Bimetallic Au/Ag nanorods embedded in functionalized silicate sol-gel matrix as an efficient catalyst for nitrobenzene reduction

A simple method for the preparation of bimetallic gold/silver nanorods embedded in amine functionalized silicate sol-gel matrix (Au/Ag-TPDT NRs) in aqueous medium and their application towards the catalytic reduction of nitrobenzene is reported. The Au/Ag-TPDT NRs are prepared by using N-1-[3-trimethoxysilyl)propyl]diethylene triamine (TPDT) as a reducing as well as stabilizing agent. The catalytic activity of the Au/Ag-TPDT NRs is evaluated by studying the catalytic reduction of nitrobenzene to aniline upon the addition of NaBH4 in an aqueous solution. The Au/Ag-TPDT NRs was found to be a good catalyst when compared to the Au-TPDT NRs and Au NRs for the reduction of nitrobenzene to aniline at room temperature. The enhanced catalytic activity of Au/Ag-TPDT NRs is due to the synergistic effect of Au and Ag present in the bimetallic Au/Ag-TPDT NRs. The reaction rate constants (k) are estimated to be 0.4050, 0.2515 and 0.1235 min(-1) for Au/Ag-TPDT NRs, Au-TPDT NRs and Au NRs, respectively. The electrocatalytic reduction of nitrobenzene at pH 7 using the Au/Ag-TPDT NRs modified electrode is also investigated and compared with the Au-TPDT NRs. The higher electrocatalytic activity of Au/Ag-TPDT NRs is due to the synergistic effect of Au and Ag present in the bimetallic Au/Ag-TPDT NRs. The results of the study demonstrate that the Au/Ag-TPDT NRs are efficient catalyst for the catalytic reduction of nitrobenzene. (C) 2013 Elsevier B.V. All rights reserved.