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1

Anode property of boron-doped graphite materials for rechargeable lithium-ion batteries  

Microsoft Academic Search

Anode properties of boron-doped graphites were investigated by means of electrochemical measurements. A discharge capacity of about 315 mAh\\/g was obtained for 3.8 mass% boron-doped pitch coke-derived graphite in galvanostatic measurements. Increased discharge capacity for boron-doped graphite compared with boron-free one was considered to be mainly due to the enhanced graphitization by boron. Also, in this measurements, a shoulder was

Udai Tanaka; Toshiaki Sogabe; Haruo Sakagoshi; Masayuki Ito; Tetsuro Tojo

2001-01-01

2

Structure and electrochemical applications of boron-doped graphitized carbon nanofibers  

Microsoft Academic Search

Boron-doped graphitized carbon nanofibers (CNFs) were prepared by optimizing CNFs preparation, surface treatment, graphitization and boron-added graphitization. The interlayer spacing (d002) of the boron-doped graphitized CNFs reached 3.356 ?, similar to that of single-crystal graphite. Special platelet CNFs (PCNFs), for which d002 is less than 3.400 ?, were selected for further heat treatment. The first heat treatment of PCNFs at

Jae-Seong Yeo; Sang-Min Jang; Jin Miyawaki; Bai An; Isao Mochida; Choong Kyun Rhee; Seong-Ho Yoon

2012-01-01

3

Electrochemical reactivity at graphitic micro-domains on polycrystalline boron doped diamond thin-films electrodes  

Microsoft Academic Search

This paper deals with the electrochemical reactivity of boron doped diamond (BDD) electrodes. A comparative study has been carried out to show the influence of the presence of graphitic micro-domains upon the surface of these films. Those graphitic domains are sometimes present on as-grown boron doped diamond electrodes. The effect of doping a pure Csp3 diamond electrode is established by

E. Mahé; D. Devilliers; Ch. Comninellis

2005-01-01

4

Structure and electrochemical applications of boron-doped graphitized carbon nanofibers  

NASA Astrophysics Data System (ADS)

Boron-doped graphitized carbon nanofibers (CNFs) were prepared by optimizing CNFs preparation, surface treatment, graphitization and boron-added graphitization. The interlayer spacing (d002) of the boron-doped graphitized CNFs reached 3.356 Å, similar to that of single-crystal graphite. Special platelet CNFs (PCNFs), for which d002 is less than 3.400 Å, were selected for further heat treatment. The first heat treatment of PCNFs at 2800?°C yielded a d002 between 3.357 and 3.365 Å. Successive nitric acid treatment and a second heat treatment with boric acid reduced d002 to 3.356 Å. The resulting boron-doped PCNFs exhibited a high discharge capacity of 338 mAh g-1 between 0 and 0.5 V versus Li/Li+ and 368 mAh g-1 between 0 and 1.5 V versus Li/Li+. The first-cycle Coulombic efficiency was also enhanced to 71-80%. Such capacity is comparable to that of natural graphite under the same charge/discharge conditions. The boron-doped PCNFs also exhibited improved rate performance with twice the capacity of boron-doped natural graphite at a discharge rate of 5 C.

Yeo, Jae-Seong; Jang, Sang-Min; Miyawaki, Jin; An, Bai; Mochida, Isao; Rhee, Choong Kyun; Yoon, Seong-Ho

2012-08-01

5

Structure and electrochemical applications of boron-doped graphitized carbon nanofibers.  

PubMed

Boron-doped graphitized carbon nanofibers (CNFs) were prepared by optimizing CNFs preparation, surface treatment, graphitization and boron-added graphitization. The interlayer spacing (d???) of the boron-doped graphitized CNFs reached 3.356 ?, similar to that of single-crystal graphite. Special platelet CNFs (PCNFs), for which d??? is less than 3.400 ?, were selected for further heat treatment. The first heat treatment of PCNFs at 2800?°C yielded a d??? between 3.357 and 3.365 ?. Successive nitric acid treatment and a second heat treatment with boric acid reduced d??? to 3.356 ?. The resulting boron-doped PCNFs exhibited a high discharge capacity of 338 mAh g?¹ between 0 and 0.5 V versus Li/Li? and 368 mAh g?¹ between 0 and 1.5 V versus Li/Li?. The first-cycle Coulombic efficiency was also enhanced to 71-80%. Such capacity is comparable to that of natural graphite under the same charge/discharge conditions. The boron-doped PCNFs also exhibited improved rate performance with twice the capacity of boron-doped natural graphite at a discharge rate of 5 C. PMID:22797214

Yeo, Jae-Seong; Jang, Sang-Min; Miyawaki, Jin; An, Bai; Mochida, Isao; Rhee, Choong Kyun; Yoon, Seong-Ho

2012-08-10

6

Enhanced metastability of high-density Li intercalation in boron-doped graphite  

NASA Astrophysics Data System (ADS)

High-pressure reaction of Li metal and graphite yields LiC 2, three times as dense in Li as the usual LiC 6. LiC 6 decomposes rapidly but incompletely into LiC 6 + Li upon releasing pressure. A dramatic enhancement is observed in the metastability of the high Li density when the graphite contains 0.5 at.% substitutional boron. Average compositions from X-ray (OOL) intensities, determined several months after releasing the pressure, are LiC 2.2 and LiC 3.8 with and without boron respectively. The Li "layer" is split along c by 0.5 Å suggesting a puckering which reduces the repulsive interactions.

Nalimova, Vera A.; Bindra, Chetna; Fischer, John E.

1996-02-01

7

Enhanced Metastability of High-Density Li Intercalation in Boron-Doped Graphite  

NASA Astrophysics Data System (ADS)

High-pressure reaction of Li metal and graphite yields LiC_2, three times as dense in Li as the usual LiC_6. LiC2 decomposes rapidly but incompletely into LiC6 + Li upon releasing pressure (V. A. Nalimova, D. Guerard, M. Lelaurain and O. V. Fateev, Carbon 33, 177 (1995)). A dramatic enhancement is observed in the metastability of the high Li density when the graphite contains 0.5 at.% substitutional boron. Average compositions from x-ray (OOL) intensities, determined several months after releasing the pressure, are LiC_2.2 and LiC_3.8 with and without boron respectively. The Li ``layer'' is split along c by 0.5 Å suggesting a puckering which reduces the repulsive interactions. Supported by DOE, DE-FC02-86ER45254 and by NATO Linkage Grant 921350. We are very grateful to Ingvey Fei and Michael Walter for help with the high pressure synthesis at the the Geophysical Laboratory, Carnegie Institution, and to Arthur Moore, Advanced Ceramics Corp., for the gifts of HOPG and B-HOPG.

Bindra, Chetna; Fischer, John E.; Nalimova, Vera A.

1996-03-01

8

Boron-Doped Nanocrystalline Diamond.  

National Technical Information Service (NTIS)

A conductive boron doped nanocrystalline diamond is described. The boron doped diamond has a conductivity which uses the boron in the crystals as a charge carrier. The diamond is particularly useful for electrochemical electrodes in oxidation-reduction re...

G. M. Swain M. Witek P. Sonthalia Y. Show

2004-01-01

9

Fullerene and onion formation under electron irradiation of boron-doped graphite  

Microsoft Academic Search

The formation of single- and multi-shelled fullerene-type cages and onion-like nanoscale structures has been achieved in situ during electron irradiation of graphitic BxC1?x (x?0.2) in a high resolution electron microscope. Once formed, the curled and closed structures were found to be quite stable to irradiation-induced damage. The B\\/C ratio was typically in the range of 0.02–0.10, as confirmed by electron

D Golberg; Y Bando; K Kurashima; T Sasaki

1999-01-01

10

Microstructure and electrochemical properties of boron-doped mesocarbon microbeads  

SciTech Connect

The microstructure and electrochemical properties of pristine and boron-doped mesocarbon microbeads (MCMBs) were comparatively studied by X-ray diffraction, field-emission scanning electron microscopy, Raman spectroscopy, and electrochemical measurements. The authors examined the correlation between the boron-doping effect and the electrochemical properties of boron-doped MCMBs prepared at different heat-treatment temperatures. It was found that boron doping in MCMBs starts above 1,800 C, and then the substitution reaction proceeds with increasing heat-treatment temperature. The effect of boron doping is to accelerate graphitization of MCMBs for heat-treatment temperatures in the range from 1,800 to 2,500 C. Electrochemical lithium intercalation takes place at a higher potential in boron-doped MCMBs than in undoped MCMBs, presumably because the substitutional boron acts as an electron acceptor in the MCMBs.

Kim, C.; Fujino, T.; Miyashita, K.; Hayashi, T.; Endo, M.; Dresselhaus, M.S.

2000-04-01

11

Characterization of boron doped nanocrystalline diamonds  

NASA Astrophysics Data System (ADS)

Nanostructured diamond doped with boron was prepared using a hot-filament assisted chemical vapour deposition system fed with an ethyl alcohol, hydrogen and argon mixture. The reduction of the diamond grains to the nanoscale was produced by secondary nucleation and defects induced by argon and boron atoms via surface reactions during chemical vapour deposition. Raman measurements show that the samples are nanodiamonds embedded in a matrix of graphite and disordered carbon grains, while morphological investigations using field electron scanning microscopy show that the size of the grains ranges from 20 to 100 nm. The lowest threshold fields achieved were in the 1.6 to 2.4 V/?m range.

Peterlevitz, A. C.; Manne, G. M.; Sampaio, M. A.; Quispe, J. C. R.; Pasquetto, M. P.; Iannini, R. F.; Ceragioli, H. J.; Baranauskas, V.

2008-03-01

12

Boron doping a semiconductor particle  

SciTech Connect

A method (10,30) of boron doping a semiconductor particle using boric acid to obtain a p-type doped particle. Either silicon spheres or silicon powder is mixed with a diluted solution of boric acid having a predetermined concentration. The spheres are dried (16), with the boron film then being driven (18) into the sphere. A melt procedure mixes the driven boron uniformly throughout the sphere. In the case of silicon powder, the powder is metered out (38) into piles and melted/fused (40) with an optical furnace. Both processes obtain a p-type doped silicon sphere with desired resistivity. Boric acid is not a restricted chemical, is inexpensive, and does not pose any special shipping, handling, or disposal requirements.

Stevens, Gary Don (18912 Ravenglen Ct., Dallas, TX 75287); Reynolds, Jeffrey Scott (703 Horizon, Murphy, TX 75094); Brown, Louanne Kay (2530 Poplar Tr., Garland, TX 75042)

1998-06-09

13

Boron doping a semiconductor particle  

SciTech Connect

A method of boron doping a semiconductor particle using boric acid to obtain a p-type doped particle. Either silicon spheres or silicon powder is mixed with a diluted solution of boric acid having a predetermined concentration. The spheres are dried, with the boron film then being driven into the sphere. A melt procedure mixes the driven boron uniformly throughout the sphere. In the case of silicon powder, the powder is metered out into piles and melted/fused with an optical furnace. Both processes obtain a p-type doped silicon sphere with desired resistivity. Boric acid is not a restricted chemical, is inexpensive, and does not pose any special shipping, handling, or disposal requirements. 2 figs.

Stevens, G.D.; Reynolds, J.S.; Brown, L.K.

1998-06-09

14

Boron doped nanostructured diamond films  

NASA Astrophysics Data System (ADS)

A chemical vapor deposition hydrogen/methane/nitrogen feed-gas mixture with unconventionally high methane (15% CH4 by volume) normally used to grow ultra-hard and smooth nanostructured diamond films on Ti-6Al-4V alloy substrates was modified to include diborane B2H6 for boron-doping of diamond films. The flow rates for B2H 6 and N2 were varied to investigate their effect on plasma chemistry, film structure, boron incorporation, and mechanical properties. It was found that boron atoms can easily be incorporated into diamond films and change the lattice constant and film structure. Nitrogen, on the other hand, competes with boron in the plasma and acts to prevent boron incorporation into the diamond structure. In addition, with the appropriate choice of deposition conditions, the film structure can be tailored to range from highly crystalline, well faceted diamond to nanocrystalline diamond. Glancing angle X-ray diffraction and Micro-Raman were used as the main tools to investigate the relation between processing and structure. An optimal N2/CH4 ratio of 0.4 was found to result in a film with a minimum in grain size and surface roughness, along with high boron incorporation (˜4 x 1020 cm-3). Mechanical properties and thermal stability of boron doped nanostructured diamond films were examined by means of nanoindentation, open air thermal annealing, and nanotribometry. It was found that the films have high hardness close to that of undoped nanostructured diamond films. Thermal stability of these films was evaluated by heating in an oxygen environment above 700°C. Improved thermal stability of boron doped nanostructured diamond films was observed. Tribological tests show that although both undoped and boron doped nanostructured diamond films show extremely low coefficient of friction and wear rate as compared with uncoated titanium alloys (Ti-6Al-4V) and cobalt chrome alloy (Co-Cr-Mo), a critical failure max stress of 2.2 GPa was observed for boron doped nanostructured diamond films. A FORTRAN Chemical Kinetics Package for the Analysis of Gas Phase Chemical Kinetics, gas-phase thermodynamic equilibrium calculations involving H 2/CH4/N2/B2H6 mixtures was employed to investigate the chemical interactions leading to boron incorporation and crystalline structure variations. The strong influence of the BH 3 in causing the boron incorporation and the role of CN radical in causing the nanocrystallinity are confirmed by the correlation of their modeled compositions in the gas phase with boron content and degree of nanocrystallinity as determined experimentally. A good degree of agreement was obtained between the theoretically predicted gas phase concentration of species and the experimental concentration trends as measured by the optical emission spectroscopy of the microwave plasma. Overall, high film hardness and toughness, combined with good thermal stability and low surface roughness, indicate that nanostructured boron doped diamond films can be used as wear resistant coatings that are able to withstand high temperature oxidizing environments.

Liang, Qi

15

Optical properties of boron-doped diamond  

NASA Astrophysics Data System (ADS)

We report optical reflectivity study on pure and boron-doped diamond films grown by a hot-filament chemical vapor deposition method. The study reveals the formation of an impurity band close to the top of the valence band upon boron doping. A schematic picture for the evolution of the electronic structure with boron doping was drawn based on the experimental observation. The study also reveals that the boron doping induces local lattice distortion, which brings an infrared-forbidden phonon mode at 1330cm-1 activated in the doped sample. The antiresonance characteristic of the mode in conductivity spectrum evidences the very strong coupling between electrons and this phonon mode.

Wu, Dan; Ma, Y. C.; Wang, Z. L.; Luo, Q.; Gu, C. Z.; Wang, N. L.; Li, C. Y.; Lu, X. Y.; Jin, Z. S.

2006-01-01

16

Graphite and boron carbide composites made by hot-pressing  

Microsoft Academic Search

Composites consisting of graphite and boron carbide were made by hot-pressing mixed powders of coke carbon and boron carbide. The change of relative density, mechanical strength and electrical resistivity of the composites and the X-ray parameters of coke carbon were investigated with increase of boron carbide content and hot-pressing temperature. From these experiments, it was found that boron carbide powder

Kenji Miyazaki; Tsuyoshi Hagio; Kazuo Kobayashi

1981-01-01

17

Graphite and boron carbide composites made by hot-pressing  

Microsoft Academic Search

Composites consisting of graphite and boron carbide were made by hot-pressing mixed powders of coke carbon and boron carbide.\\u000a The change of relative density, mechanical strength and electrical resistivity of the composites and the X-ray parameters\\u000a of coke carbon were investigated with increase of boron carbide content and hot-pressing temperature. From these experiments,\\u000a it was found that boron carbide powder

Kenji Miyazaki; Tsuyoshi Hagio; Kazuo Kobayashi

1981-01-01

18

Vortex fluidic exfoliation of graphite and boron nitride.  

PubMed

Graphite is exfoliated into graphene by shearing vortex fluidic films of N-methyl-pyrrolidone (NMP), as a controlled process for preparing oxide free graphene, and for exfoliating the corresponding boron nitride sheets. PMID:22314550

Chen, Xianjue; Dobson, John F; Raston, Colin L

2012-04-18

19

TOPICAL REVIEW: 11B nuclear magnetic resonance in boron-doped diamond  

NASA Astrophysics Data System (ADS)

This review summarizes recent results obtained by 11B solid-state nuclear magnetic resonance (NMR) on boron-doped diamond, grown by the high-pressure high-temperature (HPHT) or chemical vapor deposition techniques. Simple single-pulse experiments as well as advanced two-dimensional NMR experiments were applied to the boron sites in diamond. It is shown that magic-angle spinning at magnetic fields above 10 T is suitable for observation of high-resolution 11B spectra of boron-doped diamond. For boron-doped HPHT diamonds, the existence of the excess boron that does not contribute to electrical conductivity was confirmed and its 11B NMR signal was characterized. The point-defect structures (B+H complexes and -B-B-/-B-C-B- clusters), postulated previously for the excess boron, were discarded and graphite-like structures were assigned instead.

Murakami, Miwa; Shimizu, Tadashi; Tansho, Masataka; Takano, Yoshihiko

2008-10-01

20

Catalyst-free synthesis of crumpled boron and nitrogen co-doped graphite layers with tunable bond structure for oxygen reduction reaction.  

PubMed

Two-dimensional materials based on ternary system of B, C and N are useful ranging from electric devices to catalysis. The bonding arrangement within these BCN nanosheets largely determines their electronic structure and thus chemical and (or) physical properties, yet it remains a challenge to manipulate their bond structures in a convenient and controlled manner. Recently, we developed a synthetic protocol for the synthesis of crumpled BCN nanosheets with tunable B and N bond structure using urea, boric acid and polyethylene glycol (PEG) as precursors. By carefully selecting the synthesis condition, we can tune the structure of BCN sheets from s-BCN with B and N bond together to h-BCN with B and N homogenously dispersed in BCN sheets. Detailed experiments suggest that the final bond structure of B and N in graphene depends on the preferentially doped N structure in BCN nanosheets. When N substituted the in-plane carbon atom with all its electrons configured into the ? electron system of graphene, it facilitates the formation of h-BCN with B and N in separated state. On the contrary, when nitrogen substituted the edge-plane carbon with the nitrogen dopant surrounded with the lone electron pairs, it benefits for the formation of B-N structure. Specially, the compound riched with h-BCN shows excellent ORR performance in alkaline solution due to the synergistic effect between B and N, while s-BCN dominant BCN shows graphite-like activity for ORR, suggesting the intrinsic properties differences of BCN nanosheets with different dopants bond arrangement. PMID:24601550

Jin, Jutao; Pan, Fuping; Jiang, Luhua; Fu, Xiaogang; Liang, Aiming; Wei, Zhiyang; Zhang, Junyan; Sun, Gongquan

2014-04-22

21

Structure and functionality of bromine doped graphite  

NASA Astrophysics Data System (ADS)

First-principles calculations are used to study the enhanced in-plane conductivity observed experimentally in Br-doped graphite, and to study the effect of external stress on the structure and functionality of such systems. The model used in the numerical calculations is that of stage two doped graphite. The band structure near the Fermi surface of the doped systems with different bromine concentrations is compared to that of pure graphite, and the charge transfer between carbon and bromine atoms is analyzed to understand the conductivity change along different high symmetry directions. Our calculations show that, for large interlayer separation between doped graphite layers, bromine is stable in the molecular form (Br2). However, with increased compression (decreased layer-layer separation) Br2 molecules tend to dissociate. While in both forms, bromine is an electron acceptor. The charge exchange between the graphite layers and Br atoms is higher than that with Br2 molecules. Electron transfer to the Br atoms increases the number of hole carriers in the graphite sheets, resulting in an increase of conductivity.

Hamdan, Rashid; Kemper, A. F.; Cao, Chao; Cheng, H. P.

2013-04-01

22

Structure and functionality of bromine doped graphite.  

PubMed

First-principles calculations are used to study the enhanced in-plane conductivity observed experimentally in Br-doped graphite, and to study the effect of external stress on the structure and functionality of such systems. The model used in the numerical calculations is that of stage two doped graphite. The band structure near the Fermi surface of the doped systems with different bromine concentrations is compared to that of pure graphite, and the charge transfer between carbon and bromine atoms is analyzed to understand the conductivity change along different high symmetry directions. Our calculations show that, for large interlayer separation between doped graphite layers, bromine is stable in the molecular form (Br2). However, with increased compression (decreased layer-layer separation) Br2 molecules tend to dissociate. While in both forms, bromine is an electron acceptor. The charge exchange between the graphite layers and Br atoms is higher than that with Br2 molecules. Electron transfer to the Br atoms increases the number of hole carriers in the graphite sheets, resulting in an increase of conductivity. PMID:23635160

Hamdan, Rashid; Kemper, A F; Cao, Chao; Cheng, H P

2013-04-28

23

Local atomic and electronic structure of boron chemical doping in monolayer graphene.  

PubMed

We use scanning tunneling microscopy and X-ray spectroscopy to characterize the atomic and electronic structure of boron-doped and nitrogen-doped graphene created by chemical vapor deposition on copper substrates. Microscopic measurements show that boron, like nitrogen, incorporates into the carbon lattice primarily in the graphitic form and contributes ~0.5 carriers into the graphene sheet per dopant. Density functional theory calculations indicate that boron dopants interact strongly with the underlying copper substrate while nitrogen dopants do not. The local bonding differences between graphitic boron and nitrogen dopants lead to large scale differences in dopant distribution. The distribution of dopants is observed to be completely random in the case of boron, while nitrogen displays strong sublattice clustering. Structurally, nitrogen-doped graphene is relatively defect-free while boron-doped graphene films show a large number of Stone-Wales defects. These defects create local electronic resonances and cause electronic scattering, but do not electronically dope the graphene film. PMID:24032458

Zhao, Liuyan; Levendorf, Mark; Goncher, Scott; Schiros, Theanne; Pálová, Lucia; Zabet-Khosousi, Amir; Rim, Kwang Taeg; Gutiérrez, Christopher; Nordlund, Dennis; Jaye, Cherno; Hybertsen, Mark; Reichman, David; Flynn, George W; Park, Jiwoong; Pasupathy, Abhay N

2013-10-01

24

Ground-state properties of boron-doped diamond  

SciTech Connect

Boron-doped diamond undergoes an insulator-metal or even a superconducting transition at some critical value of the dopant concentration. We study the equilibrium lattice parameter and bulk modulus of boron-doped diamond experimentally and in the framework of the density functional method for different levels of boron doping. We theoretically consider the possibility for the boron atoms to occupy both substitutional and interstitial positions and investigate their influence on the electronic structure of the material. The data suggest that boron softens the lattice, but softening due to substitutions of carbon with boron is much weaker than due to incorporation of boron into interstitial positions. Theoretical results obtained for substitution of carbon are in very good agreement with our experiment. We present a concentration dependence of the lattice parameter in boron-doped diamond, which can be used for to identify the levels of boron doping in future experiments.

Zarechnaya, E. Yu., E-mail: ezarechnaya@yahoo.com; Isaev, E. I. [Moscow State Institute of Steel and Alloys (Technological University) (Russian Federation)], E-mail: eyvaz_isaev@yahoo.com; Simak, S. I. [Linkoeping University, Department of Physics, Chemistry, and Biology (IFM) (Sweden); Vekilov, Yu. Kh. [Moscow State Institute of Steel and Alloys (Technological University) (Russian Federation); Dubrovinsky, L. S. [University of Bayreuth, Bayerisches Geoinstitut (Germany); Dubrovinskaia, N. A. [University of Heidelberg, Mineralogisches Institut (Germany); Abrikosov, I. A. [Linkoeping University, Department of Physics, Chemistry, and Biology (IFM) (Sweden)

2008-04-15

25

Synthesis and characterization of boron-doped carbons  

Microsoft Academic Search

Two methods have been employed to prepare boron-doped carbon materials. One method utilized ion implantation to dope the surface region of vitreous carbon with up to 12 atomic % boron. The other method used CVD to prepare ~ 1–2 micron thick carbon coatings with various boron contents (0 to 15 atomic %). The quantitative compositional analysis of these materials was

William Cermignani; Thomas E. Paulson; Carina Onneby; Carlo G. Pantano

1995-01-01

26

Boron and nitrogen-doped carbon nanotubes and graphene  

Microsoft Academic Search

Multi-walled, single-walled and double-walled carbon nanotubes as well as graphene can be doped with boron and nitrogen. B2H6 has been generally used as the boron source while NH3 or pyridine is employed as the nitrogen source. Doping carbon nanotubes and graphene with boron and nitrogen brings about significant changes in the electronic structure and properties. Such doping not only results

L. S. Panchakarla; A. Govindaraj; C. N. R. Rao

2010-01-01

27

Superconductivity in Li-doped ?-rhombohedral boron  

NASA Astrophysics Data System (ADS)

Metal transition and superconductivity were observed in Li-doped ?-rhombohedral boron (?-B12). The authors have established a purification method and obtained a large amount of high-purity ?-B12 powder. Li doping into purified ?-B12 was attempted by vapor diffusion processing (VDP) in a Mo or Ta tube. Li-doped ?-B12 contained metallic glittering particles. Meissner effects were observed in such a compound with the nominal composition LixB12 (x = 1.0, 1.4, 1.5, 1.7, or 2.5) (Tc = 3.2-7 K). As for Li2.5B12, the temperature dependence of its electrical conductivity indicates a metallic character and its electrical resistivity drop is detected near the Meissner temperature. The existence of Li and Fermi edges in Li-doped ?-B12 crystals was verified by transmission electron microscopy-electron energy loss spectroscopy (TEM-EELS). Lattice expansion, which is a well-known indicator of metal doping into a crystal, was also observed. Thus, Li doping into ?-B12 was successfully achieved. Our work also suggests that it is possible to dope a larger amount of Li into ?-B12 and to increase its Tc.

Nagatochi, T.; Hyodo, H.; Sumiyoshi, A.; Soga, K.; Sato, Y.; Terauchi, M.; Esaka, F.; Kimura, K.

2011-05-01

28

Mineralization of paracetamol in aqueous medium by anodic oxidation with a boron-doped diamond electrode  

Microsoft Academic Search

The degradation of 100ml of solutions with paracetamol (N-(4-hydroxyphenyl)acetamide) up to 1gl?1 in the pH range 2.0–12.0 has been studied by anodic oxidation in a cell with a boron-doped diamond (BDD) anode and a graphite cathode, both of 3-cm2 area, by applying a current of 100, 300 and 450mA between 25 and 45°C. Complete mineralization is always achieved due to

Enric Brillas; Ignasi Sirés; Conchita Arias; Pere Lluís Cabot; Francesc Centellas; Rosa María Rodríguez; José Antonio Garrido

2005-01-01

29

Chemical surface characterization of electrochemically and thermally oxidized boron-doped diamond film electrodes  

Microsoft Academic Search

In situ Cyclic Voltammetric analysis and ex situ X-ray Photoelectron Spectroscopy investigations have been carried out on highly boron-doped diamond film electrodes subjected to different oxidative treatments. Both the electrochemical and thermal oxidation modify, at different extent, the qualitative and quantitative chemical surface composition of the as prepared samples by partially converting the non diamond carbon species, for instance graphitic-like

Sergio Ferro; Maurizio Dal Colle; Achille De Battisti

2005-01-01

30

Superconductivity in Boron-Doped Diamond  

Microsoft Academic Search

Superconductivity of boron-doped diamond, reported recently at T_c=4 K, is\\u000ainvestigated exploiting its electronic and vibrational analogies to MgB2. The\\u000adeformation potential of the hole states arising from the C-C bond stretch mode\\u000ais 60% larger than the corresponding quantity in MgB2 that drives its high Tc,\\u000aleading to very large electron-phonon matrix elements. The calculated coupling\\u000astrength \\\\lambda ~

K.-W. Lee; W. E. Pickett

2004-01-01

31

Boron-doped graphene as a promising anode for Na-ion batteries.  

PubMed

The Na-ion battery has recently gained a lot of interest as a low-cost alternative to the current Li-ion battery technology. Its feasibility strongly depends on the development of suitable electrode materials. In the present work we propose a novel anode candidate, boron-doped graphene, for the Na-ion battery. Our first-principles calculations demonstrate that the sodiation of boron-doped graphene well preserves its structural integrity. The 2D-BC3 anode has the average sodiation voltage of 0.44 V in an appropriate range to avoid the safety concerns caused by the formation of dendritic deposits. The capacity of the 2D-BC3 anode reaches ?2.04 times that of the graphite anode in a Li-ion battery and ?2.52 times that of hard carbon in a Na-ion battery. The high electronic mobility and Na mobility on boron-doped graphene indicates that it has a high potential to reach good rate performance. These suggest the promising potential of boron-doped graphene to serve as an anode for a rechargeable Na-ion battery. PMID:24760182

Ling, Chen; Mizuno, Fuminori

2014-05-14

32

Boron-doped graphene and boron-doped diamond electrodes: detection of biomarkers and resistance to fouling.  

PubMed

Doped carbon materials are of high interest as doping can change their properties. Here we wish to contrast the electrochemical behaviour of two carbon allotropes - sp(3) hybridized carbon as diamond and sp(2) hybridized carbon as graphene - doped by boron. We show that even though both materials exhibit similar heterogeneous electron transfer towards ferro/ferricyanide, there are dramatic differences towards the oxidation of biomolecules, such as ascorbic acid, uric acid, dopamine and ?-nicotinamide adenine dinucleotide (NADH). The boron-doped graphene exhibits much lower oxidation potentials than boron-doped diamond. The stability of the surfaces towards NADH oxidation product fouling has been studied and in the long term, there is no significant difference among the studied materials. The proton/electron coupled reduction of dopamine and nitroaromatic explosive (TNT) takes place on boron-doped graphene, while it is not observable at boron-doped diamond. These findings show that boron-doped sp(2) graphene and sp(3) diamond behave, in many aspects, dramatically differently and this shall have a profound influence upon their applicability as electrochemical materials. PMID:23817573

Tan, Shu Min; Poh, Hwee Ling; Sofer, Zden?k; Pumera, Martin

2013-09-01

33

Boron diffusion in extrinsically doped crystalline silicon  

NASA Astrophysics Data System (ADS)

Boron diffusion is investigated in details by monitoring B-sharp concentration profiles embedded in isoconcentration doping backgrounds. Atomistic diffusion parameters (kick-out rate g , mean-free path of the mobile species ? , and the diffusivity D ) are experimentally evaluated as a function of temperature and doping level both of p or n type. This allows for a quantitative determination of the physical phenomena involved in the B diffusion process. We found that negatively charged substitutional B diffuses by interaction with neutral or doubly positively charged self-interstitials. The BI complex formed after interaction diffuses mainly in a neutral state and, to a less extent, through singly negatively charged state. The former contributes for about one tenth to the full diffusion in intrinsic condition at 700°C whereas it plays a significant role in high n -codoping regime. Moreover, n codoping with As or P induces a Coulomb pairing between the different charge states of the dopants that reduces diffusion. Pairing effect is disentangled by the effect of BI- diffusion and pairing energies are determined for both As and P presence. The resulting quantitative model of diffusion is presented and compared with existing literature.

de Salvador, D.; Napolitani, E.; Bisognin, G.; Pesce, M.; Carnera, A.; Bruno, E.; Impellizzeri, G.; Mirabella, S.

2010-01-01

34

Magnetic properties of vacancies in a graphitic boron nitride sheet by first-principles pseudopotential calculations  

Microsoft Academic Search

We use ab initio methods to calculate the magnetic properties of vacancies in a graphitic boron nitride sheet ( g -BN). By applying a full spin-polarized description to the system, we demonstrate that the nitrogen vacancy (VN) or the boron vacancy (VB) can induce spontaneous magnetization. The magnetic nature of these intrinsic vacancies suggests that it is important to understand

M. S. Si; D. S. Xue

2007-01-01

35

Effect of Boron Addition on the Differential Capacitance of Stress-Annealed Pyrolytic Graphite.  

National Technical Information Service (NTIS)

The non-faradaic differential electrode capacity of the basal plane of boronated stress-annealed pyrolytic graphite with 0.3 weight % boron was studied in aqueous solution using an a.c. impedance bridge and compared to results previously obtained on the n...

J. P. Randin E. Yeager

1974-01-01

36

Boron-doped diamond electrodes: Fabrication, characterization, and electrochemical applications  

NASA Astrophysics Data System (ADS)

Boron-doped, polycrystalline and single-crystal diamond electrodes were fabricated by hot-filament chemical vapor deposition and characterized for electrochemical applications. Near-single-crystal diamond films were grown homoepitaxially on natural <100> diamond windows and <111> diamond macles. Diamond electrodes were also fluorinated using CF4. For 24 hour growth runs, 10 mum thick, well-faceted, polycrystalline films were obtained; homoepitaxial single-crystal films exceeded 4 mum in thickness and gave the macles or windows a deep blue color. Secondary ion mass spectroscopy indicated a uniform doping level of approximately 10 21 boron atoms/cm3, ca., 6000 ppm. Nuclear reaction analysis confirmed boron concentrations between 5000 and 8200 ppm. Electrode resistivities ranged from 0.05 to 0.001 Ohm-cm. Characteristic voltammetry features of high-quality polycrystalline diamond electrodes in 0.5M H2SO4 were a wide potential range for water stability (-1.25 to +2.3 V vs. standard hydrogen electrode) and low baseline current. On low-quality electrodes, a narrower potential range and higher baseline current approached the behavior of highly-oriented pyrolytic graphite or glassy carbon electrodes. A redox couple at E½ = +1.83 V corresponded to a combination of a reversible oxidation at the grain boundaries, e.g., by a change in oxygen functionality, and an irreversible oxidation, i.e., etching, process. Single-crystal diamond electrodes displayed the wide potential range of water stability and low baseline current, but the redox couple at +1.83 V was absent, verifying that it corresponds to grain boundary reactivity. Fluorination of polycrystalline electrodes also eliminated the redox couple, suggesting that the fluorine passivates the grain boundary reactivity. Polarization of as-grown diamond electrodes caused an irreversible addition of oxygen to the surface. The nature of the oxygen termination was investigated by attenuated total reflection FTIR through a 50 mum diamond-coated silicon wafer, while the diamond-coated surface was polarized in H2SO 4. The spectra suggested that hydroxyl groups were among the oxygen functionalities added to the surface during anodic polarization. The wide potential window of water stability permits electrochemical couples with large positive or negative standard potentials to be investigated without interference from water electrolysis. For example, oxidation of commonly used copper plating additives, polyalkylene glycol and disodium (bis(3-sulfopropyl)) disulfide, were easily measured in solutions on polycrystalline diamond.

Martin, Heidi Brumfield

37

Boron-doped carbon prepared from PFO as a lithium-ion battery anode  

NASA Astrophysics Data System (ADS)

A petroleum-based Li-ion battery anode was prepared by thermal condensation of pyrolysis fuel oil (PFO) and a subsequent carbonization process. H3BO3 was used as a catalyst for efficient thermal condensation, carbonization and battery performance. The influence of the carbonization temperature on the carbon structure and battery performance was also investigated. Notably, H3BO3 promoted thermal condensation and formation of a graphitic carbon structure and acted as a boron doping agent. Boron-doping attenuated the highly active sites in carbon and effectively controlled formation of the SEI layer, which resulted in an increase in the initial efficiency of the anode. For the sample carbonized at 900 °C, a reversible capacity of 301 mAh/g and an initial efficiency of 78.6% were obtained. In addition, the samples obtained at different carbonization temperatures were all highly stable over 50 cycles, with capacity retentions greater than 90%.

Kim, Jong Gu; Liu, Fei; Lee, Chul-Wee; Lee, Young-Seak; Im, Ji Sun

2014-08-01

38

Grain growth mechanism in boron doped polycrystalline silicon  

NASA Astrophysics Data System (ADS)

The mechanism of grain growth in heavily boron doped polycrystalline silicon has been studied for various boron concentrations, annealing times and annealing temperatures by proposing a kinetic model based on thermodynamical concepts. A computer simulation technique has been used to determine the grain boundary self-diffusion of silicon atoms. Our theoretical predictions have been compared with available experimental reports. This model has been extended to evaluate the grain size distribution in boron doped polysilicon for various dopant concentrations, annealing times and temperatures. The results are discussed in detail.

Kalainathan, S.; Dhanasekaran, R.; Ramasamy, P.

1990-10-01

39

Selecting boron fullerenes by cage-doping mechanisms.  

PubMed

So far, no boron fullerenes were synthesized: more compact sp(3)-bonded clusters are energetically preferred. To circumvent this, metallic clusters have been suggested by Pochet et al. [Phys. Rev. B 83, 081403(R) (2011)] as "seeds" for a possible synthesis which would topologically protect the sp(2) sector of the configuration space. In this paper, we identify a basic pentagonal unit which allows a balance between the release of strain and the self-doping rule. We formulate a guiding principle for the stability of boron fullerenes, which takes the form of an isolated filled pentagon rule (IFPR). The role of metallic clusters is then reexamined. It is shown that the interplay of the IFPR and the seed-induced doping breaks polymorphism and its related problems: it can effectively select between different isomers and reduce the reactivity of the boron shells. The balance between self and exterior doping represents the best strategy for boron buckyball synthesis. PMID:23676039

Boulanger, Paul; Morinière, Maxime; Genovese, Luigi; Pochet, Pascal

2013-05-14

40

Selecting boron fullerenes by cage-doping mechanisms  

NASA Astrophysics Data System (ADS)

So far, no boron fullerenes were synthesized: more compact sp3-bonded clusters are energetically preferred. To circumvent this, metallic clusters have been suggested by Pochet et al. [Phys. Rev. B 83, 081403(R) (2011)] as ``seeds'' for a possible synthesis which would topologically protect the sp2 sector of the configuration space. In this paper, we identify a basic pentagonal unit which allows a balance between the release of strain and the self-doping rule. We formulate a guiding principle for the stability of boron fullerenes, which takes the form of an isolated filled pentagon rule (IFPR). The role of metallic clusters is then reexamined. It is shown that the interplay of the IFPR and the seed-induced doping breaks polymorphism and its related problems: it can effectively select between different isomers and reduce the reactivity of the boron shells. The balance between self and exterior doping represents the best strategy for boron buckyball synthesis.

Boulanger, Paul; Morinière, Maxime; Genovese, Luigi; Pochet, Pascal

2013-05-01

41

Photoinduced doping in heterostructures of graphene and boron nitride.  

PubMed

The design of stacks of layered materials in which adjacent layers interact by van der Waals forces has enabled the combination of various two-dimensional crystals with different electrical, optical and mechanical properties as well as the emergence of novel physical phenomena and device functionality. Here, we report photoinduced doping in van der Waals heterostructures consisting of graphene and boron nitride layers. It enables flexible and repeatable writing and erasing of charge doping in graphene with visible light. We demonstrate that this photoinduced doping maintains the high carrier mobility of the graphene/boron nitride heterostructure, thus resembling the modulation doping technique used in semiconductor heterojunctions, and can be used to generate spatially varying doping profiles such as p-n junctions. We show that this photoinduced doping arises from microscopically coupled optical and electrical responses of graphene/boron nitride heterostructures, including optical excitation of defect transitions in boron nitride, electrical transport in graphene, and charge transfer between boron nitride and graphene. PMID:24727687

Ju, L; Velasco, J; Huang, E; Kahn, S; Nosiglia, C; Tsai, Hsin-Zon; Yang, W; Taniguchi, T; Watanabe, K; Zhang, Y; Zhang, G; Crommie, M; Zettl, A; Wang, F

2014-05-01

42

Synthesis and characterization of nitrogen-doped graphitic nanoribbons  

NASA Astrophysics Data System (ADS)

Nitrogen doping of carbon nanostructures such as nanotubes and graphene is a practical approach for tailoring their electronic and chemical properties. However, the doping of graphene nanoribbons still remains to be a challenge. Here we discuss a novel synthetic route to N-doped graphitic nanoribbons using chemical vapor deposition. The morphology of the new nanomaterial resembles the observed for the undoped graphitic nanoribbons, with particular differences specially at the ribbons' edges. We performed scanning and transmission electron microscopy as well as Raman and X-ray photoelectron spectroscopies in order to confirm the nitrogen presence within the nanoribbons. In addition, the electrical response for individual nanoribbons was obtained. We observed that N-doped nanoribbons exhibit a clear semiconductor-like behavior depending on the amount of nitrogen embedded in the hexagonal carbon network (undoped nanoribbons always showed a metallic response). These doped nanostructures could find applications in the fabrication of electronic devices.

Ortiz, Josue; Garcia, M. Luisa; Jia, Xiaoting; Martinez, Rafael; Pelagio, Miguel A.; Swanson, David; Elias, A. Laura; Gutierrez, Humberto; Rodriguez, Fernando; Munoz, Emilio; Dresselhaus, Mildred; Terrones, Humberto; Terrones, Mauricio

2012-02-01

43

Boron-doped back-surface fields using an aluminum-alloy process  

SciTech Connect

Boron-doped back-surface fields (BSF`s) have potentially superior performance compared to aluminum-doped BSF`s due to the higher solid solubility of boron compared to aluminum. However, conventional boron diffusions require a long, high temperature step that is both costly and incompatible with many photovoltaic-grade crystalline-silicon materials. We examined a process that uses a relatively low-temperature aluminum-alloy process to obtain a boron-doped BSF by doping the aluminum with boron. In agreement with theoretical expectations, we found that thicker aluminum layers and higher boron doping levels improved the performance of aluminum-alloyed BSF`s.

Gee, J.M.; Bode, M.D.; Silva, B.L.

1997-10-01

44

Boron fullerenes: From B80 to hole doped boron sheets  

Microsoft Academic Search

We demonstrate the existence of a family of stable boron fullerenes containing 80n2 atoms that is related to the family of 60n2 carbon icosahedral fullerene series and is compatible with the recently proposed stable boron sheets composed of triangular and hexagonal motifs. All electron density-functional calculations on the B320 , B720 , B1280 , and B2000 confirm their stability and

Rajendra R. Zope; Tunna Baruah; K. C. Lau; Amy Y. Liu; M. R. Pederson; B. I. Dunlap

2009-01-01

45

Boron-Doped Carbon Nanospaces for High-Capacity Hydrogen Storage  

Microsoft Academic Search

The Alliance for Collaborative Research in Alternative Fuel Technology (ALL-CRAFT, http:\\/\\/all-craft.missouri.edu) has been optimizing high surface area [>3,000 m2\\/g] activated carbon nanospaces for high capacity hydrogen storage. Boron-doped samples have been produced using solid, liquid, and vapor phase boron doping. The boron-doped samples were analyzed using sub-critical nitrogen adsorption to determine surface areas and the effect that boron-doping and annealing,

Matthew Beckner; Jacob Burress; Carlos Wexler; Zhi Yang; Fred Hawthorne; Peter Pfeifer

2009-01-01

46

Atomic hydrogen adsorption on lithium-doped graphite surfaces  

SciTech Connect

The effects of lithium doping of pristine and defective graphite surfaces on hydrogen adsorption are studied by the first-principles Plane-Wave Density Functional Theory. The surface defects are simulated by a single atomic vacancy. The DFT calculation is corrected for long-range effects through semi-empirical London terms for each constituent of the system. The lithium doping of the graphite surfaces notably reinforces hydrogen atom binding. Qualitative comparison with experimental results is given using the lithium 1s energy level shifts induced by the atomic vacancy and/or hydrogen trapping.

Allouche, Alain [CNRS/Univ. de Provence (France); Krstic, Predrag S [ORNL

2012-01-01

47

Boron and nitrogen-doped single-walled carbon nanotube  

NASA Astrophysics Data System (ADS)

Boron nitride semiconducting zigzag single-walled carbon nanotube (SWCNT), BcbNcnC, as a potential candidate for making nanoelectronic devices is investigated by first-principle full potential density functional theory (DFT). In contrast to the previous DFT calculations, where just one boron and nitrogen doping configuration is considered, here for the average over all possible configurations density of states is calculated in terms of boron and nitrogen concentrations. For example in many body techniques (MBTs) [R. Moradian, Phys. Rev. B 89 (2004) 205425] it is found that semiconducting average gap, Eg, could be controlled by doping nitrogen and boron. But in contrast to MBTs where gap edge in the average density of states is sharp, the gap edge is smeared and impurity states appear in the SWCNT semiconducting gap.

Moradian, Rostam; Azadi, Sam

2006-10-01

48

Pairwise cobalt doping of boron carbides with cobaltocene  

SciTech Connect

We have performed Co K-edge x-ray absorption fine structure and x-ray absorption near edge structure measurements of Co-doped plasma enhanced chemical vapor phase deposition (PECVD) grown 'C{sub 2}B{sub 10}H{sub x}' semiconducting boron carbides, using cobaltocene. Cobalt does not dope PECVD grown boron carbides as a random fragment of the cobaltocene source gas. The Co atoms are fivefold boron coordinated (R=2.10{+-}0.02 A) and are chemically bonded to the icosahedral cages of B{sub 10}CH{sub x} or B{sub 9}C{sub 2}H{sub y}. Pairwise Co doping occurs, with the cobalt atoms favoring sites some 5.28{+-}0.02 A apart.

Ignatov, A. Yu.; Losovyj, Ya. B.; Carlson, L.; LaGraffe, D.; Brand, J. I.; Dowben, P. A. [Center for Advanced Microstructures and Devices, Louisiana State University, 6980 Jefferson Highway, Baton Rouge, Louisiana 70806 (United States); Air Force Institute of Technology, 2950 Hobson Way, Wright Patterson Air Force Base, Ohio 45433-7765 (United States); College of Engineering and Technology, N245 Walter Scott Engineering Center, 17th and Vine Streets, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0511 (United States); Department of Physics and Astronomy, Behlen Laboratory of Physics, University of Nebraska, P.O. Box 880111, Lincoln, Nebraska 68588-0111 (United States) and the Nebraska Center for Materials and Nanoscience, Behlen Laboratory of Physics, University of Nebraska, P.O. Box 880111, Lincoln, Nebraska 68588-0111 (United States)

2007-10-15

49

Inhibition of catalytic oxidation of carbon\\/carbon composites by boron-doping  

Microsoft Academic Search

The inhibition effect of high temperature boron-doping on the catalytic oxidation of carbon\\/carbon composites was investigated. Boron-doping at 2500°C was found to improve the oxidation resistance of catalyst-loaded composites. Evident inhibition mechanisms include the reduction of active site number by increasing the crystallite size and the site blockage by formed boron oxide. Boron-doping at less than 1.0wt.% was found to

Xianxian Wu; Ljubisa R. Radovic

2005-01-01

50

Nuclear reaction microanalysis of boron doped steels  

NASA Astrophysics Data System (ADS)

The microanalysis of trace amounts of boron has been carried out using a 1 ?m proton microbeam from the 3 MV single-ended electrostatic accelerator of TIARA facility, JAEA Takasaki. Steel specimens containing 20-100 ppm boron have been bombarded by 1.7 MeV proton beam for ?-ray detection and 1.32 MeV H2+ beam for ?-particles. The maps of boron distribution have been measured by detecting 428 keV ?-rays emitted from the 10B (p, ?'?) 7Be nuclear reaction and 3.7 MeV ?-particles from the 11B (p, ?) 8Be nuclear reaction. As a result of imaging, segregation of several micron sized boron precipitates could be clearly seen.

Shibata, H.; Kohno, Y.; Shibata, K.; Sato, T.; Oikawa, M.; Haga, J.; Sakai, T.

2007-07-01

51

Nucleosides and ODN electrochemical detection onto boron doped diamond electrodes  

Microsoft Academic Search

Boron doped diamond (BDD) is a promising material for electroanalytical chemistry due mainly to its chemical stability, its high electrical conductivity and to the large amplitude of its electroactive window in aqueous media. The latter feature allowed us to study the direct oxidation of the two electroactive nucleosides, guanosine and adenosine. The BDD electrode was first activated by applying high

Elodie Fortin; Jérôme Chane-Tune; Pascal Mailley; Sabine Szunerits; Bernadette Marcus; Jean-Pierre Petit; Michel Mermoux; Eric Vieil

2004-01-01

52

Electrochemical oxidation of benzene on boron-doped diamond electrodes  

Microsoft Academic Search

This work presents an electrochemical investigation of the benzene oxidation process in aqueous solution on boron-doped diamond (BDD) electrodes. Additionally, in order to determine the main products generated during the oxidation process, electrolysis and high performance liquid chromatography experiments were carried out. The complete degradation of this compound was performed aiming to a further application in waste water treatment. The

Robson T. S. Oliveira; Giancarlo R. Salazar-Banda; Mauro C. Santos; Marcelo L. Calegaro; Douglas W. Miwa; Sergio A. S. Machado; Luis A. Avaca

2007-01-01

53

APPLICATION OF BORON-DOPED DIAMOND ELECTRODES FOR WASTEWATER TREATMENT  

Microsoft Academic Search

Boron-doped diamond (BDD) thin film is a new electrode material that has received great attention recently because it possesses several technologically important characteristics such as an inert surface with low adsorption properties, remarkable corrosion stability, even in strong acidic media, and an extremely wide potential window in aqueous and non-aqueous electrolytes. Due to these properties, diamond electrodes are promising anodes

Marco Panizza; Enric Brillas; Christos Comninellis

54

Direct determination of boron in a cobalt-based alloy by graphite furnace-atomic absorption spectrometry  

Microsoft Academic Search

A matrix modifier composed of nickel and zirconium, and a graphite tube treated with zirconium solution were proposed for the determination of boron in cobalt-based alloys by graphite furnace-atomic absorption spectrometry. The effects of this matrix modifier and the treated graphite tube were studied, and the combination of 60 ?g of nickel and 20 ?g of zirconium as matrix modifier,

Benling Gong; Yongming Liu; Yuli Xu; Zhuanhe Li; Tiezheng Lin

1995-01-01

55

Concentric shelled and plate-like graphitic boron nitride nanoparticles produced by CO 2 laser pyrolysis  

NASA Astrophysics Data System (ADS)

The morphology of graphitic boron nitride nanometric particles produced from the reaction between ammonia and borontrichloride heated by a CO 2 laser is investigated by high resolution electron microscopy. A variety of roughly spherical particles are revealed, consisting of concentric graphitic shells and ranging in size from 20 to more than 100 nm and in shape from hollow to filled-to-the-center. This onion-like configuration is very similar to that observed in carbon materials. Another morphology made of stackings of a few perfectly flat graphitic sheets (10 to 50 layers, 50 nm in length) is developed after heat treatment.

Boulanger, L.; Andriot, B.; Cauchetier, M.; Willaime, F.

1995-03-01

56

Effects of Boron Doping on the Properties of Ultrananocrystalline Diamond Films  

NASA Astrophysics Data System (ADS)

Boron-doped ultrananocrystalline diamond (UNCD) films were fabricated on silicon substrates by microwave plasma chemical vapor deposition. UNCD films containing different concentrations of boron were prepared by using trimethylboron (B(CH3)3, TMB) as boron doping source and varying the amount of boron in the gas mixture from 0 ppm to 1000 ppm. The effects of boron doping on morphology, lattice parameter, phase composition, crystal size, and residual stress of UNCD films were investigated. No obvious change of the morphology was observed on doping with boron, and all the films had the UNCD crystal grains. Boron doping enhanced (111) growth. The preferred growth direction of the UNCD films was . Residual tensile stress was present in all the films, and increased with increasing the amount of boron in the gas mixture.

Yuan, Wen-Xiang; WU, Q. X.; Luo, Z. K.; Wu, H. S.

2014-04-01

57

First-principles study of atomic oxygen adsorption on boron-substituted graphite  

Microsoft Academic Search

Adsorption of atomic oxygen on boron-substituted graphite has been investigated using first-principles pseudopotential density functional method with the local density approximation. Different adsorption sites on periodic basal and prismatic surfaces have been investigated and compared. Generally, adsorption of atomic oxygen is most favorable on the zigzag surface and then armchair and basal surfaces. Mulliken population and density of states have

Qianku Hu; Qinghua Wu; Guang Sun; Xiaoguang Luo; Zhongyuan Liu; Bo Xu; Julong He; Yongjun Tian

2008-01-01

58

Electrical characterization of homoepitaxially deposited boron-doped diamond  

NASA Astrophysics Data System (ADS)

Homoepitaxial boron doped single crystal diamond films were deposited on 100 oriented Ib type synthetic diamond substrates via microwave plasma chemical vapor deposition. The gas phase chemistry of 6% methane/ hydrogen ratio and 5000 ppm of (B/C)gas was used for all samples deposited at different temperature from 900 to 1200^oC. The deposited films were characterized by FTIR, AFM, Raman spectroscopy and XRD Rocking curve measurement to assess doping level, surface morphology and crystalline quality. The high growth rate 16 micron per hour has been obtained by optimizing growth parameters such as microwave power, chamber pressure, and gas flow rate. The four-probe electrical resistance measurements on boron-doped samples were conducted between 14 K and 350 K and show competing effects of intrinsic and hoping conductivity.

Karna, Sunil; Vohra, Yogesh; Samudrala, Gopi; Tsoi, Georgi

2012-02-01

59

Direct determination of boron in a cobalt-based alloy by graphite furnace-atomic absorption spectrometry.  

PubMed

A matrix modifier composed of nickel and zirconium, and a graphite tube treated with zirconium solution were proposed for the determination of boron in cobalt-based alloys by graphite furnace-atomic absorption spectrometry. The effects of this matrix modifier and the treated graphite tube were studied, and the combination of 60 mug of nickel and 20 mug of zirconium as matrix modifier, and a graphite tube soaked with 10 g 1(-1) of zirconium solution were found to give the highest analytical sensitivity. The interference effects of major components (cobalt) and eight minor components (chromium, nickel, tungsten, iron, tantalum, molybdenum, titanium, aluminium and manganese) were studied. Boron in four cobalt-based alloys was determined by graphite furnace-atomic absorption spectrometry employing the proposed matrix modifier and the treated graphite tube, without the preseparation of matrix. The relative standard deviation was 3.3% for 0.048% of boron. A characteristic mass was 500 pg. PMID:18966371

Gong, B; Liu, Y; Xu, Y; Li, Z; Lin, T

1995-10-01

60

Chemical mechanical polishing of boron-doped polycrystalline silicon  

NASA Astrophysics Data System (ADS)

Chemical mechanical polishing (CMP) is a technique which helps to print a smaller depth of focus and smoother surface in micro fabrication industry. In this project, boron doped polysilicon is used as a fill material for Through Silicon Vias (TSV) creating a 3D package. It is shown that the presence of boron as dopant suppresses the polysilicon polish rate. To increase the polish rate, understanding the mechanism of polish rate retardation is essential. We believe that the electrical effects play the major role in this phenomenon and by reducing this effect we are able to increase the polish rate.

