Abstract
This work demonstrates that the microstructure of TiO 2 film can be designed and controlled by adjusting the temperature and cycle number of cathodic deposition in a solution containing TiCl 3 and NaNO 3 . The redox interactions between TiCl 3 and NO 3 - are investigated by in situ ultraviolet-visible (UV-vis) absorption spectroscopy. Linear sweep voltammetry (LSV) is employed to study the NO 3 - reduction and to clarify the deposition behavior of TiO 2 in the designed plating solution. The decrease in TiO 2 deposition rate with the TiO 2 thickness may be due to the poor electron conductivity of TiO 2 depressing the generation rate of OH - from the NO 3 - reduction. The morphology and size of TiO 2 aggregates are strongly influenced by varying the deposition temperature from 5 to 50 °C and a maximal rate of TiO 2 deposition is obtained at 25-35 °C. TiO 2 deposited at 25 °C is the roughest with a roughness factor (Ra) of ca. 67 nm. This study provides a useful method to control the morphology and deposition rate of TiO 2 film for practical photoelectrochemical applications. © 2010 Elsevier Ltd.