The Influence of Ni Addition in the Mechanism of CO Electroreduction on Cu Crystals-Mechanistic Insight from DFT Simulations.

We present a DFT analysis of the role of the Cu-Ni synergistic effect for the CO reduction to CH, in comparison to the pure Cu catalyst. The analysis is focused on the thermodynamic stability of reactive intermediates along the proposed pathway of C species formation. We have observed that the potential needed for the reaction decreases with the addition of Ni in the investigated model.

Reactive Grand-Canonical Monte Carlo Simulations for Modeling Hydration of MgCl.

Thermochemical heat-storage applications, based on the reversible endo-/exothermic hydration reaction of salts, are intensively investigated to search for compact heat-storage devices. To achieve a truly valuable storage system, progressively complex salts are investigated. For these salts, the equilibrium temperature and pressure conditions are not always easy to predict.

Gibbs Ensemble Monte Carlo for Reactive Force Fields to Determine the Vapor-Liquid Equilibrium of CO and HO.

Absorption and reactive properties of fluids in porous media are key to the design and improvement of numerous energy related applications. Molecular simulations of these systems require accurate force fields that capture the involved chemical reactions and have the ability to describe the vapor-liquid equilibrium (VLE). Two new reactive force fields (ReaxFF) for CO and HO are developed, which are capable of not only modeling bond breaking and formation in reactive environments but also predicting their VLEs at saturation conditions.

Absolute energy level positions in tin- and lead-based halide perovskites.

Metal halide perovskites are promising materials for future optoelectronic applications. One intriguing property, important for many applications, is the tunability of the band gap via compositional engineering. While experimental reports on changes in absorption or photoluminescence show rather good agreement for different compounds, the physical origins of these changes, namely the variations in valence and conduction band positions, are not well characterized.

Correlations between Density-Based Bond Orders and Orbital-Based Bond Energies for Chemical Bonding Analysis.

Quantum chemistry-based codes and methods provide valuable computational tools to estimate reaction energetics and elucidate reaction mechanisms. Electronic structure methods allow directly studying the chemical transformations in molecular systems involving breaking and making of chemical bonds and the associated changes in the electronic structure. The link between the electronic structure and chemical bonding can be provided through the crystal orbital Hamilton population (COHP) analysis that allows quantifying the bond strength by computing Hamilton-weighted populations of localized atomic orbitals.

Mechanistic Insight into the [4 + 2] Diels-Alder Cycloaddition over First Row d-Block Cation-Exchanged Faujasites.

The Diels-Alder cycloaddition (DAC) is a powerful tool to construct C-C bonds. The DAC reaction can be accelerated in several ways, one of which is reactant confinement as observed in supramolecular complexes and Diels-Alderases. Another method is altering the frontier molecular orbitals (FMOs) of the reactants by using homogeneous transition-metal complexes whose active sites exhibit d-orbitals suitable for net-bonding orbital interactions with the substrates.

Tin, The Enabler-Hydrogen Diffusion into Ruthenium.

Hydrogen interaction with ruthenium is of particular importance for the ruthenium-capped multilayer reflectors used in extreme ultraviolet (EUV) lithography. Hydrogen causes blistering, which leads to a loss of reflectivity. This problem is aggravated by tin.

Electronic Structure Analysis of the Diels-Alder Cycloaddition Catalyzed by Alkali-Exchanged Faujasites.

The Diels-Alder cycloaddition (DAC) reaction is a commonly employed reaction for the formation of C-C bonds. DAC catalysis can be achieved by using Lewis acids and via reactant confinement in aqueous nanocages. Low-silica alkali-exchanged faujasite catalysts combine these two factors in one material.

An Active Alkali-Exchanged Faujasite Catalyst for -Xylene Production via the One-Pot Diels-Alder Cycloaddition/Dehydration Reaction of 2,5-Dimethylfuran with Ethylene.

The one-pot Diels-Alder cycloaddition (DAC)/dehydration (D) tandem reaction between 2,5-dimethylfuran and ethylene is a potent pathway toward biomass-derived -xylene. In this work, we present a cheap and active low-silica potassium-exchanged faujasite (KY, Si/Al = 2.6) catalyst.

Elucidation of the origin of chiral amplification in discrete molecular polyhedra.

Chiral amplification in molecular self-assembly has profound impact on the recognition and separation of chiroptical materials, biomolecules, and pharmaceuticals. An understanding of how to control this phenomenon is nonetheless restricted by the structural complexity in multicomponent self-assembling systems. Here, we create chiral octahedra incorporating a combination of chiral and achiral vertices and show that their discrete nature makes these octahedra an ideal platform for in-depth investigation of chiral transfer.

Scaling Relations for Acidity and Reactivity of Zeolites.

Zeolites are widely applied as solid acid catalysts in various technological processes. In this work we have computationally investigated how catalytic reactivity scales with acidity for a range of zeolites with different topologies and chemical compositions. We found that straightforward correlations are limited to zeolites with the same topology.

Photoisomerization induced scission of rod-like micelles unravelled with multiscale modeling.

Hypothesis: In photorheological fluids, subtle molecular changes caused by light lead to abrupt macroscopic alterations. Upon UV irradiation of an aqueous cetyltrimethylammonium bromide (CTAB) and trans-ortho-methoxycinnamic acid (trans-OMCA) solution, for instance, the viscosity drops over orders of magnitude. Multiscale modeling allows to elucidate the mechanisms behind these photorheological effects.

Role of Adsorbed Water on Charge Carrier Dynamics in Photoexcited TiO.

Overall photocatalytic water splitting is one of the most sought after processes for sustainable solar-to-chemical energy conversion. The efficiency of this process strongly depends on charge carrier recombination and interaction with surface adsorbates at different time scales. Here, we investigated how hydration of TiO P25 affects dynamics of photogenerated electrons at the millisecond to minute time scale characteristic for chemical reactions.

Structure of palladium nanoparticles under oxidative conditions.

Using density functional theory (DFT) and thermodynamic considerations we study the shape and stability of Pd nanoparticles in oxygen-lean and oxygen-rich atmospheres. We find that at very high oxygen coverage cubes exposing (100) faces will form, which are stabilized due to the formation of a O/(√5 × √5)R27° overlayer. The shape of oxygen-covered Pd and Pt nanoparticles is compared in this study.

Unraveling the self-assembly of the (S)-glutamic acid "flower" structure on Ag(100).

(S)-Glutamic acid adsorbed on Ag(100) organizes in different self-assembled structures depending on surface temperature [Smerieri, M.; Vattuone, L.; Kravchuk, T.