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Periodic Density Functional Theory calculations reveal the potential application of 10 imidazole based N-heterocyclic carbenes (NHCs) to behave as “molecular corks” for hydrogen storage on single atom alloys, comprised of Pd/Cu(111) or Pt/Cu(111). Calculations show that functionalizing the NHC with different electron withdrawing/donating functional groups results in different binding energies of the NHC with the alloy surfaces. The results are compared to DFT calculations of carbon monoxide bound to these alloys. The Huynh electronic parameter (HEP) is calculated for several simple imidazole NHCs to gauge σ-donor ability, while Se-NMR and P-NMR calculations of selenourea derivatives and carbene-phosphinidene adducts, respectively, have been utilized to gauge π-acidity of the NHCs. It is demonstrated that consideration of both σ and π donating/accepting ability must be considered when predicting the surface-adsorbate binding energy. It was found that electron withdrawing groups tend to weaken the NHC-surface interaction while electron donating substituents tend to strengthen the interaction.
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This content will become publicly available on December 7, 2026
Tools for Understanding Molecular Orbitals Interactions of Molecules on Surfaces – Density Functional Theory Calculations of H2 Adsorbed on Cu(111) and Pd/Cu(111)
We provide a summary of contemporary computational tools utilized in the study of adsorbate interactions with solid-state materials from the perspective of a quantum chemist. This work contains a focused theoretical primer of interactions between the molecular orbitals of an adsorbate and the electronic bands of a solid as well as a review of the promising methodologies for disentangling these contributions. We apply these tools in a methodological fashion to density functional theory (DFT) calculations of molecular hydrogen (H2), H2 adsorbed to the pristine Cu(111) surface, and H2 adsorbed to a single atom alloy comprised of palladium and copper (Pd/Cu(111)) to provide chemically intuitive explanations of bonding in these systems.
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- Award ID(s):
- 2142874
- PAR ID:
- 10652154
- Publisher / Repository:
- ChemRxiv
- Date Published:
- Subject(s) / Keyword(s):
- hydrogen storage surface corking single atom alloy surface chemistry surface-adsorbate interaction energy storage
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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