Synthesis of formate on K-modified Cu(110) based on coadsorption of H and CO2

Onsgaard, J.; Christensen, S.V.; Godowski, P. J.; Nerlov, Jesper; Quist, S.

doi:10.1016/s0039-6028(96)01177-6

Cited by 12 publications

(6 citation statements)

References 32 publications

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“…In the mass range from 2 to 90 amu, we observe desorption signals from H 2 , CH 4 , C 2 H 4 , C 2 H 6 , and C 3 H 6 species with m/e at 2, 14, 15, 16, 27,28,29,30,38,39,40,41, and 42. Some typical multiplexed thermal desorption spectra of 2, 16, 27, 30, and 41 amu signals are illustrated in Figure 10 as a function of CH 3 exposures.…”

Section: Surface Reaction Of Ch 3 (Ads) On Cu(110)mentioning

confidence: 92%

“…Figure 4 shows the UPS spectra taken as a function of CH 3 exposure on a clean Cu(110) surface at 400 K. The clean Cu(110) surface exhibits a surface state (Cu ss ) at 0.4 eV BE, which is attributed to the emission from the s-p band of copper, and three surface resonances at 2.5 (Cu res1 ), 3.4 (Cu res2 ), and 4.9 eV (Cu res3 ) due to the emission from the Cu 3d band in agreement with those reported previously. 40,41 Obviously, the signal intensities of the Cu surface state and resonances decrease when the CH 3 exposure and the adsorbate coverage are increased. To see the clear effect of CH 3 adsorption, we take the difference spectra between the CH 3 -exposed sample and the clean Cu surface.…”

Section: Chemisorption Characteristics Of Ch 3 (Ads) On Cu(110)mentioning

confidence: 99%

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Chemisorption and Reaction Characteristics of Methyl Radicals on Cu(110)

et al. 2004

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Methyl radicals are generated by pyrolysis of azomethane, and the condition for achieving neat adsorption on Cu(110) is described for studying their chemisorption and reaction characteristics. The radical-surface system is examined by X-ray photoemission spectroscopy, ultraviolet photoemission spectroscopy, temperature-programmed desorption, low-energy electron diffraction (LEED), and high-resolution electron energy loss spectroscopy under ultrahigh vacuum conditions. It is observed that a small fraction of impinging CH3 radicals decompose into methylene possibly on surface defect sites. This type of CH2 radical has no apparent effect on CH3(ads) surface chemistry initiated by dehydrogenation to form active CH2(ads) followed by chain reactions to yield high-mass alkyl products. All thermal desorption products, such as H2, CH4, C2H4, C2H6, and C3H6, are detected with a single desorption peak near 475 K. The product yields increase with surface coverage until saturation corresponding to 0.50 monolayer of CH3(ads). The mass distribution is, however, invariant with initial CH3(ads) coverage, and all desorbed species exhibit first-order reaction kinetics. LEED measurement reveals a c(2 × 2) adsorbate structure independent of the amount of gaseous exposure. This strongly suggests that the radicals aggregate into close-packed two-dimensional islands at any exposure. The islanding behavior can be correlated with the reaction kinetics and is deemed to be essential for the chain propagation reactions. Some relevant aspects of the CH3/Cu(111) system are also presented. The new results are compared with those of prior studies employing methyl halides as radical sources. Major differences are found in the product distribution and desorption kinetics, and these are attributed to the influence of surface halogen atoms present in those earlier investigations.

