A DFT Study of the Adsorption and Dissociation of CO on Fe(100): Influence of Surface Coverage on the Nature of Accessible Adsorption States

Bromfield, Tracy C.; Ferré, Daniel Curulla; Niemantsverdriet, J.W.

doi:10.1002/cphc.200400452

Cited by 114 publications

(152 citation statements)

References 29 publications

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“…The activation energy (E Forward ) of CO dissociation on clean Fe (100) was 1.13 eV ( Table 2) and the recombination energy (E Back ) was 2.28 eV showing the exothermic nature of the dissociation process ( Table 2). The IS, TS and FS at 0 ML coverage of H are in good agreement with the other reported calculations of Wang et al [31], Tracy et al [32], Xun-hua et al [33], and Elahifard et al [37]. The direct dissociation of CO in the presence of coadsorbed H present slight variations of forward barrier to all coverages studied, where 1.06 eV, 1.16 eV and 0.90 eV were found for 1/3-asymmetric, 1/3-symmetric and 2/3 ML of H, respectively.…”

Section: Direct Dissociation Of Co In Presence Of Hydrogensupporting

confidence: 91%

Effect of Hydrogen in Adsorption and Direct Dissociation of CO on Fe (100) Surface: A DFT Study

Amaya-Roncancio¹,

Linares²,

Duarte³

et al. 2015

AJAC

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Density functional theory was employed to investigate the effect of the hydrogen in the adsorption and direct dissociation of CO on Fe (100) surface. The preadsorption of hydrogen with coverages of 0, 1/3 and 2/3 monolayer (ML) was used in the present investigation. In the case of 1/3 ML of hydrogen, two configurations of adsorption were studied. The presence of hydrogen shows a major transference of electronic density from Fe surface to CO adsorbed, increasing the adsorption energy of CO from 2.00 eV in clean surface, to 2.76 eV in 2/3 ML of hydrogen. Furthermore, the activation barrier for direct dissociation of CO was 1.13 eV and for the recombination energy 2.28 eV on clean Fe (100) surface. In the same way, the activation barrier for CO in the presence of coadsorbed hydrogen was slightly affected presenting values of 1.06 eV and 1.16 eV to 1/3 ML configurations and 0.98 eV for 2/3 ML of hydrogen. Finally, the recombination energy decreases to 1.63 eV and 1.49 eV for 1/3 ML configurations and to 1.23 eV for 2/3 ML of coadsorbed hydrogen. These results indicate that the CO adsorption and dissociation are favored in the presence of hydrogenated surfaces.

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Section: Direct Dissociation Of Co In Presence Of Hydrogensupporting

confidence: 91%

Effect of Hydrogen in Adsorption and Direct Dissociation of CO on Fe (100) Surface: A DFT Study

Amaya-Roncancio¹,

Linares²,

Duarte³

et al. 2015

AJAC

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“…33 It predicts that two, three, and four-fold coordinated CO species form the most stable binding geometry in Fe 3,4 , Fe 5 , and Fe 6 , respectively. The reported CO stretching frequencies for these species are significantly below our experimental values for CO atop bound to Fe [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] , as would be expected. Unfortunately, we were unable to measure clusters this small to confirm the transition from high coordination binding in small clusters to atop binding in large clusters, that has some parallels in rhodium cluster CO complexes.…”

Section: A Ironcontrasting

confidence: 58%

“…They are also high compared to the values calculated for atop bound CO species on extended iron surfaces at low coverage, which are in the 1880-1920 cm -1 range. [27][28][29] As the bands above 2000 cm -1 appear only at higher CO coverage on the surfaces, it might be that they are not due to isolated CO molecules but related to the presence of geminal carbonyls formed at low coordinated Fe atoms at steps or defects. Slab model calculations studying the mechanism of Fe(CO) 5 formation on Fe(100) find that geminal binding can energetically compete with the formation of isolated CO ligands.…”

Section: A Ironmentioning

confidence: 99%

Probing C–O bond activation on gas-phase transition metal clusters: Infrared multiple photon dissociation spectroscopy of Fe, Ru, Re, and W cluster CO complexes

