Tuning α-MnOOH Formation via Atomic-Level Fe Introduction for Superior OER Performance

Abstract

The arrangement of atoms in the catalyst directly impacts the catalytic performance. Herein, a heteroatom doping strategy is found as an effective approach for the regulation of MnO2 crystal reconstruction during the oxygen evolution reaction (OER), thereby ensuring and optimizing the performance of the catalyst. Real-time tracking of dynamic surface reconstruction reveals that δ-MnO2 transforms into the less active γ-MnOOH phase, while single-atom Fe doping facilitates the formation of highly active α-MnOOH phase. The formation of asymmetric Fe─O─Mn bonds induce lattice distortions of MnO2 and promote electron transfer from Fe to Mn with an increase in the Mn3⁺ content, which is conducive to intensifying oxygen spillover and is a crucial factor for OER activity. Theoretical calculations also demonstrate that the effective active sites regulated in the representative catalyst of α-MnOOH can reduce the energy barrier for a crucial step during the OER process (the *O to *OOH transition), thus significantly enhancing catalytic performance. The typical catalyst achieves the successful regulation of crystal reconstruction processes through heteroatom doping, which holds significant implications for developing a new class of catalysts, not limited to the OER catalysts reported in this study.