Records |
Author |
Geukens, I.; Vermoortele, F.; Meledina, M.; Turner, S.; Van Tendeloo, G.; De Vos, D.E. |
Title |
Ag nanoparticles on mixed Al2O3-Ga2O3 supports as catalysts for the N-alkylation of amines with alcohols |
Type |
A1 Journal article |
Year |
2014 |
Publication |
Applied catalysis : A : general |
Abbreviated Journal |
Appl Catal A-Gen |
Volume |
469 |
Issue |
|
Pages |
373-379 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
The combination of AgNO3 with NaH results in Ag nanoparticles that can selectively perform alcohol aminations under mild reaction conditions (110 °C). NaH not only serves as a reducing agent for the Ag salt, but also activates the alcohol for dehydrogenation to the corresponding ketone/aldehyde. The stability of the particles can be improved by immobilizing them onto mixed Al2O3Ga2O3 supports; the combination of Ga and Al provides materials with stronger Lewis acidic sites compared to pure alumina or gallium oxide supports. This leads to catalysts with enhanced activities, without the necessity of adding external Lewis acids. Detailed TEM characterization also reveals a close interaction between the Ag NPs and the gallium oxide phase. The obtained catalysts are recyclable and show activity for the alcohol amination using a variety of aliphatic and aromatic amines under mild conditions. |
Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000329266500045 |
Publication Date |
2013-10-10 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0926-860X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.339 |
Times cited |
24 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 4.339; 2014 IF: 3.942 |
Call Number |
UA @ lucian @ c:irua:111095 |
Serial |
83 |
Permanent link to this record |
|
|
|
Author |
Zhao, Q.; Lorenz, H.; Turner, S.; Lebedev, O.I.; Van Tendeloo, G.; Rameshan, C.; Klötzer, B.; Konzett, J.; Penner, S. |
Title |
Catalytic characterization of pure SnO2 and GeO2 in methanol steam reforming |
Type |
A1 Journal article |
Year |
2010 |
Publication |
Applied catalysis : A : general |
Abbreviated Journal |
Appl Catal A-Gen |
Volume |
375 |
Issue |
2 |
Pages |
188-195 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Structural changes of a variety of different SnO, SnO2 and GeO2 catalysts upon reduction in hydrogen were correlated with associated catalytic changes in methanol steam reforming. Studied systems include SnO, SnO2 and GeO2 thin film model catalysts prepared by vapour phase deposition and growth on polycrystalline NaCl surfaces and, for comparison, the corresponding pure oxide powder catalysts. Reduction of both the SnO2 thin film and powder at around 673 K in 1 bar hydrogen leads to a substantial reduction of the bulk structure and yields a mixture of SnO2 and metallic β-Sn. On the powder catalyst this transformation is fully reversible upon oxidation in 1 bar O2 at 673 K. Strongly reduced thin films, however, can only be re-transformed to SnO2 if the reduction temperature did not exceed 573 K. For GeO2, the situation is more complex due to its polymorphism. Whereas the tetragonal phase is structurally stable during reduction, oxidation or catalytic reaction, a small part of the hexagonal phase is always transformed into the tetragonal at 673 K independent of the gas phase used. SnO2 is highly active and CO2 selective in methanol steam reforming, but the initial high activity drops considerably upon reduction between 373 and 573 K and almost complete catalyst deactivation is observed after reduction at 673 K, which is associated with the parallel formation of β-Sn. In close correlation to the structural results, the catalytic activity and selectivity can be restored upon an oxidative catalyst regeneration at 673 K. Tetragonal GeO2 exhibits only a small activity and no pronounced selectivity to either CO or CO2, at least after reduction. In its fully oxidized state release of surface/lattice oxygen results in a non-catalytic formation of CO2 by oxidation of CO originating from catalytic dehydrogenation. |
Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000275580600002 |
Publication Date |
2010-01-15 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0926-860X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.339 |
Times cited |
20 |
Open Access |
|
Notes |
Esteem 026019 |
Approved |
Most recent IF: 4.339; 2010 IF: 3.384 |
Call Number |
UA @ lucian @ c:irua:81741 |
Serial |
292 |
Permanent link to this record |
|
|
|
Author |
Lorenz, H.; Zhao, Q.; Turner, S.; Lebedev, O.I.; Van Tendeloo, G.; Kloetzer, B.; Rameshan, C.; Pfaller, K. |
Title |
Origin of different deactivation of Pd/SnO2 and Pd/GeO2 catalysts in methanol dehydrogenation and reforming: a comparative study |
Type |
A1 Journal article |
Year |
2010 |
Publication |
Applied catalysis : A : general |
Abbreviated Journal |
Appl Catal A-Gen |
Volume |
381 |
Issue |
1/2 |
Pages |
