Synergistic augmentation and rapid elimination of ciprofloxacin using a novel mesoporous nickel sulfide-adorned bismuth tungstate S-scheme heterojunction

Abstract

Pharmaceutical contamination hazardously threatens the health of human beings and the ecological system. Heterogeneous photocatalysis provides a marvelous and effective strategy for directly breaking down these harmful contaminants during visible light exposure in the presence of a semiconducting photocatalyst. Even so, this approach is considerably challenged by inadequate photo-harvesting and swift recombination rates for photo-induced charge carriers of traditional photocatalysts. In this investigation, a novel NiS/Bi2WO6 step (S)-scheme heterostructure photocatalyst was constructed by surfactant-assisted sol-gel methodology and applied for ciprofloxacin (CIPF) oxidation beneath visible-light illumination. The Bi2WO6 catalyst was successfully decorated with diverse contents of NiS nanoparticles (NPs) to investigate their impact on the overall characteristics and catalytic performance of bismuth tungstate. The optimal photocatalyst, 9.0 wt% NiS/Bi2WO6, revealed astounding efficacy in CIPF elimination from water solution, with 100.0% degradation efficacy within 90-min visible light exposure. This novel photocatalyst achieved a degradation rate of ca. 0.966 μmol min−1, surpassing that attained employing bare Bi2WO6 by ∼8.0 times. Moreover, 9.0 wt% NiS/Bi2WO6 heterostructure has exhibited superior strength and stability with 98.0% sustainability. This outstanding improvement in photocatalytic proficiency and performance with high sustainability could be attributed to the enhanced transfer and separation rates of light-induced carriers occurring through the S-scheme route. This novel heterojunction design also enlarged the visible light-harvesting responsiveness. This study offers new insights into the design and building of promising S-scheme heterostructure photocatalytic systems for highly efficient solar conversion applications.