Sulfur poisoning of hydrogen and carbon monoxide adsorption on supported nickel

Bartholomew, Calvin H.; Pannell, Richard B.

doi:10.1016/0166-9834(82)80172-3

Cited by 17 publications

(12 citation statements)

References 17 publications

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“…Bartholomew and Pannel experimentally deduced a linear relationship between the amount of sulfur adsorption on a nickel surface and the reduction in the corresponding molecular hydrogen adsorption. 6 This study concluded that no further adsorption of molecular hydrogen occurred once a sulfur surface coverage of 70% was obtained. The third aim of our study considers the geometrical, thermodynamical, and kinetic effects of sulfur coverage (θ S ) on consecutive hydrogen molecule adsorptions.…”

Section: Hydrogen Adsorption On Planar Nickel Surface Withmentioning

confidence: 88%

“…Currently, a nickel composite (nickel−yttria-stabilized-zirconia, Ni−YSZ) is the most commonly used SOFC anode material . Despite several experimental − and theoretical − studies concerning adsorbed sulfur species on nickel surfaces, little has been published in terms of theoretical studies on the manner and degree by which sulfur-based contaminants affect the performance of a SOFC.…”

Section: Introductionmentioning

confidence: 99%

“…Even in earlier literature, the blocking of vacant adsorption sites was considered the main mechanism behind sulfur poisoning . On the basis of a number of different experimental reactions, the catalytic activity of a nickel surface is established to decrease due to the adsorption of sulfur. ,,16a,, Sasaki et al have recently published comprehensive experimental data concerning H 2 S(g) poisoning of the Ni−YSZ anode. At operating temperatures of 1000 °C, Sasaki demonstrated that overall electrochemical cell activity (voltage) decreased by continuously larger amounts corresponding to increased H 2 S(g) concentration (up to 5 ppm) in the anode feed.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

2007

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To gain insight into the degree by which sulfur-based contaminants poison the solid oxide fuel cell (SOFC) anode, we examine adsorption and dissociation of consecutive molecules of hydrogen sulfide on a nickel (111) surface. Preferred adsorption sites, energies, transition states, and kinetic barriers are calculated for the resulting species, *SH x (x ) 0 -2) and *H. Systematically larger amounts of adsorbed sulfur (0, 25, 50, 75, 100%) are calculated to determine the most energetically favorable sulfur surface coverage. The removal of existing sulfur surface atoms is studied to probe the irreversibility of the hydrogen sulfide adsorption reaction. The extent of molecular hydrogen adsorption at increasing surface sulfur coverages allows us to conclude that the presence of even 25% surface sulfur can reduce molecular hydrogen adsorption on the surface by half. Concurring with experimental data, our research demonstrates equilibrium coverage of 50% adsorbed sulfur on the surface. Due to the considerable exothermic nature of the hydrogen sulfide adsorption and dissociation reaction, partial irreversibility of the reaction is exhibited. This irreversibility proves challenging during attempts to remove surface sulfur and regain the original electrochemical activity.

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Section: Hydrogen Adsorption On Planar Nickel Surface Withmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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

2007

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“…Bartholomew and Pannell also showed an inverse linear relationship between S ads and hydrogen (H ads ) surface coverage on supported Ni particles [10]. Additionally, DFT-based models of Ni(111) surfaces suggest that H ads coverage approaches zero as S ads approaches 100% coverage [11][12].…”

Section: Introductionmentioning

confidence: 95%

Understanding Performance Losses at Ni-Based Anodes Due to Sulphur Exposure

Birss¹,

Deleebeeck²,

Paulson³

et al. 2011

ECS Trans.

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While Ni-YSZ (yttria-stabilized zirconia) cermets have excellent properties for use as solid oxide fuel cell (SOFC) anodes, they are susceptible to performance loss in the presence of sulfur (S) in the fuel stream. In this work, we have electrochemically determined the extent of poisoning and recovery of Ni-YSZ electrolytesupported half-cells in 5 ppm H 2 S (in H 2 ) between 600 and 850°C, comparing these results with S adsorption/removal data obtained using TGA. It is shown by both approaches that the coverage of Ni by adsorbed S species (S ads ) increases as the temperature decreases, as expected. However, the extent of S ads coverage, determined from performance loss, is significantly less than predicted from the mass gain during S adsorption. Furthermore, anodes exposed to H 2 S at 600°C show an unusual irreversible S poisoning effect when polarized at 250 mV, not seen in TGA experiments.

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“…2,3 This has been suggested to be due to the reversible formation of sub-monolayer coverages of adsorbed sulphur (S ads ) on the Ni surface, [2][3][4][5][6][7][8][9] blocking surface sites and causing deleterious and irreversible surface reconstruction. 10 Both experimental 11 and theoretical (density functional theory 12,13 ) work have suggested an inverse linear relationship between the surface coverage of S ads and adsorbed hydrogen (H ads ) on Ni, with the H ads coverage approaching zero as S ads approaches 100% coverage (one S ads for two surface Ni atoms).…”

Section: Introductionmentioning

confidence: 99%

Activation of H2 oxidation at sulphur-exposed Ni surfaces under low temperature SOFC conditions

Deleebeeck

Shishkin

Addo

et al. 2014

Phys. Chem. Chem. Phys.

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Ni-YSZ (yttria-stabilized zirconia) cermets are known to be very good anodes in solid oxide fuel cells (SOFCs), which are typically operated at 700-1000 °C. However, they are expected to be increasingly degraded as the operating temperature is lowered in the presence of H2S (5-10 ppm) in the H2 fuel stream. However, at 500 to 600 °C, a temperature range rarely examined for sulphur poisoning, but of great interest for next generation SOFCs, we report that H2S-exposed Ni-YSZ anodes are catalytic towards the H2 oxidation reaction, rather than poisoned. By analogy with bulk Ni3S2/YSZ anodes, shown previously to enhance H2 oxidation kinetics, it is proposed that a thin layer of Ni sulphide, akin to Ni3S2, is forming, at least at the triple point boundary (TPB) region under our conditions. To explain why Ni3S2/YSZ is so active, it is shown from density functional theory (DFT) calculations that the O(2-) anions at the Ni3S2/YSZ TPB are more reactive towards hydrogen oxidation than is O(2-) at the Ni/YSZ TPB. This is accounted for primarily by structural transformations of Ni3S2 during H2 oxidation, rather than by the electronic properties of this interface. To understand why a thin layer of Ni3S2 could form when a single monolayer of sulphur on the Ni surface is the predicted surface phase under our conditions, it is possible that the reaction of H2 with O(2-), forming water, prevents sulphur from re-equilibrating to H2S. This may then promote Ni sulphide formation, at least in the TPB region.

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Sulfur poisoning of hydrogen and carbon monoxide adsorption on supported nickel

Cited by 17 publications

References 17 publications

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

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

Understanding Performance Losses at Ni-Based Anodes Due to Sulphur Exposure

Activation of H2 oxidation at sulphur-exposed Ni surfaces under low temperature SOFC conditions

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