Ordered mesostructured Cu-doped TiO2 spheres as active visible-light-driven photocatalysts for degradation of paracetamol

Abstract

We combined the wet chemical route with an aerosol-assisted self-assembly (AASA) process to prepare ordered mesostructured Cu-doped TiO2 spheres (Cu–TS) with high surface area and crystallinity for the visible-light photocatalytic degradation of paracetamol. The obtained photocatalysts were characterized by scanning electron microscopy, transmission electron microscopy, ultraviolet–visible spectroscopy, N2 adsorption isotherms, X-ray diffraction, and X-ray photoelectron spectroscopy. Cu–TS exhibits a shift in the absorption threshold toward the visible spectrum. No measurable CuO diffraction peaks were detected in the anatase Cu–TS, indicating the Cu2+ ions were homogeneously introduced into crystalline TiO2 frameworks. This result was also confirmed by the similarity of the Cu/Ti ratio in the bulk and on the surface. As the Cu concentration increased, CuO aggregates appeared and favorably affected the crystallization of TiO2 into the rutile structure. Under visible light irradiation, Cu–TS exhibited a much higher photocatalytic activity for the degradation of paracetamol compared with that of undoped TiO2. For the Cu–TS photocatalytic system, the aromatic by-products did not accumulate, and oxamic acid and ammonium were the predominant end products. Even after 10 repeated runs, the recycled Cu–TS showed good photodegradation activity.