Improved photocatalytic activity of nano CuO-incorporated TiO₂ granules prepared by spray drying

4wt% CuO-96wt% TiO₂ granules were prepared by a spray drying process. The microstructure and optical property of CuO-TiO₂ granules were studied. The results indicate that copper existed in the form of CuO. The spray dried granules possess spherical geometry and smooth surface with grain size in the range of 40-80μm. CuO-TiO₂ has a relatively smaller E_g value (2.85eV) than TiO₂ (3.17eV). The photocatalytic property of CuO-TiO₂ granules was investigated by degradation of a model pollutant (the azo dye methyl orange) under the irradiation of the xenon lamp equipped with a band pass filter of 365nm. The CuO-TiO₂ spray-dried granules degrade about 10% more MO than TiO₂ spray-dried granules under UV irradiation within the same time. The XPS spectra suggested that Cu²⁺ and reduced copper species were coexistent in reacted CuO-TiO₂ photocatalyst. The improvement of photocatalytic activity for CuO-TiO₂ was mainly attributed to effective separation of photo-generated electron-hole pairs in the presence of CuO.