3D heterogeneous CTF@TiO2/Bi2WO6/Au hybrid supported by hollow carbon tubes and its efficient photocatalytic performance in the UV-vis range

Abstract

Tunable hollow 3D nanostructured materials have attractive photochemical properties and their development is important for improving environmental waste treatment. In this work, a multicomponent 3D heterogeneous CTF@TiO₂/Bi₂WO₆/Au hybrid was prepared and characterized. Calotropis gigantea fiber, a natural biopolymer with a unique hollow structure, was used as a template and carbon source. Gold nanoparticles and Bi₂WO₆ were assembled on the surface of nano-TiO₂, which was supported by the 3D hollow carbon tube fiber (CTF). Benefitting from the controlled assembly of nano-sized Bi₂WO₆ and Au on the CTF, the UV-visible absorption over the entire visible range from 400 to 800 nm was greatly improved. The 3D structure improved the separation of electrons and holes. The UV-vis light decomposition of a series of organic wastewater pollutants, including organic dyes and antibiotics, was efficiently photocatalyzed. With 50 mL of organic pollutants (10 mg L⁻¹) and 20 mg of photocatalyst, when exposed to a 300 W Hg lamp for 10 min, the CTF@TiO₂/Bi₂WO₆/Au photocatalyst achieved degradation rates of 97.9%, 95.1% and 92.4% for methylene blue (MB), rhodamine B (RhB) and levofloxacin (LOF), respectively. After irradiation for 5 min under a 100 W Xe lamp, the degradation rates of MB, RhB and LOF reached 97.3%, 98.4% and 91.2%, respectively. The photodegradation efficiency of the hybrid was markedly higher than those of previously reported TiO₂/Bi₂WO₆/Au and C/TiO₂/Bi₂WO₆ photocatalysts. The synergy of the multicomponent system and the hollow 3D structure dramatically improved its catalytic efficiency. The 3D heterogeneous CTF@TiO₂/Bi₂WO₆/Au hybrid therefore has the potential to be used as a high-efficiency visible light-driven photocatalyst for the degradation of both organic dyes and antibiotics.