Ni loaded SnS hexagonal nanosheets for photocatalytic hydrogen generation water splitting.

Herein we have prepared the Ni-decorated SnS nanosheets with varying concentrations of Ni from 1 to 10 mol% (1, 2.5, 5, and 10 mol%) and studied their various physicochemical and photocatalytic properties. The chemical reduction technique was utilized to load the Ni nanoparticles on SnS nanosheets. The synthesized Ni decorated SnS (denoted as Ni-SnS) was characterized using different spectroscopic techniques such as X-ray diffraction, diffuse reflectance UV-vis and photoluminescence spectroscopy, field emission scanning electron microscopy (FESEM), and field emission transmission electron microscopy (FETEM). XRD revealed the formation of the highly crystalline hexagonal phase of SnS but for nickel loading there is no additional peak observed. Further, the as-prepared Ni-SnS nano-photocatalyst shows absorption behaviour in the visible region, and photoluminescence spectra of the Ni-SnS nanostructures show band edge emission centred at 524 nm, and the peak intensity decreases with Ni loading. The FE-SEM and FE-TEM confirm the formation of hexagonal sheets having evenly distributed Ni nanoparticles of size ∼5-10 nm. BET surface area analysis was observed to be enhanced with Ni loading. The photocatalytic performance of the prepared Ni-SnS nanosheets was evaluated for hydrogen generation water splitting under a 400 W mercury vapour lamp. Among the prepared Ni-SnS nanostructures, the Ni loaded with 2.5 mol% provided the highest hydrogen production , 1429.2 μmol 0.1 g (% AQE 2.32) in four hours, almost 1.6 times that of pristine SnS , 846 μmol 0.1 g. Furthermore, the photocatalytic performance of the catalyst is also correlated with the photoconductivity by measuring the photocurrent. The photoconductivity of the samples is revealed to be stable and the conductivity of 2.5 mol% Ni-SnS is higher 20 times that of other Ni-SnS and pristine SnS catalysts.