Tuning the direct growth of Agseeds into bimetallic Ag@Cu nanorods on surface functionalized electrochemically reduced graphene oxide: enhanced nitrite detection

Abstract

We describe a facile and an efficient method for the direct growth of bimetallic Ag@Cu nanorods (Ag@Cu NRDs) on electrochemically reduced graphene oxide (ERGO) nanosheets by a seed mediated growth approach. Surface functionalization of ERGO is a key step carried out using L-tryptophan that directs the growth of one dimensional Ag@Cu NRDs on its surface. The generated bimetallic Ag@Cu NRDs on L-tryptophan functionalized ERGO (Ag@Cu NRDs/L-ERGO) modified electrodes were characterised by SEM, XRD, EDAX, FT-IR and Raman spectroscopy. Anodic stripping voltammetry analysis and electrochemical impedance spectra were used to understand the electrochemical properties of the synthesized nanostructured material. The modified electrode enabled the electrooxidation of nitrite ions (NO₂⁻) with high sensitivity and a good detection limit of 1 nM. Importantly, the modified electrodes were successfully tested for the analyses of generated NO₂⁻ in urinary tract infection (UTI) affected patient's urine samples. In addition, the modified electrode was satisfactorily used in the electrooxidation of NO₂⁻ generated from in vitro biochemical reduction of nitrate ions using microbial species such as Escherichia coli (E. coli).