Graphitic carbon nitride loaded with bismuth nanoparticles displays antibacterial photocatalytic activity

Metal-free graphitic carbon nitride nanomaterials have been widely applied in the medical antibacterial field owing to their high anisotropy, excellent stability, satisfactory biocompatibility, and non-toxicity. Herein, Bi/C3N4 nanocomposites were successfully constructed by hydrothermal method followed by loading bismuth on the surface of graphite carbon nitride. Bi nanospheres were tightly combined with the layered g-C3N4 surface to promote effective separation of photo-induced charges, which results in the Bi/C3N4 composite material that exhibited excellent photocatalytic activity under visible light. In addition, the surface plasmon resonance characteristics of semi-metal Bi further enhanced the visible-light absorption of the Bi/C3N4. However, excessive Bi may inhibit the light-trapping ability of Bi/C3N4. 1.0% Bi/C3N4 demonstrates excellent bactericidal efficiency as high as 96.4% against Escherichia coli (E. coli), which is attributed to the promotion of the production of reactive oxidative species. The enhanced mechanism of Bi/C3N4 synergistically achieving enhanced photocatalytic antibacterial activity under the coupling of multiple advantages was clarified, providing theoretical guidance for its application in the field of water disinfection and antibacterial treatment.

Automated summary

Metal-free graphitic carbon nitride nanomaterials have great potential in the medical antibacterial field due to their excellent properties. The construction of Bi/C3N4 nanocomposites and the effective separation of photo-induced charges contributes to the enhanced photocatalytic antibacterial activity of the material under visible light. The theoretical guidance provided by this study clarifies the mechanism of the enhanced antibacterial activity and offers insights for its application in water disinfection and antibacterial treatment.