Adsorption, Desorption, and Dissociation of CO on Tungsten(100), a DFT Study

Scheijen, F.J.E.; Niemantsverdriet, J.W.; Curulla‐Ferré, Daniel

doi:10.1021/jp711995d

Cited by 13 publications

(8 citation statements)

References 73 publications

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Section: Oxygen Adsorptionsupporting

confidence: 93%

“…On the bcc(100) surfaces, the adsorption of oxygen occurs preferentially on the hollow sites of Fe(100) and on the bridge sites of Mo(100) and W(100). This is in agreement with previous computational studies [148][149][150][151]. The hollow sites were identified as the most stable positions for oxygen adsorption on the (110) surfaces of Fe and W while the long bridge position is most favourable on Mo (110).…”

Section: (E) Oxygen Adsorptionsupporting

confidence: 92%

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Biomass hydrodeoxygenation catalysts innovation from atomistic activity predictors

Morteo-Flores

Engel

Roldán

2020

Phil. Trans. R. Soc. A.

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Circular economy emphasizes the idea of transforming products involving economic growth and improving the ecological system to reduce the negative consequences caused by the excessive use of raw materials. This can be achieved with the use of second-generation biomass that converts industrial and agricultural wastes into bulk chemicals. The use of catalytic processes is essential to achieve a viable upgrade of biofuels from the lignocellulosic biomass. We carried out density functional theory calculations to explore the relationship between 13 transition metals (TMs) properties, as catalysts, and their affinity for hydrogen and oxygen, as key species in the valourization of biomass. The relation of these parameters will define the trends of the hydrodeoxygenation (HDO) process on biomass-derived compounds. We found the hydrogen and oxygen adsorption energies in the most stable site have a linear relation with electronic properties of these metals that will rationalize the surface's ability to bind the biomass-derived compounds and break the C–O bonds. This will accelerate the catalyst innovation for low temperature and efficient HDO processes on biomass derivates, e.g. guaiacol and anisole, among others. Among the monometallic catalysts explored, the scaling relationship pointed out that Ni has a promising balance between hydrogen and oxygen affinities according to the d -band centre and d -band width models. The comparison of the calculated descriptors to the adsorption strength of guaiacol on the investigated surfaces indicates that the d -band properties alone are not best suited to describe the trend. Instead, we found that a linear combination of work function and d -band properties gives significantly better correlation. This article is part of a discussion meeting issue ‘Science to enable the circular economy’.

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Section: Oxygen Adsorptionsupporting

confidence: 93%

Section: (E) Oxygen Adsorptionsupporting

confidence: 92%

Biomass hydrodeoxygenation catalysts innovation from atomistic activity predictors

Morteo-Flores

Engel

Roldán

2020

Phil. Trans. R. Soc. A.

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“…Following the previous strategy, , calculations have been done at 0.25 and 0.5 ML to account for the coverage effects on the structural parameters, vibrational frequencies, activation energy of dissociation, and reaction energy. Results are displayed in Tables and .…”

Section: Resultsmentioning

confidence: 99%

Adsorption and Dissociation of CO on Body-Centered Cubic Transition Metals and Alloys: Effect of Coverage and Scaling Relations

2009

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The adsorption and dissociation of CO have been calculated on the (100) surfaces of the body-centered cubic transition metals Fe, Mo, Cr, and W and the alloys Fe3Mo and Fe3Cr using density functional theory for two CO coverages, 0.25 and 0.5 ML. A complete analysis of the vibrational frequencies was performed to check whether the calculated structures are stable geometries or transition-state structures. For coverages up to 0.25 ML, carbon monoxide adsorbs molecularly onto all four metals at fourfold hollow sites with tilting angles with respect to the surface normal of 47°, 57°, 57°, and 58° and adsorption energies of −1.53, −2.64, −3.03, and −3.01 eV for Fe, Mo, Cr, and W, respectively. The calculated CO stretching frequencies at this coverage are 1211, 1062, 1037, and 926 cm−1. At higher coverages, CO adsorption does not exhibit significant changes in both adsorption energy and tilting angle on all four metals but leads to blue shifts of the CO frequency for Fe and Cr and red shifts for Mo and W. Furthermore, scaling relations apply to a bent CO species at a surface coverage of 0.25 ML of CO on all four transition metals as well as the metal alloys Fe3Mo and Fe3Cr, in the sense that the heat of adsorption of CO and the activation energy of CO dissociation scale linearly with the heat of adsorption of the carbon as well as both dissociation products.

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“…Seemingly, bcc metals such as Fe, Cr, Mo, and W have similar ability to capture the unique CO species. However, Cr(100), Mo(100), and W(100) are well-known examples in which CO molecules are prone to dissociation at low temperatures. − We can hardly find the precursor state of molecular CO on these bcc(100) surfaces as the surface temperature approaches 300 K. Thus, the Fe(100) turns out to be the only transition metal surface that can capture “lying-down” molecular CO at room temperatures. Interestingly, experiments and DFT calculations consistently showed that the unique CO species preferentially occupies the surface hollow sites − with considerably inclined molecular orientations, resulting in a configuration where the carbon and oxygen atoms occupied the hollow and bridge sites, respectively (it is referred to as Hb) (Figure ).…”

Section: Introductionmentioning

confidence: 99%

Chemical Bonding of Unique CO on Fe(100)

Peng

et al. 2018

J. Phys. Chem. C

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At low coverage, CO molecules are known to preferentially occupy the hollow sites of Fe(100) with considerably inclined molecular orientations. This CO configuration serves as the precursor state of CO dissociation, which is particularly important in several important catalytic reactions. In this study, we present a unique bonding picture of the precursor state from the spin, charge, and orbital perspectives. From the spin and orbital views, we show the antiferromagenetic nature of the adsorbate−metal coupling, where 2π magnetism prevails with a dominant spin-down channel. However, contrasting tendencies are found for the two 1π orbitals in two orthogonal directions: the 1π orbital in the vertical plane loses its symmetry, whereas the other 1π orbital remains intact with a preserved symmetry. The 1π symmetry in the vertical plane favors the 1π → 2π* excitation mechanism owing to the partial opening up of the 1π symmetry. In the charge perspective, we have identified a charge transfer mechanism involving the local structural I Fe C −C−O motif, in which the surface slightly charges the adsorbate with additional partial electrons located at the surface Fe atoms bonded to the carbon end, whereas the charges of the metallic atoms beneath the I Fe C −C−O motif are found to be depleted. In both the adsorbate and metal sides, the depletion of s electrons serves as a good measure of orbital repulsion and delocalization. Interestingly, the carbon and oxygen ends exhibit contrasting electron affinity with the metal surface: the carbon end is attractive, whereas the oxygen end is repulsive in terms of the contrasting charge rearrangement in the bonded metallic atoms.

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Adsorption, Desorption, and Dissociation of CO on Tungsten(100), a DFT Study

Cited by 13 publications

References 73 publications

Biomass hydrodeoxygenation catalysts innovation from atomistic activity predictors

Biomass hydrodeoxygenation catalysts innovation from atomistic activity predictors

Adsorption and Dissociation of CO on Body-Centered Cubic Transition Metals and Alloys: Effect of Coverage and Scaling Relations

Chemical Bonding of Unique CO on Fe(100)

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