The power of non-hydrolytic sol-gel chemistry: A review

This review is devoted to non-hydrolytic sol-gel chemistry. During the last 25 years, non-hydrolytic sol-gel (NHSG) techniques were found to be attractive and versatile methods for the preparation of oxide materials. Compared to conventional hydrolytic approaches, the NHSG route allows reaction control at the atomic scale resulting in homogeneous and well defined products. Due to these features and the ability to design specific materials, the products of NHSG reactions have been used in many fields of application. The aim of this review is to present an overview of NHSG research in recent years with an emphasis on the syntheses of mixed oxides, silicates and phosphates. The first part of the review highlights well known condensation reactions with some deeper insights into their mechanism and also presents novel condensation reactions established in NHSG chemistry in recent years. In the second section we discuss porosity control and novel compositions of selected materials. In the last part, the applications of NHSG derived materials as heterogeneous catalysts and supports, luminescent materials and electrode materials in Li-ion batteries are described. © 2017 by the authors. Licensee MDPI, Basel, Switzerland.LO1504, MŠMT, Ministerstvo Školství, Mládeže a Tělovýchovy; LQ1601, MŠMT, Ministerstvo Školství, Mládeže a TělovýchovyMinistry of Education, Youth and Sports of the Czech Republic under the project CEITEC [LQ1601]; Ministry of Education, Youth and Sports of the Czech Republic under Program NPU I [LO1504]; Center for Direct Catalytic Conversion of Biomass to Biofuels (C3Bio); Energy Frontier Research Center - U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences [DESC0000997]; DOE BES [DE-FG02-01ER15259

Ag-Cu Colloid Synthesis: Bimetallic Nanoparticle Characterisation and Thermal Treatment

The Ag-Cu bimetallic colloidal nanoparticles (NPs) were prepared by solvothermal synthesis from metalloorganic precursors in a mixture of organic solvents. The nanoparticles were characterized by dynamic light scattering (DLS) and small angle X-ray scattering (SAXS). The properties of metallic core and organic shell of the nanoparticles were studied by direct inlet probe mass spectrometry (DIP/MS), Knudsen effusion mass spectrometry (KEMS), double-pulse laser-induced breakdown spectroscopy (DPLIBS), and differential scanning calorimetry (DSC). The transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used for particle characterization before and after thermal analysis. The experiment yielded results that were for AgCu nanoparticles for the first time. The detected liquidus temperature has been compared with the prediction obtained from calculation of the phase diagram of Ag-Cu nanoalloy. The experimental results show that of near-eutectic composition AgCu nanoparticles possess the fcc crystal lattice. Surprisingly, spinodal decomposition was not observed inside the AgCu nanoparticles at temperatures up to 230C. The depression of the eutectic AgCu melting point was calculated but not observed. The eutectic AgCu microparticles are formed before melting.Ag-Cu bimetalické koloidní nanočástice (NPs) byly připraveny solvotermální syntézou z metalických prekurzorů ve směsi organických rozpouštědel. Nanočástice byly charakterizovány metodami: DLS a SAXS. Vlastnosti kovového jádra a stabilizační obálky z organických látek byly studovány metodou přímého vstupu do hmotnostního spektrometru (DIP/MS), Knutsenovou hmotnostní spektrometrií (KEMS), double -pulse laserovou spektroskopií (DPLIBS) a diferenční skenovací kalorimetrií (DSC). Transmisní elektronová mikroskopie (TEM) a řádkovací elektronová mikroskopie (SEM) byly použity pro charakterizaci částic před a po termické analýze. Teplota likvidu zjištěna experimentálně byla srovnávána s predikcí fázového diagramu Ag-Cu nanoslitiny. Experimentální výsledky ukázaly téměř eutektické složení a fcc krystalovou mřížku AgCu NPs. Překvapivě, spinodální rozklad nanočástic nebyl pozorován při teplotách do 230C

Ring formation and hydration effects in electron attachment to misonidazole

This research was funded by CZECH SCIENCE FOUNDATION grant number 19-01159S; Czech Ministry of Education Youth and Sports via OP RDE Grant no. CZ.02.2.69/0.0/16_027/0008355; S.D. acknowledges funding from the FWF, Vienna (P30332).We study the reactivity of misonidazole with low-energy electrons in a water environment combining experiment and theoretical modelling. The environment is modelled by sequential hydration of misonidazole clusters in vacuum. The well-defined experimental conditions enable computational modeling of the observed reactions. While the NO- 2 dissociative electron attachment channel is suppressed, as also observed previously for other molecules, the OH- channel remains open. Such behavior is enabled by the high hydration energy of OH- and ring formation in the neutral radical co-fragment. These observations help to understand the mechanism of bio-reductive drug action. Electron-induced formation of covalent bonds is then important not only for biological processes but may find applications also in technology.publishersversionpublishe

Copper phosphinate complexes as molecular precursors for ethanol dehydrogenation catalysts

