title: Synthesis and visible light photocatalytic properties of polyoxometalate-thionine composite films immobilized on porous TiO2 microspheres.
abstract: Multilayer films (PW(12)-TH)(n) (PW(12)=PW(12)O(40)(3-), TH=thionine) were immobilized on porous anatase TiO(2) microspheres by layer-by-layer (LbL) self-assembly method. The porous structure of TiO(2) was confirmed by transmission electron microscopy (TEM). Scanning electron microscopy (SEM) showed that TiO(2) template particles had a round shape with an average diameter of 250 nm. The composite films were characterized by FTIR spectroscopy, UV diffuse reflectance spectroscopy and XRD spectroscopy. The results confirmed the successful immobilization of (PW(12)-TH)(n) composite films onto TiO(2) microspheres, and the growth of PW(12)-TH layer pair was uniform. SEM and TEM were also used to characterize the morphology. When PW(12)-TH composite films were assembled on the template, the surface became rougher with the increasing number of layer pair. The lattice fringe of TiO(2) became weaker when immobilized (PW(12)-TH)(n). The photocatalytic properties of the microspheres toward a rhodamine B (RhB) solution were investigated under visible light irradiation. The combination of TiO(2) and PW(12) showed an excellent photocatalytic performance. Both TH sensitization and PW(12) adsorption played important roles during the process of photocatalysis. Moreover, the catalytic property and reusability of as-prepared catalyst were relevant to the number of PW(12)-TH bilayer. The kinetics of the photodecomposition to rhodamine B followed the first-order reaction.
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, PR China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Yang
authors.forename: Shuiying
authors.initials: S
authors.lastname: Gao
authors.forename: Hongfang
authors.initials: H
authors.lastname: Li
authors.forename: Rong
authors.initials: R
authors.lastname: Cao
mesh_terms: D002384:Catalysis; D007700:Kinetics; D008027:Light; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008863:Microspheres; D010316:Particle Size; D010640:Phenothiazines / Q000737:chemistry*; D010782:Photolysis; D016062:Porosity; D012235:Rhodamines / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014025:Titanium / Q000737:chemistry*; D017973:Tungsten Compounds / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods; D014961:X-Ray Diffraction; D000099294:Polyoxometalates
chemical_list: D010640:Phenothiazines; D012235:Rhodamines; D014025:Titanium; D017973:Tungsten Compounds; D014874:Water Pollutants, Chemical; C102296:polyoxometalate I; D000099294:Polyoxometalates; C009495:titanium dioxide; C029773:rhodamine B; C009469:thionine