title: Photochemically deposited nano-Ag/sol-gel TiO2-In2O3 mixed oxide mesoporous-assembled nanocrystals for photocatalytic dye degradation.
abstract: This work focused on the improvement of the photocatalytic activity for Congo Red (CR) azo dye degradation of mesoporous-assembled 0.95 TiO2-0.05 In2O3 mixed oxide photocatalyst (with a TiO2-to-In2O3 molar ratio of 0.95:0.05) by loading with Ag nanoparticles. The mesoporous-assembled 0.95TiO2-0.05In2O3 mixed oxide photocatalyst was synthesized by a hydrolytic sol-gel method with the aid of a structure-directing surfactant, prior to loading with various Ag contents (0.5-2 wt.%) by a photochemical deposition method. The optimum Ag loading content was found to be 1.5 wt.%, exhibiting a great increase in photocatalytic CR dye degradation activity. The 1.5 wt.% Ag-loaded 0.95TiO2-0.05In2O3 mixed oxide photocatalyst was further applied for the CR dye degradation in the presence of water hardness. Different types (Ca2+ and Ca2+ -Mg2+ mixture) and concentrations (200 and 500 mg/l) of water hardness were investigated. The results showed that the water hardness reduced the photocatalytic CR dye degradation activity, particularly for the extremely hard water with 500 mg/l of Ca2+ -Mg2+ mixture. The adjustment of initial solution pH of the CR dye-containing hard water to an appropriate value was found to improve the photocatalytic CR dye degradation activity under the identical reaction conditions.
authors.affiliation: Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A(*)STAR), 3 Research Link, Singapore 117602, Singapore. Electronic address: sreethawongt@imre.a-star.edu.sg.
authors.forename: Thammanoon
authors.initials: T
authors.lastname: Sreethawong
authors.affiliation: Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan. Electronic address: wonone@hotmail.com.
authors.forename: Supachai
authors.initials: S
authors.lastname: Ngamsinlapasathian
authors.affiliation: Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Yoshikawa
mesh_terms: D002384:Catalysis; D004396:Coloring Agents / Q000737:chemistry*; D007204:Indium / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D055668:Photochemical Processes; D012834:Silver / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D004396:Coloring Agents; D007204:Indium; C009495:titanium dioxide; D012834:Silver; C047711:indium oxide; D014025:Titanium
keywords: Ag loading; In(2)O(3); Mixed oxide; Photocatalytic dye degradation; TiO(2); Water hardness