Interface engineering of N-doped Ni3S2/CoS2 heterostructures as efficient bifunctional catalysts for overall water splitting

Abstract The design and synthesis of non-noble bifunctional electrocatalysts with high efficiency for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is still ongoing for enhanced overall water splitting. Herein, the heterostructure N-doped nickel sulfide/cobalt sulfide (N-Ni3S2/CoS2) catalyst was in situ growth on Ni foams (NF) via an electrochemical deposition method followed by rapidly vulcanizing process at low-temperature. Benefiting from the abundant interface, high conductivity of NF, large electrochemical surface area, N-Ni3S2/CoS2/NF catalyst exhibits excellent activity for both HER and OER. Low overpotentials of 245 and 100 mV can drive a current density of 10 mA cm−2 for OER and HER in 1.0 M KOH. Serving as the bifunctional catalysts, N-Ni3S2/CoS2/NF catalyst delivers the current density of 10 mA cm−2 at a very low cell voltage of 1.56 V in the water splitting reaction.