NiFeCr–S/NiS/NF with modified 2D nanosheet array as bifunctional electrocatalysts for overall water splitting

Hetero-structured NiFeCr–S/NiS nanosheet arrays supported on nickel foam (NiFeCr–S/NiS/NF) were prepared by sulfurizing the hetero-structured hybrid of NiFeCr-layered double hydroxides/NiS/NF (NiFeCr-LDH/NiS/NF) through sequential hydrothermal method and vapour deposition method. Benefiting from the abundant NiS/NiFeCr–S interfaces and the two-dimensional nanosheet structure, the as-prepared catalyst displays an overpotential at 10 mA cm−2 of 94 mV for oxygen evolution reaction and 131 mV for hydrogen evolution reaction, respectively, which is better than the non-sulfurized NiFeCr-LDH/NiS/NF and NiFeCr-LDHs/NF, as well as the sulfurized NiFeCr–S/NF and NiS/NF. In the self-assembled device using NiFeCr–S/NiS/NF as both cathode and anode, the overall water splitting reaction can be driven at 1.53 V of cell voltage to achieve the current density of 10 mA cm−2.