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Richard G. Compton - One of the best experts on this subject based on the ideXlab platform.
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the charge transfer kinetics of the oxidation of silver and nickel nanoparticles via particle electrode impact electrochemistry
Physical Chemistry Chemical Physics, 2012Co-Authors: Yige Zhou, Neil V. Rees, Baptiste Haddou, Richard G. ComptonAbstract:The Electro-Oxidation of silver and nickel nanoparticles in aqueous solution was studied via their collisions with a carbon electrode. The average charge passed per impact varies with electrode potential and was analysed to determine that AgNPs display an electrochemically fast (“reversible”) one-electron oxidation, whilst the NiNPs exhibit slow (“irreversible”) 2-electron kinetics. Kinetic parameters are reported.
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nanoparticle electrode impacts the oxidation of copper nanoparticles has slow kinetics
Physical Chemistry Chemical Physics, 2012Co-Authors: Baptiste Haddou, Neil V. Rees, Richard G. ComptonAbstract:The electrochemical oxidation of copper nanoparticles in aqueous solution was studied via their electrolysis upon impacting a carbon electrode held at a suitable anodic potential. The oxidations were found to be quantitative such that complete oxidation of the particle took place allowing their sizing. Experiments were performed in 1.0 M HNO3 and in 1.0 M HNO3–0.1 M KCl. In the former case a two electron oxidation to Cu2+ was seen at a formal potential of +0.11 V (vs. SCE). In the latter case two separate one-electron oxidations at −0.01 V and +0.26 V were seen. In addition, theoretical results were derived for the analysis of impact-charge vs. potential data for reversible and irreversible charge transfer kinetics for nanoparticle oxidation. This enabled the inference that overpotential is required for the oxidations and Butler–Volmer transfer coefficients to be determined. The latter are compared with literature data seen for macroscopic copper.
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marcus theory of outer sphere heterogeneous electron transfer reactions dependence of the standard electrochemical rate constant on the hydrodynamic radius from high precision measurements of the oxidation of anthracene and its derivatives in nonaque
Journal of the American Chemical Society, 2004Co-Authors: Antony D Clegg, Barry A Coles, Neil V. Rees, Oleksiy V Klymenko, Richard G. ComptonAbstract:The validity of Marcus theory for outer-sphere heterogeneous electron transfer for the Electro-Oxidation of a range of anthracene derivatives in alkyl cyanide solvents is investigated. The precision measurement of these fast electron transfers (k0 ≥ 1 cm s-1) is achieved by use of the high-speed channel electrode and, where necessary, fast-scan cyclic voltammetry. First, the solvent effect on the rate of electron transfer is studied by considering the first oxidation wave of 9,10-diphenylanthracene in the alkyl cyanide solvents: acetonitrile, propionitrile, butyronitrile, and valeronitrile. Second, the variation of k0 for a series of substituted anthracenes is investigated by analyzing the voltammetric response of the one-electron oxidations of 9-phenylanthracene, 9,10-dichloroanthracene, 9-chloroanthracene, 9,10-dicyanoanthracene, 9-cyanoanthracene, 9-nitroanthracene, 9,10-diphenylanthracene, and anthracene in acetonitrile. It is shown that the rate of electron transfer of a single compound in different...
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marcus theory of outer sphere heterogeneous electron transfer reactions dependence of the standard electrochemical rate constant on the hydrodynamic radius from high precision measurements of the oxidation of anthracene and its derivatives in nonaque
Journal of the American Chemical Society, 2004Co-Authors: Antony D Clegg, Barry A Coles, Neil V. Rees, Oleksiy V Klymenko, Richard G. ComptonAbstract:The validity of Marcus theory for outer-sphere heterogeneous electron transfer for the Electro-Oxidation of a range of anthracene derivatives in alkyl cyanide solvents is investigated. The precision measurement of these fast electron transfers (k(0) >or= 1 cm s(-1)) is achieved by use of the high-speed channel electrode and, where necessary, fast-scan cyclic voltammetry. First, the solvent effect on the rate of electron transfer is studied by considering the first oxidation wave of 9,10-diphenylanthracene in the alkyl cyanide solvents: acetonitrile, propionitrile, butyronitrile, and valeronitrile. Second, the variation of k(0) for a series of substituted anthracenes is investigated by analyzing the voltammetric response of the one-electron oxidations of 9-phenylanthracene, 9,10-dichloroanthracene, 9-chloroanthracene, 9,10-dicyanoanthracene, 9-cyanoanthracene, 9-nitroanthracene, 9,10-diphenylanthracene, and anthracene in acetonitrile. It is shown that the rate of electron transfer of a single compound in different alkyl cyanides is determined by the longitudinal dielectric relaxation properties of the solvent, while differences in rate between the substituted anthracenes in acetonitrile can be quantitatively rationalized by considering their relative hydrodynamic radii. This makes possible the accurate prediction of electron-transfer rates for a molecule by interpolation of rate constants known for related molecules.
