Oxidation of H2, CO and syngas mixtures on ceria and nickel pattern anodes

Patel, H.C.; Tabish, Asif Nadeem; Comelli, Filippo; Aravind, P.V.

doi:10.1016/j.apenergy.2015.05.049

Cited by 34 publications

(15 citation statements)

References 50 publications

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“…Other researchers [6,14,15,16,17] also studied the ceria electrochemistry in H 2 − H 2 O environments and proposed the reaction mechanisms, charge-transfer processes, and rate-determining step(s). However, these studies do not lead to a consensus on the charge-transfer mechanism and on the rate-determining M A N U S C R I P T…”

Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

A detailed look into hydrogen electrochemical oxidation on ceria anodes

Tabish

Patel

Schoonman

et al. 2018

Electrochimica Acta

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Using the Nernst-Planck-Poisson model and a detailed reaction mechanism, we studied the hydrogen electrochemical oxidation on a ceria anode. Resistances caused by surface kinetics, and bulk transport of oxide-ion vacancies and electrons are computed individually to identify the dominant resistive process. The effect of operating conditions like temperature and gas-phase composition on the polarization resistance is evaluated and compared with the experimental data obtained by Electrochemical Impedance Spectroscopy (EIS). The ratedetermining step is found to be the charge-transfer reaction in which hydrogen adsorbs at the surface oxide ions and forms hydroxyls along with the chargetransfer to adjacent cerium ions. Based on the rate-determining step, the exchange-current density is also calculated and validated with the experimental data.

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Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

A detailed look into hydrogen electrochemical oxidation on ceria anodes

Tabish

Patel

Schoonman

et al. 2018

Electrochimica Acta

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“…1−6 However, this study is not focusing on the characterization of an internal reforming gas such as CH 4 ; rather its aim is to shed some light on the effect of pure CO, which is in combination with the H 2 part of synthesis gas and used for external reforming. 4−8 …”

Section: Introductionmentioning

confidence: 99%

“…are typically reformed either internally or in an external reformer prior to the fuel cell. The internal reforming operation results in a higher efficiency, a simplified SOFC system, and hence lower costs of the whole power generation system due to the exclusion of the prereformer. − However, this study is not focusing on the characterization of an internal reforming gas such as CH 4 ; rather its aim is to shed some light on the effect of pure CO, which is in combination with the H 2 part of synthesis gas and used for external reforming. − …”

Section: Introductionmentioning

confidence: 99%

High-Temperature Carbon Deposition on Oxide Surfaces by CO Disproportionation

et al. 2016

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Carbon deposition due to the inverse Boudouard reaction (2CO → CO2 + C) has been studied on yttria-stabilized zirconia (YSZ), Y2O3, and ZrO2 in comparison to CH4 by a variety of different chemical, structural, and spectroscopic characterization techniques, including electrochemical impedance spectroscopy (EIS), Fourier-transform infrared (FT-IR) spectroscopy and imaging, Raman spectroscopy, and electron microscopy. Consentaneously, all experimental methods prove the formation of a more or less conducting carbon layer (depending on the used oxide) of disordered nanocrystalline graphite covering the individual grains of the respective pure oxides after treatment in flowing CO at temperatures above ∼1023 K. All measurements show that during carbon deposition, a more or less substantial surface reduction of the oxides takes place. These results, therefore, reveal that the studied pure oxides can act as efficient nonmetallic substrates for CO-induced growth of highly distorted graphitic carbon with possible important technological implications especially with respect to treatment in pure CO or CO-rich syngas mixtures. Compared to CH4, more carbon is generally deposited in CO under otherwise similar experimental conditions. Although Raman and electron microscopy measurements do not show substantial differences in the structure of the deposited carbon layers, in particular, electrochemical impedance measurements reveal major differences in the dynamic growth process of the carbon layer, eventually leading to less percolated islands and suppressed metallic conductivity in comparison to CH4-induced graphite.

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“…The charge transfer mechanism for electrochemical oxidation of H 2 and CO on ceria, as reported in our earlier submission (13), is most likely to resemble the ceria surface reduction process. The global oxidation state of ceria is considered to remain constant as the oxygen is supplied through the electrolyte.…”

Section: Electrochemical Oxidation With Ceria Pattern Anodesmentioning

confidence: 92%

“…In our previous work, we have reported the oxidation of pure H 2 and CO on nickel and ceria pattern cells but have not gone in details about the behaviour of mixtures. Only a single mixture composition was used (13). In this work we extend the results and discussion to multiple fuel compositions where kinetic parameters like activation energy for mixtures can be studied in detail.…”

Section: Introductionmentioning

confidence: 95%

Electrochemical Oxidation of CO/H₂ Mixtures on Ni and Ceria Pattern Anodes

Tabish¹,

Patel²,

Comelli³

et al. 2015

ECS Trans.

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Electrochemical oxidation of dry CO/H 2 mixtures on symmetrical Ni and ceria pattern anodes on YSZ electrolyte has been examined between 700-850 o C. Dry environment was used to exclude the possible side reactions like water-gas-shift (WGS) in the case of CO and CO/H 2 mixtures. Electrochemical impedance spectroscopy (EIS) showed 2.5 times higher polarization resistance for pure CO as compared to that of pure H 2 for Ni anodes and 5 times higher in case of ceria anodes. With the addition of small quantities of H 2 in CO, the polarization resistance dropped drastically. For all considered mixtures, the size of impedance arc was closer to that of pure H 2 as compared to that of pure CO. The activation energies obtained by equivalent circuit model (ECM) fitting of impedance spectra were similar to that of pure H 2 clearly indicating that H 2 is preferentially oxidized.

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Oxidation of H2, CO and syngas mixtures on ceria and nickel pattern anodes

Cited by 34 publications

References 50 publications

A detailed look into hydrogen electrochemical oxidation on ceria anodes

A detailed look into hydrogen electrochemical oxidation on ceria anodes

High-Temperature Carbon Deposition on Oxide Surfaces by CO Disproportionation

Electrochemical Oxidation of CO/H₂ Mixtures on Ni and Ceria Pattern Anodes

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Oxidation of H2, CO and syngas mixtures on ceria and nickel pattern anodes

Cited by 34 publications

References 50 publications

A detailed look into hydrogen electrochemical oxidation on ceria anodes

A detailed look into hydrogen electrochemical oxidation on ceria anodes

High-Temperature Carbon Deposition on Oxide Surfaces by CO Disproportionation

Electrochemical Oxidation of CO/H2 Mixtures on Ni and Ceria Pattern Anodes

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Electrochemical Oxidation of CO/H₂ Mixtures on Ni and Ceria Pattern Anodes