removed by coalescence/rainout. The efficiency of the technique depends upon the drop size spectra in the spray, the height to which the spray can be projected, the efficiency with which fog laden air is processed through the curtain of spray, and the rate at which new fog may be formed due to temperature differences between the air and spray water. Results of a field test program, implemented to develop the data base necessary to assess the proposed method, are presented. Analytical calculations based upon the field test results indicate that this proposed method of warm fog dispersal is feasible. Even more convincingly, the technique was successfully demonstrated in the one natural fog event which occurred during the test program. Energy requirements for this technique are an order of magnitude less than those to operate a thermokinetic system. An important side benefit is the considerable emergency fire extinguishing capability it provides along the runway.

Research on pyrolysis behavior of Camellia sinensis branches via the Discrete Distributed Activation Energy Model.

PubMed

Zhou, Bingliang; Zhou, Jianbin; Zhang, Qisheng

2017-10-01

This study aims at investigating the pyrolysis behavior of Camellia sinensis branches by the Discrete Distributed Activation Energy Model (DAEM) and thermogravimetric experiments. Then the Discrete DAEM method is used to describe pyrolysis process of Camellia sinensis branches dominated by 12 characterized reactions. The decomposition mechanism of Camellia sinensis branches and interaction with components are observed. And the reaction at 350.77°C is a significant boundary of the first and second reaction range. The pyrolysis process of Camellia sinensis branches at the heating rate of 10,000°C/min is predicted and provides valuable references for gasification or combustion. The relationship and function between four typical indexes and heating rates from 10 to 10,000°C/min are revealed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Impact of Substrate Types on Structure and Emission of ZnO Nanocrystalline Films

NASA Astrophysics Data System (ADS)

Ballardo Rodriguez, I. Ch.; El Filali, B.; Díaz Cano, A. I.; Torchynska, T. V.

2018-02-01

Zinc oxide (ZnO) films were simultaneously synthesized by an ultrasonic spray pyrolysis (USP) method on p-type Si (100), silicon carbide polytype [6H-SiC (0001)], porous 6H-SiC and amorphous glass substrates with the aim of studying the impact of substrate types on the structure and emission of ZnO nanocrystalline films. Porous silicon carbide (P-SiC) was prepared by the electrochemical anodization method at a constant potential of 20 V and etching time of 12 min. ZnO films grown on the SiC and P-SiC substrates are characterized by a wurtzite crystal structure with preferential growth along the (002) direction and with grain sizes of 90-180 and 70-160 nm, respectively. ZnO films grown on the Si substrate have just some small irregular hexagonal islands. The amorphous glass substrate did not promote the formation of any regular crystal forms. The obtained x-ray diffraction and photoluminescence (PL) results have shown that the better ZnO film crystallinity and high PL intensity of near-band edge emissions were achieved in the films grown on the porous SiC and SiC substrates. The preferential growth and crystalline nature of ZnO films on the SiC substrate have been discussed from the point of view of the lattice parameter compatibility between ZnO and SiC crystals.

Total Acid Value Titration of Hydrotreated Biomass Fast Pyrolysis Oil: Determination of Carboxylic Acids and Phenolics with Multiple End-Point Detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Christensen, E.; Alleman, T. L.; McCormick, R. L.

Total acid value titration has long been used to estimate corrosive potential of petroleum crude oil and fuel oil products. The method commonly used for this measurement, ASTM D664, utilizes KOH in isopropanol as the titrant with potentiometric end point determination by pH sensing electrode and Ag/AgCl reference electrode with LiCl electrolyte. A natural application of the D664 method is titration of pyrolysis-derived bio-oil, which is a candidate for refinery upgrading to produce drop in fuels. Determining the total acid value of pyrolysis derived bio-oil has proven challenging and not necessarily amenable to the methodology employed for petroleum products duemore » to the different nature of acids present. We presented an acid value titration for bio-oil products in our previous publication which also utilizes potentiometry using tetrabutylammonium hydroxide in place of KOH as the titrant and tetraethylammonium bromide in place of LiCl as the reference electrolyte to improve the detection of these types of acids. This method was shown to detect numerous end points in samples of bio-oil that were not detected by D664. These end points were attributed to carboxylic acids and phenolics based on the results of HPLC and GC-MS studies. Additional work has led to refinement of the method and it has been established that both carboxylic acids and phenolics can be determined accurately. Use of pH buffer calibration to determine half-neutralization potentials of acids in conjunction with the analysis of model compounds has allowed us to conclude that this titration method is suitable for the determination of total acid value of pyrolysis oil and can be used to differentiate and quantify weak acid species. The measurement of phenolics in bio-oil is subject to a relatively high limit of detection, which may limit the utility of titrimetric methodology for characterizing the acidic potential of pyrolysis oil and products.« less

The pyrolysis characteristics of moso bamboo

Treesearch

Zehui Jiang; Zhijia Liu; Benhua Fei; Zhiyong Cai; Yan Yu; Xing’e Liu

2012-01-01

In the research, thermogravimetry (TG), a combination of thermogravimetry and Fourier transform infrared spectrometer (TG–FTIR) and X-ray diffraction (XRD) were used to investigate pyrolysis characteristics of moso bamboo (Phyllostachys pubescens). The Flynn–Wall–Ozawa and Coats–Redfern (modified) methods were used to determine the apparent activation energy (

Method for Biochar Passivation Using Low Percent Oxygen

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Kristin; Dupuis, Dan; Wilcox, Esther

2016-06-06

The thermochemical process development unit may be configured for pyrolysis or gasification. The pyrolysis unit operations include: feed transport system; entrained flow reactor; solids removal and collection; and liquid scrubbing, collection, and filtration. Char accumulates in the collection drums at a rate of ~1.5 kg/hr and must be passivated before it is stored or transported.

Pyrolysis kinetics and combustion of thin wood by an advanced cone caorimetry test method

Treesearch

Mark Dietenberger

2012-01-01

Pyrolysis kinetics analysis of extractives, holocellulose, and lignin in the solid redwood over the entire heating regime was possible by specialized cone calorimeter test and new mathematical analysis tools. Added hardware components include: modified sample holder for the thin specimen with tiny thermocouples, the methane ring burner with stainless-steel mesh above...

Formation of nanocarbon spheres by thermal treatment of woody char from fast pyrolysis process

Treesearch

Qiangu Yan; Hossein Toghiani; Zhiyong Cai; Jilei Zhang

2014-01-01

Influences of thermal treatment conditions of temperature, reaction cycle and time, and purge gas type on nanocarbon formation over bio-chars from fast pyrolysis and effects of thermal reaction cycle and purge gas type on bio-char surface functional groups were investigated by temperature-programmed desorption (TPD) and temperature programmed reduction methods....

Organic Matter Detection on Mars by Pyrolysis-FTIR: An Analysis of Sensitivity and Mineral Matrix Effects.

PubMed

Gordon, Peter R; Sephton, Mark A

2016-11-01

Returning samples from Mars will require an effective method to assess and select the highest-priority geological materials. The ideal instrument for sample triage would be simple in operation, limited in its demand for resources, and rich in produced diagnostic information. Pyrolysis-Fourier infrared spectroscopy (pyrolysis-FTIR) is a potentially attractive triage instrument that considers both the past habitability of the sample depositional environment and the presence of organic matter that may reflect actual habitation. An important consideration for triage protocols is the sensitivity of the instrumental method. Experimental data indicate pyrolysis-FTIR sensitivities for organic matter at the tens of parts per million level. The mineral matrix in which the organic matter is hosted also has an influence on organic detection. To provide an insight into matrix effects, we mixed well-characterized organic matter with a variety of dry minerals, to represent the various inorganic matrices of Mars samples, prior to analysis. During pyrolysis-FTIR, serpentinites analogous to those on Mars indicative of the Phyllocian Era led to no negative effects on organic matter detection; sulfates analogous to those of the Theiikian Era led, in some instances, to the combustion of organic matter; and palagonites, which may represent samples from the Siderikian Era, led, in some instances, to the chlorination of organic matter. Any negative consequences brought about by these mineral effects can be mitigated by the correct choice of thermal extraction temperature. Our results offer an improved understanding of how pyrolysis-FTIR can perform during sample triage on Mars. Key Words: Mars-Life-detection instruments-Search for Mars' organics-Biosignatures. Astrobiology 16, 831-845.

Vertically aligned carbon nanopillars with size and spacing control for a transparent field emission display.

PubMed

Lee, Seok Woo; Lee, Chang Hwa; Lee, Jung A; Lee, Seung S

2013-01-18

A top-down fabrication method is presented for vertically aligned carbon nanopillars (CNPs) using photolithography and pyrolysis. The modified backside exposure method of photolithography fabricates vertically aligned polymer (SU-8) nanopillars. The pyrolysis process, which transforms the polymer to amorphous carbon, reliably produces vertically aligned CNPs with widths ranging from 100 to 400 nm. The CNPs can be used as a transparent field emission cathode for a transparent display and light emission is observed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pendse, Hemant P.

