Approaching the Sabatier optimum <i>via</i> a triple-defect synergistic strategy for enhanced oxygen evolution reaction

The development of highly efficient and stable oxygen evolution reaction (OER) electrocatalysts represents a critical challenge for advancing water splitting hydrogen production technology. In this work, we report a novel defect engineering strategy through synergistic Fe/Al doping and Co vacancy construction in a CoMOF precursor, achieving remarkable performance enhancement after electrochemical reconstruction. Density functional theory (DFT) calculations elucidate the cooperative mechanism of Fe/Al dopants and Co vacancies, which positions the Gibbs free energy of O (Δ<i>G</i>_O*) exactly at the center of Δ<i>G</i>_OH* and Δ<i>G</i>_OOH*, thereby dramatically decreasing the catalytic overpotential and boosting the catalytic activity. Experimental characterization studies conclusively demonstrate the successful electronic structure modulation achieved through this triple-defect (Fe/Al doping and Co vacancy) synergistic strategy, which exhibits exceptional electrocatalytic performance with an ultralow overpotential of 229 mV at 10 mA cm^-2. The concerted effects of these engineered defects not only remarkably enhance the intrinsic activity through optimized electronic configurations but also significantly improve charge transfer kinetics. This innovative defect-engineering paradigm establishes a universal methodology for the rational design of high-performance electrocatalysts across diverse electrochemical energy conversion systems.