Context: The interaction of norbornadiene (NBD) and norbornene (NBE) with the palladium (111) and (100) surfaces have been investigated using density functional theory (DFT). Five configurations of adsorbed NBD may be formed on Pd(111): endo-tetra-σ, endo-di-σ,π, endo-di-π, exo-di-σ, and exo-π. The NBE molecule adsorbed on Pd(111) may exist in 4 configurations: endo-di-σ, endo-π, exo-di-σ, and exo-π. On Pd(100), a smaller number adsorption configurations of NBD and NBE are formed, since the double bonds of these molecules in the endo-orientation are bound only in a di-σ mode. The adsorption energy of NBD and NBE molecules on Pd(100) is noticeably higher compared to Pd(111), which is due to the surface geometry of Pd(100). The most stable configurations on both Pd facets are endo-tetra-σ for NBD and exo-di-σ for NBE. However, due to smaller adsorption area of the exo-di-σ configuration on Pd(111), a larger number of NBD molecules may adsorbed on the same surface area. Energetically favorable endo-tetra-σ (NBD) and exo-di-σ (NBE) configurations are very mobile on Pd(111). On Pd(100), only NBE molecules can migrate, while NBD migration is hindered due to the high activation barrier.
Methods: All DFT calculations were performed using the Perdew-Burke-Ernzerhof density functional (PBE) with the relativistic SBK effective core potential and TZ2P basis set in the PRIRODA program.
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http://dx.doi.org/10.1007/s00894-023-05738-7 | DOI Listing |
Adv Mater
December 2024
Physics of Energy Conversion and Storage, Department of Physics, Technical University of Munich, James-Franck-Straße 1, 85748, Garching, Germany.
Designing electrocatalysts with optimal activity and selectivity relies on a thorough understanding of the surface structure under reaction conditions. In this study, experimental and computational approaches are combined to elucidate reconstruction processes on low-index Pd surfaces during H-insertion following proton electroreduction. While electrochemical scanning tunneling microscopy clearly reveals pronounced surface roughening and morphological changes on Pd(111), Pd(110), and Pd(100) surfaces during cyclic voltammetry, a complementary analysis using inductively coupled plasma mass spectrometry excludes Pd dissolution as the primary cause of the observed restructuring.
View Article and Find Full Text PDFJ Mol Model
October 2023
MIREA - Russian Technological University, Lomonosov Institute of Fine Chemical Technologies, 86 Vernadsky Avenue, 119571, Moscow, Russian Federation.
Context: The interaction of norbornadiene (NBD) and norbornene (NBE) with the palladium (111) and (100) surfaces have been investigated using density functional theory (DFT). Five configurations of adsorbed NBD may be formed on Pd(111): endo-tetra-σ, endo-di-σ,π, endo-di-π, exo-di-σ, and exo-π. The NBE molecule adsorbed on Pd(111) may exist in 4 configurations: endo-di-σ, endo-π, exo-di-σ, and exo-π.
View Article and Find Full Text PDFJ Phys Chem Lett
August 2023
Key Laboratory of Precision and Intelligent Chemistry, Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Equilibration dynamics of hot oxygen atoms following the dissociation of O on Pd(100) and Pd(111) surfaces are investigated by molecular dynamics simulations based on a scalable neural network potential enabling first-principles description of the interaction of O and O interacting with variable Pd supercells. By analyzing hundreds of trajectories with appropriate initial sampling, the measured distance distribution of equilibrated atom pairs on Pd(111) is well reproduced. However, our results on Pd(100) suggest that the ballistic motion of hot atoms predicted previously is a rare event under ideal conditions, while initial molecular orientation and surface thermal fluctuation could significantly affect the overall postdissociation dynamics.
View Article and Find Full Text PDFJ Am Chem Soc
June 2023
Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
Nanozymes have shown great promise in reactive oxygen species (ROS)-mediated tumor therapy with mitigated side effects but are normally limited by the complex tumor microenvironment (TME). Herein, to overcome the adverse effects of TME, such as tumor hypoxia and high endogenous glutathione (GSH), an aptamer-functionalized Pd@MoO nano-hydrangea (A-Pd@MoO NH) is constructed for high-efficiency cancer therapy. Utilizing the irregular shape characteristics of nano Pd, the A-Pd@MoO NH nanozyme simultaneously exposes catalase-like Pd(111) and oxidase-like Pd(100) surface facets as dual active centers.
View Article and Find Full Text PDFSmall
July 2022
Department of Chemical Sciences and Bernal Institute, University of Limerick, Limerick, V94 T9PX, Ireland.
The structure-activity relationship is a cornerstone topic in catalysis, which lays the foundation for the design and functionalization of catalytic materials. Of particular interest is the catalysis of the hydrogen evolution reaction (HER) by palladium (Pd), which is envisioned to play a major role in realizing a hydrogen-based economy. Interestingly, experimentalists observed excess heat generation in such systems, which became known as the debated "cold fusion" phenomenon.
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