Colloidal organometallic synthesis of solution-processable barium titanate nanoparticles for nanoelectronic applications.

Perovskite oxides like barium titanate (BaTiO) exhibit desirable properties: notably high dielectric constants, piezoelectricity, and ferroelectricity, thereby enabling more advanced electronic devices and actuators. There are numerous synthesis procedures for BaTiO, among which, nanoparticle syntheses are versatile and well-studied. However, colloidal organometallic synthesis is less commonly employed for this material despite offering processing advantages like facile compositional control and customizable surface chemistry.

On the Design of the Metal-Support Interface in Methanol Electrocatalytic Oxidation.

In this work, we present a theoretical investigation of the SrTiO perovskite-supported Pd catalyst in the methanol electro-oxidation reaction. In order to determine the metal-support interactions, we designed a system consisting of a Pd (100) double layer supported on one of the two possible terminations of the (100) perovskite surface. These terminations are characterized by different reducibilities of the layers directly interacting with the Pd bilayer and result in the difference in the stability of the surface-bound intermediates.

Partial Methane Oxidation to Methanol on Ru-Porphyrins - on the Role of Non-Innocent Ligands and Spin Crossover.

The partial oxidation reaction of CH led to the formation of CH OH in the presence of Ru-porphyrin oxo complexes (denoted as POR, POR-O and POR-OH where in the case of the last two, oxygen atom and the OH group were attached to the active site, respectively), in which Ru was present on different oxidation states. The simulations were performed based on Density Functional Theory (DFT) with extended geometric and electronic structure analyses of each reaction step. Moreover, the reaction pathways were investigated in different spin states.

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.

Effect of Newly Synthesized Structures of Peptides on the Stability of the Monolayers Formed.

The aim of the study was to evaluate the effect of the peptide structure (WKWK)-KWKWK-NH, P4 (C12)-KKKK-NH, P5 (KWK)-KWWW-NH, P6 (KK)-KWWW-NH on their physicochemical properties. The thermogravimetric method (TG/DTG) was used, which made it possible to observe the course of chemical reactions and phase transformations occurring during the heating of solid samples. Based on the DSC curves, the enthalpy of the processes occurring in the peptides was determined.

Assessment of the Influence of the Selected Range of Visible Light Radiation on the Durability of the Gel with Ascorbic Acid and Its Derivative.

(1) Background: Depending on the type of hydrophilic polymer used, different types of hydrogels may be chemically stable or may degrade and eventually disintegrate, or dissolve upon exposure to sunlight. Many over-the-counter medications are now stored with a limited control of temperature, humidity and lighting. Therefore, in this study, the photostability of a gel made of cross-linked polyacrylic acid (PA), methylcellulose (MC) and aristoflex (AV) was assessed, and the interaction between the polymers used and ascorbic acid and its ethylated derivative was investigated.

Effect of a Support on the Properties of Zinc Oxide Based Sorbents.

We present the comparative analysis of three Zn-based sorbents for the process of sulphur removal from hot coal gas. The sorbents were prepared by a slurry impregnation of TiO, SiO and AlO, resulting in complex, multiphase materials, with the dominant phases of ZnTiO, ZnSiO and ZnAlO, respectively. We have analyzed the effect of supports on the phase composition, texture, reducibility and HS sorption.

Mixing ReaxFF parameters for transition metal oxides using force-matching method.

We present the development of the method for the refitting the ReaxFF parameters for a system consisting of the mixed transition metal oxides. We have tested several methods allowing to calculate the differences between the vectors of the forces acting on atoms obtained from the reference DFT simulation and the parameters-dependent ReaxFF. We conclude that the footrule method yields the best parameters among the investigated options.

Sensitivity of Intra- and Intermolecular Interactions of Benzo[h]quinoline from Car-Parrinello Molecular Dynamics and Electronic Structure Inspection.

The O-H...

The pathways of the CO hydrogenation by NiCu/ZnO from DFT molecular dynamics simulations.

Metal nanoparticles supported on semiconductor surfaces have been proposed as promising nanocatalyst candidates of CO conversion to energy carrier molecules such as formic acid or carbon monoxide, which can be used as a feedstock for fuels synthesis. This study is focused on the bimetallic Cu/Ni nanoparticles supported on the ZnO. The respective reaction mechanisms have been studied by means of the Molecular Dynamics with the DFT methodology.

Helping Thy Neighbor: How Cobalt Doping Alters the Electrocatalytic Properties of Hematite.

We present analysis of the indirect role of Co doping on the electrocatalytic activity of α-FeO. Upon substitution of one of the Fe atoms in the hematite surface, we observed a promoting effect of the substitution, upon which the overpotential required for the water-splitting reaction decreased in all substitution sites investigated. The cobalt site itself, however, does not exhibit the improved properties with respect to the undoped hematite.

Aminophosphonates and aminophosphonic acids with tetrasubstituted stereogenic center: diastereoselective synthesis from cyclic ketimines.

New chiral tetrasubstituted aminophosphonic acid derivatives of hexahydroquinoxalin-2(1H)-one were synthesised via highly diastereoselective hydrophosphonylation of the corresponding imines with tris(trimethylsilyl) phosphite as phosphorus nucleophile. High asymmetric induction, good yields, mild reaction conditions, and ease of purification of the final products are the key advantages of the presented protocol.

Insight into the Formation of Nanostructured MFI Sheets and MEL Needles Driven by Molecular Recognition.

