Preparation And Photocatalytic Activity Of（Fe（Ⅲ）-8-hydroxyquinoline-5-carboxylic Acid）/TiO₂

TiO₂ has been widely used in photocatalysis because its non-toxic harmless,better chemical and thermal stability,inexpensive and easy to be obtained,high photocatalytic efficiency.However,TiO₂ also has defects such as it can only absorb ultraviolet light due to its wide band gap.Furthermore,the photogenerated electrons and holes of TiO₂ are easy to re-combine.These limit the application of TiO₂ greatly.Dye sensitization is one of the effective methods to broaden the range of light absorption and reduce the recombination of electron-hole pairs.Recently,using metal-complex to sensitize TiO₂ has attracted much attention.In this paper,we prepared a novel composite photocatalyst by using Fe³⁺-complex（Fe（III）-8-hydroxyquinoline-5-carboxylic acid（HQC））to sensitize TiO₂.Its photocatalytic activity under visible light has been studied.The main research contents are as follows:（1）Fe-HQC complex was prepared by Fe（NO₃）3·9H₂O and8-hydroxyquinoline-5-carboxylic acid under stirring.UV-Vis absorption spectroscopy was used to characterize this complex.（2）A novel composite photocatalyst（Fe（Ⅲ）-HQC）/TiO₂ was obtained via hydrothermal process.The property of（Fe（Ⅲ）-HQC）/TiO₂ was characterized by SEM、TEM、UV-Vis-DRS、XRD and XPS analysis.（3）The photocatalytic performance of（Fe（Ⅲ）-HQC）/TiO₂ to decompose phenol under visible light was investigated.The light source is 300 W xenon lamp.The effects of synthesis condition of（Fe（Ⅲ）-HQC）/TiO₂,such as doping amount of Fe-complex,temperature and time of hydrothermal synthesis,had been discussed.Meanwhile,the recycle,kinetics and photoelectrochemical properties of（Fe（Ⅲ）-HQC）/TiO₂ during the degradation of phenol were studied.The possible catalytic degradation mechanism was proposed according to free radical trapping experiment.（4）The photocatalytic performance of（Fe（Ⅲ）-HQC）/TiO₂ to decompose K₂Cr₂O₇ under visible light was investigated.The light source is 300 W xenon lamp.The effects of the concentration of K₂Cr₂O₇ solution and the amount of（Fe（Ⅲ）-HQC）/TiO₂ had been studied.The recycle,kinetics and photoelectrochemical properties of（Fe（Ⅲ）-HQC）/TiO₂ during the degradation of K₂Cr₂O₇ were discussed.The possible catalytic degradation mechanism was proposed according to free radical trapping experiment.（5）The Simultaneous degradation of phenol and K₂Cr₂O₇ by（Fe（Ⅲ）-HQC）/TiO₂ wasstudied.The best condition of synergetic degradation and possible mechanism were analyzed.