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101.
A Case of Strong Metal–Support Interactions: Combining Advanced Microscopy and Model Systems to Elucidate the Atomic Structure of Interfaces 下载免费PDF全文
Dr. Marc G. Willinger Dr. Wei Zhang Dr. Oleksandr Bondarchuk Dr. Shamil Shaikhutdinov Prof. Dr. Hans‐Joachim Freund Prof. Dr. Robert Schlögl 《Angewandte Chemie (International ed. in English)》2014,53(23):5998-6001
A symbiosis of advanced scanning probe and electron microscopy and a well‐defined model system may provide a detailed picture of interfaces on nanostructured catalytic systems. This was demonstrated for Pt nanoparticles supported on iron oxide thin films which undergo encapsulation by supporting oxide as a result of strong metal–support interactions. 相似文献
102.
Squeezing,Then Stacking: From Breathing Pores to Three‐Dimensional Ionic Self‐Assembly under Electrochemical Control 下载免费PDF全文
Kang Cui Dr. Kunal S. Mali Dr. Oleksandr Ivasenko Dongqing Wu Dr. Xinliang Feng Dr. Michael Walter Prof. Klaus Müllen Prof. Steven De Feyter Dr. Stijn F. L. Mertens 《Angewandte Chemie (International ed. in English)》2014,53(47):12951-12954
We demonstrate the spontaneous and reversible transition between the two‐ and three‐dimensional self‐assembly of a supramolecular system at the solid–liquid interface under electrochemical conditions, using in situ scanning tunneling microscopy. By tuning the interfacial potential, we can selectively organize our target molecules in an open porous pattern, fill these pores to form an auto‐host–guest structure, or stack the building blocks in a stratified bilayer. Using a simple electrostatic model, we rationalize which charge density is required to enable bilayer formation, and conversely, which molecular size/charge ratio is necessary in the design of new building blocks. Our results may lead to a new class of electrochemically controlled dynamic host–guest systems, artificial receptors, and smart materials. 相似文献
103.
Eugeniy N. Ostapchuk Andrey S. Plaskon Oleksandr O. Grygorenko Andrey A. Tolmachev Sergey V. Ryabukhin 《Journal of heterocyclic chemistry》2013,50(6):1299-1303
Chlorotrimethylsilane‐promoted Biginelli‐type reaction of benzaldehyde, acetoacetic acid derivatives, and various carboxyl‐containing ureas was explored. It was found that the steric load of the urea substituents influenced strongly the reaction outcome; in particular, the method was efficient only in the case of unbranched mono‐substituted ureas bearing either aliphatic or aromatic groups. The method allows performing a one‐pot, protecting group free synthesis of dihydropyrimidines possessing carboxylic functionality. 相似文献
104.
Cyrille Mbemba Katia Sigaud Florent Perret Kinga Suwinska Oleksandr Shkurenko Anthony W. Coleman 《Journal of inclusion phenomena and macrocyclic chemistry》2008,61(1-2):29-40
A series of mono-O-alkylated calix [4] arenes derivatives, with alkyl chain lengths of between 1 and 12 carbon atoms are reported. Monoalkylation is best achieved using potassium carbonate as the weak base and the respective alkyl iodide for chain lengths of one to three carbon atoms and using caesium fluoride as the base and the respective alkyl iodide for longer chain lengths. The mono-alkylated derivatives were converted into the tri-para-dimethylaminomethylene derivatives by the para-quinonemethide reaction in good yields. Surface tension measurements showed that at pH 2, 4, 6 and 8 all the tri-dimethylaminomethylene derivatives showed surfactant behaviour, and at pH 2 all show a Critical Micellar Concentration values. No correlation between Critical Micellar Concentration values and chain length is observed. Dynamic Light Scattering measurements showed that the CMC behaviour may be correlated with the observed aggregate sizes. The solid state structure of mono-O-ethoxy-calix[4]arene is described, in this structure a 1-D inclusion polymer is observed. 相似文献
105.
