Preparation, Characterization and Electrocatalytic Properties of Promoted PtMoSi/C Catalysts

PtMoSi/C nanocatalysts were prepared by chemical reduction using formaldehyde, H2, and hydrazine as reducing agents, respectively. The nanocomposites were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). XRD patterns showed a face-centered cubic crystal structure, and TEM images indicated that the nanoparticles that were uniformly dispersed on carbon were 3-4 nm in diameter. XPS analysis revealed that the catalysts contained mostly Pt(0), Mo(VI), and Si(IV). The effects of preparation methods and additives on the catalytic activity were then studied by linear sweep voltammetry (LSV) and cyclic voltammetry (CV). It was found that the PtMoSi/C nanocatalysts (nPt:nMo=3:1 was the optimal ratio of Pt to Mo) prepared using formaldehyde as reducing agent showed higher electrocatalytic activity and better tolerance to poisoning species in methanol oxidation than the homemade PtRu/C and the commercial E-TEK PtRu/C catalysts, and this could be ascribed to the high dispersion of Pt nanoparticles on the carbon by the addition of silicomolybdic acid.