Improved visible-light-driven photocatalytic activity of rutile/titania-nanotube composites prepared by microwave-assisted hydrothermal process

Abstract

This study demonstrates a facile approach based on microwave irradiation for the preparation of rutile/titania-nanotube composites that exhibit highly efficiency in visible light induced photocatalysis. The obtained nanocomposites were characterized using XRD, Raman, FESEM, TEM, N2 physisorption isotherms at 77K and UV–vis DRS techniques. The results show that the nanocomposites exhibit multilayer-wall morphologies with open-ended cylindrical structures. The presence of the rutile phase in the titania nanotubes enhanced the light-harvesting efficiency in photocatalytic reactions. By H2-thermal treatment, the optical absorption of the nanocomposite extends to the visible light region up to 600nm. It is believed that thermal-treatment gives rise to create active surface oxygen vacancies, which are responsible for visible light absorption and the promotion of electrons from the localized states to the conduction band. The catalytic results revealed that the nanocomposites exhibited higher photocatalytic activities toward the decomposition of nitric oxide and the degradation of methylene blue compared with commercial P25 TiO2.