Ag-Cu nanoalloys: An electrochemical sensor for H2O2 detection

Nanoalloys (Ag-Cu)-based electrochemical sensor for H2O2 detection has been fabricated. Pure silver (Ag) nanoparticles (NPs) and silver-copper (Ag-Cu) nanoalloys have been synthesized by using chemical reduction methodology while ratios of precursors vary as 9:1, 8:2, 7:3 and 6:4. Characterization of the prepared samples has been carried out by X-ray diffraction (XRD) which revealed the face centered cubic crystal structure of Ag NPs and Ag-Cu nanoalloys. An average crystallite size of powdered samples was calculated from XRD analysis to be 20–50 nm. Scanning electron microscopy exhibits spherical distribution of nanoparticles of the prepared alloys. A red shift was measured using UV–visible spectroscopy corresponding to the increase of copper contents in Ag-Cu nanoalloys. Cyclic voltammetric (CV) response of nanoalloys modified glassy carbon electrode was recorded in phosphate buffer of pH 7.4 in the absence and presence of H2O2. CV results demonstrate reduction of H2O2 at 0 V. Charge transfer resistance (Rct) has been calculated from electrochemical impedance spectroscopy and is considered as sensing parameter in the present study. Among all the compositions, Ag-Cu (9:1) nanoalloys have shown the best sensing performance towards detection of H2O2 having limit of detection (LOD) and limit of quantification (LOQ) of 152 µM and 508 µM, respectively.