Maine and its industries identified more efficient utilization of biomass as a critical economic development issue. In Phase I of this implementation project, a research team was assembled, research equipment was implemented and expertise was demonstrated in pyrolysis, hydrodeoxygenation of pyrolysis oils, catalyst synthesis and characterization, and reaction engineering. Phase II built upon the infrastructure to innovate reaction pathways and process engineering, and integrate new approaches for fuels and chemical production within pulp and paper and other industries within the state. This research cluster brought together chemists, engineers, physicists and students from the University of Maine, Bates College, and Bowdoinmore » College. The project developed collaborations with Oak Ridge National Laboratory and Brookhaven National Laboratory. The specific research projects within this proposal were of critical interest to the DoE - in particular the biomass program within EERE and the catalysis/chemical transformations program within BES. Scientific and Technical Merit highlights of this project included: (1) synthesis and physical characterization of novel size-selective catalyst/supports using engineered mesoporous (1-10 nm diameter pores) materials, (2) advances in fundamental knowledge of novel support/ metal catalyst systems tailored for pyrolysis oil upgrading, (3) a microcalorimetric sensing technique, (4) improved methods for pyrolysis oil characterization, (5) production and characterization of woody biomass-derived pyrolysis oils, (6) development of two new patented bio oil pathways: thermal deoxygenation (TDO) and formate assisted pyrolysis (FASP), and (7) technoeconomics of pyrolysis of Maine forest biomass. This research cluster has provided fundamental knowledge to enable and assess pathways to thermally convert biomass to hydrocarbon fuels and chemicals.« less

Characteristics of the microwave pyrolysis and microwave CO2-assisted gasification of dewatered sewage sludge.

PubMed

Chun, Young Nam; Jeong, Byeo Ri

2017-07-28

Microwave drying-pyrolysis or drying-gasification characteristics were examined to convert sewage sludge into energy and resources. The gasification was carried out with carbon dioxide as a gasifying agent. The examination results were compared with those of the conventional heating-type electric furnace to compare both product characteristics. Through the pyrolysis or gasification, gas, tar, and char were generated as products. The produced gas was the largest component of each process, followed by the sludge char and the tar. During the pyrolysis process, the main components of the produced gas were hydrogen and carbon monoxide, with a small amount of hydrocarbons such as methane and ethylene. In the gasification process, however, the amount of carbon monoxide was greater than the amount of hydrogen. In microwave gasification, a large amount of heavy tar was produced. The largest amount of benzene in light tar was generated from the pyrolysis or gasification. Ammonia and hydrogen cyanide, which are precursors of NO x , were also generated. In the microwave heating method, the sludge char produced by pyrolysis and gasification had pores in the mesopore range. This could be explained that the gas obtained from the microwave pyrolysis or gasification of the wet sewage sludge can be used as an alternative fuel, but the tar and NO x precursors in the produced gas should be treated. Sludge char can be used as a biomass solid fuel or as a tar removal adsorbent if necessary.

A Numerical Analysis of the Transient Response of an Ablation System Including Effects of Thermal Nonequilibrium, Mass Transfer and Chemical Kinetics. Ph.D Thesis - Virginia Polytechnic Inst. and State Univ.

NASA Technical Reports Server (NTRS)

Clark, R. K.

1972-01-01

The differential equations governing the transient response of a one-dimensional ablative thermal protection system undergoing stagnation ablation are derived. These equations are for thermal nonequilibrium effects between the pyrolysis gases and the char layer and kinetically controlled chemical reactions and mass transfer between the pyrolysis gases and the char layer. The boundary conditions are written for the particular case of stagnation heating with surface removal by oxidation or sublimation and pyrolysis of the uncharred layer occurring in a plane. The governing equations and boundary conditions are solved numerically using the modified implicit method (Crank-Nicolson method). Numerical results are compared with exact solutions for a number of simplified cases. The comparison is favorable in each instance.

Experimental study of thermal conductivity of pyrolysised materials by means of a flat layer

NASA Astrophysics Data System (ADS)

Vaniushkin, V. D.; Popov, S. K.; Sidenkov, D. V.

2017-11-01

Recycling of tires is currently a very important task. One of the areas of recycling tires is their low-temperature pyrolysis to produce marketable products - liquid fraction and a solid coke residue. For the development of the pyrolysis installation it is important to know the thermal conductivity of the coke residue at different temperatures of pyrolysis of initial material. As a property of matter, thermal conductivity depends in general on temperature and pressure. For materials with some structure, such as porous materials, the thermal conductivity depends on the characteristics of the structure. The thermal conductivity of the porous coke residue at pyrolysis temperatures of 300 0C, 400 0C, 500 0C and atmospheric pressure was studied experimentally at the laboratory unit of the department of “Theoretical basis of heat engineering” using the method of the flat layer in the temperature range 5…100 0C. Experimentally proved temperature dependencies of the coefficient of thermal conductivity of the coke residue are built to improve the accuracy of calculations of constructive and regime parameters of the pyrolysis installation.

Predicting properties of gas and solid streams by intrinsic kinetics of fast pyrolysis of wood

DOE PAGES

Klinger, Jordan; Bar-Ziv, Ezra; Shonnard, David; ...

2015-12-12

Pyrolysis has the potential to create a biocrude oil from biomass sources that can be used as fuel or as feedstock for subsequent upgrading to hydrocarbon fuels or other chemicals. The product distribution/composition, however, is linked to the biomass source. This work investigates the products formed from pyrolysis of woody biomass with a previously developed chemical kinetics model. Different woody feedstocks reported in prior literature are placed on a common basis (moisture, ash, fixed carbon free) and normalized by initial elemental composition through ultimate analysis. Observed product distributions over the full devolatilization range are explored, reconstructed by the model, andmore » verified with independent experimental data collected with a microwave-assisted pyrolysis system. These trends include production of permanent gas (CO, CO 2), char, and condensable (oil, water) species. Elementary compositions of these streams are also investigated. As a result, close agreement between literature data, model predictions, and independent experimental data indicate that the proposed model/method is able to predict the ideal distribution from fast pyrolysis given reaction temperature, residence time, and feedstock composition.« less

Confined-Pyrolysis as an Experimental Method for Hydrothermal Organic Synthesis

NASA Technical Reports Server (NTRS)

Leif, Roald N.; Simoneit, Bernd R. T.

1995-01-01

A closed pyrolysis system has been developed as a tool for studying the reactions of organic compounds under extreme hydrothermal conditions. Small high pressure stainless steel vessels in which the ratio of sediment or sample to water has been adjusted to eliminate the headspace at peak experimental conditions confines the organic components to the bulk solid matrix and eliminates the partitioning of the organic compounds away from the inorganic components during the experiment. Confined pyrolysis experiments were performed to simulate thermally driven catagenetic changes in sedimentary organic matter using a solids to water ratio of 3.4 to 1. The extent of alteration was measured by monitoring the steroid and triterpenoid biomarkers and polycyclic aromatic hydrocarbon distributions. These pyrolysis experiments duplicated the hydrothermal transformations observed in nature. Molecular probe experiments using alkadienes, alkenes and alkanes in H2O and D2O elucidated the isomerization and hydrogenation reactions of aliphatic and the competing oxidative reactions occurring under hydrothermal conditions. This confined pyrolysis technique is being applied to test experiments on organic synthesis of relevance to chemical evolution for the origin of life.

Kinetic and energy production analysis of pyrolysis of lignocellulosic biomass using a three-parallel Gaussian reaction model.

PubMed

Chen, Tianju; Zhang, Jinzhi; Wu, Jinhu

2016-07-01

The kinetic and energy productions of pyrolysis of a lignocellulosic biomass were investigated using a three-parallel Gaussian distribution method in this work. The pyrolysis experiment of the pine sawdust was performed using a thermogravimetric-mass spectroscopy (TG-MS) analyzer. A three-parallel Gaussian distributed activation energy model (DAEM)-reaction model was used to describe thermal decomposition behaviors of the three components, hemicellulose, cellulose and lignin. The first, second and third pseudocomponents represent the fractions of hemicellulose, cellulose and lignin, respectively. It was found that the model is capable of predicting the pyrolysis behavior of the pine sawdust. The activation energy distribution peaks for the three pseudo-components were centered at 186.8, 197.5 and 203.9kJmol(-1) for the pine sawdust, respectively. The evolution profiles of H2, CH4, CO, and CO2 were well predicted using the three-parallel Gaussian distribution model. In addition, the chemical composition of bio-oil was also obtained by pyrolysis-gas chromatography/mass spectrometry instrument (Py-GC/MS). Copyright © 2016 Elsevier Ltd. All rights reserved.

Catalytic fast co-pyrolysis of biomass and food waste to produce aromatics: Analytical Py-GC/MS study.

PubMed

Zhang, Bo; Zhong, Zhaoping; Min, Min; Ding, Kuan; Xie, Qinglong; Ruan, Roger

2015-01-01

In this study, catalytic fast co-pyrolysis (co-CFP) of corn stalk and food waste (FW) was carried out to produce aromatics using quantitative pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), and ZSM-5 zeolite in the hydrogen form was employed as the catalyst. Co-CFP temperature and a parameter called hydrogen to carbon effective ratio (H/C(eff) ratio) were examined for their effects on the relative content of aromatics. Experimental results showed that co-CFP temperature of 600 °C was optimal for the formation of aromatics and other organic pyrolysis products. Besides, H/C(eff) ratio had an important influence on product distribution. The yield of total organic pyrolysis products and relative content of aromatics increased non-linearly with increasing H/C(eff) ratio. There was an apparent synergistic effect between corn stalk and FW during co-CFP process, which promoted the production of aromatics significantly. Co-CFP of biomass and FW was an effective method to produce aromatics and other petrochemicals. Copyright © 2015. Published by Elsevier Ltd.

