Electrochimica Acta, Vol.83, 354-358, 2012
Electronic effect on oxidation of formic acid on supported Pd-Cu bimetallic surface
Vapor deposition method is used to prepare layered Pd-Cu bimetallic model catalytic surfaces, with different thickness of Pd, supported on glassy carbon. Charge transfer from Pd to Cu produces a positive binding energy (BE) shift for the overlayer Pd 3d and an opposite shift for Cu 2p as measured by X-ray photoelectron spectroscopy (XPS). Similarly, the d-band center moves away from the Fermi level as the thickness of Pd decreased for these bimetallic materials. This electronic perturbation of the Pd-Cu systems results in a drastic increase in current density and an improved stability for formic acid electro-oxidation. Our findings indicate that layered Pd-Cu bimetallic surfaces with Pd layers thicker than 1 nm do not form a surface alloy at room temperature and are better electrocatalytic materials than Bulk Pd and could be used to enhance direct formic acid fuel cell (DFAFC) performance. Published by Elsevier Ltd.
Keywords:Formic acid electrochemical-oxidation;XPS;Density of state;Layered bimetallic surface;Direct formic acid fuel cell