Enhanced electrocatalytic performance of nickel diselenide grown on graphene toward the reduction of triiodide redox couples

The promising activity of nickel diselenide (NiSe(2)) towards electrocatalysis has made it especially attractive in energy conversion fields. However, NiSe(2) with high electrocatalytic performance always requires complicated fabrication or expensive conductive polymers, resulting in the scale-up still being challenging. Herein, we introduce a simple and cost-effective synthesis of NiSe(2) dispersed on the surface of graphene (NiSe(2)/RGO NPs). NiSe(2)/RGO NPs exhibited enhanced electrocatalytic performance and long-term stability for the reduction reaction of triiodide redox couples in dye-sensitized solar cells (DSSCs). Leveraging the advantageous features, the DSSC fabricated with NiSe(2)/RGO NPs as CE had a smaller charge-transfer resistance (R(ct)) value and higher short-circuit current density and fill factor than naked NiSe(2) NPs. Additionally, NiSe(2)/RGO NPs achieved a PCE of 7.76%, higher than that of pure NiSe(2) (6.51%) and even exceeding that of Pt (7.56%). These prominent features demonstrated that the NiSe(2)/RGO NPs in this work are a promising cheap and efficient electrocatalyst to replace state-of-the-art Pt.