Revisiting the factors influencing gold electrodes prepared using cyclic voltammetry

Xu, Xingxing; Makaraviciute, Asta; Pettersson, Jean; Zhang, Shi-Li; Nyholm, Leif; Zhang, Zhen

doi:10.1016/j.snb.2018.12.008

Cited by 34 publications

(29 citation statements)

References 39 publications

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“…12,14,[16][17][18][19][20] Dissolved Pt ions can reach and become deposited on the electrocatalyst surface, increasing the apparent activity of the test material. 3,7,8,12,[21][22][23][24][25][26] Increasing the surface area of the counter electrode decreases the current density it experiences, and while this can slow the dissolution process, it cannot stop it. 27 Dissolved Clions (either from the supporting electrolyte or leaking from a reference electrode) can also increase the rate of dissolution of Pt and Au electrodes through the formation of metal-chloride complexes.…”

Section: Introductionmentioning

confidence: 99%

“…27 Dissolved Clions (either from the supporting electrolyte or leaking from a reference electrode) can also increase the rate of dissolution of Pt and Au electrodes through the formation of metal-chloride complexes. 12,25 One of the most common strategies for mitigating the effects of dissolution of Pt counter electrodes is to separate the test electrocatalyst from the counter electrode using a Nafion membrane. 12,22,[27][28][29] However, a search of the literature does not reveal strong evidence for the effectiveness of this strategy.…”

Section: Introductionmentioning

confidence: 99%

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Best Practice for Evaluating Electrocatalysts for Hydrogen Economy

Bird

Goodwin

Walsh

2020

ACS Appl. Mater. Interfaces

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Screening new electrocatalysts is key to the development of new materials for next-generation energy devices such as fuel cells and electrolysers. The counter electrodes used in such tests are often made from materials such as Pt and Au, which can dissolve during testing and deposit onto test electrocatalysts, resulting in inaccurate results. The most common strategy for preventing this effect is to separate the counter electrode from the test material using an ion-transporting Nafion membrane. Here, we use X-ray photoelectron spectroscopy, energy-dispersive X-ray analysis, mass spectrometry, and voltammetry to demonstrate the limitations of this approach during constant-current, extended stability testing of electrocatalysts for H2 evolution. We show that Nafion membranes cannot prevent contamination of carbon electrocatalysts by Pt and Au counter electrodes, leading to an apparent increase in electrocatalytic activity of the carbon. We then demonstrate that carbon counter electrodes in undivided cells can contaminate and deactivate Pt and Au electrocatalysts for H2 evolution. We show that use of a setup comprising a glass frit separating a carbon counter electrode from the test electrocatalyst can prevent these effects. Finally, we discuss these phenomena using H2 evolution at MoS2 and at a K6[P2W18O62](H2O)14/carbon nanotube composite as test reactions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Best Practice for Evaluating Electrocatalysts for Hydrogen Economy

Bird

Goodwin

Walsh

2020

ACS Appl. Mater. Interfaces

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“…[20] Classical voltammetric behaviors of polycrystalline Au electrode in H 2 SO 4 were observed (Figure 1b) denoting a clean and homogenous Au surface, where the Faradaic currents of water-dissociation adsorption (anodic scan) and the oxygenadspecies desorption (cathodic scan) were well-defined as those obtained on macro-and micro-electrodes. [21] Figures 2a-c report a series of cyclic voltammograms recorded for UPD of Pb on polycrystalline Au at three different Au nanodisk electrodes at a series of scan rates increasing from 0.1 V s À 1 to 1 V s À 1 in steps of 0.1 V s À 1 . The inserts are the steady-state voltammograms of each nanoelectrode obtained with the same experimental conditions as described in Figure 1a, which are employed to determine the apparent diameter of each nanoelectrodes.…”

