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

Luo, Zuyang; Xie, Jiayin; Cheng, Jinshan; Wei, Fengli; Lyu, Shuai; Zhu, Junjiang; Shi, Xiaofeng; Yang, Xiulin et al. · Adv Mater · 2025

basic_science · Level V

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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<sub>SAC</sub>-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<sub>xz-yz</sub> and 3d<sub>z</sub> <sup>2</sup> orbitals of Mn sites leads to electrons occupying the σ orbital in Mn─*O<sub>2</sub>, thereby favoring O<sub>2</sub> adsorption to initiate the ORR mechanism. In situ characterizations confirm that Mn 3d<sub>z</sub> <sup>2</sup> orbital occupation state can activate molecular O₂ and optimize the adsorption of the *OOH intermediate. As a result, the MoP@Mn<sub>SAC</sub>-NC displays an outstanding alkaline ORR half-wave potential (E<sub>1/2</sub> = 0.894 V), excellent peak power densities (173/83 mW cm<sup>-2</sup> 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.