Metal–Reduced Graphene Oxide-based Nanocomposites: Synthesis, Characterization, and Sensing Applications

Abstract

Graphene is a carbon allotrope; a single layer of carbon atoms arranged in a hexagonal lattice structure makes it the thinnest and strongest 2D material. However, graphene alone cannot be used directly for many applications. Graphite (multilayer graphene sheets), when introduced to oxidation, gives graphene oxide (GO), which has oxygen-containing functional groups and can integrate metal nanoparticles. Metal attaches to GO sheets both electrostatically and covalently by GO–COOH groups that undergo simultaneous reduction to form metal–reduced graphene oxide (M-rGO) nanocomposites. Syntheses of M-rGO nanocomposites include solvothermal processes, hydrothermal processes, UV-assisted photocatalytic and chemical reduction, microwave irradiation, sol-gel, and self-assembly. The nanocomposite characterization is essential to study the structural and chemical properties like core morphologies, crystallographic structure, electronic state, disorder, and defects. The M-rGO provides benefits like enhanced peroxidase-like catalytic activity, high surface area, electrical conductivity, thermal stability, and optical property. These exquisite properties make it a better platform for sensing environmental pollutants, and metabolites including biologically important analytes with high specificity and selectivity. This chapter discusses the synthesis processes, characterization techniques, and sensing applications for environmental pollutants and biologically relevant molecules/species using metal–rGO-based nanocomposites.