242-252 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Pd particles supported on SnO2 and GeO2 have been structurally investigated by X-ray diffraction, (High-Resolution) transmission and scanning electron microscopy after different reductive treatments to monitor the eventual formation of bimetallic phases and catalytically tested in methanol dehydrogenation/ reforming. For both oxides this included a thin film sample with well-defined Pd particles and a powder catalyst prepared by incipient wetness impregnation. The hexagonal and the tetragonal polymorph were studied for powder GeO2. Pd2Ge formation was observed on all GeO2-supported catalysts, strongly depending on the specific sample used. Reduction of the thin film at 573K resulted in full transformation into the bimetallic state. The partial solubility of hexagonal GeO2 in water and its thermal structural instability yielded Pd2Ge formation at 473 K, at the cost of a structurally inhomogeneous support and Ge metal formation at higher reduction temperatures. Pd on tetragonal GeO2 entered a state of strong metalsupport interaction after reduction at 573673 K, resulting in coalescing Pd2Ge particles on a sintered and re-crystallized support, apparently partially covering the bimetallic particles and decreasing the catalytic activity. Pd2Ge on amorphous thin film and hexagonal GeO2 converted methanol primarily via dehydrogenation to CO and H2. At 573 K, formation of Pd2Sn and also PdSn occurred on the Pd/SnO2 thin film. Pd3Sn2 (and to some extent Pd2Sn) were predominantly obtained on the respective powder catalyst. Strong deactivation with increasing reduction temperature was observed, likely not based on the classical strong metalsupport interaction effect, but rather on a combination of missing active structural ensembles on Sn-enriched bimetallic phases and the formation of metallic -Sn. Correlations to Pd and its bimetallics supported on ZnO, Ga2O3 and In2O3 were also discussed. |
Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000279100700029 |
Publication Date |
2010-04-26 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0926-860X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.339 |
Times cited |
14 |
Open Access |
|
Notes |
Esteem 026019 |
Approved |
Most recent IF: 4.339; 2010 IF: 3.384 |
Call Number |
UA @ lucian @ c:irua:83927 |
Serial |
2522 |
Permanent link to this record |
|
|
|
Author |
Lorenz, H.; Turner, S.; Lebedev, O.I.; Van Tendeloo, G.; Klötzer, B.; Rameshan, C.; Pfaller, K.; Penner, S. |
Title |
Pd-In2O3 interaction due to reduction in hydrogen: consequences for methanol steam reforming |
Type |
A1 Journal article |
Year |
2010 |
Publication |
Applied catalysis : A : general |
Abbreviated Journal |
Appl Catal A-Gen |
Volume |
374 |
Issue |
1/2 |
Pages |
180-188 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Two different Pd/In2O3 samples including a thin film model catalyst with well-defined Pd particles grown on NaCl(0 0 1) supports and a powder catalyst prepared by an impregnation technique are examined by electron microscopy, X-ray diffraction and catalytic measurements in methanol steam reforming in order to correlate the formation of different oxide-supported bimetallic PdIn phases with catalytic activity and selectivity. A PdIn shell around the Pd particles is observed on the thin film catalyst after embedding the Pd particles in In2O3 at 300 K, likely because alloying to PdIn and oxidation to In2O3 are competing processes. Increased PdIn bimetallic formation is observed up to 573 K reduction temperature until at 623 K the film stability limit in hydrogen is reached. Oxidative treatments at 573 K lead to decomposition of PdIn and to the formation of an In2O3 shell covering the Pd particles, which irreversibly changes the activity and selectivity pattern to clean In2O3. PdIn and Pd2In3 phases are obtained on the powder catalyst after reduction at 573 K and 673 K, respectively. Only CO2-selective methanol steam reforming is observed in the reduction temperature range between 473 K and 573 K. After reduction at 673 K encapsulation of the bimetallic particles by crystalline In2O3 suppresses CO2 formation and only activity and selectivity of clean In2O3 are measured. |
Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000274869900023 |
Publication Date |
2009-12-18 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0926-860X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.339 |
Times cited |
55 |
Open Access |
|
Notes |
Esteem 026019 |
Approved |
Most recent IF: 4.339; 2010 IF: 3.384 |
Call Number |
UA @ lucian @ c:irua:81801 |
Serial |
3553 |
Permanent link to this record |
|
|
|
Author |
Van Aelst, J.; Philippaerts, A.; Turner, S.; Van Tendeloo, G.; Jacobs, P.; Sels, B. |
Title |
Heterogeneous conjugation of vegetable oil with alkaline treated highly dispersed Ru/USY catalysts |
Type |
A1 Journal article |
Year |
2016 |
Publication |
Applied catalysis : A : general |
Abbreviated Journal |
Appl Catal A-Gen |
Volume |
526 |
Issue |
526 |
Pages |
