Enhanced photoelectrochemical sensor for dopamine detection based on MOFs-derived ZnO and TpPa-1 heterostructure composite

Abstract

This study used ZIF-8 metal–organic framework as a precursor to create a N-doped ZnO. Subsequently, covalent organic framework named TpPa-1 (Tp, 1,3,5-triformylphloroglucinol; Pa-1, p-phenylenediamine) with a ZnO heterostructure composite (ZnO/TpPa-1) was created through an in-situ synthesis approach. Due to its superior band structure and outstanding photocatalytic performance, the ZnO/TpPa-1 composite is a good candidate for the development of a new type of photoelectrochemical (PEC) sensor for the detection of dopamine (DA). According to experimental data, ZnO/TpPa-1/ITO had a photocurrent that was roughly 1.5 times higher than TpPa-1/ITO and 4.5 times higher than ZnO/ITO. The primary reason for this improvement was the synergistic effects brought about by effective light usage and charge transfer at the interface between the TpPa-1 π-conjugated backbone and ZnO porous structure. The determination ranges for DA demonstrated two linear ranges, 0.005–0.25 μmol/L and 0.25–1.00 μmol/L, and the detection limit was as low as 1.3 nmol/L. Moreover, the PEC sensor exhibited good stability, selectivity, repeatability, and suitability for real-world samples. This work provides important new understandings for covalent organic framework (COF)-based heterostructure design, which can be used to improve PEC sensor performance.