Concepció Rovira - One of the best experts on this subject based on the ideXlab platform.
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the interplay of inverted redox potentials and aromaticity in the oxidized states of new π electron donors 9 1 3 dithiol 2 ylidene fluorene and 9 1 3 dithiol 2 ylidene thioxanthene derivatives
Chemistry: A European Journal, 2006Co-Authors: Samia Amriou, Dmitrii F. Perepichka, Enrique Ortí, Rafael Viruela, Changsheng Wang, Andrei S. Batsanov, Martin R Bryce, Jose Vidalgancedo, Concepció RoviraAbstract:Derivatives of 9-(1,3-dithiol- 2-ylidene)fluorene (9) and 9-(1,3-di- thiol-2-ylidene)thioxanthene (10) have been synthesised using Horner-Wads- worth-Emmons reactions of (1,3-di- thiol-2-yl)phosphonate reagents with fluorenone and thioxanthen-9-one. X- ray crystallography, solution electro- chemistry, optical spectroscopy, spec- troelectrochemistry and simultaneous electrochemistry and electron para- magnetic resonance (SEEPR), com- bined with theoretical calculations per- formed at the B3P86/6-31G** level, elucidate the interplay of the electronic and structural properties in these mole- cules. These compounds are strong two-electron donors, and the oxidation potentials depend on the electronic structure of the oxidised state. Two, single-electron oxidations (E ox E ox ) resulting in a single, two- electron oxidation process. The latter is due to the aromatic structure of the thioxanthenium cation (formed on the loss of a second electron), which stabil- ises the dication state (10 2 + ) compared with the radical cation. This contrasts with the nonaromatic structure of the fluorenium cation of system 9 .T he two-electron oxidation wave in the thioxanthene derivatives is split into two separate one-electron waves in the corresponding sulfoxide and sulfone derivatives 27-29 owing to destabilisa- tion of the dication state.
Dmitrii F. Perepichka - One of the best experts on this subject based on the ideXlab platform.
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the interplay of inverted redox potentials and aromaticity in the oxidized states of new π electron donors 9 1 3 dithiol 2 ylidene fluorene and 9 1 3 dithiol 2 ylidene thioxanthene derivatives
Chemistry: A European Journal, 2006Co-Authors: Samia Amriou, Dmitrii F. Perepichka, Enrique Ortí, Rafael Viruela, Changsheng Wang, Andrei S. Batsanov, Martin R Bryce, Jose Vidalgancedo, Concepció RoviraAbstract:Derivatives of 9-(1,3-dithiol- 2-ylidene)fluorene (9) and 9-(1,3-di- thiol-2-ylidene)thioxanthene (10) have been synthesised using Horner-Wads- worth-Emmons reactions of (1,3-di- thiol-2-yl)phosphonate reagents with fluorenone and thioxanthen-9-one. X- ray crystallography, solution electro- chemistry, optical spectroscopy, spec- troelectrochemistry and simultaneous electrochemistry and electron para- magnetic resonance (SEEPR), com- bined with theoretical calculations per- formed at the B3P86/6-31G** level, elucidate the interplay of the electronic and structural properties in these mole- cules. These compounds are strong two-electron donors, and the oxidation potentials depend on the electronic structure of the oxidised state. Two, single-electron oxidations (E ox E ox ) resulting in a single, two- electron oxidation process. The latter is due to the aromatic structure of the thioxanthenium cation (formed on the loss of a second electron), which stabil- ises the dication state (10 2 + ) compared with the radical cation. This contrasts with the nonaromatic structure of the fluorenium cation of system 9 .T he two-electron oxidation wave in the thioxanthene derivatives is split into two separate one-electron waves in the corresponding sulfoxide and sulfone derivatives 27-29 owing to destabilisa- tion of the dication state.
