The construction of high efficient visible-light-driven 3D porous g-C3N4/Fe3O4 photocatalyst: A new photo-induced bacterial inactivation material enhanced by cascade photo-Fenton reaction

Photocatalytic disinfection is considered a promising method for eliminating the hazards of pathogenic bacteria. Graphitic carbon nitride (g-C3N4) is an ideal photocatalytic bacterial inactivation material for its advantage of tunable band structure, good stability and easy preparation. This work has constructed a novel defective 3D porous g-C3N4 by cyanamide carbonation using dendritic mesoporous silica template. The direct loading of Fe3O4 nanoparticles provided an excellent pg-C3N4-Fe3O4 photocatalyst suitable for water disinfection. Compared to pristine g-C3N4, the prepared 3D porous defective g-C3N4-Fe3O4 exhibited the enhanced visible light absorbance as indicated by the band gap decreasing of 0.66 eV, and about 3 and 10 fold increase of photo-induced current response and O2 adsorption respectively. The pg-C3N4-Fe3O4 showed excellent visible-light-driven photo -catalytic bactericidal activity. It could kill 1 x 107 cfu mL-1 Escherichia coli completely within 1 h under visible -light illumination (100 mW cm -2) with good reusability, its logarithmic bacterial inactivation efficiency was about 2.5 fold higher than pg-C3N4. The enhanced bactericidal performance is mainly ascribed to the Fe3O4 involved cascade photo-Fenton reaction.

Automated summary

Photocatalytic disinfection using graphitic carbon nitride (g-C3N4) is a promising method for eliminating pathogenic bacteria. In this study, a novel defective 3D porous g-C3N4-Fe3O4 photocatalyst was constructed using a dendritic mesoporous silica template. The photocatalyst exhibited enhanced visible light absorbance, increased photo-induced current response and O2 adsorption compared to pristine g-C3N4. The pg-C3N4-Fe3O4 photocatalyst showed excellent visible-light-driven photo-catalytic bactericidal activity, with a bactericidal efficiency 2.5 times higher than pg-C3N4. This enhanced performance is attributed to the involvement of Fe3O4 in cascade photo-Fenton reaction.