13 research outputs found
Fabrication of dendritic nanoporous gold via a two-step amperometric approach: Application for electrochemical detection of methyl parathion in river water samples
No full textIn this work, nanoporous gold (NPG) was prepared according to three different approaches, such as (i) anodization-electrochemical reduction (A-ECR, NPGA), (ii) dynamic hydrogen bubble template (DHBT, NPGB), and (iii) the combination of both methods (NPGA+B). Field-emission scanning electron microscopy (FE-SEM) and cyclic voltammetry (CV) were used to investigate the structural morphology and the electrochemical behavior of the fabricated materials. The NPGA+B electrode showed a large amount of surface defects and/or edges, greater electrochemical surface area (2.5 cm2), and increased roughness factor (35.4). Such outstanding features of the NPGA+B platform were demonstrated by the sensitive detection of methyl parathion (MP) in river water samples. CV results indicated nearly 25-fold, 6-fold, and 2.5-fold higher sensitivity for NPGA+B compared to that of bare Au, NPGA, and NPGB, respectively. Differential pulse voltammetry (DPV) results show a linear behavior in the MP concentration range of 5–50 ng mL−1 with a limit of detection (LOD) of 0.6 ng mL−1 and limit of quantification (LOQ) of 2.0 ng mL−1. Besides, the NPGA+B sensor also revealed excellent selectivity towards MP detection in the presence of other interfering molecules or ions, reproducibility, and repeatability.Fil: Silva Junior, Gilberto J.. Universidade de Sao Paulo; BrasilFil: Selva, Jéssica Soares Guimarães. Universidade de Sao Paulo; BrasilFil: Sukeri, Anandhakumar. Universidade de Sao Paulo; BrasilFil: Gonçalves, Josué Martins. Universidade de Sao Paulo; BrasilFil: Regiart, Daniel Matias Gaston. Universidade de Sao Paulo; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; ArgentinaFil: Bertotti, Mauro. Universidade de Sao Paulo; Brasi
Nanoporous Gold Surface: An Efficient Platform for Hydrogen Evolution Reaction at Very Low Overpotential
No full textElectrodeposited honeycomb-like dendritic porous gold surface: An efficient platform for enzyme-free hydrogen peroxide sensor at low overpotential
No full textDevelopment of non-enzymatic and highly selective hydrogen peroxide sensor based on nanoporous gold prepared by a simple unusual electrochemical approach
No full textNanoporous Gold Surface: An Efficient Platform for Hydrogen Evolution Reaction at Very Low Overpotential
No full textA nanostructured porous gold film (NPGF) was fabricated onto a gold electrode surface by an electrochemical approach involving anodization followed by electrochemical reduction in absence of binary alloys, templates and chemical reducing agents. The electrocatalytic activity of the as-fabricated electrocatalyst was examined towards hydrogen evolution reaction (HER) and very low onset potential (−0.048 V) and overpotential values of −0.070 and −0.083 V at current densities of 10 and 20 mA cm -2, respectively, were obtained in 0.5 mol L -1 sulfuric acid solution, along with exchange current density (jo) of 0.126 mA cm -2. A small Tafel slope of ca. 36 mV decade -1 was achieved, indicating the HER takes place according to a Volmer-Heyrovsky mechanism and that the electrochemical desorption of hydrogen is the rate determining step. The performance of the NPGF electrode was compared with that of bulk gold and platinum electrodes, and a platinum-like behavior was noticed for HER. Finally, the durability of the proposed electrocatalyst was examined using voltammetric and amperometric techniques and an excellent stability was achieved.</div
Electrocatalytic oxidation of NADH at low overpotential using nanoporous poly(3,4)-ethylenedioxythiophene modified glassy carbon electrode
No full textA novel approach for one-step fabrication of platinum-nanoporous gold film via oxygen bubble template with enhanced electrochemical activity
No full textA simple method was proposed to deposit a platinum-nanoporous gold film (Pt-NPGF) on a Au surface in absence of binary alloys, chemical reducing agents, and stabilizers using the in-situ generated oxygen bubble template approach. FE-SEM, EDX, and cyclic voltammetry were used for microscopic analysis and electrochemical studies. The small amount of Pt particles presented over the NPGF substantially improved the electrocatalytic activity e.g. for methanol oxidation, as an enhanced current response with low CO poisoning was observed at the Pt-NPGF electrode compared to that of bare Au, Pt, and NPGF electrodes in alkaline solution. Moreover, diffusion-limiting plateau currents corresponding to both H2O2 oxidation and reduction processes were noticed in PBS solution at a Pt-NPGF microelectrode. Keywords: Pt-NPGF, Oxygen bubble template, Electrocatalytic activity, Methanol, Hydrogen peroxid
Simultaneous Determination of Cadmium and Lead Using PEDOT/PSS Modified Glassy Carbon Electrode
No full textA facile electrochemical approach to fabricate a nanoporous gold film electrode and its electrocatalytic activity towards dissolved oxygen reduction
No full textNanoporous Gold Microelectrode: A Novel Sensing Platform for Highly Sensitive and Selective Determination of Arsenic (III) using Anodic Stripping Voltammetry
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