Studying Reduction in Solid Oxide Fuel Cell Activity with Density Functional Theory− Effects of Hydrogen Sulfide Adsorption on Nickel Anode Surface

Galea, Natasha M.; Kadantsev, Eugene S.; Ziegler, Tom

doi:10.1021/jp072450k

Cited by 38 publications

(46 citation statements)

References 47 publications

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“…Investigations of H 2 S adsorption on Cu(1 1 1) [73], Ni(1 1 1) [73,74] and Pt(1 1 1) [75] were previously carried out using DFT based on a (2 Â 2) slab (h H 2 S =1/4 ML). These studies also concluded that H 2 S binds through the S atom at a top site with the molecule sitting almost flat on the surface.…”

Section: Adsorption Of H 2 S Sh S and H On The Metal Surfacesmentioning

confidence: 99%

First-principles studies of H2S adsorption and dissociation on metal surfaces

2008

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Exposure of Pd-based hydrogen purification membranes to H,S. a common contaminant in coal gasification streams, can cause membrane performance to deteriorate, either by deactivating surface sites required for dissociative H, adsorption or by forming a low-permeability sulfide scale. In this work. the composition, structure, and catalytic activity of Pd4S, a surface scale commonly observed in Pd-membrane separation of hydrogen from sulfur-containing gas streams, were examined using a combination of experimental characterization and density functional theory (DFT) calculations. A Pd,S sample was prepared by exposing a 100 f1m Pd foil to H2S at 908 K. Both X-ray photoemission depth profiling and low energy ion scattering spectroscopic (LEISS) analysis reveal slight sulfur-enrichment of the top surface of the sample. This view is consistent with the predictions of DFT atomistic thermodynamic calculations. which identified S-terminated Pd,S surfaces as energetically favored over corresponding Pd-terminated surfaces. Activation barriers for H2 dissociation on the Pd,S surfaces were calculated. Although barriers are higher than on Pd(lll). transition state theory analysis identified reaction pathways on the S-terminated surfaces for which hydrogen dissociation rates are high enough to sustain the separation process at conditions relevant to gasification applications.

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Section: Adsorption Of H 2 S Sh S and H On The Metal Surfacesmentioning

confidence: 99%

First-principles studies of H2S adsorption and dissociation on metal surfaces

2008

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“… Energy profiles for adsorption and subsequent dissociation of H 2 S on Ni and other metal surfaces. (Adapted from Galea et al 72 . (left) and Alfonso 73 (right).)…”

Section: Kinetic Predictionsmentioning

confidence: 99%

Thermodynamics and Kinetics of the Interaction of Carbon and Sulfur with Solid Oxide fuel Cell Anodes

Offer

Mermelstein

Brightman

et al. 2009

Journal of the American Ceramic Society

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Fuel cells are likely to play a key role in any low-carbon economy. Solid oxide fuel cells (SOFCs) are currently capable of sustained and continuous operation on high-purity fuels, but they must demonstrate that they can overcome a number of challenges before they are commercially viable on a large scale. Fuels such as natural gas, and those derived from renewable sources such as gasified biomass, contain many contaminants, typically sulfur-and carbon-containing compounds. To address this it will be necessary to improve our understanding of failure modes in operating SOFCs, and act on this to reduce degradation rates. A combination of techniques will be needed to develop a rigorous approach to understanding and mitigating degradation. The intent of this article is to present a synopsis of the current state of the art in our understanding of the effect of carbon and sulfur on SOFC anodes. Emphasis is placed on the comparison between thermodynamic and kinetic models, and experimental validation of these. In particular the applicability of thermodynamic models to the study of such contaminants is questioned. Additionally the uses of multiscale kinetic models capable of predicting transient conditions are reviewed alongside recent analytical techniques necessary for their validation.

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“…Galea et al have carried out similar calculations. 9 Wang and Liu calculated the variation of adsorption energy as function of surface coverage varying from −2.64 eV at 1/16 to −1.40 eV at 10/16 .…”

Section: Chemisorption Of Sulfur On Nickelmentioning

confidence: 99%

Correlating Sulfur Poisoning of SOFC Nickel Anodes by a Temkin Isotherm

Hansen

2008

Electrochem. Solid-State Lett.

101

106

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Experimental data on sulfur's impact on solid oxide fuel cell ͑SOFC͒ nickel anodes have been analyzed using an isotherm for the sulfur coverage on the Ni surface: S = 1.45 − 9.53 ϫ 10 −5 T + 4.17 ϫ 10 −5 T ln Y, where Y is the ratio between the partial pressures of hydrogen sulfide and hydrogen. The loss of performance, P l , of the SOFC can be correlated by P l = k*͑ S − min ͒, where min Ͼ 0 depends on the current density and anode material. The data range covered is 700-1000°C, concentration of hydrogen sulfide 0.05-50 ppm.

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Studying Reduction in Solid Oxide Fuel Cell Activity with Density Functional Theory− Effects of Hydrogen Sulfide Adsorption on Nickel Anode Surface

Cited by 38 publications

References 47 publications

First-principles studies of H2S adsorption and dissociation on metal surfaces

First-principles studies of H2S adsorption and dissociation on metal surfaces

Thermodynamics and Kinetics of the Interaction of Carbon and Sulfur with Solid Oxide fuel Cell Anodes

Correlating Sulfur Poisoning of SOFC Nickel Anodes by a Temkin Isotherm

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