Silicate sol–gel stabilized silver nanoparticles for sensor applications toward mercuric ions, hydrogen peroxide and nitrobenzene

Abstract

Here, we developed a silver nanoparticles (Ag NPs) based sensor for the detection of mercuric ions (Hg(II)), hydrogen peroxide (H2O2) and nitrobenzene. The silicate sol–gel (SSG) stabilized Ag NPs were synthesized via one-pot synthetic route using the mixture of hydrazine, ammonium chloride and nitric acid as reduction solution. The Ag NPs were further characterized by absorption spectra, XRD, SEM, TEM, EDX and SAED analyses. The spectral and colorimetric methods revealed the efficiency of Ag NPs to detect Hg(II) ions and the lowest detection limit was found to be 5μM. Also, Ag NPs exhibited selectivity toward Hg(II) ions in the presence of other environmentally relevant heavy metal ions. For the detection of H2O2, an enzymeless electrochemical sensor was prepared by modifying glassy carbon electrode with SSG stabilized Ag NPs. Using the linear sweep voltammetry (LSV) and differential pulse voltammetry (DPV) techniques, the lowest experimental detection limits for H2O2 sensing were found to be 0.5 and 0.1μM, respectively. Similarly, the electrochemical sensing of nitrobenzene using the modified electrode was identified to have the lowest experimental detection limit of 1μM by square wave voltammetry (SWV).