Phase Transition-Promoted Hydrogen Evolution Performance of MoS2/VO2 Hybrids

In this work, MoS2/VO2 hybrids were synthesized using a two-step hydrothermal method. We used tungsten doping to stabilize the VO2 into the rutile phase at room temperature. The VO2 surface was treated using sulfuric acid to enhance the growth sites for MoS2 as well as the hydrogen evolution reaction active sites for their hybrids. We demonstrate for the first time that the phase transition of VO2 at elevated temperature shows significant effect on hydrogen evolution properties of the heterostructures. Upon the phase transition of VO2, the onset potential and Tafel slope of MoS2/VO2 hybrids were dropped from 188 mV and 93 mV/dec to 99 mV and 85 mV/dec, respectively. This was attributed to the enhanced charge transport efficiency as well as interfacial strain effect on modifying the electronic structure of MoS2.