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 (MO-M) enriched with metal cation vacancies (V) have been successfully built, demonstrating the OER mechanism of metal oxides changing from AEM to LOM with outstanding structural and electrocatalytic stability. Notably, the CoO-M catalyst maintains stable operation as long as 240 h at high current densities of 1 A cm 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 MO-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.