Visible Light Active Ni-doped SnS₂/g-C₃N₄ type-Ⅱ Heterojunction for Enhanced Photoelectrochemical Performance

This study presents an effective strategy to enhance the PEC performance of bare SnS2 by incorporating Ni into SnS2 nanosheets and then forming type-II heterojunction with g-C3N4 nanosheets. The Ni-SnS2/g-C3N4 photoanode shows a significantly enhanced photocurrent density of around 3.5 mA/cm2, which is about 1.4 times higher than Ni-SnS2 and ~11.6 times greater than SnS2 at 1.0 V with respect to Ag/AgCl. The Ni-SnS2/g-C3N4 photoanode achieves an incident photon-to-current conversion efficiency (IPCE) of approximately 16.1%, whereas Ni-SnS2 and SnS2 exhibit IPCE values of ~13.0% and ~0.6%, respectively. The enhanced PEC performance of Ni-SnS2/g-C3N4 is attributed to the extended optical absorption spectrum and enhanced photocatalytic activity. The synergistic effect of Ni-doping and type-Ⅱ heterojunction of Ni-SnS2 with g-C3N4 facilitates efficient electron migration from g-C3N4 to Ni-SnS2, which minimizes recombination losses.