Electrodeposited gold nanoparticles on glassy carbon: Correlation between nanoparticles characteristics and oxygen reduction kinetics in neutral media

Abstract

International audienceGold nanoparticles (AuNPs) were deposited onto glassy carbon (GC) by constant potential electrolysis (CPE) using various sets of potential and duration from -0.3 to 0.7 V and 10 to 1800 s, respectively. The physico-chemical characteristics of the as-obtained deposits were investigated by cyclic voltammetry (CV) in H2SO4, field emission gun scanning electron microscopy (FEG-SEM), and Pb underpotential deposition (UPD). Their performances towards the oxygen reduction reaction (ORR) in a NaCl-NaHCO3 (0.15 M / 0.028 M, pH 7.4) neutral solution were examined and correlated to AuNPs size and density. The best results were obtained using the deposits which exhibited a high density (555 +/- 49 µm-2) of relatively small AuNPs (25 +/- 12 nm). The Koutecky-Levich treatment was systematically applied to all the deposits in order to determine the number of electrons n exchanged for the ORR in the potential range from 0.1 to -1 V. The values of the cathodic transfer coefficients Beta n were also extracted and compared to the values reported for unmodified GC and bulk Au. A map of the Beta n values as a function of AuNPs electrodeposition potential and duration was also provided

Evaluation of Microbial Fuel Cells with Graphite Plus MnO2and MoS2Paints as Oxygen Reduction Cathode Catalyst

“…Conventional platinum (Pt) and gold (Au) based catalysts have always been the best ORR catalysts as they exhibited a reduction of oxygen via a four-electron reduction pathway. 22,23 However, the high cost of platinum (Pt) catalysts and other precious metals used for ORR further rendered them as not suited for practical applications. 24 Furthermore, owing to its sensitivity to poisoning, the performance of a Pt based cathode may be substantially diminished in the presence of a variety of chemicals found in wastewater.…”

Sensitive Chronocoulometric Detection of miRNA at Screen-Printed Electrodes Modified by Gold-Decorated MoS2Nanosheets

“…The electrodeposited AuNPs are further characterized by performing CV experiments in a 0.5 M H2SO4 solution ( Figure S6b), 29 The Qox denotes the charges related to the reduction of Au-oxides, estimated by integrating the area under the corresponding reduction peak. [28][29] Au. In addition to those elements, the presence of C and O elements is evident, originating from the solvent and the atmosphere.…”

“…The electrodeposited AuNPs were further characterized by evaluating the charges related to the reduction of Au-oxides, abbreviated as Qox, by simply estimating the area under the corresponding reduction peak. 5,7 Redox activity of Fe(CN)6 3-/4at AuNPs@MoS2/SPGE. Figure S8).…”

“…In this contribution, we show that these requirements can be met under well controlled electrochemical deposition (ECD) conditions. 15,[26][27][28][29][30][31] ECD is also free of critical drawbacks such as the formation of "free" AuNPs, which usually coexist with AuNPs@MoS2 hybrids in solution-based routes. 11,22,24,[32][33] nanosheets (MoS2 NSs) on commercial screen-printed gold electrodes (SPGEs) (1); decoration of MoS2 NSs with AuNPs (to create AuNPs@MoS2 NSs) following an optimized chronoamperometric (CA) route (2); assembly of ssDNA capture probe: anti-miRNA-21 (CP), miRNA-21 target (TR) and signal amplification probe (AP) on AuNPs@MoS2/SPGE sensor (3)(4)(5); chronocoulometric (CC) detection of miRNA (TR) by monitoring [Ru(NH3)6] 3+ (RuHex) electrostatically bound to phosphate backbones of oligonucleotides (6).…”

Electrochemical Preparation and Characterization of a Gold Nanoparticles Graphite Electrode: Application to Myricetin Antioxidant Analysis

“…In the forward CV scan from 0.20 to 1.60 V, a large peak was observed in the region of 1.30 to 1.60 V. According to Yamamoto et al, this peak could likely be due to the formation of Au(III) hydroxide on the graphite surface,1 1,13,29,30 in the reverse CV scan from 1.60 to 0.20 V, a peak was observed at a potential of 0.87 V, which corresponded to stripping of the Au oxide. 29,30 By comparing the 1st with the 20th CV scans, a decrease in the peak current at the oxidation region was observed, which suggested a suppression of Au oxide formation on the graphite surface.…”