Comparison of the performance of Cu–CeO2–YSZ and Ni–YSZ composite SOFC anodes with H2, CO, and syngas

Costa-Nunes, Olga; Gorte, Raymond J.; Vohs, John M.

doi:10.1016/j.jpowsour.2004.09.022

Cited by 185 publications

(120 citation statements)

References 23 publications

Supporting

Mentioning

108

Contrasting

Unclassified

Order By: Relevance

“…The tapes were laminated under a pressure of 6 MPa at 340 K and then fired at 1823 K. During firing the pore formers combusted resulting in a dense, 50 μm thick YSZ electrolyte disc 1.25 cm in diameter sandwiched between 50 μm and 300 μm thick porous YSZ layers. The active components of both the anode and cathode were added using wet impregnation as has been described in detail previously [9][10][11][12][13][14][15] 2 . More detailed descriptions of these electrodes and their characteristics are given in previous publications [9][10][11][12][13][14][15].…”

Section: Methodsmentioning

confidence: 99%

Hydrogen Production Via CH4 and CO Assisted Steam Electrolysis

2007

Self Cite

View full text Add to dashboard Cite

Porous composite anodes consisting of a yttria-stabilized zirconia (YSZ) backbone that was impregnated with CeO 2 and various amounts of metallic components including Cu, Co and Pd were fabricated. The performance of these anodes was then tested in a solid oxide water electrolysis cell under conditions where the anode was exposed to the reducing gasses H 2 , CH 4 and CO. The reducing gasses were used to decrease the electrochemical potential of the cell and increase overall efficiency. The results of this study show that CuCeO 2 -YSZ anodes have low catalytic activity for the oxidation of CO and CH 4 and are not very effective in lowering the cell potential while operating in the reducing gas assisted mode. The addition of Co to the CuCeO 2 -YSZ anode resulted in a modest increase in the catalytic activity and enhanced the thermal stability of the anode. A Pd-C-CeO 2 -YSZ anode was found to have the highest catalytic activity of those tested and gave the largest reductions in the operating potential of the solid oxide electrolysis cell.

show abstract

Section: Methodsmentioning

confidence: 99%

Hydrogen Production Via CH4 and CO Assisted Steam Electrolysis

2007

Self Cite

View full text Add to dashboard Cite

show abstract

“…Comparison of polarization characteristics between model and data from Costa-Nunes et al 40 at 700 • C for hydrogen (97% H 2 + 3% H 2 O), syngas (25% H 2 + 25% CO + 50% N 2 ) and CO (99.9% CO + 0.1% CO 2 ). 41 at 750 • C for hydrogen (97% H 2 + 3% H 2 O), syngas #1 (47% H 2 + 47% CO + 6% H 2 O) and syngas #3 (42% H 2 + 42% CO + 16% H 2 O).…”

Section: A I (Mol Cm S) E Aimentioning

confidence: 99%

“…The polarization curves for this model are compared to experimental data from Costa-Nunes et al 40 at 700…”

mentioning

confidence: 99%

See 1 more Smart Citation

Investigation of a Combined Hydrogen and Oxygen Spillover Mechanism for Syngas Electro-Oxidation on Ni/YSZ

Ong

Hanna

Ghoniem

2016

J. Electrochem. Soc.

View full text Add to dashboard Cite

An accurate, comprehensive model for the individual and simultaneous electro-oxidation of H 2 and CO on Ni-YSZ is necessary to predict SOFC performance for a range of gaseous fuels. A mechanism that combines hydrogen (H) spillover to YSZ with oxygen (O) spillover to nickel is implemented in a previously-validated 1D-MEA model with detailed gas-phase transport and surface reforming kinetics in the anode. This model is then successfully fitted to a wide range of experimental polarization data for fuel mixtures. The H and O spillover pathways are then investigated in depth for two anode fuel mixtures: 20% H 2 + 80% N 2 and 20% H 2 + 80% CO. Although these studies confirm that H spillover is typically the dominant source of current, they also show that the current produced by O spillover is non-negligible at higher currents. Furthermore, it is observed that H 2 adsorption to nickel becomes the rate-limiting step at high currents in the hydrogen pathways, while the current produced by O spillover to C O(Ni) is never limited by the rate of CO adsorption. The model is then successfully compared to two independent lower temperature data sets. Together these results demonstrate that it is important to model both spillover pathways on Ni/YSZ and to account for rate-limiting H 2 adsorption at high currents. The thermochemical and electrochemical reaction mechanisms within a SOFC anode are complex, particularly when hydrocarbon species are involved.1-3 Elementary reaction steps are needed to accurately depict gas-phase chemistry, heterogeneous surface reforming, and heterogeneous charge-transfer reactions. Understanding the governing mechanisms for internal reforming and electrochemistry is paramount to optimize anode structure and operating conditions. More specifically, it is critical to identify the correct rate-limiting steps in these elementary mechanisms because those steps control the rate at which the cell can produce current. The elementary electro-oxidation reaction mechanisms for H 2 and CO require special attention because both of these fuels are dominant in practical SOFC fuel streams like reformed natural gas, coal syngas and biogas. 4 A couple of reaction mechanism types have been proposed to represent H 2 electrochemical oxidation at the triple-phase boundary (TPB) of Ni-YSZ: (1) hydrogen spillover and (2) oxygen spillover. Hydrogen (H) spillover mechanisms involve a charge-transfer step where hydrogen spills over from nickel to YSZ to react with oxygen. Oxygen (O) spillover mechanisms, on the other hand, involve a charge-transfer step where oxygen spills over from YSZ to nickel to react with hydrogen. Hydrogen electro-oxidation models typically select only one spillover pathway rather than implementing both the H and O spillover pathways simultaneously. Although a few researchers have used O spillover mechanisms to describe H 2 electro-oxidation, 5,6 the majority have implemented H spillover mechanisms.7-14 A few researchers have compared these two pathways and concluded that H spillover mechanisms are bett...

