Interfacial coupling of sandwich like Zn3V2O8/ZnO/NiCo2S4 nano-heterojunction for the enhanced photocatalytic degradation of rifampicin

Abstract

The overuse of antibiotics and the release of these pharmaceuticals into the water system has emerged as a serious issue posing a life-threatening environment to aquatic species. In contrast to various contaminants, antibiotics are specifically engineered for durability and efficacy in the system of the human body (human health). Although this design ensures their performance, it also results in their extended longevity and resilience against degradation in natural contexts. These challenges can be addressed by an advanced oxidation process (AOP) utilizing ternary heterojunction nano catalysts (NCs). In this study, the NCs were synthesized through a combination of calcinated-assisted reverse microemulsion and hydrothermal methods. The synthesized NCs were characterized by using various analytical techniques. The enhanced charge separation and migration in Zn₃V₂O₈/ZnO/NiCo₂S₄ (ZZN) NCs results in 97.3 % degradation of rifampicin (RIF) within 80 min. ZZN NCs exhibit superior catalytic performance under visible light irradiation compared to its pristine Zn₃V₂O₈, ZnO, NiCo₂S₄, and binary ZnO/NiCo₂S₄. The enhanced photocatalytic performance can be primarily attributed to the synergetic effects among Zn₃V₂O₈, ZnO, and NiCo₂S₄ facilitated by the cascade-driven charge transfer mechanism. The prominent reactive oxygen species that participated in photocatalytic degradation activity were found to be superoxide (O₂•^-) and hydroxide radicals (•OH) which were confirmed through ESR and quenching experiments. From the practical application perspective, ZZN NCs ternary heterostructure demonstrated excellent stability and durability after being recycled six times. This study serve as a vital reference for future investigation into the photocatalytic mechanism related to heterostructure NCs, highlighting their potential for eco-friendly methods to eliminate pollutants and paves a way for manufacturing innovation in near future.