DFT insights into nonmetal-induced local electronic confinement and ORR/OER activity modulation in Fe single-atom catalysts.

The development of high-durability and low-cost bifunctional single-atom catalysts is crucial for enhancing the oxygen reduction and oxygen evolution reaction (ORR/OER) performance of advanced energy storage devices and facilitating their commercialization. Based on density functional theory (DFT), a systematic investigation of B, P, S, and O doped Fe-based single-atom catalysts supported on graphene was performed to elucidate the microscopic mechanisms governing bifunctional catalytic activity, with emphasis on doping sites and non-metal dopant species. The results indicate three Fe-based single-atom catalysts of FeN7-P, FeN7-O, and FeN8-S with distinct doping configurations exhibit stable and relatively high bifunctional activity, with ΔE values (ηORR + ηOER) of 0.76 V, 0.83 V, and 0.77 V, respectively. The non-metal doping induced structural reorganization and bond modulation not only optimizes electronic transport pathways but also enhances the regulation of adsorption behaviors of reaction intermediates, thereby providing a theoretical foundation for the design of efficient non-precious metal ORR/OER catalysts.