show abstract

“…Notably, however, when using Cu-CeO 2 -YSZ anodes in the presence of syngas mixtures, Costa-Nunes et al [12] found that Ceria was active for both the electrochemical oxidation of H 2 and CO, contemporarily. That is, no predominance of the H 2 electrooxidation was found, differently from Ni-YSZ anodes: possibly, this behavior could be attributed to the specific roles of Ceria and Cu, wherein the metal is almost inert and the spillover and diffusion reactions are blocked, while Ceria is active in both the oxidation of H 2 and CO.…”

Section: Introductionmentioning

confidence: 99%

Experimental and model analysis of the co-oxidative behavior of syngas feed in an Intermediate Temperature Solid Oxide Fuel Cell

Donazzi

Rahmanipour

Maestri

et al. 2016

Journal of Power Sources

View full text Add to dashboard Cite

-SOFCs). The activation of a co-oxidative route is a most distinguishing feature of Ce-based cells, compared to traditional SOFCs. SDC electrolyte supported ITSOFCs with Cu-Pd-CZ80 composite anodes and LSCF cathodes were tested under a wide range of operating conditions. Polarization and EIS measurements were collected at 600°C and 650°C with syngas mixtures (between 2.3 to 0.4 H2/CO ratio), H2/N2 mixtures (from 97 to 30% H2 v/v) and CO/CO2 mixtures (from 97 to 50% CO v/v). A 1D, dynamic and heterogeneous model of the cell was applied to analyze the polarization and the EIS curves. The kinetics of the reactions of H2 electrooxidation, CO electro-oxidation and O2 reduction were individually investigated and global power law rates were derived. The syngas experiments were simulated on a fully predictive basis and no parameter adjustment, confirming that the polarization behavior could be best reproduced exclusively by assuming the presence of the co-oxidative route. The IT-SOFCs were also exposed to biogas mixtures, revealing that the dry-reforming reaction was active. Milan, August 7 th 2015Dear Editor of the Journal of Power Sources, Please find attached our manuscript, entitled "Experimental and model analysis of the cooxidative behavior of syngas feed in an IT-SOFC" by Alessandro Donazzi, Morteza Rahmanipour, Matteo Maestri, Gianpiero Groppi, Luca Bardini, Alfonsina Pappacena and Marta Boaro, which we would like to submit for publication.In this paper, we present experimental and modeling results concerning the activation of a co-oxidative reaction mechanism in IT-SOFCs exposed to syngas mixtures. Novel, Ni-free, Ce-based IT-SOFCs are tested in a wide range of operative conditions, including biogas, syngas, H 2 /N 2 and CO/CO 2 mixtures. By means of model analysis, we show that the electro-oxidation of H 2 and the electro-oxidation of CO are active in parallel when syngas is fed to the cell, that is, the cell is able to directly oxidize CO in addition to H 2 . This is a most significant and promising result, associated to the presence of Ce in the anode formulation. For the first time in the case of ITSOFCs, the co-oxidative mechanism is numerically demonstrated. To accomplish this task, a onedimensional, dynamic and heterogeneous model is presented, which allows to predict both the polarization curves and the impedance spectroscopy curves. The model is based on fundamental conservation equations and also accounts for the presence of parasitic leakage currents, which characterize the behavior Ce electrolytes. A kinetic analysis is performed and power law rates are extracted for the electrocatalytic processes that are active in the cell.The work has not been previously submitted to the Journal of Power Sources, it has not been published previously in any form and is not under consideration for publication elsewhere. All the authors and the host authorities approve the manuscript.Thank you for your kind consideration. power law rates were derived. The syngas experiments were simulated on a fully predictive bas...

show abstract

Comparison of the performance of Cu–CeO2–YSZ and Ni–YSZ composite SOFC anodes with H2, CO, and syngas

Cited by 185 publications

References 23 publications

Hydrogen Production Via CH4 and CO Assisted Steam Electrolysis

Hydrogen Production Via CH4 and CO Assisted Steam Electrolysis

Investigation of a Combined Hydrogen and Oxygen Spillover Mechanism for Syngas Electro-Oxidation on Ni/YSZ

Experimental and model analysis of the co-oxidative behavior of syngas feed in an Intermediate Temperature Solid Oxide Fuel Cell

Contact Info

Product

Resources

About