A facile one-pot green synthesis of reduced graphene oxide and its composites for non-enzymatic hydrogen peroxide sensor applications

Abstract

A simple, environmental benign, time and cost-efficient green approach has been proposed for the reduction of graphene oxide (GO) and the synthesis of reduced GO (rGO)/mono and bimetallic composites using Azadirachta indica extract. The high crystallinity and face-centred-cubic structure of monometallic silver (Ag) and bimetallic silver–gold (Ag–Au) nanoparticles anchored over rGO were determined from the X-ray diffraction patterns. The functional groups involved in the reduction of GO and metallic precursors were identified by the Fourier transform–infrared spectroscopic technique. The obtained morphological images revealed a homogeneous distribution of spherical shaped Ag/Ag–Au nanoparticles with a narrow size distribution anchored over the rGO sheets. The prepared nanostructures exhibited significant electrocatalytic activities towards the reduction of hydrogen peroxide (H₂O₂), leading to a non-enzymatic electrochemical sensor with a prompt amperometric response. The non-enzymatic sensor responded linearly (R² = 0.9970) to the concentration of H₂O₂ over a range of 0.1 to 5 mM with a low level detection limit of 1 μM.