Gold-Silver Bimetallic Alloy Nanoparticles in a Covalent Organic Framework for Real-Time Monitoring of Hydrogen Peroxide from Live Cells

Abstract

An efficient and simple way has been described to prepare gold and silver bimetallic alloy nanoparticles (Au-AgNPs) in an organic framework with a metal-free core. The growth of alloy Au-AgNPs was monitored by UV-visible spectroscopy (UV-vis) and confirmed using various spectral, microscopy, and electrochemical techniques. The field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) results revealed that the covalent organic framework (COF) had a uniform flake-like morphology, and the alloy-based Au-AgNPs had a flower-like structure. The results of X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) indicated that Au-AgNPs are metallic in nature and highly crystalline. The surface of a glassy carbon electrode (GCE) was then modified with Au-AgNPs-COF, which was subsequently employed for enzyme-free electrochemical reduction of H2O2. The electrocatalytic cyclic voltammetry performance of the different modified electrodes was in the following order: COF (-14.82 μA) < AgNPs-COF (-26.95 μA) < AuNPs-COF (-31.78 μA)