PNNL

Abstract

Redox reactions at metal oxide (MOx) surfaces are implicated in many catalytic and energy conversion processes. However, the fundamental thermodynamics dictating such interfacial reactivity remain ill-defined, in part because of the frequent involvement of proton as well as electron transfers. Herein, we describe an approach connecting the pH-dependent electrochemical response of MOx thin films with the bond dissociation free energies (BDFEs) of their electroactive surface O-H bonds. Using NiO as a case study, we show that these BDFEs can predict much of the observed proton-coupled electron transfer (PCET) reactivity at the MOx surface. Analyzing the PCET reactivity of MOx materials in terms of BDFEs could enable new approaches for designing more active and efficient catalysts and electrocatalysts for important PCET reactions.