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.