Synthesis of core/shell Au/Ag nanorods embedded in functionalized silicate sol-gel matrix and their applications in electrochemical sensors

A facile synthetic method was developed for the preparation of bimetal core/shell Au/Ag nanorods embedded in amine functionalized silicate so-gel matrix (Au-core/Ag-shell-TPDT NRs) in aqueous medium and its application toward the electrochemical detection of hydrogen peroxide (H2O2) and nitrite ions was demonstrated. The electrochemical characteristics of the Au-core/Ag-shell-TPDT NRs modified electrode were studied by cyclic voltammetry. The electrocatalysis and amperometric sensing of hydrogen peroxide and nitrite ions at physiological pH using the Au-core/Ag-shell-TPDT NRs modified electrode were investigated. The amperometric sensor showed enhanced electrocatalytic activity toward the detection of H2O2 and nitrite ions without the support of any mediator due to the synergetic catalytic effect of Au core and Ag shell. The amperometric current increased linearly with increasing the H2O2 concentration in the range from 100 nM to 1.2 mu M and the lowest detection limit was estimated using the standard procedure as 40 nM. The amperometric current increased linearly with increasing the nitrite ions concentration in the range from 100 nM to 1 mu M and the lowest detection limit was estimated using the standard procedure as 60 nM. The results of the study demonstrated that the GC/Au-core/Ag-shell-TPDT NRs modified electrode is simple to prepare that shows fast response, good stability and reproducible results and hence it is a promising material for the preparation of modified electrodes and electrochemical sensors. (C) 2012 Elsevier Ltd. All rights reserved.