Coordination Engineering of Single‐Atom Iron Catalysts for Oxygen Evolution Reaction

Abstract Developing highly active oxygen evolution reaction (OER) catalyst is essential to improve the performance of a water electrolyzer, where single‐atom catalysts (SACs) have shown promising performance in recent years. However, while SACs with various coordination environment have become experimentally feasible, knowledge about the structure‐performance relationship of SACs is still very limited, especially for the emerging multiple p ‐block element‐doped SACs substrates. Herein, by adjusting the coordination environment of single‐atom iron catalysts, 122 SACs with various substrates were designed for comprehensive analysis. Through spin‐polarized density functional theory calculations with van der Waals corrections, 52 stable single‐atom iron catalysts were identified. To analyze their OER performance, an OER volcano activity model was derived to predict their performance as the function of O* and HO* binding free energies. Interestingly, a Fe 1 B 1 C 1 N 2 ‐pen structure was found to have an outstanding OER activity (with a theoretical overpotential of 0.40 V vs . reversible hydrogen electrode) due to its unique adsorption mode that strengthens HO‐bonding by forming the Fe−OH−B bond. Based on these results, the OER performance of 26 TM 1 /B 1 C 1 N 2 ‐pen (TM=Ti−Zn, Zr−Cd, and Hf−Au) SACs were determined based on this unique coordination environment by B‐doping. Most importantly, this study shows that the OER performance of SACs can be significantly improved by tuning the coordination environment of an active metal center.