Au/Ta(110) and Au/Nb(110) as Highly Active, Stable, and Inexpensive Catalysts for Oxygen Reduction Reaction on Hydrogen Fuel Cell Cathodes: Prediction from First Principles

Abstract

AbstractWe propose here structures – a gold monolayer on early transition metal surfaces – as a promising alternative to the prohibitively expensive platinum‐based electro‐catalysts for the oxygen reduction reaction (ORR), which occurs on hydrogen fuel cell cathodes. Based on existing knowledge and educated guesses, we preselect Au/Nb, Au/Ta, Au/Mo, and Au/W as potential catalysts. Our calculations show that these materials are stable and have very high dissolution potentials. A deviation from the linear scaling for the binding energy of ORR intermediates, revealed for Au/Nb and Au/Ta, has a desired impact on the ORR thermodynamics. We find it to be a result of hybridization of p‐electronic states of oxygen belonging the OOH‐radical and Au‐pz states. The calculated ORR free energy diagrams show that the ORR onset potentials for Au/Nb and Au/Ta are significantly higher than that for Pt. We thus predict two inexpensive, thermodynamically and electrochemically stable, and highly active ORR catalysts.