Ag–SiO2 nanocomposite for the optical detection of Hg(II) ions and catalytic reduction of methylene blue

Abstract

The adverse impact of heavy metal ions as well as dye effluents is the genuine threat to the environment. We report synthesis of Ag–SiO2 nanocomposite for the optical detection of Hg(II) ions as well as catalytic reduction of methylene blue (MB) dye. Ag–SiO2 nanocomposite was synthesized using a simple two step chemical route. The X-ray diffraction (XRD) pattern, UV–Visible absorbance spectra and X-ray photoelectron spectra (XPS) confirmed the successful synthesis of Ag–SiO2 nanocomposite. Transmission Electron Microscopy (TEM) images showed the decoration of Ag nanoparticles (NPs) of size ~9 nm on spherical ~155 nm sized SiO2 particles. The performance of as prepared nanocomposite towards optical detection of Hg(II) ions demonstrated the sensitive and selective detection by amalgam formation approach with the detection limit of 0.9 μM. Furthermore, the nanocomposite also showed superior catalytic activity towards MB reduction with pseudo first order kinetics rate constant 1.6 × 10−2 sec−1.