title: Unifying the 2e(-) and 4e(-) Reduction of Oxygen on Metal Surfaces.
abstract: Understanding trends in selectivity is of paramount importance for multi-electron electrochemical reactions. The goal of this work is to address the issue of 2e(-) versus 4e(-) reduction of oxygen on metal surfaces. Using a detailed thermodynamic analysis based on density functional theory calculations, we show that to a first approximation an activity descriptor, ΔGOH*, the free energy of adsorbed OH*, can be used to describe trends for the 2e(-) and 4e(-) reduction of oxygen. While the weak binding of OOH* on Au(111) makes it an unsuitable catalyst for the 4e(-) reduction, this weak binding is optimal for the 2e(-) reduction to H2O2. We find quite a remarkable agreement between the predictions of the model and experimental results spanning nearly 30 years.
authors: Venkatasubramanian
authors: V
authors: Viswanathan
authors: Heine Anton
authors: HA
authors: Hansen
authors: §Center for Atomic-scale Materials Design, Department of Physics, Technical University of Denmark, DK-2800, Lyngby, Denmark.
authors: Jan
authors: J
authors: Rossmeisl
authors: ∥SUNCAT, SLAC National Accelerator Laboratory, Menlo Park, California 94025-7015, United States.
authors: Jens K
authors: JK
authors: Nørskov
keywords: activity volcano; electrocatalysis; fuel cells; hydrogen peroxide; lithium-air batteries; selectivity