Rational introduction of S and P in multi-stage electrocatalyst to drive a large-current-density water oxidation reaction and overall water splitting

Rational design and construction of electrocatalysts that can work well at large current densities are imperative for water splitting. Herein, a multi-stage P–Ni3S2/NiFe/NF electrocatalyst was rationally designed by introducing heteroatoms (S and P) and heterostructure construction. Benefitting from the optimized electronic structure configuration by the synergistic incorporation of S and P, the as-prepared P–Ni3S2/NiFe/NF electrocatalyst exhibits remarkable activity and stability towards oxygen evolution reaction (OER) in alkaline media, yielding ultralow overpotentials of 250 mV and 372 mV at the current densities of 100 mA/cm2 and 1000 mA/cm2, respectively. Moreover, its multi-stage heterostructure also endows the electrocatalyst with unique multifunctional properties, making it can realize overall water splitting under a low cell voltage of 1.57 V at 10 mA/cm2, and has long-term stability. This work demonstrates the importance of rational introduction of heteroatoms and interface/surface engineering for advanced electrocatalytic materials.