One-step sol-gel fabrication of TiO2/(CuO+Cu2O) photocatalysts

Abstract

Photocatalytically active TiO2+CuO+Cu2O composite structures on copper foil and pre-oxidized copper grids were fabricated using a novel one-step sol-gel synthesis. The sol used included titanium tetraisopropoxide, ethylene glycol monomethyl ether, and nitric acid. Scanning electron microscopy of the composites synthesized upon calcination of the dip-in deposited sol at 400–500 °C demonstrated them to consist of a granular oxide surface layer with a thickness up to 200 nm penetrated by CuO whiskers as long as up to several micrometers. Copper oxides (CuO and Cu2O), as well as titanium dioxide (TiO2) in the anatase phase, were registered by X-ray diffraction analysis. High photocatalytic activity with respect to the test pollutant Rhodamine B in an aqueous solution under UV-activation was observed. The developed surface morphology combined with an efficient separation of photogenerated charge carriers at the TiO2/(CuO or Cu2O) heterojunctions is considered to be responsible for the observed photocatalytic activity. The proposed one-step fabrication of catalytically active materials immobilized on a substrate is promising for improving existing water and air purification systems.