A visible-light-driven heterojuncted composite WO 3 /Bi 12 O 17 Cl 2 : Synthesis, characterization, and improved photocatalytic performance.

Novel visible-light-driven WO3 /Bi12 O17 Cl2 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 Bi12 O17 Cl2 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 Bi12 O17 Cl2 . 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 , Bi12 O17 Cl2 , 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.