Vis-NIR Light-Responsive Photocatalytic Activity of C3N4-Ag-Ag2O Heterojunction-Decorated Carbon-fiber Cloth as Efficient Filter-Membrane-Shaped Photocatalyst

摘要

C3N4-decorated carbon-fiber (CF) cloth has been demonstrated to be a filter-membrane-shaped photocatalyst for degrading flowing wastewater, but it can be excited only by visible light (lambda450 nm). To extend the photoresponse range to NIR region, herein we have designed and prepared C3N4-Ag-Ag2O heterojunctions on CF cloth. The growth of C3N4 nanosheets (thickness: 20-30 nm) on CF cloth is realized by a thermal condensation method, and then Ag/Ag2O nanoparticles (10-20 nm) are deposited on CF/C3N4 cloth by a chemical precipitation method. CF/C3N4/Ag/Ag2O cloth exhibits excellent flexibility and strong photoabsorption in a broad Vis-NIR region (400-1400 nm), wider than CF/C3N4 (absorption edge: 450 nm). Under the irradiation of 808 nm or 980 nm laser, CF/C3N4/Ag/Ag2O cloth can remove 83 %/41 % AO7 and 72 %/38 % 4-CP in 140 min respectively, significantly higher than those (33 %/13 % AO7 and 31 %/10 % 4-CP) by CF/Ag/Ag2O cloth and those (3 %/1 % AO7 and 0 %/1 % 4-CP) by CF/C3N4 cloth. Interestingly, when CF/C3N4/Ag/Ag2O cloth is used as the filter-membrane to photo-degrade the flowing wastewater (AO7, 20 mg L-1, rate: 1.5 L h(-1)), the removal efficiency of AO7 reaches up 97 % after 8 grade reactors. Therefore, CF/C3N4/Ag/Ag2O cloth can be used as an efficient filter-membrane-shaped photocatalyst with NIR photoresponse.