Ni3S2-embedded NiFe LDH porous nanosheets with abundant heterointerfaces for high-current water electrolysis

Ni3S2-embedded NiFe LDH heterostructured porous nanosheets were in situ grown on nickel foam (Ni3S2-NiFe LDHs /NF) via a one-pot solution method mediated by NaHS at room temperature in 15 min. Benefiting from the abundant Ni3S2-NiFe LDH interfaces, the as-prepared catalyst delivers 50, 500 and 1000 mA cm−2 with an overpotential of only 230, 285 and 303 mV for oxygen evolution reaction, respectively, registering as one of the best performing non-precious metal OER catalysts. In situ and ex situ analysis reveal that the Ni3S2 was in situ partially transformed under an electrooxidation environment into NiOOH over an equally important electrically conductive Ni3S2 to drive proficient catalysis. This strategy can be extended to fabricate Ru-Ni3S2-NiFe LDHs/NF electrocatalyst for high active hydrogen evolution reaction. Coupling these two catalysts achieved remarkable current densities of 10, 100 and 500 mA cm−2 at low voltages of 1.47, 1.71 and 1.85 V upon driving overall water splitting, respectively, superior to the performance of current industrial catalysts (200–400 mA cm−2 at 1.8–2.40 V).