Research On Preparation And Dispersion Of Doped Titanium Dioxide Photocatalysis Powders

Due to its excellent photocatalytic activity, low cost,non-toxicity and good stability, etc., the titanium dioxide has received extensive attention. However, the photocatalysis of titanium dioxide can only be activated by ultraviolet light. The ultraviolet light, however, constitutes only about 5 percent of the total energy emitted from the sun, thus to some extent restricting the applications of titanium dioxide. Aiming to enhance the activity of titanium dioxide, this thesis analyzed the photocatalytic degradation effect on methyl orange of titanium dioxide powders prepared by different methods and with different carbon doping amount, sought to determine the optimum carbon doping amount and studied the dispersion of those powders with good photocatalytic activity.The sol-gel method was used to prepare titanium dioxide with modified carbon doping: different amount of tetrabutyl ammonium hydroxide as carbon source was added into butyl titanate and anhydrous alcohol which were used as precursors, and titanium dioxide with modified carbon doping was then prepared by the hydrothermal method; different amount of glucose as carbon source was added into titanium sulfate and deionized water which were used as precursors, and titanium dioxide with modified doping was then prepared by homogenous precipitation-hydrothermal method; different amount of glucose as carbon source was also added into titanium sulfate and urea which were used as precursors, and a series of titanium dioxide powders with different carbon doping were prepared.The prepared powders were then subjected to methyl orange photocatalytic degradation experiment. Under the illumination of mercury lamp (which was used to produce simulated ultraviolet light), the powders were found to have a strong ability to degrade organic matters, which is in line with the photocatalytic characteristic of titanium dioxide; under the illumination of xenon lamp (which was used to produce simulated sun light) for reactions over 6 hours, a portion of the methyl orange solution was degraded by the powders. The powder prepared by homogenous precipitation-hydrothermal method was found to have produced the best photo-catalytic effect, having reached its peak photo-catalytic performance and degraded 32% of the methyl orange solution, when 0.006mol of glucose was added.Using the single-variable method, the thesis tested and studied the dispersion of carbon-doped titanium dioxide powder prepared by homogenous precipitation- hydrothermal method, and analyzed the respective effect of different dispersant and in different amount, different ultrasonic time, and different pH value on the dispersion. The carbon-doped titanium dioxide aqueous solution was found to have the optimum dispersion when the mass ratio of sodium hexametaphosphate to modified titanium dioxide powder to water is 1:50:100, the ultrasonic time is 15min, and the pH value of the solution is 10.