In situ self-reconstruction of NiMoO4 promoted by Fe doping to activate the lattice oxygen mechanism for water oxidation

Electrochemical self-reconstruction is a critical process in transition metal-based electrocatalysts, as it governs the generation of catalytically active species during the oxygen evolution reaction (OER). In the NiMoO 4 system, γ-NiOOH is recognized as the truly active species, however, its slow and shallow reconstruction severely limits catalytic performance. Herein, a Fe doping strategy is employed to accelerate the in situ self-reconstruction kinetics of NiMoO 4 . A series of Fe-doped NiMoO 4 catalysts were synthesized via a one-step hydrothermal method, and the influence of Fe doping on the structural evolution and catalytic mechanism of the materials was systematically investigated. Fe incorporation induces preferential exposure of low-index crystal planes and lattice distortion, which facilitates selective Mo leaching and modulates the electronic structure of Ni. This synergistic effect not only enhances the extent but also accelerates the rate of self-reconstruction, thereby promoting the formation of low-crystallinity γ-NiOOH and consequently activating the lattice oxygen mechanism (LOM). As a result, 30 %Fe-NiMoO 4 -R exhibits a low overpotential of 205 mV@10 mA cm −2 , with stability for 400 h at 50 and 100 mA cm −2 . This work clarifies the role of Fe doping in tuning reconstruction dynamics and provides valuable insights into the design of efficient OER catalysts via lattice oxygen activation.