Dual Function: Practical Nanomolar Antibiotic Detection and Photocatalytic Micropollutant Degradation Using Thiazolothiazole-Conjugated Microporous Polymers

Functional conjugated microporous polymers (CMPs) were studied for chemical sensing and photocatalytic application. However, CMPs showing dual functional properties of electrochemical sensing and photocatalytic activity are rare yet unique and are associated with the choice of building blocks. Herein, we demonstrate a dual-function conjugated microporous polymer, p TPETTz ( S BET = 331.8 m 2 g –1 ) and lp TPETTz ( S BET = 11.4 m 2 g –1 ), based on conducting and photo functional thiazolothiazole (TTz) units for selective detection of metronidazole (MNZ) and photocatalytic degradation of micropollutants. p TPETTz-modified electrodes (glassy carbon and screen-printed electrode) exhibited a selective current response to MNZ among other antibiotics, interfering biomolecules etc. Among them, p TPETTz@GC showed the lowest detection limit (LoD) of 5.74 nM. The p TPETTz@SPE showed similar detection limits as p TPETTz@GC in the urine sample analysis and showed a high recovery percentage. Interestingly, the sensing response of p TPETTz is significantly higher than that of lp TPETTz due to the lower charge transfer resistance ( R ct ) of p TPETTz (259.84 Ω cm 2 ) compared to lp TPETTz (360.41 Ω cm 2 ) and bare ITO (642.35 Ω cm 2 ) as evidenced by electrochemical impedance spectroscopy (EIS). Apart from this, p TPETTz ( E g = 2.41 eV) and lp TPETTz ( E g = 2.37 eV) also showed efficient photocatalytic degradation (up to 98.21%) of aqueous food colorants under direct sunlight due to the formation of a highly reactive species superoxide anion (O 2 •– ) and photogenerated holes ( h + ). The degradation follows pseudo-first-order kinetics with a relatively higher rate constant ( k = 0.05 min –1 ).