Mechanistic insights into antibiotic degradation using multicomponent 2D quasicrystals as robust photocatalysts via in situ TEM

The widespread presence of antibiotics such as sulfamethoxazole (SMX) and tetracycline (TC) in aquatic environments poses a significant threat to ecological safety. In this study, aluminum-based multicomponent alloys engineered into two-dimensional quasicrystals (2D QCs) are presented as a robust and reusable photocatalyst for visible-light-driven degradation of SMX and TC. The catalyst achieved degradation efficiencies of approximately 94% for SMX and 89% for TC within 2 hours. The photocatalytic activity was thoroughly examined under various conditions, including pH variations, catalyst dosage, pollutant concentration, and the influence of common inorganic ions. The 2D QCs demonstrated excellent reusability with negligible metal leaching across successive cycles. Notably, substantial degradation was also achieved in real water matrices such as tap water, pond water, and municipal wastewater, highlighting their environmental practicality. Furthermore, in situ liquid-phase transmission electron microscopy captured the real-time degradation of SMX antibiotic molecules on QC surfaces. Phytotoxicity assays with Vigna radiata confirmed that the treated effluents were non-toxic, as seed germination and root growth were comparable to those of the controls. This work identifies 2D QCs as a highly effective photocatalyst for antibiotic removal in complex water systems, addressing an urgent global challenge.