A visible-light-driven heterojuncted composite WO₃/Bi₁₂O₁₇Cl₂: Synthesis, characterization, and improved...

Novel visible-light-driven WO₃/Bi₁₂O₁₇Cl₂ heterojuncted photocatalysts with different mass ratios were successfully fabricated by a facile hydrothermal process and were characterized by XRD, UV-Vis DRS, SEM, TEM, HRTEM, XPS, BET, Raman, PL, and ESR techniques. The original morphology of Bi₁₂O₁₇Cl₂ was maintained after the addition of WO₃ nanoparticles and the specific surface area values of WBx composites were obviously enlarged. The intimate contact of both components in HRTEM confirmed the generation of smooth phase interface. These as-prepared samples were subjected to the photocatalytic degradation of dye rhodamine B (RhB) and tetracycline hydrochloride (TC) under visible light irradiation (λ≥420nm). Under identical conditions, WBx composites showed greatly enhanced photocatalytic performance in comparison to bare WO₃ and Bi₁₂O₁₇Cl₂. Especially, the sample WB0.5 exhibited the highest photocatalytic removal outcome over RhB among all tested candidates and owned an apparent rate constant about 73.7, 7.1, 15.8 times of those pure WO₃, Bi₁₂O₁₇Cl₂, and N-doped TiO₂, respectively. The enhancement of photocatalytic capability of composites mainly attributed to the suitable morphology, enlarged specific surface areas, strengthened optical property, and favorable well-aligned straddling band-structures. Active species entrapping experiments confirmed holes and superoxide radicals as major oxidative species, by which, a possible photocatalytic mechanism was primarily proposed.