Pirayesh, Hamidreza; Cadien, Kenneth

2014-03-01

61

Study of the electronic properties of Li-intercalated nitrogen doped graphite  

Microsoft Academic Search

First-principles calculations are used to investigate the electronic properties of N-doped graphenes, including graphitic, pyridinic and pyrrolic nitrogens. The pristine, graphitic and pyridinic N-doped graphenes are also employed in stage-1 Li–graphite intercalation compounds and their electronic properties were investigated. The results indicate that the pristine graphene shows a zero-gap semiconducting behaviour, while the conductive behaviour in graphitic graphene changes to

Seifollah Jalili; Raheleh Vaziri

2011-01-01

62

Boron distribution in the subsurface region of heavily doped IIb type diamond  

NASA Astrophysics Data System (ADS)

For the first time investigations of the boron distribution in the subsurface region of HPHT boron-doped diamond that is promising for applications in electronics were carried out by X-ray photoelectron (XPS) and Raman spectroscopy. It was found from XPS data that the boron content decreased gradually more than one order of magnitude in depth of surface. The first-principle calculations have shown that the Raman polarizability in the crossed polarization configuration should increase considerably with boron doping. The Raman spectra from as-grown and polished surfaces of heavily boron-doped diamond are discussed in the context of theoretical results.

Mavrin, B. N.; Denisov, V. N.; Popova, D. M.; Skryleva, E. A.; Kuznetsov, M. S.; Nosukhin, S. A.; Terentiev, S. A.; Blank, V. D.

2008-05-01

63

Structures of Pt clusters on graphene doped with nitrogen, boron, and silicon: a theoretical study  

Microsoft Academic Search

The structures of Pt clusters on nitrogen-, boron-, silicon- doped graphenes are theoretically studied using density-functional theory. These dopants (nitrogen, boron and silicon) each do not induce a local curvature in the graphene and the doped graphenes all retain their planar form. The formation energy of the silicon-graphene system is lower than those of the nitrogen-, boron-doped graphenes, indicating that

Xian-Qi Dai; Ya-Nan Tang; Ya-Wei Dai; Yan-Hui Li; Jian-Hua Zhao; Bao Zhao; Zong-Xian Yang

2011-01-01

64

Magnetic molecules made of nitrogen or boron-doped fullerenes  

Microsoft Academic Search

By using density functional theory, we investigate the electronic structure of a fullerene C60 molecule doped with a nitrogen atom on its surface. We find that the impurity is strongly bonded to the carbon cage and the C60N molecule has a large magnetic moment of 3.00muB. We also study the adsorption of a boron atom on the fullerene. The bonding

Chih-Kai Yang

2008-01-01

65

Global and local superconductivity in boron-doped granular diamond.  

PubMed

Strong granularity-correlated and intragrain modulations of the superconducting order parameter are demonstrated in heavily boron-doped diamond situated not yet in the vicinity of the metal-insulator transition. These modulations at the superconducting state (SC) and at the global normal state (NS) above the resistive superconducting transition, reveal that local Cooper pairing sets in prior to the global phase coherence. PMID:24343908

Zhang, Gufei; Turner, Stuart; Ekimov, Evgeny A; Vanacken, Johan; Timmermans, Matias; Samuely, Tomás; Sidorov, Vladimir A; Stishov, Sergei M; Lu, Yinggang; Deloof, Bart; Goderis, Bart; Van Tendeloo, Gustaaf; Van de Vondel, Joris; Moshchalkov, Victor V

2014-04-01

66

Characterization of heavily boron-doped diamond films  

Microsoft Academic Search

A series of boron-doped polycrystalline diamond films grown by hot-filament-assisted chemical vapor deposition was studied with transmission electron microscopy (TEM), secondary-electron microscopy, Raman spectroscopy, Hall-effect and current-voltage measurements. The grain size of the diamond films decreased as the resistivity of the films decreased. A drastic change of the Raman spectra with the film resistivity was observed. The zone-center optical phonon

R. J. Zhang; S. T. Lee; Y. W. Lam

1996-01-01

67

Electroanalytical applications of boron-doped diamond microelectrode arrays  

Microsoft Academic Search

The electrochemical characteristics of a novel all diamond fabricated boron-doped diamond microelectrode array (BDD-MEA) are critically appraised. The voltammetric response of simple electron transfer processes has been investigated and found to generate sigmoidal voltammetric curves. Furthermore, the device has been utilized for various analytical applications including, the direct detection of 4-nitrophenol over the concentration range 1.8–9.2?M, manganese over the range

Nathan S. Lawrence; Markus Pagels; Andrew Meredith; Timothy G. J. Jones; Clive E. Hall; C. S. Jim Pickles; Herman P. Godfried; Craig E. Banks; Richard G. Compton; Li Jiang

2006-01-01

68

Electrochemical oxidation of aniline at boron-doped diamond electrodes  

Microsoft Academic Search

The electrochemical oxidation of aniline at boron-doped diamond (BDD) electrodes was investigated by cyclic voltammetry, steady-state polarization measurements and bulk electrolysis under potentiostatic control. It was found that acidic media is suitable for efficient electrochemical oxidation of aniline, because at low pH, the potential required for avoiding electrode fouling is lower than in neutral and alkaline media. The results of

M. Mitadera; N. Spataru; A. Fujishima

2004-01-01

69

Electrochemical oxidation of phenol at boron-doped diamond electrode  

Microsoft Academic Search

The electrochemical oxidation of phenol at synthetic boron-doped diamond thin film electrode (BDD) has been studied in acid media by cyclic voltammetry, chronoamperometry and bulk electrolysis. The results have shown that in the potential region of water stability (E<2.3 V vs. SHE) they can occur direct electron transfer reactions on BDD surface that results in electrode fouling due to the

J. Iniesta; P. A. Michaud; M. Panizza; G. Cerisola; A. Aldaz; Ch. Comninellis

2001-01-01

70

Boron doping of silicon by plasma source ion implantation  

Microsoft Academic Search

We have performed an extensive analysis of the structural and electrical characteristics of 150 and 200 mm Si wafers boron doped by low-energy (?0.5 to ?5 kV) plasma source ion implantation (PSII) from a BF3 plasma and subsequent rapid thermal annealing. The formation of shallow junctions (60 nm or less) required for 0.18 ?m device geometries has been verified by

R. J. Matyi; D. L. Chapek; D. P. Brunco; S. B. Felch; B. S. Lee

1997-01-01

71

Nitrogen-Doped Graphitic Nanoribbons: Synthesis, Characterization and Transport  

SciTech Connect

Nitrogen-doped graphitic nanoribbons (Nx-GNRs), synthesized by chemical vapor deposition (CVD) using pyrazine as a nitrogen precursor, are reported for the first time. Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) reveal that the synthesized materials are formed by multi-layered corrugated graphitic nanoribbons (GNRs) which in most cases exhibit the formation of curved graphene edges (loops). This suggests that during growth, nitrogen atoms promote loop formation; undoped GNRs do not form loops at their edges. Transport measurements on individual pure carbon GNRs exhibit a linear I-V (current-voltage) behavior, whereas Nx-GNRs show reduced current responses following a semiconducting-like behavior, which becomes more prominent for high nitrogen concentrations. To better understand the experimental findings, electron density of states (DOS), quantum conductance for nitrogen doped zigzag and armchair single-layer GNRs are calculated for different N doping concentrations using Density Functional Theory (DFT) and non-equilibrium Green functions. These calculations confirm the crucial role of nitrogen atoms in the transport properties, confirming that the nonlinear I-V curves are due to the presence of nitrogen atoms within the Nx-GNRs lattice that act as scattering sites. These characteristic Nx-GNRs transport could be advantageous in the fabrication of electronic devices including sensors in which metal-like undoped GNRs are unsuitable.

Jia, Xiaoting [Massachusetts Institute of Technology (MIT); Dresselhaus, M [Massachusetts Institute of Technology (MIT); Cruz Silva, Eduardo [ORNL; Munoz-Sandoval, E [Instituto de Microelectronica de Madrid (CNM, CSIC); Sumpter, Bobby G [ORNL; Terrones Maldonado, Humberto [ORNL; Terrones Maldonado, Humberto [ORNL; Lopez, Florentino [IPICyT

2013-01-01

72

Electronic structures and electron-phonon interactions of boron-doped carbon nanotube  

Microsoft Academic Search

We study the boron-doped single-walled carbon nanotubes using first-principles method based on the density functional theory. The total energy, band structure and density of states are calculated. From the formation energy of boron-doped nanotubes with different diameter, it is found that the narrower tube needs lower energy to substitute a carbon atom with a boron atom. Using the result of

Takashi Koretsune; Susumu Saito

2008-01-01

73

Efficient electron emitter utilizing boron-doped diamond tips with sp 2 content  

Microsoft Academic Search

A practical technique to enhance the electron emission of diamond tips by incorporation of boron dopant and sp2 content is reported. The effects of boron doping on electron field emission from an array of micro-patterned polycrystalline pyramidal diamond microtips with varying sp2 content have been systematically studied. The field emission characteristics of undoped and boron-doped diamond tips are significantly improved

A. Wisitsora-At; W. P Kang; J. L Davidson; Q Li; J. F Xu; D. V Kerns

1999-01-01

74

Mineralization of salicylic acid in acidic aqueous medium by electrochemical advanced oxidation processes using platinum and boron-doped diamond as anode and cathodically generated hydrogen peroxide  

Microsoft Academic Search

Solutions containing 164mgL?1 salicylic acid of pH 3.0 have been degraded by electrochemical advanced oxidation processes such as anodic oxidation, anodic oxidation with electrogenerated H2O2, electro-Fenton, photoelectro-Fenton and solar photoelectro-Fenton at constant current density. Their oxidation power has been comparatively studied in a one-compartment cell with a Pt or boron-doped diamond (BDD) anode and a graphite or O2-diffusion cathode. In

Elena Guinea; Conchita Arias; Pere Lluís Cabot; José Antonio Garrido; Rosa María Rodríguez; Francesc Centellas; Enric Brillas

2008-01-01

75

Degradation of 4,6-dinitro- o-cresol from water by anodic oxidation with a boron-doped diamond electrode  

Microsoft Academic Search

Anodic oxidation of 4,6-dinitro-o-cresol (DNOC) has been studied in a cell of 100ml with a boron-doped diamond anode and a graphite cathode, both of 3-cm2 area. Solutions containing up to approximately 240mgl?1 of compound in the pH range 2.0–12.0 have been treated at 100, 300 and 450mA between 15 and 50°C. Total mineralization is always achieved due to the great

Cristina Flox; José Antonio Garrido; Rosa María Rodríguez; Francesc Centellas; Pere-Lluís Cabot; Conchita Arias; Enric Brillas

2005-01-01

76

Tunneling spectroscopy and vortex imaging in boron-doped diamond.  

PubMed

We present the first scanning tunneling spectroscopy study of single-crystalline boron-doped diamond. The measurements were performed below 100 mK with a low temperature scanning tunneling microscope. The tunneling density of states displays a clear superconducting gap. The temperature evolution of the order parameter follows the weak-coupling BCS law with Delta(0)/kBTc approximately 1.74. Vortex imaging at low magnetic field also reveals localized states inside the vortex core that are unexpected for such a dirty superconductor. PMID:16606302

Sacépé, B; Chapelier, C; Marcenat, C; Kacmarcik, J; Klein, T; Bernard, M; Bustarret, E

2006-03-10

77

Direct cytochrome c electrochemistry at boron-doped diamond electrodes  

Microsoft Academic Search

Highly boron-doped diamond electrodes are characterized voltammetrically employing Ru(NH3)63+\\/2+, Fe(CN)63?\\/4?, benzoquinone\\/hydroquinone, and cytochrome c redox systems. The diamond electrodes, which are polished to nanometer finish, are initially `activated' electrochemically and then pretreated by oxidation, reduction, or polishing. All electrodes give reversible cyclic voltammetric responses for the reduction of Ru(NH3)63+ in aqueous solution.Redox systems other than Ru(NH3)63+\\/2+ show characteristic electrochemical behavior

Frank Marken; Christopher A Paddon; Dhinesh Asogan

2002-01-01

78

Development of supported boron-doping TiO 2 catalysts by chemical vapor deposition  

Microsoft Academic Search

In this study, supported nonmetal (boron) doping TiO2 coating photocatalysts were prepared by chemical vapor deposition (CVD) to enhance the activity under visible light irradiation\\u000a and avoid the recovering of TiO2. Boron atoms were successfully doped into the lattice of TiO2 through CVD, as evidenced from XPS analysis. B-doped TiO2 coating catalysts showed drastic and strong absorption in the visible

Xing-wang Zhang; Le-cheng Lei

2008-01-01

79

Effects of heteratom(boron or nitrogen) substitutional doping on the electronic properties of graphene nanoribbons  

Microsoft Academic Search

The electronic properties of graphene nanoribbons with heteratom(boron or nitrogen) substitutional doping at different sites are investigated by performing first-principles calculations based on density functional theory. The calculated results show that the boron substitutional doping changes the conducting characteristic of graphene nanoribbon to a half-metalic one. But the different nitrogen substitutional doping retain the half-metalic characteristic of graphene nanoribbon. It

Zhiyong Wang; Jianrong Xiao; Xinyu Li

80

Magnetic and electrical characterization of heavily boron-doped diamond  

SciTech Connect

For a heavily boron-doped diamond (BDD) film, temperature variations of the electrical conductivity {sigma} and magnetic susceptibility {chi} are reported. The room temperature {sigma} {approx_equal}143 ({omega}-cm){sup -1} corresponds to a carrier concentration {approx_equal}10{sup 3} ppm, and its temperature variation yields an activation energy E{sub a} {approx_equal}28 meV from 140 to 300 K and E{sub a}{approx_equal}0.88 meV from 40 to 80 K. It is argued that larger boron doping leads to lower magnitudes of E{sub a}. The {chi} vs. T data (1.8-350 K) fits the Curie-Weiss law, with the concentration of paramagnetic species {approx_equal}120 ppm and a diamagnetic susceptibility {approx_equal}-0.4x10{sup -6} emu/g Oe. The results obtained from the measurements of {sigma} and {chi} are discussed and compared.

Manivannan, A.; Underwood, S.; Morales, Erie H.; Seehra, M.S

2003-12-15

81

Structural, spectroscopic, and electrochemical characterization of boron-doped diamond films from different provenances  

SciTech Connect

Morphological, spectroscopic, and electrochemical aspects of boron-doped diamond (BDD) films grown on silicon surfaces originating from three different laboratories have been examined by atomic force microscopy (AF), Raman scattering, Auger electron spectroscopy, and cyclic voltammetry in polyethylene oxide LiClO{sub 4} electrolytes in ultrahigh vacuum. All specimens displayed AFM images characteristic of diamond and Raman spectra consistent with a wide range of boron concentrations (10{sup 19} to 10{sup 21} B atom/cm{sup 3}), with no evidence for the presence of gross graphitic impurities. The cyclic voltammetry of two of the specimens (denoted as GV2 and CWRU), however, showed features at potentials positive to lithium bulk deposition attributed to lithium-ion intercalation/deintercalation phenomena in non-diamond carbon present as a surface impurity, perhaps at the grain boundaries. This finding is consistent with earlier results for a specimen of type GV2 in aqueous electrolytes for which rates of heterogeneous electron transfer for certain redox couples were found higher than those for nominally clean BDD surfaces.

Li, L.F.; Totir, D.A.; Vinokur, N.; Miller, B.; Chottiner, G.; Evans, E.A.; Angus, J.C.; Scherson, D.A. [Case Western Reserve Univ., Cleveland, OH (United States)

1998-05-01

82

Boron-doped diamond heater and its application to large-volume, high-pressure, and high-temperature experiments.  

PubMed

A temperature of 3500 degrees C was generated using a diamond resistance heater in a large-volume Kawai-type high-pressure apparatus. Re and LaCrO(3) have conventionally been used for heaters in high-pressure studies but they cannot generate temperatures higher than 2900 degrees C and make in situ x-ray observations difficult due to their high x-ray absorption. Using a boron-doped diamond heater overcomes these problems and achieves stable temperature generation for pressure over 10 GPa. The heater starting material is a cold-compressed mixture of graphite with boron used to avoid the manufacturing difficulties due to the extreme hardness of diamond. The diamond heater was synthesized in situ from the boron-graphite mixture at temperature of 1600+/-100 degrees C and pressure of 20 GPa. By using the proposed technique, we have employed the diamond heater for high-temperature generation in a large-volume high-pressure apparatus. Achievement of temperatures above 3000 degrees C allows us to measure the melting points of the important constituents in earth's mantle (MgSiO(3), SiO(2), and Al(2)O(3)) and core (Fe and Ni) at extremely high pressures. PMID:19256662

Shatskiy, Anton; Yamazaki, Daisuke; Morard, Guillaume; Cooray, Titus; Matsuzaki, Takuya; Higo, Yuji; Funakoshi, Ken-ichi; Sumiya, Hitoshi; Ito, Eiji; Katsura, Tomoo

2009-02-01

83

Bimolecular porous supramolecular networks deposited from solution on layered materials: graphite, boron nitride and molybdenum disulphide.  

PubMed

A two-dimensional porous network formed from perylene tetracarboxylic diimide (PTCDI) and melamine may be deposited from solution on the surfaces of highly oriented pyrolytic graphite (HOPG), hexagonal boron nitride (hBN) and molybdenum disulphide (MoS2). Images acquired using high resolution atomic force microscopy (AFM) operating under ambient conditions have revealed that the network forms extended ordered monolayers (>1 ?m(2)) on HOPG and hBN whereas on MoS2 much smaller islands are observed. PMID:24969532

Korolkov, Vladimir V; Svatek, Simon A; Allen, Stephanie; Roberts, Clive J; Tendler, Saul J B; Taniguchi, Takashi; Watanabe, Kenji; Champness, Neil R; Beton, Peter H

2014-07-15

84

Metallographic evaluation of the reactions between boronated graphite and Fe-Ni-Cr alloys  

SciTech Connect

The compatibility of boronated graphite with alloy 800H and type 316 stainless steel was evaluated metallographically after exposures at 700 and 810/sup 0/C for up to 10,000 h. At 700/sup 0/C, the principal reaction with both alloys was limited oxidation. At 810/sup 0/C, three types of reactions were observed: localized reactions at sites where the B/sub 4/C particles were in contact with the alloys' surfaces, intergranular penetration (much more prevalent for alloy 800H), and carburization.

Tortorelli, P.F.; Mayotte, J.R.; Henson, T.J.; DeVan, J.H.

1984-01-01

85

Electronic properties of graphene nanoribbon doped by boron\\/nitrogen pair: a first-principles study  

Microsoft Academic Search

By using the first-principles calculations, the electronic properties of graphene nanoribbon (GNR) doped by boron\\/nitrogen (B\\/N) bonded pair are investigated. It is found that B\\/N bonded pair tends to be doped at the edges of GNR and B\\/N pair doping in GNR is easier to carry out than single B doping and unbonded B\\/N co-doping in GNR. The electronic structure

Xiao Jin; Yang Zhi-Xiong; Xie Wei-Tao; Xiao Li-Xin; Xu Hui; OuYang Fang-Ping

2012-01-01

86

B and N isolate-doped graphitic carbon nanosheets from nitrogen-containing ion-exchanged resins for enhanced oxygen reduction  

PubMed Central

B,N-codoped carbon nanostructures (BNCS) can serve as alternative low-cost metal-free electrocatalysts for oxygen reduction reactions (ORR). However, the compensation effect between the p- (B atoms) and n-type (N atoms) dopants would make the covalent boron-nitride (BN) easily formed during the synthesis of BNCS, leading to a unsatisfactory ORR activity. Therefore, it has been challenging to develop facile and rapid synthetic strategies for highly active BNCS without forming the direct covalent BN. Here, a facile method is developed to prepare B and N isolate-doped graphitic nanosheets (BNGS) by using iron species for saving N element and simultaneous doping the B element from nitrogen-containing ion-exchanged resins (NR). The resulting BNGS exhibits much more onset potential (Eonset) compared with the B-doped graphitic carbon nanosheets (BGS), N-doped graphitic carbon nanosheets (NGS), as well as B,N-codoped disorder carbon (BNC). Moreover, the BNGS shows well methanol tolerance propery and excellent stability (a minimal loss of activity after 5,000 potential cycles) compared to that of commercial Pt/C catalyst. The goog performance for BNGS towards ORR is attributed to the synergistic effect between B and N, and the well electrons transport property of graphitic carbon in BNGS.

Wang, Lei; Yu, Peng; Zhao, Lu; Tian, Chungui; Zhao, Dongdong; Zhou, Wei; Yin, Jie; Wang, Ruihong; Fu, Honggang

2014-01-01

87

B and N isolate-doped graphitic carbon nanosheets from nitrogen-containing ion-exchanged resins for enhanced oxygen reduction.  

PubMed

B,N-codoped carbon nanostructures (BNCS) can serve as alternative low-cost metal-free electrocatalysts for oxygen reduction reactions (ORR). However, the compensation effect between the p- (B atoms) and n-type (N atoms) dopants would make the covalent boron-nitride (BN) easily formed during the synthesis of BNCS, leading to a unsatisfactory ORR activity. Therefore, it has been challenging to develop facile and rapid synthetic strategies for highly active BNCS without forming the direct covalent BN. Here, a facile method is developed to prepare B and N isolate-doped graphitic nanosheets (BNGS) by using iron species for saving N element and simultaneous doping the B element from nitrogen-containing ion-exchanged resins (NR). The resulting BNGS exhibits much more onset potential (Eonset) compared with the B-doped graphitic carbon nanosheets (BGS), N-doped graphitic carbon nanosheets (NGS), as well as B,N-codoped disorder carbon (BNC). Moreover, the BNGS shows well methanol tolerance propery and excellent stability (a minimal loss of activity after 5,000 potential cycles) compared to that of commercial Pt/C catalyst. The goog performance for BNGS towards ORR is attributed to the synergistic effect between B and N, and the well electrons transport property of graphitic carbon in BNGS. PMID:24898033

Wang, Lei; Yu, Peng; Zhao, Lu; Tian, Chungui; Zhao, Dongdong; Zhou, Wei; Yin, Jie; Wang, Ruihong; Fu, Honggang

2014-01-01

88

Determination of boron in silicon-doped gallium arsenide by electrothermal atomic absorption spectrometry and ultraviolet-visible spectrophotometry.  

PubMed

Two methods have been developed for the determination of boron impurities in silicon-doped gallium arsenide (GaAs) for electronics. The first method employs the electrothermal atomic absorption spectrometry (ETAAS), the second, the UV-Vis molecular absorption spectrophotomety. In both cases the GaAs sample is decomposed with aqua regia (1+1). To prevent Ga(III) interference on the ETAAS determination of boron, a double extraction of the chlorogallic acid (HGaCl4) in diethyl ether is performed. To improve the overall ETAAS performance, the graphite tubes were pre-treated with iridium(III) and tungsten(IV). A mixed chemical modifier containing Ni(II), Sr(II) and citric acid was also used. The characteristic mass (m0) is 301 +/- 47 pg and the detection limit (3sB) is 2.4 microg g(-1). The classic UV-Vis spectrophotometric procedure using curcumin was also extended to the determination of boron in GaAs. By masking Ga(III) with EDTA and a preliminary extraction of boron with 2-ethyl-hexane 1,3-diol, performed on a semi-micro scale, a detection limit of 0.6 microg g(-1) was achieved. Both methods were applied to the analysis of two Si-doped GaAs samples which were suspected of being boron-contaminated. Results are compared with those obtained by direct analysis of the decomposed sample solution using the inductively coupled plasma atomic emission spectrometry (ICP-AES). PMID:12556028

Taddia, Marco; Cerroni, Maria Grazia; Morelli, Elio; Musiani, Andrea

2002-01-01

89

Hydrogen storage material and process using graphite additive with metal-doped complex hydrides  

Microsoft Academic Search

A hydrogen storage material having improved hydrogen absorbtion and desorption kinetics is provided by adding graphite to a complex hydride such as a metal-doped alanate, i.e., NaAlH.sub.4. The incorporation of graphite into the complex hydride significantly enhances the rate of hydrogen absorbtion and desorption and lowers the desorption temperature needed to release stored hydrogen.

Ragaiy Zidan; James A. Ritter; Armin D. Ebner; Jun Wang; Charles E. Holland

2008-01-01

90

Boron-doped diamond-like amorphous carbon as photovoltaic films in solar cell  

Microsoft Academic Search

In this paper, the photovoltaic feature of metal-boron carbide-silicon (MCS) solar cell was reported. The boron-doped diamond-like carbon thin film on n-silicon substrate has been prepared using arc-discharge plasma chemical vapor deposition (PCVD) technique. The conductivity and the resistivity of the film were measured by Bio-Rad Hall5500PC system to be p-type semiconductor and 3–12?cm\\/?, respectively. The boron content in the

Z. Q. Ma; B. X. Liu

2001-01-01

91

Quantification of Mercury in Flue Gas Emission using Boron-doped Diamond Electrochemistry.  

National Technical Information Service (NTIS)

In this project, we have attempted to develop a new technique utilizing Boron-doped diamond (BDD) films to electrochemically detect mercury dissolved in solution via the initial deposition of metallic mercury, followed by anodic linear sweep voltammetry i...

A. Manivannan M. S. Seehra

2002-01-01

92

Plasma Synthesized Doped Boron Nanopowder for MgB2 Superconductors  

Microsoft Academic Search

Under this program, a process to synthesize nano-sized doped boron powder by a plasma synthesis process was developed and scaled up from 20 gram batches at program start to over 200 grams by program end. Over 75 batches of boron nanopowder were made by RF plasma synthesis. Particle sizes were typically in the 20-200 nm range. The powder was synthesized

James V. Marzik

2012-01-01

93

Boron heavy doping for Si molecular beam epitaxy using a HBO2 source  

Microsoft Academic Search

Boron doping with a high carrier concentration has been realized in Si molecular beam epitaxy (MBE) using a HBO2 source with the usual Knudsen cell. Maximum carrier concentration has reached 6×1020 cm?3 at crucible temperatures of 900 °C. From a comparison between activation energy for vapor pressure and carrier concentration dependence on crucible temperature, it was concluded that boron evaporated

Toru Tatsumi; Hiroyuki Hirayama; Naoaki Aizaki

1987-01-01

94

Gold intercalation of boron-doped graphene on Ni(111): XPS and DFT study  

NASA Astrophysics Data System (ADS)

The intercalation of a graphene layer adsorbed on a metal surface by gold or other metals is a standard procedure. While it was previously shown that pristine, i.e., undoped, and nitrogen-doped graphene sheets can be decoupled from a nickel substrate by intercalation with gold atoms in order to produce quasi-free-standing graphene, we find the gold intercalation behavior for boron-doped graphene on a Ni(111) surface to be more complex: for low boron contents (2-5%) in the graphene lattice only partial gold intercalation occurs and for higher boron contents (up to 20%) no intercalation is observed. In order to understand this different behavior, a density functional theory investigation is carried out, comparing undoped as well as substitutional nitrogen- and boron-doped graphene on Ni(111). We identify the stronger binding of the boron atoms to the nickel substrate as the factor responsible for the different intercalation behavior in the case of boron doping. However, the calculations predict that this energetic effect prevents the intercalation process only for large boron concentrations and that it can be overcome for smaller boron coverages, in line with our x-ray photoelectron spectroscopy experiments.

Zhao, W.; Gebhardt, J.; Gotterbarm, K.; Höfert, O.; Gleichweit, C.; Papp, C.; Görling, A.; Steinrück, H.-P.

2013-11-01

95

Barrier-free substitutional doping of graphene sheets with boron atoms: Ab initio calculations  

Microsoft Academic Search

Using ab initio methods, we propose a simple and effective way to substitutionally dope graphene sheets with boron. The method consists of selectively exposing each side of the graphene sheet to different elements. We first expose one side of the membrane to boron while the other side is exposed to nitrogen. Proceeding this way, the B atoms will be spontaneously

Renato B. Pontes; A. Fazzio; Gustavo M. Dalpian

2009-01-01

96

Gold intercalation of boron-doped graphene on Ni(111): XPS and DFT study.  

PubMed

The intercalation of a graphene layer adsorbed on a metal surface by gold or other metals is a standard procedure. While it was previously shown that pristine, i.e., undoped, and nitrogen-doped graphene sheets can be decoupled from a nickel substrate by intercalation with gold atoms in order to produce quasi-free-standing graphene, we find the gold intercalation behavior for boron-doped graphene on a Ni(111) surface to be more complex: for low boron contents (2-5%) in the graphene lattice only partial gold intercalation occurs and for higher boron contents (up to 20%) no intercalation is observed. In order to understand this different behavior, a density functional theory investigation is carried out, comparing undoped as well as substitutional nitrogen- and boron-doped graphene on Ni(111). We identify the stronger binding of the boron atoms to the nickel substrate as the factor responsible for the different intercalation behavior in the case of boron doping. However, the calculations predict that this energetic effect prevents the intercalation process only for large boron concentrations and that it can be overcome for smaller boron coverages, in line with our x-ray photoelectron spectroscopy experiments. PMID:24056002

Zhao, W; Gebhardt, J; Gotterbarm, K; Höfert, O; Gleichweit, C; Papp, C; Görling, A; Steinrück, H-P

2013-11-01

97

Adsorption of hydrogen on boron-doped graphene: A first-principles prediction  

SciTech Connect

The doping effects of boron on the atomic adsorption of hydrogen on graphene have been investigated using density functional theory calculations. The hydrogen adsorption energies and electronic structures have been considered for pristine and B-doped graphene with the adsorption of hydrogen on top of carbon or boron atom. It is found that the B-doping forms an electron-deficient structure, and decreases the hydrogen adsorption energy dramatically. For the adsorption of hydrogen on top of other sites, similar results also have been found. These results indicate that the hydrogen storage capacity is improved by the doping of B atom.

Zhou, Yungang; Zu, Xiaotao T.; Gao, Fei; Nie, JL; Xiao, H. Y.

2009-01-01

98

Toward deep blue nano hope diamonds: heavily boron-doped diamond nanoparticles.  

PubMed

The production of boron-doped diamond nanoparticles enables the application of this material for a broad range of fields, such as electrochemistry, thermal management, and fundamental superconductivity research. Here we present the production of highly boron-doped diamond nanoparticles using boron-doped CVD diamond films as a starting material. In a multistep milling process followed by purification and surface oxidation we obtained diamond nanoparticles of 10-60 nm with a boron content of approximately 2.3 × 10(21) cm(-3). Aberration-corrected HRTEM reveals the presence of defects within individual diamond grains, as well as a very thin nondiamond carbon layer at the particle surface. The boron K-edge electron energy-loss near-edge fine structure demonstrates that the B atoms are tetrahedrally embedded into the diamond lattice. The boron-doped diamond nanoparticles have been used to nucleate growth of a boron-doped diamond film by CVD that does not contain an insulating seeding layer. PMID:24738731

Heyer, Steffen; Janssen, Wiebke; Turner, Stuart; Lu, Ying-Gang; Yeap, Weng Siang; Verbeeck, Jo; Haenen, Ken; Krueger, Anke

2014-06-24

99

Induction annealing and subsequent quenching : effect on the thermoelectric properties of boron-doped nanographite ensembles.  

SciTech Connect

Boron-doped nanographite ensembles (NGEs) are interesting thermoelectric nanomaterials for high temperature applications. Rapid induction annealing and quenching has been applied to boron-doped NGEs using a relatively low-cost, highly reliable, laboratory built furnace to show that substantial improvements in thermoelectric power factors can be achieved using this methodology. Details of the design and performance of this compact induction furnace as well as results of the thermoelectric measurements will be reported here.

Xie, M.; Lee, C. H.; Wang, J.; Yap, Y. K.; Bruno, P.; Gruen, D.; Singh, D.; Routbort, J.; Michigan Technological Univ.

2010-01-01

100

Room-temperature dissociative hydrogen chemisorption on boron-doped fullerenes  

Microsoft Academic Search

Using first-principles electronic structure calculations, we show that trapping-mediated dissociative chemisorption of H2 molecules may occur on boron-doped fullerenes. Employing the Polanyi-Wigner equation and the van't Hoff-Arrhenius law parameterized by the results of first-principles calculations, we find that a H2 molecule adsorbed on boron-doped fullerenes can be dissociated without additional catalysts. The dissociation occurs in ˜0.5ps at room temperature, which

Hoonkyung Lee; Jia Li; Gang Zhou; Wenhui Duan; Gunn Kim; Jisoon Ihm

2008-01-01

101

Structure and Mn 2+ adsorption properties of boron-doped goethite  

Microsoft Academic Search

Two kinds of boron-doped goethites were synthesized, one was called ad-B-goethite prepared by reacting the original goethite with borax solution and the other called oc-B-goethite prepared in the presence of boric acid solution. The goethites were characterized by IR and XRD. The IR bands of FeOHFe in-plane bending and free OH of the boron-doped goethites were weak compared with the

Shuijiao Liao; Juan Wang; Duanwei Zhu; Liying Ren; Jianwei Lu; Mingjian Geng; Alan Langdon

2007-01-01

102

Structural and electronic properties of boron-doped double-walled silicon carbide nanotubes  

Microsoft Academic Search

The effects of boron doping on the structural and electronic properties of (6,0)@(14,0) double-walled silicon carbide nanotube (DWSiCNT) are investigated by using spin-polarized density functional theory. It is found that boron atom could be more easily doped in the inner tube. Our calculations indicate that a Si site is favorable for B under C-rich condition and a C site is

Somayeh Behzad; Rostam Moradian; Raad Chegel

2010-01-01

103

Electrical Characteristics of Metal Contacts to Boron-Doped Diamond Epitaxial Film  

Microsoft Academic Search

Current-voltage characteristics have been obtained for various metal contacts formed on boron-doped diamond epitaxial film prepared on synthesized Ib diamond by the microwave plasma-assisted chemical vapor deposition method. Ti contacts and W contacts have exhibited good ohmic and Schottky properties, respectively. For the first time, we have fabricated Schottky diodes on boron-doped diamond epitaxial films using these contacts and investigated

Hiromu Shiomi; Hideaki Nakahata; Takahiro Imai; Yoshiki Nishibayashi; Naoji Fujimori

1989-01-01

104

Electroanalysis of lincomycin using boron-doped diamond thin film electrode applied to flow injection system  

Microsoft Academic Search

The electroanalysis of lincomycin was investigated using boron-doped diamond thin film (BDD) electrodes. First, the electrochemistry of lincomycin was studied by cyclic voltammetry as a function of pH of the solution, scan rate and the concentration of lincomycin. Comparison experiments were carried out using glassy carbon electrode. Boron-doped diamond thin film electrode provided well-resolved oxidation irreversible cyclic voltammogram. It was

Kanokporn Boonsong; Suchada Chuanuwatanakul; Nattakarn Wangfuengkanagul; Orawon Chailapakul

2005-01-01

105

Ultralow-voltage boron-doped diamond field emitter vacuum diode  

Microsoft Academic Search

A boron-doped diamond field emitter diode with ultralow turn-on voltage and high emission current is reported. The diamond field emitter diode structure with a built-in cap was fabricated using molds and electrostatic bonding techniques. The emission current versus anode voltage of the capped diamond emitter diode with boron doping, sp2 content, and vacuum thermal electric (VTE) treatment shows a very

W. P. Kang; A. Wisitsora-at; J. L. Davidson; D. V. Kerns

1998-01-01

106

Memory Window Improvement Effect in Boron-doped Si Nanocrystal Memory  

Microsoft Academic Search

Boron doped Si nanocrystals were found to be extremely effective to increase the memory window of nanocrystal memory for the first time. Boron-doped Si nanocrystals on thermally grown silicon have been fabricated at low temperature using the photo-chemical vapor deposition (photo-CVD) technique. Even at the low temperature, crystalline structure was successfully obtained by this method. With the reference of undoped

Keein Bang; Sangsoo Kim; Koeng Su Lim

2007-01-01

107

Annealing of Amorphous Diamond-like Carbon Films Doped with Boron  

Microsoft Academic Search

Amorphous hydrogenated diamond-like carbon (DLC) films have been prepared by the saddle-field glow discharge technique. The films were doped with boron from the gas phase during the deposition. Doping with boron has been proved to be controllable and electrically effective. The samples are p-type and exhibit a thermally activated conductivity in the temperature range 300-500 K. The data on hole

Shane Sawyer; Tatiana Allen; Franco Gaspari; Stefan Zukotynski

1999-01-01

108

Laser annealing of neutron irradiated boron-10 isotope doped diamond  

SciTech Connect

10B isotope doped p-type diamond epilayer grown by chemical vapor deposition on (110) oriented type IIa diamond single crystal substrate was subjected to neutron transmutation at a fluence of 2.4 9 1020 thermal and 2.4 9 1020 fast neutrons. After neutron irradiation, the epilayer and the diamond substrate were laser annealed using Nd YAG laser irradiation with wave length, 266 nm and energy, 150 mJ per pulse. The neutron irradiated diamond epilayer and the substrate were characterized before and after laser annealing using different techniques. The characterization techniques include optical microscopy, secondary ion mass spectrometry, X-ray diffraction, Raman, photoluminescence and Fourier Transform Infrared spectroscopy, and electrical sheet conductance measurement. The results indicate that the structure of the irradiation induced amorphous epilayer changes to disordered graphite upon laser annealing. The irradiated substrate retains the (110) crystalline structure with neutron irradiation induced defects.

Jagannadham, K. [North Carolina State University; Butler, J. E. [North Carolina State University

2011-01-01

109

Heavily boron-doped effect on the etch rates of single-crystal silicon in TMAH solutions  

Microsoft Academic Search

The purpose of this paper is to study the heavily boron-doped effect on the etch rates of boron-doped single-crystal silicon in different TMAH solutions. The boron atoms were heavily doped in single-crystal silicon by using diffusion process. We change the pre-deposition time and annealing time of diffusion process to form different concentration distributions. The samples were pre-deposited at 1100°C and

Yong-Yi Chen; Chung-Nan Chen; Wen-Chie Huang

2009-01-01

110

Structure and superconductivity of isotope-enriched boron-doped diamond  

SciTech Connect

Superconducting boron-doped diamond samples were synthesized with isotopes of {sup 10}B, {sup 11}B, {sup 13}C and {sup 12}C. We claim the presence of a carbon isotope effect on the superconducting transition temperature, which supports the 'diamond-carbon'-related nature of superconductivity and the importance of the electron-phonon interaction as the mechanism of superconductivity in diamond. Isotope substitution permits us to relate almost all bands in the Raman spectra of heavily boron-doped diamond to the vibrations of carbon atoms. The 500 cm{sup 01} Raman band shifts with either carbon or boron isotope substitution and may be associated with vibrations of paired or clustered boron. The absence of a superconducting transition (down to 1.6 K) in diamonds synthesized in the Co-C-B system at 1900 K correlates with the small boron concentration deduced from lattice parameters.

Thompson, Joe D [Los Alamos National Laboratory; Ekimov, E A [INSTIT OF HIGH PRESSURE; Sidorov, V A [INSTIT OF HIGH PRESSURE; Zoteev, A [MOSCOW SU; Lebed, Y [INST FOR NUCI RES; Stishov, S M [INST FOR HIGH PRESSURE

2008-01-01

111

Defect behavior in electron-irradiated boron- and gallium-doped silicon  

NASA Technical Reports Server (NTRS)

Production and anneal of defects in electron-irradiated, float-zone silicon solar cells were studied by DLTS. In boron- and gallium-doped, n+-p cells, dominant defects were due to the divacancy, carbon interstitial, and carbon complex. Results suggest that the DLTS peak normally ascribed to carbon complexes also involves gallium. For gallium- and, to a lesser extent, boron-doped samples, damaged lifetime shows substantial recovery only when the carbon-complex peak has annealed out at 400 C. In boron-doped, n+-p-p+ cells, a minority carrier trap (E1) was also observed by DLTS in cells with a boron p+, but not in those with an aluminum p+ back. A level at Ev + 0.31 eV appeared upon 150 C annealing (E1 out) in both p+ back types of samples.

Drevinsky, P. J.; Deangelis, H. M.

1982-01-01

112

Nitrogen-doped holey graphitic carbon from 2D covalent organic polymers for oxygen reduction.  

PubMed

Using covalent organic polymer pre-cursors, we have developed a new strategy for location control of N-dopant heteroatoms in the graphitic porous carbon, which otherwise is impossible to achieve with conventional N-doping techniques. The electrocatalytic activities of the N-doped holey graphene analogues are well correlated to the N-locations, showing possibility for tailoring the structure and property of N-doped carbon nanomaterials. PMID:24664790

Xiang, Zhonghua; Cao, Dapeng; Huang, Ling; Shui, Jianglan; Wang, Min; Dai, Liming

2014-05-28

113

Electronic Properties of Nitrogen\\/Boron-Doped Graphene Nanoribbons With Armchair Edges  

Microsoft Academic Search

Calculation of electronic structures has been performed for graphene nanoribbons with eight-armchair edges containing nitrogen or boron substitutional impurity by using ab initio density functional theory. It is found that the electronic structures of the doped graphene nanoribbon are different from those of doped carbon nanotubes. The impurity levels are autoionized, so that the relevant charge carriers occupy the conduction

Shan Sheng Yu; Wei Tao Zheng; Qing Jiang

2010-01-01

114

Graphitic electrodes modified with boron and nitrogen for electrochemical energy storage enhancement  

NASA Astrophysics Data System (ADS)

Electrodes based on carbon nanomaterials (carbon nanotubes or graphitic nanopetals) have been modified with boron (B) and nitrogen (N) through a facile microwave heating cycle. During the microwave heating, the electrodes are immersed in a precursor solution consisting of urea and boric acid dissolved in either water or methanol. After microwave heating and overnight vacuum drying, the electrodes are again heated in nitrogen to remove unreacted chemicals and to form CxBN. Hydrogen plasma was then used to remove any residual boron oxide from the surface of the electrodes. Carbon nanotubes modified with B and N exhibited higher lithium storage capacity as compared to pure carbon nanotube electrodes. We note that the modification appears to produce a highly unexpected and substantial cycle-to-cycle improvement in battery capacity as the electrode cycles through hundreds of charge-discharge iterations. This process can be applied to other carbon-based electrodes, which themselves are recognized for their high performance, to add further improvements.

Xiong, Guoping; Paul, Rajib; Reifenberger, Ron; Fisher, Timothy

2013-03-01

115

Electrochemically modulated liquid chromatography using a boron-doped diamond particle stationary phase  

PubMed Central

This paper reports on preliminary tests of the performance of boron-doped diamond powder (BDDP) as a stationary phase in electrochemically modulated liquid chromatography (EMLC). EMLC manipulates retention through changes in the potential applied (Eappl) to a conductive packing. Porous graphitic carbon (PGC) has routinely been utilized as a material in EMLC separations. Herein the utility of BDDP as a stationary phase in EMLC was investigated and its stability, both compositionally and microstructurally, relative to PGC was compared. The results show that BDDP is stable over a wide range of Eappl values (i.e., ?1.2 to +1.2 V vs. Ag/AgCl, sat’d NaCl). The data also reveal that electrostatics play a key role in the adsorption of the aromatic sulfonates on the BDDP stationary phase, and that these analytes are more weakly retained in comparison to the PGC support. The potential for this methodology to provide a means to advance the understanding of molecular adsorption and retention mechanisms on carbonaceous materials is briefly discussed.

Muna, Grace W.; Swope, Vernon M.; Swain, Greg M.; Porter, Marc D.

2011-01-01

116

Mineralization of paracetamol in aqueous medium by anodic oxidation with a boron-doped diamond electrode.  

PubMed

The degradation of 100ml of solutions with paracetamol (N-(4-hydroxyphenyl)acetamide) up to 1 g l(-1) in the pH range 2.0-12.0 has been studied by anodic oxidation in a cell with a boron-doped diamond (BDD) anode and a graphite cathode, both of 3-cm2 area, by applying a current of 100, 300 and 450 mA between 25 and 45 degrees C. Complete mineralization is always achieved due to the great concentration of hydroxyl radical (*OH) generated at the BDD surface, with release of NH4+ and NO3- ions. The mineralization rate is pH-independent, increases with increasing applied current and temperature, but decreases when drug concentration raises from 315 mg l(-1). Reversed-phase chromatography revealed a similar complex paracetamol decay in acid and alkaline media. Ion-exclusion chromatography allowed the detection of oxalic and oxamic acids as ultimate carboxylic acids. When the same solutions have been comparatively treated with a Pt anode, a quite poor mineralization is found because of the production of much lower *OH concentration. Under these conditions, the degradation rate is enhanced in alkaline medium and polymerization of intermediates is favored in concentrated solutions. Paracetamol can be completely destroyed with Pt and its kinetics follows a pseudo-first-order reaction with a constant rate independent of pH. PMID:15620731

Brillas, Enric; Sirés, Ignasi; Arias, Conchita; Cabot, Pere Lluís; Centellas, Francesc; Rodríguez, Rosa María; Garrido, José Antonio

2005-01-01

117

Focused ion beam fabrication of boron-doped diamond ultramicroelectrodes.  

PubMed

The fabrication of ultramicroelectrodes (UMEs) for analytical electrochemical applications has been explored, using boron-doped diamond as the active electrode material in an insulating coating formed by deposition of electrophoretic paint. Because of the rough nature of the diamond film, the property of such coatings that is normally exploited in the fabrication of UMEs, namely the tendency to retract automatically from sharp protrusions, cannot be used in the present instance. Instead focused ion beam (FIB) sputtering was employed to controllably produce UMEs with well-defined geometry, critical dimension of a few micrometers, and very thin insulating coatings. If the FIB machining is carried out at normal incidence to the diamond electrode surface, significant ion beam damage reduces the yield of successful electrodes. However, if a parallel machining geometry is employed, high yields of ultramicroelectrodes with a flat disk geometry can be obtained very reliably. The electrochemical properties of diamond UMEs are characterized. They show much lower background currents than the equivalent Pt or carbon fiber electrodes but more varied electrochemical response than macroscopic diamond electrodes. PMID:19545137

Hu, Jingping; Holt, Katherine B; Foord, John S

2009-07-15

118

Polyoxometalate-Modified Boron-Doped Diamond Electrodes  

NASA Astrophysics Data System (ADS)

Polyoxometalates were immobilized on a boron-doped diamond (BDD) surface modified by a photochemical modification method. The BDD surface was first modified with allyltriethylammonium bromide (ATAB) to form surface quaternary ammonium groups. The ATAB--BDD was then immersed in a phosphomolybdic acid (H3PMo12O40, denoted as PMo12) solution to fabricate PMo12-adsorbed ATAB--BDD (PMo12--ATAB--BDD). The electrostatic interaction between PMo12 and the quaternary ammonium group on ATAB--BDD is considered to be critical to the stable immobilization. Polyoxometalate-modified BDD was also fabricated from phosphonic-acid-terminated BDD. BDD was first modified with vinylphosphonic acid (VPA), followed by the reaction of the surface phosphonic acid groups with ammonium molybdate to generate a lacunary phosphomolybdic acid (PMox) group. Although the coverage of the PMox group on PMox--BDD was less than that of PMo12--ATAB--BDD, PMox--BDD was found to be more stable to potential cycling than PMo12--ATAB--BDD, indicating that covalent modification methods are effective for creating stable functional groups on diamond.

Kondo, Takeshi; Taniguchi, Yuichi; Yuasa, Makoto; Kawai, Takeshi

2012-09-01

119

In/extrinsic granularity in superconducting boron-doped diamond  

NASA Astrophysics Data System (ADS)

When charge carriers are introduced in diamond, e.g. by chemical doping with Boron (B), the C1-x?1021 cm), diamond becomes superconducting. Using microwave plasma-assisted chemical vapor deposition (MPCVD) we have prepared diamond:B thin films with critical offset temperatures T below 3 K. We have investigated the transport properties of these diamond:B thin films, which show pronounced granular effects. It turns out, that this granularity is both intrinsic as well as extrinsic. The extrinsic granularity is the effect of the growth method which needs to start from a seeding of the substrate with detonation nanodiamond, which acts as nucleation centers for further MPCVD growth of the film. In using SPM/STM techniques, we also observed intrinsic granularity, meaning that within physical grains, we observe also a strong intragrain modulation of the order parameter. As a consequence of these granularities, the transport properties show evidence of (i) strong superconducting fluctuations and (ii) Cooper pair tunneling and/or quasiparticle tunneling. The latter effects explain the observed negative magnetoresistance.

Willems, B. L.; Zhang, G.; Vanacken, J.; Moshchalkov, V. V.; Guillamon, I.; Suderow, H.; Vieira, S.; Janssens, S. D.; Haenen, K.; Wagner, P.

2010-10-01

120

Boron doped defective graphene as a potential anode material for Li-ion batteries.  

PubMed

Graphene with large surface area and robust structure has been proposed as a high storage capacity anode material for Li ion batteries. While the inertness of pristine graphene leads to better Li kinetics, poor adsorption leads to Li clustering, significantly affecting the performance of the battery. Here, we show the role of defects and doping in achieving enhanced adsorption without compromising on the high diffusivity of Li. Using first principles density functional theory (DFT) calculations, we carry out a comprehensive study of diffusion kinetics of Li over the plane of the defective structures and calculate the change in the number of Li atoms in the vicinity of defects, with respect to pristine graphene. Our results show that the Li-C interaction, storage capacity and the energy barriers depend sensitively on the type of defects. The un-doped and boron doped mono-vacancy, doped di-vacancy up to two boron, one nitrogen doped di-vacancy, and Stone-Wales defects show low energy barriers that are comparable to pristine graphene. Furthermore, boron doping at mono-vacancy enhances the adsorption of Li. In particular, the two boron doped mono-vacancy graphene shows both a low energy barrier of 0.31 eV and better adsorption, and hence can be considered as a potential candidate for anode material. PMID:24986702

Hardikar, Rahul P; Das, Deya; Han, Sang Soo; Lee, Kwang-Ryeol; Singh, Abhishek K

2014-07-16

121

Investigation of In-situ Boron-Doped Si Selective Epitaxial Growth by Comparison with Arsenic Doping  

NASA Astrophysics Data System (ADS)

In-situ boron-doped silicon selective epitaxial growth (SEG) was investigated by comparison with in-situ As-doped SEG. The dopant concentration and growth rate of the film grown under low pressure are high for B-doped SEG, while they are high under atmospheric pressure (AP) for As-doped SEG. This difference is interpreted to be due to the strong effects of HCl etching under AP and surface segregation of As. By optimizing the growth rate and temperature, we have successfully grown epitaxial Si layers with high B concentrations of 2.3 × 1020 atoms/cm3.

Ikuta, Tetsuya; Fujita, Shigeru; Iwamoto, Hayato; Kadomura, Shingo; Shimura, Takayoshi; Watanabe, Heiji; Yasutake, Kiyoshi

2008-04-01

122

Nitrogen-doped graphene nanosheets from bulk graphite using microwave irradiation.  

PubMed

Using simple microwave irradiation under the presence of sodium amide as a nitrogen source, preparation of nitrogen-doped graphene nanosheets has been successfully demonstrated. It is notable that exfoliation and nitrogen doping of graphite to nitrogen-doped graphene simultaneously occurred during the microwave irradiation within a minute, and nitrogen content of the doped graphene could reach up to 8.1%. It was also found that the binding configuration of nitrogen atom on graphitic layer consisted of various nitrogen-containing moieties such as pyridine-N, pyrrolic-N, and quaternary-N, and their composition was changed as a function of irradiation power. Although formation of undoped reduced graphene oxide by microwave irradiation resulted in slight increase of electrical conductivity because of the reductive recovery of oxidized graphite to graphene, nitrogen doping involved during irradiation induced much more notable increase of electrical conductivity more than 300 S cm(-1). Furthermore, nitrogen-doped graphene showed highly enhanced capacitive performance than that of undoped reduced graphene oxide, the specific capacitance of 200 F/g (current density of 0.5 A/g), which ascribes the pseudocapacitive effect from the incorporation of nitrogen atom on graphitic layer. PMID:24597537

Lee, Kwang Hoon; Oh, Jinwoo; Son, Jeong Gon; Kim, Heesuk; Lee, Sang-Soo

2014-05-14

123

Variation of the cell parameter of polycrystalline boron doped diamond films  

SciTech Connect

The lattice parameter of undoped and boron doped polycrystalline diamond films has been measured up to 8{times}10{sup 20} Bcm{sup {minus}3}. It varies slightly according to the three crystallographic directions [111], [220], and [311] investigated here. The cell parameters for the undoped films are within the published values for synthetic crystal and thin films. For the boron doped films, the cell parameter has a high expansion coefficient versus boron incorporation, with a mean value of {Delta}a/a=3{times}10{sup {minus}24} [B], ([B] in cm{sup {minus}3}), and a variation law in the [220] direction in striking agreement with a Russian work. The simplest Vegard model predicts a smaller variation, while both the deformation potential (but with a high deformation potential on the boron impurity band of +19.5 eV) and a defect model might explain the experimental results. {copyright} {ital 1997 American Institute of Physics.}

Brunet, F.; Deneuville, A.; Germi, P.; Pernet, M.; Gheeraert, E. [Centre National de la Recherche Scientifique, BP 166, 38042 Grenoble Cedex 9 (France)] [Centre National de la Recherche Scientifique, BP 166, 38042 Grenoble Cedex 9 (France)

1997-02-01

124

Electronic properties of graphene nanoribbon doped by boron/nitrogen pair: a first-principles study  

NASA Astrophysics Data System (ADS)

By using the first-principles calculations, the electronic properties of graphene nanoribbon (GNR) doped by boron/nitrogen (B/N) bonded pair are investigated. It is found that B/N bonded pair tends to be doped at the edges of GNR and B/N pair doping in GNR is easier to carry out than single B doping and unbonded B/N co-doping in GNR. The electronic structure of GNR doped by B/N pair is very sensitive to doping site besides the ribbon width and chirality. Moreover, B/N pair doping can selectively adjust the energy gap of armchair GNR and can induce the semimetal—semiconductor transmission for zigzag GNR. This fact may lead to a possible method for energy band engineering of GNRs and benefit the design of graphene electronic device.

