H<sub>2</sub>dissociation on individual Pd atoms deposited on Cu(111)

Ramos, M.; Mártínez, A E; Busnengo, H. F.

doi:10.1039/c1cp22163a

Cited by 45 publications

(80 citation statements)

References 43 publications

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“…3 are in very good agreement with recent DFT-PBE MD calculations reported by Ramos et al By performing DFT-PBE calculations for a (3×3) Pd-Cu(111) alloy (which corresponds to a Pd coverage of 11%), they found an activation energy barrier for H 2 dissociation of 0.25 eV [25]. This barrier was found to decrease slightly to 0.20 eV when similar calculations were performed for a (2×2) PdCu(111) structure (corresponding to a Pd coverage of 25%).…”

Section: Resultssupporting

confidence: 90%

“…Using a different argument (based on the exposure/coverage ratio) a similar figure has been estimated in Ref. [25]. This value is roughly one order of magnitude larger than the one measured in our current work.…”

Section: Resultssupporting

confidence: 87%

“…The latter is in excellent agreement with the DFT-MD calculations reported by Ramos et al [25], which gives further support to the calculated PES barriers.…”

Section: Introductionsupporting

confidence: 91%

“…In addition, by performing DFT molecular dynamics (DFT-MD) calculations including the six degrees of freedom of the potential energy surface (PES), Ramos et al were able to estimate the H 2 initial sticking probability on individual isolated Pd atoms deposited on Cu(111). For E i ∼ 0.15 − 0.20 eV and 1% Pd, this value was found to be 6 × 10 −4 , increasing to 7 × 10 −3 for a Pd coverage of 11% [25]. We have recently shown that diffraction of H 2 is a very useful technique to characterize the corresponding PES for hydrogen dissociative chemisorption at metal surfaces [26].…”

Section: Introductionmentioning

confidence: 98%

“…This very low barrier for the Pd-Cu(111) system is consistent with the high reactivity observed in their STM experiments [12], which requires a relative large value for the H 2 initial sticking probability. However, in a recent study based on Density Functional Theory (DFT) calculations, Ramos and coworkers have found that the activation barrier for H 2 dissociation on the Pd-Cu(111) system is 0.25 eV [25], i. e. one order of magnitude larger than the one reported by Sykes et al In particular, these calculations showed that the large increase of the reactivity observed in experiment is mainly due to the reduction of the minimum activation energy barrier for dissociation from 0.63 eV on pure Cu(111) [24] to ∼ 0.25 eV on the Pd-Cu(111) system. In addition, by performing DFT molecular dynamics (DFT-MD) calculations including the six degrees of freedom of the potential energy surface (PES), Ramos et al were able to estimate the H 2 initial sticking probability on individual isolated Pd atoms deposited on Cu(111).…”

Section: Introductionmentioning

confidence: 99%

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Initial Sticking Coefficient of H2 on the Pd–Cu(111) Surface Alloy at very Low Coverages

Farı́as

Minniti

Taleb

et al. 2013

Zeitschrift Für Physikalische Chemie

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Surface Alloys / Hydrogen Dissociation / ReactivityWe present an experimental study of the initial dissociative sticking probability of H 2 on the PdCu(111) surface alloy at Pd coverages between 1-10%. The measurements have been performed using a supersonic molecular beam with an incident energy range E i = 75-163 meV. In agreement with a recent STM study, our results confirm that small amounts of Pd atoms significantly increase the reactivity of the inert Cu(111) surface, although the measured initial sticking probability values were found to be much lower than the ones estimated from the STM work. For a Pd coverage of 1% and E i ∼ 0.10 eV, the H 2 initial sticking probability was found to be 2 × 10 −3 , increasing to 4 × 10 −3 for a Pd coverage of 10%. This agrees well with a recent molecular dynamics study, in which the initial sticking probability was estimated in 7 × 10 −3 for a Pd coverage of 11% and E i ∼ 0.15-0.20 eV. Essentially the same values were measured in the whole incident energy range investigated. Therefore, our results support the main conclusion of the molecular dynamics calculations about the mechanism leading to the increase of reactivity of the Pd-Cu(111) surface alloy, which combines a lower activation energy barrier for dissociation of ∼ 0.25 eV on top of substitutional Pd atoms with spillover onto the Cu(111) surface.

