The Electronic Structure and Bonding of Acetylene on PdGa(110)

Bechthold, P.; Sandoval, Mario G.; Gonzalez, Estela Andrea; Brizuela, G.; Bonivardi, Adrian Lionel; Jasen, Paula Verónica

doi:10.1021/acs.jpcc.5b04214

Cited by 16 publications

(9 citation statements)

References 52 publications

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“…Although there are studies available for reaction mechanisms on the different (111), (1̅1̅1̅), and (210) surfaces, we find that there is hardly any available on the (100) and (110) surfaces. To the best of our knowledge, the only study of acetylene hydrogenation on the (110) surface was reported by Bechthold and co-workers . However, from our previous study we find that the surface termination on which they have done their studies is thermodynamically unfavorable.…”

Section: Introductionmentioning

confidence: 62%

“…To determine the hydrogenation mechanism and the associated barriers, and thereby understand the reactivity and the selectivity of these model catalysts, we have studied the reaction pathways on these surfaces. Since it has already been shown that coke formation have large barriers (about 6.5 eV) on the PdGa surfaces, we have not considered this in our reaction pathway studies. Unlike Pd(111) where hydrogen dissociates spontaneously, , on the PdGa surfaces hydrogen dissociation is an activated process .…”

Section: Results and Discussionmentioning

confidence: 99%

“…To the best of our knowledge, the only study of acetylene hydrogenation on the (110) surface was reported by Bechthold and co-workers. 20 However, from our previous study we find that the surface termination on which they have done their studies is thermodynamically unfavorable. We also note that based on simulation cleavage experiments by Krajcȋ ́and Hafner, the (100) surfaces are the most exposed ones over a wide range of Ga chemical potential.…”

Section: Introductionmentioning

confidence: 93%

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Selectivity and Reactivity of Pd-Rich PdGa Surfaces toward Selective Hydrogenation of Acetylene: Interplay of Surface Roughness and Ensemble Effect

Kumar

Ghosh

2016

J. Phys. Chem. C

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Recent experiments have shown that PdGa nanocrystallites act as highly selective and reactive catalyst for selective hydrogenation of acetylene to ethylene. Motivated by these experimental results we have studied the mechanism and energetics of the above reaction on low indexed (100) and (110) PdGa surfaces using first-principles density functional theory based calculations. We find that the energetically favorable (100) surface created by cleaving the crystal in the less dense region shows reasonably good selectivity and high reactivity. The reactivity on this surface is comparable to that observed on Pd(111) surfaces. Since this surface termination is stable over a wide range of Ga chemical potential and hence is likely to occupy a substantial fraction of the surface area of PdGa nanocrystallites, we suggest this termination is responsible for the selectivity and reactivity exhibited by PdGa. In contrast to other surfaces where hydrogen adsorption and dissociation is followed by acetylene adsorption and hydrogenation, on this surface we identify a novel reaction mechanism in which hydrogen dissociation occurs in the presence of acetylene. A careful analysis of the factors determining the selectivity shows that selectivity results due to an interplay between surface roughness and chemical nature of the reactive ensemble.

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Section: Introductionmentioning

confidence: 62%

Section: Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 93%

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Selectivity and Reactivity of Pd-Rich PdGa Surfaces toward Selective Hydrogenation of Acetylene: Interplay of Surface Roughness and Ensemble Effect

Kumar

Ghosh

2016

J. Phys. Chem. C

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“…Driven by the availability of single crystals of many materials [60][61][62], further understanding is established in semi-hydrogenation reactions by surface science studies [63][64][65][66][67]. With the aid of atomically resolved scanning tunnelling microscopy, the surface structure can be revealed ( Figure 6) which then forms the basis for reliable quantum chemical calculations [68][69][70][71]. While covalent bonding in intermetallic compounds can stabilise bulk-terminated surface structures this is no necessity.…”

Section: Deep Understandingmentioning

confidence: 99%

Intermetallic compounds in catalysis – a versatile class of materials meets interesting challenges

Armbrüster

2020

Science and Technology of Advanced Materials

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The large and vivid field of intermetallic compounds in catalysis is reviewed to identify necessities, strategies and new developments making use of the advantageous catalytic properties of intermetallic compounds. Since recent reviews summarizing contributions in heterogeneous catalysis as well as electrocatalysis are available, this contribution is not aiming at a comprehensive literature review. To introduce the field, first the interesting nature of intermetallic compounds is elaboratedincluding possibilities as well as requirements to address catalytic questions. Subsequently, this review focuses on exciting developments and example success stories of intermetallic compounds in catalysis. Since many of these are based on recent advances in synthesis, a short overview of synthesis and characterisation is included. Thus, this contribution aims to be an introduction to the newcomer as well as being helpful to the experienced researcher by summarising the different approaches. Selected examples from literature are chosen to illustrate the versatility of intermetallic compounds in heterogeneous catalysis where the emphasis is on developments since the last comprehensive review in the field.

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“…Our analysis also demonstrates that the gallium atoms in PdGa are not simply acting as a "spacers": they actively affect the adsorption energies of carbon-based molecules, as was recently pointed out by Bechthold and coworkers. 54…”

Section: Origin Of the High Enantioselectivitymentioning

confidence: 99%

Hidden Beneath the Surface: Origin of the Observed Enantioselective Adsorption on PdGa(111)

et al. 2018

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We unravel the origin of the recently observed striking enantioselectivity of the PdGa(111) surface with respect to the adsorption of a small organic molecule, 9-ethynylphenanthrene, using first-principles calculations. It turns out that the key ingredient to understand the experimental evidence is the appropriate description of van der Waals interactions beyond the widely employed atomic pairwise approximation. A recently developed van der Waals-inclusive density functional method, which encompasses dielectric screening effects, reveals the origin of the experimentally observed enantioselectivity and provides conclusive evidence of chiral recognition on a bimetallic surface driven by dispersion interactions. The incorporation of dielectric screening leads to a renormalization of the dispersion interaction range, allowing for the appropriate weighting of the molecule-substrate interactions at intermediate distances between 2.5 and 5 Å. Our findings have implications for the structure and stability of complex organic/inorganic systems where dielectric screening effects are expected to be of general importance.

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The Electronic Structure and Bonding of Acetylene on PdGa(110)

Cited by 16 publications

References 52 publications

Selectivity and Reactivity of Pd-Rich PdGa Surfaces toward Selective Hydrogenation of Acetylene: Interplay of Surface Roughness and Ensemble Effect

Selectivity and Reactivity of Pd-Rich PdGa Surfaces toward Selective Hydrogenation of Acetylene: Interplay of Surface Roughness and Ensemble Effect

Intermetallic compounds in catalysis – a versatile class of materials meets interesting challenges

Hidden Beneath the Surface: Origin of the Observed Enantioselective Adsorption on PdGa(111)

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