Enhanced photocatalytic antibacterial and degradation performance by n-p type 0D/2D SnO2−x/BiOI photocatalyst under LED light

The construction of efficient and multifunctional photocatalyst with tight hybridization structure is an ideal method to remove pollutants from wastewater. To achieve the goal, a novel n-p type 0D/2D SnO2−x/BiOI photocatalyst was prepared by using large specific surface area SnO2−x (203.1 m2/g) combining with BiOI nanosheet through a facile in situ growth route. A series of techniques including TEM, HRTEM and BET confirmed the structure of 0D/2D SnO2−x/BiOI composite. As expected, the novel SnO2−x/BiOI photocatalyst can successfully remove tetracycline (TC), Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) under LED light. Photocurrent and EIS verified the enhanced separation efficiency of photo-excited electron-hole pairs. Trapping experiment and mass spectrometry analysis revealed the active species, intermediate product and photodegradation pathway in photocatalytic process. The mechanism reveals that the Fermi levels of n-type SnO2−x and p-type BiOI have reached a new equilibrium, which is conducive to charge separation of electrons and holes. This work provides an effective example for the preparation of compact heterojunction photocatalytic materials with high efficiency.