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.