Novel S-scheme derived Mo–Bi2WO6/WO3/Biochar composite for photocatalytic removal of Methylene Blue dye

Abstract

Presently, the distinct charge transport and interface interaction of the S-scheme heterojunction has garnered significant interest. Herein, a S-scheme-based charge transportation Mo-doped Bi₂WO₆/WO₃/Biochar heterojunction was synthesized in situ using a coprecipitation technique to improve methylene blue adsorption and photocatalytic reactive oxygen species production. The doped Mo altered the band gap of Bi₂WO₆ to increase light absorption, which can facilitate electron-hole separation and transfer. Likewise, the S-scheme band structure improved sunlight utilization, enhanced the reduction and oxidation power of photogenerated electrons, and boosted charge carrier separation and transfer. Thus, due to the synergetic impact of doping and the S scheme band structure, the photocatalysts efficiently eliminated Methylene blue up to 87.5 % in 30 min of photoirradiation. Fabricated heterojunction Mo–Bi₂WO₆/WO₃/Biochar photocatalyst have highest Kapp values 0.02816 min⁻¹ while Mo–Bi₂WO₆/WO₃, Mo–Bi₂WO₆, Bi₂WO₆, and WO₃ photocatalysts have 0.02816, 0.02273, 0.01527, 0.00643, and 0.00735 min⁻¹, respectively which was 4.38 times greater than pristine Bi₂WO₆. The study offers a novel perspective for the in-situ production of S-scheme heterojunction with doping to remove different types of contaminants.