Preparation Of Ternary TiO₂-Au-BiOX（X=Br,I） Heterojunction Photocatalyst And Study On Photocatalytic Performance

Photocatalysis technique is a feasible strategy to solve this problem due to its green and pollution-free.Among the many known photocatalytic semiconductors,wide band gap TiO₂（3.2eV）has been widely studied due to its non-toxicity,low cost,and environmental protection.But a single TiO₂ can only be excited by ultraviolet light,so its further application is limited.To solve this problem,in this work:（1）TiO₂-Au-BiOBr ternary photocatalyst was constructed by adjusting the content of Au nanoparticles and BiOBr supported on TiO₂ NFs.Compared with other single-component or two-component photocatalysts,TiO₂-Au-BiOBr NFs exhibit excellent photocatalytic performance and good stability for the degradation of Rhodamine B（RhB）under full-wavelength irradiation.The reaction mechanism of the TiO₂-Au-BiOBr Z-scheme system was studied through XPS,photoelectrochemical test and free radical capture experiment.In addition,the photocatalyst also has excellent photocatalytic activity and can degrade methyl orange and methylene blue.（2）Using BiOl with visible light response instead of BiOBr,a TiO₂-Au-BiOI ternary photocatalyst was constructed to enhance the photocatalytic nitrogen fixation in pure water.Photocatalytic nitrogen fixation experiments show that the nitrogen fixation performance of TiO₂-Au-BiOI is higher than that of TiO₂-Au-BiOBr.And through UV-Vis,PL and transient photocurrent response to study the root cause of its photocatalytic enhancement.（3）The construction of TiO₂-BiOI-Au and TiO₂-BiOI proves that TiO₂-Au-BiOI has a"Z-scheme" electron transport path.Photocatalytic nitrogen fixation experiments show that TiO₂-Au-BiOI can significantly improve its N2 fixation ability in pure water system to 543.53μmolL^-1 h^-1 g^-1.It is 1.68 times higher than TiO₂-BiOI-Au nanocomposite.Combined with the material structure and morphology characterization,XPS,UV-Vis,PL,photoelectrochemical testing,EPR,FDTD simulation,etc.,the Z-scheme heterojunction photocatalysis mechanism of the modified TiO₂-Au-BiOI was further verified.In this thesis,by adjusting the structure and composition of the material,a Z-scheme heterojunction is constructed to enhance its photocatalytic performance,which has reference value for the design of a ternary heterojunction photocatalyst.