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Author |
Ennaert, T.; Geboers, J.; Gobechiya, E.; Courtin, C.M.; Kurttepeli, M.; Houthoofd, K.; Kirschhock, C.E.A.; Magusin, P.C.M.M.; Bals, S.; Jacobs, P.A.; Sels, B.F. |
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Title |
Conceptual frame rationalizing the self-stabilization of H-USY zeolites in hot liquid water |
Type |
A1 Journal article |
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Year  |
2015 |
Publication |
ACS catalysis |
Abbreviated Journal |
Acs Catal |
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Volume |
5 |
Issue |
5 |
Pages |
754-768 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The wide range of liquid-phase reactions required for the catalytic conversion of biomass compounds into new bioplatform molecules defines a new set of challenges for the development of active, selective, and stable catalysts. The potential of bifunctional Ru/H-USY catalysts for conversions in hot liquid water (HLW) is assessed in terms of physicochemical stability and long-term catalytic performance of acid sites and noble metal functionality, as probed by hydrolytic hydrogenation of cellulose. It is shown that zeolite desilication is the main zeolite degradation mechanism in HLW. USY zeolite stability depends on two main parameters, viz., framework and extra-framework aluminum content. The former protects the zeolite lattice by counteracting hydrolysis of framework bonds, and the latter, when located at the external crystal surface, prevents solubilization of the zeolite framework which is the result of its low water-solubility. Hence, the hot liquid water stability of commercial H-USY zeolites, in contrast to their steam stability, increased with decreasing Si/AI ratio. As a result, mildly steamed USY zeolites containing a high amount of both Al species exhibit the highest resistance to HLW. During an initial period of transformations, Al-rich zeolites form additional protective extra-framework Al species at the outer surface, self-stabilizing the framework. A critical bulk Si/AI ratio of 3 was determined whereby USY zeolites with a lower Si/AI ratio will self-stabilize over time. Besides, due to the initial transformation period, the accessibility of the catalytic active sites is extensively enhanced resulting in a material that is more stable and drastically more accessible to large substrates than the original zeolite. When these findings are applied in the hydrolytic hydrogenation of cellulose, unprecedented nearly quantitative hexitol yields were obtained with a stable catalytic system. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Wos |
000349275300031 |
Publication Date |
2014-12-09 |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2155-5435;2155-5435; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
10.614 |
Times cited |
65 |
Open Access |
OpenAccess |
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Notes |
335078 Colouratom; ECAS_Sara; (ROMEO:white; preprint:; postprint:restricted 12 months embargo; pdfversion:cannot); |
Approved |
Most recent IF: 10.614; 2015 IF: 9.312 |
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Call Number |
c:irua:125288 |
Serial |
474 |
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Author |
Corthals, S.; van Noyen, J.; Geboers, J.; Vosch, T.; Liang, D.; Ke, X.; Hofkens, J.; Van Tendeloo, G.; Jacobs, P.; Sels, B. |
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Title |
The beneficial effect of CO2 in the low temperature synthesis of high quality carbon nanofibers and thin multiwalled carbon nanotubes from CH_{4} over Ni catalysts |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Carbon |
Abbreviated Journal |
Carbon |
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Volume |
50 |
Issue |
2 |
Pages |
372-384 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
A low temperature chemical vapor deposition method is described for converting CH4 into high-quality carbon nanofibers (CNFs) using a Ni catalyst supported on either spinel or perovskite oxides in the presence of CO2. The addition of CO2 has a significant influence on CNF purity and stability, while the CNF diameter distribution is significantly narrowed. Ultimately, the addition of CO2 changes the CNF structure from fishbone fibers to thin multiwalled carbon nanotubes. A new in situ cooling principle taking into account dry reforming chemistry and thermodynamics is introduced to account for the structural effects of CO2. |
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Thesis |
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Publisher |
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Place of Publication |
Oxford |
Editor |
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Wos |
000297397700004 |
Publication Date |
2011-09-01 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0008-6223; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.337 |
Times cited |
26 |
Open Access |
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Notes |
Iwt; Iap |
Approved |
Most recent IF: 6.337; 2012 IF: 5.868 |
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Call Number |
UA @ lucian @ c:irua:93626 |
Serial |
228 |
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Author |
Philippaerts, A.; Goossens, S.; Vermandel, W.; Tromp, M.; Turner, S.; Geboers, J.; Van Tendeloo, G.; Jacobs, P.A.; Sels, B.F. |
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Title |
Design of Ru-zeolites for hydrogen-free production of conjugated linoleic acid |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Chemsuschem |
Abbreviated Journal |
Chemsuschem |
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Volume |
4 |
Issue |
6 |
Pages |
757-767 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
While conjugated vegetable oils are currently used as additives in the drying agents of oils and paints, they are also attractive molecules for making bio-plastics. Moreover, conjugated oils will soon be accepted as nutritional additives for functional food products. While current manufacture of conjugated vegetable oils or conjugated linoleic acids (CLAs) uses a homogeneous base as isomerisation catalyst, a heterogeneous alternative is not available today. This contribution presents the direct production of CLAs over Ru supported on different zeolites, varying in topology (ZSM-5, BETA, Y), Si/Al ratio and countercation (H+, Na+, Cs+). Ru/Cs-USY, with a Si/Al ratio of 40, was identified as the most active and selective catalyst for isomerisation of methyl linoleate (cis-9,cis-12 (C18:2)) to CLA at 165 °C. Interestingly, no hydrogen pre-treatment of the catalyst or addition of hydrogen donors is required to achieve industrially relevant isomerisation productivities, namely, 0.7 g of CLA per litre of solvent per minute. Moreover, the biologically most active CLA isomers, namely, cis-9,trans-11, trans-10,cis-12 and trans-9,trans-11, were the main products, especially at low catalyst concentrations. Ex situ physicochemical characterisation with CO chemisorption, extended X-ray absorption fine structure measurements, transmission electron microscopy analysis, and temperature-programmed oxidation reveals the presence of highly dispersed RuO2 species in Ru/Cs-USY(40). |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Weinheim |
Editor |
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Wos |
000292214000009 |
Publication Date |
2011-04-20 |
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Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1864-5631; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
7.226 |
Times cited |
24 |
Open Access |
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Notes |
Fwo |
Approved |
Most recent IF: 7.226; 2011 IF: 6.827 |
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Call Number |
UA @ lucian @ c:irua:90352 |
Serial |
660 |
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Author |
Van de Vyver, S.; Geboers, J.; Dusselier, M.; Schepers, H.; Vosch, T.; Zhang, L.; Van Tendeloo, G.; Jacobs, P.A.; Sels, B.F. |
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Title |
Selective bifunctional catalytic conversion of cellulose over reshaped ni particles at the tip of carbon nanofibers |
Type |
A1 Journal article |
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Year |
2010 |
Publication |
Chemsuschem |
Abbreviated Journal |
Chemsuschem |
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Volume |
3 |
Issue |
6 |
Pages |
698-701 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Weinheim |
Editor |
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Language |
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Wos |
000279753300011 |
Publication Date |
2010-05-05 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1864-5631;1864-564X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
7.226 |
Times cited |
136 |
Open Access |
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Notes |
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Approved |
Most recent IF: 7.226; 2010 IF: 6.325 |
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Call Number |
UA @ lucian @ c:irua:95657 |
Serial |
2962 |
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