Constructing an S-scheme CuBi2O4/Bi4O5I2 heterojunction for lightemittingdiode-driven pollutant degradation and bacterial inactivation

A novel S-scheme CuBi2O4/Bi4O5I2 heterojunction was synthesized by hydrothermal and following calcination route. The photocatalytic performance was estimated by removing four different pollutants (TC, BPA, RhB, and MO) and two kinds of bacteria (E. coli and S. aureus) under LED light. The optimum sample 37% CuBi2O4/Bi4O5I2 can degrade 81% tetracycline (TC) within 90 min, and can inactivate 100% E. coli in 20 min and S. aureus in 40 min. h+, •OH and •O2− are active species in the photocatalytic process. The synergistic effect of S-scheme heterojunction makes it possess excellent photocatalytic activity. [Display omitted] The CuBi2O4/Bi4O5I2 S-scheme heterojunction structure was constructed by a hydrothermal and subsequent calcination route. The combination of CuBi2O4 and Bi4O5I2 produced excellent photocatalytic performance under an LED light. A series of technical characterizations, including X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), were used to determine the successful construction of S-scheme CuBi2O4/Bi4O5I2 composites. The improvement of photogenerated carrier separation efficiency helped to achieve the best photocatalytic performance of 37% CuBi2O4/Bi4O5I2, which can degrade tetracycline (TC) to 81.67% in 90 min, and completely inactivate Escherichia coli (E. coli) in 20 min and Staphylococcus aureus (S. aureus) in 40 min. The effects of some key parameters (such as the concentration of pollutants, the amount of catalyst, pH value of a solution, various inorganic anions and various water substrates) and the possible degradation path of tetracycline were systematically studied. Finally, the removal of pollutants and inactivation of bacterial mechanisms based on the S-scheme heterojunction (CuBi2O4/Bi4O5I2) was proposed. This study provides insight into the synthesis of S-scheme heterojunction photocatalysts, which can efficiently degrade organic pollutants and inactivate bacteria under LED light irradiation.