MoS2 vertically grown on graphene with efficient electrocatalytic activity in Pt-free dye-sensitized solar cells

Abstract In this report, MoS 2 nanosheets grown vertically on reduced graphene oxide (MoS 2 @RGO) were successfully prepared via a facile hydrothermal process, and then worked as counter electrode (CE) in dye-sensitized solar cells (DSSCs). The MoS 2 @RGO materials revealed enhanced electrocatalytic activity and stable chemical property for accelerating the reduction of I − /I 3 − redox couple. Cyclic voltammograms (CV) showed that the peak current density ( J A ) and peak spacing ( E pp ) of MoS 2 @RGO CE were smaller than Pt, MoS 2 , and RGO in DSSCs, owing to the superior carrier transfer properties of graphene, abundant catalytic active sites and low resistance of MoS 2 @RGO. Furthermore, the power conversion efficiency (PCE) of MoS 2 @RGO CE reached 6.82%, which is higher than that of Pt CE (6.44%). Electrical impedance spectroscopy (EIS) and tafel polarization were also investigated to demonstrate positive synergetic effect between MoS 2 and RGO, as well as efficient electrocatalytic performance in Pt-free DSSCs.