Design Principle of Carbon-Supported Single-Atom Catalysts – Interplay between d-Orbital Periodicity and Local Hybridization

Carbon-based single-atom catalysts (SACs) have been widely investigated as a potential alternative for noble-metal-based catalysts for the hydrogen evolution reaction (HER) and the oxygen reduction reaction (ORR). The rational design of such catalysts requires not only physical intuitions but also practical descriptors that can be directly applied in experiments. In this work, we establish a practical theoretical framework based on a comprehensive data set of SACs compromising 28 metals, 5 types of local environments, and adsorption calculations for 4 adsorbates (e.g., H/O/OH/OOH). We disentangle the complex trend of H/OH adsorption as an interplay between d-orbital periodicity and local hybridization, allowing for the estimation of the catalytic performance solely on the basis of the number of valence electrons. By utilizing this data set and theoretical framework, we have also identified several promising catalyst candidates and overlooked design strategies.