Synthesis of Zn-doped MoS2-graphene heterostructure for efficient water splitting

The demand of renewable energy increases day by day as we progress towards near future. Here we report new type of 2D heterostructures which show superior electrochemical performance towards both hydrogen and oxygen evolution reaction. We demonstrate the synthesis of heterostructure by mixing graphene oxide, Mo-salt, and thiourea via hydrothermal method at 180 oC for 12 hrs. The heterostructure has lots of defected area which enhanced the active sites for both reactions, was revealed by SEM, TEM characterization. Later on, we have performed density functional theory calculation, which demonstrate that the activity mainly comes from sulfur and zinc sites of this heterostructure represented by Gibbs free energy diagram. The density of states calculation shows that the presence of zinc in MoS2-graphene heterostructure increases the electron density throughout the whole structure. Finally, the band structure calculation reveals that zinc reduces the band gap for heterostructure and increases the water splitting capacity into hydrogen and oxygen.