Benchmarking Steady-State Density Functional Theory for Modeling Electrocatalytic Reactions

Properly capturing the intricate effects induced by electrochemical potentials is essential for reliably modeling electrocatalytic reactions and guiding the rational design of electrocatalysts. In particular, potential-driven nonequilibrium effects, often inaccessible to conventional equilibrium-based approaches, play a pivotal role in elucidating the underlying reaction mechanisms. In this work, we benchmark a recently developed nonequilibrium ab initio approach based on steady-state density functional theory (SS-DFT) by performing calculations on four prototypical electrocatalytic reactions: the oxygen evolution reaction (OER), nitrogen reduction reaction (NRR), oxygen reduction reaction (ORR) and carbon dioxide reduction reaction (CO 2 RR). We systematically compare SS-DFT with conventional DFT-based methods, including constant charge (DFT-CC) and constant potential (DFT-CP) approaches. When the system 1 remains near equilibrium with only minor nonequilibrium effects, SS-DFT accurately reproduces conventional DFT results. However, under potentials that induce profound nonequilibrium effects, SS-DFT predicts significant changes in free energies compared to DFT-based methods, which facilitate adsorptions and reaction pathways. These findings demonstrate that SS-DFT provides a powerful framework for modeling electrocatalytic reactions and highlight the importance of incorporating nonequilibrium effects for the fundamental understanding of electrocatalytic mechanisms.