Co-production of furfural and acetic acid from corncob using ZnCl2 through fast pyrolysis in a fluidized bed reactor.

PubMed

Oh, Seung-Jin; Jung, Su-Hwa; Kim, Joo-Sik

2013-09-01

Corncob was pyrolyzed using ZnCl2 in a pyrolysis plant equipped with a fluidized bed reactor to co-produce furfural and acetic acid. The effects of reaction conditions, the ZnCl2 content and contacting method of ZnCl2 with corncob on the yields of furfural and acetic acid were investigated. The pyrolysis was performed within the temperature range between 310 and 410°C, and the bio-oil yield were 30-60 wt% of the product. The furfural yield increased up to 8.2 wt%. The acetic acid yield was maximized with a value of 13.1 wt%. A lower feed rate in the presence of ZnCl2 was advantageous for the production of acetic acid. The fast pyrolysis of a smaller corncob sample mechanically mixed with 20 wt% of ZnCl2 gave rise to a distinct increase in furfural. A high selectivity for furfural and acetic acid in bio-oil would make the pyrolysis of corncob with ZnCl2 very economically attractive. Copyright © 2013 Elsevier Ltd. All rights reserved.

Spatial distribution visualization of PWM continuous variable-rate spray

USDA-ARS?s Scientific Manuscript database

Chemical application is a dynamic spatial distribution process, during which spray liquid covers the targets with certain thickness and uniformity. Therefore, it is important to study the 2-D and 3-D (dimensional) spray distribution to evaluate spraying quality. The curve-surface generation methods ...

Pyrolysis of wastewater sludge and composted organic fines from municipal solid waste: laboratory reactor characterisation and product distribution.

PubMed

Agar, David A; Kwapinska, Marzena; Leahy, James J

2018-02-26

Sludge from municipal wastewater treatment plants and organic fines from mechanical sorting of municipal solid waste (MSW) are two common widespread waste streams that are becoming increasingly difficult to utilise. Changing perceptions of risk in food production has limited the appeal of sludge use on agricultural land, and outlets via landfilling are diminishing rapidly. These factors have led to interest in thermal conversion technologies whose aim is to recover energy and nutrients from waste while reducing health and environmental risks associated with material re-use. Pyrolysis yields three output products: solid char, liquid oils and gas. Their relative distribution depends on process parameters which can be somewhat optimised depending on the end use of product. The potential of pyrolysis for the conversion of wastewater sludge (SS) and organic fines of MSW (OF) to a combustion gas and a carbon-rich char has been investigated. Pyrolysis of SS and OF was done using a laboratory fixed-bed reactor. Herein, the physical characterisation of the reactor is described, and results on pyrolysis yields are presented. Feedstock and chars have been characterised using standard laboratory methods, and the composition of pyrolysis gases was analysed using micro gas chromatography. Product distribution (char/liquid/gas) from the pyrolysis of sewage sludge and composted MSW fines at 700°C for 10 min were 45/26/29 and 53/14/33%, respectively. The combustible fractions of pyrolysis gases range from 36 to 54% for SS feedstock and 62 to 72% from OF. The corresponding lower heating value range of sampled gases were 11.8-19.1 and 18.2-21.0 MJ m -3 , respectively.

Successful scaling-up of self-sustained pyrolysis of oil palm biomass under pool-type reactor.

PubMed

Idris, Juferi; Shirai, Yoshihito; Andou, Yoshito; Mohd Ali, Ahmad Amiruddin; Othman, Mohd Ridzuan; Ibrahim, Izzudin; Yamamoto, Akio; Yasuda, Nobuhiko; Hassan, Mohd Ali

2016-02-01

An appropriate technology for waste utilisation, especially for a large amount of abundant pressed-shredded oil palm empty fruit bunch (OFEFB), is important for the oil palm industry. Self-sustained pyrolysis, whereby oil palm biomass was combusted by itself to provide the heat for pyrolysis without an electrical heater, is more preferable owing to its simplicity, ease of operation and low energy requirement. In this study, biochar production under self-sustained pyrolysis of oil palm biomass in the form of oil palm empty fruit bunch was tested in a 3-t large-scale pool-type reactor. During the pyrolysis process, the biomass was loaded layer by layer when the smoke appeared on the top, to minimise the entrance of oxygen. This method had significantly increased the yield of biochar. In our previous report, we have tested on a 30-kg pilot-scale capacity under self-sustained pyrolysis and found that the higher heating value (HHV) obtained was 22.6-24.7 MJ kg(-1) with a 23.5%-25.0% yield. In this scaled-up study, a 3-t large-scale procedure produced HHV of 22.0-24.3 MJ kg(-1) with a 30%-34% yield based on a wet-weight basis. The maximum self-sustained pyrolysis temperature for the large-scale procedure can reach between 600 °C and 700 °C. We concluded that large-scale biochar production under self-sustained pyrolysis was successfully conducted owing to the comparable biochar produced, compared with medium-scale and other studies with an electrical heating element, making it an appropriate technology for waste utilisation, particularly for the oil palm industry. © The Author(s) 2015.

Light extinction method on high-pressure diesel injection

NASA Astrophysics Data System (ADS)

Su, Tzay-Fa; El-Beshbeeshy, Mahmound S.; Corradini, Michael L.; Farrell, Patrick V.

1995-09-01

A two dimensional optical diagnostic technique based on light extinction was improved and demonstrated in an investigation of diesel spray characteristics at high injection pressures. Traditional light extinction methods require the spray image to be perpendicular to the light path. In the improved light extinction scheme, a tilted spray image which has an angle with the light path is still capable of being processed. This technique utilizes high speed photography and digital image analysis to obtain qualitative and quantitative information of the spray characteristics. The injection system used was an electronically controlled common rail unit injector system with injection pressures up to 100 MPa. The nozzle of the injector was a mini-sac type with six holes on the nozzle tip. Two different injection angle nozzles, 125 degree(s) and 140 degree(s), producing an in-plane tilted spray and an out of plane tilted spray were investigated. The experiments were conducted on a constant volume spray chamber with the injector mounted tilted at an angle of 62.5 degree(s)$. Only one spray plume was viewed, and other sprays were free to inject to the chamber. The spray chamber was pressurized with argon and air under room temperature to match the combustion chamber density at the start of the injection. The experimental results show that the difference in the spray tip penetration length, spray angle, and overall average Sauter mean diameter is small between the in- plane tilted spray and the out of plane tilted spray. The results also show that in-plane tilted spray has a slightly larger axial cross- section Sauter mean diameter than the out of plane tilted spray.

A Validation Summary of the NCC Turbulent Reacting/non-reacting Spray Computations

NASA Technical Reports Server (NTRS)

Raju, M. S.; Liu, N.-S. (Technical Monitor)

2000-01-01

This pper provides a validation summary of the spray computations performed as a part of the NCC (National Combustion Code) development activity. NCC is being developed with the aim of advancing the current prediction tools used in the design of advanced technology combustors based on the multidimensional computational methods. The solution procedure combines the novelty of the application of the scalar Monte Carlo PDF (Probability Density Function) method to the modeling of turbulent spray flames with the ability to perform the computations on unstructured grids with parallel computing. The calculation procedure was applied to predict the flow properties of three different spray cases. One is a nonswirling unconfined reacting spray, the second is a nonswirling unconfined nonreacting spray, and the third is a confined swirl-stabilized spray flame. The comparisons involving both gas-phase and droplet velocities, droplet size distributions, and gas-phase temperatures show reasonable agreement with the available experimental data. The comparisons involve both the results obtained from the use of the Monte Carlo PDF method as well as those obtained from the conventional computational fluid dynamics (CFD) solution. Detailed comparisons in the case of a reacting nonswirling spray clearly highlight the importance of chemistry/turbulence interactions in the modeling of reacting sprays. The results from the PDF and non-PDF methods were found to be markedly different and the PDF solution is closer to the reported experimental data. The PDF computations predict that most of the combustion occurs in a predominantly diffusion-flame environment. However, the non-PDF solution predicts incorrectly that the combustion occurs in a predominantly vaporization-controlled regime. The Monte Carlo temperature distribution shows that the functional form of the PDF for the temperature fluctuations varies substantially from point to point. The results also bring to the fore some of the deficiencies associated with the use of assumed-shape PDF methods in spray computations.

Pyrolysis of automotive shredder residue in a bench scale rotary kiln.

