Ruthenium-free, carbon-supported cobalt and tungsten containing binary & ternary Pt catalysts for the anodes of direct methanol fuel cells

Abstract

Carbon supported Pt, PtCo, PtW and PtCoW catalysts were prepared by wet impregnation and their catalytic activities for electrooxidation of methanol in the acidic environment of direct methanol fuel cells (DMFCs) were determined at room temperature. The catalysts were characterized by X-ray powder diffraction and X-ray photoelectron spectroscopy and their electrochemical properties were measured by cyclic voltammetry and CO anodic stripping voltammetry. The ternary PtCoW/C catalyst was found to be the best in terms of activity and CO tolerance although the binary PtCo/C and PtW/C catalysts also outperformed Pt/C. The performance of PtCoW/C could be rationalized in terms of synergistic interactions where Co promoted the initiation of methanol dehydrogenation, W contributed to CO removal through the generation of oxygenated species and expedient removal of protons. The inclusion of base metals (Co and W) other than ruthenium provides additional options in the design of catalysts for DMFCs.