MXene-mediated in situ formation of Schottky junction for selective and sensitive detection of antioxidant tertiary butylhydroquinone in edible oil

We developed a label-free photoelectrochemical (PEC) sensor based on MXene Ti3C2/TiO2-g-C3N4 synthesized by in situ oxidation for the selective detection of synthetic antioxidant tertiary butylhydroquinone (TBHQ). As a dual-function mediate, MXene can be oxidized to TiO2 and mediate in situ formation of Schottky junction, significantly accelerating migration of electrons. Besides, MXene can enhance visible light absorption of TiO2 due to its black colour and thus greatly improve the photocurrent response. Under visible light excitation, this PEC sensor exhibited high sensitivity, good stability, and reproducibility towards TBHQ analysis, with wide linear range from 0.125 µM to 521.3 µM and a detection limit of 15 nM. Moreover, it can selectively recognize TBHQ from antioxidants with similar structures without labelled techniques, mainly because TBHQ possesses a lower redox potential. This PEC was successfully applied to the detection of TBHQ in edible oils with accurate results.