30 research outputs found
THE INTERACTION OF HUMAN OSTEOBLAST-LIKE Saos-2 CELLS WITH STAINLESS STEEL AND Si(100) COATED BY SILICALITE 1 FILMS
Interaction of osteoblast-like Saos-2 cells with stainless steel and Si(100) covered by a film of densely intergrown silicalite-1 crystals is investigated. Surface properties of the films are tuned by synthesis conditions and post-synthetic modifications. A number of adhered cells is affected by surface morphology and wettability of the film
REMOVAL OF DIQUATERNARY AMMONIUM CATIONS FROM AS-SYNTHESIZED SSZ-16 ZEOLITE
Zeolites are stable microporous aluminosilicates with numerous applications in chemical technology such as separation of species and catalytic transformations. Our study is focused on a weakly explored zeolite SSZ-16 with pore constrictions defined by 8-membered oxygen rings. Key results are the preparation of Et6-diquat-5 dication used as a structure directing agent (SDA) and finding the optimum synthesis conditions with respect to zeolite phase purity. Stability of SDA was examined in conditions similar to those of autoclave synthesis (concentration, pH, temperature). Moreover, the content and location of SDA species in zeolite phase and conditions of SDA decomposition were investigated
THE INTERACTION OF HUMAN OSTEOBLAST-LIKE SAOS-2 CELLS WITH STAINLESS STEEL AND SI(100) COATED BY SILICALITE 1 FILMS
Interaction of osteoblast-like Saos-2 cells with stainless steel and Si(100) covered by a film of densely intergrown silicalite-1 crystals is investigated. Surface properties of the films are tuned by synthesis conditions and post-synthetic modifications. A number of adhered cells is affected by surface morphology and wettability of the film.</p
Catalytic Properties of 3D Graphene-Like Microporous Carbons Synthesized in a Zeolite Template
[EN] The inherent properties of a single atomic carbon layer in graphene offer opportunities for the creation of catalytically active centers tailored on a molecular level on a support with high thermal stability and very high specific surface area. We demonstrate that organization of the two-dimensional system of the carbon layer into three-dimensional (3D) graphene-like catalytic materials with the connectivity of a pore network providing good accessibility to the active centers allows the preparation of catalytic materials that exploit the properties of graphene. In this study, 3D graphene-like microporous carbons, denoted as)6 beta-carbon and Y-carbon, were synthesized by nanocasting of beta (*BEA) and faujasite (FAU) zeolite templates. Structural analyses show that the materials are characterized by 3D-assembled and highly stable single-atom graphene an open porous system resembling the regular channel system of the zeolites with a specific surface area comparable to the surface area of graphene. The materials effectively catalyze the hydrogenation of alkenes, alkynes, and cycloalkenes into the corresponding alkanes and cycloalkanes. The materials facilitate catalytic intramolecular rearrangements, including the selective isomerization of double bonds and branching of linear chains, as well as stereoselective isomerization of unsaturated hydrocarbons. layers that formThis work was supported by the Grant Agency of the Czech Republic under project No. 15-12113S. The authors acknowledge the assistance provided by the Research Infrastructures NanoEnviCz (Project No. LM2015073) and Pro-NanoEnviCz (Project No. CZ.02.1.01/0.0/0.0/16_013/0001821), supported by the Ministry of Education, Youth and Sports of the Czech Republic.Sazama, P.; Pastvova, J.; Rizescu, C.; Tirsoaga, A.; Parvulescu, VI.; García Gómez, H.; Kobera, L.... (2018). Catalytic Properties of 3D Graphene-Like Microporous Carbons Synthesized in a Zeolite Template. ACS Catalysis. 8(3):1779-1789. https://doi.org/10.1021/acscatal.7b04086S177917898
Application of Electron Spectroscopy for Chemical Analysis (ESCA) in Solid State Chemistry
Possibilities of extraction of the chemical information from the photoelectron and auger spectra of insulators is oveviewed. The examples based on original experiments proceeded in our laboratory are presented
Protective Sliding Carbon-Based Nanolayers Prepared by Argon or Nitrogen Ion-Beam Assisted Deposition on Ti6Al4V Alloy
The microstructure and the surface properties of samples coated by carbon-based nanolayer were investigated in an effort to increase the surface hardness and reduce the coefficient of friction of the Ti6Al4V alloy. Protective carbon-based nanolayers were fabricated by argon or nitrogen ion-beam assisted deposition at ion energy of 700 eV on Ti6Al4V substrates. The Raman spectra indicated that nanolayers had a diamond-like carbon character with sp2 rich bonds. The TiC and TiN compounds formed in the surface area were detected by X-ray diffraction. Nanoscratch tests showed increased adhesion of a carbon-based nanolayer deposited with ion assistance in comparison with a carbon nanolayer deposited without ion assistance. The results showed that argon ion assistance leads to greater nanohardness than a sample coated by a carbon-based nanolayer with nitrogen ion assistance. A more than twofold increase in nanohardness and a more than fivefold decrease in the coefficient of friction were obtained for samples coated by a carbon-based nanolayer with ion assistance, in comparison with the reference sample
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NO decomposition in non-reducing atmospheres. Technical progress report, December 1994--February 1995
The overall goal of this research is to establish the fundamental science needed to develop catalysts that will exhibit high activity and selectivity in the decomposition of NO into N{sub 2} and O{sub 2}. This project is centered on the preparation, characterization, and testing of transition metal exchanged catalysts, especially Co(III) zeolites. Additional Co(II) exchanged A zeolite samples have been prepared in aqueous solution at pH = 5.0-6.1 that contain different exchange levels of Co(II). Some of these have been analyzed for Na and Co contents by chemical methods and by X-ray photoelectron spectroscopy. It was shown that preparation of the samples by ion exchange between pH {approx}6 and 7 tended to give stoichiometric ion exchange of Co(II) for Na{sup +}. However, ion exchange at lower pH tended to lead to exchange with H{sup +} while ion exchange at higher pH tended to lead to the presence of excess Co(H), probably by precipitation of a basic Co phase. Systematic analyses of Na A zeolite, CO(II) A zeolites, and Co(II)/Ce(III) A zeolites, as well as Na X zeolite, Na Y zeolite, and Na mordenite for comparison purposes, have been carried out by X-ray photoelectron spectroscopy and Auger spectroscopy methods. Complete data analysis has not yet been carried out, but trends in some parameters have been noted, e.g. the relative intensity of the O KL{sub 2,3}L{sub 2,3} line in the O ls spectral region increases as the Si Al ratio of the Na zeolites increases