Xiao, Jin; Yang, Zhi-Xiong; Xie, Wei-Tao; Xiao, Li-Xin; Xu, Hui; OuYang, Fang-Ping

2012-02-01

125

Electronic structure of boron doped diamond: An x-ray spectroscopic study  

NASA Astrophysics Data System (ADS)

The valence and conduction band electronic structure of boron-doped diamond has been measured using soft x-ray emission and absorption spectroscopy. The experimental results reveal p-type doping in the diamond film through the appearance of states in the band-gap. Structure distortion was observed around the doping center, while the long range order of the diamond structure remains. A chemically shifted C 1s level explains why one of the absorption features seems to appear below the valence band maximum. An excitonic feature was observed in the boron-doped diamond, similar to that observed in pure diamond, indicating that the exciton binding energy remains the same upon B-doping.

Glans, P.-A.; Learmonth, T.; Smith, K. E.; Ferro, S.; De Battisti, A.; Mattesini, M.; Ahuja, R.; Guo, J.-H.

2013-04-01

126

Electrochemically induced surface modifications of boron-doped diamond electrodes: an X-ray photoelectron spectroscopy study  

Microsoft Academic Search

The activity of diamond electrodes depends on the chemical state of the diamond surface, and the present work is focussed on understanding how chemical changes either produced in situ electrochemically, or by ex situ plasma treatments, influence the electrochemical properties. Conductive boron-doped diamond electrodes were produced by depositing adherent boron-doped diamond films on tungsten substrates using a hot filament reactor

Christiaan H. Goeting; Frank Marken; Aurora Gutiérrez-Sosa; Richard G. Compton; John S. Foord

2000-01-01

127

Metal-insulator transition and superconductivity in boron-doped diamond  

Microsoft Academic Search

We report on a detailed analysis of the transport properties and superconducting critical temperatures of boron-doped diamond films grown along the {100} direction. The system presents a metal-insulator transition (MIT) for a boron concentration (nB) on the order of nc˜4.5×1020cm-3 , in excellent agreement with numerical calculations. The temperature dependence of the conductivity and Hall effect can be well described

T. Klein; P. Achatz; J. Kacmarcik; C. Marcenat; F. Gustafsson; J. Marcus; E. Bustarret; J. Pernot; F. Omnes; Bo E. Sernelius; C. Persson; A. Ferreira da Silva; C. Cytermann

2007-01-01

128

Barrierless procedure for substitutionally doping graphene sheets with boron atoms: ab initio calculations  

Microsoft Academic Search

Using ab initio methods, we propose a simple and effective way to\\u000asubstitutionally dope graphene sheets with Boron. The method consists of\\u000aselectively exposing each side of the graphene sheet to different elements. We\\u000afirst expose one side of the membrane to Boron, while the other side is exposed\\u000ato Nitrogen. Proceeding this way, the B atoms will be spontaneously

Renato B. Pontes; A. Fazzio; Gustavo M. Dalpian

2008-01-01

129

Boron doping effects in electrochromic properties of NiO films prepared by sol-gel  

SciTech Connect

In this paper, NiO films doped with B{sub 2}O{sub 3} were first prepared by sol-gel. The effects of boron content on the structure and electrochromic properties of NiO films were studied with X-ray diffraction (XRD), transmission electron microscopy (TEM), cyclic voltammetric (CV) and UV-vis spectrophotometer, respectively. In addition, the roughness and phase of the bleached/colored were studied by atom force microscopy (AFM). B-doped prevent the crystallization of the films. The colored state transmittance could be significantly lowered when the boron added. The NiO film doped with boron exhibited a noticeable electrochromism with a variation of transmittance up to {proportional_to}60% at the wavelength range of 300-500 nm. (author)

Lou, Xianchun; Zhao, Xiujian; He, Xin [Key Laboratory of Silicate Materials Science and Engineering, Wuhan University of Technology, Ministry of Education, 122 Luoshi Road, Hongshan District, Wuhan, Hubei 430070 (China)

2009-12-15

130

Electronic and structural properties of Au-doped zigzag boron nitride nanotubes: A DFT study  

NASA Astrophysics Data System (ADS)

In this paper, structural and electronic properties of zigzag single-walled boron nitride nanotubes are investigated within density functional theory by adding one gold atom as an impurity. One boron and one nitrogen atoms are substituted by one gold atom separately. Calculations show that the substitution of Au atom on boron atom turns the BNNT into a p-type semiconductor with a band gap of 2.435 eV. On the other hand, doping the Au atom on N site diminishes the pristine BNNT gap to 3.905 eV.

Bagheri, Mosahhar; Bahari, Ali; Amiri, Masoud; Dehbandi, Behnam

2014-07-01

131

Boron Nitride Thin Films Grown on Graphitized 6H-SiC Substrates by Metalorganic Vapor Phase Epitaxy  

NASA Astrophysics Data System (ADS)

The growth of thin boron nitride (BN) films on graphitized 6H-SiC substrates was investigated in an attempt to reduce the large lattice mismatch between 6H-SiC and BN, which would improve the three-dimensional ordering in BN thin films grown by metalorganic vapor phase epitaxy (MOVPE). BN thin films were grown by low-pressure (300 Torr) MOVPE using triethylboron and ammonia on graphitized 6H-SiC substrates with surfaces displaying (1× 1) reconstruction as determined by low energy electron diffraction (LEED). The (1× 1) surfaces were formed by annealing at 1500 °C in ultrahigh vacuum with a base pressure of 10-10 Torr. The LEED patterns showed that the surfaces were covered with single-crystal graphite several monolayers thick. X-ray diffraction revealed that the c-axis lattice constant of the BN was 6.72 Å, which is close to the 6.66 Å of bulk hexagonal BN. In contrast, BN films grown on non-graphitized 6H-SiC substrates by MOVPE under the same conditions were mostly amorphous. Use of a graphitized 6H-SiC substrate covered with graphite several monolayers thick improves the degree of three-dimensional ordering in BN thin films grown by MOVPE.

Kobayashi, Yasuyuki; Hibino, Hiroki; Nakamura, Tomohiro; Akasaka, Tetsuya; Makimoto, Toshiki; Matsumoto, Nobuo

2007-04-01

132

Structural and electronic properties of boron-doped double-walled silicon carbide nanotubes  

NASA Astrophysics Data System (ADS)

The effects of boron doping on the structural and electronic properties of (6,0)@(14,0) double-walled silicon carbide nanotube (DWSiCNT) are investigated by using spin-polarized density functional theory. It is found that boron atom could be more easily doped in the inner tube. Our calculations indicate that a Si site is favorable for B under C-rich condition and a C site is favorable under Si-rich condition. Additionally, B-substitution at either single carbon or silicon atom site in DWSiCNT could induce spontaneous magnetization.

Behzad, Somayeh; Moradian, Rostam; Chegel, Raad

2010-12-01

133

Annealing of Amorphous Diamond-like Carbon Films Doped with Boron  

NASA Astrophysics Data System (ADS)

Amorphous hydrogenated diamond-like carbon (DLC) films have been prepared by the saddle-field glow discharge technique. The films were doped with boron from the gas phase during the deposition. Doping with boron has been proved to be controllable and electrically effective. The samples are p-type and exhibit a thermally activated conductivity in the temperature range 300-500 K. The data on hole concentration and mobility obtained from Hall effect measurements will be presented. Changes in transport properties of the samples resulted from annealing in vacuum at different temperatures will be discussed.

Sawyer, Shane; Allen, Tatiana; Gaspari, Franco; Zukotynski, Stefan

1999-11-01

134

Half-Metallic Ferromagnetism in Transition-Metal Doped Boron Nitride Nanotubes  

Microsoft Academic Search

We have studied zig-zag boron nitride (BN) nanotubes doped with the Ni\\u000ahexagonal-closepacked nanowire. The doped BN nanotubes are ferromagnetic metals\\u000awith substantial magnetism. Some special magnetic properties resulting from the\\u000ainteraction between the Ni nanowire and BN nanotubes are found. The Ni doped\\u000aBN(9,0) nanotube shows semi-half-metallic behavior, which could become\\u000ahalf-metallic after doping electrons more than 1.4 e\\/unit

H. J. Xiang; Jinlong Yang; J. G. Hou; Qingshi Zhu

2004-01-01

135

Adsorption of formaldehyde molecule on the pristine and silicon-doped boron nitride nanotubes  

NASA Astrophysics Data System (ADS)

The adsorption of formaldehyde (HCOH) molecule on the pristine and silicon-doped (Si-doped) single-walled (8, 0) boron nitride nanotubes (BNNTs) is investigated using density functional theory (DFT) calculations. Compared with the weak physisorption on the pristine BNNT, the HCOH molecule presents strong chemisorption on both silicon-substituted boron defect site and silicon-substituted nitrogen defect site of the BNNT, as indicated by the calculated geometrical structures and electronic properties for these systems. It is suggested that the Si-doped BNNT presents high sensitivity to toxic HCOH. Based on calculated results, the Si-doped BNNT is expected to be a potential novel sensor for detecting the presence of HCOH.

Wang, Ruoxi; Zhu, Rongxiu; Zhang, Dongju

2008-12-01

136

Oxygen Molecule Adsorption and Dissociation on Boron-doped Fullerene BC59  

NASA Astrophysics Data System (ADS)

We studied the oxygen molecule adsorption and dissociation on boron-doped fullerene (B-C59) from first principles spin polarized density functional theory method simulation. The results show that O2 molecule can be adsorbed and partially reduced on the Pauling sites of B-C59. The results are compared with those of nitrogen-doped fullerene (N-C59). From the comprehensive simulation results, some implications in catalyst application are given.

Yang, Shizhong; Zhao, Lei; Gao, Feng; Zhao, Guang-Lin; Khosravi, Ebrahim; Bagayoko, Diola

2013-03-01

137

Transport properties of boron-doped single-walled silicon carbide nanotubes  

Microsoft Academic Search

The doped boron (B) atom in silicon carbide nanotube (SiCNT) can substitute carbon or silicon atom, forming two different structures. The transport properties of both B-doped SiCNT structures are investigated by the method combined non-equilibrium Green’s function with density functional theory (DFT). As the bias ranging from 0.8 to 1.0V, the negative differential resistance (NDR) effect occurs, which is derived

Y. T. Yang; R. X. Ding; J. X. Song

2011-01-01

138

The electrochemical activity of boron-doped polycrystalline diamond thin film electrodes  

SciTech Connect

The electrochemical activity of [open quotes]as grown[close quotes] boron-doped polycrystalline diamond thin film electrodes has been studied using cyclic voltammetry, chronoamperometry, and ac impedance without external illumination. The resistivity of these materials after doping is ca. 10 ohm-cm. The diamond electrodes possess a low double layer capacitance and a relatively high polarization resistance toward surface oxidation. Slow electrode kinetics are observed for Fe(CN)[sub 6][sup 3[minus]/4[minus

Swain, G.M.; Ramesham, R. (Auburn Univ., AL (United States))

1993-02-15

139

Electronic properties of boron and nitrogen doped graphene nanoribbons and its application for graphene electronics  

Microsoft Academic Search

On the basis of density functional theory calculations, we have systematically investigated the electronic properties of armchair-edge graphene nanoribbons (GNRs) doped with boron (B) and nitrogen (N) atoms. B (N) atoms could effectively introduce holes (electrons) to GNRs and the system exhibits p- (n-) type semiconducting behavior after B (N) doping. According to the electronic structure calculations, Z-shape GNR-based field

Bing Huang

2011-01-01

140

Functionalization of Boron and Nitrogen-Doped Graphene and Carbon Nanotubes: An Ab Initio Study  

Microsoft Academic Search

We study the mechanism of covalent functionalization of boron (B) and nitrogen (N) doped graphene and carbon nanotubes by carboxyl (COOH) groups. Our calculations are carried out using density functional theory combined with the generalized gradient approximation for the exchange-correlation functional. The binding energies and equilibrium geometries of carboxylated B\\/N-doped graphene sheets and carbon nanotubes are examined in cases of

Nabil Al-Aqtash; Igor Vasiliev

2010-01-01

141

Resonance of graphene nanoribbons doped with nitrogen and boron: a molecular dynamics study  

PubMed Central

Summary Based on its enticing properties, graphene has been envisioned with applications in the area of electronics, photonics, sensors, bio-applications and others. To facilitate various applications, doping has been frequently used to manipulate the properties of graphene. Despite a number of studies conducted on doped graphene regarding its electrical and chemical properties, the impact of doping on the mechanical properties of graphene has been rarely discussed. A systematic study of the vibrational properties of graphene doped with nitrogen and boron is performed by means of a molecular dynamics simulation. The influence from different density or species of dopants has been assessed. It is found that the impacts on the quality factor, Q, resulting from different densities of dopants vary greatly, while the influence on the resonance frequency is insignificant. The reduction of the resonance frequency caused by doping with boron only is larger than the reduction caused by doping with both boron and nitrogen. This study gives a fundamental understanding of the resonance of graphene with different dopants, which may benefit their application as resonators.

Wei, Ye; Zhan, Haifei; Xia, Kang; Zhang, Wendong

2014-01-01

142

Boron Delta-Doping Dependence on Si\\/SiGe Resonant Interband Tunneling Diodes Grown by Chemical Vapor Deposition  

Microsoft Academic Search

Si\\/SiGe resonant interband tunnel diodes (RITD) were fabricated using CVD on 200-mm silicon wafers. The RITD devices consist of a $\\\\hbox{p}^{+}\\\\hbox{-i-n}^{+}$ structure with $\\\\delta$-doped quantum wells providing resonant interband tunneling through a nominally intrinsic Si\\/SiGe region. The vapor-phase doping technique was used to obtain abrupt degenerate doping profiles. The boron doping in the $\\\\delta$ -doped region was varied, and its

Anisha Ramesh; Tyler A. Growden; Paul R. Berger; Roger Loo; Wilfried Vandervorst; Bastien Douhard; Matty Caymax

2012-01-01

143

Growth and electrical characterisation of {delta}-doped boron layers on (111) diamond surfaces  

SciTech Connect

A plasma enhanced chemical vapor deposition protocol for the growth of {delta}-doping of boron in diamond is presented, using the (111) diamond plane as a substrate for diamond growth. AC Hall effect measurements have been performed on oxygen terminated {delta}-layers and desirable sheet carrier densities ({approx}10{sup 13} cm{sup -2}) for field-effect transistor application are reported with mobilities in excess of what would expected for equivalent but thicker heavily boron-doped diamond films. Temperature-dependent impedance spectroscopy and secondary ion mass spectroscopy measurements show that the grown layers have metallic-like electrical properties with high cut-off frequencies and low thermal impedance activation energies with estimated boron concentrations of approximately 10{sup 20} cm{sup -3}.

Edgington, Robert; Jackman, Richard B. [London Centre for Nanotechnology, and Department of Electronic and Electrical Engineering, University College London, 17-19 Gordon Street, London, WC1H 0AH (United Kingdom); Sato, Syunsuke; Ishiyama, Yuichiro; Kawarada, Hiroshi [Department of Electronic and Photonic Systems, Waseda University, Okubo 3-4-1, Shinjuku, Tokyo 169-8555 (Japan); Morris, Richard [Advanced SIMS Projects, Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom)

2012-02-01

144

Visible and Infra-red Light Emission in Boron-Doped Wurtzite Silicon Nanowires  

PubMed Central

Silicon, the mainstay semiconductor in microelectronic circuitry, is considered unsuitable for optoelectronic applications owing to its indirect electronic band gap, which limits its efficiency as a light emitter. Here we show the light emission properties of boron-doped wurtzite silicon nanowires measured by cathodoluminescence spectroscopy at room temperature. A visible emission, peaked above 1.5?eV, and a near infra-red emission at 0.8?eV correlate respectively to the direct transition at the ? point and to the indirect band-gap of wurtzite silicon. We find additional intense emissions due to boron intra-gap states in the short wavelength infra-red range. We present the evolution of the light emission properties as function of the boron doping concentration and the growth temperature.

Fabbri, Filippo; Rotunno, Enzo; Lazzarini, Laura; Fukata, Naoki; Salviati, Giancarlo

2014-01-01

145

Carbon doped boron nitride cages as competitive candidates for hydrogen storage materials.  

PubMed

By the incorporation of C atoms into (BN)(12) fullerene, our theoretical investigation shows that carbon doped boron nitride cages (BNC) can achieve a high hydrogen storage amount of 7.43 wt%, and dehydrogenation of the corresponding BNC hydrides (BNC(H)) is thermodynamically favored for practical applications of hydrogen energy, making BNC competitive candidates for hydrogen storage materials. PMID:20107638

Wu, H Y; Fan, X F; Kuo, Jer-Lai; Deng, Wei-Qiao

2010-02-14

146

Electrochemical degradation of anthraquinone dye Alizarin Red S by anodic oxidation on boron-doped diamond  

Microsoft Academic Search

The electrochemical oxidation of Anthraquinone dye (Alizarin Red S) has been studied on boron-doped diamond (BDD) electrodes on acid medium by cyclic voltammetry and bulk electrolysis. Galvanostatic electrolyses cause complex oxidation reactions that lead to the incineration of Alizarin Red S. The analyses of the chemical oxygen demand (COD) and the total organic carbon (TOC) during the galvanostatic electrolyses at

Ahmadi Mohamed Faouzi; Bensalah Nasr; Gadri Abdellatif

2007-01-01

147

Oxidation at boron doped diamond electrodes: an effective method to mineralise triazines  

Microsoft Academic Search

The electrochemical oxidation of cyanuric acid (CA) is examined by bulk electrolyses at boron doped diamond (BDD) electrode. The influence of operating conditions on the reaction trend is investigated and suitable conditions for oxidative demolition of CA are individuated. In particular a strong effect of current density and pH is evidenced, being neutral pH and high current the most favourable

Anna Maria Polcaro; Annalisa Vacca; Michele Mascia; Simonetta Palmas

2005-01-01

148

Conversion of carbon dioxide to peroxycarbonate at boron-doped diamond electrode  

Microsoft Academic Search

An electrochemical method has been developed for the efficient conversion of carbon dioxide to peroxycarbonate on a boron-doped diamond electrode under mild conditions. The process could be carried out in a batch operation as well as in a flow-system operation. The current efficiency for producing peroxycarbonate decreased significantly with increasing the temperature. A current efficiency of ca. 70% can be

Madhu Sudan Saha; Tsuneto Furuta; Yoshinori Nishiki

2004-01-01

149

Platinum particles deposited on synthetic boron-doped diamond surfaces. Application to methanol oxidation  

Microsoft Academic Search

Two methods have been used for the deposition of Pt particles on synthetic boron-doped diamond (BDD) surfaces: chemical deposition and electrodeposition under potentiostatic conditions. However, electrodeposition leads much higher platinum dispersion than chemical deposition. The mechanism of nucleation and growing of the electrodeposited platinum was investigated by means of chronoamperometric studies in acid medium. The electrodeposition on diamond surfaces shows

F. Montilla; E. Morallon; I. Duo; Ch. Comninellis; J. L. Vazquez

2003-01-01

150

Electrochemical detection of tricyclic antidepressant drugs by HPLC using highly boron-doped diamond electrodes  

Microsoft Academic Search

Boron-doped diamond (BDD) electrodes have been examined for the electrochemical detection of six tricyclic antidepressant drugs (TCAs): imipramine, desipramine, clomipramine, amitriptyline, nortriptyline, and doxepin. Cyclic voltammetry, flow injection analysis (FIA) and HPLC with electrochemical detection have been used to study the oxidation reactions and to detect the TCAs. At diamond electrodes, well-defined and highly reproducible voltammograms were obtained for all

T. A. Ivandini; B. V. Sarada; C. Terashima; T. N. Rao; D. A. Tryk; H. Ishiguro; Y. Kubota; A. Fujishima

2002-01-01

151

The electrooxidation of organic acids at boron-doped diamond electrodes  

Microsoft Academic Search

The electrooxidation of citric acid, malic acid, alanine and cysteine at boron-doped diamond (BDD) electrodes and glassy carbon (GC) electrodes was investigated by use of cyclic voltammetry. Well-defined, irreversible peaks were obtained for the oxidation of citric acid and cysteine. Malic acid and alanine exhibit discernible responses. This preliminary study has shown that BDD has better sensitivity than GC for

O Chailapakul; E Popa; H Tai; B. V Sarada; D. A Tryk; A Fujishima

2000-01-01

152

Boron-doped diamond electrodes and microelectrode-arrays for the measurement of sulfate and peroxodisulfate  

Microsoft Academic Search

Measurements of sulfate and peroxodisulfate concentrations with boron-doped diamond (BDD) electrodes and microelectrode array electrodes have been performed in various media. Diamond electrodes allow the measurement of sulfate on the anodic side of the electrochemical window through its oxidation into peroxodisulfate, and detection of peroxodisulfate on the cathodic side through the reverse reduction reaction. In all cases, current density was

Christophe Provent; Werner Haenni; Eduardo Santoli; Philippe Rychen

2004-01-01

153

Electrochemical incineration of oxalic acid at boron doped diamond anodes: Role of operative parameters  

Microsoft Academic Search

The electrochemical incineration of oxalic acid (OA) at boron doped diamond (BDD) anodes was investigated both theoretically and experimentally in order to find the influence of the operative parameters on the performances of the process. Polarization curves and chronoamperometric measurements indicate the probable occurrence of a direct electrochemical oxidation of OA at the surface of the BDD anode at low

Onofrio Scialdone; Alessandro Galia; Chiara Guarisco; Serena Randazzo; Giuseppe Filardo

2008-01-01

154

Electrochemical oxidation of benzoic acid at boron-doped diamond electrodes  

Microsoft Academic Search

The electrochemical oxidation of benzoic acid (BA) has been studied on boron-doped diamond electrodes on acid medium by cyclic voltammetry and bulk electrolysis. The results showed that in the potential region where the supporting electrolyte is stable, reactions occur, resulting in the loss of activity due to electrode fouling. Electrolysis at high anodic potentials in the region of electrolyte decomposition

F Montilla; P. A Michaud; E Morallón; J. L Vázquez; Ch Comninellis

2002-01-01

155

Indirect electrochemical oxidation of reverse osmosis membrane concentrates at boron-doped diamond electrodes  

Microsoft Academic Search

The treatment or disposal of concentrates generated from the filtrative treatment of water is rapidly becoming a factor of major environmental concern. This preliminary study discusses a novel approach in the abatement of reverse osmosis membrane retentate i.e. electrochemical oxidation. The recalcitrant organic constituents as well as the ammonia nitrogen in the retentate could be readily oxidised using boron-doped diamond

K. Van Hege; M. Verhaege; W. Verstraete

2002-01-01

156

Interaction of Pb and Cd during anodic stripping voltammetric analysis at boron-doped diamond electrodes  

Microsoft Academic Search

Highly boron-doped diamond (BDD) films were utilized for simultaneous electrochemical measurement of micromolar-level concentrations of Pb and Cd, and for the examination of their interactions. Differential pulse anodic stripping voltammetry (DPASV) was used for this detection. This approach can help to understand the possible detection of trace metals at BDD electrodes without the aid of mercury. These metals were found

A Manivannan; R Kawasaki; D. A Tryk; A Fujishima

2004-01-01

157

Advanced treatment of biologically pretreated coking wastewater by electrochemical oxidation using boron-doped diamond electrodes  

Microsoft Academic Search

Electrochemical oxidation is a promising technology to treatment of bio-refractory wastewater. Coking wastewater contains high concentration of refractory and toxic compounds and the water quality usually cannot meet the discharge standards after conventional biological treatment processes. This paper initially investigated the electrochemical oxidation using boron-doped diamond (BDD) anode for advanced treatment of coking wastewater. Under the experimental conditions (current density

Xiuping Zhu; Jinren Ni; Peng Lai

2009-01-01

158

Oxygen reduction on Au nanoparticle deposited boron-doped diamond films  

Microsoft Academic Search

Nanoparticle Au was deposited on as grown boron-doped diamond (BDD). The coverage and the morphology of the deposited Au particles were investigated by means of the linear sweep voltammeter and scanning electron microscopy (SEM). From SEM, the gold electrodeposited randomly as small spherical particles with an average diameter of 60nm. The applications of the as grown BDD film deposited by

Yanrong Zhang; Shunsuke Asahina; Sachio Yoshihara; Takashi Shirakashi

2003-01-01

159

Degradation of mixtures of phenols using boron doped diamond electrodes for wastewater treatment  

Microsoft Academic Search

A model is proposed for describing the electrochemical oxidation of multicomponent mixtures of organic compounds, when significant mineralization (i.e., combustion to CO2) of the compounds occurs. This is known to be the case of the degradation of many organic compounds on boron doped diamond (BDD) and other new electrocatalytic materials used as anodes. The proposed model predicts the variation of

A. Morão; A. Lopes; M. T. Pessoa de Amorim; I. C. Gonçalves

2004-01-01

160

Electrochemical degradation of the dye indigo carmine at boron-doped diamond anode for wastewaters remediation  

Microsoft Academic Search

Here we demonstrate that anodic oxidation with a boron-doped diamond (BDD) electrode can be applied to the remediation of wastewaters containing indigo carmine. This environmentally friendly method decontaminates completely acid and alkaline aqueous solutions of this dye. The degradation rate increases with increasing current and dye concentration. Indigo carmine is more rapidly removed in alkaline than in acid medium, but

Salah Ammar; Ridha Abdelhedi; Cristina Flox; Conchita Arias; Enric Brillas

2006-01-01

161

Highly-dispersed boron-doped graphene nanoribbons with enhanced conductibility and photocatalysis.  

PubMed

Highly-dispersed boron-doped graphene nanoribbons (B-GNRs), prepared by a simple vacuum activation method, exhibit p-type semiconductor properties and provide many more zigzag- and armchair-edges to facilitate control of the bandgap. B-GNRs are used for the photodegradation of Rhodamine B in order to demonstrate their excellent conductivity and photocatalytic activity. PMID:24825321

Xing, Mingyang; Fang, Wenzhang; Yang, Xiaolong; Tian, Baozhu; Zhang, Jinlong

2014-06-25

162

Development of boron-doped diamond thin-films as voltammetric and amperometric detectors  

Microsoft Academic Search

The utilization of boron-doped diamond thin-films for applications in electroanalysis was investigated. Voltammetric analysis in static solution, and amperometric detection coupled with flow injection analysis and HPLC were performed. The results were compared to those for glassy carbon. The electroactivity, the merit of detection figures, the adsorption of polar organic molecules, and the resistance to fouling were studied. Surface characterization

Jishou Xu

2000-01-01

163

Exohedral doping of single-walled boron nitride nanotube by atomic chemisorption  

NASA Astrophysics Data System (ADS)

The adsorption of atoms on the tube walls of (8,0) boron nitride nanotubes (BNNTs) has been studied using the density functional theory. Adsorption of either H or F (exohedral doping) on the B site imparts hole carrier conduction characteristics on the BNNT; however, co-adsorption on both of the B and N dimer pairs results in compensation.

Zhang, Jia; Loh, Kian Ping; Yang, Shuo Wang; Wu, Ping

2005-12-01

164

Electrochemical Modification of Boron-Doped Chemical Vapor Deposited Diamond Surfaces with Covalently Bonded Monolayers  

Microsoft Academic Search

Electrochemical reduction of phenyl diazonium salts in acetonitrile at boron-doped diamond electrodes yielded covalent bonding of aromatic groups to the sp 3 carbon surface. Diamond surfaces modified with nitrophenyl, trifluoromethylphenyl, and nitroa- zobenzene showed strong X-ray photoelectron spectroscopy (XPS) signals for surface nitrogen or fluorine, which were stable to exposure to air or solvents. Raman spectra of chemisorbed nitroazobenzene on

Tzu-Chi Kuo; Richard L. McCreery; Greg M. Swainb

1999-01-01

165

Boron concentration profiling by high angle annular dark field-scanning transmission electron microscopy in homoepitaxial ?-doped diamond layers  

NASA Astrophysics Data System (ADS)

To develop further diamond related devices, the concentration and spatial location of dopants should be controlled down to the nanometer scale. Scanning transmission electron microscopy using the high angle annular dark field mode is shown to be sensitive to boron doping in diamond epilayers. An analytical procedure is described, whereby local boron concentrations above 1020 cm-3 were quantitatively derived down to nanometer resolution from the signal dependence on thickness and boron content. Experimental boron local doping profiles measured on diamond p-/p++/p- multilayers are compared to macroscopic profiles obtained by secondary ion mass spectrometry, avoiding reported artefacts.

Araújo, D.; Alegre, M. P.; Piñero, J. C.; Fiori, A.; Bustarret, E.; Jomard, F.

2013-07-01

166

Boron concentration profiling by high angle annular dark field-scanning transmission electron microscopy in homoepitaxial ?-doped diamond layers  

SciTech Connect

To develop further diamond related devices, the concentration and spatial location of dopants should be controlled down to the nanometer scale. Scanning transmission electron microscopy using the high angle annular dark field mode is shown to be sensitive to boron doping in diamond epilayers. An analytical procedure is described, whereby local boron concentrations above 10{sup 20} cm{sup ?3} were quantitatively derived down to nanometer resolution from the signal dependence on thickness and boron content. Experimental boron local doping profiles measured on diamond p{sup ?}/p{sup ++}/p{sup ?} multilayers are compared to macroscopic profiles obtained by secondary ion mass spectrometry, avoiding reported artefacts.

Araújo, D.; Alegre, M. P.; Piñero, J. C. [Dpto Ciencia de los Materiales, Facultad de Ciencias, Universidad de Cádiz, 11510 Puerto Real (Cádiz) (Spain)] [Dpto Ciencia de los Materiales, Facultad de Ciencias, Universidad de Cádiz, 11510 Puerto Real (Cádiz) (Spain); Fiori, A.; Bustarret, E. [Institut Néel, CNRS-Université Joseph Fourier, 25 av. des Martyrs, 38042 Grenoble (France)] [Institut Néel, CNRS-Université Joseph Fourier, 25 av. des Martyrs, 38042 Grenoble (France); Jomard, F. [Groupe d'Etude de la Matière Condensée (GEMaC), UMR 8635 du CNRS, UVSQ, 45 av. des Etats-Unis, 78035 Versailles Cedex (France)] [Groupe d'Etude de la Matière Condensée (GEMaC), UMR 8635 du CNRS, UVSQ, 45 av. des Etats-Unis, 78035 Versailles Cedex (France)

2013-07-22

167

Properties of boron doped Tl-Ba-Ca-Cu-O superconductors  

SciTech Connect

The effects of boron doping on the formation and properties of the Tl-based superconductors have been studied. Up to 10 wt.% boron has been added to the oxides having the nominal composition, Tl{sub 1.8}Ba{sub 2}Ca{sub 2.2}Cu{sub 3}O{sub x}, by the usual solid-state reaction method. Boron additions in the range 0.8-1.0% increase the fraction of the Tl-2223 phase and significantly improve the critical temperature of the samples. Higher amounts of boron additions eliminate the Tl-2223 phase, reduce the fraction of Tl-2212 phase and cause separate non-superconducting phases to be formed. The formation of non-superconducting phases does not allow us to obtain pure Tl-2212 phase.

Kayed, Tarek S

2003-02-20

168

Effect of doping on electronic properties of double-walled carbon and boron nitride hetero-nanotubes  

NASA Astrophysics Data System (ADS)

The effect of boron nitride (BN) doping on electronic properties of armchair double-walled carbon and hetero-nanotubes is studied using ab initio molecular dynamics method. The armchair double-walled hetero-nanotubes are predicted to be semiconductor and their electronic structures depend strongly on the electronic properties of the single-walled carbon nanotube. It is found that electronic structures of BN-doped double-walled hetero-nanotubes are intermediate between those of double-walled boron nitride nanotubes and double-walled carbon and boron nitride hetero-nanotubes. Increasing the amount of doping leads to a stronger intertube interaction and also increases the energy gap.

Majidi, R.; Ghafoori Tabrizi, K.; Jalili, S.

2009-11-01

169

Direct visualization of boron dopant distribution and coordination in individual chemical vapor deposition nanocrystalline B-doped diamond grains  

NASA Astrophysics Data System (ADS)

The boron dopant distribution in individual heavily boron-doped nanocrystalline diamond film grains, with sizes ranging from 100 to 350 nm in diameter, has been studied using a combination of high resolution annular dark field scanning transmission electron microscopy and spatially resolved electron energy-loss spectroscopy. Using these tools, the boron distribution and local boron coordination have been determined. Quantification results reveal embedding of B dopants in the diamond lattice, and a preferential enrichment of boron at defective areas and twin boundaries. Coordination mapping reveals a distinct difference in coordination of the B dopants in ``pristine'' diamond areas and in defective regions.

Lu, Ying-Gang; Turner, Stuart; Verbeeck, Johan; Janssens, Stoffel D.; Wagner, Patrick; Haenen, Ken; Van Tendeloo, Gustaaf

2012-07-01

170

Synthesis, Characterization, and Thermoelectric Properties of Electrospun Boron-Doped Barium-Stabilized Bismuth-Cobalt Oxide Nanoceramics  

NASA Astrophysics Data System (ADS)

In this study, the boron-doped barium-stabilized bismuth cobalt oxide thermoelectric nanocrystalline ceramic powders were produced by the polymeric precursor technique. The powders were characterized by X-ray diffraction, scanning electron microscopy, and the physical properties measurement system. The X-ray diffraction results showed that these patterns have mixture of two phases as face-centered cubic and body-centered cubic. Values of the crystallite size, the dislocation density, and the microstrain were calculated by the Scherrer equation. According to these values, the crystallite size decreased from 60 to 51 nm with the boron addition in the boron-undoped and boron-doped samples, respectively. The scanning electron microscope results showed that nanograins are rarely seen in the boron-undoped samples, but nanograins turn into needle-like and layered structures with boron addition. The diameters distribution of nanofibers was calculated. The average diameter of the boron-doped sample is smaller than the boron-undoped sample. The physical properties measurement system values showed that the electrical and thermal conductivity, the Seebeck coefficient, and the figure of merit increased with the temperature rise for both samples. The boron-doping effect increased the electrical and thermal conductivity, decreased the Seebeck coefficient, and decreased the figure of merit.

Çinar, Emre; Koçyi?it, Serhat; Aytimur, Arda; Uslu, ?brahim; Akdemir, Ahmet

2014-05-01

171

Search for Superconductivity in Carbon Nanotubes Doped by Boron Ion Implantation  

NASA Astrophysics Data System (ADS)

The boron doping of single wall carbon nanotubes(CNT) by laser ablation synthesis has been reported to create superconducting B-CNTs with Tc's ranging from 12-19 Kelvin, depending on CNT inter-tube connection strength. We attempt to create boron doped multiwall CNT by ion implantation doping. Ion doping of boron(B) was performed at 60keV and 20keV, and low temperature transport combined with SQUID and ESR/LFMA was used in searching for SC. We have found that R(T) strongly depends on the metallic contact geometry. With thin film contacts on CNT sheets the R(T) shows no SC signatures, while when an Ag or Au paste penetrates the highly porous network of B doped multiwall CNT then R(T) drops and curvature changes are observed resembling SC transitions with Tc depending on B concentration and metallic electrode distances. We discuss these results in terms of possible SC in hybride "metal-CNT" system in which metal was predicted to supress phase fluctuation in one dimensional CNT network [1]. [4pt] [1] Erez Berg, Dror Orgad, and Steven A. Kivelson, Phys. Rev. B 78, 094509(2008)

Cornell, Nicholas; Kutsenov, Alex; Howard, Austin; Mayo, Nathaniel; Galstayan, Eduard; Kan Chu, Wei; Freyhardt, Herbert; Zakhidov, Anvar; Wang, Xuemei

2011-03-01

172

Carbon doping in molecular beam epitaxy of GaAs from a heated graphite filament  

NASA Technical Reports Server (NTRS)

Carbon doping of GaAs grown by molecular beam epitaxy has been obtained for the first time by use of a heated graphite filament. Controlled carbon acceptor concentrations over the range of 10 to the 17th-10 to the 20th/cu cm were achieved by resistively heating a graphite filament with a direct current power supply. Capacitance-voltage, p/n junction and secondary-ion mass spectrometry measurements indicate that there is negligible diffusion of carbon during growth and with postgrowth rapid thermal annealing. Carbon was used for p-type doping in the base of Npn AlGaAs/GaAs heterojunction bipolar transistors. Current gains greater than 100 and near-ideal emitter heterojunctions were obtained in transistors with a carbon base doping of 1 x 10 to the 19th/cu cm. These preliminary results indicate that carbon doping from a solid graphite source may be an attractive substitute for beryllium, which is known to have a relatively high diffusion coefficient in GaAs.

Malik, R. J.; Nottenberg, R. N.; Schubert, E. F.; Walker, J. F.; Ryan, R. W.

1988-01-01

173

Isolated boron and nitrogen sites on porous graphitic carbon synthesized from nitrogen-containing chitosan for supercapacitors.  

PubMed

Separated boron and nitrogen porous graphitic carbon (BNGC) is fabricated by a facile hydrothermal coordination/ZnCl2 -activation process from renewable and inexpensive nitrogen-containing chitosan. In this synthetic pathway, chitosan, which has a high nitrogen content, first coordinates with Fe(3+) ions to form chitosan-Fe that subsequently reacts with boric acid (boron source) to generate the BNGC precursor. After simultaneous carbonization and ZnCl2 activation followed by removal of the Fe catalyst, BNGC, containing isolated boron and nitrogen centers and having a high surface area of 1567?m(2) ?g(-1) and good conductivity, can be obtained. Results indicate that use of chitosan as a nitrogen-containing carbon source effectively prevents nitrogen atoms from direct combination with boron atoms. In addition, the incorporation of Fe(3+) ions not only endows BNGC with high graphitization, but also favors for nitrogen fixation. Remarkably, the unique microstructure of BNGC enables its use as an advanced electrode material for energy storage. As electrode material for supercapacitors, BNGC shows a high capacitance of 313?F?g(-1) at 1?A?g(-1) , and also long-term durability and coulombic efficiency of >99.5?% after 5000?cycles. Notably, in organic electrolytes, the energy density could be up to 50.1?Wh?kg(-1) at a power density of 10.5?kW?kg(-1) . The strategy developed herein opens a new avenue to prepare BNGC without inactive B?N bonds from commercially available chitosan for high-performance supercapacitors. PMID:24692324

Sun, Li; Fu, Yu; Tian, Chungui; Yang, Ying; Wang, Lei; Yin, Jie; Ma, Jing; Wang, Ruihong; Fu, Honggang

2014-06-01

174

Effect of boron doping on the surfaces of diamond thin films  

SciTech Connect

Auger and electron energy loss spectroscopies were used to study chemical and structural properties of as-grown surfaces of boron-doped diamond thin films prepared by microwave plasma-assisted chemical vapor deposition. Results are compared to surface properties of as-deposited undoped diamond thin films. As the boron level in the film increased energy losses associated with [pi] electron bonds ([ital sp][sup 2] sites) were enhanced at the surface. Similarly, the surface oxygen level of the films increased with increasing boron content. On the other hand the characteristic diamond Raman peak at 1332 cm[sup [minus]1] was narrower than in the undoped films and the broad band at about 1500 cm[sup [minus]1] associated with nondiamond carbon decreased. Surface morphology micrographs obtained from scanning electron microscopy (SEM) measurements indicated that the introduction of boron enhances the appearance of the (111) planes. Surface characterization together with the Raman and SEM results suggest that boron doping enhances surface reactivity resulting in increased adsorption of oxygen and carbonaceous species following the growth process. This behavior has implications on surface treatments necessary for device applications.

Shinar, R.; Leksono, M.; Shanks, H.R. (Microelectronics Research Center, Iowa State University, Ames, Iowa 50011 (United States))

1993-05-01

175

Nitrogen-doped, boron-doped and undoped multiwalled carbon nanotube/polymer composites in WORM memory devices  

NASA Astrophysics Data System (ADS)

We report the preparation of write-once-read-many times memory devices using composites of carbon nanotubes and poly(vinyl phenol) sandwiched between Al electrodes. Three types of nanotubes (undoped multiwalled carbon nanotubes, nitrogen-doped multiwalled carbon nanotubes and boron-doped multiwalled carbon nanotubes) are investigated for this application. The OFF to ON state switching threshold is only slightly dependent on nanotube type, but the ON/OFF current ratio depends on both nanotube type and concentration and varies up to 106, decreasing for nanotube concentrations larger than 0.50 wt% in the composite.

Mamo, Messai A.; Sustaita, Alan O.; Tetana, Zikhona N.; Coville, Neil J.; Hümmelgen, Ivo A.

2013-03-01

176

Influence of oxygen on defect production in electron-irradiated, boron-doped silicon  

NASA Technical Reports Server (NTRS)

Deep level transient spectroscopy (DLTS) measurements were made on float-zone and crucible-grown, boron-doped silicon irradiated with 1-MeV electrons. The minority carrier trap attributed to a boron-related state, was not seen in low-resistivity, float-zone silicon. However, a new majority carrier trap was observed in these samples. In the case of more lightly doped material the minority carrier trap was present, and its introduction rate was lower in float-zone than in crucible-grown silicon. For 1- and 10-ohm-cm float-zone material that was oxidized during processing, the introduction rates for this trap were comparable to those for crucible-grown silicon. This behavior indicates that the minority carrier trap involves oxygen and that it may be due to a boron-oxygen complex. The majority carrier trap seen in heavily doped, float-zone silicon may also involve boron but not oxygen. Observed trap concentrations suggest that oxygen content in the regions examined by DLTS is affected by processing techniques. Other differences were observed in defect production and annealing behavior of electron-irradiated, float-zone and crucible-grown silicon.

Deangelis, H. M.; Drevinsky, P. J.

1984-01-01

177

Post-synthesis carbon doping of individual multiwalled boron nitride nanotubes via electron-beam irradiation.  

PubMed

We report on post-synthesis carbon doping of individual boron nitride nanotubes (BNNTs) via in situ electron-beam irradiation inside an energy-filtering 300 keV high-resolution transmission electron microscope. The substitution of C for B and N atoms in the honeycomb lattice was demonstrated through electron energy loss spectroscopy, spatially resolved energy-filtered elemental mapping, and in situ electrical measurements. Substitutional C doping transformed BNNTs from electrical insulators to conductors. In comparison with the existing post-synthesis doping methods for nanoscale materials (e.g., ion implantation and diffusion), the discovered electron-beam-induced doping is a well-controlled, little-damaging, room-temperature, and simple strategy that is expected to demonstrate great promise for post-synthesis doping of diverse nanomaterials in the future. PMID:20836492

Wei, Xianlong; Wang, Ming-Sheng; Bando, Yoshio; Golberg, Dmitri

2010-10-01

178

graphite  

Microsoft Academic Search

Ultrasound treatment was used to study the decrease of the granulometry of graphite, due to the cavitation, which allows the erosion by separating grains. At a smaller scale, cavitation bubble implosion tears apart graphite sheets as shown by HRTEM, while HOand Hradicals produced from water sonolysis, generate oxidative and reductive reactions on these sheet fragments. Such reactions form smaller species,

Fabrice GUITTONNEAU; Abdesselam ABDELOUAS; Bernd GRAMBOW

179

Magnetic molecules made of nitrogen or boron-doped fullerenes  

Microsoft Academic Search

By using density functional theory we investigate the electronic structure of a fullerene C60 molecule doped with nitrogen atoms. We find that as long as the number of the impurity atoms is odd the doped fullerene turns magnetic, with its magnetic moment determined by the way the impurities are bonded with the carbon cage. For even number of impurities the

Chih-Kai Yang

2008-01-01

180

Influence of the boron precursor and drying method on surface properties and electrochemical behavior of boron-doped carbon gels.  

PubMed

Two series of B-doped carbon gels were prepared by the polymerization of resorcinol and formaldehyde in water using either boric acid or phenyl boronic acid as dopants. Both organic hydrogels were dried by four methods: supercritical, freeze, microwave oven, and vacuum oven drying. The effects of the boron precursor and drying method on the surface characteristics were studied by N2 and CO2 adsorption at -196 and 0 °C, respectively, immersion calorimetry into benzene and water, temperature-programmed desorption coupled with mass spectrometry, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Electrochemical characterization was carried out in a three-electrode cell, using Ag/AgCl as a reference electrode and a Pt wire as a counter electrode. The surface area obtained from immersion calorimetry into benzene was more realistic than that yielded by the Brunauer-Emmett-Teller (BET) equation. The hydrophobicity of the samples decreased linearly with a higher oxygen content. In addition, the oxygen content of the B-doped carbon gels increased linearly with a higher B content, and the interfacial or areal capacitance decreased linearly with a larger surface area. The capacitance was increased by B addition because of the pseudocapacitance effects of the higher oxygen content of the samples. The cryogel and vacuum-dried xerogel obtained from the boric acid series, Bc and Bv, respectively, showed the largest gravimetric and volumetric capacitances, around 140 F/g and 95 F/cm(3), respectively. PMID:24460055

Zapata-Benabihe, Zulamita; Moreno-Castilla, Carlos; Carrasco-Marín, Francisco

2014-02-18

181

Electronic and transport properties of boron and nitrogen doped graphene nanoribbons: an ab initio approach  

NASA Astrophysics Data System (ADS)

Graphene nanoribbons (GNRs) are expected to display extraordinary properties in the form of nanostructures. The effect of boron and nitrogen substitutional doping at four successive positions on electronic and transport properties of zigzag graphene nanoribbons (ZGNRs) is studied using spin-unpolarized density functional theory. It has been observed that the electronic structures of the doped ZGNRs are different from those of pristine ZGNRs. We have also calculated the transformation energy in the form of total energy. The substitutional boron atom at the nanoribbons edges suppresses the energy band near Fermi level by changing properties of material from metallic to semi-metallic in ZGNRs which can be explained as a consequence of the edge polarization effects. At all doping positions, N-doped ZGNRs are n-type while B-doped ZGNRs are p-type semiconductors. These substitutionally B- and N-doped impurities act as scattering centers for transport in GNRs. Due to unusual properties of these nanomaterials, they can be used in carbon-based nanoelectronics devices.

Chauhan, Satyendra Singh; Srivastava, Pankaj; Shrivastava, Ashwani Kumar

2014-04-01

182

Electronic and transport properties of boron and nitrogen doped graphene nanoribbons: an ab initio approach  

NASA Astrophysics Data System (ADS)

Graphene nanoribbons (GNRs) are expected to display extraordinary properties in the form of nanostructures. The effect of boron and nitrogen substitutional doping at four successive positions on electronic and transport properties of zigzag graphene nanoribbons (ZGNRs) is studied using spin-unpolarized density functional theory. It has been observed that the electronic structures of the doped ZGNRs are different from those of pristine ZGNRs. We have also calculated the transformation energy in the form of total energy. The substitutional boron atom at the nanoribbons edges suppresses the energy band near Fermi level by changing properties of material from metallic to semi-metallic in ZGNRs which can be explained as a consequence of the edge polarization effects. At all doping positions, N-doped ZGNRs are n-type while B-doped ZGNRs are p-type semiconductors. These substitutionally B- and N-doped impurities act as scattering centers for transport in GNRs. Due to unusual properties of these nanomaterials, they can be used in carbon-based nanoelectronics devices.

Chauhan, Satyendra Singh; Srivastava, Pankaj; Shrivastava, Ashwani Kumar

2013-04-01

183

Pt-polyaniline nanocomposite on boron-doped diamond electrode for amperometic biosensor with low detection limit  

Microsoft Academic Search

Boron-doped diamond electrodes covered with a nanostructured Pt nanoparticle-polyaniline composite have been fabricated and\\u000a employed as sensitive amperometric sensors with low detection limit. A highly conductive boron-doped diamond thin film (BDD)\\u000a was prepared by chemical vapor deposition, and its morphology was characterized by scanning electron microscopy and transmission\\u000a electron microscopy. The nanostructured composite layer was grown on the BDD electrode

Min-Jung Song; Jong Hoon Kim; Seung Koo Lee; Jae-Hyun Lee; Dae Soon Lim; Sung Woo Hwang; Dongmok Whang

2010-01-01

184

A first-principles study of calcium-decorated, boron-doped graphene for high capacity hydrogen storage  

Microsoft Academic Search

Hydrogen adsorption and storage on calcium-decorated, boron-doped graphene was explored using density functional theory simulations based on local density approximation and generalized gradient approximation methods. The clustering problem for calcium-decorated graphene was investigated and it was shown that individual calcium atoms are not stable on pure graphene, and formation of aggregates is favorable. Substitutional boron doping can eliminate the clustering

Elham Beheshti; Alireza Nojeh; Peyman Servati

2011-01-01

185

Field emission and Raman spectroscopy studies of atomic hydrogen etching on boron and nitrogen doped DLC films  

Microsoft Academic Search

This research studies diamond-like carbon (DLC) films doped with both boron and nitrogen prepared by microwave plasma enhanced chemical vapor deposition (MPECVD). The as-prepared samples with various doping of boron and nitrogen species were characterized using a Raman spectroscopic technique, and the electron field emission of the films was measured. The electron field emission properties of the as-deposited samples at

Y.-H. Wu; C.-M. Hsu; C.-T. Chia; I.-N. Lin; C.-L. Cheng

2002-01-01

186

Formation of graphitic structures in cobalt- and nickel-doped carbon aerogels.  

PubMed

We have prepared carbon aerogels (CAs) doped with cobalt or nickel through sol-gel polymerization of formaldehyde with the potassium salt of 2,4-dihydroxybenzoic acid, followed by ion exchange with M(NO3)2 (where M = Co2+ or Ni2+), supercritical drying with liquid CO2, and carbonization at temperatures between 400 and 1050 degrees C under a N2 atmosphere. The nanostructures of these metal-doped carbon aerogels were characterized by elemental analysis, nitrogen adsorption, high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Metallic nickel and cobalt nanoparticles are generated during the carbonization process at about 400 and 450 degrees C, respectively, forming nanoparticles that are approximately 4 nm in diameter. The sizes and size dispersion of the metal particles increase with increasing carbonization temperatures for both materials. The carbon frameworks of the Ni- and Co-doped aerogels carbonized below 600 degrees C mainly consist of interconnected carbon particles with a size of 15-30 nm. When the samples are pyrolyzed at 1050 degrees C, the growth of graphitic nanoribbons with different curvatures is observed in the Ni- and Co-doped carbon aerogel materials. The distance of graphite layers in the nanoribbons is approximately 0.38 nm. These metal-doped CAs retain the overall open cell structure of metal-free CAs, exhibiting high surface areas and pore diameters in the micro- and mesoporic region. PMID:15779927

Fu, Ruowen; Baumann, Theodore F; Cronin, Steve; Dresselhaus, Gene; Dresselhaus, Mildred S; Satcher, Joe H

2005-03-29

187

Magnetism of Co doped graphitic ZnO layers adsorbed on Si and Ag surfaces  

NASA Astrophysics Data System (ADS)

The effect of the substrate on Co doped graphitic ZnO layers adsorbed on metallic and semiconductor surfaces are investigated. The first principles results reveal that the magnetic interactions are strongly affected by the substrate. While graphitic layers of ZnO:Co on the well controlled metallic Ag(111) surface present weak ferromagnetic stability, on the semiconductor Si(111) surface they are strongly ferromagnetic coupled. The presence of metallic states in ZnO:Co adsorbed on Ag(111) surface favors a superexchange mechanism, weakening the ferromagnetic interaction. On the other hand, the magnetism of few layers of ZnO:Co on Si(111) surface is governed by a direct exchange mechanism, favoring a ferromagnetic coupling. This confined II-VI system doped with transition metal on a semiconductor surface presents higher magnetic stability than III-V nanostructures, and it is desired for nanostructured oxide/semiconductor room temperature ferromagnetism, using silicon technology.

Fernandes, Marcelo; Schmidt, Tome M.

2013-09-01

188

Effects of hole doping by neutron irradiation of magnetic field induced electronic phase transitions in graphite  

SciTech Connect

We have investigated effects of hole doping by fast-neutron irradiation on the magnetic-field induced phase transitions in graphite using specimens irradiated with fast neutrons. Resistance measurements have been done in magnetic fields of up to above 50 T and at temperatures down to about 1.5 K. The neutron irradiation creates lattice defects acting as acceptors, affecting the imbalance of the electron and hole densities and the Fermi level. We have found that the reentrant field from the field induced state back to the normal state shifts towards a lower field with hole doping, suggestive of the participation of electron subbands in the magnetic-field induced state.

Singleton, John [Los Alamos National Laboratory; Yaguchi, Hiroshi [TOKYO UNIV

2008-01-01

189

Boron-doped molybdenum silicides for structural applications  

Microsoft Academic Search

The addition of as little as 1 wt.% (=3 at.%) boron improved the oxidation resistance of Mo5Si3 by as much as five orders of magnitude over a temperature range of 800–1500°C. The mechanism of oxidation protection is the formation of a borosilicate glass scale that flows to form a passivating layer over the base intermetallic. The compositional homogeneity range for

Mufit Akinc; Mitchell K. Meyer; Matthew J. Kramer; Andrew J. Thom; Jesse J. Huebsch; Bruce Cook

1999-01-01

190

Optoelectronic studies of boron-doped and gamma-irradiated diamond thin films  

NASA Astrophysics Data System (ADS)

Elucidation of microscopic properties of a synthetic diamond, such as formation and evolution of bulk and surface defects, chemistry of dopants, etc. is necessary for a reliable quality control and reproducibility in applications. Employing surface photovoltage (SPV) and photoluminescence (PL) spectroscopic probes we studied diamond thin films grown on silicon by microwave plasma-assisted chemical vapor deposition with different levels of boron doping in conjunction with gamma irradiation. SPV measurements showed that while the increase of boron concentration leads to a semiconductor-metal transition, subsequent intense gamma irradiation reverts back the quasi-metallic samples to semiconducting state via compensating electrical activity of boron by hydrogen. One of the most pronounced common transitions in the SPV spectra was observed at ˜3.1 eV, also present in most of the PL spectra. We argue that this is a signature of the sp^2-C clusters/layers in the vicinity of grain boundaries.

