A near edge X-ray absorption fine structure study of the adsorption of pyrrole and N-methylpyrrole on Pt(111): Orientation and dissociation of the adsorbed molecules

Tourillon, G.; Raaen, S.; Skotheim, Terje A.; Sagurton, M.; Garrett, R. F.; Williams, Gwyn

doi:10.1016/s0039-6028(87)80261-3

Cited by 38 publications

(20 citation statements)

References 23 publications

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“…For the structurally related molecules pyrrole and pyridine, upright standing surface species have been observed on Pt(111), previously. The latter forms a Pt‐bound α‐pyridyl.…”

Section: Resultsmentioning

confidence: 70%

Model Catalytic Studies of Novel Liquid Organic Hydrogen Carriers: Indole, Indoline and Octahydroindole on Pt(111)

Schwarz

Bachmann

Silva

et al. 2017

Chemistry A European J

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Indole derivatives were recently proposed as potential liquid organic hydrogen carriers (LOHC) for storage of renewable energies. In this work, we have investigated the adsorption, dehydrogenation and degradation mechanisms in the indole/indoline/octahydroindole system on Pt(111). We have combined infrared reflection absorption spectroscopy (IRAS), X-ray photoelectron spectroscopy (XPS) and DFT calculations. Indole multilayers show a crystallization transition at 200 K, in which the molecules adopt a strongly tilted orientation, before the multilayer desorbs at 220 K. For indoline, a less pronounced restructuring transition occurs at 150 K and multilayer desorption is observed at 200 K. Octahydroindole multilayers desorb already at 185 K, without any indication for restructuring. Adsorbed monolayers of all three compounds are stable up to room temperature and undergo deprotonation at the NH bond above 300 K. For indoline, the reaction is followed by partial dehydrogenation at the 5-membered ring, leading to the formation of a flat-lying di-σ-indolide in the temperature range from 330-390 K. Noteworthy, the same surface intermediate is formed from indole. In contrast, the reaction of octahydroindole with Pt(111) leads to the formation of a different intermediate, which originates from partial dehydrogenation of the 6-membered ring. Above 390 K, all three compounds again form the same strongly dehydrogenated and partially decomposed surface species.

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“…For the structurally related molecules pyrrole and pyridine, upright standing surface species have been observed on Pt(111), previously. The latter forms a Pt‐bound α‐pyridyl.…”

Section: Resultsmentioning

confidence: 70%

Model Catalytic Studies of Novel Liquid Organic Hydrogen Carriers: Indole, Indoline and Octahydroindole on Pt(111)

Schwarz

Bachmann

Silva

et al. 2017

Chemistry A European J

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“…The adsorption of pyrrole on both Pt(111) 7 and Rh(111) 8 metal surfaces has been studied to provide some insight into the five-membered heterocyclic bonding characteristics. The studies mentioned above showed that the adsorption geometry of pyrrole is sensitive to the type of metal substrate.…”

Section: Introductionmentioning

confidence: 99%

Pyrrole Hydrogenation over Rh(111) and Pt(111) Single-Crystal Surfaces and Hydrogenation Promotion Mediated by 1-Methylpyrrole: A Kinetic and Sum-Frequency Generation Vibrational Spectroscopy Study

Kliewer¹,

Bieri²,

Somorjai³

2008

J. Phys. Chem. C

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Sum-frequency generation (SFG) surface vibrational spectroscopy and kinetic measurements using gas chromatography have been used to study the adsorption and hydrogenation of pyrrole over both Pt(111) and Rh(111) single-crystal surfaces at Torr pressures (3 Torr pyrrole, 30 Torr H 2 ) to form pyrrolidine and the minor product butylamine. Over Pt(111) at 298 K it was found that pyrrole adsorbs in an upright geometry cleaving the N-H bond to bind through the nitrogen evidenced by SFG data. Over Rh(111) at 298 K pyrrole adsorbs in a tilted geometry relative to the surface through the π-aromatic system. A pyrroline surface reaction intermediate, which was not detected in the gas phase, was seen by SFG during the hydrogenation over both surfaces. Significant enhancement of the reaction rate was achieved over both metal surfaces by adsorbing 1-methylpyrrole before reaction. SFG vibrational spectroscopic results indicate that reaction promotion is achieved by weakening the bonding between the N-containing products and the metal surface because of lateral interactions on the surface between 1-methylpyrrole and the reaction species, reducing the desorption energy of the products. It was found that the ring-opening product butylamine was a reaction poison over both surfaces, but this effect can be minimized by treating the catalyst surfaces with 1-methylpyrrole before reaction. The reaction rate was not enhanced with elevated temperatures, and SFG suggests desorption of pyrrole at elevated temperatures.

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“…In recent years, functionalized pyrroles and related molecules have attracted increasing attention as self‐assembling adsorbates 7. Pyrrole has been studied on several metal surfaces, including Pt(111),8 Pd(111),9 Rh(111),10 and Cu(100) 11. Whilst little is known about potential energy landscapes and interactions between molecules, pyrrole is usually found to adsorb in a flat‐lying geometry at low coverages, often moving to a tilted geometry at higher coverages.…”

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confidence: 99%

Quantum Influences in the Diffusive Motion of Pyrrole on Cu(111)

et al. 2013

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Classical diffusion—quantum barrier: On Cu(111), pyrrole diffuses in channels, hopping between adjacent bridge sites over a barrier above hollow sites. The motion of the center of mass can be described classically; however, the activation barrier arises from the quantum character of internal vibrational modes that are largely unexcited during the motion. The unique helium spin‐echo experiment is indicated by the green sphere and arrows

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A near edge X-ray absorption fine structure study of the adsorption of pyrrole and N-methylpyrrole on Pt(111): Orientation and dissociation of the adsorbed molecules

Cited by 38 publications

References 23 publications

Model Catalytic Studies of Novel Liquid Organic Hydrogen Carriers: Indole, Indoline and Octahydroindole on Pt(111)

Model Catalytic Studies of Novel Liquid Organic Hydrogen Carriers: Indole, Indoline and Octahydroindole on Pt(111)

Pyrrole Hydrogenation over Rh(111) and Pt(111) Single-Crystal Surfaces and Hydrogenation Promotion Mediated by 1-Methylpyrrole: A Kinetic and Sum-Frequency Generation Vibrational Spectroscopy Study

Quantum Influences in the Diffusive Motion of Pyrrole on Cu(111)

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