Study On The Preparation,characterzation And Photocatalytic Performance Of Narrowband CoTiO₃ And Its Composites

Environmental pollution has become an urgent need to address the era of the key issues to deal with,photocatalytic degradation of pollutants has gradually developed to solve environmental and energy issues,an important technology to solve environmental pollution,especially water pollution is an important means of photocatalytic technology The focus of the development of high activity,high stability,low cost and non-toxic characteristics of the photocatalyst.CoTiO₃ is an ABO₃-type perovskite oxide with a suitable bandgap?².25 eV?,which has a strong absorption of visible light and a large absorption coefficient.After absorption of light energy,CoTiO₃ can generate an electronic transition to form an electron-hole pairs,and CoTiO₃ carrier mobility,high stability,so CoTiO₃ is a potential photocatalytic material.At present,the preparation methods of a single CoTiO₃material such as polyol method,sol-gel method,stearic acid gel method,coprecipitation method,pulsed laser precipitation method and solid state method and the like,the size and morphology of CoTiO₃ particles prepared by these methods are not Controlled,which limits its application in high technology.In this dissertation,CoTiO₃ was taken as the research object.Several kinds of CoTiO₃-based composites were prepared from the relationship between the structure and properties of materials.CoTiO₃ was compounded with several other semiconductors to form double charge transfer Quality knot,greatly reducing the photo-generated electron-hole recombination probability,thereby enhancing the photocatalytic efficiency.In this thesis,the process,basic principle and research status of semiconductor photocatalysis are briefly introduced.The structure,properties and preparation methods of CoTiO₃ are introduced emphatically.The specific research work of the dissertation is as follows:1.The CoTiO₃ narrow band-based materials were obtained by one-step calcination using cobalt acetate and butyl titanate as raw materials by sol-gel method.XRD,XRD,The structure,phase,morphology,composition and optical properties of the obtained samples were characterized by means of transmission electron microscopy?TEM?,x-ray photoelectron spectroscopy?XPS?and UV-vis DRS.Rhodamine B?RhB?aqueous solution was used as the simulated wastewater and the visible light of 30W was used as light source to evaluate the photocatalytic degradation performance of the material.The results show that the CoTiO₃ narrow band base material has a good response to visible light.2.The CoTiO₃/MFe₂O₄ composite materials were prepared by hydrothermally dispersing the CoTiO₃ in a ferrite material to obtain a CoTiO₃/MFe₂O₄?Zn,Ni,Mg?heterojunction materials.XRD,TEM,EDS,XPS,UV-vis DRS and other means were used to analyze the structure,phase,morphology,composition and optical properties of the sample were characterized;studied the resulting material photocatalytic degradation.The results show that the composite photocatalytic efficiency has been enhanced.Through the study on the mechanism of photocatalytic degradation,we found that heterogeneous junction materials of CoTiO₃/MFe₂O₄?Zn,Ni,Mg?form a heterogeneous Z system with stronger oxidation and reduction ability,which is conducive to the separation of photogenerated electron-hole,Thus enhancing the photocatalytic degradation of the heterojunction.And we found that the CoTiO₃/MFe₂O₄?Zn,Ni,Mg?heterojunction materials have better UV-vis absorption properties in the 3:1 samples.3.The M₂S₃?In,Gd,Ce,Nd,Pr?materials were prepared by hydrothermal method using indium chloride and thioacetamide as raw materials.The prepared CoTiO₃ was ultrasonically dispersed in the prepared M₂S₃?In,Gd,Ce,Nd,Pr?The structure,phase and morphology of CoTiO₃/M₂S₃?M=In,Gd,Ce,Nd,Pr?heterostructures were prepared by hydrothermal method.The samples were characterized by XRD,TEM,EDS,XPS and UV-vis DRS.Composition and optical properties were analyzed and characterized;the photocatalytic degradation properties of the resulting materials were studied.The results show that the composite photocatalytic efficiency has been enhanced.The research work of this dissertation provides meaningful data for the further development of g-C-based photocatalytic materials.