Controlled synthesis of Se-supported Au/Pd nanoparticles with photo-assisted electrocatalytic activity and their application in self-powered sensing systems

Bimetallic nanoparticles (NPs) have received increasing attention for their outstanding catalytic activity which the corresponding monometallic NPs can hardly achieve. In this paper, we developed a facile approach to prepare Se-supported Au/Pd NPs with high and photo-assisted electrocatalytic activity. Cyclic voltammetry (CV) measurements showed that the electrocatalytic activity of the Se-supported Au/Pd NPs was dependent on the Pd content. This result indicates that the interface between Pd and Au plays a vital factor in the electrocatalytic activity, while the individual metal components in the Se/Au/Pd system are of minor relevance for such activity. The Se-supported Au/Pd NPs exhibited mass activities of 4.25 (A/mg_Pd) and 1.21 (A/mg_Au+Pd) toward ethanol oxidation, which were higher than that of the commercial Pd/C catalyst (0.36 A/mg_Pd). The electrocatalytic activity of Se-supported Au/Pd NPs was further enhanced by 2.4 times under solar light irradiation due to the photoelectrochemical effect of the Se NPs. It was further demonstrated in this paper that the presence of Se-supported Au/Pd NPs is crucial in self-powered electrochemical sensing systems as the overall sensitivity is significantly improved.