Electron Beam Irradiation Modification Of Indium/Bismuth Based Semiconductor And Its Photocatalytic REDOX Mechanism

With the increasing public awareness of environmental protection and the concern for clean energy,semiconductor materials are increasingly widely used in the field of environmental governance.Among them,In/Bi semiconductors have been extensively studied because of their excellent physical and chemical properties.Nevertheless,In/Bi semiconductors still have high photo-generated carrier recombination rate and serious photo-corrosion.In this paper,the In/Bi based semiconductor materials were modified by electron beam irradiation,and the photocatalytic oxidation-reduction properties of the modified materials were studied.The specific contents are as follows:（1）The photocatalytic oxidation performance of In₂S₃-CdIn₂S₄@X（X=Ag/Ag3PO4/AgI）ternary heterostructure nanotubes was modified by electron beam irradiation was explored.And under visible light,In₂S₃-CdIn₂S₄@X（X=Ag/Ag3PO4/AgI）was applied to the degradation of carmine and Cr6+.The results showed that In₂S₃-CdIn₂S₄,In₂S₃-CdIn₂S₄@AgI before EBI and In₂S₃-CdIn₂S₄@AgI after electron beam irradiation can completely remove carmine and Cr6+in 80,20 and 5 min,respectively.Photoluminescence（PL）spectrum results show that electron beam irradiation can significantly reduce the electron-hole recombination rate in In₂S₃-CdIn₂S₄@AgI.The electrochemical impedance spectroscopy（EIS）results further confirm that In₂S₃-CdIn₂S₄@AgI irradiated by electron beam has a high efficiency of electron-hole separation.These results indicate that electron beam irradiation can enhance the photocatalytic activity of In₂S₃-CdIn₂S₄@AgI ternary heterostructure nanotubes.Electron paramagnetic resonance（EPR）experiments have further confirmed that the main active groups in In₂S₃-CdIn₂S₄@AgI photocatalytic system are ·O2-and h+.（2）The photocatalytic performance of Bi₆O₇FC₁₃ nanotubes modified by electron beam irradiation was explored.First,Bi₆O₇FC₁₃ nanotubes were synthesized by hydrothermal reaction,and the reverse growth of Bi quantum dots at the interface of Bi@Bi₆O₇FC₁₃-X（X=20/60/90）nanotubes was realized by the controllable adjustment of electron beam irradiation.Subsequently,Bi@Bi₆O₇FC₁₃-X（X=20/60/90）was applied to the photocatalytic reduction of CO₂.The results showed that after 4 h of photocatalytic reduction,the rate of CO formation by Bi@Bi₆O₇FC₁₃-90 was 15.79 μmol·g-1·h-1,which is 6.29 times that of Bi₆O₇FCl₃.The PL results showed that the PL peaks of Bi@Bi₆O₇FC₁₃-90 were the lowest after electron beam irradiation,indicating that the Bi quantum dots reduced by electron beam irradiation inhibited the recombination of electron-hole pairs in Bi₆O₇FC₁₃ nanotubes.The synergistic effect of the dots makes the electrons and holes separate quickly,thereby increasing the lifespan of the photogenerated electrons.The EPR experiment confirmed that the h⁺,·O₂^-and ·OH generated on the surface of the photocatalyst after light excitation improved the efficiency of photocatalytic reduction of CO₂.（3）To investigate the photocatalytic performance of lamellar Bi₂WO₆ microspheres modified by electron beam irradiation.Bix@Bi_2-x WOn with oxygen defect was obtained by electron beam irradiation of Bi-O bond in Bi₂WO₆ as a template.The obtained photocatalyst was applied to the photocatalytic degradation of oxytetracycline.The results showed that Bi₂WO₆ could achieve equilibrium degradation of oxytetracycline within 50 min,and Bi_0.32@Bi_1.68WO_5.80 could completely remove oxytetracycline in water within 20 min.XPS results show that compared with Bi₂WO₆,the positive polarizability of Bi and W in Bi_0.32@Bi_1.68WO_5.80 increases,while the negative polarizability of O increases,which proves the existence of Bi0 and oxygen defects.The DFT results further confirmed that the electron cloud density at the oxygen defect site increased,which promoted the photocatalytic reaction.The results of EPR experiments show that the lattice oxygen defects generated by electron beam irradiation can enhance the generation of ·OH radicals,which can activate SO₄^2-to generate ·SO₄^-radicals.