Sensing platform for the highly sensitive detection of catechol based on composite coupling with conductive...

Catechol, which has a high toxicity and low degradability, poses significant risks to both human health and the environment. Tracking of catechol residues is essential to protect human health and to assess the safety of the environment. We constructed sensing platforms to detect catechol based on the conductive metal-organic frameworks [Ni₃(HITP)₂] and their nanosilver composites. The reduction process of catechol at the Ni₃(HITP)₂/AgNP electrode is chemically irreversible as a result of the difference in compatibility of the oxidation stability and conductivity between the Ni₃(HITP)₂/AgNS and Ni₃(HITP)₂/AgNP electrodes. The electrochemical results show that the Ni₃(HITP)₂/AgNS electrode presents a lower detection limit of 0.053 μM and better sensitivity, reproducibility and repeatability than the Ni₃(HITP)₂/AgNP electrode. The kinetic mechanism of the catechol electrooxidation at the surface of the electrode is controlled by diffusion through a 2H⁺/2e^- process. The transfer coefficient is the key factor used to illustrate this process. During the electrochemical conversion of phenol to ketone, more than half of ΔG is used to change the activation energy. We also studied the stability, anti-interference and reproducibility of these electrode systems.