Large current density for oxygen evolution from pyramidally-coordinated Co oxide

Developing efficient electrocatalyst at large current densities to meet the requirement of industrial water splitting is a big challenge today. Herein, we report a class of catalyst, BiCoO₃ with pyramidally coordinated Co³⁺. BiCoO₃ exhibits a large current density of 1000 mA cm⁻² at a low overpotential of 402 mV and the overpotential even reduces to only 303 mV to achieve 1000 mA cm⁻² by replacing Co with Fe, which belongs to the first-class level among large-current-densities electrocatalysts reported so far. Different from artificially created oxygen vacancies to optimize the bonding strength of the intermediate for enhancement of OER activity, BiCoO₃ has the rich active sites and the shortest reaction pathway leading to a large current density, as structurally every Co-O cluster has one oxygen vacancy. This work opens a new avenue for enhanced OER activity at high current densities via optimizing the arrangement of ligand vacancies.