Synergistic Promotion of Large‐Current Water Splitting through Interfacial Engineering of Hierarchically Structured CoP−FeP Nanosheets with Rich P Vacancies

Abstract

AbstractThe development of hydrogen evolution reaction (HER) catalysts with high performance under large current density is still a challenge. Introducing P vacancies in heterostructure is an appealing strategy to enhance HER kinetics. This study investigates a CoP−FeP heterostructure catalyst with abundant P vacancies (Vp−CoP−FeP/NF) on nickel foam (NF), which was prepared using dipping and phosphating treatment. The optimized Vp−CoP−FeP catalyst exerted prominent HER catalytic capability, requiring an ultra‐low overpotential (58 mV @ 10 mA cm−2) and displaying robust durability (50 h @ 200 mA cm−2) in 1.0 M KOH solution. Furthermore, the catalyst demonstrated superior overall water splitting activity as cathode, demanding only cell voltage of 1.76 V at 200 mA cm−2, outperforming Pt/C/NF(−) || RuO2/NF(+). The catalyst‘s outstanding performance can be attributed to the hierarchical structure of porous nanosheets, abundant P vacancies, and synergistic effect between CoP and FeP components, which promote water dissociation and H* adsorption and desorption, thereby synergically accelerating HER kinetics and enhancing HER activity. This study demonstrates the potential of HER catalysts with phosphorus‐rich vacancies that can work under industrial‐scale current density, highlighting the importance of developing durable and efficient catalysts for hydrogen production.