Highly Sensitive Amperometric Sensor Based on Gold Nanoparticles Polyaniline Electrochemically Reduced Graphene Oxide Nanocomposite for Detection of Nitric Oxide

A sensitive electrochemical sensor was fabricated for selective detection of nitric oxide (NO) based on electrochemically reduced graphene (ErGO)-polyaniline (PANI)-gold nanoparticles (AuNPs) nanocomposite. It was coated on a gold (Au) electrode through stepwise electrodeposition to form AuNPs-PANI-ErGO/Au electrode. The AuNPs-PANI-rGO nanocomposite was characterized by Field Emission Scanning Electron Microscopy (FESEM) and UV-vis. Electrochemical behavior of modified electrode was analyzed by cyclic voltammetry (CV) and chronoamperometry (CA) techniques. CVs of AuNPs-PANI-ErGO/Au, PANI-ErGO/Au and ErGO/Au electrodes showed that conductivity of AuNPs-PANI-ErGO/Au was higher than others. Nafion was used to improve selectivity of modified electrode. Nafion/AuNPs-PANI-ErGO/Au electrode represented favorable electrochemical and electrocatalytic behavior towards NO oxidation. The resultant electrode exhibited a high sensitivity of 0.113 μA/μM over a wide linear range from 0.8 × 10^−6 to 86 × 10^−6 M with a low detection limit of 2.5 × 10^−7 M (S/N=3). In addition, the sensor had excellent stability, as well as reproducibility and selectivity, which makes it possible to detect NO quickly and accurately.