Electrochemical synthesis of silver nanoparticles-coated gold nanoporous film electrode and its application to amperometric detection for trace Cr(VI)

Abstract

A simple and rapid approach for the electrochemical synthesis of Ag nanoparticles-coated gold nanoporous film (AgGNF) on a gold substrate was reported. The solid gold electrode (SGE) was directly anodized under a high potential of 5 V, and then reduced to obtain gold nanoporous film (AuNF) by freshly prepared ascorbic acid. The Ag nanoparticles (AgNPs) were grown on the AuNF electrode by potential-step electrodeposition. The resulting AgGNF composites electrodes were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy and cyclic voltammetry (CV). As-prepared AgGNF electrode was used as a kind of superior sensor for Cr(VI) detection, which exhibited better electrocatalytic behavior than those of AuNF and SGE under identical conditions. Such a designed AgGNF nanocomposites electrode showed outstanding sensitivity (about 0.15 nA/ppb) and favorable reproducibility for Cr(VI) detection. The dependence of reduction current on Cr(VI) concentration is linear from 2 to 370 ppb with a low detection limit of 0.65 ppb. Interferences from other heavy metals ions (Cr 3+ , Cu 2+ , Pb 2+ , As 3+ and Hg 2+ ) associated with Cr(VI) analysis could be effectively diminished. The present method proves to be rapid, reliable, sensitive and low-cost.

Preparation, Modification, Characterization, and Biosensing Application of Nanoporous Gold Using Electrochemical Techniques

“…One of the recent works involves the immobilization of fructose dehydrogenase on a np-Au surface for sensitive and selective detection of d -fructose using chronoamperometry ( Figure 7 ) [ 140 ]. The enzyme fructose dehydrogenase orients on np-Au surface exposing its FAD and heme subunits.…”

“…Conditions: applied potential of 0.15 V. Reproduced with permission from ref. [ 140 ], Copyright 2017, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.…”

Structure and Applications of Gold in Nanoporous Form

“…On the other hand, the pore size created by directly holding the potential for 20 V or 40 V in the same electrolyte solution for similar time was found to create the smaller pore sizes. Xu and co-workers anodized the cleaned gold wire using potential of 5 V for 180 s in 0.15 M phosphate buffer to form oxides on electrode surface (evident by salmon pink color of the electrode surface) followed by reduction of gold oxide by 1 M ascorbic acid solution at room temperature to prepare np-Au (evident by change in color of the electrode surface to black) [42].…”

Comparison between Modified and Unmodified Carbon Paste Electrodes for Hexavalent Chromium Determination

“…Due to the toxicity problems associated to mercury, a huge number of other kind of modified electrodes have been applied, such as bismuth film‐wrapped single‐walled carbon nanotubes‐modified glassy carbon electrode (Bi/SWCNTs/GCE) . Recent works have been focused on gold electrodes or on electrodes modified by gold nanoparticles (AuNPs), such as AuNPs‐indium tin oxide (ITO) , AuNPs‐modified screen‐printed electrode (SPE) , AuNPs‐modified carbon screen‐printed electrode (AuNPs‐CSPE) , AgNPs‐coated gold nanoporous film (AgNPs‐GNF) on a gold substrate , gold nanoelectrode ensemble using two AuNPs layers; the first is electroplated for binding 3‐mercaptopropyltrimethoxysilane (MPTS) while The second AuNPs layer is then self‐assembled on the surface of the MPTS, forming flower‐like gold nanoelectrodes, then functionalized by a thiol pyridinium PET/AuNPs/MPTS/AuNPs/GCE . Previous papers reported in literature did not investigate interference of chloride .…”