Sol-gel-derived photosensitive TiO2 and Cu/TiO2 using homogeneous hydrolysis technique

Titania and copper-loaded titania were synthesized by an improved sol-gel method using a homogeneous hydrolysis technique. Unlike the conventional sol-gel procedure that added water directly, the esterification of anhydrous butanol and glacial acetic acid provided the hydrolyzing water. In addition, acetic acid also served as a chelating ligand to stabilize the hydrolysis-condensation process and minimize the agglomeration of titania. Fourier transform infrared spectra confirmed the presence of bidental ligand. The sol was dried, then calcined at 500°C to remove organics and transformed to anatase titania. Transmission electron microscopy revealed that the titania particles were uniform, and the particle size ranged from 10 to 25 nm. The band gaps of TiO2 and Cu/TiO2 ranged from 3.01 to 3.17 eV based on the diffusive reflective ultraviolet-visible spectrometry. X-ray photoelectron spectroscopy analysis showed a positive shift of binding energy of Ti2p3/2 and a negative shift of Cu 2p3/2 in Cu/TiO2. The redistribution of electric charge is due to the Schottky barrier of Cu and TiO2.