172-182 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Heterogeneous metal catalysts enable the direct conjugation of linoleic acid tails in vegetable oil to their conjugated linoleic acid (CIA) isomers. CIA-enriched oils are useful as renewable feedstock for the chemical industry and as nutraceutical. Up to now, a solvent-free process for conjugated oils without significant formation of undesired hydrogenation products was not existing. This work shows the design of Ru/USY catalysts able to directly conjugate highly unsaturated vegetable oils such as safflower oil in absence of solvent and hydrogen. Key is fast molecular transport of the bulky reagent and reactive product triglycerides in the zeolite crystal. A two-step zeolite post-synthetic treatment (with NH4OH and acetate salt) was applied to create the necessary mesoporosity. More open zeolite structures allow for a faster conjugation reaction, while securing a fast removal of the reactive conjugated triglycerides, otherwise rapidly deactivating through fouling and pore blockage by polymers. The best Ru/USY catalyst in this contribution is capable of producing exceptionally high yields of conjugated oils, containing up to almost 30 wt% conjugated fatty acid tails in safflower oil, at an initial production rate of 328 g(CLA) mL(-1) h(-1) per gram metal catalyst. (C) 2016 Elsevier B.V. All rights reserved. |
Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000384865600021 |
Publication Date |
2016-09-03 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0926-860x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.339 |
Times cited |
1 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 4.339 |
Call Number |
UA @ lucian @ c:irua:137242 |
Serial |
4383 |
Permanent link to this record |
|
|
|
Author |
van der Graaf, W.N.P.; Tempelman, C.H.L.; Hendriks, F.C.; Ruiz-Martinez, J.; Bals, S.; Weckhuysen, B.M.; Pidko, E.A.; Hensen, E.J.M. |
Title |
Deactivation of Sn-Beta during carbohydrate conversion |
Type |
A1 Journal article |
Year |
2018 |
Publication |
Applied catalysis : A : general |
Abbreviated Journal |
Appl Catal A-Gen |
Volume |
564 |
Issue |
564 |
Pages |
113-122 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
The deactivation of Sn-Beta zeolite catalyst during retro-aldolization and isomerization of glucose is investigated. Confocal fluorescence microscopy reveals that retro-aldolization of glucose in CH3OH at 160 degrees C is accompanied with the build-up of insoluble oligomeric deposits in the micropores, resulting in a rapid catalyst deactivation. These deposits accumulate predominantly in the outer regions of the zeolite crystals, which points to mass transport limitations. Glucose isomerization in water is not only accompanied by the formation of insoluble deposits in the micropores, but also by the structural degradation of the zeolite due to desilication and destannation. Enhanced and sustained catalytic performance can be achieved by using ethanol/water mixtures as the reaction solvent instead of water. |
Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000443669800012 |
Publication Date |
2018-07-21 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0926-860x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.339 |
Times cited |
25 |
Open Access |
OpenAccess |
Notes |
; This work was performed in the framework of the CatchBio programme and the Joint Scientific Thematic Research Programme funded by the The Netherlands Organization for Scientific Research (NWO) and the Chinese Ministry of Science and Technology. J.R.M. acknowledges the Dutch Science Foundation (NWO) for his personal VENI grant. ; |
Approved |
Most recent IF: 4.339 |
Call Number |
UA @ lucian @ c:irua:153715UA @ admin @ c:irua:153715 |
Serial |
5088 |
Permanent link to this record |
|
|
|
Author |
Wang, Y.-T.; Wu, S.-M.; Luo, G.-Q.; Tian, G.; Wang, L.-Y.; Xiao, S.-T.; Wu, J.-X.; Wu, A.; Wu, K.-J.; Lenaerts, S.; Yang, X.-Y. |
Title |
A core-shell confined Pd@TS-1 @meso-SiO2 catalyst and its synergy effect on styrene oxidation |
Type |
A1 Journal article |
Year |
2023 |
Publication |
Applied catalysis : A : general |
Abbreviated Journal |
|
Volume |
650 |
Issue |
|
Pages |
119016-6 |
Keywords |
A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL) |
Abstract |
Dual active sites from acidic zeolite and Pd are not only capable of catalyzing multiple type of reactions, but could also generate unique functions owing to the synergy between metals and acidic sites. However, there are only a few reports on the investigation of the synergy of acid/Pd dual sites in TS-1. Herein, TS-1 confined Pd catalyst with mesoporous silica shell (Pd@TS-1 @meso-SiO2) has been successfully synthesized and its synergy effect contributes to the enhanced conversion rate (19.2%) and selectivity (74.7%) on styrene oxidation. The interaction between Pd and TS-1 has been investigated by EPR and 1H NMR techniques, the experimental measurements show an obvious change in the signal distribution of weakly acidic terminal hydroxyls and hydrogen-bonding silanols. The schematic illustration of selective styrene oxidation in the model of Pd@TS-1 @meso-SiO2 is proposed to clarify the synergistic effect on styrene oxidation between TS-1 and Pd nanoparticles at an atomic-/nanoscale. |
Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
001015700000001 |
Publication Date |
2022-12-28 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0926-860x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
5.5 |
Times cited |
|
Open Access |
Not_Open_Access |
Notes |
|
Approved |
Most recent IF: 5.5; 2023 IF: 4.339 |
Call Number |
UA @ admin @ c:irua:197805 |
Serial |
8826 |
Permanent link to this record |