DFT Prediction of Oxygen Reduction Reaction on Palladium−Copper Alloy Surfaces

Abstract

The high cost of proton exchange membrane fuel cells (PEMFCs) comes largely from the use of platinum-containing electrocatalysts. Despite significant progress made the past decade on reducing the platinum catalyst loading in the PEMFC electrodes, further substantial cost reductions require the replacement of platinum with less expensive nonplatinum electrocatalytic materials. In this study, PdCu alloys have computationally been investigated as possible non-Pt catalysts for oxygen reduction reaction (ORR) in PEMFCs. We used density functional theory (DFT) calculations to determine the structural preference and ORR activity as a function of the composition and structure. Five PdCu alloy surface structures, B2, L1_2, L1_0, L1_1-nonlayered, and L1_1-layered, were considered, and the layered L1_1 surface structure was found to exhibit significantly improved ORR kinetics compared to that of pure Pd.