Lyon

Gruene

Fielicke

et al. 2009

The Journal of Chemical Physics

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The binding of carbon monoxide to iron, ruthenium, rhenium, and tungsten clusters is studied by means of infrared multiple photon dissociation (IR-MPD) spectroscopy. The CO stretching mode is used to probe the interaction of the CO molecule with the metal clusters and thereby the activation of the C-O bond. CO is found to adsorb molecularly to atop positions on iron clusters. On ruthenium and rhenium clusters it also binds molecularly. In the case of ruthenium, binding is predominantly to atop sites, however higher coordinated CO binding is also observed for both metals and becomes prevalent for rhenium clusters containing more than 9 atoms. Tungsten clusters exhibit a clear size dependence for molecular vs. dissociative CO binding. This behavior denotes the crossover to the purely dissociative CO binding on the earlier transition metals such as tantalum.2

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“…26 The activation barrier of 0.77 eV obtained during this calculation is significantly lower than most of the reported barriers for different surfaces, suggesting that the Fe 55 is much more reactive toward the CO dissociation than most of the stepped and flat Fe surfaces. It seems that the ability of the metal atoms to activate reactants changes substantially as the coordination of them is reduced on both the atomic steps and the vertexes.…”

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confidence: 62%

CO Disproportionation on a Nanosized Iron Cluster

et al. 2009

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First-principles electronic structure calculations, fully incorporating the effects of spin polarization and noncollinear magnetic moments, have been used to investigate CO disproportionation on an isolated Fe cluster. After CO dissociation, which occurs on a vertex between the facets, O atoms remain on the surface while C atoms move into the cluster as the initial step toward carbide formation. The lowest CO dissociation barrier found (0.77 eV) is lower than that on most of the studied Fe surfaces. Several possible paths for CO 2 formation were identified. The lowest reaction barrier was 1.08 eV.The carbon nanotubes (CNTs) are of great interest since they exhibit unique and useful chemical and physical properties related to toughness, electrical/thermal conductivity, and magnetism.1 The chemical vapor deposition (CVD) methods are widely used as a CNTs synthesis method since they open a way to highly controlled and continuous CNT production. [2][3][4][5] In these processes, metal nanoparticles are produced in a mixed flow of carbon precursors and other gases (e.g., hydrogen), and the growth process is driven by cleaving the carbon atoms from the precursors, and these atoms will form carbon structures on the nanoparticles' surface. All properties, like diameter and chirality, of the nanotube are determined by the metal particle. In addition to the CNT synthesis, the metal nanoclusters with a size of less than 10 nm have attracted a great deal of attention due to their applications in magnetism, 6 electronics, 7 and catalysts. 8 The metal nanoparticles are widely used in several real-world catalytic applications, including the car exhaust catalysts, where reactions happen on 3-8 nm size Pt group metal particles. Often, the good catalytic activity can be related to catalytic sites, like atomic size steps, on the cluster. Due to the high curvature of the clusters, the special site density and distribution is much higher than that on almost flat surfaces. Furthermore, the real nanoclusters have several unique active sites like facets and vertexes between the facets, which can have catalytic properties that differ drastically from the ones of almost flat surfaces. The research related to the active sites is mainly limited to atomic steps, and the nanosized clusters have received much less attention.9 Experimentally, many investigators have studied metal nanostructures using a wide range of surface science techniques, but these studies were done with rather a arbitrary size of clusters because it is very difficult to prepare fixed size clusters. 9 If we want to understand the active sites on clusters, we have to know which cluster we are studying. Even then, each cluster has several different active sites, and it is very difficult to know which of them is the most active one. For this reason, the computational approach, where precise sites can be studied, is very attractive.The present study is addressing the CO disproportionation CO (g) + CO (g) h CO 2(g) + C (s) on an iron nanocluster during the CVD method for the sy...

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A DFT Study of the Adsorption and Dissociation of CO on Fe(100): Influence of Surface Coverage on the Nature of Accessible Adsorption States

Cited by 114 publications

References 29 publications

Effect of Hydrogen in Adsorption and Direct Dissociation of CO on Fe (100) Surface: A DFT Study

Effect of Hydrogen in Adsorption and Direct Dissociation of CO on Fe (100) Surface: A DFT Study

Probing C–O bond activation on gas-phase transition metal clusters: Infrared multiple photon dissociation spectroscopy of Fe, Ru, Re, and W cluster CO complexes

CO Disproportionation on a Nanosized Iron Cluster

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