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

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.