Fabrication of a three-dimensional porous Z-scheme silver/silver bromide/graphitic carbon nitride@nitrogen-doped graphene aerogel with enhanced visible-light photocatalytic and antibacterial activities

Abstract

A novel three-dimensional (3D) porous Z-scheme silver/silver bromide/graphitic carbon nitride@nitrogen-doped graphene aerogel (Ag/AgBr/g-C3N4@NGA) photocatalyst was successfully fabricated by a facile hydrothermal and freeze-drying method, and its photocatalytic degradation performance and inactivation effects were also evaluated. The series of characterization results certified that the obtained Ag/AgBr/g-C3N4@NGA synergistically integrates the structural and functional advantages of the Ag/AgBr species and g-C3N4 into the 3D macroscopic porous nitrogen-doped graphene aerogel (NGA) with high conductivity. Benefiting from a unique composition and structure, the obtained Ag/AgBr/g-C3N4@NGA exhibited excellent photocatalytic degradation efficiency for methyl orange (MO), approximately 96% after 30 min of visible-light illumination, which was approximately 1.7 times higher than that of a graphitic carbon nitride@nitrogen-doped graphene aerogel (g-C3N4@NGA). Meanwhile, Ag/AgBr/g-C3N4@NGA possessed high photodegradation efficiency for bisphenol A (BPA), approximately 92% within 120 min. Based on the underlying premise of maintaining the original morphology, the mass loss of Ag/AgBr/g-C3N4@NGA is below 5%, and its excellent photocatalytic performance was also well maintained after eight cycles. Moreover, Ag/AgBr/g-C3N4@NGA has a disinfection effect on E. coli (approximately 6 log inactivation) and S. aureus (approximately 1.2 log inactivation) in 60 min of visible-light illumination, and an excellent disinfection effect on E. coli was maintained after five applications.