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.

中文翻译：

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纳米/微米级集成蘑菇形亲水CoP @ Ni-CoP，具有优化的气泡释放性能，可实现高效的水分解催化

基于电催化的总水分解是一种易于构建且具有成本效益的技术，可以大规模实现清洁和可再生的氢能。在本文中，我们证明了在碱性条件下，多尺度集成蘑菇形磷化钴@镍-磷化钴（表示为CPNCP）作为氢析出反应（HER）和氧析出反应（OER）的催化剂的研究。具有独特的纳米/微米级3D“主体”和“头部”结构的催化剂可以直接在镍基底上生长，从而促进高电导率，高亲水性和有效的气泡释放，为实际的水分解装置提供了潜在的候选者。此外，还揭示了CPNCP作为双功能催化剂对于整个水分解反应的实际意义，其值为10 mA·cm^–2可在1.49 V的低过电势下实现电流密度，并在10和200 mA·cm ^{–2的条件下}保持40 h且几乎没有劣化。同样，连续反向水分解超过6小时也能实现，这表明CPNCP在持续不断的电源中断方面具有很高的耐力。计算得出，HER和OER的周转频率分别为3.208和1.072 s ^–1，描述了CPNCP的出色性能。这项工作可能会激发优化过渡金属基纳米材料的结构，促进其在其他可再生能源选择中的应用。