Vis‐NIR Light‐Responsive Photocatalytic Activity of C 3 N 4 −Ag−Ag 2 O Heterojunction‐Decorated Carbon‐fiber Cloth as Efficient Filter‐Membrane‐Shaped Photocatalyst

C 3 N 4 ‐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 (λ<450 nm). To extend the photoresponse range to NIR region, herein we have designed and prepared C 3 N 4 −Ag−Ag 2 O heterojunctions on CF cloth. The growth of C 3 N 4 nanosheets (thickness: 20–30 nm) on CF cloth is realized by a thermal condensation method, and then Ag/Ag 2 O nanoparticles (10–20 nm) are deposited on CF/C 3 N 4 cloth by a chemical precipitation method. CF/C 3 N 4 /Ag/Ag 2 O cloth exhibits excellent flexibility and strong photoabsorption in a broad Vis‐NIR region (400–1400 nm), wider than CF/C 3 N 4 (absorption edge: 450 nm). Under the irradiation of 808 nm or 980 nm laser, CF/C 3 N 4 /Ag/Ag 2 O 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/Ag 2 O cloth and those (3 %/1 % AO7 and 0 %/1 % 4‐CP) by CF/C 3 N 4 cloth. Interestingly, when CF/C 3 N 4 /Ag/Ag 2 O 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/C 3 N 4 /Ag/Ag 2 O cloth can be used as an efficient filter‐membrane‐shaped photocatalyst with NIR photoresponse.