PubMed

Notarnicola, Michele; Cornacchia, Giacinto; De Gisi, Sabino; Di Canio, Francesco; Freda, Cesare; Garzone, Pietro; Martino, Maria; Valerio, Vito; Villone, Antonio

2017-07-01

Automotive shredder residue (ASR) can create difficulties when managing, with its production increasing. It is made of different type of plastics, foams, elastomers, wood, glasses and textiles. For this reason, it is complicated to dispose of in a cost effective way, while also respecting the stringent environmental restrictions. Among thermal treatments, pyrolysis seems to offer an environmentally attractive method for the treatment of ASR; it also allows for the recovery of valuable secondary materials/fuels such as pyrolysis oils, chars, and gas. While, there is a great deal of significant research on ASR pyrolysis, the literature on higher scale pyrolysis experiments is limited. To improve current literature, the aim of the study was to investigate the pyrolysis of ASR in a bench scale rotary kiln. The Italian ASR was separated by dry-sieving into two particle size fractions: d<30mm and d>30mm. Both the streams were grounded, pelletized and then pyrolyzed in a continuous bench scale rotary kiln at 450, 550 and 650°C. The mass flow rate of the ASR pellets was 200-350g/h and each test ran for about 4-5h. The produced char, pyrolysis oil and syngas were quantified to determine product distribution. They were thoroughly analyzed with regard to their chemical and physical properties. The results show how higher temperatures increase the pyrolysis gas yield (44wt% at 650°C) as well as its heating value. The low heating value (LHV) of syngas ranges between 18 and 26MJ/Nm 3 dry. The highest pyrolysis oil yield (33wt.%) was observed at 550°C and its LHV ranges between 12.5 and 14.5MJ/kg. Furthermore, only two out of the six produced chars respect the LHV limit set by the Italian environmental regulations for landfilling. The obtained results in terms of product distribution and their chemical-physical analyses provide useful information for plant scale-up. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spray Drift Reduction Evaluations of Spray Nozzles Using a Standardized Testing Protocol

DTIC Science & Technology

2010-07-01

Drop Size Characteristics in a Spray Using Optical Nonimaging Light-Scattering Instruments,” Annual Book of ASTM Standards, Vol. 14-02, ASTM...Test Method for Determining Liquid Drop Size Characteristics in a Spray Using Optical Non- imaging Light-Scattering Instruments 22. AGDISP Model

Well-to-wheels analysis of fast pyrolysis pathways with the GREET model.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, J.; Elgowainy, A.; Palou-Rivera, I.

The pyrolysis of biomass can help produce liquid transportation fuels with properties similar to those of petroleum gasoline and diesel fuel. Argonne National Laboratory conducted a life-cycle (i.e., well-to-wheels [WTW]) analysis of various pyrolysis pathways by expanding and employing the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model. The WTW energy use and greenhouse gas (GHG) emissions from the pyrolysis pathways were compared with those from the baseline petroleum gasoline and diesel pathways. Various pyrolysis pathway scenarios with a wide variety of possible hydrogen sources, liquid fuel yields, and co-product application and treatment methods were considered. Atmore » one extreme, when hydrogen is produced from natural gas and when bio-char is used for process energy needs, the pyrolysis-based liquid fuel yield is high (32% of the dry mass of biomass input). The reductions in WTW fossil energy use and GHG emissions relative to those that occur when baseline petroleum fuels are used, however, is modest, at 50% and 51%, respectively, on a per unit of fuel energy basis. At the other extreme, when hydrogen is produced internally via reforming of pyrolysis oil and when bio-char is sequestered in soil applications, the pyrolysis-based liquid fuel yield is low (15% of the dry mass of biomass input), but the reductions in WTW fossil energy use and GHG emissions are large, at 79% and 96%, respectively, relative to those that occur when baseline petroleum fuels are used. The petroleum energy use in all scenarios was restricted to biomass collection and transportation activities, which resulted in a reduction in WTW petroleum energy use of 92-95% relative to that found when baseline petroleum fuels are used. Internal hydrogen production (i.e., via reforming of pyrolysis oil) significantly reduces fossil fuel use and GHG emissions because the hydrogen from fuel gas or pyrolysis oil (renewable sources) displaces that from fossil fuel natural gas and the amount of fossil natural gas used for hydrogen production is reduced; however, internal hydrogen production also reduces the potential petroleum energy savings (per unit of biomass input basis) because the fuel yield declines dramatically. Typically, a process that has a greater liquid fuel yield results in larger petroleum savings per unit of biomass input but a smaller reduction in life-cycle GHG emissions. Sequestration of the large amount of bio-char co-product (e.g., in soil applications) provides a significant carbon dioxide credit, while electricity generation from bio-char combustion provides a large energy credit. The WTW energy and GHG emissions benefits observed when a pyrolysis oil refinery was integrated with a pyrolysis reactor were small when compared with those that occur when pyrolysis oil is distributed to a distant refinery, since the activities associated with transporting the oil between the pyrolysis reactors and refineries have a smaller energy and emissions footprint than do other activities in the pyrolysis pathway.« less

One-Dimensional Ablation with Pyrolysis Gas Flow Using a Full Newton's Method and Finite Control Volume Procedure

NASA Technical Reports Server (NTRS)

Amar, Adam J.; Blackwell, Ben F.; Edwards, Jack R.

2007-01-01

The development and verification of a one-dimensional material thermal response code with ablation is presented. The implicit time integrator, control volume finite element spatial discretization, and Newton's method for nonlinear iteration on the entire system of residual equations have been implemented and verified for the thermochemical ablation of internally decomposing materials. This study is a continuation of the work presented in "One-Dimensional Ablation with Pyrolysis Gas Flow Using a Full Newton's Method and Finite Control Volume Procedure" (AIAA-2006-2910), which described the derivation, implementation, and verification of the constant density solid energy equation terms and boundary conditions. The present study extends the model to decomposing materials including decomposition kinetics, pyrolysis gas flow through the porous char layer, and a mixture (solid and gas) energy equation. Verification results are presented for the thermochemical ablation of a carbon-phenolic ablator which involves the solution of the entire system of governing equations.

Integrated coke, asphalt and jet fuel production process and apparatus

DOEpatents

Shang, Jer Y.

1991-01-01

A process and apparatus for the production of coke, asphalt and jet fuel m a feed of fossil fuels containing volatile carbon compounds therein is disclosed. The process includes the steps of pyrolyzing the feed in an entrained bed pyrolyzing means, separating the volatile pyrolysis products from the solid pyrolysis products removing at least one coke from the solid pyrolysis products, fractionating the volatile pyrolysis products to produce an overhead stream and a bottom stream which is useful as asphalt for road pavement, condensing the overhead stream to produce a condensed liquid fraction and a noncondensable, gaseous fraction, and removing water from the condensed liquid fraction to produce a jet fuel-containing product. The disclosed apparatus is useful for practicing the foregoing process. the process provides a useful method of mass producing and jet fuels from materials such as coal, oil shale and tar sands.

Comparative study on the pyrolysis behaviour and kinetics of two macroalgae biomass (Gracilaria changii and Gelidium pusillum) by thermogravimetric analysis

NASA Astrophysics Data System (ADS)

Roslee, A. N.; Munajat, N. F.

2017-10-01

Macroalgae are often referred as seaweed and could be significant biomass resource for the production of numerous energy carriers including biofuels. In this study, the chemical composition of Gracilaria changii (G. changii) and Gelidium pusillum (G. pusillum) were determined through proximate and ultimate analysis and the thermal degradation behaviour of G. changii and G. pusillum were investigated via thermogravimetric analysis (TGA) in determining the important main composition to be considered as biomass fuels. It has found the pyrolysis of G. changii and G. pusillum consists of three stages and stage II is the main decomposition stage with major mass loss of around 52.16% and 44.42%, respectively. The TGA data were then used for determination of kinetic parameters of the pyrolysis process using three model-free methods: Kissinger, Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO). The apparent activation energy calculated by using Kissinger method for G. changii was lower than G. Pusillum, i.e.173.12 kJ/mol and 193.22 kJ/mol, respectively. The activation energies calculated from KAS and FWO methods were increased with increasing the pyrolysis conversion with average activation energies of 172.32 kJ/mol and 181.19 kJ/mol for G. changii while for G. pusillum (177.42 kJ/mol and 187.4 kJ/mol). G. pusillum has lower and wider distribution of activation energy and revealed that the pyrolysis process for G. changii was easier than G. pusillum. These data provide information for further application for designing and modelling in thermochemical conversion system of macroalgae biomass.

Co-pyrolysis characteristics of microalgae Isochrysis and Chlorella: Kinetics, biocrude yield and interaction.

PubMed

Zhao, Bingwei; Wang, Xin; Yang, Xiaoyi

2015-12-01

Co-pyrolysis characteristics of Isochrysis (high lipid) and Chlorella (high protein) were investigated qualitatively and quantitatively based on DTG curves, biocrude yield and composition by individual pyrolysis and co-pyrolysis. DTG curves in co-pyrolysis have been compared accurately with those in individual pyrolysis. An interaction has been detected at 475-500°C in co-pyrolysis based on biocrude yields, and co-pyrolysis reaction mechanism appear three-dimensional diffusion in comparison with random nucleation followed by growth in individual pyrolysis based on kinetic analysis. There is no obvious difference in the maximum biocrude yields for individual pyrolysis and co-pyrolysis, but carboxylic acids (IC21) decreased and N-heterocyclic compounds (IC12) increased in co-pyrolysis. Simulation results of biocrude yield by Components Biofuel Model and Kinetics Biofuel Model indicate that the processes of co-pyrolysis comply with those of individual pyrolysis in solid phase by and large. Variation of percentage content in co-pyrolysis and individual pyrolysis biocrude indicated interaction in gas phase. Copyright © 2015. Published by Elsevier Ltd.

