Silver Integrated with Carbonaceous 2D Nanomaterials as an Electrocatalyst for Reductive Dechlorination of Chloroacetanilide Herbicide

Abstract

In this work silver nanoparticles (AgNPs) were in situ synthesized on surface of graphene oxide (GO) and Ti3C2TX MXene at room temperature and without any reducing agent. The prepared GO_AgNPs and MX_AgNPs nanomaterials were deposited on electrodes and applied for voltammetric sensing of pesticide metazachlor. The chosen analyte underwent electrochemical reduction readable as faradaic current and identified as the electrochemical reductive dechlorination. It was found that GO_AgNP (electrochemically reduced to ErGO_AgNP before measurements) was more efficient catalyst of the observed dechlorination than MX_AgNP, even though it contained approximately 10-fold lower amount of silver. The smaller size of AgNP achieved with GO was the most probable reason. When the metazachlor sensing properties of the nanohybrid-modified electrodes were investigated, the linear range and the limit of detection of 37–1123 μM and 27 μM, respectively, were observed for ErGO_AgNP while only 37–375 μM and 40 μM for MX_AgNP. The ErGO_AgNP nanohybrid was more convenient also for metazachlor detection in alkali leachate of real soil samples, probably as the result of antifouling effect of ErGO. Although there are conventional instrumental analysis methods for sensing orders of magnitude lower concentrations of metazachlor, in this work it is for the first time shown that the AgNP-based nanohybrid efficiently catalyse the electrochemical dechlorination applicable for detection of this frequently used pesticide.