Preparation And Properties Of TiO₂ Photocatalytic Materials With Graphene Load

Photocatalyst has strong oxidative under the sunshine condition,which can degrade pollutants.Photocatalyst can use the energy of light to completely degrade organic contaminants into CO₂ and H₂O.Therefore,photocatalytic reaction is safe,efficient,environmentally friendly,and with no secondary pollution.TiO₂,Cd S,SnO₂,ZrO₂ are common semiconductor photocatalytic materials,and so are silver salts and porphyrin.Among them,TiO₂ has the advantages of non-toxic,high efficiency,cheap,light corrosion resistance,and high catalytic activity,so it has the best comprehensive performance and the most widely used.TiO₂ is a simple inorganic compound that exists in four basic crystalline forms:anatase,rutile,brookite,and TiO₂（B）.TiO₂（B）is found in very small quantities in nature,the first time that the metastable TiO₂（B）was synthesized by Marchand in the 1980s.TiO₂（B）is a kind of monoclinic phase with metastable structures,low density,asymmetry of crystal structure,a lot of holes and defects exist in internal and surface,which makes it has the low quantum yield and the photogenerated electron-hole pairs recombine rapidly.Compared with titanium alkoxide as the precursor of Ti to synthesize TiO₂ photocatalyst,TiO₂（B）nanoparticles are stable under normal temperature and pressure,easy to conserve,not react with water or organic solvents,which is very suitable as a precursor for the preparation of anatase TiO₂.The main content of this paper is to synthesize flower-like TiO₂（B）/reduced graphene oxide（RGO）nanoparticles.Then synthesize anatase TiO₂/RGO using flower-like TiO₂（B）/RGO nanoparticles as the as precursor.Since the flower-like TiO₂（B）/RGO nanoparticles is assembled by lamellar structure,the thickness of the lamellar layer is about 1 nm,the doping of element I can be realized at low temperature by using its small size effect.Finally,the anatase TiO₂/RGO nanoparticles doped with I is prepared.The main contents and research results of this paper are as follows:（1）Using TiCl₃ as the titanium source and ethylene glycol as the solvent,TiO₂（B）nanomaterials loaded with RGO were prepared by solvothermal method.The morphology and chemical composition of the composite were characterized by XRD,TEM,Raman,XPS and BET analysis.The photocatalytic activity of the composite was studied by testing degradation rate of methylene blue（MB）under ultraviolet light.The TEM results showed that the petal-like structure was successfully loaded onto the graphene lamellar structure.The BET analysis showed that the specific surface area of the composite was greatly increased with RGO loading.From the photocatalytic experiments,the best RGO loading amount is 5%,and the photocatalytic performance will be reduced if the amount is less or greater than 5%.（2）The prepared TiO₂（B）loaded with graphene was used as the precursor and then calcined at a certain temperature to obtain anatase crystal TiO₂ composite material loaded with reduced graphene oxide.The morphology and chemical composition of the composite were characterized by XRD,TEM,Raman,XPS and BET analysis.The photocatalytic activity of the composite was studied by testing degradation rate of MB under ultraviolet light.The TEM results show that the nanostructure of the composite remains flower-like morphology after high temperature annealing.XRD shows that the crystal of the composite changes from monoclinic phase to anatase phase.In comparison test with the commercial P25photocatalytic performance,the ability of anatase TiO₂/RGO to degrade MB is increased by 21%.（3）The prepared TiO₂（B）loaded with graphene was used as the precursor,due to the petal-like structure assembled by nanosheets and the thickness of nanosheets is about 1 nm.element I can be doped at low temperature by its small size effect.In order to further improve its photocatalytic ability,firstly,the TiO₂（B）loaded with reduced graphene oxide was synthesized and next doping iodine element.The morphology and chemical composition of the composite were characterized by XRD,TEM,Raman,XPS and BET analysis.The photocatalytic activity of the composite was studied by testing degradation rate of MB under ultraviolet light.The XPS analysis proves the doping of element I.The results of photocatalytic performance test showed that the graphene loading and I-doping increased the photocatalytic degradation rate.