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9 results on '"Parmentier, Tanja E."'

4. Tailoring and visualizing the pore architecture of hierarchical zeolites

Author

Wei, Ying, Parmentier, Tanja E., de Jong, Krijn P., Zecevic, Jovana, Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Sub Inorganic Chemistry and Catalysis, and Inorganic Chemistry and Catalysis

Subjects
Mass transport, Materials science, HIGH-SILICA ZEOLITES, TRANSMISSION ELECTRON-MICROSCOPY, Synthesis methods, DIRECTED SYNTHESIS, Nanotechnology, Pore system, General Chemistry, MOLECULAR-SIEVES, 3d microscopy, Characterization (materials science), CATALYTIC PERFORMANCE, MFI ZEOLITE, DIFFERENT ALUMINUM CONTENT, CONFINED SPACE SYNTHESIS, SINGLE-CRYSTALS, Porosity, MESOPOROUS ZSM-5 ZEOLITE
Abstract

Recently the concept of hierarchical zeolites invoked more explicit attention to enhanced accessibility of zeolites. By realizing additional meso-/macroporosity with the intrinsic microporosity of zeolites, a hierarchical pore system arises which facilitates mass transport while maintaining the zeolite shape selectivity. A great number of synthesis strategies have been developed for tailoring the pore architecture of hierarchical zeolites. In this review, we give a general overview of different synthesis methods for introduction of additional porosity. Advantages and limitations of these different synthesis approaches are addressed. The assessment of pore structure is essential to build the link between the zeolite pore structure and its functionality. A variety of 2D and 3D microscopy techniques are crucial to visualize the hierarchical pore structure, providing unique and comprehensive information that, however, should be linked to the results of bulk characterization techniques as much as possible. The microscopy techniques are classified and discussed according to the different probes used, such as optical light, X-rays and electrons. Representative work is reviewed to elucidate the capability of each technique and their drawbacks.

Published
2015

5. Support Functionalization To Retard Ostwald Ripening in Copper Methanol Synthesis Catalysts

Author

van den Berg, Roy, Parmentier, Tanja E., Elkjaer, Christian F., Gommes, Cedric J., Sehested, Jens, Helveg, Stig, de Jongh, Petra E., de Jong, Krijn P., van den Berg, Roy, Parmentier, Tanja E., Elkjaer, Christian F., Gommes, Cedric J., Sehested, Jens, Helveg, Stig, de Jongh, Petra E., and de Jong, Krijn P.

Abstract

A main reason for catalyst deactivation in supported catalysts for methanol synthesis is copper particle growth. We have functionalized the support surface in order to suppress the formation and/or transport of mobile copper species and thereby catalyst deactivation. A Stober silica support was functionalized by treatment with aminopropyltriethoxysilane, which introduces aminopropyl groups on the surface. Copper was deposited on both unfunctionalized and functionalized Stober silica via incipient wetness impregnation with aqueous copper nitrate solutions followed by drying and calcination. Similar particle size distributions (1-5 nm) were obtained for both supports by changing the flow of N-2 to a flow of 2% NO/N-2 during calcination of the unfunctionalized and amine-functionalized silica, respectively. The effect of support functionalization with aminopropyl groups was an increased stability in the methanol synthesis reaction (40 bar, 260 degrees C, 23% CO/7% CO2/60% H-2/10% Ar, 3% COx conversion) due to more limited copper particle growth as determined by transmission electron microscopy (TEM). Changing the interparticle distance did not have an influence on the deactivation rate, while the addition of few very large copper particles did, indicating that Ostwald ripening was most probably the dominant particle growth mechanism for these samples. In situ TEM images showed the contact angle between the reduced copper particles and the support. As shape and size was similar on silica as on amine-functionalized silica, the thermodynamic stability of the copper particles was unaltered. The driving force for copper particle growth was thus unchanged upon functionalization. We therefore suggest that Ostwald ripening in methanol synthesis catalysts was retarded by inhibiting the transport of copper species over the support surface. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) revealed a decrease in the number of surface groups (hydroxyl, methoxy

Published
2015

6. Tailoring and visualizing the pore architecture of hierarchical zeolites

Author

Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Wei, Ying, Parmentier, Tanja E., de Jong, Krijn P., Zecevic, Jovana, Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Wei, Ying, Parmentier, Tanja E., de Jong, Krijn P., and Zecevic, Jovana

Published
2015

7. Effect of support surface treatment on the synthesis, structure, and performance of Co/CNT Fischer-Tropsch catalysts

Author

Inorganic Chemistry and Catalysis, Sub Inorganic Chemistry and Catalysis, Eschemann, Thomas O., Lamme, Wouter S., Manchester, Rene L., Parmentier, Tanja E., Cognigni, Andrea, Ronning, Magnus, de Jong, Krijn P., Inorganic Chemistry and Catalysis, Sub Inorganic Chemistry and Catalysis, Eschemann, Thomas O., Lamme, Wouter S., Manchester, Rene L., Parmentier, Tanja E., Cognigni, Andrea, Ronning, Magnus, and de Jong, Krijn P.

Published
2015

8. Support Functionalization To Retard Ostwald Ripening in Copper Methanol Synthesis Catalysts

Author

Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, van den Berg, Roy, Parmentier, Tanja E., Elkjaer, Christian F., Gommes, Cedric J., Sehested, Jens, Helveg, Stig, de Jongh, Petra E., de Jong, Krijn P., Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, van den Berg, Roy, Parmentier, Tanja E., Elkjaer, Christian F., Gommes, Cedric J., Sehested, Jens, Helveg, Stig, de Jongh, Petra E., and de Jong, Krijn P.

Published
2015

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