The direct electron transfer of hemoglobin at the PAMAM-MWNTs-AuNPs composite film modified glassy carbon electrode was studied. In a phosphate buffer solution（PBS, pH=7.0）, the formal potential（E^0） of Hb was -0....The direct electron transfer of hemoglobin at the PAMAM-MWNTs-AuNPs composite film modified glassy carbon electrode was studied. In a phosphate buffer solution（PBS, pH=7.0）, the formal potential（E^0） of Hb was -0.105 V versus SCE, the electron transfer rate constant was 4.66 s-1. E^0＇ of Hb at the modified electrode was linearly varied in a pH range of 5.0-8.0 with a slope of-49.2 mV/pH. The Hb/PAMAM-MWNTs-AuNPs/GCE gave an excellent electrocatalytic response to the reduction of hydrogen peroxide. The catalytic current increased linearly with H2O2 concentration in a range of 1.0× 10^-6 to 2.2× 10^-3 mol/L. The detection limit was 2.0× 10^-7 mol/L at a signal to noise ratio of 3. The Michaelis-Menten constant（Km^app） was 2.95 mmol/L.展开更多
Au-Pt/SnO2/GC composite electrode was prepared by self-assembling Au-Pt nanoparticles on SnO2 film, which was deposited on actived glassy carbon （GC）. Atomic force microscopy （AFM） and scanning electron microscopy...Au-Pt/SnO2/GC composite electrode was prepared by self-assembling Au-Pt nanoparticles on SnO2 film, which was deposited on actived glassy carbon （GC）. Atomic force microscopy （AFM） and scanning electron microscopy （SEM） images revealed that dense and uniform Au-Pt particles with 25-nm diameter were dispersed on SnO2 film. X-ray photoelectron spectroscopy （XPS） results proved that there was an interaction between Au-Pt nanoparticles and SnO2 support. Electrochemical experiments showed that Au-Pt/SnOz/GC composite electrode had a good electrocatalytic activity to the oxidation of methanol展开更多
Objective To study environment-friendly determination of azobenzene in trace amounts using β-cyclodextrin （β-CD）-modified Au electrode. Methods β-CD-modified Au electrode was fabricated with a two-step approach, ...Objective To study environment-friendly determination of azobenzene in trace amounts using β-cyclodextrin （β-CD）-modified Au electrode. Methods β-CD-modified Au electrode was fabricated with a two-step approach, and then a gold electrode modified with β-CD was used to detect azobenzene by employing Osteryoung square wave voltammetry. Results The modified electrode could detect azobenzene, showing a good linearity between the electrochemical current and concentration. Conclusion Although the electrochemical current is related with concentration, the detection limit is around 1 .0 ×10^-10 mol/L. This study may provide a new environment-friendly approach for monitoring water quality.展开更多
The electrochemical quartz crystal microbalance (EQCM) was applied to study the electrochemical behaviors of polycrystalline Au in sulfuric acid solution. The large mass change observed in the doublelayer region was a...The electrochemical quartz crystal microbalance (EQCM) was applied to study the electrochemical behaviors of polycrystalline Au in sulfuric acid solution. The large mass change observed in the doublelayer region was attributed to the partly discharged adsorption of sulfate anions with the co-adsorption of H2O. According to the observed EQCM frequency response, the formation mechanism of surface oxide was reasonably postulated, in which the roles of the adsorbed anions and the co-adsorbed H2O were particularly emphasized.展开更多
The electrochemical quartz crystal impedance system (EQCIS) has been used for the study of a partially immersed Au electrode in 0.2 mol/L NaClO4 aqueous solution. The influences of the immersed area and height of the ...The electrochemical quartz crystal impedance system (EQCIS) has been used for the study of a partially immersed Au electrode in 0.2 mol/L NaClO4 aqueous solution. The influences of the immersed area and height of the electrode on the EQCIS responses were evaluated, showing the highest response sensitivity to liquid loading at the center of the piezoelectric quartz crystal electrode. The increase in the immersed height of the Au electrode at oxygen reduction potentials during potential cycling was measured by this technique.展开更多
利用电化学、电学等手段研究利用浸渍-还原技术在Nafion膜上制备Au电极的方法,考查Au络合物浸渍时间、还原剂浓度、还原温度等因素对Au/Nafion电极性能的影响。研究发现:较长的浸渍时间、较低的还原剂浓度和较高的还原温度下所制备的电...利用电化学、电学等手段研究利用浸渍-还原技术在Nafion膜上制备Au电极的方法,考查Au络合物浸渍时间、还原剂浓度、还原温度等因素对Au/Nafion电极性能的影响。研究发现:较长的浸渍时间、较低的还原剂浓度和较高的还原温度下所制备的电极活性较好,同时以Na2SO3作为还原剂时,可得到表面Au颗粒均匀堆积的Au/Nafion复合电极。对比利用浸渍-还原技术制备的Pt/Nafion电极和浸渍-还原法制备的Au/Nafion电极在水-苯体系电化学加氢反应中的电极活性。结果表明:苯在阴极的加氢反应主要产物为环己烯和环己烷,且在高阴极过电势下主要生成环己烷;利用Au/Nafion电极实现苯在阴极的加氢还原反应总电流效率可达40%~90%(-1.6^-0.4V vs SCE),析氢副反应在Au/Nafion电极上得到较好抑制。展开更多
基金Supported by the National Natural Science Foundation of China(No.20605009)
文摘The direct electron transfer of hemoglobin at the PAMAM-MWNTs-AuNPs composite film modified glassy carbon electrode was studied. In a phosphate buffer solution（PBS, pH=7.0）, the formal potential（E^0） of Hb was -0.105 V versus SCE, the electron transfer rate constant was 4.66 s-1. E^0＇ of Hb at the modified electrode was linearly varied in a pH range of 5.0-8.0 with a slope of-49.2 mV/pH. The Hb/PAMAM-MWNTs-AuNPs/GCE gave an excellent electrocatalytic response to the reduction of hydrogen peroxide. The catalytic current increased linearly with H2O2 concentration in a range of 1.0× 10^-6 to 2.2× 10^-3 mol/L. The detection limit was 2.0× 10^-7 mol/L at a signal to noise ratio of 3. The Michaelis-Menten constant（Km^app） was 2.95 mmol/L.
