Green synthesis of Oscimum Sanctum mediated silver nanoparticles to fabricate sensors for hydrogen peroxide detection

Abstract

In this study, silver nanoparticles (Ag NPs) of an average size of ∼15 nm have been produced using the green synthesis technique with Oscimum Sanctum leaf extract. Further, these nanoparticles have been used to prepare electrodes for electrochemical sensors to monitor hydrogen peroxide. Hydrogen peroxide sensors have many applications in different sectors, such as medical, agriculture, and industry. The optical and structural characteristics of the Ag NPs have been investigated by UV–visible absorption spectroscopy and XRD patterns. Particle size, shape, and morphology of as-synthesized Ag NPs have been analyzed using transmission and scanning electron microscopic techniques. These nanoparticles were deposited onto an indium-tin-oxide glass substrate using the electrophoretic technique, which was used as an electrode to assess the electro-oxidation of Ag NPs by cyclic voltammetry. The sensitivity of the sensor has been estimated to be 4.16 µA/mM-cm2. The limit of detection of the sensor is estimated to be 40 µM within the linear range of 5–28 mM. The lattice parameter, interplanar spacing, and crystallite size of Ag NPs have been quantified and estimated against pH variation.