Electrocatalysis of Oxygen Reduction by Au Nanoparticles Electrodeposited on Polyoxometalate-Modified Electrode Surfaces

Abstract

The effect of polyoxometalate monolayers on the electrodeposition of Au nanoparticles (AuNPs) on glassy carbon (GC) surfaces was examined by electrochemical and scanning electron microscope techniques. The presence of <TEX>$SiMo_{12}O^{4-}_{40}$</TEX>-layers resulted in average particle sizes of ca. 60 nm, which is larger than AuNPs deposited on bare GC surfaces. AuNPs electrodeposited on <TEX>$SiMo_{12}O^{4-}_{40}$</TEX>-modified GC surfaces for 20 s exhibited the best electrocatalytic activity for oxygen reduction. This system exhibited similar or slightly better efficiency for oxygen reduction than a bare Au electrode. Rotating disk electrode experiments were also performed and revealed that the catalytic reduction of oxygen on AuNPs deposited on <TEX>$SiMo_{12}O^{4-}_{40}$</TEX>-modified GC electrodes is a two-electron process.