Design of Ag@ZnO@Ti3C2 MXene heterojunction photocatalyst for enhanced photocatalytic degradation activity of methylene blue and levofloxacin under visible light irradiation

Abstract

A ternary Ag@ZnO@Ti3C2 MXene heterojunction (AZM) is synthesized by hybridizing ZnO and Ag nanoparticles with the MXene via a simple hydrothermal and chemical deposition method. The addition of ZnO and Ag can effectively compensate for MXene’s narrow bandgap property, promote charge carrier separation, and improve visible light absorption, thereby enhancing photocatalytic activity. The photocatalytic activity of the AZM is evaluated through the removal efficiency of methylene blue (MB) dye and levofloxacin (LVX) under visible light irradiation. The results show that the optimized ternary AZM heterojunction photocatalysts (AZM-15) possesses the maximum degradation of MB (90.54%) with a reaction rate constant of 0.0473 min−1, while the maximum degradation of LVX (86.76%) has a reaction rate constant of 0.0408 min−1. Moreover, the AZM composite exhibits excellent stability, which explains its MB removal rate of 83.59% and LVX removal rate of 80.03% after five cycles. The results of trapping experiments and EPR demonstrated that the main active species in the MB and LVX photodegradation process are·OH and·O2-. This work not only elucidates a possible mechanism of photocatalytic degradation of organic pollutants but also provides a pathway to design new bandgap photocatalysts for mitigating environmental pollution.