| Recently,the use of semiconductor materials has drawn extensive attentions due totheir outstanding advantages in the treatment of environmental pollution.Among these materials,titanium dioxide?Ti O2?shows great potential in the field of photocatalysis,which is attributed to its stable performance,rich raw materials and low cost.However,it can only be excited by UV light because of its wide band gap,which brings great hindrance to its industrial application.Therefore,scholars from various countries have done a lot of research on expanding the spectral response range of Ti O2.One of the simple and effective methods is the recombination of semiconductors.As an organic semiconductor material,conjugated polymer not only has electrochemical activity,but also has a series of optical properties.In the design and synthesis process,the band gap width of the polymer can be modified by changing the substituents in the side chain.Similarly,the positions of HOMO and LUMO levels in conjugated polymer can also be changed.However,D-A CMPs still suffer from some drawbacks such as easy recombination of photogenerated electrons and poor photocatalytic performance,owing to their narrow band gaps.Therefore,in this paper,a new type of D-A CMPs material was designed and synthesized,selecting tramline as electron donor and benzothiadiazole as electron acceptor.Additionally,a series of heterojunction photocatalysts were synthesized by compounding the synthetic polymer with Ti O2 in different proportions.The photocatalytic properties of these heterojunction photocatalysts have been evaluated using Bisphenol A?BPA?as the target pollutant,and the composite photocatalytic material which with the best degradation performance has been screened out.Otherwise,the mechanism of the catalytic degradation of bisphenol A under visible light was discussed.The main results are as follows:1. UV diffuse reflectance spectra show that the band gap of conjugated polymer TPABT is only 2.2e V,which has strong visible light absorption properties,and the experiment of BPA degradation under visible light shows that the polymer can degrade BPA under visible light.However,the degradation efficiency of polymer TPABT is still low.2. Five kinds of TPABT/Ti O2 composite photocatalytic materials with different TPABT content were prepared by in-situ polymerization.Subsequently,the degradation experiments of BPA were carried out.The results show that the photocatalytic performance of the composites first increased and then decreased with the increase of TPABT content in these composite photocatalysts.However,compared with single TPABT and Ti O2,the catalytic ability of these composite photocatalysts have improved in different degrees.When the ratio of TPABT to Ti O2is 10%,the composite catalyst shows the best photocatalytic performance,in which system the BPA degradation rate is 4 times and 8 times higher than that of pure TPABT and Ti O2,respectively.3. Electron paramagnetic resonance?ESR?,electrochemical impedance spectroscopy?EIS?,fluorescence spectroscopy?PL?,transient photocurrent and active species capture experiment were carried out to study the photocatalytic mechanism of TPABT/Ti O2 composites.The trapping experiment of active species showed that·O2-,h+and hydroxyl were the main active species.Otherwise,the photocatalytic degradation mechanism of the reaction system was also speculated. |
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