Orbital hybridizations in single-atom catalysts for electrocatalysis

Single-atom catalysts (SACs) are rapidly standing at the forefront of catalytic development due to their unique structures with significantly different catalytic activity, selectivity, and stability from conventional nanocatalysts. The electronic properties and catalytic performances of SACs hinge on the results of orbital hybridization of isolated central atoms with ligand atoms as well as of central atoms with bonding atoms provided by intermediates. Therefore, we conduct multifaceted explorations around orbital hybridizations in single-atom catalysis to elucidate the structure-activity relationships. Firstly, we introduce the basic theoretical knowledge related to orbital hybridizations, and summarize the main descriptors of orbital hybridizations, focusing on the discussion of the types of orbital hybridizations in single-atom catalysis. Then, we briefly sum up the application of orbital hybridizations in single-atom electrocatalysis and put forward important strategies for regulating orbital hybridizations in SACs to improve the catalytic performances. Finally, we present a personal perspective on the future challenges and opportunities of orbital hybridizations in single-atom catalysis.