Cation vacancy-induced lattice oxygen oxidation mechanism for ultra-stable OER electrocatalysis

Catalysts adhere to the adsorbate evolution mechanism (AEM) are constrained by the linear scaling relationship between the adsorbates *OOH and *OH, leading to a theoretical overpotential of approximately 370 mV. The lattice oxygen activation mechanism (LOM) is a promising strategy for developing highly active oxygen evolution reaction (OER) electrocatalysts, but it struggles to maintain the structural stability of the catalyst. Herein, transition metal oxide catalysts (M_xO_y-M) enriched with metal cation vacancies (V_M) have been successfully built, demonstrating the OER mechanism of metal oxides changing from AEM to LOM with outstanding structural and electrocatalytic stability. Notably, the Co₃O₄-M catalyst maintains stable operation as long as 240 h at high current densities of 1 A cm^-2 in harsh industrial condition (30 % KOH and 85 ℃). Density functional theory (DFT) calculations reveal that the downward displacement of the d-band center of the metal in M_xO_y-M catalysts and the upward displacement of the O 2p band center result in increased orbital overlap, thereby augmenting the covalency of the M-O bond, which effectively facilitates the LOM reaction pathway while concurrently improving the OER stability. This study has provided a universal method for regulating the transformation of the OER mechanism and facilitated the development of new efficient lattice oxygen redox OER electrocatalysts.