Cathodic deposition of titanium dioxide (TiO2) from two plating solutions with H2O2 and NaNO3 as their respective oxidants for converting Ti(III) into Ti(IV) are systematically compared. From the electrochemical quartz crystal microbalance (EQCM) and mass loading studies, the deposition solution containing H2O2, denoted as bath A, exhibits a higher rate of TiO2 deposition in comparison with the solution containing NaNO3, denoted as bath B, probably due to the formation of Ti(IV) oxy-hydroxyl species in bath A. However, the surface morphology and crystalline structure of annealed TiO2 deposits are not significantly affected by using different deposition baths. TiO2 deposits have been successfully electroplated onto Ti substrates from both baths under the dual-electrode deposition mode. The surface morphology of TiO2 is significantly influenced by the deposition methods including galvanostatic, potentiostatic, and pulse-rest modes. Finally, uniform porous morphologies of TiO2 in cm2 scale are controllable by varying the pulse-rest deposition variables (e.g., pulse frequency and duty percentage) due to its unique advantages such as excellent adhesion, good uniformity, and controllable particle size of TiO2.
Chi-Chang Hu,Huan-Ching Hsu,and Kuo-Hsin Chang.