Chapagain, Puskar; Nemashkalo, Anastasiia; Peters, Raul; Farmer, John; Gupta, Sanju; Strzhemechny, Yuri M.

2011-10-01

191

Synthesis, Structure and Properties of Boron and Nitrogen Doped Graphene  

Microsoft Academic Search

Two-dimensional graphene exhibits many fascinating properties such as ballistic electronic conduction and quantum Hall effect at room temperature.1-4 Graphene doped electrochemically or through charge-transfer with electron-donor and -acceptor molecules,5-7 shows marked changes in electronic structure, with characteristic signatures in the Raman spectra.5-10 Substitutional doping, universally used in tuning properties of semiconductors, could be a powerful tool to control the electronic

L. S. Panchakarla; K. S. Subrahmanyam; S. K. Saha; Achutharao Govindaraj; H. R. Krishnamurthy; U. V. Waghmare; C. N. R. Rao

2009-01-01

192

Effect of boron doping on optical properties of sol-gel based nanostructured zinc oxide films on glass  

SciTech Connect

Graphical abstract: Room temperature fine structured UV-vis PL emissions (a) as phonon replicas in 1 at.% boron doped film originated from LO phonon evidenced from Near Grazing Incidence Angle (NGIA) IR spectral study (b). Highlights: Black-Right-Pointing-Pointer Sol-gel based boron doped nanostructured ZnO thin films deposited on pure silica glass using crystalline boric acid as boron source. Black-Right-Pointing-Pointer Observed first time, room temperature fine structured PL emissions in 1 at.% doped film as phonon replicas originated from LO phonon (both IR and Raman active). Black-Right-Pointing-Pointer Boron doping controls the LO phonon energy in addition to visible reflection, band gap and grain size. Black-Right-Pointing-Pointer The films possessed mixed crystal phases with hexagonal as major phase. -- Abstract: Boron doped zinc oxide thin films ({approx}80 nm) were deposited onto pure silica glass by sol-gel dip coating technique from the precursor sol/solution of 4.0 wt.% equivalent oxide content. The boron concentration was varied from 0 to 2 at.% w.r.t. Zn using crystalline boric acid. The nanostructured feature of the films was visualized by FESEM images and the largest cluster size of ZnO was found in 1 at.% boron doped film (B1ZO). The presence of mixed crystal phases with hexagonal as major phase was identified from XRD reflections of the films. Particle size, optical band gap, visible specular reflection, room temperature photoluminescence (PL) emissions (3.24-2.28 eV), infra-red (IR) and Raman active longitudinal optical (LO) phonon vibration were found to be dependent on dopant concentration. For the first time, we report the room temperature fine structured PL emissions as phonon replicas originated from the LO phonon (both IR and Raman active) in 1 at.% boron doped zinc oxide film.

Jana, Sunirmal, E-mail: sjana@cgcri.res.in [Sol-Gel Division, CSIR-Central Glass and Ceramic Research Institute, (Council of Scientific and Industrial Research, CSIR, India), 196 Raja S. C. Mullick Road, Kolkata 700032 (India)] [Sol-Gel Division, CSIR-Central Glass and Ceramic Research Institute, (Council of Scientific and Industrial Research, CSIR, India), 196 Raja S. C. Mullick Road, Kolkata 700032 (India); Vuk, Angela Surca [National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia)] [National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); Mallick, Aparajita [Sol-Gel Division, CSIR-Central Glass and Ceramic Research Institute, (Council of Scientific and Industrial Research, CSIR, India), 196 Raja S. C. Mullick Road, Kolkata 700032 (India)] [Sol-Gel Division, CSIR-Central Glass and Ceramic Research Institute, (Council of Scientific and Industrial Research, CSIR, India), 196 Raja S. C. Mullick Road, Kolkata 700032 (India); Orel, Boris [National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia)] [National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); Biswas, Prasanta Kumar [Sol-Gel Division, CSIR-Central Glass and Ceramic Research Institute, (Council of Scientific and Industrial Research, CSIR, India), 196 Raja S. C. Mullick Road, Kolkata 700032 (India)] [Sol-Gel Division, CSIR-Central Glass and Ceramic Research Institute, (Council of Scientific and Industrial Research, CSIR, India), 196 Raja S. C. Mullick Road, Kolkata 700032 (India)

2011-12-15

193

Room temperature photoluminescence property of boron-doped sol-gel silica  

SciTech Connect

Room temperature photoluminescence (PL) of boron-doped silica synthesized by a combined sol-gel and heating process has been investigated. The broad PL band has been resolved into three components centered at 3.7, 3.35 and 2.7 eV, which are assigned to non-bridging oxygen hole centers (NBOHC), carbon-related impurity, and two-fold coordinated silicon atoms, respectively. The intensities of the 3.35 and 2.7 eV bands decrease with the heating temperature increasing, due to oxidation of the corresponding luminescent centers. The effect of boron doping on the formation of intrinsic defects in silica is discussed.

He Haiping; Wang Yuxia; Zou Youming

2004-05-05

194

Electronic properties of boron and nitrogen doped graphene nanoribbons and its application for graphene electronics  

NASA Astrophysics Data System (ADS)

On the basis of density functional theory calculations, we have systematically investigated the electronic properties of armchair-edge graphene nanoribbons (GNRs) doped with boron (B) and nitrogen (N) atoms. B (N) atoms could effectively introduce holes (electrons) to GNRs and the system exhibits p- ( n-) type semiconducting behavior after B (N) doping. According to the electronic structure calculations, Z-shape GNR-based field effect transistors (FETs) is constructed by selective doping with B or N atoms. Using first-principles quantum transport calculations, we demonstrate that the B-doped p-type GNR-FETs can exhibit high levels of performance, with high ON/OFF ratios and low subthreshold swing. Furthermore, the performance parameters of GNR-FETs could be controlled by the p-type semiconducting channel length.

Huang, Bing

2011-01-01

195

Functionalization of Boron- and Nitrogen-Doped Graphene and Carbon Nanotubes: An Ab Initio Study  

NASA Astrophysics Data System (ADS)

We study the mechanism of covalent functionalization of boron (B) and nitrogen (N) doped graphene and carbon nanotubes by carboxyl (COOH) groups. Our calculations are carried out using density functional theory combined with the generalized gradient approximation for the exchange-correlation functional. The binding energies and equilibrium geometries of carboxylated B/N-doped graphene sheets and carbon nanotubes are examined in cases of graphene and carbon nanotubes containing no defects, containing Stone-Wales defects, and containing vacancies. Our calculations show that B-doping increases and N-doping decreases the binding energy of COOH groups to defect-free and defective graphene and carbon nanotubes. This result is consistent with previous observations that carbon nanotubes and graphene act as electron acceptors with respect to COOH groups.

Al-Aqtash, Nabil; Vasiliev, Igor

2010-03-01

196

Effect of Ge doping on the kinetics of iron-boron pair association and dissociation in photovoltaic silicon  

NASA Astrophysics Data System (ADS)

We have investigated the kinetics behaviors of iron-boron pair generation in photovoltaic Czochralski silicon with germanium doping in this paper. It is found that the activation energies of iron-boron pair association and dissociation in germanium-doped silicon are 0.67 and 1.26 eV, respectively, both larger than those in conventional CZ silicon. The pre-exponential factors are also increased by one order of magnitude. Experimental results and theoretical calculations both suggest that germanium can not only improve the diffusion barrier of iron, but also increase the capture radius of boron for iron.

Zhu, Xiaodong; Yu, Xuegong; Li, Xiaoqiang; Wang, Peng; Yang, Deren

2012-06-01

197

Can boron and nitrogen co-doping improve oxygen reduction reaction activity of carbon nanotubes?  

PubMed

Two kinds of boron and nitrogen co-doped carbon nanotubes (CNTs) dominated by bonded or separated B and N are intentionally prepared, which present distinct oxygen reduction reaction (ORR) performances. The experimental and theoretical results indicate that the bonded case cannot, while the separated one can, turn the inert CNTs into ORR electrocatalysts. This progress demonstrates the crucial role of the doping microstructure on ORR performance, which is of significance in exploring the advanced C-based metal-free electrocatalysts. PMID:23317479

Zhao, Yu; Yang, Lijun; Chen, Sheng; Wang, Xizhang; Ma, Yanwen; Wu, Qiang; Jiang, Yufei; Qian, Weijin; Hu, Zheng

2013-01-30

198

Boron doped diamond\\/titanium composite electrodes for electrochemical gas generation from aqueous electrolytes  

Microsoft Academic Search

Titanium substrates were coated by 2–5?m thick boron doped diamond layers through the HFCVD-process from an activated H2\\/CH4 gas phase. The doping level was 50–230 atomppm B. The surface was saturated with ?CH2 groups. A TiC interphase was formed in situ. Stationary current–voltage curves up to j±=0.1Acm?2 were measured in three aqueous electrolytes, 1M H2SO4, 1M NaOH and 3M NaCl.

F. Beck; H. Krohn; W. Kaiser; M. Fryda; C. P. Klages; L. Schäfer

1998-01-01

199

Type conversion of boron-doped silicon wafers by 3MeV proton irradiation  

Microsoft Academic Search

Proton irradiation was conducted on Czochralski (Cz) and floating zone (Fz) boron-doped p-type Si wafers at room temperature with the doses ranging from 1×1013 cm-2 to 2×10 15 cm-2. A p-n junction formed in the Cz wafers when the dose reached a value between 1.0×1013 cm-2 and 3×1013 cm-2 while a p-n-p structure formed in the Fz wafers. The formation

Min-Doo Chun; Donghwan Kim; Jaebum Choo; Joo-Youl Huh

2000-01-01

200

Annealing of divacancy-related infrared absorption bands in boron-doped silicon  

Microsoft Academic Search

This work is devoted to an “old” defect and its annealing characteristics, namely the divacancy centre in silicon. Infrared spectroscopy is applied to study the annealing kinetics of divacancy-related absorption peaks in electron-irradiated Czochralski-grown samples doped with boron. In all specimens the kinetics show an exponential decay (first-order process) and a model taking into account both diffusion and dissociation as

B. G. Svensson; K. Johnsson; D. X. Xu; J. H. Svensson; J. L. Lindström

1989-01-01

201

Electrochemical oxidation of sulfide ion at a boron-doped diamond anode  

Microsoft Academic Search

The goal of the present research was the direct conversion of sulfide, an important contaminant in geothermal brines, to sulfate,\\u000a whose discharge limits are much less stringent than those for sulfide. By the use of a novel anode material boron-doped diamond\\u000a (BDD), we achieved near-quantitative electrochemical conversion of sulfide ions to sulfate with current efficiency of 90%.\\u000a Kinetically, the reaction

Katie Waterston; Dorin Bejan; Nigel J. Bunce

2007-01-01

202

Electro-combustion of polyacrylates with boron-doped diamond anodes  

Microsoft Academic Search

The electro-combustion of water soluble polymeric contaminants like polyacrylates (PA) in aqueous acid solution using a boron-doped diamond (BDD) anode has been investigated by bulk electrolysis in 1 mol dm?3 HClO4 under galvanostatic conditions in a wide range of PA concentrations and current densities. In all cases complete electro-combustion of PA has been achieved and this is the first successful

R Bellagamba; P. A Michaud; Ch Comninellis; N Vatistas

2002-01-01

203

Boron-doped diamond anodic treatment of olive mill wastewaters: Statistical analysis, kinetic modeling and biodegradability  

Microsoft Academic Search

The electrochemical treatment of olive mill wastewaters (OMW) over boron-doped diamond (BDD) electrodes was investigated. A factorial design methodology was implemented to evaluate the statistically important operating parameters, amongst initial COD load (1000–5000mg\\/L), treatment time (1–4h), current intensity (10–20A), initial pH (4–6) and the use of 500mg\\/L H2O2 as an additional oxidant, on treatment efficiency; the latter was assessed in

Efthalia Chatzisymeon; Nikolaos P. Xekoukoulotakis; Evan Diamadopoulos; Alexandros Katsaounis; Dionissios Mantzavinos

2009-01-01

204

The electrooxidation of sulfur-containing compounds at boron-doped diamond electrode  

Microsoft Academic Search

The electrooxidation of homocysteine, glutathione (GSH), 2-mercapto ethanesulfonic acid and cephalexin at boron-doped diamond (BDD) electrodes and glassy carbon (GC) electrodes was investigated by cyclic voltammetry. The oxidation of these sulfur-containing compounds exhibited well-defined irreversible responses. This preliminary study has shown that BDD has better sensitivity than GC. Concentration dependence has been studied and indicated the promise of using BDD

O. Chailapakul; P. Aksharanandana; T. Frelink; Y. Einaga; A. Fujishima

2001-01-01

205

Boron doped diamond ultramicroelectrodes: a generic platform for sensing single nanoparticle electrocatalytic collisions.  

PubMed

Boron doped diamond (BDD) disk ultramicroelectrodes have been used to sense single nanoparticle (NP) electrocatalytic collision events. BDD serves as an excellent support electrode due to its electrocatalytic inactivity and low background currents and thus can be used to detect the electroactivity of a wide range of colliding NPs, with high sensitivity. In particular, single NP collisions for hydrazine oxidation at Au and Pt NPs were shown to be markedly different. PMID:23680678

Wakerley, David; Güell, Aleix G; Hutton, Laura A; Miller, Thomas S; Bard, Allen J; Macpherson, Julie V

2013-06-25

206

Electrochemical oxidation of phenolic wastes with boron-doped diamond anodes  

Microsoft Academic Search

The electrochemical oxidation of several phenolic aqueous wastes has been studied using a bench-scale plant with a single-compartment electrochemical flow cell. Boron-doped diamond materials were used as the anode. Complete mineralization of the waste was obtained in the treatment of phenols not substituted with chlorine or nitrogen. Chlorinated phenolic compounds were transformed into carbon dioxide; volatile organochlorinated compounds and nitro-substituted

P. Cañizares; J. Lobato; R. Paz; M. A. Rodrigo; C. Sáez

2005-01-01

207

Electrochemical reactivity of TiO 2 nanoparticles adsorbed onto boron-doped diamond surfaces  

Microsoft Academic Search

TiO2 (anatase) nanoparticles of ca. 6–10 nm diameter are adsorbed from acidic aqueous solution onto polycrystalline industrially polished boron-doped diamond electrode surfaces. After immobilisation at the electrode surface, TiO2 nanoparticles are imaged in vacuum by electron microscopy (FEGSEM) and when immersed in a liquid film of aqueous 12 M LiCl by in situ scanning tunnelling microscopy (STM). Mono-layer films of

Frank Marken; Avninder S. Bhambra; Duk-Hyun Kim; Roger J. Mortimer; Susan J. Stott

2004-01-01

208

Electrochemical decolourisation of dispersed indigo on boron-doped diamond anodes  

Microsoft Academic Search

In denim production the decolourisation of intensively coloured, indigo-particulate containing waste water is a factor of major environmental concern. Successful anodic decolourisation of solutions containing 0.29 mM dispersed indigo and 0.070 M Na2SO4 could be achieved on boron-doped diamond electrodes. Current densities were varied from 0.36 to 80 mA cm?2. Relative current efficiency decreases with increased current density from 43%

Thomas Bechtold; Aurora Turcanu; Wolfgang Schrott

2006-01-01

209

Oxidation of carboxylic acids at boron-doped diamond electrodes for wastewater treatment  

Microsoft Academic Search

Thin boron-doped diamond films have been prepared by HF CVD (hot filament chemical vapour deposition technique) on conductive p-Si substrate (Si\\/Diamond). The morphology of these Si\\/diamond electrodes has been investigated by SEM and Raman spectroscopy. The electrochemical behaviour of the Si\\/diamond electrodes in 1 M H2SO4 and in 1 M H2SO4 + carboxylic acids has been investigated by cyclic voltammetry.

D. Gandini; E. Mahé; P. A. Michaud; W. Haenni; A. Perret; Ch. Comninellis

2000-01-01

210

A comparison of electrochemical degradation of phenol on boron doped diamond and lead dioxide anodes  

Microsoft Academic Search

This work compares two electrode materials used to mineralize phenol contained in waste waters. Two disks covered with either\\u000a boron doped diamond (BDD) or PbO2 were used as anodes in a one compartment flow cell under the same hydrodynamic conditions. Efficiencies of galvanostatic\\u000a electrolyses are compared on the basis of measurements of Total Organic Carbon (TOC) and Chemical Oxygen Demand

Elsa Weiss; Karine Groenen-Serrano; André Savall

2008-01-01

211

Amperometric biosensor based on tyrosinase immobilized on a boron-doped diamond electrode  

Microsoft Academic Search

A novel method has been developed to immobilize tyrosinase onto the surface of boron-doped diamond (BDD) electrode. The hydrogen-terminated BDD (HBDD) surface was first functionalized by photochemically linking vinyl groups of allylamine, producing covalently linked amine-terminated active BDD (ABDD) surface. Then the tyrosinase was immobilized onto the ABDD surface by carbodiimide coupling reaction. The amperometric response was measured as a

Yan Li Zhou; Ru Hai Tian; Jin Fang Zhi

2007-01-01

212

Tyrosinase-modified boron-doped diamond electrodes for the determination of phenol derivatives  

Microsoft Academic Search

Highly boron-doped diamond (BDD) electrodes were modified covalently with tyrosinase for the determination of estrogenic phenol derivatives. BDD was anodically polarized for the introduction of hydroxyl groups onto its surface, then treated with (3-aminopropyl)triethoxysilane and finally coated with a tyrosinase film cross-linked with glutaraldehyde. The modified electrodes responded amperometrically to phenol derivatives including estrogenic derivatives, bisphenol-A and 17?-estradiol, at ?0.3

Hideo Notsu; Tetsu Tatsuma; Akira Fujishima

2002-01-01

213

Electron Transfer Kinetics on Boron-Doped Diamond Part I: Influence of Anodic Treatment  

Microsoft Academic Search

Boron-doped diamond electrodes, both as-grown and polarized anodically under different conditions, were prepared in order to study the chemical and electrochemical changes of diamond and clarify the role played by the surface-state density. Many different treatments were employed: as-grown (BDDag), mildly polarized (BDDmild), strongly polarized in perchloric acid (BDDsevererpar;, and strongly polarized in a sulphuric acid-acetic acid mixture (BDDAcOHrpar;. Charge

I. Duo; C. Levy-Clement; A. Fujishima; C. Comninellis

2004-01-01

214

Electrochemical oxidation of water on synthetic boron-doped diamond thin film anodes  

Microsoft Academic Search

Electrolysis in aqueous 1 M HClO4 and 1 M H2SO4 solutions has been carried out under galvanostatic conditions using boron-doped diamond electrodes (BDD). Analyses of the oxidation products have shown that in 1 M HClO4 the main reaction is oxygen evolution, while in H2SO4 the main reaction is the formation of H2S2O8. In both electrolytes small amounts of O3 and

P. A. Michaud; M. Panizza; L. Ouattara; T. Diaco; G. Foti; Ch. Comninellis

2003-01-01

215

Electrochemical preparation of peroxodisulfuric acid using boron doped diamond thin film electrodes  

Microsoft Academic Search

We have investigated the electrochemical oxidation of sulfuric acid on boron-doped synthetic diamond electrodes (BDD) obtained by HF CVD on p-Si. The results have shown that high current efficiency for sulfuric acid oxidation to peroxodisulfuric acid can be achieved in concentrated H2SO4 (>2 M) at moderate temperatures (8–10°C). The main side reaction is oxygen evolution. Small amounts of peroxomonosulfuric acid

K. Serrano; P. A. Michaud; C. Comninellis; A. Savall

2002-01-01

216

Cadmium detection via boron-doped diamond electrodes: surfactant inhibited stripping voltammetry  

Microsoft Academic Search

The deposition of cadmium on boron-doped diamond is investigated with square-wave anodic stripping voltammetry. The system was investigated in quiescent conditions, in the presence of an acoustic field and then in the presence of the neutral surfactant Triton® X-100. The effect of optimised insonation was to increase the sensitivity from 0.63 (under silent conditions) to 3.78?A?M?1 and to reduce the

Craig E. Banks; Michael E. Hyde; Peter Tom???k; Robert Jacobs; Richard G. Compton

2004-01-01

217

Square wave voltammetry on boron-doped diamond electrodes for analytical determinations  

Microsoft Academic Search

The use of square wave voltammetry in conjunction with a boron-doped diamond electrode for the analytical determination of pentachlorophenol is described. After optimization of the experimental conditions, that model molecule was analyzed in pure and natural waters using a Britton–Robinson buffer (pH=5.5) as the supporting electrolyte. Oxidation occurs at 0.80 V vs. Ag\\/AgCl in a two-electron process controlled by adsorption

L. Codognoto; S. A. S. Machado; L. A. Avaca

2002-01-01

218

A kinetic study of the electrochemical oxidation of maleic acid on boron doped diamond  

Microsoft Academic Search

Maleic acid (MA) is one of the main intermediates formed during mineralization, by electrooxidation, of aromatic compounds\\u000a contained in aqueous wastes. This work investigates oxidation of maleic acid with or without the presence of oxalic acid (OA)\\u000a and formic acid (FA) in aqueous solution by using boron-doped diamond (BDD) electrodes. OA and FA are the main products formed\\u000a in MA

Elsa Weiss; Karine Groenen-Serrano; André Savall; Christos Comninellis

2007-01-01

219

Anodic oxidation of 2-naphthol at boron-doped diamond electrodes  

Microsoft Academic Search

The anodic oxidation of 2-naphthol in acid media was investigated at a synthetic boron-doped diamond thin film electrode (BDD) using cyclic voltammetry and bulk electrolysis. The results have shown that in the potential region, where the supporting electrolyte is stable, reactions involving simple electron transfer, such as oxidation of 2-naphthol to naphthoxy radical and 1,4-naphthoquinone occur. Polymeric materials, which lead

M. Panizza; P. A. Michaud; G. Cerisola; Ch. Comninellis

2001-01-01

220

Improving corrosion-resistance of polysilicon using boron doping and self-induced galvanic bias  

Microsoft Academic Search

In this paper we report upon two novel methods for improving the corrosion resistance of silicon-glass micropackages in high temperature saline soak tests. By using boron doping and\\/or galvanic biasing, we have shown that the dissolution of polysilicon can be reduced from more that 1 ?m \\/day to less than 90 Å\\/day. Physical mechanisms for polysilicon corrosion are also presented.

Brian H. Stark; Mehmet R. Dokmeci; Khalil Najafi

2003-01-01

221

Electrochemical treatment of 2,4-dinitrophenol aqueous wastes using boron-doped diamond anodes  

Microsoft Academic Search

The electrochemical oxidation of 2,4-dinitrophenol (2,4-DNP) aqueous wastes has been studied using both, bulk electrolysis and voltammetric techniques. To carry out the bulk electrolysis, a bench-scale plant with a single compartment electrochemical flow cell was used. Boron-doped diamond (BDD) materials were used as the anode and stainless steel (AISI 304) as the cathode. According to the obtained results, a simple

P. Cañizares; C. Sáez; J. Lobato; M. A. Rodrigo

2004-01-01

222

An optimized experimental method for measuring thermal conductivity of thin, boron-doped diamond films  

Microsoft Academic Search

A novel experimental method has been developed and applied to measure the thermal conductivity of a thin (5.6 ?m thick) boron-doped diamond film produced by a hot filament CVD process. Thermal fields were created by Joule heating in a 3-mm-diam, free-standing diamond diaphragm; infrared imaging thermography was used to quantify these fields. Parameter estimation was applied to determine the thermal

S. A. Herr; J. V. Beck; J. J. McGrath; S. Sahli; M. Aslam

1995-01-01

223

Density Functional Theory Study of Boron and Nitrogen-Atom-Doped Graphene Chips  

Microsoft Academic Search

The structures and electronic states of boron- and nitrogen-substituted graphene chips (B-, N-, and BN-doped graphene chips) have been investigated by means of the density functional theory (DFT) method in order to shed light on the mechanism of change in the electronic properties of graphene chips caused by heteroatoms. The atomic charge of nitrogen atoms in N-graphene was a negative

Hiroto Tachikawa; Tetsuji Iyama; Kazuhisa Azumi

2011-01-01

224

Nitrogen and boron doping effects on the electrical conductivity of graphene and nanotube  

Microsoft Academic Search

The effects of nitrogen and boron doping on the density of states and the temperature dependence of the electrical conductivity of graphene plane and (10,0) single-walled carbon nanotube are studied. We apply the Green’s function technique and coherent potential approximation within the tight-binding Hamiltonian model. We find that when dopants are introduced, van-Hove singularities in the density of states are

Hamze Mousavi; Rostam Moradian

2011-01-01

225

Controlled electrochemical intercalation, exfoliation and in situ nitrogen doping of graphite in nitrate-based protic ionic liquids.  

PubMed

Few-layer nitrogen-doped graphene has been prepared via fast and controlled electrochemical exfoliation of graphite in a protic ionic liquid ethylammonium nitrate. The method presents a potentially scalable approach for preparation of metal-free, N-doped graphene for use as electrocatalysts for oxygen reduction reactions. PMID:24169792

Lu, Xunyu; Zhao, Chuan

2013-12-14

226

Forming mechanism of nitrogen doped graphene prepared by thermal solid-state reaction of graphite oxide and urea  

NASA Astrophysics Data System (ADS)

Nitrogen doped graphene was synthesized from graphite oxide and urea by thermal solid-state reaction. The samples were characterized by transmission electron microscopy, atomic force microscopy, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectra, element analysis, and electrical conductivity measurement. The results reveal that there is a gradual thermal transformation of nitrogen bonding configurations from amide form nitrogen to pyrrolic, then to pyridinic, and finally to "graphitic" nitrogen in graphene sheets with increasing annealing temperature from 200 to 700 °C. The products prepared at 600 °C and 700 °C show that the quantity of nitrogen incorporated into graphene lattice is ˜10 at.% with simultaneous reduction of graphite oxide. Oxygen-containing functional groups in graphite oxide are responsible for the doping reaction to produce nitrogen doped graphene.

Mou, Zhigang; Chen, Xiaoye; Du, Yukou; Wang, Xiaomei; Yang, Ping; Wang, Suidong

2011-12-01

227

Electrochemical properties of boron-doped ordered mesoporous carbon as electrocatalyst and Pt catalyst support.  

PubMed

The electrochemical properties of boron-doped ordered mesoporous carbon (BOMC) as an electrode material and Pt catalyst support were investigated. The BOMC was synthesized and its structure was examined by transmission electron microscopy (TEM), scanning electron microscopy, nitrogen adsorption-desorption, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). More defective sites were introduced into OMC by the doping of boron. Six electroactive compounds were employed to investigate their electrochemical responses on BOMC and OMC modified glassy carbon electrodes. The BOMC, with more defective sites, exhibited high activity toward the electroactive compounds. The property of BOMC of supporting platinum nanoparticle catalyst was examined. Pt nanoparticles were loaded onto BOMC and OMC, and this was confirmed by TEM, XPS and thermogravimetric analysis. Pt nanoparticles with an average diameter of 2.62nm were deposited on BOMC. The doping of boron into OMC facilitates the dispersion of Pt nanoparticles. Pt nanoparticles supported on BOMC (Pt-BOMC) and Pt nanoparticles supported on OMC (Pt-OMC) were electrochemically characterized. The electrocatalytic activity of Pt-BOMC toward methanol oxidation reaction was compared with that of Pt-OMC and commercial Pt-C catalyst. The results show that the electrocatalytic activity of BOMC is significantly higher than that of other used catalysts. PMID:24910045

Nsabimana, Anaclet; Bo, Xiangjie; Zhang, Yufan; Li, Mian; Han, Ce; Guo, Liping

2014-08-15

228

Boron-doped carbon-iron nanocomposites as efficient oxygen reduction electrocatalysts derived from carbon dioxide.  

PubMed

Developing cost-effective oxygen reduction reaction (ORR) catalysts is pivotal for development of fuel cells. While Fe-N-C catalysts were proposed for ORR, Fe-B-C catalysts have not been explored. This work introduces the B-doped carbon catalysts encapsulating iron cores using CO2 as a carbon source. The Fe-B-C catalysts show enhanced ORR activity and durability due to the iron core within the graphitic layers. PMID:24797546

Zhang, Junshe; Byeon, Ayeong; Lee, Jae W

2014-06-18

229

Surface damages in diamond by Ar/O{sub 2} plasma and their effect on the electrical and electrochemical characteristics of boron-doped layers  

SciTech Connect

Epitaxial single crystal and boron-doped diamond layers were exposed to reactive ion etching in Ar/O{sub 2} plasma (rf power of 25 W and self-bias of 100 V); and the electrical, structural, and electrochemical characteristics of the exposed surface were investigated. Angle-resolved x-ray photoemission spectroscopy (XPS) measurements revealed a nonuniform layer of amorphous carbon at the exposed surface with an average thickness of approximately 4 nm, as confirmed also by atomic force microscopy profiling of selectively etched areas. On highly boron-doped diamond, the plasma-induced damages resulted also in a nonconductive surface layer. This damaged and insulating surface layer remained resistant to graphite-etching chemicals and to rf oxygen plasma but it was removed completely in microwave hydrogen plasma at 700 deg. C. The surface characteristics after the H-plasma process followed by wet chemical oxidation were restored back to the initial state, as confirmed by XPS. Such ''recovery'' treatment had been applied to an all-diamond submicrometer electrode array initially patterned by an Ar/O{sub 2} plasma etching. The electrochemical characteristics of this electrode array were improved by more than two orders of magnitude, approaching theoretical limit for the given geometrical configuration.

Denisenko, A.; Pietzka, C.; Scharpf, J.; Kohn, E. [Institute of Electron Devices and Circuits, University of Ulm, 89069 Ulm (Germany); Romanyuk, A. [Institute of Physics, University of Basel, 4056 Basel (Switzerland)

2010-10-15

230

Structure and electronic properties of Mg-doped {beta}-rhombohedral boron constructed from icosahedral clusters  

SciTech Connect

High-T{sub C} superconductivity is possible upon metallic-element doping into {beta}-rhombohedral boron ({beta}-B{sub 105}), which is one of the boron icosahedral cluster solids. We attempted magnesium (Mg) doping into {beta}-B{sub 105} and discussed the possibility of metal transition and superconductivity. We achieved Mg doping into {beta}-B{sub 105} at a high Mg concentration of up to MgB{sub 11.5} (8.6 Mg/cell), i.e., electron doping sufficient for the Fermi energy (E{sub F}) to reach the conduction band over the intrinsic acceptor level (IAL) and trapping levels. However, neither metal transition nor superconductivity was observed. The changes in the structure and electronic properties are discussed on the basis of the results of x-ray powder diffraction using the Rietveld method and electrical conductivity and magnetic susceptibility measurements, respectively. We estimated the density of states near E{sub F} and discussed the electronic states of {beta}-B{sub 105}. From the result, it is suggested that a localized state exists above the IAL probably originating from the B{sub 28} cluster with structural defects.

Hyodo, H.; Araake, S.; Hosoi, S.; Kimura, K. [Department of Advanced Materials Science, The University of Tokyo, 277-8561 Chiba (Japan); Soga, K. [Department of Materials Science and Technology, Tokyo University of Science, 278-8510 Chiba (Japan); Sato, Y.; Terauchi, M. [Institute for Multidisciplinary Research for Advanced Materials, Tohoku University, 980-8577 Miyagi (Japan)

2008-01-01

231

Amperometric glucose biosensor based on boron-doped carbon nanotubes modified electrode.  

PubMed

Doped carbon nanotubes are now extremely attractive and important nanomaterials in bioanalytical applications due to their unique physicochemical properties. In this paper, the boron-doped carbon nanotubes (BCNTs) were used in amperometric biosensors. It has been found that the electrocatalytic activity of the BCNTs modified glassy carbon (GC) electrode toward the oxidation of hydrogen peroxide is much higher than that of the un-doped CNTs modified electrode due to the large amount of edge sites and oxygen-rich groups located at the defective sites induced by boron doping. Glucose oxidase (GOD) was selected as the model enzyme and immobilized on the BCNTs modified glassy carbon electrode by entrapping GOD into poly(o-aminophenol) film. The performance of the sensor was investigated by electrochemical methods. At an optimum potential of +0.60 V and pH 7.0, the biosensor exhibits good characteristics, such as high sensitivity (171.2 nA mM(-1)), low detection limit (3.6 microM), short response time (within 6s), satisfactory anti-interference ability and good stability. The apparent Michaelis-Menten constant (K(m)(app)) is 15.19 mM. The applicability to the whole blood analysis of the enzyme electrode was also evaluated. PMID:18656655

Chen, Xiaoli; Chen, Jinhua; Deng, Chunyan; Xiao, Chunhui; Yang, Yanmin; Nie, Zhou; Yao, Shouzhuo

2008-08-15

232

Metal-to-insulator transition and superconductivity in boron-doped diamond.  

PubMed

The experimental discovery of superconductivity in boron-doped diamond came as a major surprise to both the diamond and the superconducting materials communities. The main experimental results obtained since then on single-crystal diamond epilayers are reviewed and applied to calculations, and some open questions are identified. The critical doping of the metal-to-insulator transition (MIT) was found to coincide with that necessary for superconductivity to occur. Some of the critical exponents of the MIT were determined and superconducting diamond was found to follow a conventional type II behaviour in the dirty limit, with relatively high critical temperature values quite close to the doping-induced insulator-to-metal transition. This could indicate that on the metallic side both the electron-phonon coupling and the screening parameter depend on the boron concentration. In our view, doped diamond is a potential model system for the study of electronic phase transitions and a stimulating example for other semiconductors such as germanium and silicon. PMID:18024360

Bustarret, E; Achatz, P; Sacépé, B; Chapelier, C; Marcenat, C; Ortéga, L; Klein, T

2008-01-28

233

Effect of diborane on the microstructure of boron-doped silicon nanowires  

NASA Astrophysics Data System (ADS)

Boron-doped silicon (Si) nanowires, with nominal diameters of 80 nm, were grown via the vapor-liquid-solid (VLS) mechanism using gold (Au) as a catalyst and silane (SiH 4) and diborane (B 2H 6) as precursors. The microstructure of the nanowires was studied by scanning electron microscopy, transmission electron microscopy and electron energy-loss spectroscopy. At lower B 2H 6 partial pressure and thus lower doping levels (?1×10 18 cm -3), most of the boron-doped Si nanowires exhibited high crystallinity. At higher B 2H 6 partial pressure (˜2×10 19 cm -3 doping level), the majority of the wires exhibited a core-shell structure with an amorphous Si shell (20-30 nm thick) surrounding a crystalline Si core. Au nanoparticles on the outer surface of the nanowires were also observed in structures grown with high B/Si gas ratios. The structural changes are believed to result from an increase in the rate of Si thin-film deposition on the outer surface of the nanowire at high B 2H 6 partial pressure, which produces the amorphous coating and also causes an instability at the liquid/solid interface resulting in a loss of Au during nanowire growth.

Pan, Ling; Lew, Kok-Keong; Redwing, Joan M.; Dickey, Elizabeth C.

2005-04-01

234

Radiation tolerance of boron doped dendritic web silicon solar cells  

NASA Technical Reports Server (NTRS)

The potential of dendritic web silicon for giving radiation hard solar cells is compared with the float zone silicon material. Solar cells with n(+)-p-P(+) structure and approximately 15% (AMl) efficiency were subjected to 1 MeV electron irradiation. Radiation tolerance of web cell efficiency was found to be at least as good as that of the float zone silicon cell. A study of the annealing behavior of radiation-induced defects via deep level transient spectroscopy revealed that E sub v + 0.31 eV defect, attributed to boron-oxygen-vacancy complex, is responsible for the reverse annealing of the irradiated cells in the temperature range of 150 to 350 C.

Rohatgi, A.

1980-01-01

235

Boron-doped nanocrystalline diamond microelectrode arrays monitor cardiac action potentials.  

PubMed

The expansion of diamond-based electronics in the area of biological interfacing has not been as thoroughly explored as applications in electrochemical sensing. However, the biocompatibility of diamond, large safe electrochemical window, stability, and tunable electronic properties provide opportunities to develop new devices for interfacing with electrogenic cells. Here, the fabrication of microelectrode arrays (MEAs) with boron-doped nanocrystalline diamond (BNCD) electrodes and their interfacing with cardiomyocyte-like HL-1 cells to detect cardiac action potentials are presented. A nonreductive means of structuring doped and undoped diamond on the same substrate is shown. The resulting BNCD electrodes show high stability under mechanical stress generated by the cells. It is shown that by fabricating the entire surface of the MEA with NCD, in patterns of conductive doped, and isolating undoped regions, signal detection may be improved up to four-fold over BNCD electrodes passivated with traditional isolators. PMID:23949946

Maybeck, Vanessa; Edgington, Robert; Bongrain, Alexandre; Welch, Joseph O; Scorsone, Emanuel; Bergonzo, Philippe; Jackman, Richard B; Offenhäusser, Andreas

2014-02-01

236

Electrical transport properties of Si-doped hexagonal boron nitride epilayers  

SciTech Connect

The suitability of Si as an n-type dopant in hexagonal boron nitride (hBN) wide bandgap semiconductor has been investigated. Si doped hBN epilayers were grown via in-situ Si doping by metal organic chemical vapor deposition technique. Hall effect measurements revealed that Si doped hBN epilayers exhibit n-type conduction at high temperatures (T > 800 K) with an in-plane resistivity of ?12 ?·cm, electron mobility of ? ? 48 cm{sup 2}/V·s and concentration of n ? 1 × 10{sup 16} cm{sup ?3}. Temperature dependent resistivity results yielded a Si energy level in hBN of about 1.2 eV, which is consistent with a previously calculated value for Si substitutionally incorporated into the B sites in hBN. The results therefore indicate that Si is not a suitable dopant for hBN for room temperature device applications.

Majety, S.; Doan, T. C.; Li, J.; Lin, J. Y.; Jiang, H. X., E-mail: hx.jiang@ttu.edu [Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, TX 79409 (United States)

2013-12-15

237

Cobalt monoxide-doped porous graphitic carbon microspheres for supercapacitor application.  

PubMed

A novel design and facile synthesis process for carbon based hybrid materials, i.e., cobalt monoxide (CoO)-doped graphitic porous carbon microspheres (Co-GPCMs), have been developed. With the synthesis strategy, the mixture of cobalt gluconate, ?-cyclodextrin and poly (ethylene oxide)???-poly (propylene oxide)??-poly (ethylene oxide)??? is treated hydrothermally, followed by pyrolysis in argon. The resultant Co-GPCMs exhibits a porous carbon matrix with localized graphitic structure while CoO nanodots are embedded in the carbon frame. Thus, the Co-GPCMs effectively combine the electric double-layer capacitance and pseudo-capacitance when used as the electrode in supercapacitor, which lead to a higher operation voltage (1.6?V) and give rise to a significantly higher energy density. This study provides a new research strategy for electrode materials in high energy density supercapacitors. PMID:24113335

Yang, Zheng-Chun; Tang, Chun-Hua; Zhang, Yu; Gong, Hao; Li, Xu; Wang, John

2013-01-01

238

Analytical and experimental studies of graphite-epoxy and boron-epoxy angle ply laminates in shear  

NASA Technical Reports Server (NTRS)

The results of a comparison study between a test program on the inelastic response under inplane shear over a wide range of graphite-epoxy and boron-epoxy angle-ply laminates are reported. This investigation was aimed at evaluating the applicability and adequacy of these analyses to predict satisfactorily the responses of angle-ply laminates. It was observed that these analytical tools are inadequate for this purpose as they fail to predict with sufficient confidence the shape of response and in particular the strength values associated with a given laminate configuration. Consequently, they do not provide the sought-after information about failure mechanisms which trigger failure of a particular designed laminate.

Weller, T.

1977-01-01

239

Nonlinear optical properties of boron doped single-walled carbon nanotubes.  

PubMed

Single-walled carbon nanotubes (SWCNTs) exhibit excellent nonlinear optical (NLO) properties due to the delocalized ? electron states present along their tube axis. Using the open aperture Z-scan method in tandem with X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, we demonstrate the simultaneous tailoring of both electronic and NLO properties of SWCNTs, from ultrafast (femtosecond) to relatively slow (nanosecond) timescales, by doping with a single substituent, viz., boron. SWCNTs were doped via a wet chemical method using B2O3, and the boron content and bonding configurations were identified using XPS. While in the ns excitation regime, the nonlinear absorption was found to increase with increasing boron concentration in the SWCNTs (due to the increasing disorder and enhanced metallicity of the SWCNTs), the saturation intensity in the fs excitation regime decreased. We attribute this counter-intuitive behavior to excited state absorption on ns timescales, and saturable absorption combined with weak two-photon transitions on fs timescales between van Hove singularities. PMID:23817830

Anand, Benoy; Podila, Ramakrishna; Ayala, Paola; Oliveira, Luciana; Philip, Reji; Sai, S Siva Sankara; Zakhidov, Anvar A; Rao, Apparao M

2013-08-21

240

Nonlinear optical properties of boron doped single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

Single-walled carbon nanotubes (SWCNTs) exhibit excellent nonlinear optical (NLO) properties due to the delocalized ? electron states present along their tube axis. Using the open aperture Z-scan method in tandem with X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, we demonstrate the simultaneous tailoring of both electronic and NLO properties of SWCNTs, from ultrafast (femtosecond) to relatively slow (nanosecond) timescales, by doping with a single substituent, viz., boron. SWCNTs were doped via a wet chemical method using B2O3, and the boron content and bonding configurations were identified using XPS. While in the ns excitation regime, the nonlinear absorption was found to increase with increasing boron concentration in the SWCNTs (due to the increasing disorder and enhanced metallicity of the SWCNTs), the saturation intensity in the fs excitation regime decreased. We attribute this counter-intuitive behavior to excited state absorption on ns timescales, and saturable absorption combined with weak two-photon transitions on fs timescales between van Hove singularities.

Anand, Benoy; Podila, Ramakrishna; Ayala, Paola; Oliveira, Luciana; Philip, Reji; Sankara Sai, S. Siva; Zakhidov, Anvar A.; Rao, Apparao M.

2013-07-01

241

Adsorption of hydrogen molecules on the platinum-doped boron nitride nanotubes  

NASA Astrophysics Data System (ADS)

Adsorption of hydrogen molecules on platinum-doped single-walled zigzag (8,0) boron nitride (BN) nanotube is investigated using the density-functional theory. The Pt atom tends to occupy the axial bridge site of the BN tube with the highest binding energy of -0.91 eV. Upon Pt doping, several occupied and unoccupied impurity states are induced, which reduces the band gap of the pristine BN nanotube. Upon hydrogen adsorption on Pt-doped BN nanotube, the first hydrogen molecule can be chemically adsorbed on the Pt-doped BN nanotube without crossing any energy barrier, whereas the second hydrogen molecule has to overcome a small energy barrier of 0.019 eV. At least up to two hydrogen molecules can be chemically adsorbed on a single Pt atom supported by the BN nanotube, with the average adsorption energy of -0.365 eV. Upon hydrogen adsorption on a Pt-dimer-doped BN nanotube, the formation of the Pt dimer not only weakens the interaction between the Pt cluster and the BN nanotube but also reduces the average adsorption energy of hydrogen molecules. These calculation results can be useful in the assessment of metal-doped BN nanotubes as potential hydrogen storage media.

Wu, Xiaojun; Yang, J. L.; Zeng, X. C.

2006-07-01

242

Adsorption of hydrogen molecules on the platinum-doped boron nitride nanotubes.  

PubMed

Adsorption of hydrogen molecules on platinum-doped single-walled zigzag (8,0) boron nitride (BN) nanotube is investigated using the density-functional theory. The Pt atom tends to occupy the axial bridge site of the BN tube with the highest binding energy of -0.91 eV. Upon Pt doping, several occupied and unoccupied impurity states are induced, which reduces the band gap of the pristine BN nanotube. Upon hydrogen adsorption on Pt-doped BN nanotube, the first hydrogen molecule can be chemically adsorbed on the Pt-doped BN nanotube without crossing any energy barrier, whereas the second hydrogen molecule has to overcome a small energy barrier of 0.019 eV. At least up to two hydrogen molecules can be chemically adsorbed on a single Pt atom supported by the BN nanotube, with the average adsorption energy of -0.365 eV. Upon hydrogen adsorption on a Pt-dimer-doped BN nanotube, the formation of the Pt dimer not only weakens the interaction between the Pt cluster and the BN nanotube but also reduces the average adsorption energy of hydrogen molecules. These calculation results can be useful in the assessment of metal-doped BN nanotubes as potential hydrogen storage media. PMID:16942171

Wu, Xiaojun; Yang, J L; Zeng, X C

2006-07-28

243

Study on depth profiles of hydrogen in boron-doped diamond films by elastic recoil detection analysis  

SciTech Connect

Depth profiles of hydrogen in a set of boron-doped diamond films were studied by a convolution method to simulate the recoil proton spectra induced by {sup 4}He ions of 3 MeV. Results show that the hydrogen depth profiles in these varying-level boron-doped diamond films exhibit a similar three-layer structure: the surface absorption layer, the diffusion region, and the uniform hydrogen-containing matrix. Hydrogen concentrations at all the layers, especially in the surface layer, are found to increase significantly with the boron-doping concentration, implying that more dangling-bonds and/or CH-bonds were introduced by the boron-doping process. While the increased dangling-bonds and/or CH-bonds degrade the microstructure of the diamond films as observed by Raman Shift, the boron-doping significantly reduces the specific resistance and makes semiconducting diamond films possible. Hydrogen mobility (or hydrogen loss) in these films as a result of the {sup 4}He beam irradiation was also observed and discussed.

Changgeng, Liao; Shengsheng, Yang; Ximeng, Chen [Department of Modern Physics, Lanzhou University, Lanzhou, Gansu Province, 730001 (China); Yongqiang, Wang [Center for Interfacial Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

1999-06-10

244

Photodegradation of aniline by goethite doped with boron under ultraviolet and visible light irradiation  

SciTech Connect

Highlights: {yields} Goethite modified by boron was prepared by sol-gel method in presence of boron acid at the low temperature. {yields} B-goethite has slight red shift in the band gap transition beside their stronger light absorption compared with pristine goethite. {yields} The results showed that semiconductor photocatalytic reaction mechanism should exist in the process of aniline degradation with goethite and B-goethite as photocatalyst. -- Abstract: In the present study, goethite and goethite doped with boron (B-goethite) were employed to detect the presence or absence of semiconductor photocatalytic reaction mechanism in the reaction systems. B-goethite was prepared by sol-gel method in presence of boron acid in order to improve its photocatalystic efficiency under the ultraviolet and visible light irradiation. The optical properties of goethite and B-goethite were characterized by ultraviolet and visible absorption spectra and the result indicated that B-goethite has slight red shift in the band gap transition beside their stronger light absorption compared with pristine goethite. Degradation of aniline was investigated in presence of goethite and B-goethite in aqueous solution. It was found that the B-goethite photocatalyst exhibited enhanced ultraviolet and visible light photocatalytic activity in degradation of aniline compared with the pristine goethite. The photocatalytic degradation mechanism of B-goethite was discussed.

Liu, Guanglong [Laboratory of Plant Nutrition and Ecological Environment Research, Centre for Microelement Research of Huazhong Agricultural University, Key Laboratory of Subtropical Agriculture and Environment, Ministry of Agriculture, Wuhan 430070 (China)] [Laboratory of Plant Nutrition and Ecological Environment Research, Centre for Microelement Research of Huazhong Agricultural University, Key Laboratory of Subtropical Agriculture and Environment, Ministry of Agriculture, Wuhan 430070 (China); Liao, Shuijiao [Laboratory of Plant Nutrition and Ecological Environment Research, Centre for Microelement Research of Huazhong Agricultural University, Key Laboratory of Subtropical Agriculture and Environment, Ministry of Agriculture, Wuhan 430070 (China) [Laboratory of Plant Nutrition and Ecological Environment Research, Centre for Microelement Research of Huazhong Agricultural University, Key Laboratory of Subtropical Agriculture and Environment, Ministry of Agriculture, Wuhan 430070 (China); College of Basic Sciences of Huazhong Agricultural University, Wuhan 430070 (China); Zhu, Duanwei, E-mail: zhudw@mail.hzau.edu.cn [Laboratory of Plant Nutrition and Ecological Environment Research, Centre for Microelement Research of Huazhong Agricultural University, Key Laboratory of Subtropical Agriculture and Environment, Ministry of Agriculture, Wuhan 430070 (China)] [Laboratory of Plant Nutrition and Ecological Environment Research, Centre for Microelement Research of Huazhong Agricultural University, Key Laboratory of Subtropical Agriculture and Environment, Ministry of Agriculture, Wuhan 430070 (China); Liu, Linghua; Cheng, Dongsheng; Zhou, Huaidong [China Institute of Water Resources and Hydropower Research, Beijing 100038 (China)] [China Institute of Water Resources and Hydropower Research, Beijing 100038 (China)

2011-08-15

245

Diamond ultraviolet photovoltaic cell obtained by lithium and boron doping  

SciTech Connect

Polycrystalline high quality freestanding 300-{mu}m-thick diamond films were doped by diffusion of B and Li under electric bias in order to fabricate vertical p-n junctions. Circular contacts were obtained by high dose ion implantation of B and Li. The I{endash}V characteristics were rectifying. When illuminated by deuterium lamp, an open circuit voltage was 2.6 eV. The shape of the I{endash}V characteristic under illumination points to the existence of shunt and series resistances. The obtained structure is most probably a p-n junction with bad contacts. {copyright} {ital 1997 American Institute of Physics.}

Popovici, G. [Nuclear Engineering Department, University of Missouri-Columbia, Columbia, Missouri 65211 (United States)] [Nuclear Engineering Department, University of Missouri-Columbia, Columbia, Missouri 65211 (United States); Melnikov, A.; Varichenko, V.V. [Physics Department, Minsk State University, Minsk (Belarus)] [Physics Department, Minsk State University, Minsk (Belarus); Sung, T.; Prelas, M.A. [Nuclear Engineering Department, University of Missouri-Columbia, Columbia, Missouri 65211 (United States)] [Nuclear Engineering Department, University of Missouri-Columbia, Columbia, Missouri 65211 (United States); Wilson, R.G. [Hughes Research Laboratories, Malibu, California 90265 (United States)] [Hughes Research Laboratories, Malibu, California 90265 (United States); Loyalka, S.K. [Particulate Systems Research Center, University of Missouri-Columbia, Columbia, Missouri 65211 (United States)] [Particulate Systems Research Center, University of Missouri-Columbia, Columbia, Missouri 65211 (United States)

1997-03-01

246

Boron  

MedlinePLUS

... and muscle coordination. Women sometimes use capsules containing boric acid, the most common form of boron, inside the vagina to treat yeast infections. People also apply boric acid to the skin as an astringent or to ...

247

Electrical properties and far infrared optical conductivity of boron-doped single-walled carbon nanotube films.  

PubMed

Here we report a new approach for producing clean and homogeneous boron-doped single-walled carbon nanotubes. This approach combines the homogeneous dispersion of B(n)O(m)(+) ionic molecules over the nanotube surfaces in a liquid solution, with a high temperature chemical reaction that incorporates the boron atoms into the sp(2) carbon network of the nanotube wall. A comparative study of sheet resistance versus optical transmission in nanotube network films with and without boron-doping is also presented. Although electron energy loss spectroscopy revealed very low B-doping levels (<1 at.%), the dc conductivity of doped samples was raised by a factor of 3.4. Changes in the free carrier contribution to the optical conductivity of single-walled carbon nanotube (SWCNT) films induced by boron-doping was also studied via optical transmission in the far-infrared (IR) (50-7000 cm(-1)). A Drude model was fitted to the changes in the far-IR conductivity to quantify the additional free carrier concentration induced by the B-doping. PMID:21386503

Liu, X M; Gutiérrez, H R; Eklund, P C

2010-08-25

248

Increasing strengths of boron fiber and graphite fiber plastic composites. Final report May--Dec 1971  

Microsoft Academic Search

Prestressing of boron\\/epoxy prepreg tape material yields composites with substantial improvements in both average tensile strength and standard deviation over that obtained with conventional prepreg to laminate processing. The process has a fundamental effect on the prepreg fiber strength properties by prebreaking the fibers at their weak sites, and these induced changes are then carried into the composite as a

G. J. Mills; W. M. Wochos; G. G. Brown

1971-01-01

249

Synthesis and properties of boron doped ZnO nanorods on silicon substrate by low-temperature hydrothermal reaction  

NASA Astrophysics Data System (ADS)

Boron doped ZnO nanorods were fabricated by hydrothermal technique on silicon substrate covered with a ZnO seed layer. It is found that the concentration of boric acid in the reaction solution plays a key role in varying the morphology and properties of the products. The growth rate along the [0 0 0 1] orientation (average size in diameter) of the doped ZnO nanorods decreased (increased) with the increase of boric acid concentration. Based on the results of XRD, EDX and XPS, it is demonstrated that the boron dopants tend to occupy the octahedral interstice sites. The photoluminescence of the ZnO nanorods related to boron doping are investigated.

Yu, Qi; Li, Liuan; Li, Hongdong; Gao, Shiyong; Sang, Dandan; Yuan, Jujun; Zhu, Pinwen

2011-05-01

250

Boron, graphite, glass, metal and aramid fiber reinforced plastics. January, 1973-May, 1981 (Citations from the Rubber and Plastics Research Association Data Base). Report for January 1973-May 1981  

SciTech Connect

The citations cover information about advanced reinforced composites such as boron, graphite, glass, metal, and aramid. Topics include applications, fabrication processes, proerties, nondestructive testing, and economics of composite materials. (Contains 90 citations fully indexed and including a title list.)

