Revealing dynamic structural evolution of V and P co-doping-induced Co defects as large-current water oxidation catalyst

•V/P codoped CoS2 was successfully constructed by feasible directional methods.•The catalyst exhibits flower-like structure with rich surface Co defects.•The anode in overall water splitting requires 1.87 V voltage to reach 500 mA cm−2.•The Co defects and surface-reconstructed V-CoOOH/CoS2 synergistically promote OER performance. Metallic defects can improve catalysts' intrinsic activity by regulating its electronic structure and enhancing conductivity. However, the impact of these defects on the kinetics of the oxygen evolution reaction (OER) has not been extensively studied. Here, a V/P codoped nanoflower-like CoS2 catalyst with rich Co defects on carbon cloth (V,P-CoS2/CC) is fabricated by feasible directional construction. The V,P-CoS2/CC validates extraordinary OER performance with overpotentials of 227/300 mV at 10/100 mA cm−2 and robust long-term stability. The enhanced single-electron spin resonance signal and higher lifetime strength indicate an increased number of surface Co defects induced by V/P codoping. Density functional theory (DFT) calculations verify that Co defects induced by V/P codoping of the surface reconstituted V-CoOOH/CoS2 catalyst can optimize the adsorption/desorption energy of oxygen-containing intermediates to accelerate OER process. Besides, the nanoflower-like morphology with large electrochemical active surface area and good hydrophilicity facilitates electrolyte diffusion/gas emission, thereby synergistically elevating OER performance.