Neil V. Rees - One of the best experts on this subject based on the ideXlab platform.
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the charge transfer kinetics of the oxidation of silver and nickel nanoparticles via particle electrode impact electrochemistry
Physical Chemistry Chemical Physics, 2012Co-Authors: Yige Zhou, Neil V. Rees, Baptiste Haddou, Richard G. ComptonAbstract:The Electro-Oxidation of silver and nickel nanoparticles in aqueous solution was studied via their collisions with a carbon electrode. The average charge passed per impact varies with electrode potential and was analysed to determine that AgNPs display an electrochemically fast (“reversible”) one-electron oxidation, whilst the NiNPs exhibit slow (“irreversible”) 2-electron kinetics. Kinetic parameters are reported.
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nanoparticle electrode impacts the oxidation of copper nanoparticles has slow kinetics
Physical Chemistry Chemical Physics, 2012Co-Authors: Baptiste Haddou, Neil V. Rees, Richard G. ComptonAbstract:The electrochemical oxidation of copper nanoparticles in aqueous solution was studied via their electrolysis upon impacting a carbon electrode held at a suitable anodic potential. The oxidations were found to be quantitative such that complete oxidation of the particle took place allowing their sizing. Experiments were performed in 1.0 M HNO3 and in 1.0 M HNO3–0.1 M KCl. In the former case a two electron oxidation to Cu2+ was seen at a formal potential of +0.11 V (vs. SCE). In the latter case two separate one-electron oxidations at −0.01 V and +0.26 V were seen. In addition, theoretical results were derived for the analysis of impact-charge vs. potential data for reversible and irreversible charge transfer kinetics for nanoparticle oxidation. This enabled the inference that overpotential is required for the oxidations and Butler–Volmer transfer coefficients to be determined. The latter are compared with literature data seen for macroscopic copper.
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marcus theory of outer sphere heterogeneous electron transfer reactions dependence of the standard electrochemical rate constant on the hydrodynamic radius from high precision measurements of the oxidation of anthracene and its derivatives in nonaque
Journal of the American Chemical Society, 2004Co-Authors: Antony D Clegg, Barry A Coles, Neil V. Rees, Oleksiy V Klymenko, Richard G. ComptonAbstract:The validity of Marcus theory for outer-sphere heterogeneous electron transfer for the Electro-Oxidation of a range of anthracene derivatives in alkyl cyanide solvents is investigated. The precision measurement of these fast electron transfers (k0 ≥ 1 cm s-1) is achieved by use of the high-speed channel electrode and, where necessary, fast-scan cyclic voltammetry. First, the solvent effect on the rate of electron transfer is studied by considering the first oxidation wave of 9,10-diphenylanthracene in the alkyl cyanide solvents: acetonitrile, propionitrile, butyronitrile, and valeronitrile. Second, the variation of k0 for a series of substituted anthracenes is investigated by analyzing the voltammetric response of the one-electron oxidations of 9-phenylanthracene, 9,10-dichloroanthracene, 9-chloroanthracene, 9,10-dicyanoanthracene, 9-cyanoanthracene, 9-nitroanthracene, 9,10-diphenylanthracene, and anthracene in acetonitrile. It is shown that the rate of electron transfer of a single compound in different...