Section: Resultsmentioning

confidence: 99%

Surface Diffusion of Underpotential‐Deposited Lead Adatoms on Gold Nanoelectrodes

et al. 2021

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Dedicated to honor the memory of Prof. Jean-Michel Savéant and to acknowledge his legacy to electrochemical sciences.A simple and readily applicable voltammetric approach is described to characterize and measure the site-hopping surface diffusion of underpotential-deposited (UPD) metal adatoms at nanoelectrodes. UPD refers to the deposition of atoms on foreign metal supports at potentials lower than those predicted by Nernst law for a bulk deposition. Despite its importance in several fields of catalysis, advanced nanofabrication or even atomic nanoengineering by atomic layer epitaxy, diffusion of UPD adatoms is difficult to observe at micro-and macroelectrodes. In fact, at electrodes of usual dimensions, UPD adatoms surface diffusion is masked by other electrochemical phenomena of greater relative amplitudes. Conversely, at nanowires electrodes sealed in glass, only an extremely small fraction of the surface of the wires is exposed to the electrolyte solution and is rapidly loaded. This allows the spillage of UPD adatoms onto the much larger area of the nanowire rod which is immune to Faradaic reactions due to its isolation from the electrochemical solution by the glass casing. Therefore, surprisingly for a UPD process, voltammetric peaks currents and integral desorption charges primarily reflect these diffusional surface processes so that the integral charges vary linearly with the inverse of the square root of the scan rate. This is easily observable and measurable with usual bench-level electrochemical instrumentation. In this work, by using nanoelectrodes with diameters between 90 and 260 nm, we were able to establish the major involvement of this site-hopping surface diffusion of UPD Pb adatoms on polycrystalline gold (Au) and characterize it quantitatively. The equivalent surface diffusion coefficient of UPD Pb adatoms was determined to be~4.4 × 10 À 11 cm 2 s À 1 at room temperature, corresponding to a Gibbs free energy activation barrier of ca. 18.72 kJ mol À 1 (i. e., 0.19 eV per Pb adatom) for the reaction of inter-sites exchange of Pb adatoms on a polycrystalline Au surface.

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“…Cyclic voltammetry of an unmodified gold electrode in PBS mainly passed current through capacitance (Figure 2). A very small oxidation peak at 270 mV is associated with oxide formation and a reduction current below -250 mV is due to oxide and residual oxygen reduction 51 . After modifying the electrode with PEDOT-XRU84, the cyclic voltammetry became featureless over the potential window of 0.8 to -0.8 V. This indicates the gold surface oxide formation and reduction processes, and oxygen reduction is prevented or significantly reduced in relative magnitude to the redox response of the conducting polymer after surface modification.…”

Section: B Electrochemical Characterisationmentioning

confidence: 99%

Fibrinogen, collagen, and transferrin adsorption to poly(3,4-ethylenedioxythiophene)-xylorhamno-uronic glycan composite conducting polymer biomaterials for wound healing applications

et al. 2021

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We present the conducting polymer poly (3,4-ethylenedioxythiophene) (PEDOT) doped with an algal-derived glycan extract, Phycotrix™ [xylorhamno-uronic glycan (XRU84)], as an innovative electrically conductive material capable of providing beneficial biological and electrical cues for the promotion of favorable wound healing processes. Increased loading of the algal XRU84 into PEDOT resulted in a reduced surface nanoroughness and interfacial surface area and an increased static water contact angle. PEDOT-XRU84 films demonstrated good electrical stability and charge storage capacity and a reduced impedance relative to the control gold electrode. A quartz crystal microbalance with dissipation monitoring study of protein adsorption (transferrin, fibrinogen, and collagen) showed that collagen adsorption increased significantly with increased XRU84 loading, while transferrin adsorption was significantly reduced. The viscoelastic properties of adsorbed protein, characterized using the ΔD/Δf ratio, showed that for transferrin and fibrinogen, a rigid, dehydrated layer was formed at low XRU84 loadings. Cell studies using human dermal fibroblasts demonstrated excellent cell viability, with fluorescent staining of the cell cytoskeleton illustrating all polymers to present excellent cell adhesion and spreading after 24 h.

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Revisiting the factors influencing gold electrodes prepared using cyclic voltammetry

Cited by 34 publications

References 39 publications

Best Practice for Evaluating Electrocatalysts for Hydrogen Economy

Best Practice for Evaluating Electrocatalysts for Hydrogen Economy

Surface Diffusion of Underpotential‐Deposited Lead Adatoms on Gold Nanoelectrodes

Fibrinogen, collagen, and transferrin adsorption to poly(3,4-ethylenedioxythiophene)-xylorhamno-uronic glycan composite conducting polymer biomaterials for wound healing applications

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