Study On Preparation And Photocatalytic Performance Of Mixed Metal Oxide Materials

The mixted metal oxides (MMO) material, derived from Layered double hydroxides (LDHs) precursor after thermal treatment under high temperature, has potentially been used in many fields such as catalysis, magnetic, opticals and so on. In the present thesis, we focus on the relationship between the properties and the coupling interaction on the interface of different phases of the MMO material prepared by LDHs precursors under high temperature. And then coupling effects on the photocatalytic properties of the MMO material was studied. Moreover, considering the controversy about LDHs material in the photocatalytic field, we discuss the real cause of the removal of organic dye molecules using pristine LDHs materal.The innovation of this thesis and results are as follows:Firstly, based on the structural feature of the ZnO/ZnAl2O4nanocomposites derived from ZnAl-LDHs precursors, the photocatalytic properties of the ZnO/ZnAl2O4were discussed. After the thermal treatment, the nanoheterjunction structure was formed on the interface between the ZnO and ZnAl2O4phases, and the strong coupling interaction between the two semiconductors made for the separation of photo-induced electron-hole pairs. Therefore, compared with single phase ZnO or similar ZnO/ZnAl2O4fabricated by other physiochemical methods, the ZnO/ZnAl2O4derived from ZnAL-LDHs precursors showed higher photocatalytic activity.Secondly, considering the extensive use of LDHs in the field of removal of organic dye molecules in the solution, the reaction essence was discussed. Representative MgAl-LDHs and ZnCr-LDHs were chosed; then series of experiments under/without visible light irradiation and density functional computation have been done. The real reason for the removal of different organic dye molecoules from the solution with the MgAl-LDHs and ZnCr-LDHs were discussed.