Method for making carbon super capacitor electrode materials

DOEpatents

Firsich, D.W.; Ingersoll, D.; Delnick, F.M.

1998-07-07

A method is described for making near-net-shape, monolithic carbon electrodes for energy storage devices. The method includes the controlled pyrolysis and activation of a pressed shape of methyl cellulose powder with pyrolysis being carried out in two stages; pre-oxidation, preferably in air at a temperature between 200--250 C, followed by carbonization under an inert atmosphere. An activation step to adjust the surface area of the carbon shape to a value desirable for the application being considered, including heating the carbon shape in an oxidizing atmosphere to a temperature of at least 300 C, follows carbonization. 1 fig.

Method for making carbon super capacitor electrode materials

DOEpatents

Firsich, David W.; Ingersoll, David; Delnick, Frank M.

1998-01-01

A method for making near-net-shape, monolithic carbon electrodes for energy storage devices. The method includes the controlled pyrolysis and activation of a pressed shape of methyl cellulose powder with pyrolysis being carried out in two stages; pre-oxidation, preferably in air at a temperature between 200.degree.-250.degree. C., followed by carbonization under an inert atmosphere. An activation step to adjust the surface area of the carbon shape to a value desirable for the application being considered, including heating the carbon shape in an oxidizing atmosphere to a temperature of at least 300.degree. C., follows carbonization.

Thermal Spray Maps: Material Genomics of Processing Technologies

NASA Astrophysics Data System (ADS)

Ang, Andrew Siao Ming; Sanpo, Noppakun; Sesso, Mitchell L.; Kim, Sun Yung; Berndt, Christopher C.

2013-10-01

There is currently no method whereby material properties of thermal spray coatings may be predicted from fundamental processing inputs such as temperature-velocity correlations. The first step in such an important understanding would involve establishing a foundation that consolidates the thermal spray literature so that known relationships could be documented and any trends identified. This paper presents a method to classify and reorder thermal spray data so that relationships and correlations between competing processes and materials can be identified. Extensive data mining of published experimental work was performed to create thermal spray property-performance maps, known as "TS maps" in this work. Six TS maps will be presented. The maps are based on coating characteristics of major importance; i.e., porosity, microhardness, adhesion strength, and the elastic modulus of thermal spray coatings.

Assessment of nasal spray deposition pattern in a silicone human nose model using a color-based method.

PubMed

Kundoor, Vipra; Dalby, Richard N

2010-01-01

To develop a simple and inexpensive method to visualize and quantify droplet deposition patterns. Deposition pattern was determined by uniformly coating the nose model with Sar-Gel (a paste that changes from white to purple on contact with water) and subsequently discharging sprays into the nose model. The color change was captured using a digital camera and analyzed using Adobe Photoshop. Several tests were conducted to validate the method. Deposition patterns of different nasal sprays (Ayr, Afrin, and Zicam) and different nasal drug delivery devices (Afrin nasal spray and PARI Sinustar nasal nebulizer) were compared. We also used the method to evaluate the effect of inhaled flow rate on nasal spray deposition. There was a significant difference in the deposition area for Ayr, Afrin, and Zicam. The deposition areas of Afrin nasal spray and PARI Sinustar nasal nebulizer (2 min and 5 min) were significantly different. Inhaled flow rate did not have a significant effect on the deposition pattern. Lower viscosity formulations (Ayr, Afrin) provided greater coverage than the higher viscosity formulation (Zicam). The nebulizer covered a greater surface area than the spray pump we evaluated. Aerosol deposition in the nose model was not affected by air flow conditions.

Further Evaluation of Spray Characterization of Sprayers Typically Used in Vector Control

DTIC Science & Technology

2012-01-01

E1260. Standard test method for determining liquid drop size characteristics in a spray using optical nonimaging light-scattering instru- ments...The time that the spray cloud was directed through the optical path of the laser varied between sprayers depending on the width of the spray plume

Optimization of Fibrin Glue Spray Systems for Ophthalmic Surgery

PubMed Central

Chaurasia, Shyam S.; Champakalakshmi, Ravi; Angunawela, Romesh I.; Tan, Donald T.; Mehta, Jodhbir S.

2012-01-01

Purpose To optimize fibrin glue (FG) spray for ophthalmic surgery using two spray applicators, EasySpray and DuploSpray systems, by varying the distance from point of application and the pressure/flow rate, and to compare the adhesive strength of sutured and sutureless (FG sprayed) conjunctival graft surgery in a rabbit model. Methods FG was sprayed on a 0.2 mm-thick sheet of paper using EasySpray by variously combining application distances of 2.5, 5, 7.5, and 10 cm with pressures of 10, 15, and 20 psi. DuploSpray was used at the same distances but with varying flow rates of 1 and 2 L/min. Subsequently, FG was sprayed on porcine corneas and FG thickness was analyzed by histology. In addition, adhesive strength of the conjunctival graft (0.5 × 0.5 cm) attached to the rabbit cornea by sutured and sutureless surgery (FG spray) was compared using a tension meter. Results Histology measurements revealed that the FG thickness decreased with increases in distance and pressure of spray using the EasySpray applicator on paper and porcine corneal sections. The adhesive strength of the sutured conjunctival graft (41 ± 4.85 [kilopascal] KPa) was found to be higher than the graft attached by spraying (10 ± 2.3 KPa) and the sequential addition of FG (6 ± 0.714 KPa). Conclusions The EasySpray applicator formed a uniform spread of FG at a distance-pressure combination of 5 cm and 20 psi. The conjunctival graft attached with sutures had higher adhesive strength compared with grafts glued with a spray applicator. Although the adhesive strength of FG applied through the applicator was similar to the drop-wise sequential technique, the former was more cost effective because more samples could be sprayed compared with the sequential manual technique. Translational Relevance The standardization of the spray system for the application of FG in ophthalmology will provide an economical method for delivering consistent healing results after surgery. PMID:24049702

Origin of carbon in aromatic and olefin products derived from HZSM-5 catalyzed co-pyrolysis of cellulose and plastics via isotopic labeling

USDA-ARS?s Scientific Manuscript database

Catalytic pyrolysis over HZSM-5 is an effective method for the conversion of biomass to aromatic hydrocarbons, albeit with low yield and short catalyst lifetimes. Addition of co-reactants rich in carbon and hydrogen can enhance yield and possibly increase catalyst lifetimes by reducing coke formati...

Rapid detection of bacteria with miniaturized pyrolysis-gas chromatographic analysis

NASA Astrophysics Data System (ADS)

Mowry, Curtis; Morgan, Catherine H.; Baca, Quentin; Manginell, Ronald P.; Kottenstette, Richard J.; Lewis, Patrick; Frye-Mason, Gregory C.

2002-02-01

Rapid detection and identification of bacteria and other pathogens is important for many civilian and military applications. The profiles of biological markers such as fatty acids can be used to characterize biological samples or to distinguish bacteria at the gram-type, genera, and even species level. Common methods for whole cell bacterial analysis are neither portable nor rapid, requiring lengthy, labor intensive sample preparation and bench-scale instrumentation. These methods chemically derivatize fatty acids to produce more volatile fatty acid methyl esters (FAMEs) that can be separated and analyzed by a gas chromatograph (GC)/mass spectrometer. More recent publications demonstrate decreased sample preparation time with in situ derivatization of whole bacterial samples using pyrolysis/derivatization. Ongoing development of miniaturized pyrolysis/GC instrumentation by this department capitalizes on Sandia advances in the field of microfabricated chemical analysis systems ((mu) ChemLab). Microdevices include rapidly heated stages capable of pyrolysis or sample concentration, gas chromatography columns, and surface acoustic wave (SAW) sensor arrays. We will present results demonstrating the capabilities of these devices toward fulfilling the goal of portable, rapid detection and early warning of the presence of pathogens in air or water.

Use of a Deuterated Internal Standard with Pyrolysis-GC/MS Dimeric Marker Analysis to Quantify Tire Tread Particles in the Environment

PubMed Central

Unice, Kenneth M.; Kreider, Marisa L.; Panko, Julie M.

2012-01-01

Pyrolysis(pyr)-GC/MS analysis of characteristic thermal decomposition fragments has been previously used for qualitative fingerprinting of organic sources in environmental samples. A quantitative pyr-GC/MS method based on characteristic tire polymer pyrolysis products was developed for tread particle quantification in environmental matrices including soil, sediment, and air. The feasibility of quantitative pyr-GC/MS analysis of tread was confirmed in a method evaluation study using artificial soil spiked with known amounts of cryogenically generated tread. Tread concentration determined by blinded analyses was highly correlated (r2 ≥ 0.88) with the known tread spike concentration. Two critical refinements to the initial pyrolysis protocol were identified including use of an internal standard and quantification by the dimeric markers vinylcyclohexene and dipentene, which have good specificity for rubber polymer with no other appreciable environmental sources. A novel use of deuterated internal standards of similar polymeric structure was developed to correct the variable analyte recovery caused by sample size, matrix effects, and ion source variability. The resultant quantitative pyr-GC/MS protocol is reliable and transferable between laboratories. PMID:23202830

Sustainable options for the utilization of solid residues from wine production.

