Cobalt (oxy)hydroxide nanosheet arrays with exceptional porosity and rich defects as a highly efficient oxygen evolution electrocatalyst under neutral conditions

An oxidation-mediated defect and porosity enrichment strategy is developed for the synthesis of a new electrocatalyst consisting of cobalt (oxy) hydroxide nanosheet arrays (denoted as CoOxHy NSAs) grown on carbon cloth (CC), which feature a 3D hierarchical nanostructure with exceptional porosity and rich defects. The CoOxHy/CC shows exceptional activity and stability for the oxygen evolution reaction under neutral conditions, as indicated by its high current density of 38 mA cm (2) at 1.8 V, small Tafel slope of 121 mV dec (1), low overpotential of 430 mV, and 24 h durability at 10 mA cm (2) in 0.1 M phosphate buffer solution (PBS).