Mesoporous and nanostructured zeolite-based catalysts experience prolonged lifetimes due to increased mass transfer and reduced micropore obstruction by coke formation as compared to their bulky microporous counterparts. Diquaternary ammonium structure-directing agents (SDAs) can be used to synthesize hierarchical MFI sheet-like and MEL needle-like zeolites. An explanation of the underlying molecular-level details of the synthesis of these nanostructured zeolites is presented on the basis of non-covalent interactions between the template and zeolite surfaces as well as silicate oligomers studied by means of classical molecular dynamics.

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.

Establishing hierarchy: the chain of events leading to the formation of silicalite-1 nanosheets.

In applying a multi-scale spectroscopic and computational approach, we demonstrate that the synthesis of stacked zeolite silicalite-1 nanosheets, in the presence of a long-tail diquaternary ammonium salt surfactant, proceeds through a pre-organised phase in the condensed state. small-angle X-ray scattering, coupled to paracrystalline theory, and backed by electron microscopy, shows that this phase establishes its meso-scale order within the first five hours of hydrothermal synthesis. vibrational and solid-state NMR spectroscopy reveal that this meso-shaped architecture already contains some elementary zeolitic features.

The Properties and Activity of TiO /beta-SiC Nanocomposites in Organic Dyes Photodegradation.

The TiO /beta-SiC nanocomposites containing 0-25 wt. % of beta-SiC were synthesized by the sol-gel method and tested in the photodegradation of methylene blue and methyl orange water solutions. With the increase in SiC content, only a slight decrease in energy band gap was observed (3.

A DFT Study of CO Hydrogenation on Faujasite-Supported Ir Clusters: on the Role of Water for Selectivity Control.

Reaction mechanisms for the catalytic hydrogenation of CO by faujasite-supported Ir clusters were studied by periodic DFT calculations. The reaction can proceed through two alternative paths. The thermodynamically favoured path results in the reduction of CO to CO, whereas the other, kinetically preferred channel involves CO hydrogenation to formic acid under water-free conditions.

TiO2-catalyzed synthesis of sugars from formaldehyde in extraterrestrial impacts on the early Earth.

Recent synthetic efforts aimed at reconstructing the beginning of life on our planet point at the plausibility of scenarios fueled by extraterrestrial energy sources. In the current work we show that beyond nucleobases the sugar components of the first informational polymers can be synthesized in this way. We demonstrate that a laser-induced high-energy chemistry combined with TiO2 catalysis readily produces a mixture of pentoses, among them ribose, arabinose and xylose.

The role of Ir4 cluster in enhancing the adsorption of CO2 on selected zeolites - GCMC simulations.

We have investigated the adsorption of CO2 molecules inside the EMT, SAO, SBS, SBT and IWS zeolites with respect to the influence of the Ir4 clusters on the adsorption capabilities of these materials. We have determined that the capabilities of CO2 adsorption depend on the combined effect of the framework topology and the position of the Ir4 cluster. Adsorption intensifies despite the fact that a fraction of the pore volume is occupied by the Ir4 cluster, and thus, the adsorption is more intense than that on empty zeolite.

Synergy between TiO2 and Co(x)O(y) sites in electrocatalytic water decomposition.

A computational study of the cooperative effect of a small four-atom Co oxide cluster supported on the TiO2 anatase (100) surface in the electrochemical water splitting reaction is presented. The results have been obtained including explicit solvent water molecules by means of Car-Parrinello MD simulations. Reaction steps in the catalytic cycle determined involve the formation of TiO2 surface hydroxyl groups as well as elementary reaction steps on the Co oxide cluster.

GCMC simulations of CO2 adsorption on zeolite-supported Ir4 clusters.

We have studied the adsorption of CO2 molecules inside the pores of faujasite zeolite and evaluated the influence of the Ir4 clusters on the intensity of the adsorption. The force field designed for CO2 adsorption in zeolites has been extended with the parameters for the CO2/Ir4 interactions, taking the Density Functional Theory (DFT) energies as a reference. We have found that despite the fraction of the pore volume that is occupied by the Ir4 cluster, the adsorption is more intense than that of empty faujasite.

DFT modeling of CO2 adsorption on Cu, Zn, Ni, Pd/DOH zeolite.

This study is the analysis of the adsorption process of the CO2 molecule on the cationic sites of the DOH zeolite. Based on the DFT method, we have been able to identify several adsorption sites containing extra-framework cations and evaluate the value of the adsorption energy with respect to the distance from the adsorption site. The zinc cation has been found to cause the strongest interaction with the CO2 molecule.

Conformation-dependent conductance through a molecular break junction.

Ab initio molecular dynamics simulations have been performed of a gold-1,4-benzenedithiol (BDT)-gold nanojunction under mechanical stress. For three different pulling rates between 10 and 40 m s(-1), it is found that the nanowire always ruptures between the second and third Au atom from the thiol sulfur. Larger rupture forces and longer extensions are required at higher pulling rates and vice versa.

Multiple zeolite structures from one ionic liquid template.

This study reports the use of 1-butyl-3-methyl imidazolium methanesulfonate ionic liquid as a template in the synthesis of zeolites. It is found that the silicon source determines the formation of beta (BEA), mordenite framework inverted (MFI), or analcime (ANA) zeolites. Depending on this source, different preorganized complexes are obtained that drive the formation of the different zeolite structures.