Not Available

1981-05-01

251

Plasma Synthesized Doped Boron Nanopowder for MgB2 Superconductors  

SciTech Connect

Under this program, a process to synthesize nano-sized doped boron powder by a plasma synthesis process was developed and scaled up from 20 gram batches at program start to over 200 grams by program end. Over 75 batches of boron nanopowder were made by RF plasma synthesis. Particle sizes were typically in the 20-200 nm range. The powder was synthesized by the reductive pyrolysis of BCl{sub 3} in hydrogen in an RF plasma. A wide range of process parameters were investigated including plasma power, torch geometry, gas flow rates, and process pressure. The powder-in-tube technique was used to make monofilament and multifilament superconducting wires. MgB{sub 2} wire made with Specialty Materials plasma synthesized boron nanopowder exhibited superconducting properties that significantly exceeded the program goals. Superconducting critical currents, J{sub c}, in excess of 10{sup 5} A cm{sup -2} at magnetic fields of 8 tesla were reproducibly achieved. The upper critical magnetic field in wires fabricated with program boron powder were H{sub c2}(0) = 37 tesla, demonstrating the potential of these materials for high field magnet applications. T{sub c} in carbon-doped MgB{sub 2} powder showed a systematic decrease with increasing carbon precursor gas flows, indicating the plasma synthesis process can give precise control over dopant concentrations. Synthesis rates increased by a factor of 400% over the course of the program, demonstrating the scalability of the powder synthesis process. The plasma synthesis equipment at Specialty Materials has successfully and reproducibly made high quality boron nanopowder for MgB{sub 2} superconductors. Research and development from this program enabled Specialty Materials to successfully scale up the powder synthesis process by a factor of ten and to double the size of its powder pilot plant. Thus far the program has been a technical success. It is anticipated that continued systematic development of plasma processing parameters, dopant chemistry and concentration, wire processing technology, and collection technology will lead to the commercialization of boron nanopowder as a precursor for MgB{sub 2} superconductors. Potential commercial applications include magnets for magnetic resonance imaging (MRI), fault current limiters, wind turbine generators.

James V. Marzik

2012-03-26

252

Self-compensation property of ?-rhombohedral boron doped with high Li concentration  

NASA Astrophysics Data System (ADS)

A high concentration of Li (up to LiB5.8; 18 Li/cell) was doped into ?-rhombohedral boron (?-B), which has a crystalline structure built up from B12 icosahedral clusters, by sealing the raw materials in a stainless-steel tube. The relation between the structure and the electronic properties was clarified and a self-compensation property of Li- or Mg-doped ?-B was discussed. The Li concentration was analyzed by atomic absorption spectrometry. The changes in the structure and the electronic properties were investigated by X-ray diffraction using the Rietveld method and by electrical conductivity measurements, respectively. Li occupies the A1, D, E and F sites, and the occupancies of the B sites (B13, B16 and B4) decrease with increasing Li doping. In Li- or Mg-doped ?-B, electron doping is compensated by the removal of interstitial B atoms at the B16 site and by the generation of vacancies at the B13 and B4 sites. There have been no reports of self-compensation in other crystalline elemental semiconductors.

Hyodo, H.; Nezu, A.; Soga, K.; Kimura, K.

2012-11-01

253

Neutral and charged boron-doped fullerenes for CO2 adsorption.  

PubMed

Recently, the capture and storage of CO2 have attracted research interest as a strategy to reduce the global emissions of greenhouse gases. It is crucial to find suitable materials to achieve an efficient CO2 capture. Here we report our study of CO2 adsorption on boron-doped C60 fullerene in the neutral state and in the 1e (-)-charged state. We use first principle density functional calculations to simulate the CO2 adsorption. The results show that CO2 can form weak interactions with the BC59 cage in its neutral state and the interactions can be enhanced significantly by introducing an extra electron to the system. PMID:24778968

de Silva, Suchitra W; Du, Aijun; Senadeera, Wijitha; Gu, Yuantong

2014-01-01

254

Neutral and charged boron-doped fullerenes for CO2 adsorption  

PubMed Central

Summary Recently, the capture and storage of CO2 have attracted research interest as a strategy to reduce the global emissions of greenhouse gases. It is crucial to find suitable materials to achieve an efficient CO2 capture. Here we report our study of CO2 adsorption on boron-doped C60 fullerene in the neutral state and in the 1e ?-charged state. We use first principle density functional calculations to simulate the CO2 adsorption. The results show that CO2 can form weak interactions with the BC59 cage in its neutral state and the interactions can be enhanced significantly by introducing an extra electron to the system.

de Silva, Suchitra W; Du, Aijun; Senadeera, Wijitha

2014-01-01

255

Photovoltaic Device Including A Boron Doping Profile In An I-Type Layer  

DOEpatents

A photovoltaic cell for use in a single junction or multijunction photovoltaic device, which includes a p-type layer of a semiconductor compound including silicon, an i-type layer of an amorphous semiconductor compound including silicon, and an n-type layer of a semiconductor compound including silicon formed on the i-type layer. The i-type layer including an undoped first sublayer formed on the p-type layer, and a boron-doped second sublayer formed on the first sublayer.

Yang, Liyou (Lawrenceville, NJ)

1993-10-26

256

Electron-beam-induced currents on beryllium-doped cubic boron nitride single crystal  

Microsoft Academic Search

The electrical properties of a beryllium-doped cubic boron nitride (c-BN) single crystal grown on (111) diamond were investigated by using electron-beam-induced current measurements as well as current–voltage (I–V) and capacitance–voltage measurements. The I–V measurements through silver electrodes on c-BN showed non-linear characteristics, revealing Schottky behavior. From the temperature dependence of resistivity, the activation energy of 0.24eV was obtained. We observed

Hajime Tomokage; Naoki Nomura; Takashi Taniguchi; Toshihiro Ando

2000-01-01

257

Density functional investigation of CO adsorption on Ni-doped single-walled armchair (5,5) boron nitride nanotubes.  

PubMed

The adsorption of CO onto Ni-doped boron nitride nanotubes (BNNTs) was investigated using density functional theory at the B3LYP/LanL2DZ level of theory. The structures of the Ni-doped BNNTs and their CO-adsorbed configurations were obtained. It was found that the strength of adsorption of CO onto Ni-doped perfect BNNTs is higher than that on defective BNNTs. The electronic properties of all of the adsorption configurations of CO on Ni-doped BNNTs are reported. PMID:22864627

Tontapha, Sarawut; Ruangpornvisuti, Vithaya; Wanno, Banchob

2013-01-01

258

Chemisorption of Transition-Metal Atoms on Boron- and Nitrogen-Doped Carbon Nanotubes: Energetics and Geometric and Electronic Structures  

SciTech Connect

The well-defined binding between transition-metals (TM) and the sidewall of carbon nanotubes (CNTs) plays a key role in the performance of CNT-based anoelectronics, as well as the stability of catalysts used in either heterogeneous catalysis or fuel-cell electrocatalysis. Spin-polarized density functional theory calculations demonstrate that either boron or nitrogen doping can increase the binding strength of TM atoms with singlewall carbon nanotubes (SWCNTs), and comparatively, boron doping is more effective. The binding nature can be identified as chemisorption, based on the magnitude of the binding energy and the formation of multiple bonds. The chemisorbed TM atoms can modify the electronic structure of the doped nanotubes in various ways, depending upon the TM and helicity of the CNT, rendering the TM/doped-SWCNT composite viable for a wide range of applications. A total of 11 technologically relevant TMs adsorbed on two distinct and stable doped-SWCNT models have been investigated in this study. The doping sites are arranged in either a locally concentrated or uniform fashion within semiconducting SWCNT(8,0) and metallic SWCNT(6,6). The results serve as a starting point for studying larger, more complex TM nanostructures anchored on the sidewall of boron- or nitrogen-doped CNTs.

An, Wei; Turner, C. H.

2009-04-30

259

Influence of growth pressure on the electrical properties of boron-doped polycrystalline diamond films  

NASA Astrophysics Data System (ADS)

Heavily boron-doped diamond films are synthesized by the hot-filament chemical vapor deposition method under the gas mixtures of H 2, CH 4 and trimethyl borate. The measurement results of scanning electron microscopy, Raman spectroscopy, X-ray diffractometer and electrical properties showed the morphologies, microstructures, carrier concentration and superconducting transition temperature for as-grown diamond films were dependent on the change of growth pressure, and specially its carrier concentrations could be adjusted from 10 19 to 10 21 cm -3 by increasing growth pressures from 2.5 to 5 kPa. And further, the effects of growth pressure on the film microstructural property and the doping level dependence of the superconducting transition temperature were discussed.

Wang, Z. L.; Lu, C.; Li, J. J.; Gu, C. Z.

2009-09-01

260

Optoelectronic surface-related properties in boron-doped and irradiated diamond thin films  

NASA Astrophysics Data System (ADS)

Elucidation of microscopic properties of synthetic diamond films, such as formation and evolution of bulk and surface defects, chemistry of dopants, is necessary for a reliable quality control and reproducibility in applications. Surface photovoltage (SPV) spectroscopy and photoluminescence (PL) spectroscopy were employed to study diamond thin films grown on silicon by microwave plasma-assisted chemical vapor deposition and hot-filament chemical vapor deposition with different levels of boron doping in conjunction with gamma irradiation. SPV experiments showed that while the increase of boron concentration leads to a semiconductor-metal transition, subsequent gamma irradiation reverts quasi-metallic samples back to a semiconducting state by compensating electrical activity of boron possibly via hydrogen. One of the most pronounced common transitions observed at ~3.1-3.2 eV in the SPV spectra was also present in all of the PL spectra. It is likely that this is a signature of the sp2-hybridized carbon clusters in or in the vicinity of grain boundaries.

Nemashkalo, A.; Chapagain, P. R.; Peters, R. M.; Farmer, J.; Gupta, S.; Strzhemechny, Y. M.

2012-01-01

261

Electrochemical behavior of triflusal, aspirin and their metabolites at glassy carbon and boron doped diamond electrodes.  

PubMed

The electrochemical behavior of triflusal (TRF) and aspirin (ASA), before and after hydrolysis in water and in alkaline medium using two different electrode surfaces, glassy carbon and boron doped diamond, was study by differential pulse voltammetry over a wide pH range. The hydrolysis products are 2-(hydroxyl)-4-(trifluoromethyl)-benzoic acid (HTB) for triflusal and salicylic acid (SA) for aspirin, which in vivo represent their main metabolites. The hydrolysis processes were also followed by spectrophotometry. The UV results showed complete hydrolysis after one hour for TRF and after two hours for ASA in alkaline solution. The glassy carbon electrode enables only indirect determination of TRF and ASA through the electrochemical detection of their hydrolysis products HTB and SA, respectively. The oxidation processes of HTB and SA are pH dependent and involve different numbers of electrons and protons. Moreover, the difference between the oxidation peak potential of SA and HTB was equal to 100 mV in the studied pH range from 1 to 8 due to the CF3 of the aromatic ring of HTB molecule. Due to its wider oxidation potential range, the boron doped diamond electrode was used to study the direct oxidation of TRF and ASA, as well as of their respective metabolites HTB and SA. PMID:20402644

Enache, Teodor Adrian; Fatibello-Filho, Orlando; Oliveira-Brett, Ana Maria

2010-08-01

262

Moessbauer spectroscopy and electrical conductivity of Fe-doped {beta}-rhombohedral boron  

SciTech Connect

Iron and/or aluminum are doped to {beta}-rhombohedral boron, and the electrical conductivity and {sup 57}Fe Moessbauer effect are measured. The temperature dependence of the electrical conductivity is explained as a variable range hopping type. The conductivity increases with an increase in Fe concentration, but it is insensitive to Al concentration. The Moessbauer spectra measured at room temperature are resolved into three kinds of doublets and a sextet due to ferromagnetic FeB. One doublet, {gamma}{sub 0}, is attributed to Fe{sup 3+} ions at A{sub 1} sites, while the others, {gamma}{sub 1} and {gamma}{sub 2}, occur from Fe{sup 2+} ions at D sites. When Fe and Al atoms are simultaneously doped into {beta}-boron, the intensity of the {gamma}{sub 0} doublet decreases and, hence, those of the {gamma}{sub 1} and {gamma}{sub 2} doublets relatively increase. The results shows that Fe atoms are moved from A{sub 1} corresponds to Fe{sup 2+} (D)-Fe{sup 2+}(D) and the {gamma}{sub 2} doublet to Fe{sup 2+}(D) and that a part of Fe{sup 2+}(D) is in the magnetic state at 4.2 K.

Nakayama, Takahiro; Matsuda, Hirofumi; Kimura, Kaoru; Ino, Hiromitsu [Univ. of Tokyo (Japan)] [Univ. of Tokyo (Japan)

1997-10-01

263

Electron-beam-induced substitutional carbon doping of boron nitride nanosheets, nanoribbons, and nanotubes.  

PubMed

Substitutional carbon doping of the honeycomb-like boron nitride (BN) lattices in two-dimensional (nanosheets) and one-dimensional (nanoribbons and nanotubes) nanostructures was achieved via in situ electron beam irradiation in an energy-filtering 300 kV high-resolution transmission electron microscope using a C atoms feedstock intentionally introduced into the microscope. The C substitutions for B and N atoms in the honeycomb lattices were demonstrated through electron energy loss spectroscopy, spatially resolved energy-filtered elemental mapping, and in situ electrical measurements. The preferential doping was found to occur at the sites more vulnerable to electron beam irradiation. This transformed BN nanostructures from electrical insulators to conductors. It was shown that B and N atoms in a BN nanotube could be nearly completely replaced with C atoms via electron-beam-induced doping. The doping mechanism was proposed to rely on the knockout ejections of B and N atoms and subsequent healing of vacancies with supplying C atoms. PMID:21425863

Wei, Xianlong; Wang, Ming-Sheng; Bando, Yoshio; Golberg, Dmitri

2011-04-26

264

Half-Metallicity in Undoped and Boron Doped Graphene Nanoribbons in the Presence of Semilocal Exchange-Correlation Interactions  

Microsoft Academic Search

We perform density functional calculations on one-dimensional zigzag edge graphene nano-ribbons (ZGNRs) of different widths, with and without edge doping including semi-local exchange-correlations. Our study reveals that, although the ground state of edge passivated (with hydrogen) ZGNRs prefers to be anti-ferromagnetic, the doping of both the edges with Boron atoms stabilizes the system in a ferromagnetic ground state. Both the

Sudipta Dutta; Swapan K. Pati

2008-01-01

265

Morphological and microstructural stability of boron-doped diamond thin film electrodes in an acidic chloride medium at high anodic current densities  

SciTech Connect

Boron-doped diamond thin films have been examined before and after high-current-density electrolysis to investigate the morphological and microstructural stability of this new electrode material. The diamond thin films were used to generate chlorine from a solution of 1.0 M HNO{sub 3} + 2.0 M NaCl at current densities of 0.05 and 0.5 A/cm{sup 2} for times up to 20 h. Comparative studies were made using common graphitic electrodes including highly oriented pyrolytic graphite, glassy carbon, and Grafoil{reg_sign}. The electrodes were characterized using four-point probe resistivity measurements, atomic force microscopy, scanning electron microscopy, Raman spectroscopy, x-ray photoelectron spectroscopy, and cyclic voltammetry. In all cases, no severe morphological or microstructural damage (i.e., corrosion) was observed on films exposed to the highest current density. There were surface compositional changes in the forms of oxygenation and non-diamond carbon impurity etching that produced an increase in the reaction overpotential. Specifically, the overpotential was supposed to result from a combination of decreased surface conductivity due to the formation of carbon-oxygen functional groups and loss of kinetically active redox sites due to the oxidative etching of nondiamond carbon impurities.

Chen, Q.; Granger, M.C.; Lister, T.E.; Swain, G.M. [Utah State Univ., Logan, UT (United States). Dept. of Chemistry and Biochemistry

1997-11-01

266

Geometric, electronic, and optical properties of a boron-doped aluminum cluster of BAl21-: A density functional theory study  

NASA Astrophysics Data System (ADS)

We present the physicochemical properties for the lowest-energy isomer of a boron-doped aluminum cluster of BAl21-. The isomer was obtained by basin-hopping minimization based on the density functional theory, starting from a face-sharing bi-icosahedral structure in which two boron atoms were endohedrally doped to each icosahedron. The lowest-energy isomer is a triangular form in which an aluminum cage encapsulates two boron atoms endohedrally. The electronic structure was analyzed by projecting Kohn-Sham orbitals onto the spherical harmonics; occupied and unoccupied frontier orbitals are dominantly G- and H-symmetries, respectively. Optical absorption is mainly assigned to G to H transitions.

Iwasa, Takeshi; Nakajima, Atsushi

2013-09-01

267

Undoped and boron doped diamond nanoparticles as platinum and platinum-ruthenium catalyst support for direct methanol fuel cell application  

Microsoft Academic Search

Nanoparticular diamond is a promising material that can be used as a robust and chemically stable catalytic support. It has been studied and characterized physically and electrochemically, in its powder and thin film forms. This thesis work intends to demonstrate that undoped diamond nanoparticles (DNPs) and boron-doped diamond nanoparticles (BDDNPs) can be used as an electrode and a catalytic support

Lyda La Torre Riveros

2010-01-01

268

Electrochemical oxidation of 3-methylpyridine at a boron-doped diamond electrode: application to electroorganic synthesis and wastewater treatment  

Microsoft Academic Search

The electrochemical oxidation of 3-methylpyridine (3-MP) at synthetic boron-doped diamond (BDD) thin film electrode has been studied in acid media by cyclic voltammetry and bulk electrolysis. The results have shown that in the potential region of water stability there can occur direct electron transfer reactions on BDD surface that result in electrode fouling due to the formation of a polymeric

J. Iniesta; P. A. Michaud; M. Panizza; Ch. Comninellis

2001-01-01

269

Enhanced electrochemical response of boron-doped diamond electrodes brought on by a cathodic surface pre-treatment  

Microsoft Academic Search

The effect of surface pre-treatment on the electrochemical response of boron-doped diamond (BDD) electrodes is reported. Initially, several examples from published works illustrate the dramatic changes observed when a cathodic polarisation is applied before measurements instead of the classically adopted anodic treatment. In particular, electroanalytical determinations of pesticides in pure and contaminated waters could only be possible after holding the

Hugo B. Suffredini; Valber A. Pedrosa; Lúcia Codognoto; Sérgio A. S. Machado; Romeu C. Rocha-Filho; Luis A. Avaca

2004-01-01

270

High-Temperature Point-Contact Transistors and Schottky Diodes Formed on Synthetic Boron-Doped Diamond.  

National Technical Information Service (NTIS)

Point-contact transistors and Schottky diodes have been formed on synthetic boron-doped diamond. This is the first report of diamond transistors that have power gain. Further, the transistors exhibited power gain at 510 C and the Schottky diodes were oper...

M. W. Geis D. D. Rathman D. J. Ehrlich R. A. Murphy W. T. Lindley

1987-01-01

271

Amperometric glucose sensor based on enzyme-modified boron-doped diamond electrode by cross-linking method  

Microsoft Academic Search

A novel and robust amperometric enzyme electrode for the detection of glucose has been constructed by immobilizing glucose oxidase (GOD) on a boron-doped diamond (BDD) electrode with a cross-linking technique. Cyclic voltammograms were used to characterize the enzyme electrode. The response was evaluated with respect to the enzyme amount on the electrode and the concentration of BSA used in the

Lei Su; Xinping Qiu; Lianghong Guo; Fushi Zhang; Chenhe Tung

2004-01-01

272

Comparative electrochemical degradation of the triphenylmethane dye Methyl Violet with boron-doped diamond and Pt anodes  

Microsoft Academic Search

The electrochemical degradation of the triphenylmethane dye Methyl Violet (MV) in acidic and neutral aqueous solutions has been comparatively studied in an undivided electrolytic cell containing either a boron-doped diamond (BDD) or Pt anode and a stainless steel cathode under galvanostatic conditions. The dye solutions are completely decolorized and mineralized using BDD, but both processes become much slower when using

Morched Hamza; Ridha Abdelhedi; Enric Brillas; Ignasi Sirés

2009-01-01

273

High-temperature point-contact transistors and Schottky diodes formed on synthetic boron-doped diamond  

Microsoft Academic Search

Point-contact transistors and Schottky diodes have been formed on synthetic boron-doped diamond. This is the first report of diamond transistors that have power gain. Further, the transistors exhibited power gain at 510°C and the Schottky diodes were operational at 700°C.

M. W. Geis; D. D. Rathman; D. J. Ehrlich; R. A. Murphy; W. T. Lindley

1987-01-01

274

Stability of graphitic-like zinc oxide layers under carriers doping: a first-principles study  

NASA Astrophysics Data System (ADS)

Although theoretical works have demonstrated that (0001) polar films of wurtzite (WZ) ZnO automatically transform into graphitic-like (GP) structures, the experimental realization of GP ZnO is limited to a thickness of several atomic layers. Here, using first-principles calculations, we demonstrated that the stability of GP ZnO is closely related to the concentration of near-free carriers. Our results show that the doped carriers, originating from the rich oxygen vacancies, can effectively screen the polar field, and stabilize the WZ structure. Thus, in order to obtain GP ZnO layers with much thicker films, it is necessary to reduce the near-free carrier concentration.

Kan, Erjun; Deng, Kaiming; Wu, Fang

2013-11-01

275

Can trans-polyacetylene be formed on single-walled carbon-doped boron nitride nanotubes?  

PubMed

Recently, the grafting of polymer chains onto nanotubes has attracted increasing attention as it can potentially be used to enhance the solubility of nanotubes and in the development of novel nanotube-based devices. In this article, based on density functional theory (DFT) calculations, we report the formation of trans-polyacetylene on single-walled carbon-doped boron nitride nanotubes (BNNTs) through their adsorption of a series of C(2)H(2) molecules. The results show that, rather than through [2 + 2] cycloaddition, an individualmolecule would preferentially attach to a carbon-doped BNNT via "carbon attack" (i.e., a carbon in the C(2)H(2) attacks a site on the BNNT). The adsorption energy gradually decreases with increasing tube diameter. The free radical of the carbon-doped BNNT is almost completely transferred to the carbon atom at the end of the adsorbed C(2)H(2) molecule. When another C(2)H(2) molecule approaches the carbon-doped BNNT, it is most energetically favorable for this C(2)H(2) molecule to be adsorbed at the end of the previously adsorbed C(2)H(2) molecule, and so on with extra C(2)H(2) molecules, leading to the formation of polyacetylene on the nanotube. The spin of the whole system is always localized at the tip of the polyacetylene formed, which initiates the adsorption of the incoming species. The present results imply that carbon-doped BNNT is an effective "metal-free" initiator for the formation of polyacetylene. PMID:22271098

Chen, Ying; Wang, Hong-xia; Zhao, Jing-xiang; Cai, Qing-hai; Wang, Xiao-guang; Wang, Xuan-zhang

2012-07-01

276

The effect of surface treatment on the electrical properties of metal contacts to boron-doped homoepitaxial diamond film  

SciTech Connect

Both doped and undoped homoepitaxial diamond films were fabricated using microwave plasma-enhanced chemical vapor deposition (CVD). The conductivity of the diamond film is strongly affected by the surface treatment. In particular, exposure of film surface to a hydrogen plasma results in the formation of a conductive layer which can be used to obtain linear (ohmic) {ital I-V} characteristics of the Au/diamond contacts, regardless of the doping level. The proper chemical cleaning of the boron-doped homoepitaxial diamond surface allows the fabrication of Au-gate Schottky diodes with excellent rectifying characteristics at temperatures of at least 400{degrees}C.

Grot, S.A.; Gildenblat, G.S.; Hatfield, C.W.; Wronski, C.R. (Pennsylvania State Univ., University Park, PA (USA). Dept. of Electrical Engineering); Badzian, A.R.; Badzian, T.; Messier, R. (Pennsylvania State Univ., University Park, PA (USA). Materials Research Lab.)

1990-02-01

277

Atmospheric pressure chemical vapour deposition of boron doped titanium dioxide for photocatalytic water reduction and oxidation.  

PubMed

Boron-doped titanium dioxide (B-TiO2) films were deposited by atmospheric pressure chemical vapour deposition of titanium(iv) chloride, ethyl acetate and tri-isopropyl borate on steel and fluorine-doped-tin oxide substrates at 500, 550 and 600 °C, respectively. The films were characterised using powder X-ray diffraction (PXRD), which showed anatase phase TiO2 at lower deposition temperatures (500 and 550 °C) and rutile at higher deposition temperatures (600 °C). X-ray photoelectron spectroscopy (XPS) showed a dopant level of 0.9 at% B in an O-substitutional position. The ability of the films to reduce water was tested in a sacrificial system using 365 nm UV light with an irradiance of 2 mW cm(-2). Hydrogen production rates of B-TiO2 at 24 ?L cm(-2) h(-1) far exceeded undoped TiO2 at 2.6 ?L cm(-2) h(-1). The B-TiO2 samples were also shown to be active for water oxidation in a sacrificial solution. Photocurrent density tests also revealed that B-doped samples performed better, with an earlier onset of photocurrent. PMID:23999866

Carmichael, Penelope; Hazafy, David; Bhachu, Davinder S; Mills, Andrew; Darr, Jawwad A; Parkin, Ivan P

2013-10-21

278

Can CO2 molecule adsorb effectively on Al-doped boron nitride single walled nanotube?  

NASA Astrophysics Data System (ADS)

The adsorption of carbon dioxides (CO2) is very important in environmental and industrial applications. The boron nitride nanotube (BNNT) with large surface and polarity may be a good candidate as CO2 capture. Unfortunately, the pristine BNNT is almost inert to the highly stable CO2. To renew technical applications of BNNT for CO2 adsorption, we explore the possibility of CO2 adsorption on various (n, 0) (n = 6, 8, 10, 12 and 14) Al-doped BNNT by density functional theory (DFT) calculations. The results show that the Al-doped BNNT could be a potential CO2 adsorption material, and the CO2 adsorption energies are independent of BNNT diameters. Furthermore, the interactions between CO2 and exemplified (6, 0) Al-doped BNNT are investigated by density of states (DOS) and electron density. We found the interaction between CO2 and AlB-BNNT is stronger than that of CO2 and AlN-BNNT. The adsorption of CO2 can induce new density of state, as well as a local charge fluctuation due to more electron density redistribution on the atoms near CO2 molecule.

Shao, Peng; Kuang, Xiao-Yu; Ding, Li-Ping; Yang, Jing; Zhong, Ming-Min

2013-11-01

279

Investigation on cubic boron nitride crystals doped with Si by high temperature thermal diffusion  

NASA Astrophysics Data System (ADS)

The method of high temperature thermal diffusion was successfully applied for doping Si impurities into cubic boron nitride (cBN) crystals. X-ray photoelectron spectra (XPS) and the current-voltage (I-V) characteristics at different temperatures were respectively used for analyzing the chemical states and the activation energy of Si impurity in cBN. According to the XPS results, Si impurities mainly replace B atoms bonding with the adjacent N atoms and become donors in cBN. Without surface cleaning, there are a lot of C and O contaminations on the surface of cBN, so a small quantity of C-Si and Si-N-O bonds also exist at the surface of cBN. Most Si impurities distribute in the shallow layer underneath the surface of cBN. Based on the electric measurement, Si impurities in cBN usually have the activation energy beyond 0.4 eV, and they can only be slightly ionized at room temperature, therefore the resistivity of Si-doped cBN is still high, and the space charge limited current becomes the main conductive mechanism in cBN. However, the conductivity of Si-doped cBN can rapidly increase with the temperature. In addition, the activation energy and the concentration of Si impurity in cBN can be affected by the temperature and the time of thermal diffusion, which needs to be verified further.

Li, Xinlu; Feng, Shuang; Liu, Xiuhuan; Hou, Lixin; Gao, Yanjun; Wang, Qi; Liu, Nian; Zhang, Hai; Chen, Zhanguo; Zheng, Jie; Jia, Gang

2014-07-01

280

Fabrication, structure, and photocatalytic activities of boron-doped ZnO nanorods hydrothermally grown on CVD diamond film  

NASA Astrophysics Data System (ADS)

The boron (B)-doped zinc oxide nanorods (ZnO NRs) have been fabricated on chemical vapor deposited (CVD) diamond film by hydrothermal technique. The mean diameter of the B-doped ZnO NRs is larger than that of the undoped NRs. The results of X-ray diffraction and first-principles calculations demonstrate that the boron atoms prefer to occupy the octahedral interstice positions of ZnO, which lead to the lattice expansion and band gap shrinkage. The rectifying B-doped ZnO NRs/p-diamond heterojunction structure has been performed to degrade reactive yellow 15 solution, showing a high performance photocatalysis. The photocatalysis mechanism based on the pn heterojunction is discussed.

Yu, Qi; Li, Jia; Li, Hongdong; Wang, Qiliang; Cheng, Shaoheng; Li, Liuan

2012-06-01

281

Scanning tunneling microscopy simulations of nitrogen- and boron-doped graphene and single-walled carbon nanotubes.  

PubMed

We report on studies of electronic properties and scanning tunneling microscopy (STM) of the most common configurations of nitrogen- or boron-doped graphene and carbon nanotubes using density functional theory. Charge transfer, shift of the Fermi level, and localized electronic states are analyzed as a function of the doping configurations and concentrations. The theoretical STM images show common fingerprints for the same doping type for graphene, and metallic or semiconducting nanotubes. In particular, nitrogen is not imaged in contrast to boron. STM patterns are mainly shaped by local density of states of the carbon atoms close to the defect. STM images are not strongly dependent on the bias voltage when scanning the defect directly. However, the scanning of the defect-free side of the tube displays a perturbation compared to the pristine tube depending on the applied bias. PMID:20552993

Zheng, Bing; Hermet, Patrick; Henrard, Luc

2010-07-27

282

Label-free detection of lectins on carbohydrate-modified boron-doped diamond surfaces.  

PubMed

This paper describes the label-free detection of carbohydrate-lectin interactions. The sensor consists of a boron-doped diamond (BDD) electrode terminated with alkynyl surface groups, which have been functionalized via the CuACC (copper(I)-catalyzed azide-alkyne cycloaddition) "click" reaction with carbohydrate analogues bearing an azido-terminating arm. In this work, electrochemical impedance spectroscopy (EIS) was used as an effective technique to probe the specific interactions of the surface-bound carbohydrates with their complementary lectin partners, and the response was found to be dependent on the relative density of sugar units immobilized on the BDD surface. A BDD interface with 60% surface-bound mannose showed a detection limit of ?5 ± 0.5 nM for Lens culinaris lectin, with an affinity constant of K(A) = (2.63 ± 0.5) × 10(6) M(-1). PMID:20828205

Szunerits, Sabine; Niedzio?ka-Jönsson, Joanna; Boukherroub, Rabah; Woisel, Patrice; Baumann, Jean-Sébastien; Siriwardena, Aloysius

2010-10-01

283

In vivo assessment of cancerous tumors using boron doped diamond microelectrode  

NASA Astrophysics Data System (ADS)

The in vitro and in vivo electrochemical detection of the reduced form of glutathione (L-?-glutamyl-L-cysteinyl-glycine, GSH) using boron doped diamond (BDD) microelectrode for potential application in the assessment of cancerous tumors is presented. Accurate calibration curve for the determination of GSH could be obtained by the in vitro electrochemical measurements. Additionally, it was shown that it was possible to separate the detection of GSH from the oxidized form of glutathione (GSSG) using chronoamperometry measurements. In vivo GSH detection measurements have been performed in human cancer cells inoculated in immunodeficient mice. These measurements have shown that the difference of GSH level between cancerous and normal tissues can be detected. Moreover, GSH detection measurements carried out before and after X-ray irradiation have proved that it is possible to assess in vivo the decrease in GSH concentration in the tumor after a specific treatment.

Fierro, Stéphane; Yoshikawa, Momoko; Nagano, Osamu; Yoshimi, Kenji; Saya, Hideyuki; Einaga, Yasuaki

2012-11-01

284

Electronic structure of carbon doped boron nitride nanotubes: a first-principles study.  

PubMed

We determine atomic and electronic structures of arm-chair and zigzag boron nitride nanotubes (BN-NTs) of different diameters using first-principles pseudopotential-based density functional theory calculations. We find that the structure of BN-NTs in bundled form is slightly different from that of the isolated BN-NTs, reflecting on the inter-tube interactions. Effects of carbon doping on the electronic structure of (5,5) and (5,0) BN-NTs are determined: carbon substitution either at B-site, being energetically very stable, or at N-site can yield magnetically polarized semiconducting state, whereas carbon substitution at neighbouring B and N sites yields a non-magnetic insulating structure. PMID:19049174

Kahaly, Mousumi Upadhyay; Waghmare, Umesh V

2008-08-01

285

Measurement of electron affinity in boron-doped diamond from capacitance spectroscopy  

SciTech Connect

Boron-doped diamond film sample has been grown on (100) silicon substrate using the microwave enhanced chemical vapor deposition method. It is found that the sample has very good material qualities and an excellent (100) surface morphology. Au/diamond Schottky was fabricated on the (100) surface to study electron affinity of the diamond sample. By measuring frequency dependence capacitance{endash}voltage spectroscopy of the Schottky sample in high vacuum and at room temperature, a very small electron affinity of about 0.025 eV and a work function of about 5.165 eV have been obtained for the (100) surface of the diamond sample supposing the diamond band gap energy is 5.5 eV. {copyright} {ital 1997 American Institute of Physics.}

Liu, K.; Zhang, B.; Wan, M.; Chu, J.H. [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Academia Sinica, 420 Zhong Shan Bei Yi Road, Shanghai 200083, Peoples Republic of (China)] [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Academia Sinica, 420 Zhong Shan Bei Yi Road, Shanghai 200083, Peoples Republic of (China); Johnston, C. [AEA Technology, 552 Harwell, Didcot, Oxfordshire OX11 0RA (United Kingdom)] [AEA Technology, 552 Harwell, Didcot, Oxfordshire OX11 0RA (United Kingdom); Roth, S. [MPI fur Festkorperforschung, D-70569 Stuttgart (Germany)] [MPI fur Festkorperforschung, D-70569 Stuttgart (Germany)

1997-05-01

286

Simultaneous detection of iodine and iodide on boron doped diamond electrodes.  

PubMed

Individual and simultaneous electrochemical detection of iodide and iodine has been performed via cyclic voltammetry on boron doped diamond (BDD) electrodes in a 1M NaClO(4) (pH 8) solution, representative of typical environmental water conditions. It is feasible to compute accurate calibration curve for both compounds using cyclic voltammetry measurements by determining the peak current intensities as a function of the concentration. A lower detection limit of about 20 ?M was obtained for iodide and 10 ?M for iodine. Based on the comparison between the peak current intensities reported during the oxidation of KI, it is probable that iodide (I(-)) is first oxidized in a single step to yield iodine (I(2)). The latter is further oxidized to obtain IO(3)(-). This technique, however, did not allow for a reasonably accurate detection of iodate (IO(3)(-)) on a BDD electrode. PMID:23200355

Fierro, Stéphane; Comninellis, Christos; Einaga, Yasuaki

2013-01-15

287

In vivo assessment of cancerous tumors using boron doped diamond microelectrode  

PubMed Central

The in vitro and in vivo electrochemical detection of the reduced form of glutathione (L-?-glutamyl-L-cysteinyl-glycine, GSH) using boron doped diamond (BDD) microelectrode for potential application in the assessment of cancerous tumors is presented. Accurate calibration curve for the determination of GSH could be obtained by the in vitro electrochemical measurements. Additionally, it was shown that it was possible to separate the detection of GSH from the oxidized form of glutathione (GSSG) using chronoamperometry measurements. In vivo GSH detection measurements have been performed in human cancer cells inoculated in immunodeficient mice. These measurements have shown that the difference of GSH level between cancerous and normal tissues can be detected. Moreover, GSH detection measurements carried out before and after X-ray irradiation have proved that it is possible to assess in vivo the decrease in GSH concentration in the tumor after a specific treatment.

Fierro, Stephane; Yoshikawa, Momoko; Nagano, Osamu; Yoshimi, Kenji; Saya, Hideyuki; Einaga, Yasuaki

2012-01-01

288

Electrodeposition of metal adlayers on boron-doped diamond thin-film electrodes  

SciTech Connect

A preliminary investigation of the electrochemical deposition of Pt, Pb, and Hg adlayers on conductive diamond thin-film surfaces ha been made using cyclic voltammetry and scanning electron microscopy. The diamond thin films employed were polycrystalline, grown on conductive Si substrates (1 cm{sup 2}) to a thickness of ca. 14 {mu}m, and doped with boron at a nominal atomic concentration ranging between 10{sup 19} and 10{sup 20} cm{sup {minus}3}. The cyclic volammetric measurements were performed both in a conventional glass electrochemical cell and in thin-layer flow cell. The results demonstrate that metallization of diamond film surfaces electrochemically is feasible, opening the door of the development of novel catalytic electrodes, sensors, and detectors using this advanced material.

Awada, M.; Strojek, J.W.; Swain, G.M. [Utah State Univ., Logan, UT (United States). Dept. of Chemistry and Biochemistry

1995-03-01

289

Conductive polymer-modified boron-doped diamond for DNA hybridization analysis  

NASA Astrophysics Data System (ADS)

In this paper, we study the immobilization of DNA on boron-doped diamond (BDD) thin films for DNA hybridization analysis. Taking advantage of the conducting nature of the BDD film, a thin layer of polyaniline/poly (acrylic acid) (PANI/PAA) composite polymer film could be readily electropolymerized onto the diamond surface. The carboxylic acid residues in the polymer film act as the binding sites for DNA attachment, whilst the conductive polymer matrix enhances the electron-transfer between DNA and the diamond surface. Fluorescence microscopy and cyclic voltammetry measurements indicate that the polymer-modified BDD has minimal non-specific DNA adsorption, and provides a stable transduction platform for DNA sensing.

Gu, Huiru; Su, Xiaodi; Loh, Kian Ping

2004-04-01

290

Fabrication of cone-shaped boron doped diamond and gold nanoelectrodes for AFM-SECM  

NASA Astrophysics Data System (ADS)

We demonstrate a reliable microfabrication process for a combined atomic force microscopy (AFM) and scanning electrochemical microscopy (SECM) measurement tool. Integrated cone-shaped sensors with boron doped diamond (BDD) or gold (Au) electrodes were fabricated from commercially available AFM probes. The sensor formation process is based on mature semiconductor processing techniques, including focused ion beam (FIB) machining, and highly selective reactive ion etching (RIE). The fabrication approach preserves the geometry of the original AFM tips resulting in well reproducible nanoscaled sensors. The feasibility and functionality of the fully featured tips are demonstrated by cyclic voltammetry, showing good agreement between the measured and calculated currents of the cone-shaped AFM-SECM electrodes.

Avdic, A.; Lugstein, A.; Wu, M.; Gollas, B.; Pobelov, I.; Wandlowski, T.; Leonhardt, K.; Denuault, G.; Bertagnolli, E.

2011-04-01

291

Fabrication of cone-shaped boron doped diamond and gold nanoelectrodes for AFM-SECM.  

PubMed

We demonstrate a reliable microfabrication process for a combined atomic force microscopy (AFM) and scanning electrochemical microscopy (SECM) measurement tool. Integrated cone-shaped sensors with boron doped diamond (BDD) or gold (Au) electrodes were fabricated from commercially available AFM probes. The sensor formation process is based on mature semiconductor processing techniques, including focused ion beam (FIB) machining, and highly selective reactive ion etching (RIE). The fabrication approach preserves the geometry of the original AFM tips resulting in well reproducible nanoscaled sensors. The feasibility and functionality of the fully featured tips are demonstrated by cyclic voltammetry, showing good agreement between the measured and calculated currents of the cone-shaped AFM-SECM electrodes. PMID:21368355

Avdic, A; Lugstein, A; Wu, M; Gollas, B; Pobelov, I; Wandlowski, T; Leonhardt, K; Denuault, G; Bertagnolli, E

2011-04-01

292

Preparation and characterization of vertically columnar boron doped diamond array electrode  

NASA Astrophysics Data System (ADS)

A vertically columnar boron doped diamond (BDD) array electrode was fabricated by microwave plasma chemical vapor deposition. Observed by scanning electron microscopy, the fabricated samples were structured with aligned columns whose diameter and height was 8 ?m and 12 ?m, respectively, and the minimum interval of neighboring columns was 2 ?m. The results of electrochemistry measurement showed that the columnar BDD array electrode possessed high oxygen evolution potential and low background current. Besides that, comparing with flat BDD electrode, the columnar BDD array electrode showed higher electrochemical activity (due to its inner active surface being up to 4.25 cm2), lower impedance of electric double layer, and especially enhanced electrical response signal (2.12 ?A/?M, 4 times of flat BDD in glucose detection as a sample). These excellent performances may open the door for the BDD materials to be applied in wide areas including electrochemical detection, electrochemistry degradation, electrochemical synthesis, and so on.

Zhao, Yang; Yu, Hongtao; Quan, Xie; Chen, Shuo; Zhao, Huimin; Zhang, Yaobin

2014-06-01

293

Synthesis and characterization of aluminum–boron co-doped ZnO nanostructures  

SciTech Connect

Graphical abstract: In this paper, we have reported the development of aluminum boron co-doped ZnO (AZB) nanostructures deposited by sol–gel method using spin coating technique. The structure of AZB nanostructure films has been found to exhibit the hexagonal wurtzite structure. The shape of nanostructures has been changed from seed structure to tetra-pods, tetra-pods to nanorods and finally nanorods to nanofiber with variation in Al concentration. The structural, electrical and optical properties of AZB nanostructures are tuned with shape and size of the nanostructures. The effect of Al concentration on the resistivity (?), carrier concentration (n) and mobility (?) of nanostructure films is shown in graph below. A minimum resistivity of 6.8 × 10{sup ?4} ? cm is obtained in AZB films at doping concentration of B 0.6 at.% and Al 0.4 at.% with a sheet resistance of 24 ?/? and transmittance of ?88% for nanorods structure. These nanostructures could be applicable for a various nano-regime devices such as photovolatics, gas sensing and field emission device. Display Omitted Highlights: ? Synthesis of Al and B co-doped ZnO (AZB) nanostructures. ? Minimum resistivity (?) of 6.8 × 10{sup ?4} ? cm in AZB films. ? Minimum sheet resistance (R{sub s}) 24 ?/? in nanorods (NRs). ? Maximum transmittance ?88% in NRs. ? Application in nano-electronic devices. -- Abstract: In this paper, we have reported the development of aluminum boron co-doped ZnO (AZB) nanostructures deposited by sol–gel method using spin coating technique. The structure of AZB nanostructure films has been found to exhibit the hexagonal wurtzite structure. The shape of AZB nanostructures has changed from seed structure to tetra-pods, tetra-pods to nanorods and finally to nanofibers with increase in aluminum concentration. The structural, electrical and optical properties of AZB films are tuned with shape and size of the nanostructures. These AZB nanostructures could be applicable for various nano-regime devices such as photovoltaic cells, gas sensors and field emission devices.

Kumar, Vinod, E-mail: vinod.phy@gmail.com [Materials Science Group, Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India) [Materials Science Group, Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Department of Physics, Gurukula Kangri University, Haridwar 249404 (India); Singh, R.G. [Department of Electronic Science, Maharaja Agrasen College, University of Delhi 110096 (India)] [Department of Electronic Science, Maharaja Agrasen College, University of Delhi 110096 (India); Singh, Neetu; Kapoor, Avinashi [Department of Electronic Science, University of Delhi South Campus, New Delhi 110021 (India)] [Department of Electronic Science, University of Delhi South Campus, New Delhi 110021 (India); Mehra, R.M. [School of Engineering and Technology, Sharda University, Greater Noida 201306 (India)] [School of Engineering and Technology, Sharda University, Greater Noida 201306 (India); Purohit, L.P. [Department of Physics, Gurukula Kangri University, Haridwar 249404 (India)] [Department of Physics, Gurukula Kangri University, Haridwar 249404 (India)

2013-02-15

294

Synergistic effect on the visible light activity of Ti(3+) doped TiO2 nanorods/boron doped graphene composite.  

PubMed

TiO2/graphene (TiO2-x/GR) composites, which are Ti(3+) self-doped TiO2 nanorods decorated on boron doped graphene sheets, were synthesized via a simple one-step hydrothermal method using low-cost NaBH4 as both a reducing agent and a boron dopant on graphene. The resulting TiO2 nanorods were about 200?nm in length with exposed (100) and (010) facets. The samples were characterized by X-ray diffraction (XRD), UV-visible diffuse reflectance spectroscopy, X-band electron paramagnetic resonance (EPR), X-ray photoelectron spectra (XPS), transmission electron microscope (TEM), Raman, and Fourier-transform infrared spectroscopy (FTIR). The XRD results suggest that the prepared samples have an anatase crystalline structure. All of the composites tested exhibited improved photocatalytic activities as measured by the degradation of methylene blue and phenol under visible light irradiation. This improvement was attributed to the synergistic effect of Ti(3+) self-doping on TiO2 nanorods and boron doping on graphene. PMID:24974890

Xing, Mingyang; Li, Xiao; Zhang, Jinlong

2014-01-01

295

Synergistic effect on the visible light activity of Ti3+ doped TiO2 nanorods/boron doped graphene composite  

PubMed Central

TiO2/graphene (TiO2-x/GR) composites, which are Ti3+ self-doped TiO2 nanorods decorated on boron doped graphene sheets, were synthesized via a simple one-step hydrothermal method using low-cost NaBH4 as both a reducing agent and a boron dopant on graphene. The resulting TiO2 nanorods were about 200?nm in length with exposed (100) and (010) facets. The samples were characterized by X-ray diffraction (XRD), UV-visible diffuse reflectance spectroscopy, X-band electron paramagnetic resonance (EPR), X-ray photoelectron spectra (XPS), transmission electron microscope (TEM), Raman, and Fourier-transform infrared spectroscopy (FTIR). The XRD results suggest that the prepared samples have an anatase crystalline structure. All of the composites tested exhibited improved photocatalytic activities as measured by the degradation of methylene blue and phenol under visible light irradiation. This improvement was attributed to the synergistic effect of Ti3+ self-doping on TiO2 nanorods and boron doping on graphene.

Xing, Mingyang; Li, Xiao; Zhang, Jinlong

2014-01-01

296

Formation and Transport Properties of Defects in Boron-Doped Silicon Studied Through Tight Binding Bond Models.  

NASA Astrophysics Data System (ADS)

The formation and transport properties of point defects in boron-doped silicon have been studied at the atomic level. Robust continuum models of boron diffusion require a knowledge of equilibrium concentrations and diffusivities of self-interstitials, vacancies, boron-defect pairs, and small boron clusters that cannot easily be obtained experimentally. Such thermodynamic and transport properties can, however, be estimated through statistical mechanical and Transition State theories, provided energies and vibrational entropies of point defect formation and migration are known. These energies and entropies have been determined in this work using an empirical quantum mechanical model called Tight Binding (ETB) to describe Si-Si, Si-B, and B-B bonding. Classical models (via the Stillinger-Weber potential) are used to estimate entropies. Defects were identified using "scramble -relaxation" computer runs in which starting positions of atoms were randomly varied and then relaxed to yield stable defect structures. The ETB results for formation energies are generally consistent with LDA ab initio results, to within approximately 0.3eV. C_ {EQ}(I) values determined via the ETB model agree with Au, Pt, and Zn in-diffusion-derived estimates, and contrast with those obtained through modeling of OED and stacking-fault experiments. The negative-U behavior of vacancies and boron interstitials is reproduced by the ETB model, and the correct charge states (0 and -1 for V, and +1 for B_{S }I and B_{i} ) are obtained. Several new di-interstitial clusters, with and without boron, have been obtained which have formation energies 1-2eV/atom lower than isolated interstitials. Although the accuracy limits of the ETB and Stillinger-Weber models make it impossible to determine whether interstitials or vacancies dominate in the mediation of boron transport at equilibrium, it is concluded that, because the migration energy of B_{i} in a direct-interstitial mechanism is very low (0.15eV), boron should have a high effective diffusion coefficient in cases where boron interstitials are super-saturated (e.g., for OED and TED). The ETB model predicts that B _{n} (n from 1 to 4) substitutional clusters decrease in stability with increasing n, but that the inclusion of an interstitial (B_{n}I) makes larger clusters increasingly more stable. This may help explain how boron precipitates nucleate in highly-doped silicon.

Rasband, Paul Brent

297

Solid sampling-graphite furnace atomic absorption spectrometry for the direct determination of boron in plant tissues.  

PubMed

In this work, the potential of graphite furnace atomic absorption spectrometry for the direct determination of B in plant tissues has been investigated. Three certified reference materials (NIST SRM 1570a spinach leaves, NIST SRM 1573a tomato leaves and BCR CRM 679 white cabbage) were selected for this study, the goal always being to develop a fast procedure that could be robust enough to provide a satisfactory performance for all of them, without any modifications in the conditions applied. The use of a suitable chemical modifier was found to be essential for obtaining a reproducible and sufficiently sensitive signal for boron solutions. In this regard, the performance of the combination of citric acid plus W (added as a permanent modifier) was noteworthy, resulting in well-defined signal profiles, a remarkable analyte stabilization during the pyrolysis step (up to 2100 degrees C) and minimal memory effects. This mixture of modifiers provided a good performance for the direct analysis of solid samples as well, but only if a suitable temperature program, favoring the interaction between the analyte and the modifiers, was used. Thus, such a temperature program, with two pyrolysis steps and the addition of NH(4)NO(3) in order to carry out the in situ sample microdigestion, was optimized. Under these conditions, the peak areas obtained for both solid samples and aqueous standards were comparable. Finally, the analysis of the samples was carried out. In all cases, a good agreement with the certified values was obtained, while R.S.D. values ranged between 6 and 10%. It can be concluded that the method proposed shows significant advantages for the determination of this complicated element in solid samples such as the use of aqueous standards for calibration, a high sample throughput (20 min per sample), a suitable limit of detection (0.3 microg g(-1)) and reduced risk of analyte losses and contamination. PMID:17386495

Resano, M; Briceño, J; Aramendía, M; Belarra, M A

2007-01-23

298

Metal-Bosonic Insulator-Superconductor Transition in Boron-Doped Granular Diamond  

NASA Astrophysics Data System (ADS)

In a variety of superconductors, mostly in two-dimensional (2D) and one-dimensional (1D) systems, the resistive superconducting transition R(T) demonstrates in many cases an anomalous narrow R(T) peak just preceding the onset of the superconducting state R=0 at Tc. The amplitude of this R(T) peak in 1D and 2D systems ranges from a few up to several hundred percent. In three-dimensional (3D) systems, however, the R(T) peak close to Tc is rarely observed, and it reaches only a few percent in amplitude. Here we report on the observation of a giant (˜1600%) and very narrow (˜1K) resistance peak preceding the onset of superconductivity in heavily boron-doped diamond. This anomalous R(T) peak in a 3D system is interpreted in the framework of an empirical model based on the metal-bosonic insulator-superconductor transitions induced by a granularity-correlated disorder in heavily doped diamond.

Zhang, Gufei; Zeleznik, Monika; Vanacken, Johan; May, Paul W.; Moshchalkov, Victor V.

2013-02-01

299

TiO 2 nanopowders doped with boron and nitrogen for photocatalytic applications  

NASA Astrophysics Data System (ADS)

TiO 2-based systems have attracted an increasing interest for their potential use as photocatalysts under visible-light irradiation. In this context, the present work was dedicated to the tailored synthesis of TiO 2 nanopowders doped with boron, nitrogen or both species for the photocatalytic degradation of organic dyes. In particular, the systems were synthesized by a sol-gel route starting from titanium(IV) butoxide as a Ti source and thoroughly characterized by the combined use of N 2 physisorption, X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), UV-Vis reflectance spectroscopy and temperature-programmed oxidation (TPO). Finally, the photocatalytic performances in the decomposition of the azo-dye methyl orange (MO) were investigated. The obtained results suggest that both dopants promote the photocatalytic activity with respect to pure TiO 2 systems. Nevertheless, while our surface N-doping does not appreciably modify the titania structure and texture, B incorporation inhibits the TiO 2 crystallite growth and induces an increase in the surface area. As regards the codoped systems, a remarkable reactivity improvement was observed only when B is present in excess with respect to N. A rational interpretation of the observed behaviour was attempted by calculations based on the density functional theory (DFT). We suggest that the presence of B in molar excess with respect to N generates reactive Ti(III) sites, which, in turn, might induce the formation of reactive superoxide species.

Gombac, V.; De Rogatis, L.; Gasparotto, A.; Vicario, G.; Montini, T.; Barreca, D.; Balducci, G.; Fornasiero, P.; Tondello, E.; Graziani, M.

2007-10-01

300

Self- and dopant diffusion in extrinsic boron doped isotopically controlled silicon multilayer structures  

SciTech Connect

Isotopically controlled silicon multilayer structures were used to measure the enhancement of self- and dopant diffusion in extrinsic boron doped silicon. {sup 30}Si was used as a tracer through a multilayer structure of alternating natural Si and enriched {sup 28}Si layers. Low energy, high resolution secondary ion mass spectrometry (SIMS) allowed for simultaneous measurement of self- and dopant diffusion profiles of samples annealed at temperatures between 850 C and 1100 C. A specially designed ion- implanted amorphous Si surface layer was used as a dopant source to suppress excess defects in the multilayer structure, thereby eliminating transient enhanced diffusion (TED) behavior. Self- and dopant diffusion coefficients, diffusion mechanisms, and native defect charge states were determined from computer-aided modeling, based on differential equations describing the diffusion processes. We present a quantitative description of B diffusion enhanced self-diffusion in silicon and conclude that the diffusion of both B and Si is mainly mediated by neutral and singly positively charged self-interstitials under p-type doping. No significant contribution of vacancies to either B or Si diffusion is observed.

Sharp, Ian D.; Bracht, Hartmut A.; Silvestri, Hughes H.; Nicols, Samuel P.; Beeman, Jeffrey W.; Hansen, John L.; Nylandsted Larsen, Arne; Haller, Eugene E.

