One step room temperature photodeposition of Cu/TiO2 composite films and its conversion to CuO/TiO2

Cu/TiO2 composite films were prepared at low temperature on glass substrates by a photodeposition method. Films were deposited by irradiating the substrate while in contact with an aqueous TiO2 suspension containing copper(II) nitrate and ethanol. Cu/TiO2 composite films of 500 nm in thickness were deposited at room temperature after a short irradiation time (15 min) with a 125 W mercury vapour lamp. According to scanning electron microscopy observations, the obtained films were homogeneous and porous. Energy dispersive X-ray spectroscopy analysis revealed a 3:1 Cu:Ti atomic ratio. Grazing angle X-ray diffraction analysis showed that the films contained Cu and TiO2 as major components and Cu2O as a minor component. Heat treatment at 400 °C in air for a period of 3 h transformed the initial material into a CuO/TiO2 composite, improved the adhesion to the substrate and favoured a more regular distribution of copper oxide according to backscattering micrographs.