Plasmonic Ag decorated graphitic carbon nitride sheets with enhanced visible-light response for photocatalytic water disinfection and organic pollutant removal

Photocatalytic disinfection with high performance is thought to be a promising way for water purification . Herein, plasmonic Ag doped urea-derived graphitic carbon nitride (g-C 3 N 4 ) composites were fabricated via in-situ photo-deposition at room temperature as the visible-light photocatalyst. Scan electron microscopy and transmission electron microscopy images showed the uniform dispersion of Ag nanoparticles on the surface of g-C 3 N 4 sheet, which facilitated the synergistic effect of antibacterial performance from Ag and photocatalytic property from Ag/g-C 3 N 4 composites. Photocatalytic water disinfection against Escherichia coli with visible light was performed to demonstrate the improved photocatalytic property with assistance of Ag. The 3-Ag/g-C 3 N 4 exhibited the best bactericidal performance by inactivating all bacteria within 120 min with damaged cell membranes of Escherichia coli observed by scan electron microscopy and transmission electron microscopy images. Photoluminescence spectra, steady-state surface photovoltage spectra, photocurrent response, and electrochemical impedance spectra results revealed that Ag nanoparticles inhibited the recombination of photo-generated e − and h + pairs and further reinforced the photocatalytic performance of g-C 3 N 4 . Scavenger experiments indicated that h + produced on valence band of g-C 3 N 4 dominated the photocatalytic disinfection process against Escherichia coli . This work further proved Ag/g-C 3 N 4 showed great potential in photocatalytic water disinfection under visible-light irradiation.