Interaction of hydrogen with flat (0001) and corrugated (11–20) and (10–12) cobalt surfaces: Insights from experiment and theory

Weststrate, C.J.; Mahmoodinia, Mehdi; Farstad, Mari Helene; Svenum, Ingeborg-Helene; Strømsheim, Marie Døvre; Niemantsverdriet, J.W.; Venvik, Hilde J.

doi:10.1016/j.cattod.2019.04.002

Cited by 28 publications

(16 citation statements)

References 47 publications

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“…The most stable adsorption on the (0001) surfaces of the hcp metals Co and Ru are the hollow hcp sites. Other theoretical studies identified the fcc sites as lowest energy positions but there are no significant energy differences to the hcp sites [107,[131][132][133]. The adsorption on the bridge sites (SB or LB) for (101 ̅ 0), and (112 ̅ 0)…”

Section: Hydrogen Adsorptionmentioning

confidence: 94%

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: Hydrogen Adsorptionmentioning

confidence: 94%

Biomass hydrodeoxygenation catalysts innovation from atomistic activity predictors

Morteo-Flores

Engel

Roldán

2020

Phil. Trans. R. Soc. A.

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“…It is interesting to note that the desorption peak temperature on the open Co(11–20) surface is significantly lower than on the close-packed Co(0001) surface. This shows that CO adsorption on cobalt is not necessarily stronger on surface atoms with a lower coordination number, unlike the situation on metals such as Ru and Pt where stronger adsorption on step sites was reported. , …”

Section: Resultsmentioning

confidence: 72%

“…CO desorption spectra from Co(11−20) (10 mm diameter and 1.5 mm thickness) and Co(0001) (8 mm diameter and 2 mm thickness) single crystal surfaces were obtained using a home-built vacuum system located at Syngaschem BV, as described in detail elsewhere. 35 The samples in this setup are mounted using a U-shaped W wire, which is in thermal contact with a liquid nitrogen reservoir so that sample temperatures of around 95 K can be reached. The samples are heated by passing a direct current through the support wire.…”

Section: Methodsmentioning

confidence: 99%

“…In fact, an initially roughened surface was found to smoothen. Weststrate and co-workers 35 have established by combined temperature-programmed desorption (TPD) and theoretical investigations that, while adsorbed hydrogen atoms preferentially reside in 3-fold hollow positions on a Co(0001) terrace, the activation of the H 2 molecule is strongly enhanced by undercoordinated surface atoms as represented by steps or other terminations. These recent investigations have made progress through elaborate procedures to eliminate possible error sources (e.g., impact of impurity adsorbates and impurity carbonyl transfer).…”

Section: Introductionmentioning

confidence: 99%

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CO-Induced Surface Reconstruction of the Co(11–20) Surface—A Combined Theoretical and Experimental Investigation

et al. 2020

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The CO-induced restructuring of Co(11–20) has been investigated with temperature-programmed desorption (TPD), low-energy electron diffraction, scanning tunneling microscopy (STM), and density functional theory. CO induces a (3 × 1) surface reconstruction at room temperature, involving the anisotropic migration of Co atoms as uncovered by STM. The TPD investigations of the unreconstructed and reconstructed surface through exposure to CO at 100 K and room temperature, respectively, showed a slightly lower desorption peak temperature for the unreconstructed surface. Based on the STM observations, two theoretical model surfaces with (3 × 1) periodicity were investigated and compared to the unreconstructed surface, one with a missing and one with an added, [0001]-directed, zigzag row of Co atoms. The calculated adsorption energies infer that the added row structure is the energetically preferred surface under CO exposure. The most favorable adsorption energies were found for 4 CO coordinated to the added (topmost) row of the model surface, with the largest difference to the unreconstructed surface. Calculations of transition states yielded a significant energy barrier for removing Co from the topmost, unreconstructed layer of the hcp packing. The initial restructuring occurred preferentially through a carbonyl-type species where the migrating Co atom was bonded to two CO molecules.

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“…In this work, Pt atom is selected as the single atom site to the host surfaces (M), on the M (111), M (100) and M (110) facets, except for cobalt host surface, where only the hexagonal close-packed Co (0001) surface is considered. Indeed, the (0001) surface is the main surface orientation of Co nanoparticles with hexagonal close-packed (HCP) bulk structure [32] which have been shown to have much higher intrinsic activity than the face centered-cubic (FCC)…”

Section: Segregation Energy ( ) and Environmental Segregation Energy ( )mentioning

confidence: 99%

Mapping surface segregation of single-atom Pt dispersed in M surfaces (M = Cu, Ag, Au, Ni, Pd, Co, Rh and Ir) under hydrogen pressure at various temperatures

Wang

Zhu

Tielens

et al. 2021

Applied Surface Science

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Single-atom alloys (SAAs) are emerging materials containing isolated metal atoms dispersed on host metal surfaces, exhibiting unique reactivity compared with the corresponding monometallic counterparts. However, the stability of the isolated atoms in the host metal has hardly been studied, although, metal segregation has been commonly observed in bimetallic nanoparticles under reaction conditions. In this work we focus on single-atom Pt anchored on various metallic support surfaces. Density Functional Theory (DFT) calculations coupled with environmental segregation energy analysis are performed to map the segregation trends of 22 different Pt-SAA surfaces under various hydrogen conditions. The results show the high stability of single-atom Pt in Ni, Co, Rh and Ir host metallic surfaces while no stability is predicted on Au and Ag surfaces. For Pd and Cu host supports, the single-atom Pt is found to be stable on specific surface facets and within definite temperature and pressure conditions. This work brings an important understanding of SAA systems through the prediction of

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Interaction of hydrogen with flat (0001) and corrugated (11–20) and (10–12) cobalt surfaces: Insights from experiment and theory

Abstract: Highlights-H2 dissociation on Co is promoted by undercoordinated sites -But hydrogen atoms bind less strongly there compared to flat terrace sites -In FTS steps and kinks may be the dominant source of surface hydrogen atoms

Cited by 28 publications

References 47 publications

Biomass hydrodeoxygenation catalysts innovation from atomistic activity predictors

Biomass hydrodeoxygenation catalysts innovation from atomistic activity predictors

CO-Induced Surface Reconstruction of the Co(11–20) Surface—A Combined Theoretical and Experimental Investigation

Mapping surface segregation of single-atom Pt dispersed in M surfaces (M = Cu, Ag, Au, Ni, Pd, Co, Rh and Ir) under hydrogen pressure at various temperatures

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