Abstract
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•GO–Ag3PO4 is prepared by electrostatically-driven assembly of Ag+ on GO surface.•GO–Ag3PO4 exhibits enhanced photocatalytic activity for bacteria inactivation.•The photocatalyst shows more efficiency on S. aureus than E. coli.•The h+ plays more important role in photocatalytic disinfection process than OH.•Existence of GO reduces the recombination of photogenerated electron–hole pairs.
A visible light-responsive graphene oxide–Ag3PO4 (GO–Ag3PO4) was prepared using a facile electrostatically driven self-assembly method. Ag3PO4 particles were uniformly deposited on the surface of graphene oxide (GO) sheets. The GO–Ag3PO4 composite was more active in photocatalytically killing both Gram-positive and Gram-negative bacteria compared with pure Ag3PO4. The significantly enhanced photocatalytic and bactericidal performance of GO–Ag3PO4 composite could be attributed to (i) the more active adsorption sites on the GO surface for bacteria, and (ii) the reduced recombination of photogenerated electron–hole pairs relying on the excellent electronic conductivity and store electricity of GO. According to the results, most of Escherichia coli (E. coli) bacteria were killed within 30min under visible light irradiation, while Staphylococcus aureus (S. aureus) bacteria were almost completely killed within only 25min. The difference could be due to the outer membrane of E. coli, which made them more resistant to the cell membrane damage caused by GO–Ag3PO4 than S. aureus lack of the outer membrane. In addition, the radical capture experiments confirmed the involvement of active holes and reactive oxygen species (ROS) in the antibacterial process of GO–Ag3PO4. All the results demonstrated that the synthesized GO–Ag3PO4 composite, as a visible light-responsive antibacterial material, has a great promising for water disinfection.