Sustainable solar-induced decontamination of waterborne pharmaceutical pollutants using a structurally engineered Ti3C2 MXene/Bi2MoO6/g-C3N4 S-scheme heterocatalyst with tri-component interfacial charge transfer.

Abstract

The persistence of pharmaceutical pollutants in aquatic environments poses significant threats to ecosystems and public health, thereby necessitating the development of highly efficient photocatalysts for their removal. In this study, a novel 2D/2D/2D ternary heterostructure comprising Ti₃C₂ MXene (TC), Bi₂MoO₆ (BMO), and g-C₃N₄ (CN) was rationally engineered to achieve superior solar-driven photodegradation of waterborne pharmaceutical contaminants. The optimized TC/BMO-15/CN hybrid exhibited outstanding degradation efficiencies of ∼100% for cefixime in 90 min and 99% for naproxen in just 30 min, significantly outperforming pristine CN, BMO, and the binary BMO-15/CN photocatalyst. Comprehensive structural, optical, and electrochemical characterizations revealed that the synergistic integration of TC as a conductive bridge-combined with the optimal BMO content and intimate interfacial coupling-enhanced light harvesting, facilitated efficient tri-component interfacial charge transfer, and prolonged charge carrier lifetimes. Mechanistic investigations using reactive species quenching, ESR spectroscopy, and in situ light-irradiated XPS confirmed the formation of an S-scheme heterojunction, which enables selective spatial retention of high-energy charge carriers for redox reactions. By uniting architectural synergy with S-scheme charge transfer, the system enhances charge dynamics and enables efficient mineralization of complex pharmaceutical pollutants. Furthermore, the TC/BMO-15/CN catalyst demonstrated excellent structural stability and maintained high degradation performance across various water matrices and multiple reusability cycles. This study offers valuable insights into heterointerface engineering and presents a strategic platform for designing high-performance photocatalysts for practical environmental remediation applications.