Synthesis of silver nanoparticles decorated on reduced graphene oxide nanosheets and their electrochemical sensing towards hazardous 4-nitrophenol

Abstract

In this study, an electrochemical sensor for the detection of 4-Nitrophenol (referred to as 4-NP) was developed based on templated silver nanoparticles (AgNPs) on reduced graphene oxide (rGO) nanosheets (Ag-rGO) and utilized as an electrocatalyst. It was found that the resulting composite exhibits enhanced catalytic activity towards the reduction of 4-NP. The cubic shaped AgNPs templated on rGO nanosheets has been successfully fabricated by a chemical reduction method using sodium borohydride (NaBH4), and it was well characterized through morphological and electrochemical techniques: Ultraviolet–Visible spectroscopy (UV -Vis), scanning electron microscopy (SEM) equipped with energy-dispersive spectroscopy (SEM–EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), cyclic voltammetry (CV), and chronoamperometry. The obtained results revealed that the AgNPs scattered on rGO sheets are spherical in shape, and it’s estimated to be a dimension of ~ 60 nm in size. The prepared crystalline Ag-rGO nano sheets were further applied as an electrode material for the electrochemical examination with three electrode system to sense the hazardous material 4-NP in PBS. The electrochemical studies were conducted through CV under the condition of bare and coated electrode (Ag-rGO/GCE) with influence of concentration (4-NP from 2 to 150 mM), scan rate, reproducibility (RSD-2.87%) and stability test (4-NP-20 µM) were examined. The data reveal that the Ag-rGO/GCE exhibit highly reproducible and sustainable for the reduction of toxic 4-NP. The chronoamperometry study for current and time response was also studied at two different potentials (− 0.3 V & − 0.6 V), respectively.