Subsequent projects
Friedrich-Alexander-University
of Erlangen-Nuremberg
Chemical Reaction Techniques (CRT)
University of California, Berkeley
Department of Chemical Engineering
Characterization of Supported Ionic Liquid Phase (SILP) catalysts by in-situ spectroscopy methods and catalytic experiments
The goal of this joint project is the detailed understanding of composition-performance-relations of novel, supported ionic liquid phase (SILP) catalysts. These hybrid materials possess high potential for scientific and industrial application as they combine the advantages of both homogeneous and heterogeneous catalysts. Following the results obtained during the initial funding period, in-situ spectroscopic techniques (e.g. FTIR and solid-state NMR) are highly suitable to study the exact composition and structure of SILP catalysts. However, the desired catalyst features such as high activity, selectivity and stability depend on the interplay of several factors. Therefore, advanced spectroscopic techniques (incl. STEM-EELS) in combination with catalytic experiments shall be utilized to obtain profound understanding of the relations between composition and performance of SILP catalysts. Attention will be paid to the purposeful optimization of SILP materials for specific applications as well as to the influence of CO2 on the catalyst molecular structure and behavior.
Primary project: Characterization of Supported Ionic Liquid Phase (SILP) catalysts by in-situ spectroscopy methods and catalytic experiments
Final Report
The goal of this joint project was to gain a detailed understanding on structure-property and structure-performance relationships in recently developed Supported Ionic Liquid and Supported Molten Salt (SMS) catalysts. For this purpose, classical Pt on AlOx catalysts were coated with different molten salts and the resulting materials were tested in methanol steam reforming and water-gas-shift (WGS) catalysis using continuous fixed-bed reactors at the Institute for Chemical Reaction Engineering at FAU in Erlangen. It could be demonstrated that the salt coating leads to strongly enhanced catalytic activity and selectivity. To elucidate the molecular origin of these remarkable effects, several spectroscopic methods (DRIFTS, solid-state NMR) were successfully applied.[1,2] These studies highlighted a complex interaction of several factors, such as salt hygroscopicity, salt basicity, support modification by the salt coating and salt-metal electronic exchange. In the light of the industrial significance of the excellent performance of these novel salt-coated catalysts, a more detailed understanding of these effects and their interplay was highly desirable.
Thus, our BaCaTeC activities aimed for a much more detailed investigation of the catalytic surface after the salt coating process and after the catalytic operation of salt-coated catalysts. For this purpose, my co-worker, MSc Matthias Kusche, performed transmission electron microscopy (HAADF-STEM) in combination with X-ray spectroscopy (EDS) at the National Center for Electron Microscopy in Berkeley, California. We had to apply for the respective measurement time at the Berkeley instrument in competition with other users. The experiments were carried out between early June and late July 2014. The experimental work was strongly supported by Prof. Alexis Bell, Department of Chemical Engineering, University of California. These investigations demonstrated that the salt-coated Pt-catalysts are completely covered by a layer of potassium salt with clear evidence for strong Pt-K interactions. The results of these very successful studies were published in a high-quality peer-reviewed journal, with our Berkeley colleague, Dr Karen Bustillo, as co-author.[3] All results are in-line with earlier hypotheses from our Erlangen work and confirm the latter impressively.
[1] M. Kusche, F. Enzenberger, S. Bajus, H. Niedermeyer, A. Bösmann, A. Kaftan, M. Laurin, J. Libuda, P. Wasserscheid, Enhanced activity and selectivity in catalytic methanol steam reforming by basic alkali salt coatings, Angewandte Chemie Int. Ed., 2013, 52(19), 5132-5136.
[2] M. Kusche, F. Agel, N. Ni Bhriain, A. Kaftan, M. Laurin, J. Libuda, P. Wasserscheid, Methanol steam reforming promoted by molten-salt modified platinum on alumina catalysts, ChemSusChem, 2014, 7(9), 2516-2526.
[3] M. Kusche, K. Bustillo, F. Agel, P. Wasserscheid, Highly effective Pt-based water-gas shift catalysts through a surface modification with alkali molten salts, ChemCatChem, 2015, DOI: 10.1002/cctc.201402808, in press.