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Density functional theory (DFT) calculations explore the stability of a single platinum atom on various flat, stepped, and defective ceria surfaces, in the context of single‐atom catalysts (SACs) for the water–gas shift (WGS) reaction. The adsorption properties and diffusion kinetics of the metal strongly depend on the support termination with large stability on metastable and stepped CeO2(100) and (210) surfaces where the diffusion of the platinum atom is hindered. At the opposite, the more stable CeO2(111) and (110) terminations weakly bind the platinum atom and can promote the growth of metallic clusters thanks to fast diffusion kinetics. The adsorption of carbon monoxide on the single platinum atom supported on the various ceria terminations is also sensitive to the surface structure. Carbon monoxide weakly binds to the single platinum atom supported on reduced CeO2(111) and (211) terminations. The desorption of the CO2 formed during the WGS reaction is thus facilitated on the latter terminations. A vibrational analysis underlines the significant changes in the calculated scaled anharmonic CO stretching frequency on these catalysts. [ABSTRACT FROM AUTHOR]

The solid electrolyte interphase (SEI) is a thin heterogeneous layer formed at the anode/electrolyte interface in lithium‐ion batteries as a consequence of the reduction of the electrolyte. The initial formation of the SEI inhibits the direct contact between the electrode and the electrolyte and thus protects the battery. However, the composition, structure, and size of the SEI evolve over time and the growth of the SEI is considered the primary mechanism leading to the gradual deterioration of the battery performance. Despite the importance of the SEI and its growth, the atomistic understanding of the underlying elementary reaction steps remains partial. Molecular modeling of the electrolyte decomposition is key to gain detailed insights that are complementary to experiments for the reactions occurring in this heterogenous interphase. In this perspective, the electron transport mechanisms are first described from the anode to the electrolyte through the SEI and highlight the importance of the inorganic/organic interface within the heterogeneous SEI: it is where the electrolyte decomposition reactions are likely to occur. Finally, a view is provided on the current progress on molecular modeling techniques (e.g., Density Functional Theory, force fields, machine learning potentials) of the SEI and the challenges each method faces. [ABSTRACT FROM AUTHOR]

Zeolites are essential materials to industry due to their adsorption and catalytic properties. The best current approach to prepare a targeted zeolite still relies on trial and error's synthetic procedures since a rational understanding of the impact of synthesis variables on the final structures is still missing. To discern the role of a variety of organic templates, we perform simulations of the early stages of condensation of silica oligomers by combining DFT, Brønsted‐Evans‐Polanyi relationships and kinetic Monte Carlo simulations. We investigate an extended reaction path mechanism including 258 equilibrium reactions and 242 chemical species up to silica octamers, comparing the computed concentrations of Si oligomers with 29SI NMR experimental data. The effect of the templating agent is linked to the modification of the intramolecular H‐bond network in the growing oligomer, which produces higher concentration of 4‐membered ring intermediates, precursors of the key double‐four ring building blocks present on more than 39 known zeolite topologies. [ABSTRACT FROM AUTHOR]

