Urchin-like fibrous red phosphorus as an efficient photocatalyst for solar-light-driven disinfection of E. coil

Fibrous red phosphorus (FRP), a crystalline allotrope of red phosphorus has interesting structural features and promising applications in the area of energy storage devices and photocatalysis. In this work, we employ a solid state method to synthesize crystalline red phosphorus which results in an interesting urchin-like structure. The microstructure shows a bundle of fibers originating from a core. Detailed characterization points to the presence of FRP as the major allotrope in the product. Photocatalytic activity of FRP is examined towards the solar disinfection of water using E. soli as a model pollutant. The bandgap of the synthesized FRP is 1.9 eV and it has optimum valence band and conduction band levels to generate reactive oxygen species (ROS) such as superoxide radical and H2O2. OH is then produced from the H2O2. These photo-generated ROS are successful in bringing 8 log reduction in the concentration of E. coil in 30 min, which compares extremely well with values reported from other catalysts.