Oxygen evolution reaction mechanism on platinum dioxide surfaces based on density functional theory calculations

Abstract

The oxygen evolution reaction (OER) counterbalances the hydrogen evolution reaction (HER) during water dissociation under an electric field. Platinum (Pt) group metals and their oxides exhibit considerable durability as electrocatalysts for water dissociation. However, an atomic-level understanding of the OER on Pt-oxide surfaces at high potential remains elusive because of the limited experimental techniques for tracking dynamic surface species involved in adsorption, electron transfer, or interactions. Herein, the OER mechanisms involving water nucleophilic attack (WNA) and intramolecular oxygen coupling (IMOC) were studied on Pt and platinum dioxide (PtO₂) surfaces using density functional theory (DFT) calculations, indicating that the WNA mechanism dominates the OER on Pt and PtO₂ electrode surfaces. The OER activity on the PtO₂(100) surface is better than the PtO₂(111) surface due to the high overpotential obtained on PtO₂(111). These findings offer valuable insights into the OER mechanism on oxidized Pt surfaces and suggest new strategies for designing and optimizing Pt-based catalysts for improved stability and performance.