A spectroscopic study of the adsorption and reactions of methanol, formaldehyde and methyl formate on clean and oxygenated Cu(110) surfaces

Sexton, B.A.; Hughés, A.E.; Avery, Neil R.

doi:10.1016/0039-6028(85)90423-6

Cited by 236 publications

(184 citation statements)

References 33 publications

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“…This was supported by well-detectable spectral changes characterized by a new four-peak structure, at 3.7-4.9, 8.1, 9.6 and 13.2 eV attributed to the 1a2, 6a l, 4b 2, the Lb., the 3b 2 , Sal' and the 4a l orbitals [22,28,29,30]. The UPS spectrum of adsorbed formate is in agreement with the SCP-MO molecular orbital calculations for this anion [31].…”

Section: Spectroscopic Features Of Adsorbed Hcoohsupporting

confidence: 68%

Adsorption of HCOOH on Rh(111) and its reaction with preadsorbed oxygen

Solymosi¹,

Kiss²,

Kovács³

1987

Surface Science Letters

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The interaction of formic acid with clean and oxygen-dosed Rh(lll) surfaces has been investigated by electron energy loss (in the electronic range), thermal desorption and photoelectron spectroscopy. Formic acid adsorbs readily on the Rh(l1l) surface at 100 K with a high sticking probability. Three adsorbed states have been distinguished: a condensed layer (T p = 170 K), a chemisorbed layer (T p = 202 K) and the formation of formate species. The latter is stable up to 200 K, but decomposes completely at 200-250 K. The major products are: H 2 (T p = 323 K) and CO 2 (T p = 255-290 K), but H:P (T p = 263 K) and CO (1~= 530 K) are also fonned.Preadsorbed oxygen exerted a readily observable influence on the interaction of HCOOH with the Rh(l11) surface. It increased the extent of dissociation of HCOOH and extended the region of stability of surface formate by at least 80-100 K. This was demonstrated by higher stability of photoemission peaks due to formate and by simultaneous production of CO 2 and H 20 with T p = 377-385 K at saturation oxygen coverage.

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Section: Spectroscopic Features Of Adsorbed Hcoohsupporting

confidence: 68%

Adsorption of HCOOH on Rh(111) and its reaction with preadsorbed oxygen

Solymosi¹,

Kiss²,

Kovács³

1987

Surface Science Letters

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“…1a, we also observed (spectra not shown) two distinctive yet less intense peaks at 2,933 and 2,848 cm -1 . These have been previously assigned to adsorbed formate species [20,21,30]. The first is a combination band of asymmetric O-C=O stretch and C-H inplane bend modes (m a (CO 2 -)+d(C-H)), while the second arises from the C-H stretch modes.…”

Section: Ftir Results At Steady Statementioning

confidence: 98%

“…These studies have also observed the presence of surface-bound formate species under reaction conditions [16] and also have measured the stability of these species in inert gas and hydrogen [17,18]. Compared with single crystal copper surfaces, the surface species observed on the oxide supported polycrystalline copper system are more complex because of the multi-faceted copper surfaces presented by the supported particles [14,17,[19][20][21] and the presence of species adsorbed on the support materials (e.g., alumina and ceria) as well as the support-metal interface [22]. More complex infrared spectra are observed which makes assignment more difficult than on the single crystals [23][24][25].…”

Section: Introductionmentioning

confidence: 94%

Isotope Effects in Methanol Synthesis and the Reactivity of Copper Formates on a Cu/SiO2 Catalyst