PubMed

Zhang, Nansen; Hoadley, Andrew; Patel, Jim; Lim, Seng; Li, Chao'en

2017-02-01

The efficient use of solid organic waste materials is an issue of particular importance for the wine industry. This paper focuses on the valorization of grape marc, the major component of winery organic waste (60-70%). Two methods were designed and compared: combustion to generate electricity, and the pyrolysis for the production of bio-char, bio-oil, and bio-gas. Each of these processes was analysed to determine their economic and environmental viability. The flow-sheeting software, ASPEN PLUS, was used to model the two cases. Data from the simulations was used to inform techno-economic and environmental analyses. Pyrolysis was found to be the superior method of utilizing grape marc from both economic and environmental perspectives. Both pyrolysis and combustion exploit the energy content of the waste, which is not recovered by the traditional treatments, composting or distillation. In addition to the production of energy, pyrolysis yielded 151kg of bio-char and 140kg of bio-oil per tonne of grape marc. These products may be used in place of fossil fuels, resulting in a net reduction of carbon dioxide emissions. However, the potential deleterious effects resulting from the replacement of the traditional treatments was not considered. Investment in either pyrolysis or combustion had a negligible impact on the price of the wine produced for wineries with an annual grape crush larger than 1000 tonnes. Composting has significant economic advantages in wineries with a small grape crush of less than 50 tonnes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Homogeneous Iron Phosphate Nanoparticles by Combustion of Sprays

PubMed Central

Rudin, Thomas; Pratsinis, Sotiris E.

2013-01-01

Low-cost synthesis of iron phosphate nanostructured particles is attractive for large scale fortification of basic foods (rice, bread, etc.) as well as for Li-battery materials. This is achieved here by flame-assisted and flame spray pyrolysis (FASP and FSP) of inexpensive precursors (iron nitrate, phosphate), solvents (ethanol), and support gases (acetylene and methane). The iron phosphate powders produced here were mostly amorphous and exhibited excellent solubility in dilute acid, an indicator of relative iron bioavailability. The amorphous and crystalline fractions of such powders were determined by X-ray diffraction (XRD) and their cumulative size distribution by X-ray disk centrifuge. Fine and coarse size fractions were obtained also by sedimentation and characterized by microscopy and XRD. The coarse size fraction contained maghemite Fe2O3 while the fine was amorphous iron phosphate. Furthermore, the effect of increased production rate (up to 11 g/h) on product morphology and solubility was explored. Using increased methane flow rates through the ignition/pilot flame of the FSP-burner and inexpensive powder precursors resulted in also homogeneous iron phosphate nanoparticles essentially converting the FSP to a FASP process. The powders produced by FSP at increased methane flow had excellent solubility in dilute acid as well. Such use of methane or even natural gas might be economically attractive for large scale flame-synthesis of nanoparticles. PMID:23407874

Room temperature magnetization in Co-doped anatase phase of TiO2

NASA Astrophysics Data System (ADS)

Karimipour, Masoud; Mageto, Maxwel Joel; Etefagh, Reyhaneh; Azhir, Elahe; Mwamburi, Mghendi; Topalian, Zareh

2013-01-01

CoxTi1-xO2 films were deposited by spray pyrolysis technique on Si(1 0 0) substrates at 475 °C. A hydro-alcoholic solution containing titanium (iv) isopropoxide and Co(NO3)2 with various Co doping levels from x = 0-0.015 in solution was used as spray solution. Grazing incident angle of X-ray diffraction illustrates that the CoxTi1-xO2 films are single phase and polycrystal with mixed orientations. Study of surface morphology of the films by atomic force microscope reveals that the annealing atmosphere does not significantly affect the grain size and the microstructure of the films. This study provides further insight into the importance of annealing atmosphere on magnetization of the films. Room temperature magneto-optical Kerr measurement was employed in polar mode. A hysteresis loop and a paramagnetic behavior have been recorded for samples annealed in H2 ambient gas and air, respectively. Chemical composition analysis by X-ray photo-electron spectroscopy showed that Co atoms are bounded to oxygen and no metallic clusters are present. Moreover, it indicates the formation of high spin Co2+ for the sample x = 0.008 annealed in H2 ambient gas. The origin of magnetization can be attributed to the contribution of oxygen vacancies in the spin polarization of the structure.

Synthesis and characterization of spray deposited CZTS thin films for photo-electrochemical application

NASA Astrophysics Data System (ADS)

Chavda, Arvind; Patel, Biren; Mukhopadhyay, Priyanka Marathey Indrajit; Ray, Abhijit

2018-05-01

Cu2ZnSnS4 (CZTS) is one of the most promising light absorber materials for photovoltaic and photo-electrochemical applications. We synthesized CZTS thin films on a F:SnO2 and soda lime glass substrates by very simple, cost effective and highly scalable spray pyrolysis technique. The films were post treated by rapid thermal processing route of sulfurization to enhance the stoichiometry and crystallinity of the film. The structural, morphological, optical and electrical properties of RTP sulfurized films were studied. The X-ray diffraction (XRD) pattern revealed the formation of tetragonal CZTS phase, which confirmed by Raman analysis with a major peak at 336 cm-1 without the presence of the principle vibration mode of any other secondary phases, such as Cu2SnS3, CuxS(x=1.8,2) etc. The sulfurized film exhibited increased crystallinity and better stoichiometry. The optical and electrical data reveal the direct optical band gap, bulk carrier concentration and resistivity of 1.5 eV, 2.28×1018 cm-3 and 1.21 Ω/cm2, respectively. Finally the photoactivity of CZTS thin films was tested by forming photoelectrochemical cell in 0.1M Na2S2O3 electrolyte (pH=7.72), showing a cathodic photocurrent of nearly 20 µA/cm2 at 0V RHE.

Sensing Characteristics of Flame-Spray-Made Pt/ZnO Thick Films as H2 Gas Sensor

PubMed Central

Tamaekong, Nittaya; Liewhiran, Chaikarn; Wisitsoraat, Anurat; Phanichphant, Sukon

2009-01-01

Hydrogen sensing of thick films of nanoparticles of pristine, 0.2, 1.0 and 2.0 atomic percentage of Pt concentration doped ZnO were investigated. ZnO nanoparticles doped with 0.2–2.0 at.% Pt were successfully produced in a single step by flame spray pyrolysis (FSP) technique using zinc naphthenate and platinum(II) acetylacetonate as precursors dissolved in xylene. The particle properties were analyzed by XRD, BET, SEM and TEM. Under the 5/5 (precursor/oxygen) flame condition, ZnO nanoparticles and nanorods were observed. The crystallite sizes of ZnO spheroidal and hexagonal particles were found to be ranging from 5 to 20 nm while ZnO nanorods were seen to be 5–20 nm wide and 20–40 nm long. ZnO nanoparticles paste composed of ethyl cellulose and terpineol as binder and solvent respectively was coated on Al2O3 substrate interdigitated with gold electrodes to form thin films by spin coating technique. The thin film morphology was analyzed by SEM technique. The gas sensing properties toward hydrogen (H2) was found that the 0.2 at.% Pt/ZnO sensing film showed an optimum H2 sensitivity of ∼164 at hydrogen concentration in air of 1 volume% at 300 °C and a low hydrogen detection limit of 50 ppm at 300 °C operating temperature. PMID:22399971

Fundamental modeling of pulverized coal and coal-water slurry combustion in a gas turbine combustor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chatwani, A.; Turan, A.; Hals, F.

1988-01-01

This work describes the essential features of a coal combustion model which is incorporated into a three-dimensional, steady-state, two-phase, turbulent, reactive flow code. The code is a modified and advanced version of INTERN code originally developed at Imperial College which has gone through many stages of development and validation. Swithenbank et al have reported spray combustion model results for an experimental can combustor. The code has since then been modified by and made public under a US Army program. A number of code modifications and improvements have been made at ARL. The earlier version of code was written for amore » small CDC machine which relied on frequent disk/memory transfer and overlay features to carry the computations resulting in loss of computational speed. These limitations have now been removed. For spray applications, the fuel droplet vaporization generates gaseous fuel of uniform composition; hence the earlier formulation relied upon the use of conserved scalar approximation to reduce the number of species equations to be solved. In applications related to coal fuel, coal pyrolysis leads to the formation of at least two different gaseous fuels and a solid fuel of different composition. The authors have therefore removed the conserved scalar formulation for the sake of generality and easy adaptability to complex fuel situations.« less

Formation of Indium-Doped Zinc Oxide Thin Films Using Ultrasonic Spray Pyrolysis: The Importance of the Water Content in the Aerosol Solution and the Substrate Temperature for Enhancing Electrical Transport.

