A COF/Carbon Black-Based Electrochemical Sensor for Trace Catechol Detection in Tap and River Water

Catechol (CC), a typical toxic phenolic pollutant in aquatic environments, poses severe threats to ecology and human health, and an efficient sensing method for trace CC detection is urgently needed. Herein, a carboxyl-functionalized covalent triazine framework (CTF-2COOH) with a hierarchical flower-like porous structure was synthesized, and the morphological and structural characterizations systematically verified its favorable porous texture and large specific surface area. On this basis, a CTF-2COOH/carbon black (CB) composite was further prepared, and related tests confirmed the successful composite fabrication with a well-preserved porous architecture to fabricate an electrochemical sensor chip. CTF-2COOH offers a large specific surface area and abundant active sites, while CB enhances the composite’s conductivity, triggering remarkable synergistic electrocatalysis towards CC. The optimized sensor (75% CB content) presents an extended linear detection range of 0.1–100 μM, a low limit of detection of 80.7 nM, favorable selectivity, excellent repeatability, reproducibility, and long-term stability. It also realizes reliable CC detection in real tap water and river water with satisfactory recoveries of 90.2%–104.2%, owing to the reversible adsorption interaction between CTF-2COOH and CC. This work provides a high-performance sensing strategy for CC monitoring and a feasible reference for COF-based electrochemical sensor design.