Capsule-shaped nano silver-embedded reduced graphene oxide nanocomposites for sensing of mercury ions

Capsule-shaped nano silver-based reduced graphene oxide nanocomposites (RGO–Ag) are prepared using “one pot” synthetic protocol. Herein, we have taken tamarind leaf extract for the reduction of Ag⁺ ion which has been used towards the synthesis of RGO–Ag nanocomposites. Different temperature conditions are considered for the optimization of formation of nanoparticles. Scanning electron microscope (SEM) has been used to find out the micrograph of as-synthesized nanocomposites. From SEM image, capsule-shaped nanocomposites can be clearly observed. The as-synthesized nanocomposites display a better response to Hg²⁺(aq) in pH 4.0–10. There is negligible effect of other ions for the recognition of Hg²⁺ (aq) ion and, therefore, as-synthesized nanocomposites can be used for the sensitive and selective recognition of mercury (II) ion in aqueous phase. Since tamarind leaf extract has been used as reducing agent and water is used as solvent, it is a green and eco-friendly process. The recognition limit of Hg²⁺ ion in water sample is found to be 15 nM.