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marcus theory of outer sphere heterogeneous electron transfer reactions dependence of the standard electrochemical rate constant on the hydrodynamic radius from high precision measurements of the oxidation of anthracene and its derivatives in nonaque
Journal of the American Chemical Society, 2004Co-Authors: Antony D Clegg, Barry A Coles, Neil V. Rees, Oleksiy V Klymenko, Richard G. ComptonAbstract:The validity of Marcus theory for outer-sphere heterogeneous electron transfer for the Electro-Oxidation of a range of anthracene derivatives in alkyl cyanide solvents is investigated. The precision measurement of these fast electron transfers (k(0) >or= 1 cm s(-1)) is achieved by use of the high-speed channel electrode and, where necessary, fast-scan cyclic voltammetry. First, the solvent effect on the rate of electron transfer is studied by considering the first oxidation wave of 9,10-diphenylanthracene in the alkyl cyanide solvents: acetonitrile, propionitrile, butyronitrile, and valeronitrile. Second, the variation of k(0) for a series of substituted anthracenes is investigated by analyzing the voltammetric response of the one-electron oxidations of 9-phenylanthracene, 9,10-dichloroanthracene, 9-chloroanthracene, 9,10-dicyanoanthracene, 9-cyanoanthracene, 9-nitroanthracene, 9,10-diphenylanthracene, and anthracene in acetonitrile. It is shown that the rate of electron transfer of a single compound in different alkyl cyanides is determined by the longitudinal dielectric relaxation properties of the solvent, while differences in rate between the substituted anthracenes in acetonitrile can be quantitatively rationalized by considering their relative hydrodynamic radii. This makes possible the accurate prediction of electron-transfer rates for a molecule by interpolation of rate constants known for related molecules.
Suddhasatwa Basu - One of the best experts on this subject based on the ideXlab platform.
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performance studies of pd pt and pt pd au catalyst for electro oxidation of glucose in direct glucose fuel cell
International Journal of Hydrogen Energy, 2012Co-Authors: Debika Basu, Suddhasatwa BasuAbstract:Abstract Platinum is employed as anode catalyst for low temperature Electro-Oxidation of glucose in direct glucose fuel cell (DGFC), but it suffers from poisoning by intermediate oxidation products. In the present investigation, palladium and gold precursors are added with platinum precursor to form low metal loading (∼15–20% by wt.) carbon supported catalyst by NaBH4 reduction technique. The prepared PtPdAu/C (metal ratio 1:1:1) and PdPt/C (metal ratio 4:1) catalysts are tested in DGFC. The Physical characterization of electro-catalysts by scanning electron microscope, transmission electron microscope, energy dispersive X-ray, X-ray diffraction and thermo-gravimetric analysis confirms the formation of nano-sized metal particles on carbon substrate with two prominent homogeneous bi- or tri-metallic crystal phases for PtPdAu/C. The cyclic voltammetry studies carried out for glucose (0.05 M) oxidation in (0.5 M KOH) alkaline medium shows the metal catalysts can efficiently electro-oxidize glucose. The catalysts tested as anode in a batch type DGFC using commercial activated charcoal as cathode produced peak power density of 0.52 mW cm−2 for both PdPt/C and PtPdAu/C in 0.3 M glucose in 1 M KOH solution.
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synthesis and characterization of pt au c catalyst for glucose electro oxidation for the application in direct glucose fuel cell
International Journal of Hydrogen Energy, 2011Co-Authors: Debika Basu, Suddhasatwa BasuAbstract:Abstract To minimize the poisoning of Pt-catalyst in glucose Electro-Oxidation for direct glucose fuel cell, carbon supported low metal loaded platinum–gold (Pt–Au/C) catalyst (1:1) was synthesized by immobilizing metal sols on carbon. The physical characterization of Pt–Au/C, Pt/C and Au/C was carried out using transmission electron microscope (TEM), scanning electron microscope (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD) and thermo gravimetric analysis (TGA). SEM indicates the uniformity in loading of metals on Vulcan XC-72 carbon support, whereas TEM picture and XRD pattern confirm the formation of Pt–Au nanoparticles of less than 10 nm size. TGA shows the metal present in Pt–Au/C catalyst is 14.5% by wt. Electrochemical analysis such as cyclic voltammetry (CV) and chronoamperometry (CA) on Pt–Au/C and commercial Pt/C and Au/C (40 wt. % of metal) for glucose Electro-Oxidation in alkaline media shows that Pt–Au/C is capable of Electro-Oxidation of glucose at low potential as that of Pt/C catalyst and more active than Au/C catalyst. The poisoning rate of prepared Pt–Au/C (0.0046% s −1 ) is lower than that of Pt–Ru/C (0.0085% s −1 ) and Pt/C (0.011% s −1 ) catalysts. A batch cell operated using Pt–Au/C as anode and activated charcoal as cathode delivered 0.9 V OCV and 0.72 mW cm −2 peak power density at 0.2 M glucose in 1 M KOH solution.