Z-scheme Heterojunction on TS-1 Zeolite Boosting Ultrafast Visible-Light-Driven Degradation of Cr(VI) and Tetracycline

Photocatalysis has emerged as a promising strategy to address water pollution caused by heavy metals and antibiotics. Zeolites exhibit significant potential in petrochemical catalysis; however, the development of zeolite-based photocatalysts remains a critical challenge for researchers. Herein, a novel Z-scheme heterojunction was designed and fabricated on the titanium-silicon zeolite TS-1 by modifying g-C₃N₄ via a simple calcination process. Compared to pure TS-1 or g-C₃N₄, the Z-scheme heterojunction of g-C₃N₄-TS-1-0.5 demonstrated enhanced light absorption and reduced electron-hole recombination rates, leading to an improved photocatalytic efficiency. Under visible light irradiation, g-C₃N₄-TS-1-0.5 exhibited exceptional photocatalytic performance, achieving rapid degradation of Cr(VI) (99.9% in 5 min) and tetracycline (80% in 15 min), outperforming its individual components. The stability of g-C₃N₄-TS-1-0.5 was further confirmed through anti-interference and cycling experiments. Theoretical calculations combined with radical trapping experiments verified the effect of Z-scheme heterojunction and identified superoxide radicals (·O₂^-) as the primary active species. Consequently, a plausible photocatalytic mechanism for g-C₃N₄-TS-1-0.5 was proposed. This work not only expands the possibilities for zeolite-based heterojunctions but also provides valuable insights into the photocatalytic degradation of environmental pollutants.