The acceptor‐less dehydrogenation of 2‐octanol was tested over cobalt supported on Al2O3, C, ZnO, ZrO2 and various TiO2 substrates. The catalysts were characterized by ICP, XRD and TGA‐H2. For Co/TiO2 P25, the effects of passivation, aging (storage at room temperature), and in situ activation under H2 were investigated. The catalysts must be tested shortly after synthesis in order to prevent deactivation. Cobalt supported on TiO2 P25 was the most active and 69 % yield of 2‐octanone was obtained, using decane as a solvent. Selectivities for 2‐octanone were observed in the range of 90 % to 99.9 %. Small amounts of C16 compounds were also formed due to aldol condensation/dehydration reactions. The catalysts exhibited higher conversion in the dehydrogenation of secondary alcohols (65‐69 %), in comparison to primary alcohols (2–10 %). The dehydrogenation of 1,2‐octanediol led to 1‐hydroxy‐2‐octanone, with a selectivity of 90 % and 69 % for Co/TiO2 P25 and Co/TiO2 P90, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Among the best‐performing homogeneous catalysts for the direct amination of activated secondary alcohols with electron‐poor amine derivatives, metal triflates, such as aluminum triflate, Al(OTf)3, stand out. Herein we report the extension of this reaction to electron‐rich amines and activated primary alcohols. We provide detailed insight into the structure and reactivity of the catalyst under working conditions in both nitromethane and toluene solvent, through experiment (cyclic voltammetry, conductimetry, NMR spectroscopy), and density functional theory (DFT) simulations. Competition between aniline and benzyl alcohol for Al in the two solvents explains the different reactivities. The catalyst structures predicted from the DFT calculations were validated by the experiments. Whereas a SN1‐type mechanism was found to be active in nitromethane, we propose a SN2 mechanism in toluene to rationalize the much higher selectivity observed when using this solvent. Also, unlike what is commonly assumed in homogeneous catalysis, we show that different active species may be active instead of only one. [ABSTRACT FROM AUTHOR]

We re-investigate the image charge model of Iori and Corni (Iori and Corni, J. Comput. Chem. 2008, 29, 1656). We find that a simple symmetrization of their model allows to obtain quantitatively correct results for the electrostatic interaction of a water molecule with a metallic surface. This symmetrization reduces the magnitude of the electrostatic interaction to less than 10% of the total interaction energy. © 2017 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

We show how the combination of Bias Exchange metadynamics (BE) with Car-Parrinello molecular dynamics (CPMD) can lead to vast improvements in the study of chemical reactions. Bias Exchange metadynamics is a recently introduced methodology that combines replica exchange techniques with the metadynamics approach. It allows fast parallel reconstruction of the free energy of a system in a virtually unlimited number of variables. The value of the method was previously demonstrated for the folding of a Triptophane cage miniprotein on the classical potential energy surface. As a test case for the DFT implementation, we investigated the competitive SN2 reaction of CH3Cl with Cl- and Br-. The results illustrate three important advantages of the method. (1) Fast and complete sampling of configuration space occurs in each replica. (2) A significant speed-up can be observed in the convergence of the free energy profiles, compared with regular metadynamics. (3) The best conformational distributions are successfully transferred from one replica to the others. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010 [ABSTRACT FROM AUTHOR]

DFT calculations, kMC method, non covalent interactions, templates, zeolite oligomerisation Keywords: DFT calculations; kMC method; non covalent interactions; templates; zeolite oligomerisation EN DFT calculations kMC method non covalent interactions templates zeolite oligomerisation 7524 7524 1 03/23/21 20210322 NES 210322 B DFT- und kMC-Rechnungen b werden kombiniert, um die Reaktionsenergieprofile und die Bildungskinetik von Silika-Oligomeren zu untersuchen, wie Caroline Mellot-Draznieks, Carlos Nieto-Draghi et al. in ihrem Forschungsartikel auf S. 7187 beschreiben. Rücktitelbild: Impact of Organic Templates on the Selective Formation of Zeolite Oligomers (Angew. [Extracted from the article]

Back Cover: Impact of Organic Templates on the Selective Formation of Zeolite Oligomers (Angew. DFT calculations, kMC method, non covalent interactions, templates, zeolite oligomerisation Keywords: DFT calculations; kMC method; non covalent interactions; templates; zeolite oligomerisation EN DFT calculations kMC method non covalent interactions templates zeolite oligomerisation 7448 7448 1 03/19/21 20210322 NES 210322 B DFT and kMC calculations b were combined to investigate the impact of the most commonly used organic template molecules both on the reaction energy profiles and the kinetics of formation of silica oligomers, as described by Caroline Mellot-Draznieks, Carlos Nieto-Draghi, and co-workers in their Research Article on page 7111. [Extracted from the article]