Interface Engineering of Ni3Fe and FeV2O4 Coupling with Carbon-Coated Mesoporous Nanosheets for Boosting Overall Water Splitting at 1500 mA cm–2

Constructing a heterojunction is vital to increase the performance of non-noble metal catalysts for overall water splitting (OWS) at large current density. Herein, we synthesize a Ni 3 Fe/FeV 2 O 4 heterojunction catalyst with a carbon-encapsulated mesoporous nanosheet structure self-supported on nickel foam (NF) by hydrothermal and annealing processes. The obtained catalyst inherits the merits of Ni 3 Fe and FeV 2 O 4, and the heterostructure can efficiently enhance the catalytic activity. Besides, the carbon layer combined with mesoporous nanosheets could provide more active sites to improve the performance. Low overpotentials (220/350 and 44/366 mV at ±10/±1500 mA cm –2 ) are required for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). For OWS, a potential of 1.51 V is required to reach 10 mA cm –2 and is maintained at 1500 mA cm –2 for 100 h in 6.0 M KOH at 60 °C. This work thus introduces a valuable and durable catalyst for OWS at large current density.