The highly sensitive electrocatalytic sensing of catechol using a gold/titanium dioxide nanocomposite-modified gold electrode

Abstract

A Au@TiO₂ nanocomposite-modified gold electrode (Au@TiO₂ NP/gold electrode) has been exploited to study the electrochemical behavior of catechol (CC) using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The as-prepared Au@TiO₂ NP/gold electrode exhibits excellent electrochemical catalytic activity toward the oxidation of CC. Compared with the results obtained from the bare gold electrode and the TiO₂ nanocomposite-modified gold electrode (TiO₂ NP/gold electrode), the oxidation potentials of CC at the Au@TiO₂ NP/gold electrode decrease significantly, and the corresponding oxidation currents increase remarkably. In addition, the separation between the peak potential and the peak current for CC in pH 7.38 phosphate buffer solution (PBS) increased, making it suitable for the selective detection of CC. Under optimized conditions, CC was determined by differential pulse voltammetry (DPV), and the electrode exhibited a linear response over the range of 1.0 μM to 100.0 μM with a correlation coefficient of 0.9996. Furthermore, the limit of detection was 0.075 μM (S/N = 3), indicating high sensitivity for the electrocatalytic sensing of CC. The interference, reproducibility and stability of the measurements were also favorable, with a high retention rate of 92% of the peak current after 30 days. The resulting Au@TiO₂ NP/gold electrode, which is highly sensitive, reproducible and stable, will provide important improvements for electrochemical sensors in applications for environmental and chemical engineering, including, but not limited to, the detection of CC.