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Section: Surface Reaction Of Ch 3 (Ads) On Cu(110)mentioning

confidence: 92%

Section: Chemisorption Characteristics Of Ch 3 (Ads) On Cu(110)mentioning

confidence: 99%

Chemisorption and Reaction Characteristics of Methyl Radicals on Cu(110)

et al. 2004

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“…Formate can furthermore be formed through coadsorption of hydrogen and carbon dioxide on Cu͑110͒ promoted with potassium. 4 Recent studies of formic and acetic acids adsorbed on Cu have revealed interesting phenomena for these adsorbate systems, where adsorbateinduced surface reconstruction-roughening has been reported. [5][6][7][8] Similar effects have also been reported earlier for adsorption on, e.g., Al͑111͒.…”

Section: Introductionmentioning

confidence: 99%

The bonding of simple carboxylic acids on Cu(110)

Karis

Hasselstrøm

Wassdahl

et al. 2000

The Journal of Chemical Physics

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We present a study of the bonding of formate (HCOO) and acetate (CH3COO) chemisorbed on Cu(110) using core level spectroscopies in combination with theoretical calculations. For the first time, we apply x-ray emission spectroscopy (XES) to these systems. When XES is used in conjunction with x-ray absorption spectroscopy (XAS) and ab initio calculations, new information about the electronic interaction in the adsorbate–substrate system is provided. In particular, we have used the azimuthal orientation of the COO–surface bond on the (110) surface, to make a complete partition into x, y, and z orbital contributions. The surface bond is found to be predominantly ionic. For the case of adsorbed formate, the covalent bonding is dominated by 6a1/7a1, (σ)-type, frontier orbitals, interacting with the Cu valence band. The resulting hybrid orbitals form a distribution of states that cross the Fermi level. The contribution from adsorbate π-type orbitals is small. The chemical bond formation of adsorbed acetate is very similar to that of formate. In addition, states with metal character have been identified for the outermost CH3-group of acetate. These are delocalized states of mainly local σ-character. The spectral features due to states of local π-character in the adsorbed acetate are well described within the framework of hyperconjugation.

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“…Solved CO2(-) species does not follow disproportionation to CO3 with increase in temperature. The CO2(-) readily reacts with coadsorbed hydrogen to form formate on K/Cu(110) [20,21]. Thus, reactivity of the interface in aspect of methanol synthesis is dependent on the ability of creation of the stable bending CO2(-) molecules among adsorbing CO2.…”

Section: Discussionmentioning

confidence: 99%

Photoemission Study of CO₂adsorbed on K/Cu(110). Analysis of Adsorbate Induced Structures

Godowski

Onsgaard²,

Hoffmann

et al. 1999

Acta Phys. Pol. A

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Using photoemission spectroscopy, adsorption and reaction of CO2 on potassium modified Cu(110) were studied. In agreement with published results of thermally programmed desorption, apart from carbonate and carbon monoxide as the disproportionation reaction products, a linear CO 2 molecule and a bent active CO2 (-) species were identified. The reaction paths are independent on the potassium precoverage but the number of CO3 molecules increases with the number of potassium adatoms. The presence of the CO2(-), stable up to 200 K, suitable for the reactivity of the interface in respect of the methanol synthesis, could be confirmed in the complex valence band spectra by occurrence of the characteristic peak at binding energy of 6.8 eV.

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Synthesis of formate on K-modified Cu(110) based on coadsorption of H and CO2

Cited by 12 publications

References 32 publications

Chemisorption and Reaction Characteristics of Methyl Radicals on Cu(110)

Chemisorption and Reaction Characteristics of Methyl Radicals on Cu(110)

The bonding of simple carboxylic acids on Cu(110)

Photoemission Study of CO₂adsorbed on K/Cu(110). Analysis of Adsorbate Induced Structures

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Synthesis of formate on K-modified Cu(110) based on coadsorption of H and CO2

Cited by 12 publications

References 32 publications

Chemisorption and Reaction Characteristics of Methyl Radicals on Cu(110)

Chemisorption and Reaction Characteristics of Methyl Radicals on Cu(110)

The bonding of simple carboxylic acids on Cu(110)

Photoemission Study of CO2adsorbed on K/Cu(110). Analysis of Adsorbate Induced Structures

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Product

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Photoemission Study of CO₂adsorbed on K/Cu(110). Analysis of Adsorbate Induced Structures