The XRD patterns of different calcined layered double hydroxides(CLDH) and their ultraviolet absorbing and screening properties have been investigated. It has been found that a calcined layered double hydroxide(CLDH) ...The XRD patterns of different calcined layered double hydroxides(CLDH) and their ultraviolet absorbing and screening properties have been investigated. It has been found that a calcined layered double hydroxide(CLDH) containing zinc is very effective in absorbing and screening ultraviolet radiation. The crystal structure of a CLDH containing zinc is similar to that of ZnO and is not related to the crystal structure of Al 2O 3. It is not a simple combination of zinc oxide and aluminium oxide but a calcined layered double hydroxide in which part of the Zn 2+ cations is replaced by Al 3+ cations.展开更多
The perovskite(ABO 3) type oxides have a photocatalytic activity that can be characterized with decolorization of some organic dyes under irradiation of mercury lamp. The experimental results show that the photocataly...The perovskite(ABO 3) type oxides have a photocatalytic activity that can be characterized with decolorization of some organic dyes under irradiation of mercury lamp. The experimental results show that the photocatalytic activity of ABO 3 increases with increasing atomic number of atom B(Ti—Co) when A site atom keeps constant. It is connected with the rise of Allred Rochow electronegativity of atom B, the decrease of ABO 3 energy gap(energy defference between the filled p bands of O 2- and the unoccupied 3 d band of neighboring atom B) and the increase of the third atomic ionizaton potentials of atom B. It has been also proved that the photocatalytic activity of ABO 3 compounds increases with increasing χ AR of atom A(Ca, Cd, Pb).展开更多
文摘The XRD patterns of different calcined layered double hydroxides(CLDH) and their ultraviolet absorbing and screening properties have been investigated. It has been found that a calcined layered double hydroxide(CLDH) containing zinc is very effective in absorbing and screening ultraviolet radiation. The crystal structure of a CLDH containing zinc is similar to that of ZnO and is not related to the crystal structure of Al 2O 3. It is not a simple combination of zinc oxide and aluminium oxide but a calcined layered double hydroxide in which part of the Zn 2+ cations is replaced by Al 3+ cations.
文摘The perovskite(ABO 3) type oxides have a photocatalytic activity that can be characterized with decolorization of some organic dyes under irradiation of mercury lamp. The experimental results show that the photocatalytic activity of ABO 3 increases with increasing atomic number of atom B(Ti—Co) when A site atom keeps constant. It is connected with the rise of Allred Rochow electronegativity of atom B, the decrease of ABO 3 energy gap(energy defference between the filled p bands of O 2- and the unoccupied 3 d band of neighboring atom B) and the increase of the third atomic ionizaton potentials of atom B. It has been also proved that the photocatalytic activity of ABO 3 compounds increases with increasing χ AR of atom A(Ca, Cd, Pb).
