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_z² orbitals of Mn sites leads to electrons occupying the σ orbital in Mn─*O₂, thereby favoring O₂ adsorption to initiate the ORR mechanism. In situ characterizations confirm that Mn 3d_z² 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.