Synthesis of highly active nanostructured PtRu electrocatalyst with three-dimensional mesoporous silica template

Abstract

Nanostructured PtRu material has been successively synthesized via chemical co-reduction of hexachloroplatinic acid and ruthenium trichloride using three-dimensional (3D) hexagonal mesoporous SBA-12 silica as a solid template, and has been studied as an electrocatalyst toward methanol electro-oxidation. The ordered nanostructure of the PtRu particles has been disclosed by transmission electron micrographs and is characterized by regular pores of ca. 3.0 ± 0.3 nm in diameter separated by walls of ca. 3.0 ± 0.3 nm thick. X-ray diffraction and energy dispersive X-ray spectroscope studies indicate that the PtRu material comprises of complicated phases rather than a single alloy phase of Pt and Ru. The specific electrochemical surface area of the nanostructured powder measured using both CO and underpotential deposited Cu stripping techniques is 74–78 m 2 g –1, higher than that of unsupported precious metal catalysts prepared using standard techniques. The combination of high surface area and periodic nanostructure of the templated PtRu makes it an interesting promising fuel cell electrocatalyst. This has been demonstrated by the high activity of the templated PtRu towards the methanol electrooxidation. Therefore the solid template route based on 3D mesoporous silica with controlled pore size and high pore interconnectivity provides an interesting alternative to produce promising high-surface-area electrode materials.