Oxygen Vacancies Dominated NiS₂/CoS₂ Interface Porous Nanowires for Portable Zn–Air Batteries Driven Water Splitting Devices

Abstract

The development of highly active and stable oxygen evolution reaction (OER) electrocatalysts is crucial for improving the efficiency of water splitting and metal-air battery devices. Herein, an efficient strategy is demonstrated for making the oxygen vacancies dominated cobalt-nickel sulfide interface porous nanowires (NiS₂ /CoS₂ -O NWs) for boosting OER catalysis through in situ electrochemical reaction of NiS₂ /CoS₂ interface NWs. Because of the abundant oxygen vacancies and interface porous nanowires structure, they can catalyze the OER efficiently with a low overpotential of 235 mV at j = 10 mA cm^-2 and remarkable long-term stability in 1.0 m KOH. The home-made rechargeable portable Zn-air batteries by using NiS₂ /CoS₂ -O NWs as the air-cathode display a very high open-circuit voltage of 1.49 V, which can maintain for more than 30 h. Most importantly, a highly efficient self-driven water splitting device is designed with NiS₂ /CoS₂ -O NWs as both anode and cathode, powered by two-series-connected NiS₂ /CoS₂ -O NWs-based portable Zn-air batteries. The present work opens a new way for designing oxygen vacancies dominated interface nanowires as highly efficient multifunctional electrocatalysts for electrochemical reactions and renewable energy devices.