| The problem of industrial pollution has attracted wide attention of governments and people with steady and fast development of industrialization in modern society.In order to solve this prominent contradiction,various methods are used to degrade industrial pollutants.Photocatalytic technology is considered to be the most industrialized and feasible way,because of its advantages of low energy consumption and high efficiency.Because of its many advantages,such as cheap,stable physicochemical properties and no secondary pollution,Ti O2 is considered to be the most promising semiconductor material.However,Ti O2 has many defects,such as larger band gap,which only responds to ultraviolet light(3%-5%)and low quantum mobility leads to high recombination rate of photoproduction electron-hole pair.Therefore,it is a significant problem to prepare Ti O2 photocatalyst that can inhibit photoelectron-hole pair and have narrow band gap.At present,according to these defects,Ti O2 can be modified to improve their photocatalytic properties through doping of non-metallic elements,heterostructure,surface modification and precious metal modification.In 2004,the new type of material graphene was born,this single-atomic and twodimensional honeycomb-like carbon nanomaterials with excellent properties have become a new favorite in material world.Graphene not only has excellent electrical conductivity,but also has huge specific surface area and excellent adsorption capacity.It is considered to be the most potential carrier.Therefore,introducing graphene into Ti O2 has great significance.There have been some literature about introduction of graphene to Ti O2 to improve its photocatalytic efficiency,but its photocatalytic efficiency is far from satisfactory.Therefore,it is still worth studying.The preparation methods and photocatalytic properties of Ti O2/graphene composites were studied in this paper.In this experiment,Ti O2/graphene nanocomposites were prepared by electrospinning and hydrothermal method,which mainly solved problems of specific surface area,response range of solar light,high recombination rate of electron-hole pair and photocatalytic performance of samples was tested.The research contents of this paper are divided into two parts:(1)Uniform diameter Ti O2 nanotube was prepared by electrospinning and oil/water phase separation technology.The doping optimization of Ti O2 nanotube/graphene composite with different mass ratio was prepared by simple green hydrothermal method.The morphology,specific surface area,state of constituent elements,light response range and forbidden bandwidth were investigated by XRD,Raman,TEM,SEM,BET,XPS,UV-Vis and other modern detection techniques.The influence of photocatalytic efficiency and catalytic mechanism of samples is analyzed.The results show that all samples have obvious tubular structure.The introduction of graphene significantly increased specific surface area of Ti O2/graphene composites,which is beneficial to contact and adsorption of pollutants.The formation of chemical bonds between Ti O2 and graphene is beneficial to stability and reduced band gap,which is beneficial to the use of light and to improve photocatalytic efficiency.Usually Ti O2 nanotubes doped with 10% graphene exhibited the best photocatalytic efficiency.(2)Ti O2 combine with graphene can overcome many shortcomings,enhance utilization of sun light and significantly improve photocatalytic efficiency.However,improving photocatalytic efficiency of Ti O2 is limited.Therefore,multiphase composite has become a new trend and hotspot in the future.Silver contacts with Ti O2 will form Schottky barrier,which helps to reduce recombination rate of photoelectronhole pairs.The unique plasma effect can promote capture ability of Ti O2 and enhance utilization of light.Therefore,we introduce graphene and silver to Ti O2 to study the photocatalytic efficiency and photocatalytic mechanism.It provides experimental samples and theoretical basis for further improving photocatalytic efficiency. |
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