Nanostructured Ni-Doped SnS₂ Photoanode for Efficient Photoelectrochemical Water Splitting

This research explores the impact of nickel (Ni) doping on the performance of SnS2 photoelectrodes in water-splitting applications. A series of Ni-doped SnS2 nanosheets with varying concentrations of Ni (3, 6, and 10 wt %) are synthesized using the hydrothermal method. The photoelectrochemical study reveals a significant ∼22 times increment in the photocurrent density, a decrease in the charge transfer resistance, and an improved IPCE value for 6 wt % Ni-doped SnS2 (6-NSS) as compared to bare SnS2. Mott–Schottky analysis reveals a negative shift in the flat-band potential (VFB) for the 6-NSS photoelectrode, indicating increased band bending and improved charge carrier separation. This enhancement in PEC performance is attributed to the introduction of defects that act as trapping sites for charge carriers, thereby reducing the recombination rate of charge carriers. The BET analysis reveals that 6-NSS has a significantly higher surface area compared to bare SnS2, suggesting the presence of more active sites available for PEC redox reactions. EIS studies support these findings by showing a lower charge transfer resistance in Ni-doped SnS2, indicating improved charge transfer and separation efficiency. The results demonstrate that Ni doping significantly enhances the PEC performance of SnS2, making it a promising photoanode for efficient water-splitting applications.