Photo-excited in situ loading of Pt clusters onto rGO immobilized SnO2 with excellent catalytic performance toward methanol oxidation

Abstract

Maximizing the surface area and the exposed active sites of Pt-based catalysts is one of the most effective strategies to improve their electrocatalytic performance. We here present an environmentally friendly construction of a two-dimensional Pt/SnO2/reduced-graphene-oxide (rGO) nanocomposite as a active and durable electrocatalyst. Initially, liquid-phase laser ablation generated highly reactive SnOx nanoparticles (NPs) were used as a precursor to transform the graphene oxide into rGO. Simultaneously, the initial amorphous-like SnOx can further crystallize into SnO2 NPs, which were uniformly anchored onto rGO sheets. Subsequently, the electrons photo-excited from semiconductor SnO2 were used as green reducing agents, which can in situ reduce the PtCl62+ ions to form ultrafine Pt NPs with an average size of about 1–2nm that uniformly dispersed onto SnO2 NPs. Compared with Pt/rGO catalysts without SnO2 modification, the Pt/SnO2/rGO hybrid ternary catalysts not only show larger electrochemical active surface area and higher catalytic activity toward methanol oxidation, but also exhibit better long-term cycle stability and better tolerance toward CO-like species. Such significantly enhanced electrochemical performance could be attributed to the uniformly dispersed fine Pt NPs and the synergetic effect from the hybrid noble metal-semiconductor-carbon network components.