Preparation And Investigation On Photoelectric Catalytic Activity Of Rare Earth Doped TiO2

Rare earth of Y、Ce、Pr、Sm、Gd、Dy、Ho、Er or Yb doped TiO2were prepared by sol-gel method, and their optical absorption properties、crystal structures、surface morphology and ratio surface area of TiO2powers were characterized by UV-Vis、XRD、 SEM and BET respectively. At the same time, The nickle foam carriers whose surface loaded TiO2are as the anodes, Carbon is as cathode, the ultraviolet light and xenon lamp are as the light sourc, arsenic is as degradation matter for photoelectric catalytic experiment, discussing the catalytic activity of the catalysts. In addition, using density function theory, rare earth (RE=Y、Lu、La、Ce、Pr、Nd、Pm、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb) doped supercycsty Ti8O16were calculated to investgate that how the rare earth doping have an effect on the geometry、the band structure、the density of states and the orbit structure of TiO2.The characterized analysis results of catalysts powers show that:comparing with the pure TiO2, the absorption coefficient of rare earth doped TiO2in ultraviolet region is improved obviously; While in the range of visible light, absorption coefficients of Ce, Pr, Sm, Gd, Ho or Er doped TiO2are enhanced in different degree. But absorption curve of Y, Yb or Dy doped TiO2are almost coincidence with pure TiO2. In addition, Pure TiO2and RE/TiO2are composed of anatase phase; Rare earth doping makes reunion of TiO2powers are more serious, but smaller significantly in particles.The ratio surface area of Gd/TiO2is larger significantly than that of pure TiO2.Basic dyes which is used to detecte arsenic content in water make a standard curve with good near.The results of photocatalytic activity test show that:the amount of As(Ⅴ) is adsorped more by catalysts than that of As(Ⅲ). The adsorption amount of the same catalyst but loading in different amount is different when As(Ⅲ) is adsorpted. But the adsorption amount is proportional to load amount. In addition, the oxidation ability under the ultraviolet light of rare earth doped TiO2are stronger than pure TiO2, at the same time, the oxidation ability of Y/TiO2and Gd/TiO2are the best.In the condition that the catalyst loading are basically the same, the As(Ⅲ) adsoption amount and the arsenic removal efficiency of RE/TiO2are higher than that of pure TiO2. Sm/TiO2and Ce/TiO2among all catalysts are the best. The photoelectric catalytic oxidation ability of Er/TiO2is superior obviously to the photocatalytic oxidation, The oxidation amount of the former is almost two times than that of the last. The reason is that simple compositcan of the photogenerated electrons-holes is inhibited by the applied voltage.The analysis results of caculation show that:Y, La, Gd, Lu, Ce, Eu, Yb or Tb doping can promote the photocatalytic activity of TiO2, while too much of Pr, Nd, Pm, Sm, Dy, Ho, Er or Tm may decrease its photocatalytic activity, because of forming more orbitals between valence band top and conduction band bottom, which will act as combing centers for electronics and holes, therefore the concentration of them need to be limited to a smaller range, the theoretical results agree with the experimental results and coincide with the external electronic obital arrangement laws of rare earth elements in the periodic table.It is clear that suitable RE/TiO2is more powerful than pure TiO2and should possesses higher photocatalytic activity than pure TiO2.