Enhanced solar light driven remediation of toxic dye contaminated water using strontium doped BiVO4/gC3N4 with mechanistic insights and kinetic evaluation

In this study, a Sr-doped BiVO 4 /g-C 3 N 4 (Sr@BiVO 4 /g-C 3 N 4 ) heterojunction photocatalyst was successfully synthesized through a facile hydrothermal-assisted thermal treatment route. X-ray diffraction (XRD) analysis confirmed the successful incorporation of Sr 2+ ions into the BiVO 4 lattice, resulting in slight lattice distortion and improved crystallinity. Fourier-transform infrared (FTIR) and UV-Vis diffuse reflectance spectroscopy (DRS) analyses revealed strong interfacial coupling between BiVO 4 and g-C 3 N 4 , along with a noticeable red shift in the absorption edge, leading to a reduced band gap of 2.17 eV. The synergistic effect of Sr doping and heterojunction formation significantly enhanced charge separation efficiency. The optimized Sr-BiVO 4 /g-C 3 N 4 photocatalyst exhibited remarkable photocatalytic performance, achieving up to 99% degradation of crystal violet (CV) dye within 120 min under natural sunlight, outperforming pristine BiVO 4 and its individual components. The superior activity can be attributed to the combined effects of Sr doping, which improves the electronic structure and visible-light absorption, and the formation of a g-C 3 N 4 based heterojunction, which promotes efficient charge transfer and suppresses electron–hole recombination. Overall, this study presents a simple and effective strategy for developing cost-efficient, solar-driven photocatalysts for environmental remediation applications.