Spin‐State Manipulation of Atomic Manganese Center by Phosphide‐Support Interactions for Enhanced Oxygen Reduction

Abstract Oxygen reduction reaction (ORR) kinetics are closely related to the electronic structure of active sites. Herein, a single‐atomic Mn catalyst decorated with adjacent MoP nanocrystals (MoP@Mn SAC ‐NC) is reported. The decoration of MoP drives the electronic structure transition of Mn sites from low‐spin to high‐spin states through an electronic phosphide‐support interaction. The rearranged electron occupation in 3d xz‐yz and 3d z 2 orbitals of Mn sites leads to electrons occupying the σ orbital in Mn─*O 2 , thereby favoring O 2 adsorption to initiate the ORR mechanism. In situ characterizations confirm that Mn 3d z 2 orbital occupation state can activate molecular O₂ and optimize the adsorption of the *OOH intermediate. As a result, the MoP@Mn SAC ‐NC displays an outstanding alkaline ORR half‐wave potential ( E 1/2 = 0.894 V), excellent peak power densities (173/83 mW cm −2 for liquid/solid‐state Zn‐air batteries, respectively), and long‐term stability (840 h) superior to commercial Pt/C. This work provides profound insights into spintronics‐level engineering, guiding the design of next‐generation high‐performance ORR catalysts.