Graphitic Carbon Nitride Nanoflakes Decorated on Multielement-Doped Carbon as Photocatalysts for Bacterial Disinfection under Visible and Near-Infrared Light

Preparing photocatalyst-based graphitic carbon nitrides that have a broad active spectrum for energy and environmental applications remains a huge challenge. Sub-10-nm graphitic carbon nitride has become an attractive photocatalyst because of its impressive optical and electronic properties, strong quantum confinement, and an edge effect that converts near-infrared (NIR) into visible (vis). Herein, a photocatalyst with a broad active spectrum from vis (400–800 nm) to NIR (800–2500 nm) was prepared through the self-assembly of graphene-like graphitic carbon nitride nanoflakes decorated on multielement-doped carbon (g-C3N4NFC) for bacterial disinfection. The as-prepared g-C3N4NFC exhibited unique physical and chemical properties and a broad light absorption spectrum from the vis to NIR region. The g-C3N4NFC promoted high photocatalytic disinfection toward Escherichia coli and Staphylococcus aureus under vis and NIR exposure, while the conventional graphitic carbon nitride photocatalyst showed low catalytic activity and was not active under NIR radiation. The authors attribute this effect to the wide spectrum harvesting and inhibition of charge recombination caused by the ultrasmall size of g-C3N4NF and the introduction of multielement-doped carbon, respectively. The bactericidal mechanism occurred via the destruction of the cell membrane, which was confirmed by the leakage of intercellular cell components after direct contact with holes generated from photocatalytic activity on the catalyst surface in the presence of oxygen. The photocatalytic activity was essentially unchanged when the catalyst was reused five times, highlighting its excellent stability.