LAUSR

Developing efficient and durable electrocatalysts for the oxygen evolution reaction (OER) in acidic media is attractive but still challenging. In this study, ultrafine defective RuO2 nanoparticles are successfully prepared on carbon cloth by means of dip‐coating, annealing, and acid etching. As a self‐supported electrocatalyst, it exhibits an ultralow overpotential of 179 mV in 0.5 m H2SO4. More importantly, the high activity can be well maintained for 20 h. The density functional calculations revealed that the defect can not only increase the number of active sites but also improve the intrinsic OER activity.