Sterilization of Escherichia coli by Photothermal Synergy of WO3–x/C Nanosheet under Infrared Light Irradiation

The application of photocatalytic sterilization technology for the sterilization of water has been broadly studied in recent years. However, developing photocatalysts with high disinfection efficiency remains an urgent challenge. Tungsten trioxide with coexisting oxygen vacancies and carbon coating (WO3–x/C) has been successfully synthesized toward the photothermal inactivation of Escherichia coli. Oxygen vacancies and carbon coating bring WO3–x/C strong absorption in the infrared region and enhance the carrier separation efficiency. As a result, a higher sterilization rate is obtained compared to WO3. WO3–x/C can completely inactivate E. coli under infrared light within 40 min through photothermal synergy process. During the process of inactivating bacteria over WO3–x/C, E. coli is killed by the destruction of their cell membrane to decrease the activity of enzymes and release the cell contents, which can be ascribed to the efficient generation of reactive oxygen species (O2•– and •OH) and thermal effect. This work demonstrates a novel approach for engineering efficient and energy-saving catalysts for water sterilization.