Graphene-templated growth of MoS2-Ni3S2 heterostructures as efficient electrocatalysts for overall water splitting

Due to the advantages of large specific surface area, high mass transfer efficiency and easy access to active sites, two dimensional (2D) nanomaterials provide a great opportunity for the construction of new versatile electro-catalysts with superior properties. Herein, a graphene-templated growth of MoS2-Ni3S2 heterostructure with porous structure is successfully prepared on the Ni foam (MoS2/Ni3S2@G/NF) by one pot hydrothermal method. The electronic structure and surface properties of 2D chalcogenides are modified by heterogeneous interface and component engineering, so as to prepare a high-performance transition metal composite catalytic electrode for electrochemical reaction. The optimized MoS2/Ni3S2 @G/NF shows excellent bifunctional activity and durability in alkaline medium. It only needs 53 mV and 265 mV overpotential to reach 10 mA cm-2 current density of HER and 20 mA cm-2 current density for OER, respectively. When the composite is used as an advanced electro-catalyst for water splitting, the 1.47 V voltage required to achieve a current density of 10 mA cm-2, which is better than the most non-noble metal electrocatalysts. The heterostructures between MoS2, Ni3S2 and graphene are conducive to the synchronous chemical adsorption of hydrogen and oxygen-containing intermediates, which can improve the catalytic activity of overall water splitting.