Photocatalytic degradation of gallic acid over CuO-TiO₂ composites under UV/Vis LEDs irradiation

Coupling TiO₂ with narrow band gap semiconductors has been a strategy to obtain visible light active photocatalysts. In this work we present, the characterization and photocatalytic results of high-loaded CuO-TiO₂ composites prepared by impregnation of TiO₂ powder (Evonik, P25) with copper acetate followed by calcination. The resulting composite materials were characterized by X-ray diffraction, nitrogen adsorption/desorption, UV-vis diffuse reflectance, scanning electron microscopy, X-ray photoelectron spectroscopy and time-resolved microwave conductivity. The photocatalysts were used to degrade gallic acid by using low power ultraviolet and visible light emitting diodes (UV-LED and Vis-LED) as light sources. According to the results, the photocatalytic degradation of the pollutant was efficiently converted to several intermediate products and partially mineralized to CO₂ by using visible light. These results were explained in terms of an enhancement of the optical and electronic properties of TiO₂ by the presence of Cu₂O and CuO phases.