Pt nanoparticles supported on sandwiched Ru/carbon nanocomposite as a bimetallic catalyst for methanol electrooxidation

Abstract

We report the preparation and characterization of a novel nanostructured bimetallic electrocatalyst (Pt/RuC) with Pt nanoparticles supported on the Ru/carbon (RuC) nanocomposite. The RuC with Ru nanocrystals sandwiched in the pore walls of mesoporous carbons was synthesized via template strategy using ordered mesoporous silica SBA-15 impregnated with a Ru precursor as a hard template and chemical vapor deposition method. A pure ordered mesoporous carbon (OMC) as a comparative support was prepared at identical experimental conditions. Nitrogen adsorption, X-ray diffraction, field-emission transmission electron microscope, and thermogravimetric analysis techniques were used to characterize the materials. The bimetallic Pt/RuC catalyst together with a monometallic catalyst Pt/OMC and a bimetallic catalyst PtRu/OMC were prepared by a conventional impregnation route, and their electrochemical properties were evaluated. It was found that the introduction of Ru nanoparticles into pore walls of porous carbon materials had negligible change in pore structure compared with OMC. Pt nanoparticles were highly dispersed in the pore channels of RuC with isolated Pt and Ru metal phases. The results showed that the Pt/RuC catalyst displayed the improved catalytic activity, CO tolerance, and good stability for room-temperature methanol electrooxidation possibly because of the unique sandwiched nanostructure of RuC composite support. Our investigation may provide a new insight into the understanding of methanol electrooxidation mechanism on bimetallic catalysts. © 2008 American Chemical Society.