title: Enhanced photocatalytic degradation of phenol over anatase TiO2in neutral water on addition of iron(iii) substituted polyoxotungstate.
abstract: PW12O40-type polyoxometalates have been widely used as electron mediators of TiO2photocatalysis for organic degradation in water, but they are stable only at pH 1-2, which greatly limits their application for water treatment. Herein we report an iron(iii)-substituted PW11O39(PW11Fe) capable of mediating the photocatalytic degradation of phenol and 2,4-dichlorophenol in an aerated aqueous suspension of anatase TiO2at pH 2.0-7.2. As the initial concentration of PW11Fe or the initial pH of the suspension increased, the rate of phenol degradation increased, and then decreased. A maximum reaction rate was achieved at 2.0 mM PW11Fe and pH 5.5, which was 3.9 times higher than that measured without PW11Fe. In all cases, the rates of phenol degradation were of the first order in phenol, implying the recycling behavior of PW11Fe. Through electrochemical measurement, a possible mechanism is proposed, which involves the interfacial electron transfer from the irradiated TiO2to PW11Fe, and the reduction of O2by the reduced PW11Fe. This would improve the efficiency of the charge separation of TiO2, and consequently increase the rate of phenol degradation at interfaces.
authors.affiliation: State Key Laboratory of Silicon Materials and Department of Chemistry, Zhejiang University, Hangzhou 310027, China. xuym@zju.edu.cn.
authors.forename: Linlin
authors.initials: L
authors.lastname: Hao
authors.affiliation: Ningbo Institute of Technology, Zhejiang University, Ningbo 315100, P. R. China.
authors.forename: Meiqin
authors.initials: M
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Silicon Materials and Department of Chemistry, Zhejiang University, Hangzhou 310027, China. xuym@zju.edu.cn.
authors.forename: Xianqiang
authors.initials: X
authors.lastname: Xiong
authors.affiliation: State Key Laboratory of Silicon Materials and Department of Chemistry, Zhejiang University, Hangzhou 310027, China. xuym@zju.edu.cn.
authors.forename: Yiming
authors.initials: Y
authors.lastname: Xu
mesh_terms: D002384:Catalysis; D055664:Electrochemical Techniques; D005290:Ferric Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008027:Light; D010636:Phenols / Q000737:chemistry*; D055668:Photochemical Processes; D014025:Titanium / Q000737:chemistry*; D017973:Tungsten Compounds / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D018508:Water Purification
chemical_list: D005290:Ferric Compounds; D010636:Phenols; D017973:Tungsten Compounds; D014867:Water; C009495:titanium dioxide; D014025:Titanium