Wyniki wyszukiwania - BazTech

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Katalizatory złotowe osadzone na zeolitach

Walkowiak Adrian

Wiadomości Chemiczne

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2021

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[Z] 75, 11-12

1259--1293

EN

Heterogeneous gold catalysis is a relatively young but dynamically developing field of chemistry. At the end of the 1980s, Masatake Haruta and Graham Hutchings provided experimental evidence of high activity of supported gold catalysts in CO oxidation and acetylene hydrochlorination. Thus, these two researchers challenged the prevailing chemists’ belief that gold is almost completely chemically inert and catalytically inactive. Since then, gold catalysis has been constantly in the centre of attention of a wide array of scientists from around the world. However, there are still many questions about the nature of catalysts containing this noble metal, which inspires in-depth research in this field. From among various potential supports for gold heterogeneous catalysts, zeolites have drawn much attention thanks to several unique properties of this group of materials, among which the most important are high thermal stability and the presence of a system of pores of strictly defined sizes. Zeolites have extremely large surface area, which is desirable to obtain high dispersion of the active phase. The article provides a concise overview of the methods of gold nanoparticles deposition on zeolitic supports and catalytic applications of such materials. The first chapter sheds light on the properties of bulk and nano-sized Au and depicts the background of gold catalysis development. In the following part, a brief description of zeolites and their properties is delivered. The third chapter is devoted entirely to the description of several preparation methods of zeolite-supported gold catalysts and their applications in different catalytic processes. The following post-synthetic methods of zeolite modification with gold are described: impregnation, ion exchange, deposition-reduction, chemical vapour deposition, and grafting. The most important advantages and disadvantages of each method are summarized. The article concludes with a résumé of literature reports concerning the use of zeolitesupported gold catalysts in various processes. Special attention was paid to selective oxidation of alcohols and biomass-derived chemicals (e.g. glucose).

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Wpływ powłok z własnościami katalitycznymi na ograniczenie emisji tlenku węgla

Morel S.

Hutnik, Wiadomości Hutnicze

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2015

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Vol. 82, nr 5

375--378

PL

W artykule przedstawiono katalityczne dopalanie tlenku węgla jako jedną z metod umożliwiającą ograniczenie emisji zanieczyszczeń z procesów spalania paliw. Przedstawiono wyniki badań dotyczących katalitycznego oddziaływania ceramicznych powłok natryskanych plazmowo na powierzchnie ograniczające przestrzenie spalania na kształtowanie się profilu rozkładu temperatury i zawartość tlenku węgla w spalinach. Procesy katalitycznego dopalania realizowano w modelowej komorze, która w środkowej części wypełniona była ceramicznymi kształtkami z natryskanymi katalitycznymi powłokami. Uzyskane wyniki pomiarów uzasadniają celowość stosowania powłok katalizujących procesy dopalania tlenku węgla w piecach i urządzeniach cieplnych w których spala się paliwa zwierające węgiel.

EN

Paper presents research on the temperature distribution and CO and CO2 content during combustion process in a tube furnace. The walls of combustion chamber were sprayed with cerium, manganese and copper oxide catalytic coatings. The furnace was gas-fired and combustion was realized for different values of excess air ratio. It was observed that combustion gas temperature dependly on the type of the sprayed coating increases in range of several to even a dozen per cent with decrease of CO content in combustion gases. These parameters strongly depend on excess air flow which value should not be lower than 0.9. Other part of the paper shows the investigations and measurements of temperature distribution and CO and CO2 concentration in combustion gas during flow through recuperatur caoted with oxide layer. in which city gas was burned at excess air number within the range of 0.8÷1.1. Application of the plasma sprayed coatings on recuperator pipes sur- face, result in signficant decrease of CO concentration in combustion gases and about 10% incerease of combustion gas temperature, mainly in the central part of recuperator. Research allow for the choice of the best plasma sprayed coatings materials and their mixture of Ce02 and A1203. Results also confirm the purposefulness of plasma sprayed catalytic coatings application for afterburning processes.

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Synteza karbofunkcyjnych propylotri(alkoksy, metylo) silanów

Guliński J., Marciniec B., Maciejewski H., Pancer K., Dąbek I., Fiedorow R.

Przemysł Chemiczny

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2003

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T. 82, nr 8-9

605-607

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Odwodornienie propanu do propenu w obecności CO2 na wybranych katalizatorach tlenkowych

Michorczyk P., Ogonowski J.

Czasopismo Techniczne. Chemia

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2002

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R. 99, z. 3-Ch

41--44

EN

Dehydrogenation of propane to propene in the presence of carbon dioxide was carried out over unsupported (MoO3, CeO2, Al2O3, ZrO2, SiO2 and Yb2O3) and supported (MoO3/SiO2 and MoO3/Al2O3) oxide catalysts. The highest yield of propene (about 6,2%) with selectivity of above 63% was obtained using MoO3 catalyst. It was also found that the conversion and products distributions very depending on the catalyst and supports.