Wet-chemical synthesis of MoS2/graphene heterostructures with enhanced electrocatalytic performance: Substantiating the role of the covalent bond

Two-dimensional (2D) heterostructures represent an attractive novel field of research, aimed at combining properties of various 2D materials by formation of ordered assemblies. In this context, graphene offers great electrical conductivity and is widely used as a versatile platform for novel hybrids. Molybdenum disulphide (MoS₂), unlike graphene, is a catalytically active semiconductor, known for its ability to catalyse reactions, such as water-splitting hydrogen production. Although most research to date has focused on non-covalently bonded assemblies, introducing strong chemical bonds between these two materials could provide enhanced synergistic benefits. In present paper we have designed a liquid-phase strategy for controllable fabrication of covalent 2D graphene/MoS₂ heterostructure. The covalent heterostructure exhibited improved electronic conductivity and enhanced hydrogen production performance as compared to its non-covalent analogue, highlighting the importance of chemical approaches to 2D hybrid heterostructure production.