Effective degradation of antibiotics using near-infrared excited nonlinear optical heterojunctions through atomic-level regulation

Abstract

Developing an efficient photocatalyst that fully utilizes sunlight, especially near-infrared light, remains a major challenge. Here, a synthesis strategy for producing g-C₃N₄:Tm@Ba₄Yb₃F₁₇:Tm Z-scheme composites with infrared light response composed of single atom Tm modified g-C₃N₄ nanosheets and Ba₄Yb₃F₁₇:Tm nanoparticles were proposed. The formation of Z-scheme heterojunctions was demonstrated by combining DFT and fs-TAS. More importantly, not only is the critical distance for energy transfer between Yb³⁺ and Tm³⁺ precisely controlled, but the distance required for upconversion luminescence emitted from Tm³⁺ to be transmitted to g-C₃N₄ is also precisely adjusted at the molecular level, allowing the upconversion luminescence emitted by Tm³⁺ to be more effectively transmitted to g-C₃N₄. Under near-infrared light, the ultraviolet and blue upconversion emissions generated by Ba₄Yb₃F₁₇:Tm can be fully absorbed by g-C₃N₄ and generate electron–hole pairs (e⁻/h⁺), achieving efficient energy transfer and exhibiting significant performance in the degradation of antibiotics. After 12 hours of near-infrared light exposure, the degradation efficiency of tetracycline reached 93%. The mechanisms of reaction intermediates, active species, and reaction pathways during the catalytic process have been proposed based on LC-MS/MS technology. This work provides a new scenario for the design and synthesis of catalysts with near-infrared light response characteristics.