Black phosphorus/graphitic carbon nitride: A metal-free photocatalyst for “green” photocatalytic bacterial inactivation under visible light

[Display omitted] •Metal-free BP-CN photocatalyst was simply prepared and firstly used for photocatalytic bacterial inactivation.•The BP-CN photocatalyst showed a ~7 times better log inactivation efficiency of the E. coli compared with that of pure CN.•Metal-free BP showed great promise to replace noble metals for photocatalytic water disinfection.•The mechanism of enhanced disinfection activity was systematically investigated. In the drive toward the ever-increasing standards for high-quality drinking water, exploring stable and efficient photocatalysts with excellent visible light (VL) harvesting ability for the photocatalytic water disinfection is still a challenging problem. However, most photocatalysts are solely metal-based or contain at least one metal-containing cocatalyst with detrimental environmental impacts. Here, we show that a novel metal-free 2D heterostructure (BP-CN) composed of black phosphorus (BP) and graphitic carbon nitride (CN) can be used as a VL-driven photocatalyst to achieve highly efficient water disinfection. The activity of BP-CN photocatalyst was about 7 times better compared with that of pure CN for the disinfection of indicator bacteria, with the complete inactivation of bacterial cells (107 cfu·mL−1) within 60 min. The bacterial inactivation mechanism was thoroughly investigated, and hydroxyl radical (OH) and H2O2 were determined to be the major reactive oxygen species (ROSs) for water disinfection. The BP-CN photocatalyst is composed of low-cost and earth-abundant materials and holds great promise in “green” photocatalytic disinfection applications.