Fe-Doping-Accelerated Deep Reconstruction of KCoF₃ for Enhanced Alkaline Oxygen Evolution Reaction

Designing catalysts that can undergo deep reconstruction to form active oxyhydroxides for efficient oxygen evolution reactions (OER) remains urgently needed yet challenging. Herein, a series of KCo_{1- x}Fe_xF₃ was rationally synthesized, in which the leaching of K⁺ and F^- ions induces self-reconstruction during alkaline OER. Moreover, the introduction of Fe enhances the ionicity of the M-F bonds, promoting bond dissociation and inducing local structural disordering, strengthening the electrochemical reconstruction. In situ Raman reveals that the Co sites serve as the catalytic centers within the amorphous (Co, Fe)OOH active layer, and Fe incorporation increases the formation of active species and promotes deep reconstruction. Further studies reveal that Fe doping enables the OER mechanism to switch from a dual pathway of the adsorbate evolution mechanism and lattice oxygen-mediated mechanism (LOM) to a LOM, thus improving the OER performance. The reconstructed KCo_0.7Fe_0.3F₃ delivers a low overpotential of 257 mV at a current density of 10 mA cm^-2 and remains stable for over 100 h at 100 mA cm^-2, superior to that of commercial RuO₂. This work provides a rational method for deep reconstruction of the catalyst and fundamental insights into enhancing OER catalytic performance.