New Developed (Ag)-La$$_2$$O$$_3$$-Ce$$_4$$O$$_7$$-ZnO Photocatalytic Active Composites for Textile Dyes Degradation

Abstract

New La₂O₃-Ce₄O₇-ZnO photocatalytic active composites were synthesized using Pluronic-assisted co-precipitation route, followed by calcination at 450° C. The silver doping of the prepared La₂O₃-Ce₄O₇-ZnO material was performed by impregnation with aqueous solution of AgNO₃. The average crystallites size 3 nm and 39 nm for Ce₄O₇ and ZnO phases were estimated by PXRD analysis. The XPS study determined that the La3d_5/2 peak is positioned at 834.1 eV and corresponds to La₂O₃. The binding energy of the Ag3d_5/2 peak of the Ag-La₂O₃-Ce₄O₇-ZnO powder is at 367.2 eV and the amount of the silver on the surface is 0.8 at%. The obtained values of the modified Auger zinc and silver parameter are 2010.5 eV and 724.4 eV and correspond to Zn²⁺ and Ag²⁺ oxidation states, respectively. The silver doping enhances the photocatalytic efficiency of La₂O₃-Ce₄O₇-ZnO sample for degradation of Reactive Black 5 dye (78%) at 150 min UV irradiation compared to that of the undoped sample (52%). The undoped sample demonstrates the higher photocatalytic ability for degradation of Malachite Green dye (degree of degradation at 150 min – 80%) in comparison with Reactive Black 5 dye (52%).