Efficient Amperometric Detection of H₂O₂ using Gold Nanoparticle decorated Polythiophene/Hematite Ore Nanocomposite

Abstract

We have developed a cheap and sensitive H2O2 electrochemical sensor. Herein we fabricated the electrochemical sensor electrode using a naturally extracted hematite ore decorated with conducting polythiophene (Pth) and gold nanoparticles (AuNPs). A simple synthesis route was adopted for the electrocatalyst synthesis using ultrasonication followed by photo-reduction. The as-fabricated Au@Pth/Hematite Ore nanocomposite was successfully characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and field-effect transmission electron microscopy techniques. Obtained results reveal that un-doped naturally-extracted hematite ore is composed of Fe2O3 and Fe3O4 phases. The catalytic efficiency of the newly-designed nanocomposite and its sensing ability towards H2O2 were assessed using electrochemical techniques including electrochemical impedance spectroscopy, cyclic voltammetry, linear sweep voltammetry, and highly-sensitive amperometric (i-t) techniques. The Au@Pth/Hematite Ore/GCE sensor showed a wide linear dynamic range of 0.5–9.50 mM with high sensitivity of 69.18 μAmM- 1cm- 2. The limit of detection was estimated to be 5.18 µM. The examined sensor revealed acceptable reproducibility, repeatability, and stability. The examined sensor electrode also showed anti-interference behaviour in the presence of different interfering ions or molecules during the H2O2 determination. Moreover, the proposed sensor exhibits acceptable recovery of H2O2 in real sample analysis.