Behavior of Rotating Gold Microelectrodes

Baumann, Fred; Shain, Irving.

doi:10.1021/ac60122a039

Cited by 34 publications

(9 citation statements)

References 16 publications

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“…Little difference is observed upon directly scanning into the HER potential window from initial open‐circuit values, with neither electrode expressing significant HER activity. Redox reactions at Au surfaces may be hindered by adventitious adsorbed species, a problem that can be addressed by performing electrochemical conditioning or cycling of Au electrodes through positive potential ranges where Au oxides are formed . Considering that the Au nanoparticles used herein may retain adsorbed citrate or other impurities from the commercial sol source, we performed two electrochemical conditioning cycles between 0 and 1.2 V vs. Ag/AgCl in the same 0.1 M HClO 4 electrolyte.…”

Section: Resultssupporting

confidence: 89%

“…Redox reactions at Au surfaces may be hindered by adventitious adsorbed species, a problem that can be addressed by performing electrochemical conditioning or cycling of Au electrodes through positive potential ranges where Au oxides are formed. [86] Considering that the Au nanoparticles used herein may retain adsorbed citrate or other impurities from the commercial sol source, we performed two electrochemical conditioning cycles between 0 and 1.2 V vs. Ag/AgCl in the same 0.1 M HClO 4 electrolyte. Voltammetry of Au@pyC~S high in this region shows increased capacitive and oxidative current compared to pyC~S high , as well as a broad feature emerging at a potential characteristic of AuOx reduction (Figure 9b; x-axis converted to the NHE scale).…”

Section: Gold Nanoparticle-modified Pyc~s and Hydrogen Evolution At Amentioning

confidence: 99%

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Pyrolytic Carbon Films with Tunable Electronic Structure and Surface Functionality: A Planar Stand‐In for Electroanalysis of Energy‐Relevant Reactions

Parker

Sassin

et al. 2020

ChemElectroChem

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Fundamental charge‐transfer dynamics for technologically relevant carbons, such as disordered “hard” carbons, can be studied by designing planar mimics. We fabricate thin films of “pyrolytic carbon” (pyC) by decomposition of benzene at 1000 °C and examine the physical and electrochemical properties of the native pyC film, as well as variants after heteroatom doping, plasma oxidation, and metal nanoparticle modification. The pyC films are optically reflective at the macroscale, relatively planar (1–3 nm RMS roughness by atomic force microscopy) and disordered (via Raman scattering). Thiophenyl‐doped pyC films (0.6–1.7 atom % sulfur) suitably mimic the disorder, chemical state (X‐ray photoelectron spectroscopy), and work function (Kelvin probe) of a workhorse carbon black, Vulcan XC‐72. Using ferri/ferrocyanide as a redox probe, we find that oxygen functionalities enhance the heterogeneous electron‐transfer rate constant up to 3×, while high levels of sulfur dopants decrease the rate 2×. We also explore thiophenyl‐directed adsorption of Au nanoparticles and show that hydrogen evolution at 0.1 mA cm−2 occurs ∼95 mV more positive at <1 % Au@pyC∼S than at pyC∼S.

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Section: Resultssupporting

confidence: 89%

Section: Gold Nanoparticle-modified Pyc~s and Hydrogen Evolution At Amentioning

confidence: 99%

Pyrolytic Carbon Films with Tunable Electronic Structure and Surface Functionality: A Planar Stand‐In for Electroanalysis of Energy‐Relevant Reactions

Parker

Sassin

et al. 2020

ChemElectroChem

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“…Chromate has even been reported to thicken oxides on Pt. [52][53] The reasons why increases in net cathodic kinetics are observed after chromate treat- ment of Al compared to a decrease for Cu and Al 20 Cu 2 (MnFe) 3 also might lie in the relative contributions of the chromate reduction reaction to the net cathodic kinetics of these different metals. The rate of cathodic ORR kinetics on Al is much lower (2 to 3 orders of magnitude lower) than Cu and Al 20 Cu 2 (MnFe) 3 ( Figure 5).…”

Section: Apparent Vs Intrinsic Inhibition Of O 2 Reduction By Chromatementioning

confidence: 99%

Mass-Transport-Limited Oxygen Reduction Reaction on AA2024-T3 and Selected Intermetallic Compounds in Chromate-Containing Solutions

Ilevbare¹,

Scully²

2001

CORROSION

105

118

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Oxygen reduction reaction (ORR) kinetics were investigated on synthesized Al-Cu, Al-Cu-Mg, and Al-Cu-Fe-Mn intermetallic phases and compared toAA2024-T3 (UNS A92024), as well as high-purity Al, Cu, and Au. These tests were conducted in 0.1 M sodium sulfate (Na 2 SO 4 ) with and without either 0.005 M sodium chloride (NaCl, pH 6), 0.01 M sodium chromate (Na 2 CrO 4 , pH 8), or 0.0062 M Na 2 CrO 4 + 0.0038 M chromic acid (H 2 CrO 4 , pH 6) additions using stationary and rotating disk electrodes. Mass-transport-rate-controlled ORR were near theoretical values on all Cu-bearing materials and Au in 0.1 M Na 2 SO 4 with and without 0.005 M NaCl. Theoretical limiting current densities (CD) were not achieved in the mass-transport-controlled regime on Al because of the rate limitation of electron transfer through its oxide film. Four effects of chromate additions on such cathodic reaction rates were identified as follows: -Little intrinsic effect of chromate pretreatment on masstransport-controlled ORR on high-purity Cu, Cu-containing Al-based intermetallics, and Au electrodes in the absence of open-circuit corrosion. Charge transfer-controlled and mixedcontrolled ORR are lowered possibly by the blocking of O 2 adsorption sites by chromate anions. -Decreased net cathodic kinetics on AA2024-T3 as a function of the degree to which chromate suppressed open-circuit pitting corrosion prior to cathodic polarization. -Increased net cathodic kinetics on high-purity Al. -Decreased ORR kinetics on S-Al 2 CuMg as a result of minimization of Al(Mg) dissolution and, subsequently, minimization of the formation of a high, Cu-rich surface. Comments are made regarding the influence of each of these phenomena on open-circuit pitting of AA2024-T3.

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“…Baumann and Shain (14) found that rotating gold microelectrodes behave in many ways, similarly to platinum electrodes but display certain advan-tages such as resistance to oxidation in the absence of complexing anions.…”

Section: Densimetry Andmentioning

confidence: 99%

Automatic Operations

Patterson¹

1959

Anal. Chem.

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Behavior of Rotating Gold Microelectrodes

Cited by 34 publications

References 16 publications

Pyrolytic Carbon Films with Tunable Electronic Structure and Surface Functionality: A Planar Stand‐In for Electroanalysis of Energy‐Relevant Reactions

Pyrolytic Carbon Films with Tunable Electronic Structure and Surface Functionality: A Planar Stand‐In for Electroanalysis of Energy‐Relevant Reactions

Mass-Transport-Limited Oxygen Reduction Reaction on AA2024-T3 and Selected Intermetallic Compounds in Chromate-Containing Solutions

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