Two Birds With One Stone: A Novel Nanocomposite Combining Silicon Nanoparticles and Carbon-Doped Titania as the Fluorescence Probe and Visible Light Photocatalyst for Simultaneous Detection and Removal of Oxytetracycline

The monitoring and removal of environmental pollutants are vital for the sustainable development of society. Herein, a novel nanocomposite combining silicon nanoparticles and carbon-doped titania, C-TiO 2 /SiNPs, is designed as a fluorescence probe and visible-light photocatalyst to simultaneously monitor and degrade oxytetracycline (OTC). C-TiO 2 /SiNPs emit blue fluorescence, which can be quenched by OTC through inner filter effect. Meanwhile, green fluorescence is turned on upon OTC addition by aggregation-induced emission. Thus, C-TiO 2 /SiNPs successfully act as a fluorescence colorimetric probe for quantitation and semi-quantitation of OTC. Additionally, C-TiO 2 /SiNPs show adorable visible-light photocatalytic activity toward OTC, achieving a removal rate of 93.3% in 30 min. This process is driven by the superoxide radicals, holes and hydroxyl radicals produced by C-TiO 2 /SiNPs under visible light irradiation. The total toxicities obviously reduce after OTC is degraded by C-TiO 2 /SiNPs. The concentration during the OTC degradation can be estimated by naked eyes through the change of fluorescence color, but also precisely quantified by a fluorometer. This study innovatively develops a one-stone-two-birds strategy to achieve simultaneous degradation and in situ real-time detection of OTC, paving a promising paradigm for the highly efficient monitoring and removal of residual drugs.