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Section: Resultssupporting

confidence: 90%

Section: Resultssupporting

confidence: 87%

“…The latter is in excellent agreement with the DFT-MD calculations reported by Ramos et al [25], which gives further support to the calculated PES barriers.…”

Section: Introductionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Initial Sticking Coefficient of H2 on the Pd–Cu(111) Surface Alloy at very Low Coverages

Farı́as

Minniti

Taleb

et al. 2013

Zeitschrift Für Physikalische Chemie

View full text Add to dashboard Cite

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Sustained Hydrogen Spillover on Pt/Cu(111) Single‐Atom Alloy: Dynamic Insights into Gas‐Induced Chemical Processes

Gu,

Lin

2023

Angewandte Chemie

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Hydrogen spillover, involving the surface migration of dissociated hydrogen atoms from active metal sites to the relatively inert catalyst support, plays a crucial role in hydrogen‐involved catalytic processes. However, a comprehensive understanding of how H atoms are driven to spill over from active sites onto the catalyst support is still lacking. Here, we examine the atomic‐scale perspective of the H spillover process on a Pt/Cu(111) single atom alloy surface using machine‐learning accelerated molecular dynamics calculations based on density functional theory. Our results show that when an impinging H2 dissociates at an active Pt site, the Pt atom undergoes deactivation due to the dissociated hydrogen atoms that attach to it. Interestingly, collisions between H2 and sticking H atoms facilitate H spillover onto the host Cu, leading to the reactivation of the Pt atom and the realization of a continuous H spillover process. This work underscores the importance of the interaction between gas molecules and adsorbates as a driving force in elucidating chemical processes under a gaseous atmosphere, which has so far been underappreciated in thermodynamic studies.

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Deciphering the Factors Controlling Hydrogen and Methyl Spillover upon Methane Dissociation on Rh/Cu(111) Single‐Atom Alloy

Gu,

Guo,

Lin

2024

Angewandte Chemie

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Spillover of adsorbed species from one active site to another is a key step in heterogeneous catalysis. However, the factors controlling this step, particularly the spillover of polyatomic species, have rarely been studied. Herein, we investigate the spillover dynamics of H* and CH3* species on a single‐atom alloy surface (Rh/Cu(111)) upon the dissociative chemisorption of methane (CH4), using molecular dynamics that considers both surface phonons and electron‐hole pairs. These dynamical calculations are made possible by a high‐dimensional potential energy surface machine learned from density functional theory data. Our results provide compelling evidence that the H* and CH3* can spill over on the metal surface at experimental temperatures and reveal novel dynamical features involving an internal motion during diffusion for CH3*. Increasing surface temperature has minor effect on promoting spillover, as geminate recombinative desorption becomes more prevalent. However, the poisoning of the active site can be mitigated by frequent gaseous molecular collisions that occur under ambient pressure in real‐world catalysis, which transfer energy to the trapped adsorbates. Interestingly, the bulky CH3* exhibits a significant spillover advantage over the light H* due to its larger size, which facilitates energy acquisition. These insights help to advance our understanding of spillover in heterogeneous catalysis.

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H₂dissociation on individual Pd atoms deposited on Cu(111)

Cited by 45 publications

References 43 publications

Initial Sticking Coefficient of H2 on the Pd–Cu(111) Surface Alloy at very Low Coverages

Initial Sticking Coefficient of H2 on the Pd–Cu(111) Surface Alloy at very Low Coverages

Sustained Hydrogen Spillover on Pt/Cu(111) Single‐Atom Alloy: Dynamic Insights into Gas‐Induced Chemical Processes

Deciphering the Factors Controlling Hydrogen and Methyl Spillover upon Methane Dissociation on Rh/Cu(111) Single‐Atom Alloy

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H2dissociation on individual Pd atoms deposited on Cu(111)

Cited by 45 publications

References 43 publications

Initial Sticking Coefficient of H2 on the Pd–Cu(111) Surface Alloy at very Low Coverages

Initial Sticking Coefficient of H2 on the Pd–Cu(111) Surface Alloy at very Low Coverages

Sustained Hydrogen Spillover on Pt/Cu(111) Single‐Atom Alloy: Dynamic Insights into Gas‐Induced Chemical Processes

Deciphering the Factors Controlling Hydrogen and Methyl Spillover upon Methane Dissociation on Rh/Cu(111) Single‐Atom Alloy

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H₂dissociation on individual Pd atoms deposited on Cu(111)