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11.
Dimitrios K. Pappas Dr. Elisa Borfecchia Dr. Michael Dyballa Dr. Kirill A. Lomachenko Andrea Martini Dr. Gloria Berlier Dr. Bjørnar Arstad Prof. Carlo Lamberti Prof. Silvia Bordiga Prof. Unni Olsbye Prof. Stian Svelle Dr. Pablo Beato 《ChemCatChem》2019,11(1):621-627
Cu-exchanged zeolites with the Ferrierite topology were investigated in the direct CH4 to CH3OH conversion. Samples with a systematic compositional variation in terms of Na/Al and Cu/Al ratios where synthesized by liquid ion exchange. The presence of Na is observed to be beneficial for the Cu exchange and thereby higher Cu loadings were achieved. The overall performance of Cu-FER samples depends on Cu loading as well as the conditions of the reaction. Elevated O2 activation temperature as well as long CH4 loading times are proven to enhance the CH3OH yield of the Cu-FER sample with Cu/Al=0.2. In addition, the productivity depends on the Cu/Al ratio, at low values the sample is almost inactive indicating a Cu threshold that needs to be surpassed. We employed X-ray absorption and IR of adsorbed CO spectroscopies in order to rationalize the performance as well as the effect of Cu/Al ratio. From the in situ spectroscopies we ultimately establish structure-activity relationships between the reducibility of Cu species and the CH3OH yield. 相似文献
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Stian Ramsnes Helge Bvik Larsen Gunnar Thorkildsen 《Journal of Applied Crystallography》2019,52(1):214-218
A comprehensive Mathematica package for crystallographic computations, MaXrd, has been developed. It comprises space‐group representations based on International Tables for Crystallography, Vol. A, together with scattering factors from XOP and cross sections from xraylib. Featured functionalities include calculation of structure factors, linear absorption coefficients and crystallographic transformations. The crystal data used by MaXrd are normally generated from external .cif files. The package comes with a dynamic documentation seamlessly integrated with the Mathematica system, including code, examples, details and options. From the onset, minimal Mathematica experience is required to make use of the package. It may be a helpful supplement in research and teaching where crystallography and X‐ray diffraction are essential. Although Mathematica is a proprietary software, all the code of this package is open source. It may easily be extended to cover user‐specific applications. 相似文献
13.
Svelle S Olsbye U Lillerud KP Kolboe S Bjørgen M 《Journal of the American Chemical Society》2006,128(17):5618-5619
Despite their vital roles in the catalytic cycle for toluene disproportionation, diphenylmethane (DPM)-type compounds have never been directly detected or proved to be true reaction intermediates from experimental techniques. In this report, we provide unprecedented insights into the DPM-mediated reaction mechanism, by demonstrating the build-up of DPM species inside the zeolite pores and following their decomposition. It can be stated that, despite their bulkiness, (di)methylated DPM species may indeed be formed at high concentrations in the ZSM-5 channels when toluene is reacted. The dimethyl-DPM species are unstable when present in the zeolite voids and decompose under a concomitant evolution of xylene at 200 degrees C. 相似文献
14.
The methylation of propene and toluene with dimethyl ether has been studied using both experimental and theoretical methods, and the results are compared with results obtained for methylation with methanol. The results indicate that the nature of the methylation reaction mechanisms is very similar for both methylation agents. Both experiment and theory show that dimethyl ether is a slightly more reactive methylating agent than methanol. 相似文献
15.
Gerard Boix-Lemonche Richard M. Nagymihaly Essi M. Niemi Natasha Josifovska Stian Johansen Morten C. Moe Hanne Scholz Goran Petrovski 《Macromolecular bioscience》2023,23(7):2200422
Injury of the cornea is a complex biological process. Regeneration of the corneal stroma can be facilitated by the presence of mesenchymal stromal cells (MSCs) and application of tissue equivalents. A new tissue-engineering strategy for corneal stroma regeneration is presented using cellularized 3D bioprinted hydrogel constructs implanted into organ cultured porcine corneas using femtosecond laser-assisted intrastromal keratoplasty. The ex vivo cultured, MSC-loaded 3D bioprinted structures remain intact, support cell survival, and contain de novo synthesized extracellular matrix components and migrating cells throughout the observation period. At day 14 postimplantation, the cellularized tissue equivalents contain few or no cells, as demonstrated by optical coherence tomography imaging and immunofluorescent staining. This study successfully combines a laboratory-based method with modern, patient-care practice to produce a cell-laden tissue equivalent for corneal implantation. Optimal bioink composition and cellularization of tissue equivalents are essential in fine-tuning a method to promote the current technique as a future treatment modality. 相似文献
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