Experimental Study Of Nano Tio <sub> 2 </ Sub> Thin Films And Photocatalytic Degradation Of Formaldehyde Gas

Much work has been done in recent years on the photocatalytic treatment of environmental pollutants found in the gas phase for possible application to decontamination, purification, and deodorization of atmospheres. Because TiO2 powder is hard to reclaim, how to prepare good films with high capability is important to the technical application. The TiO2 powder prepared by C3H8/Air CVD method is used to prepare TiO2 thin film using a damp method. This research has a good foreground.The mechanism of the photodegradation of formaldehyde is introduced. The TiO2 thin film on quartz glass is prepared by Liquid Phase Deposition(LPD) method. The thicknesses of the films are determined by a spectrophotometer. The influence factors on the thicknesses such as ultrasonic vibration, times of sedimentation, sedimentation time and concentration of TiO2 colloid are investigated. A mathematical model of sedimentation is set up on the basis of gas adsorption theory.A photocatalytic continual tub reactor is set up. The decomposition of formaldehyde photocatalyed by TiO2 is used as a standard test reaction for the evaluation of efficiency of the TiO2 thin film photocatalyst. The effect factors of degradation of formadehyde such as the style of thin films and the thicknesses are researched. A math model of tub reactor is established with one dimension level. The reaction constant is caculated and is compared with others'.