Ambient Fast Synthesis of Superaerophobic/Superhydrophilic Electrode for Superior Electrocatalytic Water Oxidation

Developing cost-effective and facile methods to synthesize efficient and stable electrocatalysts for large-scale water splitting is highly desirable but remains a significant challenge. In this study, a facile ambient temperature synthesis of hierarchical nickel-iron (oxy)hydroxides nanosheets on iron foam (FF-FN) with both superhydrophilicity and superaerophobicity is reported. Specifically, the as-fabricated FF-FN electrode demonstrates extraordinary oxygen evolution reaction (OER) activity with an ultralow overpotential of 195 mV at 10 mA cm(-2) and a small Tafel slope of 34 mV dec(-1) in alkaline media. Further theoretical investigation indicates that the involved lattice oxygen in nickel-iron-based-oxyhydroxide during electrochemical self-reconstruction can significantly reduce the OER reaction overpotential via the dominated lattice oxygen mechanism. The rechargeable Zn-air battery assembled by directly using the as-prepared FF-FN as cathode displays remarkable cycling performance. It is believed that this work affords an economical approach to steer commercial Fe foam into robust electrocatalysts for sustainable energy conversion and storage systems.