Nowadays, the production of acetaldehyde heavily relies on the petroleum industry. Developing new catalysts for the ethanol dehydrogenation process that could sustainably substitute current acetaldehyde production methods is highly desired. Among the ethanol dehydrogenation catalysts, copper-based materials have been intensively studied. Unfortunately, the Cu-based catalysts suffer from sintering and coking, which lead to rapid deactivation with time-on-stream. Phosphorus doping has been demonstrated to diminish coking in methanol dehydrogenation, fluid catalytic cracking, and ethanol-to-olefin reactions. This work reports a pioneering application of the well-characterized copper phosphinate complexes as molecular precursors for copper-based ethanol dehydrogenation catalysts enriched with phosphate groups (Cu-phosphate/SiO2). Three new catalysts (CuP-1, CuP-2, and CuP-3), prepared by the deposition of complexes {Cu(SAAP)}n (1), [Cu6(BSAAP)6] (2), and [Cu3(NAAP)3] (3) on the surface of commercial SiO2, calcination at 500 °C, and reduction in the stream of the forming gas 5% H2/N2 at 400 °C, exhibited unusual properties. First, the catalysts showed a rapid increase in catalytic activity. After reaching the maximum conversion, the catalyst started to deactivate. The unusual behavior could be explained by the presence of the phosphate phase, which made Cu2+ reduction more difficult. The phosphorus content gradually decreased during time-on-stream, copper was reduced, and the activity increased. The deactivation of the catalyst could be related to the copper diffusion processes. The most active CuP-1 catalyst reaches a maximum of 73% ethanol conversion and over 98% acetaldehyde selectivity at 325 °C and WHSV = 2.37 h-1CF BIC; European Regional Development Fund-Project “UP CIISB, (CZ.02.1.01/0.0/0.0/18_046/0015974, LM2018110); Grant Agency of Masaryk University, (CZ.02.01.01/00/22_008/0004572, MUNI/A/1298/2022, MUNI/J/0007/2021, QM4ST); Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT, (LM2018127, LM2023042, LM2023056, RP/CPS/2022/007); Grantová Agentura České Republiky, GA ČR, (GJ20-03636Y); Central European Institute of Technology, CEITECMEYS CR [LM2023042, LM2018127, CZ.02.1.01/0.0/0.0/18_046/0015974]; European Regional Development Fund-Project "UP CIISB" [LM2018110]; Czech Science Foundation [GJ20-03636Y]; Grant Agency of Masaryk University [MUNI/J/0007/2021, MUNI/A/1298/2022]; Quantum Materials for Applications in Sustainable Technologies (QM4ST) [CZ.02.01.01/00/22_008/0004572]; Ministry of Education, Youth and Sports of the Czech Republic [LM2023056]; Ministry of Education, Youth and Sports of the Czech Republic [RP/CPS/2022/007

Alban Berg and his Lyric suite

This thesis deals with an analysis of Lyric suite by Alban Berg concerning the little known facts based on the fascinating discovery of the annotated copy of the score from the year 1977. This score was prepared by the composer himself for Hanna Fuchs-Robettin. The analalysis explores the individual movements according to motives, numeric symbolism, symbolic tone rows and last but not least the thematic connections between the movements

Implementation strategies of dense index files

V diplomové práci je popsána problematika správy dat na externích paměťových médiích se zaměřením na datovou strukturu Soubor s úplným indexem a popsána vlastní implementace této datové struktury. Součástí implementace je i animace datové struktury Soubor s úplným indexem.Druh animace, který byl navrhnut, je vhodný pro animaci všech druhů k-cestných stromů.Katedra informatiky v dopravěDokončená práce s úspěšnou obhajobo

B-tree application in indexed files

Práce se zabývá návrhem a implementací abstraktní datové struktury a její aplikace v organizacích indexovaných souborů.Dokončená práce s úspěšnou obhajobo

LC-NMR Analysis of Phenylsilane Polymers

We report the analysis of dehydrocoupling polymerization reactions of phenylsilane via on-flow LC-NMR experiment. The successful separation was achieved by isocratic elution of acetonitrile and aceton (80:20). The separation was solely monitored by 1H NMR detection. The properties of the polymeric product depend on the catalytical system. The products can differ in the molar weight distribution, degree of branching and amount of cyclic and rearranged products. In our particular cases, the weight average molar mass (Mw) varies from several silane units up to 4100 g.mol-1. The branching of polysilanes is monitored by 29Si{1H} INEPT experiment with the polarization transfer from the ortho hydrogen (J~7 Hz). The connectivity within branched unit was established via 1H à 29Si-29Si INEPT-INADEQUATE experiment

29Si NMR Phenylsilane Polymer Analysis

Here we focus on the analysis od dehydrocoupling polymerization reactions of phenylsilane. the molar mass distribution depends on the catalytic system and can be easily monitored by on-flow LC-NMR experiment