Assembly And Photocatalytic Properties Of Mesoporous Spherical Shell Based Composites

PS fine powder consisting of microspheres was prepared by dispersion polymerization.Then,sulfonated polystyrene(PS)microspheres have been used as template to produce mesoporous spherical shells of MOFs of Fe-MIL-88B-NH2 and polyaniline(M-PANI).Mesoporous Fe-MIL-88B-NH2@AgI,M-PANI@AgI and M-PANI/Ag@AgCl were prepared by using mesoporous spherical shells of Fe-MIL-88B-NH2 and PANI as matrix.A series of characterizations were carried out on the materials,and their photocatalytic performance under visible light and synergistic mechanism were studied.Come to the following conclusions:(1)In this dissertation,the mesoporous spherical AgI@Fe-MIL-88B-NH2 photocatalysts was prepared by in situ compositing.The photocatalytic activities of the catalysts were evaluated by measuring the degradation of Rhodamine B(RhB)under visible light.Meanwhile,the field emission scanning electron microscope(FESEM),X-ray diffractometry(XRD),fourier transform infrared(FT-IR),X-ray photo-electron spectroscopy(XPS)measurements were used to analyse the mesoporous AgI @Fe-MIL-88B-NH2.It was found that the photocatalytic properties of the composites were higher than those of the pure materials,and this is due to the formation of "Z-Scheme" heterojunction between mesoporous Fe-MIL-88B-NH2 and AgI which can not only enhance the separation efficiency of photogenerated electron and hole pairs but also improve the oxidation-reduction ability of the electron and hole.(2)A novel visible-light-active AgI modified AgI@M-PANI composite was prepared by chemisorption method.The degradation of colorless phenol and colored RhB dye under visible light irradiation was used to evaluate the activity of the catalyst and it can be concluded that AgI@7%M-PANI has the best photocatalytic effect,which is 18 times and 9 times of pure M-PANI and AgI.The improved photocatalytic performance is due to synergistic effects derived from the AgI modified mesoporous PANI spherical shell with open pore,which can effectively accelerate the charge separation,and reinforce the photostability of the composite.(3)Ag@AgCl synthesized via a modified coprecipitation method and the photocatalysts of Ag@AgCl/M-PANI were prepared by chemisorption method.Their performances on the photocatalytic degradation of RhB and phenol were explored under visible light.The experimental results showed that Ag@AgCl/6%M-PANI hybrids exhibited a superior degradation efficiency both for RhB and phenol than M-PANI and Ag@AgCl.The enhanced catalytic activity is mainly due to the phenomenon of surface plasmonic resonance(SPR)of noble metal which can enhance charge separation and transportation between the AgCl and M-PANI nanostructures.The charge-transfer mechanism was supported by the photoluminescence photoelectro chemical results.