Co adsorption on potassium promoted Fe(110)

Brodén, G.; Gafner, G.; Bonzel, H.P.

doi:10.1016/0039-6028(79)90139-0

Cited by 263 publications

(48 citation statements)

References 30 publications

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“…This was established from isotopic mixing experiments but was not confirmed by spectroscopic studies. The same conclusion was reached for Fe(lOO), Fe(ll1) [16], Ni(lOO) [17,18] and Ni(ll1) [19,20] surfaces, where the dissociation of CO was observed at 300-400 K. On the other hand, dissociation of CO has not been observed or reported for the K-promoted Ni(lOO) [21], Ru(001) Pt(ll1) [25-271, Pd(lOO) and Pd(ll0) surfaces in this temperature range. In the present study, the interaction of CO with K-dosed Rh(ll1) is examined by means of TPD, A+, UPS and XPS measurements, with particular attention to the dissociation of CO.…”

Section: Introductionsupporting

confidence: 62%

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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Section: Introductionsupporting

confidence: 62%

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

et al. 1989

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“…The addition of K has been known to increase the heat of chemisorption of CO on Fe surfaces, 63 increasing carbon deposition rates 54 and increasing the amount of carbon-based surface intermediates. 64 A third contribution to the C(1s) spectrum, at around 286 eV, has been assigned to carbon directly coordinated to oxygen, 65 and might suggest the presence of oxo-radical or carbonate-like species, as discussed by Bonzel and Krebs 59 or associatively bonded CO. In view of this, the high O/Fe and OH/Fe ratios observed in the Cu-promoted catalysts might be due to the presence of these surface species.…”

Section: Catalyst Phases As Studied By Fe(2p) Cu(2p) Si(2p) and K(2mentioning

confidence: 95%

The role of Cu on the reduction behavior and surface properties of Fe-based Fischer–Tropsch catalysts

Smit

Groot

Blume

et al. 2010

Phys. Chem. Chem. Phys.

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The effect of Cu on the reduction behavior and surface properties of supported and unsupported Fe-based Fischer-Tropsch synthesis (FTS) catalysts was investigated using in situ X-ray photoelectron spectroscopy (XPS) and in situ X-ray absorption spectroscopy (XAS) in combination with ex situ bulk characterization. During exposure to 0. After the reduction treatment, XPS showed that the concentration of oxygen and carbon surface species was higher in the presence of Cu. Furthermore, it was observed that the unsupported, Cu-containing catalyst showed higher CO 2 concentration in the product gas stream during and after reduction and Fe surface species were slightly oxidized after prolonged exposure to CO-H 2 . These observations suggest that, in addition to facilitating the reduction of the iron oxide phase, Cu also plays a direct role in altering the surface chemistry of Fe-based FTS catalysts.

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“…However, recent benchmarking density functional studies show that the molecular adsorption on metal is generally described correctly with van der Waals techniques such as the Grimme's method used here [36][37][38]. A direct comparison with experiment to confirm the accuracy of the van der Waals technique used is not possible due to the fact that the only available early experiment results, with adsorption energy estimates in the 1-2 eV range, [12,39,40] are not site-specific and not accurate enough to allow us to distinguish results at the ∼10 meV scale necessary here. Once the CO molecule is adsorbed on the surface, it decomposes into surface-adsorbed C and O atoms and the C atom diffuses into the Fe surface to complete the carburization process.…”

Section: Adsorptionmentioning

confidence: 99%

Insights on finite size effects in ab initio study of CO adsorption and dissociation on Fe 110 surface

Chakrabarty

Bouhali

Mousseau

et al. 2016

Journal of Applied Physics

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Adsorption and dissociation of hydrocarbons on metallic surfaces represent crucial steps on the path to carburization, eventually leading to dusting corrosion. While adsorption of CO molecules on Fe surface is a barrier-less exothermic process, this is not the case for the dissociation of CO into C and O adatoms and the diffusion of C beneath the surface, that are found to be associated with large energy barriers. In practice, these barriers can be affected by numerous factors that combine to favour the CO-Fe reaction such as the abundance of CO and other hydrocarbons as well as the presence of structural defects. From a numerical point of view, studying these factors is challenging and a step-by-step approach is necessary to assess, in particular, the influence of the finite box size on the reaction parameters for adsorption and dissociation of CO on metal surfaces. Here, we use density functional theory (DFT) total energy calculations with the climbing-image nudged elastic band (CI-NEB) method to estimate the adsorption energies and dissociation barriers for different CO coverages with surface supercells of different sizes. We further compute the effect of periodic boundary condition for DFT calculations and find that the contribution from van der Waals interaction in the computation of adsorption parameters is important as they contribute to correcting the finite-size error in small systems. The dissociation process involves carbon insertion into the Fe surface causing a lattice deformation that requires a larger surface system for unrestricted relaxation. We show that, in the larger surface systems associated with dilute CO-coverages, Cinsertion is energetically more favourable, leading to a significant decrease in the dissociation barrier. This observation suggests that a large surface system with dilute coverage is necessary for all similar metal-hydrocarbon reactions in order to study their fundamental electronic mechanisms, as an isolated phenomenon, free from finite-size effects.

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Co adsorption on potassium promoted Fe(110)

Cited by 263 publications

References 30 publications

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

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

The role of Cu on the reduction behavior and surface properties of Fe-based Fischer–Tropsch catalysts

Insights on finite size effects in ab initio study of CO adsorption and dissociation on Fe 110 surface

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