et al. 2008

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Here we investigate isotope effects on the catalytic methanol synthesis reaction and the reactivity of copper-bound formate species in CO 2 -H 2 atmospheres on Cu/SiO 2 catalysts by simultaneous IR and MS measurements, both steady-state and transient. Studies of isotopic variants (H/D, 12 C/ 13 C) reveal that bidentate formate dominates the copper surface at steady state. The steadystate formate coverages of HCOO (in 6 bar 3:1 H 2 :CO 2 ) and DCOO (in D 2 :CO 2 ) are similar and the steady-state formate coverages in both systems decrease by *80% from 350 K to 550 K. Over the temperature range 413 K-553 K, the steady-state methanol synthesis rate shows a weak H/D isotope effect (1.05 ± 0.05) with somewhat higher activation energies in H 2 :CO 2 (79 kJ/mole) than D 2 :CO 2 (71 kJ/mole) over the range 473 K-553 K. The reverse water gas shift (RWGS) rates are higher than methanol synthesis and also shows a weak positive H/D isotope effect with higher activation energy for H 2 /CO 2 than D 2 /CO 2 (108 vs. and 102 kJ/mole) The reactivity of the resulting formate species in 6 bar H 2 , 6 bar D 2 and 6 bar Ar is strongly dominated by decomposition back to CO 2 and H 2 . H 2 and D 2 exposure compared to Ar do not enhance the formate decomposition rate. The decomposition profiles on the supported catalyst deviate from first order decay, indicating distributed surface reactivity. The average decomposition rates are similar to values previously reported on single crystals. The average activation energies for formate decomposition are 90 ± 17 kJ/mole for HCOO and 119 ± 11 kJ/mole for DCOO. By contrast to the catalytic reaction rates, the formate decomposition rate shows a strong H/D kinetic isotope effect (H/D *8 at 413 K), similar to previously observed values on Cu(110).

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“…31 Similarly, there are a very limited number of studies investigating methyl formate interactions with water ice surfaces, with a majority of the work focusing on thermal processing on metallic surfaces. [32][33][34] Bertin and co-workers presented a study of methyl formate and acetic acid adsorption and desorption from ASW and CI films that combined experiment and theory. 6,35 This study focused on the interaction of submonolayer films with water ices using TPD and RAIRS at 80 K. The only studies at lower temperatures (16 K) have focused on the formation of methyl formate via the ion irradiation of methanol and CO ices.…”

Section: Introductionmentioning

confidence: 99%

Trapping and desorption of complex organic molecules in water at 20 K

Burke

Puletti

Woods

et al. 2015

The Journal of Chemical Physics

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Laser desorption time-of-flight mass spectrometry of ultraviolet photo-processed ices Rev. Sci. Instrum. 85, 104501 (2014); 10.1063/1.4896754The release of trapped gases from amorphous solid water films. II. "Bottom-up" induced desorption pathways J. Chem. Phys. 138, 104502 (2013) The formation, chemical, and thermal processing of complex organic molecules (COMs) is currently a topic of much interest in interstellar chemistry. The isomers glycolaldehyde, methyl formate, and acetic acid are particularly important because of their role as pre-biotic species. It is becoming increasingly clear that many COMs are formed within interstellar ices which are dominated by water. Hence, the interaction of these species with water ice is crucially important in dictating their behaviour. Here, we present the first detailed comparative study of the adsorption and thermal processing of glycolaldehyde, methyl formate, and acetic acid adsorbed on and in water ices at astrophysically relevant temperatures (20 K). We show that the functional group of the isomer dictates the strength of interaction with water ice, and hence the resulting desorption and trapping behaviour. Furthermore, the strength of this interaction directly affects the crystallization of water, which in turn affects the desorption behaviour. Our detailed coverage and composition dependent data allow us to categorize the desorption behaviour of the three isomers on the basis of the strength of intermolecular and intramolecular interactions, as well as the natural sublimation temperature of the molecule. This categorization is extended to other C, H, and O containing molecules in order to predict and describe the desorption behaviour of COMs from interstellar ices. C 2015 AIP Publishing LLC.[http://dx

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A spectroscopic study of the adsorption and reactions of methanol, formaldehyde and methyl formate on clean and oxygenated Cu(110) surfaces

Cited by 236 publications

References 33 publications

Adsorption of HCOOH on Rh(111) and its reaction with preadsorbed oxygen

Adsorption of HCOOH on Rh(111) and its reaction with preadsorbed oxygen

Isotope Effects in Methanol Synthesis and the Reactivity of Copper Formates on a Cu/SiO2 Catalyst

Trapping and desorption of complex organic molecules in water at 20 K

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