Understanding the Stability of Highly Active Catalysts for the Oxygen Evolution Reaction Using First-Principles Simulations

The activity-stability conundrum remains one of the biggest bottlenecks in the design of catalysts and electrocatalysts including the ones for the oxygen evolution reaction (OER), in electrochemical water-splitting for the production of hydrogen. Highly active catalysts for the OER, including rutile oxides such as RuO₂, IrO₂, and perovskite oxides such as SrRuO₃ and SrIrO₃, all have limited stability posing severe restrictions on their life-times and long-term use. Recently, several experimental studies have investigated potential dissolution mechanisms of these state-of-the art catalysts, but a detailed first-principles study comparing the different catalysts is still lacking.

Here, we use first-principles simulations with ab-initio thermodynamics and enhanced sampling methods to understand the dissolution of both rutile and perovskite oxides under OER operating conditions. Specifically, we consider the highly active but unstable RuO₂, IrO₂, SrRuO₃, SrIrO₃, as well as the highly stable but in the dark inactive TiO₂ and SrTiO₃ surfaces and constructed detailed Pourbaix diagrams involving several dissolution intermediates, to obtain the most stable surface stoichiometry under OER conditions. Additionally, ab-initio molecular dynamics simulations in the presence of explicit solvent, with enhanced sampling methods is used to obtain a mechanistic understanding of the surface evolution, providing a comprehensive atomistic understanding of dissolution under OER operating conditions.^1,2

Keywords: electrochemistry, OER, dissolution, DFT, MD, solvent effects, solid-liquid interfaces

Reference:

1. Abhinav S. Raman, Roshan Patel and Aleksandra Vojvodic, Surface stability of perovskite oxides under OER operating conditions: A first-principles approach, Accepted, Faraday Discussions, (2020).
2. L.C. Seitz, C. Dickens, K. Nishio, Y. Hikita, J. Montoya, A. Doyle, C. Kirk, A. Vojvodic, H. Y. Hwang, J. K. Nørskov, and T. F. Jaramillo, Science 353, 1011-1014 (2016)