Silver nanoparticles embedded in cyclodextrin–silicate composite and their applications in Hg(ii) ion and nitrobenzene sensing

Different synthetic routes were described to prepare silver (Ag) nanoparticles (NPs) embedded in an amine functionalized silicate sol–gel matrix (TPDT) by employing different combination of reagents such as silicate sol–gel (TPDT), β-cyclodextrin (CD)–TPDT, TPDT–surfactant (BDAC), CD–TPDT–BDAC and CD–TPDT–BDAC/ascorbic acid (AA). The spectral and colorimetric detection of Hg(II) ions were carried out using the Ag NPs which showed a significant blue shift in the surface plasmon resonance (SPR) band upon the addition of Hg(II) ions. It was found that the addition of optimum level of Hg(II) ions into the Ag NPs completely quenched the SPR band and deformed the shape of the Ag NPs due to the formation of anisotropic Ag amalgam crystals (AgHg). The selective detection of Hg(II) ions using the Ag NPs in the presence of other environmentally relevant metal ions by spectral and colorimetric methods was also reported. Furthermore, the prepared Ag nanostructure modified electrodes were employed for the electrocatalytic reduction and sensing of nitrobenzene.