Preparation And Photocatalytic Properties Of TiO₂-based Composites

As a traditional semiconductor photocatalyst,Titanium dioxide?TiO₂?,with the high photocatalytic activity,good physical and chemical stability and low price,is widely used in the fields of photocatalytic hydrogen production and sewage treatment,and always deemed as the research hotspot.However,as a wide band semiconductor,with the lower photon utilization,the carriers are easily to compound,which severely limits its application in the field of photocatalysis.Though many researches have been reported for improving the photocatalytic performance,there still leaves lots of challenge.Based on previous researches,this paper aims to modified the intrinsic property of TiO₂.Firstly,TiO₂ nanotubes with porous surface were prepared for improving the specific surface area,which is benefit to the improvement of catalytic performance,and then prepared the TiO₂/Ag₃PO₄,TiO₂/MoS₂/Ag₃PO₄/Ag heterojunction by introducing the Ag₃PO₄,MoS₂,Ag₃PO₄/Ag for improving the efficiency of light energy utilization and separation efficiency of carrier.The main research contents and results are as follows:?1?The porous TiO₂ nanotubes with large specific surface area were prepared by electrostatic spinning method via adding pump oil into the precursor fluid.And the optimal conditions were explorered by regulating the dosage of oil and the annealing temperature.Results show that the tube wall depends on the dosage of oil and the crystal structure depends on the annealing temperature.Further,the porous and hollow structure and the microstructure of the sample could characterized by SEM,TEM and XRD,and the catalytic performance of porous TiO₂ nanotubes could be tested by dissolving MB under ultraviolet lamp illuminate,which is superior to that of nanofiber.?2?The porous TiO₂ nanotubes were chosen as the substrate,then the TiO₂/Ag₃PO₄heterogeneity was prepared by chemical deposition,and the influence of Ag₃PO₄ content on catalytic performance are studied.The results of SEM,XRD,TEM and XPS imply that the Ag₃PO₄nanoparticles have been introduced on to the surface of TiO₂ nanotubes successfully.Compared with the unmodified samples,the photocatalytic activity of the as-prepared porous TiO₂nanotubes/Ag₃PO₄ heterojunction exhibit a remarkable enhancement by the degradation of methylene blue?MB?under the sunlight.Further,the Z-Scheme structure of the samples and the porous-tubular structure of the TiO₂ are considered as the main reasons for the enhancement.?3?The porous TiO₂ nanotubes were chosen as the substrate,then the TiO₂/MoS₂heterostructure was prepared via hydrothermal method,and the TiO₂/MoS₂/Ag₃PO₄/Ag heterogeneity was prepared by ion exchange method.The results of SEM,XRD,TEM and XPS imply that the Ag₃PO₄ nanoparticles have deposited on the surfaces of Mo S₂ nanosheets and the nanosheets are separated on the TiO₂ nanotubes successfully.Compared with the unmodified samples,the photocatalytic activity of the as-prepared TiO₂/MoS₂/Ag₃PO₄/Ag nano-heterojunction exhibits a remarkable enhancement by the degradation of methylene blue?MB?under the sunlight.Further,the quaternary Z-scheme heterojunction,the tubular structure of the TiO₂ and lamellar structure of the MoS₂ are considered as the main reasons for the enhancement.