Solozhenko VL Kurakevych OO Turkevich VZ Turkevich DV 《The journal of physical chemistry. B》2008,112(21):6683-6687
X-ray diffraction with synchrotron radiation has been used to study in situ the chemical interaction of beta-rhombohedral boron with boron (III) oxide and phase relations in the B-B2O3 system at pressures up to 6 GPa in the temperature range from 300 to 2800 K. The B-B2O3 system has been thermodynamically analyzed, and its equilibrium phase diagram at 5 GPa has been constructed. Only one thermodynamically stable boron suboxide, B6O, exists in the system. It forms eutectic equilibria with boron and B2O3. 相似文献
106.
Qingyun Kang Mingyu Chu Prof. Panpan Xu Dr. Xuchun Wang Shiqi Wang Prof. Muhan Cao Prof. Oleksandr Ivasenko Prof. Tsun-Kong Sham Prof. Qiao Zhang Prof. Qiming Sun Prof. Jinxing Chen 《Angewandte Chemie (International ed. in English)》2023,62(47):e202313174
Chemical upcycling that catalyzes waste plastics back to high-purity chemicals holds great promise in end-of-life plastics valorization. One of the main challenges in this process is the thermodynamic limitations imposed by the high intrinsic entropy of polymer chains, which makes their adsorption on catalysts unfavorable and the transition state unstable. Here, we overcome this challenge by inducing the catalytic reaction inside mesoporous channels, which possess a strong confined ability to polymer chains, allowing for stabilization of the transition state. This approach involves the synthesis of p-Ru/SBA catalysts, in which Ru nanoparticles are uniformly distributed within the channels of an SBA-15 support, using a precise impregnation method. The unique design of the p-Ru/SBA catalyst has demonstrated significant improvements in catalytic performance for the conversion of polyethylene into high-value liquid fuels, particularly diesel. The catalyst achieved a high solid conversion rate of 1106 g ⋅ gRu−1 ⋅ h−1 at 230 °C. Comparatively, this catalytic activity is 4.9 times higher than that of a control catalyst, Ru/SiO2, and 14.0 times higher than that of a commercial catalyst, Ru/C, at 240 °C. This remarkable catalytic activity opens up immense opportunities for the chemical upcycling of waste plastics. 相似文献
107.
Oleksandr Ovsianytskyi Dr.-Ing. Maged F. Bekheet Dr.-Ing. Albert Gili Prof. Dr. Aleksander Gurlo 《Chemphyschem》2023,24(10):e202200775
The sensing response of metal oxides activated with noble metal nanoparticles is significantly influenced by changes to the chemical state of corresponding elements under operating conditions. Here, a PdO/rh-In2O3 consisting of PdO nanoparticles loaded onto rhombohedral In2O3 was studied as a gas sensor for H2 gas (100–40000 ppm in an oxygen-free atmosphere) in the temperature range of 25–450 °C. The phase composition and chemical state of elements were examined by resistance measurements combined with synchrotron-based in situ X-ray diffraction and ex situ X-ray photoelectron spectroscopy. As found, PdO/rh-In2O3 undergoes a series of structural and chemical transformations during operation: from PdO to Pd/PdHx and finally to the intermetallic InxPdy phase. The maximal sensing response (RN2/RH2) of ∼5 ⋅ 107 towards 40000 ppm (4 vol %) H2 at 70 °C is correlated with the formation of PdH0.706/Pd. The InxPdy intermetallic compounds formed around 250 °C significantly decrease the sensing response. 相似文献
108.
Dr. Oleksandr Ivanenko Tamara Pavlenko Dr. Yuliia Pohorenko Dr. Valeriy Bykov 《欧洲无机化学杂志》2023,26(28):e202300295
The article presents the results of research on the hydrothermal synthesis of nanoscale oxide of cobalt and zirconium and their mixed oxide compositions. The synthesized samples have been characterized by the X-ray phase, scanning electron microscopy and nitrogen adsorption-desorption methods; the composition of the samples has been determined by chemical analysis methods, and their catalytic activity in the decomposition of hydrogen peroxide has been studied. It has been shown that during synthesis, highly dispersed cobalt and zirconium oxide are formed, and the sample of the composition (mol %): Co3O4(88)−ZrO2(12) has the highest specific surface area (181.2 m2/g) and the highest activity (K=6.18 ⋅ 10−2 s−1) against the decomposition of hydrogen peroxide. The increasing of the ZrO2 content in oxide compositions reduces their catalytic activity. The particle size in the synthesized samples is 7–38 nm. 相似文献
109.