2002-04-01

301

Forming mechanism of nitrogen doped graphene prepared by thermal solid-state reaction of graphite oxide and urea  

Microsoft Academic Search

Nitrogen doped graphene was synthesized from graphite oxide and urea by thermal solid-state reaction. The samples were characterized by transmission electron microscopy, atomic force microscopy, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectra, element analysis, and electrical conductivity measurement. The results reveal that there is a gradual thermal transformation of nitrogen bonding configurations from amide form nitrogen to

Zhigang Mou; Xiaoye Chen; Yukou Du; Xiaomei Wang; Ping Yang; Suidong Wang

302

Influence of boron concentration on growth characteristic and electro-catalytic performance of boron-doped diamond electrodes prepared by direct current plasma chemical vapor deposition  

NASA Astrophysics Data System (ADS)

A series of boron-doped diamond (BDD) electrodes were prepared by direct current plasma chemical vapor deposition (DC-PCVD) with different compositions of CH 4/H 2/B(OCH 3) 3 gas mixture. A maximum growth rate of 0.65 mg cm -2 h -1 was obtained with CH 4/H 2/B(OCH 3) 3 radio of 4/190/10 and this growth condition was also a turning point for discharge plasma stability which arose from the addition of B(OCH 3) 3 that changed electron energy distribution and influenced the plasma reaction. The surface coating structure and electro-catalytic performance of the BDD electrodes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, Hall test, and electrochemical measurement and electro-catalytic oxidation in phenol solution. It is suggested that the boron doping level and the thermal stress in the films are the main factors affecting the electro-catalytic characteristics of the electrodes. Low boron doping level with CH 4/H 2/B(OCH 3) 3 ratio of 4/199/1 decreased the films electrical conductivity and its electro-catalytic activity. When the carrier concentration in the films reached around 10 20 cm -3 with CH 4/H 2/B(OCH 3) 3 ratio over a range of 4/195/5-4/185/15, the thermal stress in the films was the key reason that influenced the electro-catalytic activity of the electrodes for its effect on diamond lattice expansion. Therefore, the BDD electrode with modest CH 4/H 2/B(OCH 3) 3 ratio of 4/190/10 possessed the best phenol removal efficiency.

Feng, Yujie; Lv, Jiangwei; Liu, Junfeng; Gao, Na; Peng, Hongyan; Chen, Yuqiang

2011-02-01

303

Fano interference of the Raman phonon in heavily boron-doped diamond films grown by chemical vapor deposition  

SciTech Connect

A series of boron-doped polycrystalline diamond films grown by direct current and microwave plasma deposition was studied with Raman and infrared (IR) absorption spectroscopy. A Fano line shape is observed in the Raman spectra for films with a boron concentration in a narrow range near 10[sup 21] cm[sup [minus]3]. The appearance of the Fano line shape is correlated with the disappearance of discrete electronic transitions of the boron acceptor observed in the IR spectrum and the shift of the broadened peak to lower energy. The Fano interaction is attributed to a quantum mechanical interference between the Raman phonon (0.165 eV) and transitions from the broadened impurity band to continuum states composed of excited acceptor and valence band states.

Ager, J.W. III; Walukiewicz, W.; McCluskey, M. (Center for Advanced Materials, Materials Sciences Division, Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States)); Plano, M.A.; Landstrass, M.I. (Crystallume, 3506 Basset St., Santa Clara, California 95054 (United States))

1995-01-30

304

Analysis of laser doping of silicon using different boron dopant sources  

NASA Astrophysics Data System (ADS)

Implementation of selective emitter that decouples the requirements for front doping and metallization leads to improve the efficiency of crystalline silicon solar cells. Formation of such an efficient selective emitter using a laser beam with a suitable wavelength is an attractive method. The present work focuses on the analysis of laser doping of boron using different finite sources such as borosilicate glass (BSG) deposited by PECVD, spin-on solution and BCl3 gas source. KrF excimer laser (248 nm) was used for the selective doping. The surface dopant concentration and depth, as measured using SIMS, were controlled by variation of the laser fluence, pulse number and dopant source thickness. Depending on the type of BSG source, sheet resistance close to 20 ?/sq was achieved at the laser fluences in the range, 2.5-5 J/cm2. The PECVD-BSG layers with a relatively higher thickness resulted in a lower sheet resistance of 20 ?/sq with a junction of depth of ?1 ?m at a moderate laser fluence of 2.5 J/cm2. In the case of BSG deposited by spin-on source, a deeper junction of depth of ?2.7 ?m with a plateau profile of 1 ?m was formed at a laser fluence of 3.1 J/cm2 that resulted in a lower sheet resistance of ?31 ?/sq. Redistribution of the dopant with pulse repetition was observed for the BSG deposited by BCl3 gas source. Pulse repetition at relatively lower laser fluences (>threshold energy) resulted in the best electrical results in combination with a limited laser induced damage in the silicon crystal. Also, multiple laser annealing resulted in redistribution of the dopant profiles in terms of enhanced junction depth.

Prathap, P.; Bartringer, J.; Slaoui, A.

2014-05-01

305

Exploratory study of the new B-doped diamond heater at high pressure and temperature and its application to in situ XRD experiments on hydrous Mg-silicate melt  

Microsoft Academic Search

We demonstrate the successful application of a new heating material, B-doped graphite (boron 10 wt%), to 23 GPa and 2000 °C. The heater resistance increases significantly at temperatures greater than 1200–1400 °C, similar to the diamond transition observed for a pure graphite heater. However, we find that the B-doped graphite furnace can be used at temperatures and pressures higher than that of diamond stability

Akihiro Yamada; Tetsuo Irifune; Hitoshi Sumiya; Yuji Higo; Toru Inoue; Ken-Ichi Funakoshi

2008-01-01

306

Performance of Graphite Pastes Doped with Various Materials as Back Contact for CdS/CdTe Solar Cell  

NASA Astrophysics Data System (ADS)

To date the problem of developing a suitable back contact for CdS/CdTe solar cells has yet to be resolved. The Cu-doped graphite paste that is widely used as a back contact is associated with degradation problems due to possible Cu diffusion across the CdS/CdTe junction. This study was designed to find ways to improve the graphite paste for superior electrical contacts. Mixtures of graphite paste with various material constituents and dopants consisting of silver-, lead-, nickel-, antimony-, bismuth-, or phosphor-based compounds, were studied. Results show that the performances of solar cells fabricated from these graphite pastes vary with the change in the composition. In the cases of Ag2Te and Ni2P, we studied their relationship with the solar cell characteristics with regard to dopant quantity, and furthermore in the case of Ag2Te, with regard to the sintering temperature of the graphite electrode. A fill factor (F.F.) of over 0.65 and efficiencies over 13% were obtained with Ag2Te, Ag3PO4, Ag2MoO4, and NiTe, and efficiencies over 12% were obtained with AgF, AgCl, Ni2P, and Ni3P.

Hanafusa, Akira; Aramoto, Tetsuya; Morita, Akikatsu

2001-12-01

307

Lead detection using micro/nanocrystalline boron-doped diamond by square-wave anodic stripping voltammetry.  

PubMed

Monitoring heavy metal ion levels in water is essential for human health and safety. Electroanalytical techniques have presented important features to detect toxic trace heavy metals in the environment due to their high sensitivity associated with their easy operational procedures. Square-wave voltammetry is a powerful electrochemical technique that may be applied to both electrokinetic and analytical measurements, and the analysis of the characteristic parameters of this technique also enables the mechanism and kinetic evaluation of the electrochemical process under study. In this work, we present a complete optimized study on the heavy metal detection using diamond electrodes. It was analyzed the influence of the morphology characteristics as well as the doping level on micro/nanocrystalline boron-doped diamond films by means of square-wave anodic stripping voltammetry (SWASV) technique. The SWASV parameters were optimized for all films, considering that their kinetic response is dependent on the morphology and/or doping level. The films presented reversible results for the Lead [Pb (II)] system studied. The Pb (II) analysis was performed in ammonium acetate buffer at pH 4.5, varying the lead concentration in the range from 1 to 10?gL(-1). The analytical responses were obtained for the four electrodes. However, the best low limit detection and reproducibility was found for boron doped nanocrystalline diamond electrodes (BDND) doped with 2000mgL(-1) in B/C ratio. PMID:25059140

Arantes, Tatiane M; Sardinha, André; R Baldan, Mauricio; H Cristovan, Fernando; G Ferreira, Neidenei

2014-10-01

308

A theoretical study of silicon-doped boron nitride nanotubes serving as a potential chemical sensor for hydrogen cyanide.  

PubMed

In order to search for a novel sensor to detect and control exposure to hydrogen cyanide (HCN) pollutant molecule in environments, the reactivities of pristine and silicon-doped (Si-doped) (8, 0) single-walled boron nitride nanotubes (BNNTs) towards the HCN molecule are investigated by performing density functional theory (DFT) calculations. The HCN molecule presents strong chemisorption on both the silicon-substituted boron defect site and the silicon-substituted nitrogen defect site of the BNNT, which is in sharp contrast to its weak physisorption on pristine BNNT. A remarkable charge transfer occurs between the HCN molecule and the Si-doped BNNT as proved by the electronic charge densities. The calculated data for the electronic density of states (DOSs) further indicate that the doping of the Si atom improves the electronic transport property of the BNNT, and increases its adsorption sensitivity towards the HCN molecule. Based on calculated results, the Si-doped BNNT is expected to be a potential resource for detecting the presence of toxic HCN. PMID:19923655

Wang, Ruoxi; Zhang, Dongju; Liu, Yongjun; Liu, Chengbu

2009-12-16

309

A theoretical study of silicon-doped boron nitride nanotubes serving as a potential chemical sensor for hydrogen cyanide  

NASA Astrophysics Data System (ADS)

In order to search for a novel sensor to detect and control exposure to hydrogen cyanide (HCN) pollutant molecule in environments, the reactivities of pristine and silicon-doped (Si-doped) (8, 0) single-walled boron nitride nanotubes (BNNTs) towards the HCN molecule are investigated by performing density functional theory (DFT) calculations. The HCN molecule presents strong chemisorption on both the silicon-substituted boron defect site and the silicon-substituted nitrogen defect site of the BNNT, which is in sharp contrast to its weak physisorption on pristine BNNT. A remarkable charge transfer occurs between the HCN molecule and the Si-doped BNNT as proved by the electronic charge densities. The calculated data for the electronic density of states (DOSs) further indicate that the doping of the Si atom improves the electronic transport property of the BNNT, and increases its adsorption sensitivity towards the HCN molecule. Based on calculated results, the Si-doped BNNT is expected to be a potential resource for detecting the presence of toxic HCN.

Wang, Ruoxi; Zhang, Dongju; Liu, Yongjun; Liu, Chengbu

2009-12-01

310

Synthesis and microwave dielectric properties of boron doped SiC powder by sol-gel method  

Microsoft Academic Search

Nano-SiC powders doped by B were synthesized through the carbothermal reduction of xerogels containing the tributyl borate. The results show that the 3C-SiC with minor phase of 6H-SiC is generated at 1 700 ?, and that there are not the characteristic peaks of any boride in the XRD patterns, which indicates that the boron is available only on the crystallization

LI Zhi-min; LUO Fa; ZHU Dong-mei; ZHOU Wan-cheng

311

Electrochemical oxidation of table olive processing wastewater over boron-doped diamond electrodes: Treatment optimization by factorial design  

Microsoft Academic Search

The electrochemical treatment of an effluent from edible olive processing over boron-doped diamond electrodes was investigated. The effect of operating conditions, such as initial organic loading (from 1340 to 5370mg\\/L chemical oxygen demand (COD)), reaction time (from 30 to 120min), current intensity (from 5 to 14A), initial pH (from 3 to 7) and the use of 500mg\\/L H2O2 as an

Anastasios Deligiorgis; Nikolaos P. Xekoukoulotakis; Evan Diamadopoulos; Dionissios Mantzavinos

2008-01-01

312

Electrocatalytic reduction of oxygen to water at Au nanoclusters vacuum-evaporated on boron-doped diamond in acidic solution  

Microsoft Academic Search

Electrocatalytic reduction of oxygen at a boron (B)-doped diamond (BDD) electrode on which Au nanoclusters (GNCs) were deposited by vacuum-evaporation was investigated in 50 mM H2SO4 solution. Oxygen reduction current started to flow at a more positive potential at the GNCs\\/BDD electrode than at a polycrystalline gold electrode. Formation of water through a 4-electron reduction pathway at the GNCs\\/BDD electrode

Ichizo Yagi; Tomotaka Ishida; Kohei Uosaki

2004-01-01

313

Electrochemical incineration of chloromethylphenoxy herbicides in acid medium by anodic oxidation with boron-doped diamond electrode  

Microsoft Academic Search

The electrochemical degradation of saturated solutions of herbicides 4-chloro-2-methylphenoxyacetic acid, 2-(4-chlorophenoxy)-2-methylpropionic acid and 2-(4-chloro-2-methylphenoxy)propionic acid in 1M HClO4 on a boron-doped diamond (BDD) thin film anode has been studied by chronoamperometry, cyclic voltammetry and bulk electrolysis. At low anodic potentials polymeric products are formed causing the fouling and deactivation of BDD. This is reactivated at high potentials when water decomposes

Birame Boye; Enric Brillas; Beatrice Marselli; Pierre-Alain Michaud; Christos Comninellis; Giuseppe Farnia; Giancarlo Sandonà

2006-01-01

314

Electrochemical incineration of cresols: A comparative study between PbO 2 and boron-doped diamond anodes  

Microsoft Academic Search

The electrooxidation of aqueous solutions containing 5mM of o-, m- and p-cresol at pH 4.0 has been investigated using a flow filter-press reactor with a boron-doped diamond (BDD) under galvanostatic electrolysis. All cresols are degraded at similar rate up to attaining overall mineralization. Comparable treatment of the m-cresol effluent on PbO2 leads to partial electrochemical incineration. However, this pollutant is

Cristina Flox; Conchita Arias; Enric Brillas; André Savall; Karine Groenen-Serrano

2009-01-01

315

Electrochemical analysis of d-penicillamine using a boron-doped diamond thin film electrode applied to flow injection system  

Microsoft Academic Search

The electroanalysis of d-penicillamine in 0.1 phosphate buffer (pH 7) was studied at a boron-doped diamond thin film (BDD) electrode using cyclic voltammetry as a function of concentration of analyte and pH of analyte solution. Comparison experiments were performing using a glassy carbon (GC) electrode. The BDD electrode exhibited a well-resolved and irreversible oxidation voltammogram, but the GC electrode provided

Nattakarn Wangfuengkanagul; Orawon Chailapakul

2002-01-01

316

Applicability of boron-doped diamond electrode to the degradation of chloride-mediated and chloride-free wastewaters  

Microsoft Academic Search

The electrochemical degradation of chloride-mediated and chloride-free dye wastewaters was investigated on a boron-doped diamond (BDD) electrode in comparison with that on a dimensionally stable anode (DSA), and the applicability of BDD electrode to the degradation of these two kinds of wastewaters was explored. In chloride-free wastewater, the electrochemical degradation efficiency of dye on BDD electrode was much higher than

Meifen Wu; Guohua Zhao; Mingfang Li; Lei Liu; Dongming Li

2009-01-01

317

On the changing electrochemical behaviour of boron-doped diamond surfaces with time after cathodic pre-treatments  

Microsoft Academic Search

The electrochemical response of the Fe(CN)64?\\/3? redox couple on boron-doped diamond (BDD) electrodes immediately after a cathodic pre-treatment and as a function of time exposed to atmospheric conditions is reported here. After this pre-treatment the electrode exhibits a changing electrochemical behaviour, i.e., a loss of the reversibility for the Fe(CN)64?\\/3? redox couple as a function of time. Raman spectra showed

Giancarlo R. Salazar-Banda; Leonardo S. Andrade; Pedro A. P. Nascente; Paulo S. Pizani; Romeu C. Rocha-Filho; Luis A. Avaca

2006-01-01

318

Product and by-product formation in laboratory studies on disinfection electrolysis of water using boron-doped diamond anodes  

Microsoft Academic Search

Boron-doped diamond (BDD) electrodes were studied with respect to the formation of inorganic by-products in water electrolysis. Experiments in non-divided cells were performed with systems containing sulphate, chloride, chlorite, chlorate and nitrate ions. Discontinuous experiments in thermostated cells with rotating disk diamond anodes and expanded mesh IrO2 cathodes were carried out at 20°C. Current density was varied between 50 and

M. E. Henry Bergmann; Johanna Rollin

2007-01-01

319

Electrochemical degradation of 17?-estradiol (E2) at boron-doped diamond (Si\\/BDD) thin film electrode  

Microsoft Academic Search

Electrochemical degradation of aqueous solutions containing 17?-estradiol (E2), concentrations range of 250–750?gdm?3, has been extensively studied using boron-doped diamond (BDD) anode with a working solution volume of 250ml under galvanostatic control. Cyclic voltammetric experiments were performed to examine the redox response of E2 as a function of cycle number. The effect of operating variables such as initial concentration of E2,

M. Murugananthan; S. Yoshihara; T. Rakuma; N. Uehara; T. Shirakashi

2007-01-01

320

Electrochemical determination of captopril at boron-doped diamond thin film electrode applied to a flow injection system  

Microsoft Academic Search

A boron-doped diamond thin film (BDD) electrode was first used to study the electroanalysis of captopril in phosphate buffer (pH=9) by several techniques such as cyclic voltammetry, hydrodynamic voltammetry and flow injection with amperometric detection. Cyclic voltammetry was used to study the reaction as a function of concentration of analyte. The results were compared with a glassy carbon (GC) electrode

W. Siangproh; P. Ngamukot; O. Chailapakul

2003-01-01

321

Shallow donors with high n-type electrical conductivity in homoepitaxial deuterated boron-doped diamond layers  

Microsoft Academic Search

Diamond is a unique semiconductor for the fabrication of electronic and opto-electronic devices because of its exceptional physical and chemical properties. However, a serious obstacle to the realization of diamond-based devices is the lack of n-type diamond with satisfactory electrical properties. Here we show that high-conductivity n-type diamond can be achieved by deuteration of particularly selected homo-epitaxially grown (100) boron-doped

Zéphirin Teukam; Jacques Chevallier; Cécile Saguy; Rafi Kalish; Dominique Ballutaud; Michel Barbé; François Jomard; Annie Tromson-Carli; Catherine Cytermann; James E. Butler; Mathieu Bernard; Céline Baron; Alain Deneuville

2003-01-01

322

Development of an amperometric biosensor based on covalent immobilization of tyrosinase on a boron-doped diamond electrode  

Microsoft Academic Search

An amperometric enzyme electrode based on direct covalent immobilization of tyrosinase on a boron-doped diamond (BDD) electrode has been developed for the detection of phenolic compounds. Combined chemical and electrochemical modifications of the BDD film with 4-nitrobenzenediazonium tetrafluoroborate, an aminophenyl-modified BDD (AP–BDD) surface was produced, and then the tyrosinase was covalently immobilized on the BDD surface via carbodiimide coupling. The

YanLi Zhou; JinFang Zhi

2006-01-01

323

Simultaneous square-wave voltammetric determination of aspartame and cyclamate using a boron-doped diamond electrode  

Microsoft Academic Search

A simple and highly selective electrochemical method was developed for the simultaneous determination of aspartame and cyclamate in dietary products at a boron-doped diamond (BDD) electrode. In square-wave voltammetric (SWV) measurements, the BDD electrode was able to separate the oxidation peak potentials of aspartame and cyclamate present in binary mixtures by about 400mV. The detection limit for aspartame in the

Roberta Antigo Medeiros; Adriana Evaristo de Carvalho; Romeu C. Rocha-Filho; Orlando Fatibello-Filho

2008-01-01

324

Microchip capillary electrophoresis with a boron-doped diamond electrode for rapid separation and detection of purines  

Microsoft Academic Search

Microchip capillary electrophoresis (CE) coupled with a boron-doped diamond (BDD) electrode has been employed for the separation and detection of several purines and purine-containing compounds. The BDD end-channel amperometric detector offers favorable signal-to-noise (S\\/N) characteristics at the high detection potential (+1.3V) essential for detecting purine-related compounds. Factors influencing the separation and detection processes were examined and optimized. Five purines (guanine,

Joseph Wang; Gang Chen; Alexander Muck; Dongchan Shin; Akira Fujishima

2004-01-01

325

Kinetics and mechanism of the deep electrochemical oxidation of sodium diclofenac on a boron-doped diamond electrode  

NASA Astrophysics Data System (ADS)

The kinetics and mechanism of the deep oxidation of sodium diclofenac on a boron-doped diamond electrode are studied to develop a technique for purifying wastewater from pharmaceutical products. The products of sodium diclofenac electrolysis are analyzed using cyclic voltammetry and nuclear magnetic resonance techniques. It is shown that the toxicity of the drug and products of its electrolysis decreases upon its deep oxidation.

Vedenyapina, M. D.; Borisova, D. A.; Rosenwinkel, K.-H.; Weichgrebe, D.; Stopp, P.; Vedenyapin, A. A.

2013-08-01

326

Highly graphitized nitrogen-doped porous carbon nanopolyhedra derived from ZIF-8 nanocrystals as efficient electrocatalysts for oxygen reduction reactions  

NASA Astrophysics Data System (ADS)

Nitrogen-doped graphitic porous carbons (NGPCs) have been synthesized by using a zeolite-type nanoscale metal-organic framework (NMOF) as a self-sacrificing template, which simultaneously acts as both the carbon and nitrogen sources in a facile carbonization process. The NGPCs not only retain the nanopolyhedral morphology of the parent NMOF, but also possess rich nitrogen, high surface area and hierarchical porosity with well-conducting networks. The promising potential of NGPCs as metal-free electrocatalysts for oxygen reduction reactions (ORR) in fuel cells is demonstrated. Compared with commercial Pt/C, the optimized NGPC-1000-10 (carbonized at 1000 °C for 10 h) catalyst exhibits comparable electrocatalytic activity via an efficient four-electron-dominant ORR process coupled with superior methanol tolerance as well as cycling stability in alkaline media. Furthermore, the controlled experiments reveal that the optimum activity of NGPC-1000-10 can be attributed to the synergetic contributions of the abundant active sites with high graphitic-N portion, high surface area and porosity, and the high degree of graphitization. Our findings suggest that solely MOF-derived heteroatom-doped carbon materials can be a promising alternative for Pt-based catalysts in fuel cells.Nitrogen-doped graphitic porous carbons (NGPCs) have been synthesized by using a zeolite-type nanoscale metal-organic framework (NMOF) as a self-sacrificing template, which simultaneously acts as both the carbon and nitrogen sources in a facile carbonization process. The NGPCs not only retain the nanopolyhedral morphology of the parent NMOF, but also possess rich nitrogen, high surface area and hierarchical porosity with well-conducting networks. The promising potential of NGPCs as metal-free electrocatalysts for oxygen reduction reactions (ORR) in fuel cells is demonstrated. Compared with commercial Pt/C, the optimized NGPC-1000-10 (carbonized at 1000 °C for 10 h) catalyst exhibits comparable electrocatalytic activity via an efficient four-electron-dominant ORR process coupled with superior methanol tolerance as well as cycling stability in alkaline media. Furthermore, the controlled experiments reveal that the optimum activity of NGPC-1000-10 can be attributed to the synergetic contributions of the abundant active sites with high graphitic-N portion, high surface area and porosity, and the high degree of graphitization. Our findings suggest that solely MOF-derived heteroatom-doped carbon materials can be a promising alternative for Pt-based catalysts in fuel cells. Electronic supplementary information (ESI) available: Additional SEM and TEM images, EDS, crystal structures illustration, XRD, Raman, N2 sorption, XPS, FTIR, TGA and supplementary reaction tests. See DOI: 10.1039/c4nr00348a

Zhang, Linjie; Su, Zixue; Jiang, Feilong; Yang, Lingling; Qian, Jinjie; Zhou, Youfu; Li, Wenmu; Hong, Maochun

2014-05-01

327

Preparation of boron-doped porous titania networks containing gold nanoparticles with enhanced visible-light photocatalytic activity.  

PubMed

The ability to decrease the electron/hole recombination rate, and decrease the band gap of titania to allow photoactivity on irradiation with visible light is attracting more and more attention. Here, boron doping of the titania, the deposition of gold nanoparticles, along with a meso-macroporous structure were obtained using a facile agarose gel templating process combined with sol-gel chemistry. The Au/B/TiO(2) nanocomposites were characterized using SEM, TEM, XRD, N(2) gas sorption, diffuse UV-vis, photoluminescence, and SIMS. The photocatalytic activity was assessed by degradation of an organic probe molecule (methylene blue) under visible light (? > 420 nm). The resulting materials achieved photocatalytic activities up to 50% greater than the commercial Degussa P25 under visible light. The enhancement in photocatalytic activity was primarily attributed to the decrease in band gap as a result of the boron doping and its influence on the anatase to rutile phase formation: The doped materials were highly crystalline and an optimum anatase to rutile ratio (3:1) was obtained with 0.25 wt % boron in the sample calcined at 650 °C. In addition, the presence of the gold nanoparticles decreased recombination between the photoexcited electrons and holes, which further improved the photocatalytic activity. PMID:22242543

Wang, Xingdong; Blackford, Mark; Prince, Kathryn; Caruso, Rachel A

2012-01-01

328

Low friction stainless steel coatings graphite doped elaborated by air plasma sprayed  

Microsoft Academic Search

A new process has been developed to incorporate graphite particles into a stainless steel coating during its formation. Four\\u000a means have been tested to inject the graphite particles outside the plasma jet and its plume: graphite suspension, a graphite\\u000a rod rubbed on the rotating sample, powder injection close to the substrate with an injector, or a specially designed guide.\\u000a The

A. Harir; H. Ageorges; A. Grimaud; P. Fauchais; F. Platon

2004-01-01

329

Low temperature boron and phosphorous doped SiGe for recessed and raised sources and drains  

NASA Astrophysics Data System (ADS)

We have first of all studied the growth kinetics of boron and phosphorous doped, 20-30 nm thick Si 0.65Ge 0.35 layers, the aim being their integration in recessed and raised sources and drains. Those layers have been grown at low pressure (20 Torr) and low temperature (650 °C) with a heavily chlorinated chemistry (in order to be selective versus SiO 2 (isolation) and Si 3N 4 (sidewall spacers)). We have quantified the impact of the diborane and phosphine flow on (i) the SiGe crystalline quality and strain state, (ii) the amount of boron or phosphorous atoms incorporated in it and (iii) the SiGe:B or SiGe:P growth kinetics. As the diborane flow increases, the SiGe:B growth rate definitely increases, while the real Ge concentration (from Time-Of-Flight Secondary Ions Mass Spectrometry) is more or less steady. B atoms, being much smaller than Si or Ge, partially compensate the compressive strain in the SiGe:B layers, leading to a decrease in the apparent Ge concentration (from X-ray diffraction). Opposite trends are observed for SiGe:P. There is indeed a definite decrease in the SiGe:P growth rate together with a definite increase in both the apparent and real Ge concentration as the phosphine flow increases. The Boron atomic concentration increases linearly with the diborane flow, with however a practical limit around 3.5×10 20 cm -3 in order to stay monocrystalline. Meanwhile, the phosphorous atomic concentration saturates quite rapidly at values close to 8-9×10 19 cm -3 as the phosphine flow increases (most likely due to surface segregation). In the second part we have highlighted some of the difficulties encountered when trying to selectively grow intrinsic SiGe raised S/Ds at 650 °C on patterned, extra-thin Silicon-On-Insulator wafers and some of the solutions identified in order to obtain 2D thick films. Amongst those, we can mention the 750 °C deposition of a thin Si buffer or the in-situ high HCl partial pressure etch at 650 °C of a few nm of Si prior to SiGe Selective Epitaxial Growth (SEG), the drastic reduction of the incoming HCl flow during SiGe SEG, etc.

Hartmann, J. M.; Py, M.; Barnes, J. P.; Prévitali, B.; Batude, P.; Billon, T.

2011-07-01

330

Effect of surface defects by RF oxygen plasma on the electrical properties of thin boron-doped diamond layers in electrolyte  

Microsoft Academic Search

The effect of surface defects induced by RF oxygen plasma treatment on the electrical properties of thin boron-doped epitaxial diamond layers was investigated by electrochemical analysis in the modes of electrochemical electrode and ion sensitive field-effect transistor (ISFET). The doping profile employed allowed almost full depletion in the electrolyte used within the potential window of water electrolysis. The high near

J. Scharpf; A. Denisenko; C. Pietzka; E. Kohn

2011-01-01

331

Recent Developments in Pyrolytic Graphite.  

National Technical Information Service (NTIS)

A study of the fine microstructure of boronated pyrolytic graphite was made utilizing optical and electron microscopy and X-ray diffraction techniques. The influence of boron content on the laminar structure, the lattice parameter, the lattice strain, the...

C. P. Gazzara R. N. Katz

1969-01-01

332

High energy-resolution electron energy-loss spectroscopy study of the electronic structures of Li- and Mg-doped alpha-rhombohedral boron.  

PubMed

Electron-doped alpha-rhombohedral boron (alpha-r-B) crystals were synthesized by Li- and Mg-dopings. The doped alpha-r-B particles showed a shiny metallic colour, though non-doped alpha-r-B crystals showed a dark red colour (red boron). The electronic structures of doped alpha-r-B single crystals were examined by a high energy-resolution electron energy-loss spectroscopy microscope. Boron 1s electron-excitation spectra, which show the density of states of the conduction bands, of Li-doped alpha-r-B showed a chemical shift toward a smaller binding-energy side, indicating a charge transfer from the doped atoms to alpha-r-B. These spectra also showed a sharp intensity increase at the onset with a width of an energy resolution of the experiment. The sharp intensity increase may be assigned to a Fermi edge produced by the electron doping. The spectra of Mg-doped alpha-r-B showed a chemical shift indicating an electron doping, but did not show the presence of a Fermi edge. PMID:15582971

Terauchi, Masami; Oguri, Atsushi; Kimura, Kaoru; Fujiwara, Akihiko

2004-01-01

333

Highly graphitized nitrogen-doped porous carbon nanopolyhedra derived from ZIF-8 nanocrystals as efficient electrocatalysts for oxygen reduction reactions.  

PubMed

Nitrogen-doped graphitic porous carbons (NGPCs) have been synthesized by using a zeolite-type nanoscale metal-organic framework (NMOF) as a self-sacrificing template, which simultaneously acts as both the carbon and nitrogen sources in a facile carbonization process. The NGPCs not only retain the nanopolyhedral morphology of the parent NMOF, but also possess rich nitrogen, high surface area and hierarchical porosity with well-conducting networks. The promising potential of NGPCs as metal-free electrocatalysts for oxygen reduction reactions (ORR) in fuel cells is demonstrated. Compared with commercial Pt/C, the optimized NGPC-1000-10 (carbonized at 1000 °C for 10 h) catalyst exhibits comparable electrocatalytic activity via an efficient four-electron-dominant ORR process coupled with superior methanol tolerance as well as cycling stability in alkaline media. Furthermore, the controlled experiments reveal that the optimum activity of NGPC-1000-10 can be attributed to the synergetic contributions of the abundant active sites with high graphitic-N portion, high surface area and porosity, and the high degree of graphitization. Our findings suggest that solely MOF-derived heteroatom-doped carbon materials can be a promising alternative for Pt-based catalysts in fuel cells. PMID:24806824

Zhang, Linjie; Su, Zixue; Jiang, Feilong; Yang, Lingling; Qian, Jinjie; Zhou, Youfu; Li, Wenmu; Hong, Maochun

2014-06-21

334

Determination of trace impurities in boron nitride by graphite furnace atomic absorption spectrometry and electrothermal vaporization inductively coupled plasma optical emission spectrometry using solid sampling  

NASA Astrophysics Data System (ADS)

Two digestion-free methods for trace analysis of boron nitride based on graphite furnace atomic absorption spectrometry (GFAAS) and electrothermal vaporization inductively coupled plasma spectrometry optical emission (ETV-ICP-OES) using direct solid sampling have been developed and applied to the determination of Al, Ca, Cr, Cu, Fe, Mg, Mn, Si, Ti and Zr in four boron nitride materials in concentration intervals of 1-23, 54-735, 0.05-21, 0.005-1.3, 1.6-112, 4.5-20, 0.03-1.8, 6-46, 38-170 and 0.4-2.3 ?g g - 1 , respectively. At optimized experimental conditions, with both methods, effective in-situ analyte/matrix separation was achieved and calibration could be performed using calibration curves measured with aqueous standard solutions. In solid sampling GFAAS, before sampling, the platform was covered with graphite powder and, for determination of Si, also the Pd/Mg(NO 3) 2 modifier was used. In the determination of all analyte elements by solid sampling ETV-ICP-OES, Freon R12 was added to argon carrier gas. For solid sampling GFAAS and ETV-ICP-OES, the achievable limits of detection were within 5 (Cu)-130 (Si) ng g - 1 and 8 (Cu)-200 (Si) ng g - 1 , respectively. The results obtained by these two methods for four boron nitride materials of different purity grades are compared each with the other and with those obtained in analysis of digests by ICP-OES. The performance of the two solid sampling methods is compared and discussed.

Barth, P.; Hassler, J.; Kudrik, I.; Krivan, V.

2007-09-01

335

Electrochemical oxidation of hydroquinone, resorcinol, and catechol on boron-doped diamond anodes.  

PubMed

The electrochemical oxidation of aqueous wastes polluted with hydroquinone, resorcinol, or catechol on boron-doped diamond electrodes has been studied. The complete mineralization of the organic waste has been obtained independently of the nature of each isomer. No aromatic intermediates were found during the treatment, and solely aliphatic intermediates (carboxylic acids C4 and C2, mainly) were detected in the three cases. Although as from the bulk electrolyses study no differences in the electrochemical oxidation of dihydroxybenzenes seem to exist, different voltammetric behavior between resorcinol and the other two isomers was obtained in the voltammetric study. Catechol and hydroquinone have a reversible quinonic form, and a cathodic reduction peak appears in their voltammograms. The characterization of the first steps in the electrochemical oxidation of the three dihydroxybenzenes showed the formation of a larger number of intermediates in the oxidation of catechol, although no carbon dioxide was detected in its oxidation. Conversely, the oxidation of resorcinol and hydroquinone lead to the formation of important concentrations of carbon dioxide. The nondetection of aromatic intermediates, even if small quantities of charge are passed, confirms that the oxidation must be carried out directly on the electrode surface or by hydroxyl radicals generated by decomposition of water. PMID:16201653

Nasr, Bensalah; Abdellatif, Gadri; Cañizares, Pablo; Sáez, Cristina; Lobato, Justo; Rodrigo, Manuel A

2005-09-15

336

Functionalization of boron-doped nanocrystalline diamond with n3 dye molecules.  

PubMed

N3 dye molecules [cis-bis(isothiocyanato)bis(2,2'-bipyridyl-4,4'-dicarboxylato)ruthenium(II)] are covalently attached to boron-doped nanocrystalline diamond (B:NCD) thin films through a combination of coupling chemistries, i.e., diazonium, Suzuki, and EDC-NHS. X-ray and ultraviolet photoelectron spectroscopy and near-edge X-ray absorption fine structure spectroscopy are used to verify the covalent bonding of the dye on the B:NCD surface (compared to a hydrogen-terminated reference). The spectroscopic results confirm the presence of a dense N3 chromophore layer, and the positions of the frontier orbitals of the dye relative to the band edge of the B:NCD thin film are inferred as well. Proof-of-concept photoelectrochemical measurements show a strong increase in the photocurrent compared to non-dye-functionalized B:NCD films. This study opens up the possibility of applying N3-sensitized B:NCD thin films as hole conductors in dye-sensitized solar cells. PMID:24915549

Yeap, W S; Liu, X; Bevk, D; Pasquarelli, A; Lutsen, L; Fahlman, M; Maes, W; Haenen, K

2014-07-01

337

Simultaneous Chronoamperometric Sensing of Ascorbic Acid and Acetaminophen at a Boron-Doped Diamond Electrode  

PubMed Central

Cyclic voltammetry (CV) and chronoamperometry (CA) have been used to sense and determine simultaneously L-ascorbic acid (AA) and acetaminophen (AC) at a boron-doped diamond electrode (BDDE) in a Britton-Robinson buffer solution. The calibration plots of anodic current peak versus concentration obtained from CV and CA data for both investigated compounds in single and di-component solutions over the concentration range 0.01 mM – 0.1 mM proved to be linear, with very good correlation parameters. Sensitivity values and RSD of 2-3% were obtained for various situations, involving both individual and simultaneous presence of AA and AC. The chronoamperometric technique associated with standard addition in sequential one step and/or two successive and continuous chronoamperograms at two characteristic potential levels represented a feasible option for the simultaneous determination of AA and AC in real sample systems such as pharmaceutical formulations. The average values indicated by the supplier were confirmed to a very close approximation from chronoamperomgrams by using several additions with the application of suitable current correction factors.

Cofan, Codruta; Radovan, Ciprian

2008-01-01

338

Boron-doped diamond nano/microelectrodes for biosensing and in vitro measurements.  

PubMed

Since the fabrication of the first diamond electrode in the mid 1980s, repid progress has been made on the development and application of this new type of electrode material. Boron-doped diamond (BDD) electrodes exhibit outstanding properties compared to oxygen-containing sp2 carbon electrodes. These properties make BDD electrodes an ideal choice for use in complex samples. In recent years, BDD microelectrodes have been applied to in vitro measurements of biological molecules in tissues and cells. This review will summarize recent progress in the development and applications of BDD electrodes in bio-sensing and in vitro measurements of biomolecules. In the first section, the methods for BDD diamond film deposition and BDD microelectrodes preparation are described. This is followed by a description and discussion of several approaches for characterization of the BDD electrode surface structure, morphology, and electrochemical activity. Further, application of BDD microelectrodes for use in the in vitro analysis of norepinephrine (NE), serotonin (5-HT), nitric oxide (NO), histamine, and adenosine from tissues are summarized and finally some of the remaining challenges are discussed. PMID:21196394

Dong, Hua; Wang, Shihua; Galligan, James J; Swain, Greg M

2011-01-01

339

Use of seawater for the boron-doped diamond electrochemical treatment of diluted vinasse wastewater.  

PubMed

Vinasse wastewater of high organic content (COD = 131,000 mg/L) and low biodegradability (BOD5/COD = 0.11) cannot be easily managed and usually require several consecutive treatment steps. The objective of this work was to dilute vinasse wastewater with seawater and then subject them to electrochemical oxidation over boron-doped diamond (BDD) electrodes. The use of seawater is a rational and novel approach for plants close to the seashore since it may achieve the desirable levels of effluent concentration and conductivity without consuming other water resources and extra electrolytes. Experiments were conducted at initial COD values of 830-8,400 mg/L, NaCl concentrations of 34-200 mM and current densities of 70-200 mA/cm(2) for up to 5 hours. The effect of current density and NaCl concentration was marginal on the electrochemical treatment, while the single most important parameter was the initial COD concentration. The order of reaction for COD reduction appears to be 'first' at low effluent concentrations and it decreases to 'zero' at higher concentrations, denoting the importance of the ratio of organics to reactive radicals concentration. Based on COD and total organic carbon data, it is postulated that degradation occurs predominantly through total oxidation (i.e. mineralization) to carbon dioxide and water, which is characteristic of BDD anodes. PMID:24334881

Daskalaki, V M; Marakas, H; Mantzavinos, D; Katsaounis, A; Gikas, P

2013-01-01

340

Comparison of electrocatalytic characterization of boron-doped diamond and SnO2 electrodes  

NASA Astrophysics Data System (ADS)

Boron-doped diamond (BDD) and SnO2 electrodes were prepared by direct current plasma chemical vapor deposition (DC-PCVD) and sol-gel method, respectively. Electrochemical characterization of the two electrodes were investigated by phenol electrochemical degradation, accelerated service life test, cyclic voltammetry (CV) in phenol solution, polarization curves in H2SO4. The surface morphology and crystal structure of two electrodes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. The results showed a considerable difference between the two electrodes in their electrocatalytic activity, electrochemical stability and surface properties. Phenol was readily mineralized to CO2 at BDD electrode, favoring electrochemical combustion, but its degradation was much slower at SnO2 electrode. The service life of BDD electrode was 10 times longer than that of SnO2. Higher electrocatalytic activity and electrochemical stability of BDD electrode arise from its high oxygen evolution potential and the physically absorbed hydroxyl radicals (OH) on electrode surface.

Lv, Jiangwei; Feng, Yujie; Liu, Junfeng; Qu, Youpeng; Cui, Fuyi

2013-10-01

341

TDAB-induced DNA plasmid condensation on the surface of a reconstructed boron doped silicon substrate  

NASA Astrophysics Data System (ADS)

Our study aims at a better control and understanding of the transfer of a complex [DNA supercoiled plasmid - dodecyltrimethylammonium surfactant] layer from a liquid-vapour water interface onto a silicon surface without any additional cross-linker. The production of the complexed layer and its transfer from the aqueous subphase to the substrate is achieved with a Langmuir-Blodgett device. The substrate consists of a reconstructed boron doped silicon substrate with a nanometer-scale roughness. Using X-ray photoelectron spectroscopy and atomic force microscopy measurements, it is shown that the DNA complexes are stretched in a disorderly manner throughout a 2-4 nm high net-like structure. This architecture is composed of tilted cationic surfactant molecules bound electrostatically to DNA, which exhibits a characteristic network arrangement with a measured average fiber diameter of about 45 ± 15 nm covering the entire surface. The mechanism of transfer of this layer onto the planar surface of the semi-conductor and the parameters of the process are analysed and illustrated by atomic force microscopy snapshots. The molecular layer exhibits the typical characteristics of a spinodal decomposition pattern or dewetting features. Plasmid molecules appear like long flattened fibers covering the surface, forming holes of various shapes and areas. The cluster-cluster aggregation of the complex structure gets very much denser on the substrate edge. The supercoiled DNA plasmids undergo conformational changes and a high degree of condensation and aggregation is observed. Perspectives and potential applications are considered.

Mougin, Antoine; Babak, Valéry G.; Palmino, Frank; Bêche, Eric; Baros, Francis; Hunting, Darel J.; Sanche, Léon; Fromm, Michel

342

Development of electrolyte-free ozone sensors using boron-doped diamond electrodes.  

PubMed

The electrochemical detection of dissolved ozone in water was examined using boron-doped diamond (BDD) electrodes. A well-defined reduction peak was observed at ~380 mV for H-terminated BDD, whereas it was observed at ~200 mV in the case of O-terminated BDD for an ozone solution in a 0.1 M phosphate buffer solution at pH 7. The peak potential for ozone reduction was selective with respect to oxygen reduction at both H- and O-terminated BDD electrodes, whereas it occurred at approximately the same potential as oxygen reduction at other types of solid electrodes, including glassy-carbon, platinum, and gold electrodes. Interference from chlorine was not observed in lower concentration than 300 ?M ClO(-). Furthermore, in order to apply the detection technique to electrolyte-free media, BDD microelectrodes were also used. A linear calibration curve for dissolved ozone in water could be achieved between concentrations of 0.49 and 740 ?M, with an estimated detection limit (S/N = 3) of 0.185 ?M (S/N = 3). Excellent stability was demonstrated for repetitions of these calibration curves performed in 3 consecutive days. PMID:23544430

Ishii, Yuya; Ivandini, Tribidasari A; Murata, Kazutaka; Einaga, Yasuaki

2013-05-01

343

Electro-oxidation of two reactive azo dyes on boron-doped diamond electrode.  

PubMed

Electrochemical oxidation (decolorization/degradation) of blue and red commercial reactive azo dyes was carried out on boron-doped diamond (BDD) electrode. The effect of various quantities of FeSO(4) was investigated in the electro-Fenton reaction on BDD. Progress of dyes degradation during the electrolysis and electro-Fenton reaction was monitored by UV-visible absorption and by estimation of the chemical oxygen demand (COD). Direct electrolysis showed a limiting capacity for red and blue dye removal even at high current densities, e.g. maximum red color and COD removal were 70 and 20%, respectively at 30 mA cm(-2) after 300 min. Higher red and blue color removal efficiencies were achieved by electro-Fenton oxidation. Current density of 30 mA cm(-2) in the presence of 0.05 mmol/L of FeSO(4) resulted in the red color and COD removal of 98 and 96%, respectively. The optimum FeSO(4) concentration for the electro-Fenton reaction was determined to be 0.05 mmol/L. Instantaneous current efficiency (ICE) in the presence of FeSO(4) was almost three times higher than for experiments carried out without FeSO(4). PMID:22744674

Almomani, Fares; Baranova, Elena A

2012-01-01

344

Rapid-thermal-processing-based internal gettering for heavily boron-doped Czochralski silicon  

NASA Astrophysics Data System (ADS)

The effect of rapid-thermal processing (RTP) ambients on the formation of oxygen precipitates and denuded zone (DZ) in heavily boron-doped (HB) Czochralski (Cz) silicon by a low-high (L-H) two-step annealing (800 °C/4 h+1000 °C/16 h) has been investigated. It was found that after the L-H two-step annealing, there was a high density of bulk microdefects (BMDs) and no observable DZ was formed near the surface in HB Cz silicon wafers preannealed by the RTP in Ar ambient, while the BMD density was quite low in HB Cz silicon wafers preannealed by the RTP in O2 ambient. However, applying the preannealing of RTP sequentially in Ar and O2 ambients allowed us to obtain a high density of BMDs in combination with a sufficient DZ by the subsequent L-H two-step annealing. This approach offers a pathway to optimize internal gettering for HB Cz silicon.

Fu, Liming; Yang, Deren; Ma, Xiangyang; Tian, Daxi; Que, Duanlin

2006-11-01

345

Development of a biochemical oxygen demand sensor using gold-modified boron doped diamond electrodes.  

PubMed

Gold-modified boron doped diamond (BDD) electrodes were examined for the amperometric detection of oxygen as well as a detector for measuring biochemical oxygen demand (BOD) using Rhodotorula mucilaginosa UICC Y-181. An optimum potential of -0.5 V (vs Ag/AgCl) was applied, and the optimum waiting time was observed to be 20 min. A linear calibration curve for oxygen reduction was achieved with a sensitivity of 1.4 ?A mg(-1) L oxygen. Furthermore, a linear calibration curve in the glucose concentration range of 0.1-0.5 mM (equivalent to 10-50 mg L(-1) BOD) was obtained with an estimated detection limit of 4 mg L(-1) BOD. Excellent reproducibility of the BOD sensor was shown with an RSD of 0.9%. Moreover, the BOD sensor showed good tolerance against the presence of copper ions up to a maximum concentration of 0.80 ?M (equivalent to 50 ppb). The sensor was applied to BOD measurements of the water from a lake at the University of Indonesia in Jakarta, Indonesia, with results comparable to those made using a standard method for BOD measurement. PMID:23088708

Ivandini, Tribidasari A; Saepudin, Endang; Wardah, Habibah; Harmesa; Dewangga, Netra; Einaga, Yasuaki

2012-11-20

346

Multichannel Boron Doped Nanocrystalline Diamond Ultramicroelectrode Arrays: Design, Fabrication and Characterization  

PubMed Central

We report on the fabrication and characterization of an 8 × 8 multichannel Boron Doped Diamond (BDD) ultramicro-electrode array (UMEA). The device combines both the assets of microelectrodes, resulting from conditions in mass transport from the bulk solution toward the electrode, and of BDD's remarkable intrinsic electrochemical properties. The UMEAs were fabricated using an original approach relying on the selective growth of diamond over pre-processed 4 inches silicon substrates. The prepared UMEAs were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results demonstrated that the electrodes have exhibited a very fast electrode transfer rate (k0) up to 0.05 cm·s?1 (in a fast redox couple) and on average, a steady state limiting current (in a 0.5 M potassium chloride aqueous solution containing 1 mM Fe(CN)64? ion at 100 mV·s?1) of 1.8 nA. The UMEAs are targeted for electrophysiological as well as analytical applications.

Kiran, Raphael; Rousseau, Lionel; Lissorgues, Gaelle; Scorsone, Emmanuel; Bongrain, Alexandre; Yvert, Blaise; Picaud, Serge; Mailley, Pascal; Bergonzo, Philippe

2012-01-01

347

Non-enzymatic electrochemical detection of glycerol on boron-doped diamond electrode.  

PubMed

A non-enzymatic direct electrochemical glycerol detection method at a commercial boron-doped diamond (BDD) electrode in 0.1 M NaOH supporting electrolyte was developed. All the used electrochemical techniques proved useful features for the oxidation and direct amperometric determination of glycerol at a BDD electrode in 0.1 M NaOH aqueous solution. It was found that the direct electrooxidation of glycerol on the BDD electrode requires both adsorbed glycerol and hydroxyls at the electrode surface. Also, the sp(2) carbon did not allow enhancement of the glycerol oxidation process. The electronalytical sensitivity for the determination of glycerol at the BDD electrode ranged from 0.040 to 0.226 ?A mM(-1) as a function of the technique used. The highest electroanalytical sensitivity for the determination of glycerol at the BDD electrode was reached in batch system amperometric quantification under stirring conditions. Performed recovery studies indicated that it is possible to determine glycerol in real samples, and the proposed batch system analysis-based methodology can be a valuable tool for practical glycerol analysis. PMID:22159176

Pop, Aniela; Manea, Florica; Radovan, Ciprian; Dascalu, Dana; Vaszilcsin, Nicolae; Schoonman, Joop

2012-02-01

348

Electrochemical inactivation kinetics of boron-doped diamond electrode on waterborne pathogens.  

PubMed

A boron-doped diamond (BDD) electrode was constructed as a water disinfector for the inactivation of water borne pathogens. The bactericidal effect of the disinfector was evaluated on artificially contaminated waters containing, respectively, Escherichia coli, Pseudomonas aeruginosa and Legionella pneumophila at high density. By treating the bacterial suspensions with 4 V of constant voltage between the BDD and the counter-electrode for 50 min, the population of E. coli and P. aeruginosa decreased from (10E + 7-8 colony-forming unit mL(-1)) to below the detection limits of the colony-formation method. Meanwhile, L. pneumophila were reduced to virtually zero when analyzed by fluorescence-based staining. The influences of production parameters (voltage, NaCl concentration and flow rate) on the disinfection kinetics of the BDD disinfector were examined with respect to operational conditions. Voltage was the most significant factor for adjusting the extent of electrolysis, followed by NaCl concentration and flow rate, to influence the disinfection efficiency. The disinfection of natural river water samples containing numerous microbes was performed for a practicability investigation of the BDD electrode. Approximately 99.99% bactericidal efficiency was confirmed by viability detection for E. coli and common germs in treated water. The results showed that the BDD electrode is a promising tool for various wastewater disinfections to combat waterborne diseases. PMID:21976200

Yao, Yanyan; Kubota, Yoshinobu; Murakami, Taketoshi; Ochiai, Tsuyoshi; Ishiguro, Hitoshi; Nakata, Kazuya; Fujishima, Akira

2011-09-01

349

Electrochemical incineration of sulfanilic acid at a boron-doped diamond anode.  

PubMed

The anodic oxidation of sulfanilic acid solutions has been studied in acidic medium using a divided cell with a boron-doped diamond (BDD) anode and a stainless steel cathode. Overall mineralization was achieved under all experimental conditions tested due to the efficient destruction of sulfanilic acid and all its by-products with hydroxyl radicals generated at the BDD anode from water oxidation. The alternative use of an undivided cell with the same electrodes gave rise to the coating of the cathode with polymeric compounds, thus preventing the complete electrochemical incineration of sulfanilic acid. The solutions treated in the anodic compartment of the divided cell were degraded at similar rate under pH regulation within the pH interval 2.0-6.0. The mineralization current efficiency was enhanced when the applied current decreased and the initial substrate concentration increased. The decay of sulfanilic acid was followed by reversed-phase HPLC, showing a pseudo first-order kinetics. Hydroquinone and p-benzoquinone were identified as aromatic intermediates by gas chromatography-mass spectrometry and/or reversed-phase HPLC. Maleic, acetic, formic, oxalic and oxamic acids were detected as generated carboxylic acids by ion-exclusion HPLC. Ionic chromatographic analysis of electrolyzed solutions revealed that the N content of sulfanilic acid was mainly released as NH(4)(+) ion and in much smaller proportion as NO(3)(-) ion. PMID:22365277

El-Ghenymy, Abdellatif; Arias, Conchita; Cabot, Pere Lluís; Centellas, Francesc; Garrido, José Antonio; Rodríguez, Rosa María; Brillas, Enric

2012-06-01

350

Electrochemical oxidation of nitrogen-heterocyclic compounds at boron-doped diamond electrode.  

PubMed

Nitrogen-heterocyclic compounds (NHCs) are toxic and bio-refractory contaminants widely spread in environment. This study investigated electrochemical degradation of NHCs at boron-doped diamond (BDD) anode with particular attention to the effect of different number and position of nitrogen atoms in molecular structure. Five classical NHCs with similar structures including indole (ID), quinoline (QL), isoquinoline (IQL), benzotriazole (BT) and benzimidazole (BM) were selected as the target compounds. Results of bulk electrolysis showed that degradation of all NHCs was fit to a pseudo first-order equation. The five compounds were degraded with the following sequence: ID>QL>IQL>BT>BM in terms of their rates of oxidation. Quantum chemical calculation was combined with experimental results to describe the degradation character of NHCs at BDD anode. A linear relationship between degradation rate and delocalization energy was observed, which demonstrated that electronic charge was redistributed through the conjugation system and accumulated at the active sites under the attack of hydroxyl radicals produced at BDD anode. Moreover, atom charge was calculated by semi empirical PM3 method and active sites of NHCs were identified respectively. Analysis of intermediates by GC-MS showed agreement with calculation results. PMID:22071370

Xing, Xuan; Zhu, Xiuping; Li, Hongna; Jiang, Yi; Ni, Jinren

2012-01-01

351

Electrochemical incineration of dimethyl phthalate by anodic oxidation with boron-doped diamond electrode.  

PubMed

The anodic oxidation of aqueous solutions containing dimethyl phthalate (DMP) up to 125 mg/L with sodium sulfate (Na2SO4) as supporting electrolyte within the pH range 2.0-10.0 was studied using a one-compartment batch reactor employing a boron-doped diamond (BDD) as anode. Electrolyses were carried out at constant current density (1.5-4.5 mA/cm2). Complete mineralization was always achieved owing to the great concentration of hydroxyl radical (*OH) generated at the BDD surface. The effects of pH, apparent current density and initial DMP concentration on the degradation rate of DMP, the specific charge required for its total mineralization and mineralization current efficiency were investigated systematically. The mineralization rate of DMP was found to be pH-independent and to increase with increasing applied current density. Results indicated that this electrochemical process was subjected, at least partially, to the mass transfer of organics onto the BDD surface. Kinetic analysis of the temporal change of DMP concentration during electrolysis determined by High Performance Liquid Chromatography (HPLC) revealed that DMP decay under all tested conditions followed a pseudo first-order reaction. Aromatic intermediates and generated carboxylic acids were identified by Gas Chromatography-Mass Spectrometry (GC-MS) and a general pathway for the electrochemical incineration of DMP on BDD was proposed. PMID:19999984

Hou, Yining; Qu, Jiuhui; Zhao, Xu; Liu, Huijuan

2009-01-01

352

Effect of nitro substituent on electrochemical oxidation of phenols at boron-doped diamond anodes.  

