MOF/COF heterostructure hybrid composite-based molecularly imprinted photoelectrochemical sensing platform for determination of dibutyl phthalate: A further expansion for MOF/COF application

A novel metal-organic framework (MOF)/covalent-organic framework (COF) heterostructure hybrid composite (NH2-UiO-66/TpPa-1-COF) with excellent photoactivity was developed, which further acted as the photoelectrochemical sensitized layer of a molecularly imprinted photoelectrochemical (MIP-PEC) sensor for extremely sensitive and selective determination of dibutyl phthalate (DBP). The NH2-UiO-66/TpPa-1-COF was synthesized using a simple one-step solvothermal method, which showed improved photocurrent response owing to heterojunction formation, favorable energy-band configuration and strong light absorption capacity. To improve the sensing performance, molecularly imprinted polymer (MIP) was developed by sol-gel polymerization method as the recognition component of PEC sensor. The specific binding of imprinting sites towards DBP could block the electron transfer, causing decreased photocurrent response of the MIP-PEC sensor. The MIP-PEC sensor showed a wide detection range from 0.1 nmol L-1 to 100 μmol L-1 with a limit of detection of 3.0 × 10-11 mol L-1 under optimal conditions. Meanwhile, the proposed MIP-PEC sensor showed good stability, selectivity, reproducibility, and applicability in real samples. This is the first attempt to apply MOF/COF heterostructure hybrid composite for MIP-PEC sensor construction, providing new insight into the potential applications of microporous crystalline framework heterostructure hybrid composite in the sensing field.