Sulfur Adsorption and Poisoning of Metallic Catalysts

Oudar, J.

doi:10.1080/03602458008066533

Cited by 302 publications

(131 citation statements)

References 42 publications

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“…The third effect, reconstruction of nickel surfaces by adsorbed sulfur, has been reported by a number of workers [28,32,33,[36][37][38]; for example, McCarroll and co-workers [37,38] found that sulfur adsorbed at near saturation coverage on a Ni(111) face was initially in a hexagonal pattern, but upon heating above 700 K reoriented to a distorted c(2 × 2) (100) overlayer. Oudar [36] reported that sulfur adsorbed on a Ni(810) surface caused decomposition to (100) and (410) facets.…”

Section: Parameter Definitionmentioning

confidence: 99%

“…Oudar [36] reported that sulfur adsorbed on a Ni(810) surface caused decomposition to (100) and (410) facets. During adsorption of H2S at RT, Ruan et al [33] observed surface restructuring of Ni(111) from a p(2 × 2) at low coverage to a missing-row (5 3 2)S  terrace structure (0.4 monolayer) sparsely covered with small, irregular islands composed of sulfur adsorbed on disordered nickel; upon annealing to 460 K for 5 min, the islands ordered to the (5 3 2)S  phase and their size increased, suggesting further diffusion of Ni atoms from the terraces.…”

Section: Parameter Definitionmentioning

confidence: 99%

“…Two important keys to reaching a deeper understanding of poisoning phenomena include (1) determining surface structures of poisons adsorbed on metal surfaces and (2) understanding how surface structure and hence adsorption stoichiometry change with increasing coverage of the poison. Studies of structures of adsorbed sulfur on single crystal metals (especially Ni) [3,28,[32][33][34][35][36][37][38] provide such information. They reveal, for example, that sulfur adsorbs on Ni(100) in an ordered p(2 × 2) overlayer, bonded to four Ni atoms at S/Nis < 0.25 and in a c(2 × 2) overlayer to two Ni atoms for S/Nis = 0.25-0.50 (see Figure 5; Nis denotes a surface atom of Ni); saturation coverage of sulfur on Ni(100) occurs at S/Nis = 0.5.…”

Section: Parameter Definitionmentioning

confidence: 99%

See 2 more Smart Citations

Heterogeneous Catalyst Deactivation and Regeneration: A Review

2015

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Deactivation of heterogeneous catalysts is a ubiquitous problem that causes loss of catalytic rate with time. This review on deactivation and regeneration of heterogeneous catalysts classifies deactivation by type (chemical, thermal, and mechanical) and by mechanism (poisoning, fouling, thermal degradation, vapor formation, vapor-solid and solid-solid reactions, and attrition/crushing). The key features and considerations for each of these deactivation types is reviewed in detail with reference to the latest literature reports in these areas. Two case studies on the deactivation mechanisms of catalysts used for cobalt Fischer-Tropsch and selective catalytic reduction are considered to provide additional depth in the topics of sintering, coking, poisoning, and fouling. Regeneration considerations and options are also briefly discussed for each deactivation mechanism.

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Section: Parameter Definitionmentioning

confidence: 99%

Section: Parameter Definitionmentioning

confidence: 99%

Section: Parameter Definitionmentioning

confidence: 99%

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Heterogeneous Catalyst Deactivation and Regeneration: A Review

2015

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“…Generally it contains 50-75% CH 4 , 50-25% CO 2 , 0-10% N 2 , and 0-3% H 2 S. Biogas may be combusted to produce electricity or can be converted to synthesis gas by reforming over Rh or Ni catalyst [1,2,3,4]. However, the presence of H 2 S or other sulfur containing compounds is a major problem for reforming of biogas due to its poisoning effect on most transition metals [5]. Although poisoning of Ni in presence of H 2 S is well known, the mechanistic details of poisoning and regeneration are lacking in the present literature, particularly in biogas environment.…”

Section: Introductionmentioning

confidence: 99%

A detailed kinetic model for biogas steam reforming on Ni and catalyst deactivation due to sulfur poisoning

Appari¹,

Janardhanan²,

Bauri³

et al. 2014

Applied Catalysis A: General

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This paper deals with the development and validation of a detailed kinetic model for steam reforming of biogas with and without H 2 S. The model has 68 reactions among 8 gasphase species and 18 surface adsorbed species including the catalytic surface. The activation energies for various reactions are calculated based on unity bond index-quadratic exponential potential (UBI-QEP) method. The whole mechanism is made thermodynamically consistent by using a previously published algorithm. Sensitivity analysis is carried out to understand the influence of reaction parameters on surface coverage of sulfur. The parameters describing sticking and desorption reactions of H 2 S are the most sensitive ones for the formation of adsorbed sulfur. The mechanism is validated in the temperature range of 873-1200 K for biogas free from H 2 S and 973-1173 K for biogas containing 20-108 ppm H 2 S. The model predicts that during the initial stages of poisoning sulfur coverages are high near the reactor inlet; however, as the reaction proceeds further sulfur coverages increase towards the reactor exit. In the absence of sulfur CO and H atoms are the dominant surface adsorbed species. High temperature operation can significantly mitigate sulfur adsorption and hence the saturation sulfur coverages are lower compared to low temperature operation. Low temperature operation can lead to full deactivation of the catalyst. The model predicts saturation coverages that are comparable to experimental observation.

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“…Whether a species is a poison depends upon its adsorption strength relative to other species competing for active sites. For many reactions, such as methanation, methanol synthesis and Fischer-Tropsch synthesis, over group 8-11 metal catalysts, sulphur is a known poison [1]. To be able to interpret quantitatively the extent and nature of poisoning by sulphur, it is essential to know the structure and bonding of sulphur to metal atoms at the surface.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of hydrogen sulphide over rhodium/silica and rhodium/alumina at 293 and 873 K, with co-adsorption of carbon monoxide and hydrogen

2017

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In this study, we have examined the adsorption of hydrogen sulphide and carbon monoxide over rhodium/ silica and rhodium/alumina catalysts. Adsorption of hydrogen sulphide was measured at 293 and 873 K and at 873 K in a 1:1 ratio with hydrogen. At 293 K, over Rh/ silica, hydrogen sulphide adsorption capacity was similar to that of carbon monoxide; however, over Rh/alumina, the carbon monoxide adsorption capacity was higher, probably due to the formation of Rh I (CO) 2 . Over Rh/silica, the primary adsorbed state was HS(ads), in contrast to Rh/alumina, where the H 2 :S ratio was 1:1 indicating that the adsorbed state was S(ads). Competitive adsorption between CO and H 2 S over Rh/silica and Rh/alumina revealed adsorption sites on the metal that only adsorbed carbon monoxide, only adsorbed hydrogen sulphide or could adsorb both species. At 873 K, hydrogen sulphide adsorption produced the bulk sulphide Rh 2 S 3 ; however, when a 1:1 H 2 :H 2 S mixture was used formation of the bulk sulphide was inhibited and a reduced amount of hydrogen sulphide was adsorbed.

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Sulfur Adsorption and Poisoning of Metallic Catalysts

Cited by 302 publications

References 42 publications

Heterogeneous Catalyst Deactivation and Regeneration: A Review

Heterogeneous Catalyst Deactivation and Regeneration: A Review

A detailed kinetic model for biogas steam reforming on Ni and catalyst deactivation due to sulfur poisoning

Adsorption of hydrogen sulphide over rhodium/silica and rhodium/alumina at 293 and 873 K, with co-adsorption of carbon monoxide and hydrogen

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