Titanium-based Material(Bismuth Titanate/Titanium Dioxide) Composite Catalyst System Construction And Its Photocatalytic Performance

In recent years,photocatalytic technology has been considered as an effective way to solve the increasingly serious problems of energy shortage and environmental pollution,among which,the exploration and development of efficient and durable visible light responsive photocatalyst is a research hotspot.In this paper,two kinds of composite catalyst systems,g-C₃N₄/Bi₄Ti₃O₁₂and Cu/TiO₂,were prepared by using electrospinning technology,mixed calcination technology and light reduction technology.The photocatalytic activity of the catalyst was studied by a comprehensive characterization test.The detailed research contents are as follows:1.A series of novel g-C₃N₄/Bi₄Ti₃O₁₂（CN/BTO-X）hollow nanofiber composites were prepared by simple electrospinning/calcination combined with thermal polymerization.SEM and TEM images show that the CN-BTO composite is mainly composed of hollow nanofibers with a diameter of 110±20 nm.XPS results confirmed the interfacial interaction between BTO and CN,indicating the formation of heterojunctions between these components.Photocatalytic performance tests showed that the synthesized CN/BTO composites were prepared in visible light（λ>420 nm）has excellent and stable photocatalytic performance,and can degrade a variety of pollutants,including Rh B,MO,TC and Cr（VI）).CN/BTO-9 showed the best photocatalytic performance with rate constants of 0.03064 min^-1（TC）,0.11274 min^-1（Rh B）,0.04474 min^-1（MO）and 0.01938min^-1（Cr（VI））,respectively.Its excellent catalytic performance is attributed to its high specific surface area,enhanced visible light absorption,highly oxidizing heterostructures and efficient separation of photogenerated carriers,as well as its unique hollow nanofiber structure.Active species trapping test and ESR measurement confirmed that h⁺and·O₂^-were the main active species for degrading Rh B and TC.The photocatalytic mechanism of the composite catalyst system was discussed by band gap structure,DFT computation and free radical trapping experiment.2.Ti O₂nanofibers were prepared by electrospinning/high temperature calcination technology.Then,non-noble metal Cu nanoparticles were loaded on Ti O₂by light reduction method to construct the Cu/Ti O₂composite photocatalyst system.The results show that the SPR effect of Cu nanoparticles significantly enhances the visible light absorption range of Cu/Ti O₂.Cu nanoparticles SPR can generate local electromagnetic fields,which can significantly improve the separation efficiency of photogenerated carriers in the composites.A series of research results show that the Cu/Ti O₂composite has excellent and reliable activity of decompose aquatic hydrogen and degradation of Rh B,Tc and Cr（VI）by visible light（λ>420 nm）.Among the prepared composite materials,1%Cu/Ti O₂sample has the best photocatalytic activity,and its hydrogen production rate is1416μmol g^-1h^-1,which is 59 times that of pure Ti O₂.The degradation rate constants were0.12522 min^-1（TC）,0.02991 min^-1（Rh B）and 0.02519 min^-1（Cr（VI））respectively.Based on the results of PL,i-t,EIS,ESR and free radical capture experiment,the photocatalytic reaction mechanism of the catalyst system was proposed.By constructing two kinds of composite photocatalyst systems,the visible light absorption range of Ti-based materials was effectively extended,and the separation efficiency of photogenerated carriers was improved,thus improving the photocatalytic activity.This research topic not only enriches our knowledge of designing and fabricating novel composite catalyst systems,but also provides a promising idea for solving the problems of environmental pollution and energy shortage in the future.