Potential Sensing Platform of Silver Nanoparticles Embedded in Functionalized Silicate Shell for Nitroaromatic Compounds

A simple and new method to grow a pentagonally twinned structure of silver-silicate core−shell nanoparticles in aqueous environment at room temperature and its application in nitrobenzene (NB) sensing is described here. Silver-silicate core−shell nanoparticles were obtained by one-step synthesis using N-[3-(trimethoxysilyl)propyl]-ethylene diamine (EDAS) as a reducing/stabilizing agent and cetyltrimethylammonium bromide (CTAB) as the growing agent for the growth of silver nanoparticles (Ag_nps). The silver-silicate core−shell nanoparticles were characterized by high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), scanning electron microscope (SEM), UV−visible absorption, emission, excitation, and electrochemical measurements. The electrochemical studies of silver-silicate core−shell nanoparticles modified electrode showed the silver nanoparticle’s oxidation potential and their corresponding reduction potential at 0.24 and −0.16 V, respectively. The optical and electrochemical applications silicate-shell stabilized silver nanoparticles were established toward nitrobenzene. The optical sensing of nitrobenzene by silver-silicate core−shell nanoparticles studied using absorption and emission spectral methods showed experimentally determined lowest detection limits (LOD) of 1 and 10 μM, respectively. Silver-silicate core−shell nanoparticles showed excellent electrocatalytic activity toward the reduction of nitrobenzene. The electrochemical sensor showed the lowest detection limit (LOD) of 2.5 nM toward nitrobenzene sensing.