Yevheniia Husak Joanna Michalska Oleksandr Oleshko Viktoriia Korniienko Karlis Grundsteins Bohdan Dryhval Sahin Altundal Oleg Mishchenko Roman Viter Maksym Pogorielov Wojciech Simka 《Molecules (Basel, Switzerland)》2021,26(7)
The biodegradable metals, including magnesium (Mg), are a convenient alternative to permanent metals but fast uncontrolled corrosion limited wide clinical application. Formation of a barrier coating on Mg alloys could be a successful strategy for the production of a stable external layer that prevents fast corrosion. Our research was aimed to develop an Mg stable oxide coating using plasma electrolytic oxidation (PEO) in silicate-based solutions. 99.9% pure Mg alloy was anodized in electrolytes contained mixtures of sodium silicate and sodium fluoride, calcium hydroxide and sodium hydroxide. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), contact angle (CA), Photoluminescence analysis and immersion tests were performed to assess structural and long-term corrosion properties of the new coating. Biocompatibility and antibacterial potential of the new coating were evaluated using U2OS cell culture and the gram-positive Staphylococcus aureus (S. aureus, strain B 918). PEO provided the formation of a porous oxide layer with relatively high roughness. It was shown that Ca(OH)2 was a crucial compound for oxidation and surface modification of Mg implants, treated with the PEO method. The addition of Ca2+ ions resulted in more intense oxidation of the Mg surface and growth of the oxide layer with a higher active surface area. Cell culture experiments demonstrated appropriate cell adhesion to all investigated coatings with a significantly better proliferation rate for the samples treated in Ca(OH)2-containing electrolyte. In contrast, NaOH-based electrolyte provided more relevant antibacterial effects but did not support cell proliferation. In conclusion, it should be noted that PEO of Mg alloy in silicate baths containing Ca(OH)2 provided the formation of stable biocompatible oxide coatings that could be used in the development of commercial degradable implants. 相似文献
110.
Oleksandr Stroyuk Oleksandra Raievska Stefan Langner Christian Kupfer Anastasia Barabash Dmytro Solonenko Yuriy Azhniuk Jens Hauch Andres Osvet Miroslaw Batentschuk Dietrich R. T. Zahn Christoph J. Brabec 《Particle & Particle Systems Characterization》2021,38(10):2100169
The feasibility of a high-throughput robot-assisted synthesis of complex Cu1-xAgxInSySe1-x (CAISSe) quantum dots (QDs) by spontaneous alloying of aqueous glutathione-capped Ag–In–S, Cu–In–S, Ag–In–Se, and Cu–In–Se QDs is demonstrated. Both colloidal and thin-film core CAISSe and core/shell CAISSe/ZnS QDs are produced and studied by high-throughput semiautomated photoluminescence (PL) spectroscopy. The silver-copper-mixed QDs reveal clear evidence of a band bowing effect in the PL spectra and higher average PL lifetimes compared to the counterparts containing silver or copper only. The photophysical analysis of CAISSe and CAISSe/ZnS QDs indicates a composition-dependent character of the nonradiative recombination in QDs. The rate of this process is found to be lower for mixed copper-silver-based QDs compared to Cu- or Ag-only QDs. The combination of the band bowing effect and the suppressed nonradiative recombination of CAISSe QDs is beneficial for their applications in photovoltaics and photochemistry. The synergy of high-throughput robotic synthesis and a high-throughput characterization in this study is expected to grow into a self-learning synthetic platform for the production of metal chalcogenide QDs for light-harvesting, light-sensing, and light-emitting applications. 相似文献