Electrochemical reversibility of reticulated vitreous carbon electrodes heat treated at different carbonization temperatures

Gonçalves, Emerson Sarmento; Rezende, Mirabel Cerqueira; Takahashi, Marta Ferreira Koyama; Ferreira, N.G.

doi:10.1590/s1516-14392006000200007

Cited by 13 publications

(3 citation statements)

References 28 publications

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“…Therefore, during diamond growth the substrate releases these volatiles and a portion of them precipitates forming the bubbles. These bubble formations were also observed in the literature at low substrate HTT [28]. The presence of boron crystals was confirmed by energy dispersive x-ray spectroscopy (EDS) of the circled area presented in figure S2(a), which refers to B-UNCD/RVC7-1000 sample.…”

Section: Morphological Analysessupporting

confidence: 83%

Influence of modified carbon substrate on boron doped ultrananocrystalline diamond deposition

Oishi

Silva

Botelho

et al. 2018

Mater. Res. Express

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Boron doped ultrananocrystalline diamond (B-UNCD) growth was studied on modified reticulated vitreous carbon (RVC) produced from poly(furfuryl alcohol) (PFA) resin with sodium hydroxide additions at two different heat treatment temperatures. The different amounts of NaOH in PFA (up to reaching pH values of around 3, 5, 7, and 9) aimed to neutralize the acid catalyst and to increase the PFA storage life. Besides, this procedure was responsible for increasing the oxygen content of RVC samples. Thus, the effect of carbon and oxygen coming from the substrates in addition to their different graphitization indexes on diamond morphology, grain size, preferential growth and boron doping level were investigated by FEG-SEM, x-ray diffraction and Raman spectroscopy. Therefore, B-UNCD films were successfully grown on RVC with pH values of 3, 5, 7, and 9 heat treated at 1000 and 1700°C. Nonetheless, the higher oxygen amount during B-UNCD growth for samples with pH 7 and 9 heat treated at 1000°C was responsible for the RVC surface etching and the decrease in the boron concentration of such samples. The cross section images showed that B-UNCD infiltrated at around 0.9 mm in depth of RVC samples while carbon nanowalls were observed mainly on RVC samples heat treated at 1000°C for all pH range studied.

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Section: Morphological Analysessupporting

confidence: 83%

Influence of modified carbon substrate on boron doped ultrananocrystalline diamond deposition

Oishi

Silva

Botelho

et al. 2018

Mater. Res. Express

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“…The carbon acts as a protective layer to prevent photocorrosion of ZnTe by blocking the free access of electrolyte and providing a bridge for the photogenerated electron transfer from ZnTe into the electrolyte with its good conductivity and suitable electronic energy level estimated from its work function (4.00–4.81 eV). − Thus, carbon-coated ZnTe improved both PEC activity and stability of the photocathode. Meanwhile, MoS 2 of a p-type property as confirmed by Mott–Schottky plot has a straddling band alignment with ZnTe suitable for heterojunction formation as shown in the energy configuration of Figure S11d.…”

Section: Resultsmentioning

confidence: 99%

Solar Hydrogen Production from Zinc Telluride Photocathode Modified with Carbon and Molybdenum Sulfide

Jang

Lee

et al. 2016

ACS Appl. Mater. Interfaces

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A zinc telluride (ZnTe) film modified with MoS2 and carbon has been studied as a new photocathode for solar hydrogen production from photoelectrochemical (PEC) water splitting. The modification enhances PEC activity and stability of the photocathode. Thus, the MoS2/C/ZnTe/ZnO electrode exhibits highly improved activity of -1.48 mA cm(-2) at 0 VRHE with a positively shifted onset potential up to 0.3 VRHE relative to bare ZnO/ZnTe electrode (-0.19 mA cm(-2), 0.18 VRHE) under the simulated 1 sun illumination. This represents the highest value ever reported for ZnTe-based electrodes in PEC water splitting. The carbon densely covers the surface of ZnTe to protect it against photocorrosion in aqueous electrolyte and improves charge separation. In addition, MoS2 further enhances the PEC performance as a hydrogen evolution co-catalyst.

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“…It is well known that for this system the kinetic parameters reported are highly variable even when using apparently identical electrodes and conditions (see [2][3][4][5][6][7][8][9][10][11][12][13][14] and references cited therein). Using our new approach we are able to show that this difficulty is not due to the impact of random experimental noise, since for each individual data set we are able to fit the mathematical model to the experimental data extremely accurately.…”

Section: Introductionmentioning

confidence: 99%

Separating the Effects of Experimental Noise from Inherent System Variability in Voltammetry: The [Fe(CN)₆]^3–/4– Process

et al. 2018

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Recently, we have introduced the use of techniques drawn from Bayesian statistics to recover kinetic and thermodynamic parameters from voltammetric data, and were able to show that the technique of large amplitude ac voltammetry yielded significantly more accurate parameter values than the equivalent dc approach. In this paper we build on this work to show that this approach allows us, for the first time, to separate the effects of random experimental noise and inherent system variability in voltammetric experiments. We analyse ten repeated experimental data sets for the [Fe(CN) 6 ] 3−/4− process, again using large-amplitude ac cyclic voltammetry. In each of the ten cases we are able to obtain an extremely good fit to the experimental data and obtain very narrow distributions of the recovered parameters governing both the faradaic (the reversible formal faradaic potential, E 0 , the standard heterogeneous charge transfer rate 1 arXiv:1810.02187v1 [eess.SP] 18 Sep 2018 constant k 0 , and the charge transfer coefficient α) and non-faradaic terms (uncompensated resistance, R u , and double layer capacitance, C dl ). We then employ hierarchical Bayesian methods to recover the underlying "hyperdistribution" of the faradaic and non-faradaic parameters, showing that in general the variation between the experimental data sets is significantly greater than suggested by individual experiments, except for α where the inter-experiment variation was relatively minor. Correlations between pairs of parameters are provided, and for example, reveal a weak link between k 0 and C dl (surface activity of a glassy carbon electrode surface). Finally, we discuss the implications of our findings for voltammetric experiments more generally.

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Electrochemical reversibility of reticulated vitreous carbon electrodes heat treated at different carbonization temperatures

Cited by 13 publications

References 28 publications

Influence of modified carbon substrate on boron doped ultrananocrystalline diamond deposition

Influence of modified carbon substrate on boron doped ultrananocrystalline diamond deposition

Solar Hydrogen Production from Zinc Telluride Photocathode Modified with Carbon and Molybdenum Sulfide

Separating the Effects of Experimental Noise from Inherent System Variability in Voltammetry: The [Fe(CN)₆]^3–/4– Process

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Electrochemical reversibility of reticulated vitreous carbon electrodes heat treated at different carbonization temperatures

Cited by 13 publications

References 28 publications

Influence of modified carbon substrate on boron doped ultrananocrystalline diamond deposition

Influence of modified carbon substrate on boron doped ultrananocrystalline diamond deposition

Solar Hydrogen Production from Zinc Telluride Photocathode Modified with Carbon and Molybdenum Sulfide

Separating the Effects of Experimental Noise from Inherent System Variability in Voltammetry: The [Fe(CN)6]3–/4– Process

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Separating the Effects of Experimental Noise from Inherent System Variability in Voltammetry: The [Fe(CN)₆]^3–/4– Process