Solar driven photocatalytic disinfection by Z-scheme heterojunction of In2O3/g-C3N4: Performance, mechanism and application

To realize an efficient solar disinfection, Z-scheme In2O3/g-C3N4 heterojunctions were prepared and its performances were investigated. The In2O3/g-C3N4 exhibits a wide light response range and a low carrier recombination rate. Due to the transfer of electron (e-) and hole (h+) between In2O3 and g-C3N4, the generations of superoxide (O2•-) and hydroxyl radicals (HO•) were enhanced. O2•−, HO• and h+ played important roles for disinfection. Approximately 106 CFU/mL E. coli were inactivated within 90 min. In addition to cell membrane lysis, DNA was degraded. In2O3/g-C3N4 still revealed high sterilization efficiencies under natural sunlight or for actual wastewater treatment. Although humic acid and inorganic anions (Cl‾ < NO3‾ < SO42‾ < H2PO4‾ < HCO3‾) inhibited the disinfection, detection limit (DL, about 5.8-log removal) can be achieved. Furthermore, DL still could be achieved and the In2O3/g-C3N4 structure remained intact after 5 cycles. This study provides novel guidance for solar-driven water purification.