Ultralong NiSe nanowire anchored on graphene nanosheets for enhanced electrocatalytic performance of triiodide reduction.

Like their higher-dimensional counterparts, nanowire structures possess desirable features for electrocatalysis applications. In this study, ultralong NiSe nanowires (of diameters 50-150 nm and length 20 μm) were successfully anchored onto graphene nanosheets (NiSe NW/RGO). The NiSe nanowires were coated with a thick (∼10 nm) disordered surface replete with active sites. Benefiting from the fast charge-transfer channels and plentiful electroactive sites on the NiSe nanowires, in synergy with the high electroactive surface and electrical conductivity of the graphene nanosheets, the optimized NiSe NW/RGO exhibited a remarkably higher electrocatalytic activity than NiSe nanowires and typical Pt counter-electrodes (CEs). NiSe NW/RGO also exhibited the low charge-transfer resistance of 1.64 Ω cm and delivered a higher power conversion efficiency (PCE = 7.99%) than Pt CEs (PCE = 7.76%).