Electrocatalytic performance of gold nanoparticles supported on activated carbon for methanol oxidation in alkaline solution

Gold nanoparticles supported on activated carbon (Au/C) are prepared by rapid reduction of AuCl₄^- on the surface of activated carbon with KBH₄ in the presence of polyvinylpyrrolidone. Through the characterization of the transmission electron microscope, the Au nanoparticles (AuNPs) are highly well dispersed on the carbon support. Cyclic voltammetry, quasi-steady-state polarization, and electrochemical impedance spectroscopy methods are employed to investigate the catalytic activity of the Au/C catalyst for the methanol electro-oxidation (MEO) and the reaction kinetics. The results indicate that the Au/C catalyst shows good catalytic activity toward the MEO, and the weakly adsorbed OH^- on the surface of AuNPs has auxiliary catalysis for the MEO. On the basis of this crucially auxiliary catalysis, a novel mechanism of the rate-determining step of the MEO catalyzed by Au/C in alkaline solution is proposed.