In situ polymerization synthesis of polyaniline/strontium niobate nanocomposite for highly sensitive electrochemical detection of catechol

Catechol shows a wide range of applications in real life, but it has been considered as an organic pollutant due to its potential harm to the ecological environment and human health, so the monitoring of catechol is particularly important. In this work, an electrochemical sensor for the detection of catechol was developed based on an organic/inorganic layered nanocomposite polyaniline/strontium niobate (PANI/HSr2Nb3O10) synthesized by in situ polymerization. Some characterization methods such as X-ray diffraction patterns, scanning electron microscope, high-resolution transmission electron microscope, X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy were systematically used to evaluate the structure, composition, and morphology of the as-prepared samples. Compared with other single component modified electrodes, PANI/HSr2Nb3O10/GCE can accelerate the electron transfer ability and possess larger electroactive surface area due to the synergistic effect of PANI and HSr2Nb3O10, which resulted in enhanced electrocatalytic activity toward catechol. A pair of well-defined redox peaks observed on PANI/HSr2Nb3O10/GCE correspond to the redox process of catechol, the mechanism of which is a reversible conversion between catechol and quinone. Under optimized conditions, the differential pulse voltammetry was performed for the detection of catechol, and the detection limit of 0.02 μM was obtained in the concentration range of 0.025–4.97 mM. Additionally, the developed electrochemical sensor also exhibits satisfied repeatability, long-term stability, reproducibility, and anti-interference and shows practicality in environmental water samples, which further reveals the feasibility of the sensor for practical applications.