Nano/Microscale Integrated Mushroom-Shaped Hydrophilic Cop@Ni-Cop With Optimized Gas Bubble Release For High-Performance Water Splitting Catalysis

Overall water splitting based on electrocatalysis is an easily constructed and cost-effective technology for achieving clean and renewable hydrogen energy on a large scale. Herein, we demonstrate the investigation of multiscale integrated mushroom-shaped cobalt phosphide@nickel-cobalt phosphide (denoted CPNCP) as a catalyst for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline conditions. The catalyst with a unique nano/microscale 3D "body" and "head" structure can be grown directly on a nickel substrate, promoting high conductivity, high hydrophilicity, and effective gas bubble release, bringing in a prospective candidate for practical water splitting devices. Furthermore, the practical relevance of CPNCP as a bifunctional catalyst for the overall water splitting reaction is revealed, with 10 mA.cm(-2) to achieve current density at a low overpotential of 1.49 V and maintained at 10 and 200 mA.cm(-2) for 40 h with little degradation. Also, the continuous reverse water splitting for over 6 h is capable, demonstrating CPNCP's high endurance toward constant power interruption. The turnover frequencies are calculated to be 3.208 and 1.072 s(-1) for HER and OER, respectively, describing an excellent performance of CPNCP. This work may inspire optimizing structures of transition-metal-based nanomaterials, promoting their applications in other renewable energy options.