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1

Preparation and Characterization of the Colloidal Ru/g-Al2O3 Catalysts

Okal J.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 2

293-302

EN

Highly dispersed ruthenium nanoparticles were prepared by a microwave-assisted polyol heating process and supported on g-alumina. The structure of the Ru/g-Al2O3 catalysts with different metal loadings was investigated using BET, XRD, TEM and HRTEM. The chemisorption of hydrogen and oxygen on the resultant supported metal materials was investigated as a means of determining the dispersion of the samples. Electron microscopy showed that the Ru nanoparticles were uniformly distributed on the alumina surface and their mean size slightly increased from 1.3 to 2.1 nm with Ru loading rising from 1.2 to 8.6 wt.%. For all samples, oxygen adsorbtion at RT was somewhat higher than at 0°C indicating some subsurface oxidation of small Ru nanoparticles. This process does not, however, affect significantly the Ru dispersion calculated from the O2 up takes at 0°C or at RT. Assuming a stoichiometry O/Rus = 2, good agreement was obtained between the average Ru particle size calculated from O2 and H2 adsorbtion and TEM data. The formation of the surface oxide with stoichiometry close to RuO2 on the surface of the Ru metal nanoparticles after O2 up take measurements was established, but no such phase was detected by HRTEM. Much lower value of O/Rus < 1 was found, however, for the catalyst with the high est Ru loading. A large discrepancy between the results of O2 adsorbtion and TEM for this sample was interpreted as an indication of partial encapsulation of the Ru particles with the support and/or that the metal surface was not reduced completely.

2

Hydrogen chemisorption on palladium surface in a high electric field

Tomaszewska A., Stępień Z. M.

Optica Applicata

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2005

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Vol. 35, nr 3

375-383

EN

Interaction of hydrogen with palladium surface in the presence of high electric field leads to the formation of complexes, which have been recorded as PdHx + (x = 1, 2, 3, 4). In the present work, quantum chemical calculations with Becke's three parameter hybrid functional using the LYP correlation functional (B3LYP) for hydrogen interaction with both single palladium atom and four- or six-atom clusters (such us tetra- and octahedral voids) have been performed. The binding energies, ionization potentials and free-space dipole moments for PdHx (x = 1, 2, 3, 4) molecules have been determined and the "critical" field values, characteristic of palladium hydrides field dissociation have been determined. The model of hydrogen adsorption in the threefold hollow site on the surface together with a subsurface interstitial chemisorption has been discussed. It has been found that hydrogen is bound more strongly in the tetrahedral void than in the octahedral one.

3

Efekty SMSI w katalizatorach Pt/WO3/Al2O3

Farbotko J., Rynkowski J., Touroude R.

Zeszyty Naukowe. Chemia / Politechnika Łódzka

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1998

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Z. 46

133-146

PL

W pracy porównano właściwości adsorpcyjno-desorpcyjne katalizatora 3.5%Pt/10%WO3/Al2O3 z klasycznymi układami 3.5%Pt/Al2O3 i 4.7%Pt/TiO2. Przedstawiono możliwość wykorzystania chemisorpcji i metod z programowanym wzrostem temperatury do określenia warunków indukowania i typu występującego stanu SMSI. Określono także różnice aktywności katalitycznej tych układów i ich selektywności w zależności od rodzaju i stopnia wywołanego stanu SMSI w reakcji uwodornienia aldehydu krotonowego.

EN

The adsorptive-desorptive properties of 3.5%Pt/WO3/Al2O3 catalyst with the classic systems Pt/Al2O3 and Pt/TiO2 were compared in this paper. We also presented possibilities of the application of chemisorption and the temperature-programmed methods to determine the SMSI effect. The activity and selectivity of these catalysts in the croton aldehyde hydrogenation depend on SMSI type.

4

Charakteryzacja układów binarnych CeO2-TiO2 oraz katalizatorów Pt/CeO2-TiO2

Rynkowski J., Lenik J., Sobota R.M., Szynkowska M.I., Affrossman S.

Zeszyty Naukowe. Chemia / Politechnika Łódzka

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1998

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Z. 46

81-102

PL

W pracy przedstawiono wyniki badań natury, właściwości powierzchniowych oraz podatności na redukcję binarnych układów tlenkowych CeO2-TiO2 oraz naniesionych na nie katalizatorów platynowych przy zastosowaniu różnorodnych metod badawczych (TPR, TPO, BET, XRD, XPS, chemisorpcja wodoru, testy aktywności katalitycznej).

EN

This work presents the results of studies on the nature, surface properties and susceptibility to the reduction of binary oxide systems CeO2-TiO2 and supported on them platinum catalysts using different research methods (TPR, TPO, BET, XRD, XPS, hydrogen chemisorption, catalytic activity tests).