Electrochemical behavior of exfoliated NiCl2–graphite intercalation compound affected by hydrogen sorption

Skowroński, J. M.; Krawczyk, Piotr; Rozmanowski, Tomasz; Urbaniak, J.

doi:10.1016/j.enconman.2008.02.027

Cited by 22 publications

(13 citation statements)

References 40 publications

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“…Such a behavior indicates that during the second and third cycle the regarded cathodic peaks are likely associated with reduction of Pd oxides formed on the surface of electrode during the previously performed anodic oxidation [15,19]. For the first cycle, during the anodic polarization, presented curve involves anodic wave with two maxima positioned at − 0.602 and − 0.49 V. These effects can be assigned to oxidation of Ni particles [7,15,[22][23][24][25]30]. During the second and third cycle the location of these peaks vary due to activation of Ni.…”

Section: Electrochemical Investigations Of Eg/ni/pd Composite In Elecmentioning

confidence: 88%

“…High stability with simultaneous high electrochemical activity are provided by application of graphite intercalation compounds (GIC). They are prepared by insertion of ions and/or molecules, e.g., alkali metals, metal oxides or transition metal chlorides between the interlayer space of graphite structure [22][23][24][25]. Chemical vapor deposition (CVD) may be considered as an alternative way for synthesis of metal-carbon composites [26,27].…”

Section: Introductionmentioning

confidence: 99%

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Methanol Electrooxidation at Electrodes Made of Exfoliated Graphite/Nickel/Palladium Composite

2019

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This paper try to answer the question, if the exfoliated graphite/nickel/palladium (EG/Ni/Pd) composite can be regarded as a potential anode material in direct methanol fuel cells (DMFCs). For this purpose, process of electrochemical oxidation of methanol on electrode made of EG/Ni/Pd was investigated. Electrochemical investigations were conducted in alkaline medium by cyclic voltammetry and potentiostatic techniques. Informations on catalytic activity of the examined composite were acquired from the comparison of current charges calculated for methanol oxidation peaks. The investigations revealed that electrochemical activity of EG/Ni/Pd composite enhances along the potential cycling. Current charges of methanol oxidation peaks increase with number of conducted cycles up to 26th cycle. The increment in electrochemical activity impacts on the decline in methanol concentration in the investigated electrolyte. The results of electrochemical investigations for EG/ Ni/Pd composite were compared to that acquired for EG/Pd. The difference in total organic carbon (TOC) before and after the selected cycles of electrochemical process at EG/Ni/Pd electrode were the source of information on degree of methanol oxidation. Process comprised of 50 cycles of methanol electrooxidation resulted over 50% decrease in its concentration. The interpretation of electrochemical investigations were supported by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray photoelectron spectroscopy (XPS) analysis.

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Section: Electrochemical Investigations Of Eg/ni/pd Composite In Elecmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Methanol Electrooxidation at Electrodes Made of Exfoliated Graphite/Nickel/Palladium Composite

2019

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“…The tightness of Pd layer coating a Ni support was checked by recording CV curves in the potential range −1.1↔0.55 V (not shown here). As shown in our previous papers reporting on nickel foam electrode [34,35], the limit value of 0.55 V in 6 M KOH solution is high enough to record the anodic peak associated with the Ni(OH) 2 → NiOOH transformation. The lack of the peak at about 0.4 V on CV curves for Ni/Pd electrode proves the Pd layer to be impermeable to electrolyte to reach a Ni sublayer.…”

Section: Resultsmentioning

confidence: 97%

Relationship between the reactions of hydrogen sorption/desorption and methanol oxidation on bifunctional Ni/Pd electrode in alkaline solution

Skowroński

Rozmanowski

2012

J Solid State Electrochem

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The present paper is aimed at studying the influence of the hydrogen sorption/desorption process occurring on the layered nickel-palladium (Ni/Pd) electrode on the kinetics of the reaction of methanol oxidation in strong alkaline KOH solution. The electrodes were prepared by chemical deposition of a thin layer of porous palladium on a nickel foam support. A scanning electron microscope was used for studying the morphology of both the nickel support and the porous palladium layer. The mechanism of the anodic desorption of hydrogen changes depending on whether or not 6 M KOH electrolyte is admixed with methanol. It was shown that, in the first cycle of the cyclic voltammetry (CV) measurements, the anodic peak current and peak charge related to the oxidative desorption of hydrogen significantly decrease due to the presence of methanol in KOH. This effect is attributed to the obstacles in hydrogen sorption due to the formation of a passivating layer on the Pd surface composed of both adsorbed methanol molecules and the intermediate products involving adsorbed CO. On the other hand, hydrogen desorbing from Pd electrode exerts influence on the kinetics of the reaction of methanol oxidation. Ni/Pd electrode undergoes considerable reactivation due to the potentiostatic saturation with hydrogen at −1.1 V, followed by the ease in hydrogen desorption. The CV measurements proved that, after such a treatment, the peak of hydrogen desorption partially overlaps the double peak of methanol oxidation and, in consequence, the rate of methanol oxidation is enhanced. The positive effect of hydrogen releasing from the electrode on the kinetics of the reaction of methanol oxidation is ascribed to the anti-poison behavior consisting in the reaction of hydrogen radicals with intermediates adsorbed on the Pd surface.

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“…One of them is intercalation, which enables introducing an intercalate (e.g., metal compounds) within the graphite structure. Our previous works revealed that graphite intercalation compound with nickel chloride (NiCl 2 -GIC) and with nickel chloride, iron chloride, and palladium chloride (NiCl 2 -FeCl 3 -PdCl 2 -GIC) are electrochemically active towards the processes of hydrogen sorption/desorption [1,2]. The composite described in our last paper concerning the electrochemical properties of EG/Ni/Pd has a markedly different structure [3].…”

Section: Introductionmentioning

confidence: 95%

Electrochemical properties of exfoliated graphite/nickel/palladium/carbon fibers composite

Krawczyk

Rozmanowski

2018

Ionics

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The goal of this work was to design a alternative material for hydrogen sorption/desorption by electrochemical devices. The investigations were focused on EG/Ni/Pd/C (exfoliated graphite/nickel/palladium/carbon fibers) composite. The deposition of carbon fibers differing in diameter and length over the EG/Ni/Pd significantly changes the electrochemical properties of the examined composite. SEM (scanning electron microscopy) analysis equipped with EDS (energy-dispersive spectrometer) detector revealed that external part of the investigated composite may involves palladium carbide.

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Electrochemical behavior of exfoliated NiCl2–graphite intercalation compound affected by hydrogen sorption

Cited by 22 publications

References 40 publications

Methanol Electrooxidation at Electrodes Made of Exfoliated Graphite/Nickel/Palladium Composite

Methanol Electrooxidation at Electrodes Made of Exfoliated Graphite/Nickel/Palladium Composite

Relationship between the reactions of hydrogen sorption/desorption and methanol oxidation on bifunctional Ni/Pd electrode in alkaline solution

Electrochemical properties of exfoliated graphite/nickel/palladium/carbon fibers composite

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