Study On Structure Control And Photocatalytic Properties Of TiO₂ Based Composite

Solar energy is one of the most important clean energy on the earth.It is closely related to human life.It is very important for human survival and development to develop solar energy efficiently and sustainably.Semiconductor photocatalyst technology is a new technology which uses mild photochemical reaction to store and utilize solar energy.It is the goal of many researchers to transform solar energy efficiently through semiconductor photocatalytic technology to develop new energy and repair the environment.In this paper,aiming at the inherent defects of TiO₂ semiconductors,various strategies are adopted to modify TiO₂ photocatalytic materials.The relationship between the composition,structure and properties of TiO₂ photocatalysis materials was explored in detail.The main research contents and conclusions of this paper are as follows:?1?TiO₂/g-C₃N₄ heterojunction composites were prepared by simple stirring and calcination with titanium isopropoxide and melamine as precursors.Then,a series of TiO₂/g-C₃N₄/Ag?TCA?composites were prepared by wet chemical reduction method.XRD,TEM,HRTEM,EDS,XPS,bet,Raman,PL and UV-vis diffuse reflectance spectra were used to study TCA composites in detail.The results show that TCA composites exhibit improved efficiency of photocarriers separation and enhanced utilization of visible light,which is the result of the synergistic effect of the three materials.Under the simulated sunlight,TCA composites with 1%Ag had the best photodegradation performance for RhB,and its degradation rate was 91.4%at 60 min.After several cycles of tests,TCA composites maintained excellent degradation performance,which showed that TCA composites had good photochemical stability.In addition,the possible mechanism of photodegradation of TCA composites was proposed based on the experimental results.?2?Hollow TiO₂@g-C₃N₄/Co₃O₄ core-shell microspheres were prepared by a multi-step synthesis method with template participation.The results show that the hollow structure of the heterogeneous shell can separate the photogenerated carriers,and the photogenerated holes transferred to the surface will be further captured by Co₃O₄ nanoparticles to obtain the exposed oxide surface.This new type of hollow microspheres can realize the effective transfer and extended absorption of photocarriers at the same time.The optimized TiO₂@g-C₃N₄/Co₃O₄ nanospheres have good photodegradation activity to tetracycline?TC?and methyl orange?MO?due to these structural and compositional characteristics.Under simulated sunlight,the degradation rates of TC?10 mg/L?and Mo?25 mg/L?were 91.6%and97.8%respectively at 60 min.At the same time,after several test cycles,the composite photocatalyst still has high activity.According to the experimental results,we also propose the possible transmission path of the photocarriers.?3?The TiO₂@CuS double-shell nanoboxes were prepared by a multi-step synthesis method with template participation and used for photocatalytic degradation of tetracycline.We found that the thickness of the TiO₂ shell will directly affect the activity of the TiO₂@CuS double-shell nanoboxes.Under simulated sunlight,the optimized TiO₂@CuS double-shell nanoboxes exhibited excellent TC degradation efficiency?at 60 min,the degradation efficiency was 96.5%?and maintained good stability in multiple cycles.The improvement in the activity of the composite photocatalyst can be attributed to a variety of factors,including good visible light capture capability,improved photo-generated carrier separation,and effective suppression of photocorrosion.In addition,the unique cavity structure not only promotes carrier migration,but also improves light efficiency.This work provides a new perspective for the design of hollow structures that effectively degrade antibiotics and protect the sulfide core.