PubMed

Biswal, Rajesh; Castañeda, Luis; Moctezuma, Rosario; Vega-Pérez, Jaime; Olvera, María De La Luz; Maldonado, Arturo

2012-03-12

Indium doped zinc oxide [ZnO:In] thin films have been deposited at 430°C on soda-lime glass substrates by the chemical spray technique, starting from zinc acetate and indium acetate. Pulverization of the solution was done by ultrasonic excitation. The variations in the electrical, structural, optical, and morphological characteristics of ZnO:In thin films, as a function of both the water content in the starting solution and the substrate temperature, were studied. The electrical resistivity of ZnO:In thin films is not significantly affected with the increase in the water content, up to 200 mL/L; further increase in water content causes an increase in the resistivity of the films. All films show a polycrystalline character, fitting well with the hexagonal ZnO wurtzite-type structure. No preferential growth in samples deposited with the lowest water content was observed, whereas an increase in water content gave rise to a (002) growth. The surface morphology of the films shows a consistency with structure results, as non-geometrical shaped round grains were observed in the case of films deposited with the lowest water content, whereas hexagonal slices, with a wide size distribution were observed in the other cases. In addition, films deposited with the highest water content show a narrow size distribution.

Spray method for recovery of heat-injured Salmonella Typhimurium and Listeria monocytogenes.

PubMed

Back, Kyeong-Hwan; Kim, Sang-Oh; Park, Ki-Hwan; Chung, Myung-Sub; Kang, Dong-Hyun

2012-10-01

Selective agar is inadequate for supporting recovery of injured cells. During risk assessment of certain foods, both injured and noninjured cells must be enumerated. In this study, a new method (agar spray method) for recovering sublethally heat-injured microorganisms was developed and used for recovery of heat-injured Salmonella Typhimurium and Listeria monocytogenes. Molten selective agar was applied as an overlay to presolidified nonselective tryptic soy agar (TSA) by spray application. Heat-injured cells (55°C for 10 min in 0.1% peptone water or 55°C for 15 min in sterilized skim milk) were inoculated directly onto solidified TSA. After a 2-h incubation period for cell repair, selective agar was applied to the TSA surface with a sprayer, and the plates were incubated. The recovery rate for heat-injured Salmonella Typhimurium and L. monocytogenes with the spray method was compared with the corresponding rates associated with TSA alone, selective media alone, and the conventional overlay method (selective agar poured on top of resuscitated cells grown on TSA and incubated for 2 h). No significant differences (P > 0.05) were found in pathogen recovery obtained with TSA, the overlay method, and the spray method. However, a lower recovery rate (P < 0.05) was obtained for isolation of injured cells on selective media. Overall, these results indicate that the agar spray method is an acceptable alternative to the conventional overlay method and is a simpler and more convenient approach to recovery and detection of injured cells.

Research on the Fatigue Flexural Performance of RC Beams Attacked by Salt Spray

NASA Astrophysics Data System (ADS)

Mao, Jiang-hong; Xu, Fang-yuan; Jin, Wei-liang; Zhang, Jun; Wu, Xi-xi; Chen, Cai-sheng

2018-04-01

The fatigue flexural performance of RC beams attacked by salt spray was studied. A testing method involving electro osmosis, electrical accelerated corrosion and salt spray was proposed. This corrosion process method effectively simulates real-world salt spray and fatigue loading exerted by RC components on sea bridges. Four RC beams that have different stress amplitudes were tested. It is found that deterioration by corrosion and fatigue loading reduces the fatigue life of the RC and decreases the ability of deformation. The fatigue life and deflection ability could be reduced by increasing the stress amplitude and the corrosion duration time. The test result demonstrates that this experimental method can couple corrosion deterioration and fatigue loading reasonably. This procedure may be applied to evaluate the fatigue life and concrete durability of RC components located in a natural salt spray environment.

Molecular characterization and comparison of shale oils generated by different pyrolysis methods

USGS Publications Warehouse

Birdwell, Justin E.; Jin, Jang Mi; Kim, Sunghwan

2012-01-01

Shale oils generated using different laboratory pyrolysis methods have been studied using standard oil characterization methods as well as Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) with electrospray ionization (ESI) and atmospheric photoionization (APPI) to assess differences in molecular composition. The pyrolysis oils were generated from samples of the Mahogany zone oil shale of the Eocene Green River Formation collected from outcrops in the Piceance Basin, Colorado, using three pyrolysis systems under conditions relevant to surface and in situ retorting approaches. Significant variations were observed in the shale oils, particularly the degree of conjugation of the constituent molecules and the distribution of nitrogen-containing compound classes. Comparison of FT-ICR MS results to other oil characteristics, such as specific gravity; saturate, aromatic, resin, asphaltene (SARA) distribution; and carbon number distribution determined by gas chromatography, indicated correspondence between higher average double bond equivalence (DBE) values and increasing asphaltene content. The results show that, based on the shale oil DBE distributions, highly conjugated species are enriched in samples produced under low pressure, high temperature conditions, and under high pressure, moderate temperature conditions in the presence of water. We also report, for the first time in any petroleum-like substance, the presence of N4 class compounds based on FT-ICR MS data. Using double bond equivalence and carbon number distributions, structures for the N4 class and other nitrogen-containing compounds are proposed.

Pyrolysis-gas chromatography/mass spectrometry analyses of biological particulates collected during recent space shuttle missions

NASA Technical Reports Server (NTRS)

Matney, M. L.; Limero, T. F.; James, J. T.

1994-01-01

Biological particulates collected on air filters during shuttle missions (STS-40 and STS-42) were identified using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). A method was developed for identifying the atmospheric particles and their sources through the analysis of standard materials and the selection of "marker" compounds specific to the particle type. Pyrolysis spectra of biological standards were compared with those of airborne particles collected during two space shuttle missions; marker compounds present in the shuttle particle spectra were matched with those of the standards to identify the source of particles. Particles of 0,5--1-mm diameter and weighing as little as 40 micrograms could be identified using this technique. The Py-GC/MS method identified rat food and soilless plant-growth media as two sources of particles collected from the shuttle atmosphere during flight.

Study of phase development and thermal stability in as synthesized TiO2 nanoparticles by laser pyrolysis: ethylene uptake and oxygen enrichment

NASA Astrophysics Data System (ADS)

Ilie, Alina Georgiana; Scarisoreanu, Monica; Dutu, Elena; Dumitrache, Florian; Banici, Ana-Maria; Fleaca, Claudiu Teodor; Vasile, Eugenia; Mihailescu, Ion

2018-01-01

Laser pyrolysis has proven a viable and trustworthy method of TiO2 nanoparticles fabrication, ensuring good quality and wide variety of nanoparticle morphologies and sizes. This work is aimed to phase control, experimentally studied, by parameter modulation, during one step laser pyrolysis synthesis or in combination with thermal annealing. High phase purity anatase and rutile TiO2 nanoparticles, oxygen abundant, are synthesized from TiCl4 and C2H4 gas mixtures, in the presence of air as oxygen donor, under CO2 laser radiation. The nano-titania samples are analyzed by X-ray Diffraction, EDAX, TEM and Raman spectroscopy and reveal good phase stability and distinct morphology. This study extends the method applicability onto rutile majoritarian TiO2 synthesis and generation of thermally stable anatase titania, a well-known catalyst.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sabah, Fayroz A., E-mail: fayroz-arif@yahoo.com; Department of Electrical Engineering, College of Engineering, Al-Mustansiriya University, Baghdad; Ahmed, Naser M., E-mail: naser@usm.my

The copper sulphide (CuS) thin films were grown with good adhesion by spray pyrolysis deposition (SPD) on Ti, ITO and glass substrates at 200 °C. The distance between nozzle and substrate is 30 cm. The composition was prepared by mixing copper chloride CuCl{sub 2}.2H{sub 2}O as a source of Cu{sup 2+} and sodium thiosulfate Na{sub 2}S{sub 2}O{sub 3}.5H{sub 2}O as a source of and S{sup 2−}. Two concentrations (0.2 and 0.4 M) were used for each CuCl{sub 2} and Na{sub 2}S{sub 2}O{sub 3} to be prepared and then sprayed (20 ml). The process was started by spraying the solution formore » 3 seconds and after 10 seconds the cycle was repeated until the solution was sprayed completely on the hot substrates. The structural characteristics were studied using X-ray diffraction; they showed covellite CuS hexagonal crystal structure for 0.2 M concentration, and covellite CuS hexagonal crystal structure with two small peaks of chalcocite Cu{sub 2}S hexagonal crystal structure for 0.4 M concentration. Also the surface and electrical characteristics were investigated using Field Emission Scanning Electron Microscopy (FESEM) and current source device, respectively. The surface study for the CuS thin films showed nanorods to be established for 0.2 M concentration and mix of nanorods and nanoplates for 0.4 M concentration. The electrical study showed ohmic behavior and low resistivity for these films. Hall Effect was measured for these thin films, it showed that all samples of CuS are p- type thin films and ensured that the resistivity for thin films of 0.2 M concentration was lower than that of 0.4 M concentration; and for the two concentrations CuS thin film deposited on ITO had the lowest resistivity. This leads to the result that the conductivity was high for CuS thin film deposited on ITO substrate, and the conductivity of the three thin films of 0.2 M concentration was higher than that of 0.4 M concentration.« less

Systems and methods for coating conduit interior surfaces utilizing a thermal spray gun with extension arm

DOEpatents

Moore, Karen A.; Zatorski, Raymond A.

