Density functional theory study of hydrogen sulfide dissociation on bi-metallic Ni–Mo catalysts

Albenze, Erik; Shamsi, Abolghasem

doi:10.1016/j.susc.2006.06.006

Cited by 30 publications

(25 citation statements)

References 43 publications

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“…Previous DFT studies found the same preferred site and binding configuration for SH on Pt(1 1 1) at h SH = 1/4 ML [75]. Using DFT, examination of SH adsorption on Ni(1 1 1) at 1/9 ML coverage was reported [57]. The bridge-fcc and bridge-hcp sites were found to be the lowest in energy which is in line with our findings.…”

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

confidence: 89%

“…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. DFT studies of H 2 S adsorption on Ni(1 1 1) and Pd(1 1 1) at h H 2 S = 1/9 ML employing a 3-4 layer (3 Â 3) slab were reported [56,57]. These works lead to similar conclusions: i.e.…”

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

confidence: 65%

“…The dissociation of H 2 S was found to have low barriers and high exothermicities. Similar studies on the corresponding Ni(1 1 1), Fe(1 0 0) and Fe (1 1 0) surfaces were also performed [57][58][59]. The decomposition of H 2 S on these surfaces was also predicted to be a facile process.…”

Section: Introductionmentioning

confidence: 70%

“…The dissociation pathway studied here involves sequential abstraction of H atoms from H 2 S [56][57][58][59]. This sequential S-H scission gives rise to surface SH and surface S intermediates (i.e.…”

Section: Computational Approachmentioning

confidence: 99%

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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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