LAUSR

Selenium vacancy engineering has been realized in Co0.85Se nanoparticles via an anoxic melting strategy, where the vacancy content can be continuously controlled to modulate atomic disordering. The resulting Co0.85Se-30 catalyst requires a super low overpotential of 243 mV to achieve 10 mA cm-2 for the OER with a Tafel slope of 45.5 mV dec-1 and 70 h stability. In-depth electrochemical analysis finds that the outstanding properties are chiefly attributed to the dynamic Co-centers, giving the highest intrinsic activity (jCo = 6.49 A g-1 at η = 270 mV) and lowest apparent activation energy (42.43 kJ mol-1).