Research Of Ag And Ce Doped TiO₂ Nano-photocatalyst

The development and application of semiconductor TiO₂ photocatalystare introduced in this thesis. Photocatalysis mechanism and factors thatinfluence preparation and photocatalysis activity are reviewed.TiO₂ has limitation such as wide valence gap, narrow photo adsorbedwavelength, and high semiconductor current recombination ratio. In orderto change its properties, by sol-gel method and diping to prepare Ag and Cedoped TiO₂/silica gel. The photocatalysis activity of new photocatalyst isinvestigated with XRD and SEM.After Ag is doped, it is founded that TiO₂ particle diameter increased,transformation temperature lowered and rutile crystal appeared at 550℃.Due to Ag doped, photo adsorption, transmission and capture state ofelectron that generated by photo are increased. And for Ce dopedcatalyst,TiO₂ transformation from anatase to rutile is restrained, transfertemperature increased;it is good for near ultraviolet adsorption andelectron-cavity separated effectively. According to the experiment ofphotocatalysis, Ag and Ce doping improve the photocatalytic activityprominently. With suitable doping quantity, calcinations temperature,lighting time, etc, the catalyst can reach the best photocatalysis capability.Base on the results, TiO₂ particle diameter in the prepared catalyst isabout 10-20nm.Ag and Ce doped catalyst have better activity than P25 andno doped catalyst. Photocatalyst solidifing solves the disadvantage ofpowder state catalyst such as separating cycling difficulty.