2005-07-12

Systems and methods for applying a coating to an interior surface of a conduit. In one embodiment, a spray gun configured to apply a coating is attached to an extension arm which may be inserted into the bore of a pipe. The spray gun may be a thermal spray gun adapted to apply a powder coating. An evacuation system may be used to provide a volume area of reduced air pressure for drawing overspray out of the pipe interior during coating. The extension arm as well as the spray gun may be cooled to maintain a consistent temperature in the system, allowing for more consistent coating.

Methods for coating conduit interior surfaces utilizing a thermal spray gun with extension arm

DOEpatents

Moore, Karen A.; Zatorski, Raymond A.

2007-10-02

Systems and methods for applying a coating to an interior surface of a conduit. In one embodiment, a spray gun configured to apply a coating is attached to an extension arm which may be inserted into the bore of a pipe. The spray gun may be a thermal spray gun adapted to apply a powder coating. An evacuation system may be used to provide a volume area of reduced air pressure for drawing overspray out of the pipe interior during coating. The extension arm as well as the spray gun may be cooled to maintain a consistent temperature in the system, allowing for more consistent coating.

Development of a plasma sprayed ceramic gas path seal for high pressure turbine application

NASA Technical Reports Server (NTRS)

Shiembob, L. T.

1978-01-01

Development of the plasma sprayed graded, layered ZRO2/CoCrAlY seal system for gas turbine engine blade tip seal applications up to 1589 K (2400 F) surface temperature was continued. The effect of changing ZRO2/CoCrAlY ratios in the intermediate layers on thermal stresses was evaluated analytically with the goal of identifying the materials combinations which would minimize thermal stresses in the seal system. Three methods of inducing compressive residual stresses in the sprayed seal materials to offset tensile thermal stresses were analyzed. The most promising method, thermal prestraining, was selected based upon potential, feasibility and complexity considerations. The plasma spray equipment was modified to heat, control and monitor the substrate temperature during spraying. Specimens were fabricated and experimentally evaluated to: (1) substantiate the capability of the thermal prestrain method to develop compressive residual stresses in the sprayed structure and (2) define the effect of spraying on a heated substate on abradability, erosion and thermal shock characteristics of the seal system. Thermal stress analysis, including residual stresses and material properties variations, was performed and correlated with thermal shock test results. Seal system performance was assessed and recommendations for further development were made.

Structural, Optical, and Vibrational Properties of ZnO Microrods Deposited on Silicon Substrate

NASA Astrophysics Data System (ADS)

Lahlouh, Bashar I.; Ikhmayies, Shadia J.; Juwhari, Hassan K.

2018-03-01

Zinc oxide (ZnO) microrod films deposited by spray pyrolysis on silicon substrate at 350 ± 5°C have been studied and evaluated, and compared with thin films deposited by electron beam to confirm the identity of the studied samples. The films were characterized using different techniques. The microrod structure was studied and confirmed by scanning electron microscopy. Fourier-transform infrared (FTIR) spectroscopy and x-ray diffraction analysis confirmed successful deposition of ZnO thin films with the expected wurtzite structure. Reflectance data showed a substantial drop across the whole studied wavelength range. The photoluminescence (PL) spectra of the studied samples showed a peak at ˜ 360 nm, representing a signature of ZnO. The shift in the PL peak position is due to defects and other species present in the films, as confirmed by FTIR and energy-dispersive x-ray spectroscopy results.

Chlorine gas sensing performance of palladium doped nickel ferrite thin films

NASA Astrophysics Data System (ADS)

Rao, Pratibha; Godbole, R. V.; Bhagwat, Sunita

2016-05-01

NiFe2O4 and Pd:NiFe2O4 (Pd=1 w/o, 3 w/o and 5 w/o) thin films, p-type semiconducting oxides with an inverse spinel structure have been used as a gas sensor to detect chlorine. These films were prepared by spray pyrolysis technique and XRD was used to confirm the structure. The surface morphology was studied using SEM. Magnetization measurements were carried out at room temperature using SQUID VSM, which shows ferrimagnetic behavior of the samples. The reduction in optimum operating temperature and enhancement in response was observed on Pd-incorporation in nickel ferrite thin films. Faster response and recovery characteristic is observed Pd-incorporated nickel ferrite thin films. The long-term stability is evaluated over a period of six months. This feature may be regarded as a significant facet towards their practical application as gas sensors.

Growth and characterization of highly conducting Al-doped ZnO (AZO) thin films for optoelectronic applications

NASA Astrophysics Data System (ADS)

Sardana, Sanjay K.; Singh, Anil; Srivastava, Sanjay K.; Pandya, Dinesh K.

2018-05-01

A comparative study of undoped ZnO and Al-doped ZnO (AZO) thin films deposited on glass substrate by spray pyrolysis has been carried out at various aqueous molar concentration of zinc acetate. The thin films deposited on glass shows the wurtzite phase of ZnO, confirmed by X-ray diffraction. The optical study shows the high transmittance over 80% in the visible regime. The band gap of AZO thin films shows a blue shift as compared to undoped ZnO, which has been attributed to Burstein-Moss shift. Heat treatment of these samples in vacuum showed the improved conductivity in compared to as-deposited thin films. The electric study shows the minimum resistivity of 8 x 10-3 Ω-cm and carrier concentration of 6.5 × 1019 /cm3 correspond to AZO thin films.

PAC characterization of Gd and Y doped nanostructured zirconia solid solutions

NASA Astrophysics Data System (ADS)

Caracoche, María C.; Martínez, Jorge A.; Pasquevich, Alberto F.; Rivas, Patricia C.; Djurado, Elizabeth; Boulc'h, Florence

2007-02-01

A perturbed angular correlation (PAC) study as a function of temperature has been carried out on spray pyrolysis-derived powders and compacts of 2.5 mol% Y 2O 3-ZrO 2 and 2 mol% Gd 2O 3-ZrO 2 nanostructured tetragonal zirconias. The powders undergo the ordinary thermal transformation between the two known defective t‧- and regular t-tetragonal forms and also a partial and irreversible change to an ordered cubic configuration. The dynamical nature of the t‧-form leads to an activation energy of about 0.15 eV for the oxygen vacancies movement. The as-obtained compacts do not exhibit any known cubic nanostructure but some additional contributions. In both of them a hyperfine component assigned to the orthorhombic phase is determined. In the smaller cation Y doped ceramic a small amount of monoclinic phase reflects an incomplete stabilization.

Annealing induced reorientation of crystallites in Sn doped ZnO films

NASA Astrophysics Data System (ADS)

Ravichandran, K.; Vasanthi, M.; Thirumurugan, K.; Sakthivel, B.; Karthika, K.

2014-11-01

Tin doped ZnO thin films were prepared by employing a simplified spray pyrolysis technique using a perfume atomizer and subsequently annealed under different temperatures from 350 °C to 500 °C in steps of 50 °C. The structural, optical, electrical, photoluminescence and surface morphological properties of the as-deposited films were studied and compared with that of the annealed films. The X-ray diffraction studies showed that as-deposited film exhibits preferential orientation along the (0 0 2) plane and it changes in favour of (1 0 0) plane after annealing. The increase in crystallite size due to annealing is explained on the basis of Ostwald ripening effect. It is found that the optical transmittance and band gap increases with increase in annealing temperature. A slight decrease in resistivity caused by annealing is discussed in correlation with annealing induced defect modifications and surface morphology.

Effect of autohydrolysis pretreatment on biomass structure and the resulting bio-oil from a pyrolysis process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hao, Naijia; Bezerra, Tais Lacerda; Wu, Qiong

Pyrolysis is a promising method for converting biomass to biofuels. However, some of pyrolysis oil's physiochemical properties still limit its commercial applications. Here, the autohydrolysis pretreatment at 175 ± 3 °C for 40 min was conducted to improve the resulting pine pyrolysis oil’s properties as a fuel. During autohydrolysis, deacetylation and decomposition of hemicellulose was observed by ion-exchange chromatography and Fourier transform infrared spectroscopy (FT-IR). Additionally, the cleavage of lignin ether bonds was clearly determined by 13C cross-polarization/magic angle spinning (CP/MAS) nuclear magnetic resonance (NMR). Phosphitylation followed by 31P NMR analysis of the heavy oils gave detailed structural information ofmore » the hydroxyl groups; the results revealed that autohydrolysis pretreatment led to a reduction of carboxyl acids in the heavy oils generated at all three pyrolysis temperatures (400, 500, and 600 °C). The 31P NMR analysis also revealed that autohydrolysis pretreatment led to a reduction of condensed phenolic hydroxyl groups in the heavy oils produced at 600 °C. 1H- 13C heteronuclear single-quantum correlation (HSQC) NMR analysis showed that at a pyrolysis temperature of 600 °C, the pretreated pine produced lower methoxy group constituents. In both 31P and HSQC NMR results indicated that autohydrolysis pretreatment increased levoglucosan yields in the bio-oils.« less