PubMed

In order to investigate nitro-substitutent's effect on degradation of phenols at boron-doped diamond (BDD) anodes, cyclic voltammetries of three nitrophenol isomers: 2-nitrophenol (2NP), 3-nitrophenol (3NP) and 4-nitrophenol (4NP) were studied, and their bulk electrolysis results were compared with phenol's (Ph) under alkaline condition. The voltammetric study showed nitrophenols could be attacked by hydroxyl radicals and nitro-group was released from the aromatic ring. Results of bulk electrolysis showed degradation of all phenols were fit to a pseudo first-order equation and followed in this order: 2NP>4NP>3NP>Ph. Molecular structures, especially carbon atom charge, significantly influenced the electrochemical oxidation of these isomers. Intermediates were analyzed during the electrolysis process, and were mainly catechol, resorcinol, hydroquinone, and carboxylic acids, such as acetic acid and oxalic acid. A simple degradation pathway was proposed. Moreover, a linear increasing relationship between degradation rates and Hammett constants of the studied phenols was observed, which demonstrated that electrochemical oxidation of these phenols was mainly initiated by electrophilic attack of hydroxyl radicals at BDD anodes. PMID:20060999

Jiang, Yi; Zhu, Xiuping; Li, Hongna; Ni, Jinren

2010-02-01

353

Mineralization of bisphenol A (BPA) by anodic oxidation with boron-doped diamond (BDD) electrode.  

PubMed

Anodic oxidation of bisphenol A (BPA), a representative endocrine disrupting chemical, was carried out using boron-doped diamond (BDD) electrode at galvanostatic mode. The electro-oxidation behavior of BPA at BDD electrode was investigated by means of cyclic voltammetric technique. The extent of degradation and mineralization of BPA were monitored by HPLC and total organic carbon (TOC) value, respectively. The results obtained, indicate that the BPA removal at BDD depends on the applied current density (Iappl), initial concentration of BPA, pH of electrolyte and supporting medium. Galvanostatic electrolysis at BDD anode cause concomitant generation of hydroxyl radical that leads to the BPA destruction. The kinetics for the BPA degradation follows a pseudo-first order reaction with a higher rate constant 12.8x10(-5) s(-1) for higher Iappl value 35.7 mA cm(-2), indicating that the oxidation reaction is limited by Iappl control. Complete mineralization of BPA was achieved regardless of the variables and accordingly the mineralization current efficiency was calculated from the TOC removal measurements. Considering global oxidation process, the effect of supporting electrolytes has been discussed in terms of the electro generated inorganic oxidants. The better performance of BDD anode was proved on a comparative study with Pt and glassy carbon under similar experimental conditions. A possible reaction mechanism for BPA degradation involving three main aromatic intermediates, identified by GC-MS analysis, was proposed. PMID:18023975

Murugananthan, M; Yoshihara, S; Rakuma, T; Shirakashi, T

2008-06-15

354

Energy consumption of electrooxidation systems with boron-doped diamond electrodes in the pulse current mode  

NASA Astrophysics Data System (ADS)

A pulse current technique was conducted in a boron-doped diamond (BDD) anode system for electrochemical wastewater treatment. Due to the strong generation and weak absorption of hydroxyl radicals on the diamond surface, the BDD electrode possesses a powerful capability of electrochemical oxidation of organic compounds, especially in the pulse current mode. The influences of pulse current parameters such as current density, pulse duty cycle, and frequency were investigated in terms of chemical oxygen demand (COD) removal, average current efficiency, and specific energy consumption. The results demonstrated that the relatively high COD removal and low specific energy consumption were obtained simultaneously only if the current density or pulse duty cycle was adjusted to a reasonable value. Increasing the frequency slightly enhanced the COD removal and average current efficiency. A pulse-BDD anode system showed a stronger energy saving ability than a constant-BDD anode system when the electrochemical oxidation of phenol of the two systems was compared. The results prove that the pulse current technique is more cost-effective and more suitable for a BDD anode system for real wastewater treatment. A kinetic analysis was presented to explain the above results.

Wei, Jun-jun; Gao, Xu-hui; Hei, Li-fu; Askari, Jawaid; Li, Cheng-ming

2013-01-01

355

Electrochemical degradation of PNP at boron-doped diamond and platinum electrodes.  

PubMed

The electrochemical degradation of p-nitrophenol (PNP) at boron-doped diamond (BDD) and platinum (Pt) anodes was studied by varying the parameters such as Cl(-) concentration, pH of aqueous medium and applied current density. The results obtained were explained in terms of in situ concomitant generation of hydroxyl radicals and chloride based oxidant species. The degradation of PNP was highly promoted in low concentration of NaCl electrolyte (less than 0.10 M), on contrary, the mineralization efficiency was poor at both BDD and Pt anodes with the NaCl concentration up to 0.20 M, which was ascribed to the formation of refractory chlorinated organic compounds. A maximum of 100% and 70% of COD removal was achieved in 5h of electrolysis period using both BDD and Pt anodes under similar experimental conditions. Kinetic study indicated that the degradation of PNP at BDD and Pt anodes followed pseudo-first-order reactions, and the reaction rate constant (k(s)) of the former was observed to be higher than that of the latter. Besides COD, conversion of PNP into various intermediate compounds and their degradations were also monitored. The mechanisms for PNP degradation at BDD and Pt anodes were proposed separately by considering the nature of respective intermediate species and their concentrations. PMID:23270953

Zhang, Yanrong; Yang, Nan; Murugananthan, Muthu; Yoshihara, Sachio

2013-01-15

356

Development of boron-doped diamond thin-films as voltammetric and amperometric detectors  

NASA Astrophysics Data System (ADS)

The utilization of boron-doped diamond thin-films for applications in electroanalysis was investigated. Voltammetric analysis in static solution, and amperometric detection coupled with flow injection analysis and HPLC were performed. The results were compared to those for glassy carbon. The electroactivity, the merit of detection figures, the adsorption of polar organic molecules, and the resistance to fouling were studied. Surface characterization was performed to elucidate the surface property-electroacticvity relationship. The results showed that diamond thin-films, compared with glassy carbon, had comparable electroactivity to simple electron transfer processes (e.g., Ru(NH3)6+2/+3, Fe(CN)6 -3/-4, IrCl6-2/-3, azide, chlorpromazine), but had lower electroactivity for the electron transfer processes involving surface-confined intermediate (e.g., hydrogen evolution, oxygen evolution, 4-methyl catechol, hydrazine). The diamond thin-films had a wide working potential up to 4.0 V in aqueous media. They also had small double layer capacitance, voltammetric background current, and amperometric residual current. These properties had leaded to higher signal-to-background ratios and signal-to-noise ratios. The diamond thin-films had lower limits of detection in voltammetric measurements of several analytes, and had lower limits of detection in amperometric measurements of all compounds studied. The diamond thin-films had negligible adsorption of polar organic molecules (e.g., anthraquinone 2,6-disulfonate, chlorpromazine), compared to glassy carbon. This is due to the fact that the diamond surfaces are primarily composed of sp3 carbon and hydrogen terminated. This leaded to less decay of the electroactivity by storage and operation, and higher resistance to fouling. The surface property-electroactivity relationship depends on the specific mechanism for electron transfer. The extent of non-diamond impurities (e.g., oxygen evolution), diamond crystalline size, surface termination (e.g., azide), and surface boron sites (hydrazine) could all affect the electroactivity for diamond thin-films.

Xu, Jishou

2000-10-01

357

Influence of Ball-Milling Treatment of B Original Powder on the Phase Formation and Critical Current Density of Graphite Doped MgB2  

NASA Astrophysics Data System (ADS)

In present work, the sintering process and superconducting properties of graphite doped MgB2 prepared with milled B original powder were investigated. It is found that ball milling treatment of B original powder obviously suppresses the solid-solid reaction between Mg and B, whereas it enhances their liquid-solid reaction during the subsequent sintering process of these graphite doped MgB2 bulks. Ball milling treatment of B original powder can also promote C substitution for B sites in MgB2 crystal lattice in the graphite-doped samples, and thus obviously increase their values of Jc at high fields. Moreover, ball milling also refines MgB2 grains, enhancing grain boundary pinning and Jc at high fields.

Su, Xiaocheng; Jiang, Qingguo; Zuo, Anying

2014-04-01

358

Effect of boron doped fullerene C 60 film coating on the electrochemical characteristics of silicon thin film anodes for lithium secondary batteries  

Microsoft Academic Search

In this work, boron doped fullerene (B:C60) films were prepared by the radio frequency plasma assisted thermal evaporation technique for use as a coating material for the silicon thin film anode in lithium secondary batteries. Raman and XPS analyses revealed that the boron atoms were well inserted into the fullerene film lattices. The effect of the B:C60 film on the

Arenst Andreas Arie; Joong Kee Lee

2011-01-01

359

Advanced treatment of biologically pretreated coking wastewater by electrochemical oxidation using boron-doped diamond electrodes.  

PubMed

Electrochemical oxidation is a promising technology to treatment of bio-refractory wastewater. Coking wastewater contains high concentration of refractory and toxic compounds and the water quality usually cannot meet the discharge standards after conventional biological treatment processes. This paper initially investigated the electrochemical oxidation using boron-doped diamond (BDD) anode for advanced treatment of coking wastewater. Under the experimental conditions (current density 20-60mAcm(-2), pH 3-11, and temperature 20-60 degrees C) using BDD anode, complete mineralization of organic pollutants was almost achieved, and surplus ammonia-nitrogen (NH(3)-N) was further removed thoroughly when pH was not adjusted or at alkaline value. Moreover, the TOC and NH(3)-N removal rates in BDD anode cell were much greater than those in other common anode systems such as SnO(2) and PbO(2) anodes cells. Given the same target to meet the National Discharge Standard of China, the energy consumption of 64kWhkgCOD(-1) observed in BDD anode system was only about 60% as much as those observed in SnO(2) and PbO(2) anode systems. Further investigation revealed that, in BDD anode cell, organic pollutants were mainly degraded by reaction with free hydroxyl radicals and electrogenerated oxidants (S(2)O(8)(2-), H(2)O(2), and other oxidants) played a less important role, while direct electrochemical oxidation and indirect electrochemical oxidation mediated by active chlorine can be negligible. These results showed great potential of BDD anode system in engineering application as a final treatment of coking wastewater. PMID:19595422

Zhu, Xiuping; Ni, Jinren; Lai, Peng

2009-09-01

360

Boron-doped diamond electrodes for the electrochemical oxidation and cleavage of peptides.  

PubMed

Electrochemical oxidation of peptides and proteins is traditionally performed on carbon-based electrodes. Adsorption caused by the affinity of hydrophobic and aromatic amino acids toward these surfaces leads to electrode fouling. We compared the performance of boron-doped diamond (BDD) and glassy carbon (GC) electrodes for the electrochemical oxidation and cleavage of peptides. An optimal working potential of 2000 mV was chosen to ensure oxidation of peptides on BDD by electron transfer processes only. Oxidation by electrogenerated OH radicals took place above 2500 mV on BDD, which is undesirable if cleavage of a peptide is to be achieved. BDD showed improved cleavage yield and reduced adsorption for a set of small peptides, some of which had been previously shown to undergo electrochemical cleavage C-terminal to tyrosine (Tyr) and tryptophan (Trp) on porous carbon electrodes. Repeated oxidation with BDD electrodes resulted in progressively lower conversion yields due to a change in surface termination. Cathodic pretreatment of BDD at a negative potential in an acidic environment successfully regenerated the electrode surface and allowed for repeatable reactions over extended periods of time. BDD electrodes are a promising alternative to GC electrodes in terms of reduced adsorption and fouling and the possibility to regenerate them for consistent high-yield electrochemical cleavage of peptides. The fact that OH-radicals can be produced by anodic oxidation of water at elevated positive potentials is an additional advantage as they allow another set of oxidative reactions in analogy to the Fenton reaction, thus widening the scope of electrochemistry in protein and peptide chemistry and analytics. PMID:23763302

Roeser, Julien; Alting, Niels F A; Permentier, Hjalmar P; Bruins, Andries P; Bischoff, Rainer

2013-07-16

361

Essential explanation of the strong mineralization performance of boron-doped diamond electrodes.  

PubMed

Electrochemical oxidation of p-nitrophenol was examined using differentanodic materials, including T/boron-doped diamond (BDD), Ti/SnO2-Sb/PbO2, and Ti/SnO2-Sb anodes. The results demonstrated that Ti/BDD anodes had a much stronger mineralization performance than the other two anodes. Furthermore, it was found that hydroxyl radicals could mainly exist as free hydroxyl radicals at BDD anodes, which could react with organic compounds effectively. This implied that the dominant mechanism for a much higher mineralization capacity of BDD anodes would be attributed to the existence of free hydroxyl radicals in the BDD anode cell rather than adsorbed hydroxyl radicals on the BDD anode. To further corroborate this hypothesis, electrochemical oxidation of p-substituted phenols (p-nitrophenol, p-hydroxybenzaldehyde, phenol, p-cresol, and p-methoxyphenol) was examined at the Ti/BDD, Ti/SnO2-Sb/ PbO2, and Ti/SnO2-Sb anodes, respectively. The study revealed that for Ti/BDD electrodes, the degradation rate of p-substituted phenols (k) increased with the increase of Hammett's constant (sigma), which confirmed the dominance of free hydroxyl radicals at BDD anodes and its effective reaction with organics therein. For Ti/SnO2-Sb/PbO2 electrodes, the degradation rate of p-substituted phenols (k) increased with the increase of initial surface concentration gamma (representing the adsorption capacity of phenols to electrode surface), which indicated that organic compounds mainly reacted with adsorbed hydroxyl radicals at PbO2 anodes. For Ti/SnO2-Sb electrodes, however, k increased with the increase of the integrated parameter S (representing the effects of both sigma and gamma), which implied that organic compounds reacted with both adsorbed hydroxyl radicals and free hydroxyl radicals at SnO2 anodes. PMID:18678026

Zhu, Xiuping; Tong, Meiping; Shi, Shaoyuan; Zhao, Huazhang; Ni, Jinren

2008-07-01

362

Electrochemical detection of sugar-related compounds using boron-doped diamond electrodes.  

PubMed

Electrochemical detection of sugar-related compounds was conducted using a boron-doped diamond (BDD) electrode as a detector for flow-injection analysis (FIA). Sugar-related compounds oxidize at high applied potentials, for which the BDD electrode is suitable for electrochemical measurements. Conditions for an FIA system with a BDD detector were optimized, and the following detection limits were achieved for sugar-related compounds: monosaccharides, 25-100 pmol; sugar alcohols, 10 pmol; and oligosaccharides, 10 pmol. The detection limit for monosaccharide D-glucose (Glu) was 105 pmol (S/N = 3). A linear range was acquired from the detection limit to 50 nmol, and the relative standard deviation was 0.65% (20 nmol, n = 6). A high-performance liquid chromatography (HPLC) column was added to the system between the sample injector and the detector and detection limits to the picomole level were achieved, which is the same for the HPLC system and the FIA system. The electrochemical oxidation reaction of Glu was examined using cyclic voltammetry with the BDD detector. The reaction proved to be irreversible, and proceeded according to the following two-step mechanism: (1) application of a high potential (2.00 V vs. Ag/AgCl) to the electrode causes water to electrolyze on the electrode surface with the simultaneous generation of a hydroxyl radical on the surface, and (2) the hydroxyl radical indirectly oxidizes Glu. Thus, Glu can be detected by an increase in the oxidation current caused by reactions with hydroxy radicals. PMID:22322804

Hayashi, Tomohisa; Sakurada, Ikuo; Honda, Kensuke; Motohashi, Shigeyasu; Uchikura, Kazuo

2012-01-01

363

Mechanism of perchlorate formation on boron-doped diamond film anodes.  

PubMed

This research investigated the mechanism of perchlorate (ClO(4)(-)) formation from chlorate (ClO(3)(-)) on boron-doped diamond (BDD) film anodes by use of a rotating disk electrode reactor. Rates of ClO(4)(-) formation were determined as functions of the electrode potential (2.29-2.70 V/standard hydrogen electrode, SHE) and temperature (10-40 °C). At all applied potentials and a ClO(3)(-) concentration of 1 mM, ClO(4)(-) production rates were zeroth-order with respect to ClO(4)(-) concentration. Experimental and density functional theory (DFT) results indicate that ClO(3)(-) oxidation proceeds via a combination of direct electron transfer and hydroxyl radical oxidation with a measured apparent activation energy of 6.9 ± 1.8 kJ·mol(-1) at a potential of 2.60 V/SHE. DFT simulations indicate that the ClO(4)(-) formation mechanism involves direct oxidation of ClO(3)(-) at the BDD surface to form ClO(3)(•), which becomes activationless at potentials > 0.76 V/SHE. Perchloric acid is then formed via the activationless homogeneous reaction between ClO(3)(•) and OH(•) in the diffuse layer next to the BDD surface. DFT simulations also indicate that the reduction of ClO(3)(•) can occur at radical sites on the BDD surface to form ClO(3)(-) and ClO(2), which limits the overall rate of ClO(4)(-) formation. PMID:22029642

Azizi, Orchideh; Hubler, David; Schrader, Glenn; Farrell, James; Chaplin, Brian P

2011-12-15

364

Electrical transport properties of the Si-doped cubic boron nitride thin films prepared by in situ cosputtering  

SciTech Connect

Si-doped cubic boron nitride (c-BN) films with various Si concentrations were achieved by in situ cosputtering during ion beam assisted deposition. Effects of the Si concentration and rapid thermal annealing (RTA) conditions on the electrical transport properties of Si-doped c-BN thin films were investigated systematically. The results suggest that the optimum RTA condition is at the temperature of 1000 deg. C for 3 min. The resistance of Si-doped c-BN films gradually decreases as the Si concentration increases, indicating an electrical doping effect of the Si impurity. The temperature dependent electrical conductivity of the Si-doped c-BN films suggests that different conduction mechanisms are dominant over the different temperature ranges. Based on the Davis-Mott model, we propose that the extended-state conduction, band tail-state conduction and short-range hopping conduction are responsible for the respective temperature ranges. In addition, the reduction in activation energy of Si impurities is observed as the Si concentration increases.

Ying, J.; Zhang, X. W.; Yin, Z. G.; Tan, H. R.; Zhang, S. G.; Fan, Y. M. [Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)

2011-01-15

365

Silver on diamond Schottky diodes formed on boron doped hot-filament chemical vapor deposited polycrystalline diamond films  

SciTech Connect

Schottky diodes were fabricated using sputter deposited silver contacts to boron doped polycrystalline diamond thin films grown by a hot-filament chemical vapor deposition process with trimethyl borate as an {ital in} {ital situ} dopant source. High forward current density and a high forward-to-reverse current ratio were exhibited by these diodes. Current density-voltage and capacitance-voltage-frequency characteristics of these diodes are very similar to those of Schottky diodes fabricated using a single-crystal diamond substrate.

Zhao, G.; Stacy, T.; Charlson, E.J.; Charlson, E.M.; Chao, C.H.; Hajsaid, M.; Meese, J. (Department of Electrical and Computer Engineering, University of Missouri, Columbia, Missouri 65211 (United States)); Popovici, G.; Prelas, M. (Department of Nuclear Engineering, University of Missouri, Columbia, Missouri 65211 (United States))

1992-08-31

366

Electrochemical destruction of chlorophenoxy herbicides by anodic oxidation and electro-Fenton using a boron-doped diamond electrode  

Microsoft Academic Search

The degradation of herbicides 4-chlorophenoxyacetic acid (4-CPA), 4-chloro-2-methylphenoxyacetic acid (MCPA), 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) in aqueous medium of pH 3.0 has been comparatively studied by anodic oxidation and electro-Fenton using a boron-doped diamond (BDD) anode. All solutions are totally mineralized by electro-Fenton, even at low current, being the process more efficient with 1mM Fe2+ as catalyst. This

Enric Brillas; Birame Boye; Ignasi Sirés; José Antonio Garrido; Rosa Mar??a Rodr??guez; Conchita Arias; Pere-Llu??s Cabot; Christos Comninellis

2004-01-01

367

Simultaneous voltammetric determination of paracetamol and caffeine in pharmaceutical formulations using a boron-doped diamond electrode  

Microsoft Academic Search

A simple and highly selective electrochemical method was developed for the single or simultaneous determination of paracetamol (N-acetyl-p-aminophenol, acetaminophen) and caffeine (3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione) in aqueous media (acetate buffer, pH 4.5) on a boron-doped diamond (BDD) electrode using square wave voltammetry (SWV) or differential pulse voltammetry (DPV). Using DPV with the cathodically pre-treated BDD electrode, a separation of about 550mV between the

Bruna Cláudia Lourenção; Roberta Antigo Medeiros; Romeu C. Rocha-Filho; Luiz Henrique Mazo; Orlando Fatibello-Filho

2009-01-01

368

Electrochemical combustion of herbicide mecoprop in aqueous medium using a flow reactor with a boron-doped diamond anode  

Microsoft Academic Search

The anodic oxidation of 1.8l of solutions with mecoprop (2-(4-chloro-2-methylphenoxy)-propionic acid or MCPP) up to 0.64gl?1 in Na2SO4 as background electrolyte within the pH range 2.0–12.0 has been studied using a flow plant containing a one-compartment filter-press electrolytic reactor with a boron-doped diamond (BDD) anode and a stainless steel cathode, both of 20-cm2 area. Electrolyses carried out in batch under

Cristina Flox; Pere Lluís Cabot; Francesc Centellas; José Antonio Garrido; Rosa María Rodríguez; Conchita Arias; Enric Brillas

2006-01-01

369

Solar photoelectro-Fenton degradation of cresols using a flow reactor with a boron-doped diamond anode  

Microsoft Academic Search

The solar photoelectro-Fenton degradation of 2.5l of acidic solutions containing o-cresol, m-cresol and p-cresol up to ca. 1gl?1, 0.05M Na2SO4 and Fe2+ as catalyst has been studied using a flow plant with a one-compartment filter-press electrolytic reactor with a boron-doped diamond (BDD) anode and an O2-diffusion cathode, both of 20-cm2 area, coupled to a solar photoreactor. In this environmentally friendly

Cristina Flox; Pere-Lluís Cabot; Francesc Centellas; José Antonio Garrido; Rosa María Rodríguez; Conchita Arias; Enric Brillas

2007-01-01

370

Oxidative synthesis of highly fluorescent boron/nitrogen co-doped carbon nanodots enabling detection of photosensitizer and carcinogenic dye.  

PubMed

Current research efforts have demonstrated the facile hydrothermal oxidative synthetic route to develop highly fluorescent boron/nitrogen co-doped carbon nanodots (CNDs). During this process, N-(4-hydroxyphenyl)glycine served as a source of N doping and a carbon precursor as well, while boric acid H3BO3 is used as an oxidizing agent in the N2 environment. Surface passivation through ultrasonic treatment of CNDs was performed to induce modifications by using various surface passivating agents. Polyethyleneimine (PEI) remarkably enhanced the fluorescence performance and monodispersity of polymerized carbon nanodots (P-CNDs) in aqueous phase with an enhanced quantum yield of 23.71%, along with an increase in size from ~3 nm to ~200 nm. For characterization of CNDs and P-CNDs, UV, infrared, photoluminescence, transmission electron microscopy, x-ray photoelectron spectra, and atomic force microscopy techniques were utilized. Application potentials of synthesized P-CNDs were developed via introduction of protoporphyrin (PPD, a photosensitizer) which has great doping affinity with polymer PEI to switch-off the fluorescence of P-CNDs, leading to the production of dye-doped nanoprobes. Fluorescence resonance energy transfer (FRET) was also observed during dye-doping, and PPD was detected with a limit of detection (LOD, 3?) of 15 pM. The fluorescence recovery of this switched-off nanoprobe was made possible by using Sudan red III (carcinogenic dye), which was oxidized by PPD doped in P-CNDs. Sudan red III was detected in the concentration range of 9.9 pM-0.37 nM. Meanwhile, it was also confirmed that the dye-doped nanoprobe is highly selective and exceptionally sensitive to detect this carcinogenic agent in commercial products with a LOD (3?) of 90 fM. PMID:24083490

Jahan, Shanaz; Mansoor, Farrukh; Naz, Shagufta; Lei, Jianping; Kanwal, Shamsa

2013-11-01

371

Insight into the effect of boron doping on sulfur/carbon cathode in lithium-sulfur batteries.  

PubMed

To exploit the high energy density of lithium-sulfur batteries, porous carbon materials have been widely used as the host materials of the S cathode. Current studies about carbon hosts are more frequently focused on the design of carbon structures rather than modification of its properties. In this study, we use boron-doped porous carbon materials as the host material of the S cathode to get an insightful investigation of the effect of B dopant on the S/C cathode. Powder electronic conductivity shows that the B-doped carbon materials exhibit higher conductivity than the pure analogous porous carbon. Moreover, by X-ray photoelectron spectroscopy, we prove that doping with B leads to a positively polarized surface of carbon substrates and allows chemisorption of S and its polysulfides. Thus, the B-doped carbons can ensure a more stable S/C cathode with satisfactory conductivity, which is demonstrated by the electrochemical performance evaluation. The S/B-doped carbon cathode was found to deliver much higher initial capacity (1300 mA h g(-1) at 0.25 C), improved cyclic stability, and rate capability when compared with the cathode based on pure porous carbon. Electrochemical impedance spectra also indicate the low resistance of the S/B-doped C cathode and the chemisorption of polysulfide anions because of the presence of B. These features of B doping can play the positive role in the electrochemical performance of S cathodes and help to build better Li-S batteries. PMID:24764111

Yang, Chun-Peng; Yin, Ya-Xia; Ye, Huan; Jiang, Ke-Cheng; Zhang, Juan; Guo, Yu-Guo

2014-06-11

372

Growth of polycrystalline diamond over glassy carbon and graphite electrode Materials  

SciTech Connect

Boron-doped polycrystalline diamond thin films were grown over glassy carbon electrode material and POCO graphite by a microwave plasma-assisted chemical vapor deposition (CVD) using a gas mixture of methane and hydrogen. As-deposited films were analyzed by scanning electron microscopy (SEM) and Raman spectroscopy for their morphology and chemical nature, respectively the diamond films grown over glassy carbon and graphite electrode material may have some use in electroanalysis since the doped diamond films are electrically conductive, erosion resistant, and chemically inert.

Ramesham, R.; Askew, R.F.; Rose, M.F. (Auburn Univ., AL (United States). Space Power Inst.); Loo, B.H. (Univ. of Alabama, Huntsville, AL (United States). Dept. of Chemistry)

1993-10-01

373

Oxygen Reduction: Nitrogen-Doped Holey Graphitic Carbon from 2D Covalent Organic Polymers for Oxygen Reduction (Adv. Mater. 20/2014).  

PubMed

L. Dai, D. Cao, and co-workers develop on page 3315 a new strategy to obtain N-doped holey graphitic carbon materials using covalent organic polymer precursors with controlled locations for the N-atoms. These N-doped holey graphene analogues are promising candidates for efficient energy conversion and storage, particularly as efficient metal-free electrocatalysts for oxygen reduction reaction in fuel cells. PMID:24852713

Xiang, Zhonghua; Cao, Dapeng; Huang, Ling; Shui, Jianglan; Wang, Min; Dai, Liming

2014-05-01

374

Retention of enzyme activity with a boron-doped diamond electrode in the electro-oxidative nitration of lysozyme  

PubMed Central

In this paper we report the successful use of a non-metallic electrode material, boron-doped diamond (BDD), for the anodic electro-oxidative modification of hen egg white lysozyme (HEWL). Platinum electrodes can give rise to loss of activity of HEWL in electrosynthetic studies, whereas activity is retained on boron-doped diamond which is proposed as an effective substitute material for this purpose. We also compare literature methods of electrode pre-treatment to determine the most effective in electrosynthesis. Our findings show a decrease in total nitroprotein yield with decreasing nitrite concentration and an increase with increasing solution pH, confirming that, at a BDD electrode, the controlling factor remains the concentration of tyrosine phenolate anion. Purification of mono- and bis-nitrated HEWL and assay of enzymic activity showed better retention of activity at BDD electrode surfaces when compared to platinum. The products from electro-oxidation of HEWL at BDD were confirmed by electrospray ionization Fourier transform ion cyclotron resonance (ESI-FT-ICR) mass spectrometry, which revealed unique mass increases of +45 and +90 Da for the mono- and bis-nitrated lysozyme, respectively, corresponding to nitration at tyrosine residues. The nitration sites were confirmed as Tyr23 and Tyr20.

Iniesta, Jesus; Esclapez-Vicente, Maria Deseada; Heptinstall, John; Walton, David J.; Peterson, Ian R.; Mikhailov, Victor A.; Cooper, Helen J.

2010-01-01

375

Catalytic activity of platinum nanoparticles on highly boron-doped and 100-oriented epitaxial diamond towards HER and HOR.  

PubMed

Platinum nanoparticles supported on boron-doped single-crystalline diamond surfaces were used as a model system to investigate the catalytic activity with respect to the influence of particle morphology, particle density and surface preparation of the diamond substrates. We report on the preparation, characterization and activity regarding hydrogen evolution reaction (HER) and hydrogen oxidation reaction (HOR) of these Pt/diamond electrodes. Two kinds of diamond layers with boron doping above 10(20) cm(-3) were grown epitaxially on (100)-oriented diamond substrates; post-treatments of wet chemical oxidation and radio frequency (rf) oxygen plasma treatments were applied. Electrochemical deposition of Pt was performed using a potentiostatic double-pulse technique, which allowed variation of the particle size in the range between 1 nm and 15 nm in height and 5 nm and 50 nm in apparent radius, while keeping the particle density constant. Higher nucleation densities on the plasma processed surface at equal deposition parameters could be related to the plasma-induced surface defects. Electrochemical characterization shows that the platinum particles act as nanoelectrodes and form an ohmic contact with the diamond substrate. The catalytic activity regarding HER and HOR of the platinum nanoparticles exhibits no dependence on the particle size down to particle heights of ?1 nm. The prepared Pt on diamond(100) samples show a similar platinum-specific activity as bulk platinum. Therefore, while keeping the activity constant, the well-dispersed particles on diamond offer an optimized surface-to-material ratio. PMID:21687867

Brülle, Tine; Denisenko, Andrej; Sternschulte, Hadwig; Stimming, Ulrich

2011-07-28

376

CE with a boron-doped diamond electrode for trace detection of endocrine disruptors in water samples.  

PubMed

Off-line SPE and CE coupled with electrochemical detection have been used for the determination of bisphenol A (BPA), bisphenol F, 4-ethylphenol, and bisphenol A diglycidyl ether in bottled drinking water. The use of boron-doped diamond electrode as an electrochemical detector in amperometric mode that provides a favorable analytical performance for detecting these endocrine-disrupting compounds, such as lower noise levels, higher peak resolution with enhanced sensitivity, and improved resistance against electrode passivation. The oxidative electrochemical detection of the endocrine-disrupting compounds was accomplished by boron-doped diamond electrode poised at +1.4 V versus Ag/AgCl without electrode pretreatment. An off-line SPE procedure (Bond Elut® C18 SPE cartridge) was utilized to extract and preconcentrate the compounds prior to separation and detection. The minimum concentration detectable for all four compounds ranged from 0.01 to 0.06 ?M, having S/N equal to three. After exposing the plastic bottle water container under sunlight for 7 days, the estimated concentration of BPA in the bottled drinking water was estimated to be 0.03 ?M. This proposed approach has great potential for rapid and effective determination of BPA content present in water packaging of plastic bottles that have been exposed to sunlight for an extended period of time. PMID:23172695

Browne, Damien J; Zhou, Lin; Luong, John H T; Glennon, Jeremy D

2013-07-01

377

In situ DNA oxidative damage by electrochemically generated hydroxyl free radicals on a boron-doped diamond electrode.  

PubMed

In situ DNA oxidative damage by electrochemically generated hydroxyl free radicals has been directly demonstrated on a boron-doped diamond electrode. The DNA-electrochemical biosensor incorporates immobilized double-stranded DNA (dsDNA) as molecular recognition element on the electrode surface, and measures in situ specific binding processes with dsDNA, as it is a complementary tool for the study of bimolecular interaction mechanisms of compounds binding to DNA and enabling the screening and evaluation of the effect caused to DNA by radicals and health hazardous compounds. Oxidants, particularly reactive oxygen species (ROS), play an important role in dsDNA oxidative damage which is strongly related to mutagenesis, carcinogenesis, autoimmune inflammatory, and neurodegenerative diseases. The hydroxyl radical is considered the main contributing ROS to endogenous oxidation of cellular dsDNA causing double-stranded and single-stranded breaks, free bases, and 8-oxoguanine occurrence. The dsDNA-electrochemical biosensor was used to study the interaction between dsDNA immobilized on a boron-doped diamond electrode surface and in situ electrochemically generate hydroxyl radicals. Non-denaturing agarose gel-electrophoresis of the dsDNA films on the electrode surface after interaction with the electrochemically generated hydroxyl radicals clearly showed the occurrence of in situ dsDNA oxidative damage. The importance of the dsDNA-electrochemical biosensor in the evaluation of the dsDNA-hydroxyl radical interactions is clearly demonstrated. PMID:22335175

Oliveira, S Carlos B; Oliveira-Brett, Ana Maria

2012-03-13

378

Fluorine and boron co-doped diamond-like carbon films deposited by pulsed glow discharge plasma immersion ion processing  

NASA Astrophysics Data System (ADS)

Fluorine (F) and boron (B) co-doped diamond-like carbon (FB-DLC) films were prepared on different substrates by the plasma immersion ion processing (PIIP) technique. A pulse glow discharge plasma was used for the PIIP deposition and was produced at a pressure of 1.33 Pa from acetylene (C2H2), diborane (B2H6), and hexafluoroethane (C2F6) gas. Films of FB-DLC were deposited with different chemical compositions by varying the flow ratios of the C2H2, B2H6, and C2F6 source gases. The incorporation of B2H6 and C2F6 into PIIP deposited DLC resulted in the formation of F-C and B-C hybridized bonding structures. The levels of the F and B concentrations effected the chemical bonding and the physical properties as was evident from the changes observed in density, hardness, stress, friction coefficient, and contact angle of water on films. Compared to B-doped or F-doped DLC films, the F and B co-doping of DLC during PIIP deposition resulted in the formation of films that possessed a reduced hydrogen concentration and stress, while maintaining a high hardness, low friction coefficient, and high wetting contact angle.

He, Xiao-Ming; Hakovirta, M.; Peters, A. M.; Taylor, B.; Nastasi, M.

2002-05-01

379

Mineralization of salicylic acid in acidic aqueous medium by electrochemical advanced oxidation processes using platinum and boron-doped diamond as anode and cathodically generated hydrogen peroxide.  

PubMed

Solutions containing 164 mg L(-1) salicylic acid of pH 3.0 have been degraded by electrochemical advanced oxidation processes such as anodic oxidation, anodic oxidation with electrogenerated H(2)O(2), electro-Fenton, photoelectro-Fenton and solar photoelectro-Fenton at constant current density. Their oxidation power has been comparatively studied in a one-compartment cell with a Pt or boron-doped diamond (BDD) anode and a graphite or O(2)-diffusion cathode. In the three latter procedures, 0.5mM Fe(2+) is added to the solution to form hydroxyl radical (()OH) from Fenton's reaction between Fe(2+) and H(2)O(2) generated at the O(2)-diffusion cathode. Total mineralization is attained for all methods with BDD and for photoelectro-Fenton and solar photoelectro-Fenton with Pt. The poor decontamination achieved in anodic oxidation and electro-Fenton with Pt is explained by the slow removal of most pollutants by ()OH formed from water oxidation at the Pt anode in comparison to their quick destruction with ()OH produced at BDD. ()OH generated from Fenton's reaction oxidizes rapidly all aromatic pollutants, but it cannot destroy final Fe(III)-oxalate complexes. Solar photoelectro-Fenton treatments always yield quicker degradation rate due to the very fast photodecarboxylation of these complexes by UVA irradiation supplied by solar light. The effect of current density on the degradation rate, efficiency and energy cost of all methods is examined. The salicylic acid decay always follows a pseudo-first-order kinetics. 2,3-Dihydroxybenzoic, 2,5-dihydroxybenzoic, 2,6-dihydroxybenzoic, alpha-ketoglutaric, glycolic, glyoxylic, maleic, fumaric, malic, tartronic and oxalic acids are detected as oxidation products. A general reaction sequence for salicylic acid mineralization considering all these intermediates is proposed. PMID:17692891

Guinea, Elena; Arias, Conchita; Cabot, Pere Lluís; Garrido, José Antonio; Rodríguez, Rosa María; Centellas, Francesc; Brillas, Enric

2008-01-01

380

Roughness-based monitoring of transparency and conductivity in boron-doped ZnO thin films prepared by spray pyrolysis  

SciTech Connect

Graphical abstract: Display Omitted Highlights: ? We report surface roughness dependent transparency and conductivity in ZnO films. ? The surface roughness with respected to boron doping concentrations is studied. ? Boron doped and pristine Zinc oxide thin films have showed ?95% transmittance. ? Increased carrier concentration of 9.21 × 10{sup 21} cm{sup ?3} revealed from Hall measurement. -- Abstract: Sprayed polycrystalline ZnO and boron-doped ZnO thin films composed of spherical grains of 25–32 nm in diameters are used in roughness measurement and further correlated with the transparency and the conductivity characteristics. The surface roughness is increased up to Zn{sub 0.98}B{sub 0.02}O and then declined at higher boron concentrations. The sprayed ZnO films revealed ?95% transmittance in the visible wavelength range, 1.956 × 10{sup ?4} ? cm electrical resistivity, 46 cm{sup 2}/V s Hall mobility and 9.21 × 10{sup 21} cm{sup ?3} charge carrier concentration. The X-ray photoelectron spectroscopy study has confirmed 0.15 eV binding energy change for Zn 2p{sub 3/2} when 2 at% boron content is mixed without altering electro-optical properties substantially. Finally, using soft modeling importance of these textured ZnO over non-textured films for enhancing the solar cells performance is explored.

Gaikwad, Rajendra S. [Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 130-650 (Korea, Republic of) [Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 130-650 (Korea, Republic of); Department of Physics, Yashwantrao Mohite College, Bharati Vidyapeeth Deemed University, Pune 411038, Maharashtra (India); Bhande, Sambhaji S. [Centre for Nanomaterials and Energy Devices, School of Physical Sciences, Swami Ramand Teerth Marathwada University, Nanded (India)] [Centre for Nanomaterials and Energy Devices, School of Physical Sciences, Swami Ramand Teerth Marathwada University, Nanded (India); Mane, Rajaram S., E-mail: rsmane_2000@yahoo.com [Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 130-650 (Korea, Republic of); Inorganic Nanomaterials Laboratory, Department of Chemistry, Hanyang University, Seoul 133-791 (Korea, Republic of); Centre for Nanomaterials and Energy Devices, School of Physical Sciences, Swami Ramand Teerth Marathwada University, Nanded (India); Pawar, Bhagwat N. [Department of Physics, Yashwantrao Mohite College, Bharati Vidyapeeth Deemed University, Pune 411038, Maharashtra (India)] [Department of Physics, Yashwantrao Mohite College, Bharati Vidyapeeth Deemed University, Pune 411038, Maharashtra (India); Gaikwad, Sanjay L. [Centre for Nanomaterials and Energy Devices, School of Physical Sciences, Swami Ramand Teerth Marathwada University, Nanded (India)] [Centre for Nanomaterials and Energy Devices, School of Physical Sciences, Swami Ramand Teerth Marathwada University, Nanded (India); Han, Sung-Hwan [Inorganic Nanomaterials Laboratory, Department of Chemistry, Hanyang University, Seoul 133-791 (Korea, Republic of)] [Inorganic Nanomaterials Laboratory, Department of Chemistry, Hanyang University, Seoul 133-791 (Korea, Republic of); Joo, Oh-Shim, E-mail: jookat@kist.ac.kr [Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 130-650 (Korea, Republic of)] [Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 130-650 (Korea, Republic of)

2012-12-15

381

Constructing 2D porous graphitic C3 N4 nanosheets/nitrogen-doped graphene/layered MoS2 ternary nanojunction with enhanced photoelectrochemical activity.  

PubMed

A 2D porous graphitic C3 N4 nanosheets/nitrogen-doped graphene/layered MoS2 ternary nanojunction is synthesized using a simple pyrolysis process followed by a hydrothermal treatment. The 2D ternary nanojunction exhibits significantly enhanced photoelectrochemical and photocatalytic activities due to the large contact area, efficient light absorption, and rapid charge separation and transport. PMID:23996281

Hou, Yang; Wen, Zhenhai; Cui, Shumao; Guo, Xiaoru; Chen, Junhong

2013-11-20

382

Solid sampling-graphite furnace atomic absorption spectrometry for the direct determination of boron in plant tissues  

Microsoft Academic Search

In this work, the potential of graphite furnace atomic absorption spectrometry for the direct determination of B in plant tissues has been investigated. Three certified reference materials (NIST SRM 1570a spinach leaves, NIST SRM 1573a tomato leaves and BCR CRM 679 white cabbage) were selected for this study, the goal always being to develop a fast procedure that could be

M. Resano; J. Briceño; M. Aramendía; M. A. Belarra

2007-01-01

383

Dissolution Mediated Boron and Carbon Storage during Exhumation of HP Metapelites: Examples from New Hampshire Tourmaline-Graphite Intergrowths  

NASA Astrophysics Data System (ADS)

The dynamic of light elements (e.g. C,B) in subduction zones is a complex process ultimately governed by variables such as P, T, fH2 and pH. Interface phenomena at scales from the outcrop to intergranular surfaces play key chemical and mechanical roles on this dynamic (e.g. Galvez et al. 2013). We report here a petrological study of hydrated borosilicate tourmaline intergrown with graphite formed at the contact between igneous intrusives and high grade micaschists in New Hampshire graphite deposits (Rumble and Hoering, 1986). Our study includes Raman scattering, SEM, microprobe analysis and thermodynamic modeling, focusing on the Franklin Pierce and Walpole outcrops. Both localities experienced HP-HT metamorphism during the Acadian orogeny as well as complex metasomatic process during exhumation. The tourmaline-graphite intergrowths are structurally localized at and around contacts between an aplite sill and micaschists - biotite-muscovite-garnet-sillimanite-plagioclase-quartz-ilmenite - (Franklin Pierce), or along shear zones (Walpole) in veins. Tourmalines are dravitic in composition (i.e. Na, Mg rich with minor vacancy and Li content 0.2/0.1 a.p.f.u) and contain multiple primary tubular mixed fluid-solid inclusions containing graphite, quartz and gaseous CO2 and CH4. Sharp optical and compositional radial zonations are observed from core to rim in sections along and perpendicular to the c-axis. Blue-green cores are enriched in Mg and Ca (1.5/0.1 a.p.f.u respectively) whereas rims are enriched in Fe, Na and Ti (0.9/0.6/0.1 a.p.f.u respectively). Alternative interpretations in terms of sector zoning or compositional variability of the mineralizing fluid will be discussed. The carbonaceous material (CM) occurs primarily as flakes directly replacing biotite present in wall rocks. The structural ordering of CM, of unambiguous abiotic origin, reveals a material possessing the 3 dimensional structure of hexagonal graphite. Our results are critically compared to measurements done on other metasomatic or biogenic graphite displaying high structural ordering. Other textural habit of graphite are radiating crystals of graphite preferentially growing along crystalline planes of wall rock minerals (e.g. plagioclases) and at the interface between grain edge. We test whether a C and B(OH)3° (×As, Cu) rich acidic vapor unmixing from a salt-rich aqueous fluid exsolved from crystallizing igneous bodies can account for some geochemical and textural greisen-type metasomatic features of these outcrops. Other mechanical and geochemical processes participating in the process will be discussed. This work is direct evidence that respeciation and/or fluid-rock interaction at varying P,T,fH2,pH conditions of fluids during exhumation, as well as interaction between magmatic bodies and metasedimentary units play a key role in the cycling of light elements during exhumation. Rumble, D., III, and Hoering, T.C., 1986, Carbon isotope geochemistry of graphite vein deposits from New Hampshire, U.S.A: Geochimica et Cosmochimica Acta, v. 50, p. 1239-1247. Galvez ME, Beyssac O, Martinez I, Benzerara K, Chaduteau C, Malvoisin B, Malavieille J (2013) Graphite formation by carbonate reduction during subduction. Nature Geoscience 6 (6):473-477

Galvez, M.; Rumble, D.; Cody, G. D.; Sverjensky, D. A.

2013-12-01

384

Synthesis and investigation of boron-doped fullerene and scandium-containing fullerene  

Microsoft Academic Search

We report on the plasmachemical synthesis of fullerene derivatives containing boron and scandium. The synthesis was conducted\\u000a at atmospheric pressure in a carbon-helium plasma jet generated by an RF arc.

G. N. Churilov; A. S. Alikhanyan; M. I. Nikitin; G. A. Glushchenko; N. G. Vnukova; N. V. Bulina; A. L. Emelina

2003-01-01

385

Electrochemical treatment of wastewaters containing organic pollutants on boron-doped diamond electrodes: Prediction of specific energy consumption and required electrode area  

Microsoft Academic Search

A theoretical analysis is presented for the prediction of the specific energy consumption and the required electrode surface for the electrochemical combustion of organic compounds on synthetic boron-doped diamond (BDD) thin film electrodes. The model is formulated for a perfect mixed electrochemical reactor operated as a batch recirculation system under galvanostatic conditions. The anodic oxidation of organics is assumed to

M. Panizza; P. A. Michaud; G. Cerisola; Ch Comninellis

2001-01-01

386

A flow injection method for the analysis of tetracycline antibiotics in pharmaceutical formulations using electrochemical detection at anodized boron-doped diamond thin film electrode  

Microsoft Academic Search

A method using flow injection (FI) with amperometric detection at anodized boron-doped diamond (BDD) thin films has been developed and applied for the determination of tetracycline antibiotics (tetracycline, chlortetracycline, oxytetracycline and doxycycline). The electrochemical oxidation of the tetracycline antibiotics was studied at various carbon electrodes including glassy carbon (GC), as-deposited BDD and anodized BDD electrodes using cyclic voltammetry. The anodized

N. Wangfuengkanagul; W. Siangproh; O. Chailapakul

2004-01-01

387

Electroanalysis of sulfonamides by flow injection system\\/high-performance liquid chromatography coupled with amperometric detection using boron-doped diamond electrode  

Microsoft Academic Search

Sulfonamides (SAs) were electrochemically investigated using cyclic voltammetry at a boron-doped diamond (BDD) electrode. Comparison experiments were carried out using a glassy carbon electrode. The BDD electrode provided well-resolved oxidation, irreversible cyclic voltammograms and higher current signals when compared to the glassy carbon electrode. Results obtained from using the BDD electrode in a flow injection system coupled with amperometric detection

Anchana Preechaworapun; Suchada Chuanuwatanakul; Yasuaki Einaga; Kate Grudpan; Shoji Motomizu; Orawon Chailapakul

2006-01-01

388

Plasma-assisted Recoil Implantation for Shallow Boron Doping in Silicon  

Microsoft Academic Search

An ion beam mixing technique is used to fabricate ultra-shallow p+\\/n junctions for the application of sub-micron CMOS source\\/drain formation. In this method, a thin boron layer is first sputtered onto the Si wafer. Then -3kV argon Plasma Source Ion Implantation (PSII) drives the boron atoms into the Si substrate by means of ion beam mixing. This process avoids the

H. L. Liu; S. S. Gearhart; J. H. Booske; W. Wang

1997-01-01

389

Raman spectroscopy of graphene and graphite: Disorder, electron–phonon coupling, doping and nonadiabatic effects  

Microsoft Academic Search

We review recent work on Raman spectroscopy of graphite and graphene. We focus on the origin of the D and G peaks and the second order of the D peak. The G and 2D Raman peaks change in shape, position and relative intensity with number of graphene layers. This reflects the evolution of the electronic structure and electron–phonon interactions. We

Andrea C. Ferrari

2007-01-01

390

Influence of Boron doping on the structural, optical and electrical properties of CdO thin films by spray pyrolysis technique  

NASA Astrophysics Data System (ADS)

Cadmium oxide and Boron (B) doped Cadmium oxide thin films were deposited using spray pyrolysis technique. The structural, morphological, electrical and optical properties of undoped and B doped CdO films are analyzed by varying the dopant concentration in the solution. The structural study shows the polycrystalline nature and cubic structure of undoped and B doped CdO thin films. Surface morphological study reveals that the grains are spherical in shape. Optical and electrical studies showed n-type semiconducting nature and optical band gap of 2.44 eV of deposited thin films.

Velusamy, P.; Babu, R. Ramesh; Ramamurthi, K.

2014-04-01

391

Titanium Carbide-Graphite Composites.  

National Technical Information Service (NTIS)

Pure titanium carbide, titanium carbide with free graphite, titanium carbide/vanadium carbide alloy with free graphite, and titanium carbide with boron and free graphite were tested for friction and wear at 22,600, and 900 C. Test pins of the four composi...

D. Cummings

1991-01-01

392

Capacitance of p- and n-doped graphenes is dominated by structural defects regardless of the dopant type.  

PubMed

Graphene materials possess attractive properties that can be used for the fabrication of supercapacitors with enhanced energy-storage performance. It has been shown that both boron and nitrogen doping of graphene can improve the intrinsic capacitance of the material relative to the undoped precursor. We address the question of whether p-doping (using boron as dopant) or n-doping (using nitrogen as dopant) leads to increased capacitance relative to undoped graphene materials. Using thermal exfoliation we synthesized both boron- and nitrogen-doped graphene materials and measured capacitance relative to the undoped material. After a full characterization by SEM analysis, X-ray photoelectron spectroscopy, Raman spectroscopy, gamma-ray activation analysis, Brunauer-Emmett-Teller analysis, and electrochemical techniques we demonstrate that the doping process does not lead to enhancement of capacitive behavior and that the main characteristic influencing capacitance is the presence of structural defects within the graphitic structure, independent of doping level. PMID:24591401

Ambrosi, Adriano; Poh, Hwee Ling; Wang, Lu; Sofer, Zdenek; Pumera, Martin

2014-04-01

393

Direct electrochemistry of glucose oxidase and biosensing for glucose based on boron-doped carbon nanotubes modified electrode.  

PubMed

Due to their unique physicochemical properties, doped carbon nanotubes are now extremely attractive and important nanomaterials in bioanalytical applications. In this work, selecting glucose oxidase (GOD) as a model enzyme, we investigated the direct electrochemistry of GOD based on the B-doped carbon nanotubes/glassy carbon (BCNTs/GC) electrode with cyclic voltammetry. A pair of well-defined, quasi-reversible redox peaks of the immobilized GOD was observed at the BCNTs based enzyme electrode in 0.1M phosphate buffer solution (pH 6.98) by direct electron transfer between the protein and the electrode. As a new platform in glucose analysis, the new glucose biosensor based on the BCNTs/GC electrode has a sensitivity of 111.57 microA mM(-1)cm(-2), a linear range from 0.05 to 0.3mM and a detection limit of 0.01mM (S/N=3). Furthermore, the BCNTs modified electrode exhibits good stability and excellent anti-interferent ability to the commonly co-existed uric acid and ascorbic acid. These indicate that boron-doped carbon nanotubes are the good candidate material for the direct electrochemistry of the redox-active enzyme and the construction of the related enzyme biosensors. PMID:18178424

Deng, Chunyan; Chen, Jinhua; Chen, Xiaoli; Xiao, Chunhui; Nie, Lihua; Yao, Shouzhuo

2008-03-14

394

Luminescence properties of boron and nitrogen doped graphene quantum dots prepared from arc-discharge-generated doped graphene samples  

NASA Astrophysics Data System (ADS)

Substitution of heteroatoms in graphene is known to tailor its band gap. Another approach to alter the band gap of graphene is to create zero-dimensional graphene quantum dots (GQDs). Here we present the synthesis and photoluminescence properties of B-doped graphene quantum dots (B-GQDs) for the first time, having prepared the B-GQDs by chemical scissoring of B-doped graphene generated by arc-discharge in gas phase. We compare the photoluminescence properties of B-GQDs with nitrogen-doped GQDs and pristine GQDs. Besides, excitation wavelength independent PL emission, excellent upconversion of PL emission is observed in GQDs as well as B- and N-doped GQDs.

Dey, Sunita; Govindaraj, A.; Biswas, Kanishka; Rao, C. N. R.

2014-03-01

395

Effects of additive boron on HPHT diamond single crystals grown by TGM  

NASA Astrophysics Data System (ADS)

In this work, under pressure 5.4 GPa and temperature 1250-1400°C, large gem-diamond single crystals with perfect shape and different content of additive boron were synthesized using temperature gradient method. High-purity boron powders were added as boron source into the graphite powder, and the effects of additive boron on crystal growth habit were investigated in detail. The relationship between the growth rate and the amount of additive boron was studied. The scanning electron microscopy was employed to study the morphology of boron-doped diamond crystals. Raman spectroscopy and Hall measurements were used to investigate the crystal structures and the carrier concentration, respectively. The results show that with the increase of the content of boron added into graphite powder, the crystal growth rate and the carrier concentration increase firstly, and decrease afterwards, and the zone-center phonon line at 1332 cm-1 has small shift to lower energy. The defects occur on the crystal surface when excessive boron is added in the synthesis system.

