Construction of double S-scheme CeO2/BHN/I−-BiOIO3 heterojunctions for enhanced photocatalytic degradation of norfloxacin

Abstract

In this study, double S-scheme CeO₂/[Bi₆O₆(OH)₃](NO₃)₃·1.5H₂O (BHN)/I⁻-BiOIO₃ heterojunctions were constructed by a simple hydrothermal and calcination method, wherein the special layered structure of BiOIO₃ was employed for its I⁻ modification. The improvement in photocatalytic degradation efficiency was derived from the synergistic effect of the double S-scheme heterojunctions and I⁻ modification. In a photocatalytic degradation experiment with norfloxacin as the target pollutant, the degradation efficiency of the typical sample (CeO₂/BHN/I⁻-BiOIO₃-2) reached 97.50%, which is higher than that of CeO₂ and BHN/BiOIO₃. The CeO₂/BHN/I⁻-BiOIO₃ double S-scheme heterojunctions significantly enhanced the photocatalytic degradation ability of antibiotics in comparison with single-substance photocatalysts and simple two-phase composites. It is noteworthy that the CeO₂/BHN/I⁻-BiOIO₃ double S-scheme heterojunctions are also capable of achieving a degradation rate of up to 73.16% for norfloxacin in river water. Furthermore, this double S-scheme heterojunction demonstrated degradation efficiencies of approximately 90% for quinolone antibiotics, including ofloxacin, enrofloxacin, ciprofloxacin and gatifloxacin. This study offers a novel approach to enhancing the photocatalytic degradation of organic pollutants through double S-scheme heterojunctions and element modification.