Simultaneous photocatalytic degradation and SERS detection of tetracycline by self-sustainable and recyclable ternary PI/TiO2/Ag flexible microfibers

Abstract

Abstract Facile and highly efficient photocatalysts under sunlight irradiation, as well as fast and sensitive surface-enhanced Raman spectroscopy (SERS) substrate are in urgent needs for practical degradation of tetracycline (TC). In order to meet the aforementioned requirements, a new paradigm of PI/TiO2/Ag organic-inorganic ternary flexible microfibers based on semiconductor oxide titanium dioxide (TiO2), noble metal silver (Ag) and conjugated polymer polyimide (PI) are successfully developed via engineering an easy method. Under sunlight illumination, the photocatalytic characteristics of PI/TiO2/Ag flexible microfibers with varying loadings of Ag quantum dots (QDs) are evaluated by investigating their photocatalytic degradation of TC aqueous solution. The results demonstrate that the concentration of Ag largely affected the photocatalytic activity. Among the tested samples, PI/TiO2/Ag-0.07 (93.1%) exhibited superior photocatalytic degradation performance compared to PI/TiO2 (25.7%), PI/TiO2/Ag-0.05 (77.7%), and PI/TiO2/Ag-0.09 (63.3%). This observation is strongly supported by the charge transfer mechanism discussions and evaluations conducted in the present work. Moreover, the PI/TiO2/Ag-0.07 flexible microfibers exhibit highly sensitive SERS detection capabilities, as demonstrated by the clear observation of Raman characteristic peaks even at an extremely low concentration of 10− 10 moles per liter for TC. The excellent photocatalytic performance and SERS detection capability of PI/TiO2/Ag flexible microfibers not only from the Schottky barrier formed between Ag and TiO2, but also from the outstanding plasmonic resonance and visible light absorption properties of Ag, along with the immobilization capability of PI. The successful synthesis of PI/TiO2/Ag flexible microfibers hold significant promise for advancing the fields of sensitive detection and efficient photocatalytic degradation of antibiotics.