Thermal fragmentation of ethylene on the Rh(100) single crystal surface in the temperature range of 200–800 K

Slavin, A. J.; Bent, Brian E.; Kao, C.-T.; Somorjai, Gábor A.

doi:10.1016/0039-6028(88)90018-0

Cited by 48 publications

(68 citation statements)

References 36 publications

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“…Vinylidene has also been reported on the basis of HREELS results as one of several species produced in ethylene decomposition on Pt(100)(1×1) 312 and Rh (100). 333 In studies of the Pt(100)(1×1) system by Hatzikos and Masel, 312 a vibrational mode at 1580 cm -1 is attributed to vinylidenesindicating near sp 2 hybridization of the carbons analogous to the findings for Ru(001)/O.…”

Section: Vinylidenementioning

confidence: 78%

Mimicking Aspects of Heterogeneous Catalysis: Generating, Isolating, and Reacting Proposed Surface Intermediates on Single Crystals in Vacuum

1996

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Section: Vinylidenementioning

confidence: 78%

Mimicking Aspects of Heterogeneous Catalysis: Generating, Isolating, and Reacting Proposed Surface Intermediates on Single Crystals in Vacuum

1996

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“…Instead, vinylidene (CaCH 2 ) forms at 300 K, while an acetylinic species (C 2 H 2 ) forms above 400 K. There is evidence for the presence of a mixture of species that includes ethylidyne on the (2!1) Pt( 110) surface above 300 K (Yagasaki et al 1990). On the Rh(100) surface, ethylidyne forms above 300 K for surface coverages of greater than 0.5 monolayers, and subsequently dehydrogenates above 380 K to form a vinylidene surface intermediate (Slavin et al 1988). For surface coverages of less than 0.5 monolayers, a CCH surface species is formed.…”

Section: Resultsmentioning

confidence: 99%

Active sites and states in the heterogeneous catalysis of carbon–hydrogen bonds

Somorjai

Marsh

2005

Phil. Trans. R. Soc. A.

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C-H bond activation for several alkenes (ethylene, propylene, isobutene, cyclohexene and 1-hexene) and alkanes (methane, ethane, n-hexane, 2-methylpentane and 3-methylpentane) has been studied on the (111) crystal face of platinum as a function of temperature at low (10(-6) Torr) and high (>/=1 Torr) pressures in the absence and presence of hydrogen pressures (>/=10 Torr). Sum frequency generation (SFG) vibrational spectroscopy has been used to characterize the adsorbate structures and high pressure scanning tunnelling microscopy (HP-STM) has been used to monitor their surface mobility under reaction conditions during hydrogenation, dehydrogenation and CO poisoning. C-H bond dissociation occurs at low temperatures, approximately 250 K, for all of these molecules, although only at high pressures for the weakly bound alkanes because of their low desorption temperatures. Bond dissociation is known to be surface structure sensitive and we find that it is also accompanied by the restructuring of the metal surface. The presence of hydrogen slows down dehydrogenation and for some of the molecules it influences the molecular rearrangement, thus altering reaction selectivity. Surface mobility of adsorbates is essential to produce catalytic activity. When surface diffusion is inhibited by CO adsorption, ordered surface structures form and the reaction is poisoned. Ethylene hydrogenation is surface structure insensitive, while cyclohexene hydrogenation and dehydrogenation are structure sensitive. n-Hexane and other C6 alkanes form either upright or flat-lying molecules on the platinum surface which react to produce branched isomers or benzene, respectively.

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“…The carbon deposit was produced by exposing the surface to C,H4 at 300 K, and flashing the sample to 800 K [33]. After cooling to room temperature, the C-covered surface was exposed to oxygen.…”

Section: Effects Of Potassium On the Recombination Of Adsorbed 0 And mentioning

confidence: 99%

Photoelectron spectroscopic studies on the dissociation of CO on potassium-dosed Rh(111) surface

et al. 1989

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Adsorptionof CO has been investigated on clean and potassium-dosed Rh(ll1) surfaces by means of TDS, UPS, XPS and work function measurements.CO adsorbs molecularly at 90-300 K on Rh(ll1) dosed with K up to a monolayer coverage. No spectroscopic evidences were found for the dissociation of CO in the coadsorbed layer heated to near the onset temperature of CO desorption. A well detectable dissociation of CO was observed following electron bombardment of the coadsorbed layer. The effect of potassium on the reaction of adsorbed oxygen and carbon (produced by electron bombardment or by decomposition of ethylene) was also examined. Formation of chemisorbed CO at 8, = 0.33 occurred at 400-500 K, far below the desorption of CO from this surface. A promoting effect of potassium was established.It was concluded that CO desorbs from K-dosed Rh(ll1) without undergoing a significant dissociation, and the isotopic scrambling between labelled CO proceeds likely via a nondissociative mechanism.

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Thermal fragmentation of ethylene on the Rh(100) single crystal surface in the temperature range of 200–800 K

Cited by 48 publications

References 36 publications

Mimicking Aspects of Heterogeneous Catalysis: Generating, Isolating, and Reacting Proposed Surface Intermediates on Single Crystals in Vacuum

Mimicking Aspects of Heterogeneous Catalysis: Generating, Isolating, and Reacting Proposed Surface Intermediates on Single Crystals in Vacuum

Active sites and states in the heterogeneous catalysis of carbon–hydrogen bonds

Photoelectron spectroscopic studies on the dissociation of CO on potassium-dosed Rh(111) surface

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