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

Abstract

In the present work, we developed a cheap and sensitive H2O2 electrochemical sensor. Herein we fabricated an 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, where Pth was synthesized through oxidative polymerization and then combined with Hematite Ore nanostructure via a simple ultrasonication process. Later a simple photo-reduction approach was used to develop a 1%Au@5%Pth/Hematite Ore nanocomposite. The as-fabricated Au@Pth/Hematite Ore nanocomposite was successfully characterized by applying X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), High-Resolution Transmission Electron Microscope (HR-TEM), and Field Emission Scanning Electron Microscope (FE-SEM) techniques. The obtained results reveal that undoped 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 (EIS), cyclic voltammetry (CV), linear sweep voltammetry (LSV) and highly sensitive amperometric (i-t) techniques. The Au@Pth/Hematite Ore/GCE sensor showed a wide linear dynamic range of 0.50–9.50 mM with high sensitivity of 69.18 μAmM−1cm−2. The limit of detection (LOD) was estimated to be 5.18 μM. The examined sensor demonstrated acceptable reproducibility, repeatability as well as stability. The sensor electrode also showed anti-interference behavior in the presence of different inorganic and organic interfering ions or molecules during the H2O2 determination. Moreover, the proposed sensor exhibits acceptable recovery of H2O2 in real sample analysis. Hence, this novel sensor is regarded as a promising contender in scientific and industrial domains.