Modulating surface sulfur residues on CoFe (oxy)hydroxides via H2O2 oxidation for enhanced oxygen evolution.

and operates stably for 120 h. Mechanistic studies reveal that an appropriate residual sulfur level enhances the OER kinetics by downshifting the d-band center to optimize intermediate adsorption, while simultaneously lowering the work function and increasing carrier density to accelerate interfacial charge transfer. Excessive sulfur removal degrades performance. This work offers a new perspective for designing OER electrocatalysts through rational regulation of surface residual species.