Xiao, Hongyu; Qin, Yukun; Li, Shangsheng; Liang, Zhongzhu; Ma, Hongan; Jia, Xiapeng

2011-12-01

396

Remarkably low turn-on field emission in undoped, nitrogen-doped, and boron-doped graphene  

Microsoft Academic Search

Field emission studies have been carried out on undoped as well as N- and B-doped graphene samples prepared by arc-discharge method in a hydrogen atmosphere. These graphene samples exhibit very low turn-on fields. N-doped graphene shows the lowest turn-on field of 0.6 V\\/?m, corresponding to emission current density of 10 ?A\\/cm2. These characteristics are superior to the other types of

U. A. Palnitkar; Ranjit V. Kashid; Mahendra A. More; Dilip S. Joag; L. S. Panchakarla; C. N. R. Rao

2010-01-01

397

Remarkably low turn-on field emission in undoped, nitrogen-doped, and boron-doped graphene  

Microsoft Academic Search

Field emission studies have been carried out on undoped as well as N- and B-doped graphene samples prepared by arc-discharge method in a hydrogen atmosphere. These graphene samples exhibit very low turn-on fields. N-doped graphene shows the lowest turn-on field of 0.6 V\\/mum, corresponding to emission current density of 10 muA\\/cm2. These characteristics are superior to the other types of

U. A. Palnitkar; Ranjit V. Kashid; Mahendra A. More; Dilip S. Joag; L. S. Panchakarla; C. N. R. Rao

2010-01-01

398

The boron heterofullerenes C 59B and C 69B: generation, extraction, mass spectrometric and XPS characterization  

NASA Astrophysics Data System (ADS)

Boron heterofullerenes can be generated by arc evaporation of doped graphite rods in a modified fullerene reactor. According to mass spectrometric analysis only mono-substituted fullerenes like C 59B, C 69B and higher homologues can be extracted and enriched by the use of pyridine as the solvent. They are strong Lewis acids and undergo a decomposition reaction to boric acid with traces of oxygen. XPS analysis of the extracts reveals the boron in the fullerene cage to be in a higher oxidation state compared to ordinary boron-carbon compounds. The synthesis and extraction procedure opens a viable route for the macroscopic production of these compounds.

Muhr, H.-J.; Nesper, R.; Schnyder, B.; Kötz, R.

1996-02-01

399

Epitaxial growth of boron-doped graphene by thermal decomposition of B4C  

NASA Astrophysics Data System (ADS)

We grew graphene by thermal decomposition of B4C and investigated its features by high-resolution transmission electron microscope observations. At temperatures higher than 1600?°C in a vacuum, B4C decomposes and graphene forms epitaxially on its surface. The number and the morphology of the graphene layers depend on the surface orientation. An electron diffraction technique revealed the presence of a superstructure with a two-times larger unit cell, which is consistent with the structure of BC3. We have directly confirmed boron in the graphene layers by electron energy loss spectroscopy measurements and boron-mapping experiments.

Norimatsu, Wataru; Hirata, Koichiro; Yamamoto, Yuta; Arai, Shigeo; Kusunoki, Michiko

2012-08-01

400

Epitaxial growth of boron-doped graphene by thermal decomposition of B4C.  

PubMed

We grew graphene by thermal decomposition of B(4)C and investigated its features by high-resolution transmission electron microscope observations. At temperatures higher than 1600 °C in a vacuum, B(4)C decomposes and graphene forms epitaxially on its surface. The number and the morphology of the graphene layers depend on the surface orientation. An electron diffraction technique revealed the presence of a superstructure with a two-times larger unit cell, which is consistent with the structure of BC(3). We have directly confirmed boron in the graphene layers by electron energy loss spectroscopy measurements and boron-mapping experiments. PMID:22820622

Norimatsu, Wataru; Hirata, Koichiro; Yamamoto, Yuta; Arai, Shigeo; Kusunoki, Michiko

2012-08-01

401

Voltammetric determination of mixtures of caffeine and chlorogenic acid in beverage samples using a boron-doped diamond electrode.  

PubMed

Herein, a boron-doped diamond (BDD) electrode that is anodically pretreated was used for the simultaneous determination of caffeine (CAF) and chlorogenic acid (CGA) by cyclic and adsorptive stripping voltammetry. The dependence of peak current and potential on pH, scan rate, accumulation parameters and other experimental variables were studied. By using square-wave stripping mode after 60 s accumulation under open-circuit voltage, the BDD electrode was able to separate the oxidation peak potentials of CAF and CGA present in binary mixtures by about 0.4V in Britton-Robinson buffer at pH 1.0. The limits of detection were 0.107 µg mL(-1) (5.51×10(-7) M) for CAF, and 0.448 µg mL(-1) (1.26×10(-6) M) for CGA. The practical applicability of this methodology was tested in commercially available beverage samples. PMID:24148509

Yard?m, Yavuz; Keskin, Ertugrul; ?entürk, Zühre

2013-11-15

402

Controlling the diffusion profile of electroactive species for selective anodic stripping voltammetry of cadmium at boron-doped diamond electrodes.  

PubMed

Selective anodic stripping voltammetry of trace metal ions in a mixture solution with another interfering metal was developed based on Fick's law concerning the diffusion profile of interfering metals at the electrode surface after electrolysis treatment. A boron-doped diamond film was used as the sensing electrode, while a perforated carbon sheet was used for the interference-depleting electrode. The influence of the electrode distance and the time of electrolysis on the formation of the diffusion profile was studied. As a working model, the detection of cadmium with copper interference was investigated. The advantage of the method in comparison to general electrolysis was also discussed. The method offers a new perspective for improving the selective detection of metal ions by analyzing the diffusion profiles of the interfering species at the surface of electrodes. PMID:23147907

Sugitani, Ai; Watanabe, Takeshi; Ivandini, Tribidasari A; Iguchi, Tatsuo; Einaga, Yasuaki

2013-01-01

403

Electrochemical oxidation of phenol at boron-doped diamond electrode. Application to electro-organic synthesis and wastewater treatment.  

PubMed

The electrochemical behaviour of a synthetic boron-doped diamond thin film electrode (BDD) has been studied in acid media containing phenol using cyclic voltammetry and bulk electrolysis. The results have shown that in the potential region of water stability direct electron transfers can occur on BDD surface resulting in electrode fouling due to the formation of a polymeric film on its surface. During electrolysis in the potential region of oxygen evolution, complex oxidation reactions can take place due to electrogenerated hydroxyl radicals. Electrode fouling is inhibited under these conditions. Depending on the experimental conditions, the electrogenerated hydroxyl radicals can lead to the combustion of phenol or to the selective oxidation of phenol to benzoquinone. The experimental results have also been compared to a theoretical model that permits the prediction of the evolution with time of phenol concentration, during its combustion, or during its selective oxidation to benzoquinone. PMID:12489265

Panizza, Marco; Michaud, Pierre-Alain; Iniesta, Jesus; Comninellis, Christos; Cerisola, Giacomo

2002-10-01

404

Electronic structure and optical property of 3 d transition metal doped (5,5) boron nitride nanotube  

NASA Astrophysics Data System (ADS)

The electronic structure and magnetic and optical properties of a 3 d transition metal M (M = V, Cr, Mn, Fe) doped (5,5) boron nitride (B19MN20) nanotube are investigated by using the first-principles projector augmented wave potential within density functional theory under the generalized gradient approximation. It is found that B19VN20 and B19MnN20 systems are ideal candidates for spintronic applications, and the B19CrN20 system seems to be a promising diluted magnetic semiconductor. The analyses of optical dielectric functions show that B19CrN20 exhibits a new main peak at about 0.3 eV, and thus may be utilized in fields that are associated with infrared technology, such as infrared detectors, infrared masers, and so on.

Wang, Su-Fang; Zhang, Yan; Zhang, Jian-Min; Xu, Ke-Wei; Ji, Vincent

2012-11-01

405

In vivo pH monitoring using boron doped diamond microelectrode and silver needles: application to stomach disorder diagnosis.  

PubMed

This study presents the in vivo electrochemical monitoring of pH using boron doped diamond (BDD) microelectrode and silver needles for potential application in medical diagnosis. Accurate calibration curve for pH determination were obtained through in vitro electrochemical measurements. The increase induced in stomach pH by treatment with pantoprazole was used to demonstrate that it is possible to monitor the pH in vivo using the simple and noninvasive system proposed herein. Using the results of the in vivo and in vitro experiments, a quantitative analysis of the increase in stomach pH is also presented. It is proposed that the catheter-free pH monitoring system presented in this study could be potentially employed in any biological environment. PMID:24247214

Fierro, Stéphane; Seishima, Ryo; Nagano, Osamu; Saya, Hideyuki; Einaga, Yasuaki

2013-01-01

406

Electrocatalytic and photocatalytic activity of Pt-TiO2 films on boron-doped diamond substrate  

NASA Astrophysics Data System (ADS)

In the present work boron-doped diamond (BDD) polycrystalline films were used as support for direct anodic deposition of hydrous titanium oxide, and continuous TiO2 coatings were obtained by appropriately adjusting the deposition charge. The photoelectrochemical activity of the TiO2/BDD electrodes was investigated and it was found that, in terms of charge carriers separation efficiency, conductive diamond is a much better support for TiO2, compared to traditional carbonaceous materials such as glassy carbon. Further electrochemical deposition of platinum particles on the oxide-coated conductive diamond enabled the formation of a composite with enhanced electrochemically active surface area. The electrocatalytic and photocatalytic properties of the Pt/TiO2/BDD electrodes thus obtained were also scrutinized and it appeared that these hybrid systems also exhibit promising features for methanol anodic oxidation.

Sp?taru, Tan?a; Marcu, Maria; Sp?taru, Nicolae

2013-03-01

407

Examination of the factors affecting the electrochemical performance of oxygen-terminated polycrystalline boron-doped diamond electrodes.  

PubMed

In order to produce polycrystalline oxygen-terminated boron-doped diamond (BDD) electrodes suitable for electroanalysis (i.e., widest solvent window, lowest capacitive currents, stable and reproducible current responses, and capable of demonstrating fast electron transfer) for outer sphere redox couples, the following factors must be considered. The material must contain enough boron that the electrode shows metal-like conductivity; electrical measurements demonstrate that this is achieved at [B] > 10(20) B atoms cm(-3). Even though BDD contains a lower density of states than a metal, it is not necessary to use extreme doping levels to achieve fast heterogeneous electron transfer (HET). An average [B] ~ 3 × 10(20) B atoms cm(-3) was found to be optimal; increasing [B] results in higher capacitive values and increases the likelihood of nondiamond carbon (NDC) incorporation. Hydrogen-termination causes a semiconducting BDD electrode to behave metal-like due to the additional surface conductivity hydrogen termination brings. Thus, unless [B] of the material is known, the electrical properties of the electrode may be incorrectly interpreted. Note, this layer (formed on a lapped electrode) is electrochemically unstable, an effect which is exacerbated at increased potentials. It is essential during growth that NDC is minimized as it acts to increase capacitive currents and decrease the solvent window. We found complete removal of NDC after growth using aggressive acid cleans, acid cycling, and diamond polishing impossible. Although hydrogen termination can mask the NDC signature in the solvent window and lower capacitive currents, this is not a practical procedure for improving sensitivity in electroanalysis. Finally, alumina polishing of lapped, NDC free, freestanding, BDD electrodes was found to be an effective way to produce well-defined, stable, and reproducible surfaces, which support fast (reversible) HET for Fe(CN)6(4-) electrolysis, the first time this has been reported at an oxygen-terminated surface. PMID:23790001

Hutton, Laura A; Iacobini, James G; Bitziou, Eleni; Channon, Robert B; Newton, Mark E; Macpherson, Julie V

2013-08-01

408

Low-Temperature Softening Due to Vacancy Orbital with ?8 Quartet Ground State in Boron-Doped Floating Zone Silicon  

NASA Astrophysics Data System (ADS)

We have carried out low-temperature ultrasonic measurements using shear-mode ultrasound to clarify the quantum state of a vacancy orbital in boron-doped silicon grown by the floating zone (FZ) method. The elastic constants (C11-C12)/2 and C44 of the transverse mode exhibit considerable softening below 2 and 5 K down to the base temperature of 30 mK, respectively. The elastic constant C44 measured by the three ultrasonic modes (kx,uy), (kz,ux), and (kx,uz) shows the different magnetic field dependences among the configurations under applied magnetic fields along the z-axis. The elastic softening and the magnetic field dependence of the elastic constants are accounted for by the quadrupole susceptibility based on the energy level scheme of the vacancy orbital with a ?8 quartet ground state and ?7 doublet excited state located at an energy of 1 K. The difference in C44 between the two ultrasonic modes (kz,ux) and (kx,uz) at fields along the z-axis indicates that the ?8 quartet ground state is slightly split by local strain in the silicon sample. The quantum state of the vacancy orbital is expected to be sensitive to strain because of the extremely large quadrupole-strain coupling energy of g?? 105 K due to the extensively spreading orbital radius of r? 1 nm. The differences in variation of the low-temperature softening and magnetic field dependence among eight samples cut out from different locations of the present boron-doped FZ silicon ingot evidence the inhomogeneous distribution of the vacancy concentration.

Baba, Shotaro; Akatsu, Mitsuhiro; Mitsumoto, Keisuke; Komatsu, Satoru; Horie, Kunihiko; Nemoto, Yuichi; Yamada-Kaneta, Hiroshi; Goto, Terutaka

2013-08-01

409

Magnetization Study of Sulfur-doped Graphitic Nano-platelets and Single Walled Carbon Nanotubes  

NASA Astrophysics Data System (ADS)

Recently we investigated the magnetic behavior of as-prepared and sulfur doped chemically exfoliated graphene nano-platelets (GNPs) and single walled carbon nanotubes (SWCNTs). The doping was achieved by annealing desired carbon nanostructures with 0, 1.0, 1.5 and 3 at% sulfur in an evacuated quartz tube at 1000 ^oC for 1 day, followed by multiple rinsing in alcohol and drying in vacuum to remove excess sulfur. The isothermal M vs. H as well as the temperature-dependent M vs. T measurements were obtained using a vibrating sample magnetometer. We found that sulfur doping drastically changes the magnetic behavior of the as-prepared samples (both SWCNTs and GNPs). The results of zero-field-cooling (ZFC) and field-cooling (FC) in M vs. T measurements indicated the existence of large amount of coupled super-paramagnetic domains, along with antiferromagnetic domains. The saturation magnetization decreased in S doped GNPs, while a contrasting trend was observed in S doped SWCNTs. The role of edge states and structural defects in carbon nanostructures in the observed magnetic properties will be discussed.

Zhu, J.; Oliveira, L.; Podila, R.; Neeleshwar, S.; Chen, Y. Y.; He, J.; Skove, M.; Rao, A. M.

2013-03-01

410

Investigation of film formation properties during electrochemical oxidation of serotonin (5-HT) at polycrystalline boron doped diamond.  

PubMed

The change in surface morphology of oxygen-terminated polycrystalline boron doped diamond (pBDD) during electrochemical oxidation of the neurotransmitter serotonin (5-HT), resulting in a corresponding deterioration of the current signal, is investigated for the first time using both high resolution ex situ and in situ microscopy under a range of different electrochemical conditions. In situ electrochemical-atomic force microscopy (EC-AFM) reveals the formation of a granular film over the surface, which grows faster at higher-doped regions of the electrode surface and increases in thickness with repetitive potential cycles. The film properties were investigated using both cyclic voltammetry, with a range of redox species varying in charge, and conducting-AFM. These studies reveal the film to be positively charged and electrically insulating. The extent to which the film forms during 5-HT oxidation could be significantly minimised using different electrochemical procedures, as verified by voltammetry and in situ EC-AFM. Finally, even after extensive film formation, the original current signal could be recovered simply by leaving the electrode at open circuit potential for a short period of time, highlighting the suitability of BDD electrodes for neurotransmitter detection. PMID:24060971

Patel, Anisha N; Unwin, Patrick R; Macpherson, Julie V

2013-11-01

411

Fabrication Route for the Production of Coplanar, Diamond Insulated, Boron Doped Diamond Macro- and Microelectrodes of any Geometry.  

PubMed

Highly doped, boron doped diamond (BDD) is an electrode material with great potential, but the fabrication of suitable electrodes in a variety of different geometries both at the macro- and microscale, with an insulating material that does not compromise the material properties of the BDD, presents technical challenges. In this Technical Note, a novel solution to this problem is presented, resulting in the fabrication of coplanar macro- and microscale BDD electrodes, insulated by insulating diamond, at the single and multiple, individually addressable level. Using a laser micromachining approach, the required electrode(s) geometry is machined into an insulating diamond substrate, followed by overgrowth of high quality polycrystalline BDD (pBDD) and polishing to reveal approximately nanometer roughness, coplanar all-diamond structures. Electrical contacting is possible using both top and bottom contacts, where the latter are defined using the laser to produce non-diamond-carbon (NDC) in the vicinity of the back side of the BDD. We present the fabrication of individually addressable ring, band, and disk electrodes with minimum, reproducible controlled dimensions of 50 ?m (limited only by the laser system employed). The pBDD grown into the insulating diamond recesses is shown to be free from NDC and possesses excellent electrochemical properties, in terms of extended solvent windows, electrochemical reversibility, and capacitance. PMID:24814161

Joseph, Maxim B; Bitziou, Eleni; Read, Tania L; Meng, Lingcong; Palmer, Nicola L; Mollart, Tim P; Newton, Mark E; Macpherson, Julie V

2014-06-01

412

Evidence for substitutional boron in doped single-walled carbon nanotubes  

SciTech Connect

Precise determination of acceptors in the laser ablation grown B doped single-walled carbon nanotubes (SWCNTs) has been elusive. Photoemission spectroscopy finds evidence for subpercent substitutional B in this material, which leads to superconductivity in thin film SWNT samples.

Ayala, P.; Pichler, T. [Faculty of Physics, University of Vienna, 1090 Wien (Austria); Reppert, J.; Rao, A. M. [Department of Physics and Astronomy and COMSET, Clemson University (United States); Grobosch, M.; Knupfer, M. [IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany)

2010-05-03

413

Electronic state studies of a mono-boron-doped giant heterofullerene  

Microsoft Academic Search

With the establishment of a succinct geometrical description of a giant fullerene (GF), a built-in golden ratio has been discovered. The geometrical description serves as a key start for electronic state studies on large scale fullerenes and also heterofullerenes. Utilizating an extended Su-Schrieffer-Heeger model we mainly investigate one-boron substitution in fullerenes Cn (n = 60, 180, 240, 420, 540, 720,

Ying Zou; Zhijian Wang; Wenzhou Li

1997-01-01

414

Boron nitride fullerene B36N36 doped with transition metal atoms: First-principles calculations  

Microsoft Academic Search

We perform first-principles calculations for the interaction of the transition metal atoms Fe, Co, and W, as well as the FeO molecule, with the boron nitride fullerene B36N36 . The stable structure of the atom-fullerene complexes may have the dopant atom either at the center of the cage or making covalent bonds with the fullerene wall, with similar total energies.

Ronaldo J. C. Batista; Mário S. C. Mazzoni; Helio Chacham

2007-01-01

415

The processing of monodisperse boron-doped SiO 2 particles  

Microsoft Academic Search

Two processing methods were developed to add B2O3 to monodispersed, spherical (0.4 µm in diameter) Si02 particles. In each case the average bulk concentration of 1.5 wt% B203 was added to the surface of the silica particles. In the first process B203 was added with a boron alkoxide, B(OC4H9)3, during the precipitation of monodispersed silica particles; in the second process

N. J. Jubb; H. K. Bowen

1987-01-01

416

Remarkably low turn-on field emission in undoped, nitrogen-doped, and boron-doped graphene  

NASA Astrophysics Data System (ADS)

Field emission studies have been carried out on undoped as well as N- and B-doped graphene samples prepared by arc-discharge method in a hydrogen atmosphere. These graphene samples exhibit very low turn-on fields. N-doped graphene shows the lowest turn-on field of 0.6 V/?m, corresponding to emission current density of 10 ?A/cm2. These characteristics are superior to the other types of nanomaterials reported in the literature. Furthermore, emission currents are stable over the period of more than 3 h for the graphene samples. The observed emission behavior has been explained on the basis of nanometric features of graphene and resonance tunneling phenomenon.

Palnitkar, U. A.; Kashid, Ranjit V.; More, Mahendra A.; Joag, Dilip S.; Panchakarla, L. S.; Rao, C. N. R.

2010-08-01

417

Structural and electronic properties of Li- and Cu-doped ?-rhombohedral boron constructed from icosahedral and truncated icosahedral clusters  

NASA Astrophysics Data System (ADS)

This study performs dc conductivity and static magnetic-susceptibility measurements on Li- and Cu-doped ?-rhombohedral boron (?-rhombohedral B), which is a unique polymorphic semiconducting (group III) material composed of B12 icosahedral clusters. dc conductivity results show a variable-range-hopping (VRH)-type temperature dependence with a typical localization length of about ~1 Å. In addition, the density of states (DOS) at the Fermi energy, which is calculated from fitted parameters of VRH conduction, was found to have a peak with respect to metal concentration, such that at the highest concentration (Li7.9B105 and Cu4.2B105), metal-doped ?-rhombohedral B appears to revert back to an insulator, instead of showing insulator-to-metal transition. Corresponding static magnetic-susceptibility results, however, show a contribution from Pauli paramagnetism in the temperature-independent component ?0, where a similar concentration dependence is shows to that in the DOS of VRH conduction. Based on these properties, we discuss the possibility of filling the intrinsic acceptor band, which originates from the uppermost molecular bonding orbital of the B12 icosahedral cluster that is split by the Jahn-Teller effect. ?-rhombohedral B's crystalline structure can also be viewed as a slightly distorted face-centered cubic (fcc) packing of B84 soccer-ball-shaped clusters covalently bound to each other and containing a relatively large number of large-size interstitial doping sites. This structure is considered to be topologically similar to that of fcc C60, although the bonding mechanisms of their clusters are different, and therefore we also describe the similarities and differences between them.

Matsuda, H.; Nakayama, T.; Kimura, K.; Murakami, Y.; Suematsu, H.; Kobayashi, M.; Higashi, I.

1995-08-01

418

Hollow shells of high surface area graphitic N-doped carbon composites nanocast using zeolite templates  

Microsoft Academic Search

Hollow shells of porous nitrogen-doped carbon materials with high surface area have been prepared using zeolite templates (zeolite ? or silicalite-I) and acetonitrile as carbon source via chemical vapour deposition (CVD) performed at between 800 and 1000°C. The nitrogen content varies between 3.0 and 7.9wt.% depending on the zeolite template and CVD temperature. The carbon materials generally retain the particle

Zhuxian Yang; Yongde Xia; Robert Mokaya

2005-01-01

419

Effective visible light-active boron and europium co-doped BiVO4 synthesized by sol-gel method for photodegradion of methyl orange.  

PubMed

Eu-B co-doped BiVO4 visible-light-driven photocatalysts have been synthesized using the sol-gel method. The resulting materials were characterized by a series of joint techniques, including XPS, XRD, SEM, BET, and UV-vis DRS analyses. Compared with BiVO4 and B-BiVO4 photocatalysts, the Eu-B-BiVO4 photocatalysts exhibited much higher photocatalytic activity for methyl orange (MO) degradation under visible light irradiation. The optimal Eu doping content is 0.8 mol%. It was revealed that boron and europium were doped into the lattice of BiVO4 and this led to more surface oxygen vacancies, high specific surface areas, small crystallite size, a narrower band gap and intense light absorbance in the visible region. The doped Eu(III) cations can help in the separation of photogenerated electrons. The synergistic effects of boron and europium in doped BiVO4 were the main reason for improving visible light photocatalytic activity. PMID:24076480

Wang, Min; Che, Yinsheng; Niu, Chao; Dang, Mingyan; Dong, Duo

2013-11-15

420

Radiation-induced junction formation behavior of boron-doped Czochralski and float zone silicon crystals under 3 MeV proton irradiation  

Microsoft Academic Search

A comparative study was performed on the junction formation behavior of boron-doped p-type Czochralski (Cz) and float zone (Fz) Si wafers, which differed mainly in interstitial oxygen concentration, upon 3 MeV proton irradiation with fluences of up to 2×1015 cm?2. The region around the projected range in both the Cz and Fz Si wafers converted its conduction type to n

M. D. Chun; D. Kim; J. Y. Huh

2003-01-01

421

Radiation-induced junction formation behavior of boron-doped Czochralski and float zone silicon crystals under 3 MeV proton irradiation  

Microsoft Academic Search

A comparative study was performed on the junction formation behavior of boron-doped p-type Czochralski (Cz) and float zone (Fz) Si wafers, which differed mainly in interstitial oxygen concentration, upon 3 MeV proton irradiation with fluences of up to 2×1015 cm-2. The region around the projected range in both the Cz and Fz Si wafers converted its conduction type to n

M. D. Chun; D. Kim; J. Y. Huh

2003-01-01

422

Environmental sensitivity and mechanical behavior of boron-doped Fe–45at.%Al intermetallic in the temperature range from 77 to 1000 K  

Microsoft Academic Search

The tensile properties and fracture behavior of a coarse-grained (grain size ?420 ?m) Fe–45at.%Al intermetallic doped with 0.05 at.% boron were examined at ambient temperature in air, argon and vacuum as well as in the 77–1000 K temperature range in liquid nitrogen, dry ice and air. Before testing the alloy was low temperature annealed (vacancy annealed) in order to remove

J. Bystrzycki; R. A. Varin

1999-01-01

423

Degradation of Acid Orange 7 by electrochemically generated •OH radicals in acidic aqueous medium using a boron-doped diamond or platinum anode: A mechanistic study  

Microsoft Academic Search

A comparative study of the degradation of Acid Orange 7 (AO 7) aqueous solutions in acidic medium of pH 3.0 by electro-Fenton process using Pt or boron-doped diamond (BDD) anode was reported. The oxidative degradation of AO 7 by electrochemically generated hydroxyl radicals follows a pseudo-first order kinetic with a similar rate constant with BDD or Pt anode. The absolute

Samiha Hammami; Nizar Bellakhal; Nihal Oturan; Mehmet A. Oturan; Mohamed Dachraoui

2008-01-01

424

Is the boron-doped diamond electrode a suitable substitute for mercury in pesticide analyses? A comparative study of 4-nitrophenol quantification in pure and natural waters  

Microsoft Academic Search

A comparison between the analytical performance of a hanging mercury drop electrode (HMDE) and a boron-doped diamond (BDD) electrode for the quantification of 4-nitrophenol (4-NP) in spiked pure and natural waters is reported in this work. Square wave voltammetry (SWV) was chosen as the electroanalytical technique and Britton–Robinson buffer as the electrolyte. For the reduction process, the quantification limits varied

Valber A. Pedrosa; Lucia Codognoto; Sergio A. S. Machado; Luis A. Avaca

2004-01-01

425

Morphological and microstructural stability of boron-doped diamond thin film electrodes in an acidic chloride medium at high anodic current densities  

Microsoft Academic Search

Boron-doped diamond thin films have been examined before and after high-current-density electrolysis to investigate the morphological and microstructural stability of this new electrode material. The diamond thin films were used to generate chlorine from a solution of 1.0 M HNOâ + 2.0 M NaCl at current densities of 0.05 and 0.5 A\\/cm² for times up to 20 h. Comparative studies

Qingyun Chen; M. C. Granger; T. E. Lister; G. M. Swain

1997-01-01

426

Rotating ring–disk electrode studies of the oxidation of p-methoxyphenol and hydroquinone at boron-doped diamond electrodes  

Microsoft Academic Search

The stepwise electrochemical oxidation of p-methoxyphenol and hydroquinone at boron-doped diamond (BDD) electrodes was investigated in perchloric acid media using rotating ring–disk electrode (RRDE) and hydrodynamic modulation techniques. Initial oxidation of these compounds to p-benzoquinone at the disk may be confirmed by reduction of the quinone at the ring electrode. Further oxidation, ultimately to CO2, can be followed by the

David Sopchak; Barry Miller; Yitzhak Avyigal; Rafi Kalish

2002-01-01

427

Mineralization of clofibric acid by electrochemical advanced oxidation processes using a boron-doped diamond anode and Fe 2+ and UVA light as catalysts  

Microsoft Academic Search

This work shows that aqueous solutions of clofibric acid (2-(4-chlorophenoxy)-2-methylpropionic acid), the bioactive metabolite of various lipid-regulating drugs, up to saturation at pH 3.0 are efficiently and completely degraded by electrochemical advanced oxidation processes such as electro-Fenton and photoelectro-Fenton with Fe2+ and UVA light as catalysts using an undivided electrolytic cell with a boron-doped diamond (BDD) anode and an O2-diffusion

Ignasi Sirés; Francesc Centellas; José Antonio Garrido; Rosa María Rodríguez; Conchita Arias; Pere-Lluís Cabot; Enric Brillas

2007-01-01

428

Long period gratings and rocking filters written with a CO 2 laser in highly-birefringent boron-doped photonic crystal fibers for sensing applications  

NASA Astrophysics Data System (ADS)

In this work, we demonstrate the possibility of fabricating short-length long-period gratings and rocking filters in highly birefringent Photonic Crystal Fiber using a CO 2 laser. In our experiments both kinds of gratings were made in the same Boron doped highly birefringent PCF using similar exposure parameters. We also present the sensing capabilities of both fabricated gratings to temperature, strain and hydrostatic pressure by interrogation of the wavelength shifts at different resonances.

Carvalho, J. P.; Anuszkiewicz, A.; Statkiewicz-Barabach, G.; Baptista, J. M.; Frazão, O.; Mergo, P.; Santos, J. L.; Urbanczyk, W.

2012-02-01

429

Medium-gain erbium doped fiber amplifier ring laser passively mode-locked by graphite nano-powder adhered thin PVA film  

NASA Astrophysics Data System (ADS)

A direct brushing process of graphite nano-powder adhered on the single-mode fiber end-face with the use of an ultrathin PVA film is demonstrated, such a graphite nano-powder adhered ultra-thin PVA film is introduced to passively mode-lock a medium-gain Erbium-doped fiber laser (EDFL). The structural property of the graphite nano-powder is investigated by Raman spectroscopy. Numerous structural defects induced when abrading the graphite into nano-powder are found to broaden the 2D band Raman scattered signal and attenuate its peak intensity. The graphite nano-powders exhibit the featureless transmittance to show the potential as being a broadband tuning saturable absorber. In addition, the modulation depth of 0.43 is comparable with the graphene saturable absorber. The central wavelength of the passively mode-locked medium-gain EDFL is at 1561.2 nm with the full width at half maximum (FHWM) of 1.62 nm, and the pulsewidth is 1.58 ps. Under the limited intra-cavity power of 18 dBm, a nearly transform-limited passively mode-locking EDFL with TBP of 0.32 is generated.

Lin, Yung-Hsiang; Lin, Gong-Ru

2012-05-01

430

Studies on distribution of element contents in transient layer at interface between boron-doped diamond film electrode and tantalum substrate  

NASA Astrophysics Data System (ADS)

The boron-doped diamond film (BDD) grown on tantalum (Ta) substrate as an electrode (BDD/Ta) was prepared by hot filament chemical vapor deposition method. The experimental results demonstrated that our BDD/Ta had high current efficiency, strong ability to degrade wastewater, good corrosion stability and long lifetime. These excellent characteristics of BDD/Ta have been explained in terms of Rutherford backscattering (RBS) experiments. RBS investigation revealed that the continuous transient layer at the interface between boron-doped diamond film and Ta-substrate was formed and the microstructure of the continuous transient layer given by the continuous distribution of all element contents at the interface was obtained. The thicknesses of boron-doped diamond film and the continuous transient layer were about equal to 8000 × 10 15 atoms/cm 2 and 5800 × 10 15 atoms/cm 2, respectively. The formation of the continuous transient layer at the interface can eliminate the mismatch of thermal expansion coefficients (TEC) at the interface and only lead to the slow change of TEC because of the continuous distribution of element contents of the film and substrate in the transient layer at the interface. Thus, there is no residual stress to concentrate on the interface and the stress-corrosion delamination of the film disappears. Therefore, the corrosion stability and lifetime of BDD/Ta increase and last well, that have been verified by X-ray diffraction (XRD) experiments.

Liang, Jiachang; Gao, Chengyao; Zhang, Liping; Jiang, Lihui; Yang, Zhengquan; Wang, Zhiping; Ji, Chaohui; Le, Xiaoyun; Rong, Cuihua; Zhang, Jian

2011-05-01

431

A new assisted molecular cycloaddition on boron doped silicon surfaces: a predictive DFT-D study.  

PubMed

In the framework of the Density Functional Theory (DFT-D), we investigate the phthalocyanine (H2Pc) molecule adsorption on SiC(0001)3 × 3 and Si(111)?3 × ?3R30°-B (SiB) surfaces, and particularly compare the involved molecular adsorptions. In the H2Pc-SiC(0001)3 × 3 system, the molecular adsorption can be ascribed to a [10+2] cycloaddition. The H2Pc-SiB system is considered in three cases: defectless SiB surface (denoted SiB-0D) and SiB surfaces presenting one or two boron defects (denoted SiB-1D and SiB-2D respectively). The SiB-0D surface is passivated by a charge transfer from the Si adatoms to the boron atoms and therefore no chemical bond between the molecule and the substrate is observed. A similar molecular adsorption as already evidenced in the H2Pc-SiC(0001)3 × 3 system is involved in the SiB-2D case. In the case of the SiB-1D surface, two Si-N bonds (Si1-N1 and Si2-N2) are observed. One of them, Si1-N1, is nearly similar to that found in the H2Pc-SiB-2D system, but the Si2-N2 bond is unexpected. The Bader charge analysis suggests that, in the presence of the H2Pc molecule, the boron atoms behave like an electron reservoir whose availability varies following the involved molecular adsorption process. In the SiB-1D case, charges are transferred from the substrate to the molecule, allowing the Si2-N2 bond formation. Such a kind of molecular adsorption, not yet observed, could be designed by "assisted pseudo cycloaddition". PMID:24817040

Boukari, Khaoula; Duverger, Eric; Stauffer, Louise; Sonnet, Philippe

2014-06-28

432

Layered structure of anodic SiO{sub 2} films doped with phosphorus or boron  

SciTech Connect

It is shown that anodic silicon oxide films deposited by reanodization (repeated anodic oxidation) of p- and n-type silicon in phosphate (1.5 M H{sub 3}PO{sub 4}), borate (1.5 M H{sub 3}BO{sub 3}), and nitrate (0.04 M NH{sub 4}NO{sub 3}) electrolytes based on tetrahydrofurfuryl alcohol have a three- or four-layer structure both before and after high-temperature annealing. It is assumed that this circumstance accounts for the nonuniform distribution of phosphorus and boron across the thickness of anodic SiO{sub 2}.

Mileshko, L. P., E-mail: mil@fib.tsure.ru [Southern Federal University, Technological Institute (Russian Federation)

2009-12-15

433

Ion blistering of boron-doped silicon: The critical role of defect passivation  

SciTech Connect

The microscopic mechanism of hydrogen ion blistering of silicon was investigated using Raman scattering spectroscopy and thermal desorption spectrometry. The data in B-doped Si({approx}10{sup -3}/{omega} cm) are particularly worth noting, since B doping at this level strongly reduces both the ion dose and the thermal budget required for blistering. In that case the Si-H stretch mode is found to be shifted markedly towards higher frequencies characteristic of highly passivated vacancies and internal surfaces. It is deduced that the degree of defect passivation is a most critical factor for blistering.

Desrosiers, N.; Giguere, A.; Moutanabbir, O.; Terreault, B. [INRS-EMT, Universite du Quebec, 1650 Boul. Lionel-Boulet, Varennes, Quebec J3X 1S2 (Canada)

2005-12-05

434

Effect of Polishing on the Friction Behaviors and Cutting Performance of Boron-Doped Diamond Films on WC-Co Inserts  

NASA Astrophysics Data System (ADS)

Boron doped (B-doped) diamond films are deposited onto WC-Co inserts by HFCVD with the mixture of acetone, trimethyl borate (C3H9BO3) and H2. The as-deposited B-doped diamond films are characterized with scanning electron microscope (SEM), X-ray diffraction (XRD) spectroscopy, Raman spectroscopy, 3D surface topography based on white-light interferometry and Rockwell hardness tester. The effects of mechanical polishing on the friction behavior and cutting performance of B-doped diamond are evaluated by ball-on-plate type reciprocating tribometer and turning of aluminum alloy 7075 materials, respectively. For comparison, the same tests are also conducted for the bare WC-Co inserts with smooth surface. Friction tests suggest that the unpolished and polished B-doped diamond films possess relatively low fluctuation of friction coefficient than as-received bare WC-Co samples. The average stable friction coefficient for B-doped diamond films decreases apparently after mechanical polishing. The values for WC-Co sample, unpolished and polished B-doped diamond films are approximately 0.38, 0.25 and 0.11, respectively. The cutting results demonstrate that the low friction coefficient and high adhesive strength of B-doped diamond films play an essential role in the cutting performance enhancement of the WC-Co inserts. However, the mechanical polishing process may lower the adhesive strength of B-doped diamond films. Consequently, the polished B-doped diamond coated inserts show premature wear in the machining of adhesive aluminum alloy materials.

Wang, Liang; Shen, Bin; Sun, Fanghong; Zhang, Zhiming

2014-04-01

435

Comparative study of oxidation ability between boron-doped diamond (BDD) and lead oxide (PbO2) electrodes  

NASA Astrophysics Data System (ADS)

The electrochemical oxidation capabilities of two high-performance electrodes, the boron-doped diamond film on Ti (Ti/BDD) and the lead oxide film on Ti (Ti/PbO2), were discussed. Hydroxyl radicals (·HO) generated on the electrode surface were detected by using p-nitrosodimethylaniline (RNO) as the trapping reagent. Electrochemical oxidation measurements, including the chemical oxygen demand (COD) removal and the current efficiency (CE), were carried out via the degradation of p-nitrophenol (PNP) under the galvanostatic condition. The results indicate that an indirect reaction, which is attributed to free hydroxyl radicals with high activation, conducts on the Ti/BDD electrode, while the absorbed hydroxyl radicals generated at the Ti/PbO2 surface results in low degradation efficiency. Due to quick mineralization which combusts PNP to CO2 and H2O absolutely by the active hydroxyl radical directly, the CE obtained on the Ti/BDD electrode is much higher than that on the Ti/PbO2 electrode, notwithstanding the number of hydroxyl radicals produced on PbO2 is higher than that on the BDD surface.

Wei, Jun-Jun; Zhu, Xiu-Ping; Lü, Fan-Xiu; Ni, Jin-Ren

2011-10-01

436

Trace voltammetric detection of serotonin at carbon electrodes: comparison of glassy carbon, boron doped diamond and carbon nanotube network electrodes.  

PubMed

The characteristics of three different carbon electrodes, glassy carbon (GC), oxygen-terminated polycrystalline boron-doped diamond (pBDD) and "pristine" carbon nanotube networks (CNTN) as voltammetric sensors for detection of the neurotransmitter serotonin have been investigated. For each electrode, detection sensitivity was determined using cyclic voltammetry (CV), a technique often used to provide information on chemical identity in electrochemical assays. The CNTN electrodes were found to exhibit background current densities ca. two orders of magnitude smaller than the GC electrode and ca. twenty times smaller than pBDD, as a consequence of their "pristine" low capacitance and low surface coverage. This was a major factor in determining serotonin detection limits from CV, of 10 nM for the CNTN electrode, 500 nM for pBDD and 2 microM for GC. The two most sensitive electrodes (CNTN and pBDD) were further investigated in terms of resistance to electrode fouling. CV analysis showed that fouling was less on the pBDD electrode compared to the CNTN and, furthermore, for the case of pBDD could be significantly minimised by careful selection of the CV potential limits, in particular by scanning the electrode potential to suitably cathodic values after oxidation of the serotonin. PMID:20689900

Güell, Aleix G; Meadows, Katherine E; Unwin, Patrick R; Macpherson, Julie V

2010-09-14

437

The analysis of estrogenic compounds by flow injection analysis with amperometric detection using a boron-doped diamond electrode.  

PubMed

We report on the use of flow injection analysis with amperometric detection (FIA-EC) to evaluate the potential of using diamond electrodes for the analysis of three estrogenic compounds: estrone, 17-?-estradiol, and estriol. Amperometric detection was performed using a cathodically pretreated boron-doped diamond electrode that offered low background current, relatively low limits of detection, and good response reproducibility and stability. For all three compounds, response linearity was observed over the concentration range tested, 0.10 to 3.0?mol L(-1), the sensitivity was ca. 10mA L mol(-1), and the minimum concentration detection (S/N?3) was 0.10?mol L(-1) (~27?g L(-1)). The response variability with multiple injections was ca. 10% (RSD) over 20 injections. For estrone, the oxidation reaction on diamond does not proceed through an adsorbed state like it does on glassy carbon. After an initial current attenuation, the diamond electrode exhibited a stable response (oxidation current) for 3 days of continuous use, indicative of minimal surface contamination or fouling by reaction intermediates and products. The method for estrone was assessed using spiked city tap and local river water. Estrone recoveries in spiked city and river water samples presented standard deviations of less than 10%. In summary, the FIA-EC method with a diamond electrode enables sensitive, reproducible, stable, quick, and inexpensive determination of estrogenic compounds in water samples. PMID:24881529

Brocenschi, Ricardo F; Rocha-Filho, Romeu C; Duran, Boris; Swain, Greg M

2014-08-01

438

Determination of vanillin in commercial food product by adsorptive stripping voltammetry using a boron-doped diamond electrode.  

PubMed

A method for the determination of food additive vanillin was developed by adsorptive stripping voltammetry. Its determination was carried out at the anodically pre-treated boron-doped diamond electrode in aqueous solutions. Using square-wave stripping mode, the compound yielded a well-defined voltammetric response in phosphate buffer, pH 2.5 at +1.14 V (vs. Ag/AgCl) (a pre-concentration step being carried out at open-circuit condition for 60s). A linear calibration graph was obtained in the concentration range of 0.5-15.0 ?g mL(-1) (3.3×10(-6)-9.8×10(-5) mol L(-1)) with a detection limit of 0.024 ?g mL(-1) (1.6×10(-7) mol L(-1)). As an example, the practical applicability of the proposed method was tested for the determination of this flavouring agent in commercial pudding powder of Keshkule (Turkish milk pudding with almond flour). PMID:23870896

Yard?m, Yavuz; Gülcan, Mehmet; ?entürk, Zühre

2013-12-01

439

Electrochemical analysis of chloramphenicol using boron-doped diamond electrode applied to a flow-injection system.  

PubMed

The electrochemical properties of chloramphenicol at a boron-doped diamond thin-film (BDD) electrode were studied using cyclic voltammetry. The highest current response of chloramphenicol was obtained with phosphate buffer, pH 6 (0.1 M) in 1% ethanol. The relationship between the concentration of chloramphenicol and the current response was linear over the range of 0.1-10 mM (R2=0.9990). The amount of chloramphenicol was analyzed by flow-injection analysis. A thin-layer flow cell equipped with a BDD electrode was used as an amperometric detector, and experiments were carried out at -0.7 V (vs. Ag/AgCl). The linear relationship between the current response and the concentration of chloramphenicol in the range of 0.1-50 microM (R2=0.9948) and the limit of detection of 0.03 microM (S/N=3) were obtained. This method has been successfully applied to the determination of chloramphenicol in sterile eye drops and milk sample by the standard addition method. The average recoveries of chloramphenicol in eye drops were 98.0%, and the average recoveries of chloramphenicol from spiked milk were 93.9-103%. PMID:18403841

Chuanuwatanakul, Suchada; Chailapakul, Orawon; Motomizu, Shoji

2008-04-01

440

Simultaneous detection of monoamine and purine molecules using high-performance liquid chromatography with a boron-doped diamond electrode.  

PubMed

A recently available boron-doped diamond (BDD) working electrode has been developed for use with high-performance liquid chromatography (HPLC) to aid in the detection of molecules with high redox potentials. In this work, we developed a method using a commercially available BDD working electrode for detecting neurotransmitters from two different families with large oxidation potential differences, namely, dopamine (DA) and adenosine (Ado). Hydrodynamic voltammograms were constructed for DA and Ado, and the optimal potentials for the detection of DA and Ado were determined to be +740 and +1200 mV versus a palladium reference electrode, respectively. A working potential of +840 mV was chosen, and the detection range achieved with the BDD electrode for DA and Ado was from low nanomolar to high millimolar levels. To determine the practical function of the BDD electrode, tissue content was analyzed for seven monoamine and two purine molecules, which were resolved in a single run in less than 28 min. Our results demonstrate that the BDD electrode is sensitive and robust enough to detect monoamine and purine molecules from frontal cortex and striatal mouse samples. Using a BDD electrode opens the possibility of exploring multiple classes of neurotransmitters in a single run using electrochemical detection to probe their interactions. PMID:23815757

Birbeck, Johnna A; Mathews, Tiffany A

2013-08-01

441

Secondary electron emission from boron-doped diamond under ion impact: Applications in single-ion detection  

SciTech Connect

The secondary electron emission from a 2 {mu}m thick boron-doped diamond film under ion (4.6{endash}7.7 MeV He{sup +})impact is reported. The yield under ions impact is found to be remarkably high, stable over a period of many months, and independent of which side of the film (i.e., growth or substrate side) is exposed to the ion flux. By taking advantage of the high secondary-electron yield, the passage of each ion through the film could be detected with an efficiency of close to 100{percent}, which to the best of our knowledge is the highest efficiency recorded to date for any thin-film window. This finding has an immediate application in single-ion irradiation systems where a thin vacuum window is required to allow extraction of an ion beam from the vacuum into air and at the same time offer 100{percent} efficiency for the detection of the passage of the ion through the window. {copyright} {ital 1997 American Institute of Physics.}

Kamiya, T.; Cholewa, M.; Saint, A.; Prawer, S.; Legge, G.J. [School of Physics, The University of Melbourne, Micro Analytical Research Centre, Parkville, Victoria 3052 (Australia)] [School of Physics, The University of Melbourne, Micro Analytical Research Centre, Parkville, Victoria 3052 (Australia); Butler, J.E. [Gas/Surface Dynamics Section, Code 6174, Naval Research Laboratory, Washington, DC 20375 (United States)] [Gas/Surface Dynamics Section, Code 6174, Naval Research Laboratory, Washington, DC 20375 (United States); Vestyck, D.J. , Jr. [Geo-Centers, Inc., Fort Washington, Maryland 20744 (United States)] [Geo-Centers, Inc., Fort Washington, Maryland 20744 (United States)

1997-09-01

442

Determination of 1-hydroxypyrene in human urine by HPLC with electrochemical detection at a boron-doped diamond film electrode.  

PubMed

A high-performance liquid chromatographic method with electrochemical detection (HPLC-ED) at a boron-doped diamond film electrode with preliminary separation and preconcentration by solid-phase extraction (SPE) has been developed for the determination of 1-hydroxypyrene (1-HP) in human urine. 1-HP is among the most widely used biomarkers of exposure to polycyclic aromatic hydrocarbons. Optimal HPLC-ED conditions have been found: mobile phase methanol-0.05 mol L(-1) phosphate buffer pH 5.0 (80:20, v/v), detection potential +1,000 mV versus Ag/AgCl (3 mol L(-1) KCl), and flow rate 0.8 mL min(-1). For SPE, LiChrolut(®) RP-18 E cartridges were used. The extraction yield was (87.0 ± 5.8)% (n = 5). The concentration dependence of 1-HP was measured in the concentration range from 0.01 to 10 ?mol L(-1) (2.18-2,180 ?g L(-1)) using methanolic solutions resulting from the SPE pretreatment of spiked human urine samples. The limit of detection (signal-to-noise ratio 3) and the limit of quantification (signal-to-noise ratio 10) of the biomarker were 0.013 ?mol L(-1) (2.84 ?g L(-1)) and 0.043 ?mol L(-1) (9.39 ?g L(-1)), respectively, which is sufficient for its determination in the urine of persons exposed to polycyclic aromatic hydrocarbons. PMID:22695501

Yosypchuk, Oksana; Barek, Ji?í; Vysko?il, Vlastimil

2012-08-01

443

Facile electrocatalytic redox of hemoglobin by flower-like gold nanoparticles on boron-doped diamond surface.  

PubMed

The flower-like gold nanoparticles together with spherical and convex polyhedron gold nanoparticles were fabricated on boron-doped diamond (BDD) surface by one-step and simple electrochemical method through easily controlling the applied potential and the concentration of HAuCl(4). The recorded X-ray diffraction (XRD) patterns confirmed that these three shapes of gold nanoparticles were dominated by different crystal facets. The cyclic voltammetric results indicated that the morphology of gold nanoparticles plays big role in their electrochemical behaviors. The direct electrochemistry of hemoglobin (Hb) was realized on all the three different shapes of nanogold-attached BDD surface without the aid of any electron mediator. In pH 4.5 acetate buffer solutions (ABS), Hb showed a pair of well defined and quasi-reversible redox peaks. However, the results obtained demonstrated that the redox peak potential, the average surface concentration of electroactive heme, and the electron transfer rates of Hb are greatly dependent upon the surface morphology of gold nanoparticles. The electron transfer rate constant of hemoglobin over flower-like nanogold/BDD electrode was more than two times higher than that over spherical and convex polyhedron nanogold. The observed differences may be ascribed to the difference in gold particle characteristics including surface roughness, exposed surface area, and crystal structure. PMID:18805070

Li, Mingfang; Zhao, Guohua; Geng, Rong; Hu, Huikang

2008-11-01

444

Experimental Approach to Controllably Vary Protein Oxidation While Minimizing Electrode Adsorption for Boron-Doped Diamond Electrochemical Surface Mapping Applications  

SciTech Connect

Oxidative protein surface mapping has become a powerful approach for measuring the solvent accessibility of folded protein structures. A variety of techniques exist for generating the key reagent hydroxyl radicals for these measurements; however, many of these approaches require use of radioactive sources or caustic oxidizing chemicals. The purpose of this research was to evaluate and optimize the use of boron-doped diamond (BDD) electrochemistry as a highly accessible tool for producing hydroxyl radicals as a means to induce a controllable level of oxidation on a range of intact proteins. These experiments utilize a relatively high flow rates to reduce protein residence time inside the electrochemical flow chamber, along with a unique cell activation approach to improve control over the intact protein oxidation yield. Studies were conducted to evaluate the level of protein adsorption onto the electrode surface. This report demonstrates a robust protocol for the use of BDD electrochemistry and high performance LC-MS/MS as a high-throughput experimental pipeline for probing higher order protein structure, and illustrates how it is complementary to predictive computational modeling efforts.

McClintock, Carlee [ORNL; Hettich, Robert {Bob} L [ORNL

2013-01-01

445

Electrophoretic analysis of biomarkers using capillary modification with gold nanoparticles embedded in a polycation and boron doped diamond electrode.  

PubMed

Field-amplified sample stacking using a fused silica capillary coated with gold nanoparticles (AuNPs) embedded in poly(diallyl dimethylammonium) chloride (PDDA) has been investigated for the electrophoretic separation of indoxyl sulfate, homovanillic acid (HVA), and vanillylmandelic acid (VMA). AuNPs (27 nm) exhibit ionic and hydrophobic interactions, as well as hydrogen bonding with the PDDA network to form a stable layer on the internal wall of the capillary. This approach reverses electro-osmotic flow allowing for fast migration of the analytes while retarding other endogenous compounds including ascorbic acid, uric acid, catecholamines, and indoleamines. Notably, the two closely related biomarkers of clinical significance, HVA and VMA, displayed differential interaction with PDDA-AuNPs which enabled the separation of this pair. The detection limit of the three analytes obtained by using a boron doped diamond electrode was approximately 75 nM, which was significantly below their normal physiological levels in biological fluids. This combined separation and detection scheme was applied to the direct analysis of these analytes and other interfering chemicals including uric and ascorbic acids in urine samples without off-line sample treatment or preconcentration. PMID:20704378

Zhou, Lin; Glennon, Jeremy D; Luong, John H T

2010-08-15

446

Voltammetric determination of penicillin V in pharmaceutical formulations and human urine using a boron-doped diamond electrode.  

PubMed

Simple, sensitive and selective differential pulse voltammetric method for determination of penicillin V on a bare (unmodified) boron-doped diamond electrode has been developed. Penicillin V provided highly reproducible and well-defined irreversible oxidation peak at very positive potential of +1.6V (vs. Ag/AgCl). The optimum experimental conditions for oxidation of penicillin V were achieved in acetate buffer solution (pH 4.0). The modulation amplitude of 0.1V, modulation time of 0.05s and scan rate of 0.05Vs(-1) were selected as optimum instrumental parameters for differential pulse voltammetry. Linear response of peak current on the concentration in the range from 0.5 to 40?M with coefficient of determination of 0.999, good repeatability (RSD of 1.5%) and detection limit of 0.25?M were observed without any chemical modifications and electrochemical surface pretreatment. The effect of possible interferents such as stearic acid, glucose, urea, uric acid and ascorbic acid appeared to be negligible which evidently proved the good selectivity of method. The practical analytical utility of proposed method was demonstrated by determination of penicillin V in pharmaceutical formulations (tablets) and human urine samples with satisfactory recoveries (from 98 to 101% for tablets and 97 to 103% for human urine). PMID:22763423

Svorc, Lubomír; Sochr, Jozef; Rievaj, Miroslav; Tom?ík, Peter; Bustin, Dušan

2012-12-01

447

Square-wave voltammetric determination of bezafibrate in pharmaceutical formulations using a cathodically pretreated boron-doped diamond electrode.  

PubMed

The determination of bezafibrate (BZF) using square-wave voltammetry (SWV) and a cathodically pretreated boron-doped diamond electrode is proposed. Cyclic voltammetry results showed one irreversible oxidation peak for BZF at 1.20 V (vs. Ag/AgCl (3.0 mol L(-1) KCl)) in a 0.04 mol L(-1) Britton-Robinson (BR) buffer solution (pH 2.0). Under optimized SWV conditions, a linear analytical curve is obtained for the BZF concentration range 0.10-9.1 ?mol L(-1) in the BR buffer solution (pH 2.0), with a detection limit of 0.098 ?mol L(-1). The obtained recoveries range from 93.4 to 108%. The proposed novel method was successfully applied in the determination of the BZF content in several pharmaceutical formulations (tablets) and the results are in close agreement (at a 95% confidence level) with those obtained using a comparative spectrophotometric method. PMID:23200378

Ardila, Jorge Armando; Sartori, Elen Romão; Rocha-Filho, Romeu C; Fatibello-Filho, Orlando

2013-01-15