基金supported by the High-Tech Research and Development Program of China (No. 2007AA03Z219)the Funding Project for Academic Human Resources Development in Institutions of Higher Learning under the Jurisdiction of Beijing Municipality, and the Beijing Natural Science Foundation (No. 207001)
文摘Au-Pt/SnO2/GC composite electrode was prepared by self-assembling Au-Pt nanoparticles on SnO2 film, which was deposited on actived glassy carbon （GC）. Atomic force microscopy （AFM） and scanning electron microscopy （SEM） images revealed that dense and uniform Au-Pt particles with 25-nm diameter were dispersed on SnO2 film. X-ray photoelectron spectroscopy （XPS） results proved that there was an interaction between Au-Pt nanoparticles and SnO2 support. Electrochemical experiments showed that Au-Pt/SnOz/GC composite electrode had a good electrocatalytic activity to the oxidation of methanol
基金supported by the National Natural Science Foundation of China (Project No. 60471005) Program for Changjiang Scholars and Innovative Research Team in University.
文摘Objective To study environment-friendly determination of azobenzene in trace amounts using β-cyclodextrin （β-CD）-modified Au electrode. Methods β-CD-modified Au electrode was fabricated with a two-step approach, and then a gold electrode modified with β-CD was used to detect azobenzene by employing Osteryoung square wave voltammetry. Results The modified electrode could detect azobenzene, showing a good linearity between the electrochemical current and concentration. Conclusion Although the electrochemical current is related with concentration, the detection limit is around 1 .0 ×10^-10 mol/L. This study may provide a new environment-friendly approach for monitoring water quality.
文摘The electrochemical quartz crystal microbalance (EQCM) was applied to study the electrochemical behaviors of polycrystalline Au in sulfuric acid solution. The large mass change observed in the doublelayer region was attributed to the partly discharged adsorption of sulfate anions with the co-adsorption of H2O. According to the observed EQCM frequency response, the formation mechanism of surface oxide was reasonably postulated, in which the roles of the adsorbed anions and the co-adsorbed H2O were particularly emphasized.
基金This work was supported by the National Natural Science Foundation of China the Science and Technology Foundation of Hunan P
文摘The electrochemical quartz crystal impedance system (EQCIS) has been used for the study of a partially immersed Au electrode in 0.2 mol/L NaClO4 aqueous solution. The influences of the immersed area and height of the electrode on the EQCIS responses were evaluated, showing the highest response sensitivity to liquid loading at the center of the piezoelectric quartz crystal electrode. The increase in the immersed height of the Au electrode at oxygen reduction potentials during potential cycling was measured by this technique.
文摘利用电化学、电学等手段研究利用浸渍-还原技术在Nafion膜上制备Au电极的方法,考查Au络合物浸渍时间、还原剂浓度、还原温度等因素对Au/Nafion电极性能的影响。研究发现:较长的浸渍时间、较低的还原剂浓度和较高的还原温度下所制备的电极活性较好,同时以Na2SO3作为还原剂时,可得到表面Au颗粒均匀堆积的Au/Nafion复合电极。对比利用浸渍-还原技术制备的Pt/Nafion电极和浸渍-还原法制备的Au/Nafion电极在水-苯体系电化学加氢反应中的电极活性。结果表明:苯在阴极的加氢反应主要产物为环己烯和环己烷,且在高阴极过电势下主要生成环己烷;利用Au/Nafion电极实现苯在阴极的加氢还原反应总电流效率可达40%~90%(-1.6^-0.4V vs SCE),析氢副反应在Au/Nafion电极上得到较好抑制。
