Synergistically enhanced electrochemical sensor based on a covalent organic framework/carbon nanotube composite for...

An electrochemical sensor was developed for the sensitive voltammetric determination of 4-nitrophenol (4-NP) by integrating an in situ grown nanocomposite of amino-functionalized carbon nanotubes (NH₂-CNTs) and a zinc porphyrin-tetrathiafulvalene covalent organic framework (TTCOF-Zn). This hybrid design strategically couples the electron donor-acceptor (D-A) architecture of TTCOF-Zn, featuring pre-engineered electron transport channels, with the exceptional electrical conductivity of NH₂-CNTs via covalent bonding, synergistically enhancing charge transfer efficiency. Leveraging the high conductivity, abundant active sites, and hierarchical porosity of the TTCOF-Zn/NH₂-CNTs nanocomposite, the modified electrode achieves an exceptional detection limit of 17 nM (linear range, 50 nM-1 mM) using differential pulse voltammetry, surpassing most reported sensors. The sensor also demonstrates excellent reproducibility, long-term stability, and strong anti-interference capability against common co-existing species. Its practical applicability was demonstrated through quantitative analysis of 4-NP in real lake water samples, with results validated by the HPLC method, underscoring the potential of D-A COF/CNT covalent hybrids for high-performance environmental monitoring.