Research On Preparation Technology Of Advanced High-Efficiency Photocatalytic Thin Films

Titanium dioxide（Ti O₂） is one of the most commonly used photocatalytic materials. But it’s disadvantages of easy loss and low utilization rate of sunlight limits its practical application greatly. In order to improve the practical property of Ti O₂, in this study the high efficiency doped Ti O₂ photocatalytic glass films were prepared by the sol-gel method with the glass as carrier.Firstly, the four technological parameters including the mole ratio of H2 O and Ti, calcination temperature, calcination time and aging time for preparing the Ti O₂ photocatalytic glass films were optimized. Secondly, the Ti O₂ photocatalytic glass films were modified to enhance their sunlight photocatalytic activity. Herein the Ti O₂ photocatalytic glass films were doped with metal element iron（Fe）,nonmetal element nitrogen（N）, and co-doped with Fe and N simultaneously. The optimal doping ratios of three doping methods were achieved by photocatalytic degraded indoor formaldehyde under sunlight. In addition,techniques of X-ray diffraction（XRD）, Scanning electron microscopy（SEM） and Energy-dispersive X-ray spectroscopy（EDS）, Transmission electron microscopy（TEM）, UV-vis spectrum were employed to examine the effects of Fe and N elements on morphology, structure and optical characteristics of Ti O₂ thin films. The results showed that the modification effect of Fe/N co-doping was the best, and the optimal doping mole ratios of Fe and N were 1% and 25%.In order to explore the application value of the doped Ti O₂ photocatalytic glass films, the photocatalytic degradation efficiencies of indoor formaldehyde, ammonia and benzene by the Fe/N co-doped Ti O₂ photocatalytic glass films were investigated simulating the actual indoor polluted air. Also, the photocatalytic stability of the doped Ti O₂ photocatalytic glass films of was investigated. The results show that the Fe/N co-doped Ti O₂ photocatalytic glass film can remove the indoor air pollutants effectively, and this photocatalyst exhibits an excellent stability, suggesting the value of applications.Finally, the photocatalytic degradation reaction kinetic models were fitted to analyze reaction mechanism and influence mechanisms of the photocatalytic degradation from the four impact aspects which were the types of photocatalysts, the types of pollutants, the amount of photocatalysts and the initial concentration of pollutants. The kinetics of photocatalytic degradation conformed to the pseudo-first-order model, the degradation of the pollutants characterized by chemical reactions occuring on the surface of the catalyst.