The electrocatalytic oxidation of methanol was studied over Ni, Co and Cu binary or ternary alloys on graphite electrodes in a NaOH solution （0.1 mol/L）. The catalysts were prepared by cycling the graphite electrode...The electrocatalytic oxidation of methanol was studied over Ni, Co and Cu binary or ternary alloys on graphite electrodes in a NaOH solution （0.1 mol/L）. The catalysts were prepared by cycling the graphite electrode in solutions containing Ni, Cu and Co ions at cathodic potentials. The synergistic effects and catalytic activity of the modified electrodes were investigated by cyclic voltammetry （CV）, chronoamperometry CCA） and electrochemical impedance spectroscopy （EIS）. It was found that, in the presence of methanol, the modified Ni-based ternary alloy electrode （G/NiCuCo） exhibited a significantly higher response for methanol oxidation compared to the other samples. The anodic peak currents showed a linear dependency on the square root of the scan rate, which is a characteristic of a diffusion controlled process. During CA studies, the reaction exhibited Cottrellin behavior and the diffusion coefficient of methanol was determined to be 6.25× 10-6 cm2/s and the catalytic rate constant, K, for methanol oxidation was found to be 40×107 cm3/Cmol.s）. EIS was used to investigate the catalytic oxidation of methanol on the surface of the modified electrode.展开更多
Improving catalyst performance by studying the preparation parameters, material structures and analysis methods is important work for catalyst researchers. In this study, Cu-Pt nanocomposites with different metal rati...Improving catalyst performance by studying the preparation parameters, material structures and analysis methods is important work for catalyst researchers. In this study, Cu-Pt nanocomposites with different metal ratios were synthesized on MWCNTs using a polyol method. The structures and morphologies of the nano hybrid catalysts were analyzed by XRD and TEM. The XRD results indicate that Pt and Cu formed a bimetallic solid solution. The average diameters of the Pt and Cu-Pt nanoparticles on MWCNTs were between 3-10 nm and 5-15 nm, respectively. The electrocatalytic behavior of methanol oxidation reactions was investigated by cyclic voltammery （CV）. Cu（20%）/[Pt/MWCNTs（1：4）], which contained an optimal degree of solid solution, enhanced the methanol oxidation to the greatest degree.展开更多
Surfactant removal from the surface of platinum-based nanoparticles prepared using solution-based methods is a prerequisite to realize their high catalytic performance for electrochemical reactions. Herein, we report ...Surfactant removal from the surface of platinum-based nanoparticles prepared using solution-based methods is a prerequisite to realize their high catalytic performance for electrochemical reactions. Herein, we report an effective approach combining acetic acid refluxing with an electrochemical process for the removal of amine- or thiol-based capping agents from the surface of supported-platinum nanoparticles. This strategy involves surfactant protonation by refluxing the supported-platinum particles in acetic acid followed by surfactant removal by subsequent electrochemical treatment at high potential. We demon- strate that this combined activation process is essential to enhance platinum particle performance in catalyzing direct methanol fuel cell reactions, including methanol oxidation and oxygen reduction reac- tions. The studies in this work show promise in electrocatalysis applications of solution-based materials synthesis.展开更多
基金provided by K.N.Toosi University of Technology Research Council to conduct this research
文摘The electrocatalytic oxidation of methanol was studied over Ni, Co and Cu binary or ternary alloys on graphite electrodes in a NaOH solution （0.1 mol/L）. The catalysts were prepared by cycling the graphite electrode in solutions containing Ni, Cu and Co ions at cathodic potentials. The synergistic effects and catalytic activity of the modified electrodes were investigated by cyclic voltammetry （CV）, chronoamperometry CCA） and electrochemical impedance spectroscopy （EIS）. It was found that, in the presence of methanol, the modified Ni-based ternary alloy electrode （G/NiCuCo） exhibited a significantly higher response for methanol oxidation compared to the other samples. The anodic peak currents showed a linear dependency on the square root of the scan rate, which is a characteristic of a diffusion controlled process. During CA studies, the reaction exhibited Cottrellin behavior and the diffusion coefficient of methanol was determined to be 6.25× 10-6 cm2/s and the catalytic rate constant, K, for methanol oxidation was found to be 40×107 cm3/Cmol.s）. EIS was used to investigate the catalytic oxidation of methanol on the surface of the modified electrode.
基金the financial support of the Taiwan National Science Council
文摘Improving catalyst performance by studying the preparation parameters, material structures and analysis methods is important work for catalyst researchers. In this study, Cu-Pt nanocomposites with different metal ratios were synthesized on MWCNTs using a polyol method. The structures and morphologies of the nano hybrid catalysts were analyzed by XRD and TEM. The XRD results indicate that Pt and Cu formed a bimetallic solid solution. The average diameters of the Pt and Cu-Pt nanoparticles on MWCNTs were between 3-10 nm and 5-15 nm, respectively. The electrocatalytic behavior of methanol oxidation reactions was investigated by cyclic voltammery （CV）. Cu（20%）/[Pt/MWCNTs（1：4）], which contained an optimal degree of solid solution, enhanced the methanol oxidation to the greatest degree.
文摘Surfactant removal from the surface of platinum-based nanoparticles prepared using solution-based methods is a prerequisite to realize their high catalytic performance for electrochemical reactions. Herein, we report an effective approach combining acetic acid refluxing with an electrochemical process for the removal of amine- or thiol-based capping agents from the surface of supported-platinum nanoparticles. This strategy involves surfactant protonation by refluxing the supported-platinum particles in acetic acid followed by surfactant removal by subsequent electrochemical treatment at high potential. We demon- strate that this combined activation process is essential to enhance platinum particle performance in catalyzing direct methanol fuel cell reactions, including methanol oxidation and oxygen reduction reac- tions. The studies in this work show promise in electrocatalysis applications of solution-based materials synthesis.
