NiCo-LDHs derived NiCo2S4 nanostructure coated by MoS2 nanosheets as high-efficiency bifunctional electrocatalysts for overall water splitting

Abstract To develop a high efficiency non-precious electrocatalyst with cost-effective and good stability for Hydrogen Evolution Reaction (HER) and Oxygen Evolution Reaction (OER) still remains a formidable challenge. Herein, we present a new hydrothermal method based on integrating NiCo-Layered Double Hydroxides (NiCo-LDHs) with Molybdenum Sulfide (MoS2) to develop a three-dimensional (3D) MoS2/NiCo2S4 nanostructure supported on Nickel Foam (NF). To optimize the interfacial structure and promote the catalytic activity, the molar ratio of MoS2/NiCo2S4 is used to regulate the hybrids' nanostructure. The optimal MoS2/NiCo2S4/NF is obtained as the molar ratio reaches 20%, which can be used as a bifunctional electrocatalyst with ultrahigh electrocatalytic property for HER and OER in alkaline electrolyte. As expected, the optimize MoS2/NiCo2S4/NF shows an overpotential as small as 90 and 220 mV at 10 mA cm−2 for HER and OER in 1 M KOH. Additionally, an electrolyzer is assembled where MoS2/NiCo2S4/NF serves as anode and cathode electrode, the current densities achieve 10 mA cm−2 only need a cell potential of 1.49 V. This works can provide a new window for designing high-efficiency and cost-effective non-precious bifunctional catalysts based on LDHs as precursors for HER and OER in the future.