The front cover artwork for Issue 3/2014 is provided by the Inorganic Chemistry and Catalysis group of Utrecht University. The image shows the concept of synchrotron-based IR and UV/Vis microspectroscopy monitoring a catalytic reaction on a single SAPO-34 crystal and the obtained spatially resolved information on the retained hydrocarbon species and crystal accessibility. See the Full Paper itself on http://dx.doi.org/10.1002/cctc.201300962.
123In situ microspectroscopy can seem abstruse to catalyst scientists less familiar with these characterization tools, who may regard this approach as a “black box”. With this cover picture, we wanted to shed some light onto this black box and illustrate our approach for a more comprehensive understanding of catalytic processes. We depict the interaction of a single catalyst particle with both visible and infrared light, shown as white and red beams, respectively. The harvested spatially resolved chemical information is represented as projections on the two screens.
What prompted you to investigate this topic?
There have been very limited mechanistic studies on methanol-to-olefins (MTO) and ethanol-to-olefins (ETO) processes in single catalyst particles that employ space-resolved in situ spectroscopy. We have learnt from our recent work (Q. Qian et al., Chem. Eur. J. 2013, 19, 11204) that MTO and ETO processes follow distinct reaction pathways for the formation of both active and deactivating hydrocarbon species. In our current research, we aimed to understand better the entangled chemistry and molecular accessibility of individual crystals during different MTO and ETO reaction stages. For this purpose, we combined synchrotron-based IR and UV/Vis microspectroscopy with isotopic labeling experiments.
What aspect of the project do you find most exciting?
We consider the isotopic switching experiments combined with IR microspectroscopy the most novel aspects of this research. This powerful approach elucidates the nature and reactivity of the hydrocarbon species formed and the accessibility of the different types of hydrocarbons during the different stages of MTO and ETO processes. We envisage that this methodology will give new insights into other catalyst systems.
This research was funded by the Dutch National Research School Combination Catalysis, the Netherlands Organization for Scientific Research (CW-NWO Top grant), and the Deanship of Scientific Research of King Abdulaziz University (grant No. T-002-431). We acknowledge SOLEIL (Paris, France) for access to the synchrotron radiation facilities (proposal No. 20120471) and would like to thank Dr. Frédéric Jamme and Dr. Paul Dumas of Beamline SMIS for their kind help and discussions. Dimitrije Cicmil and Dr. Christoph Sprung (Utrecht University) are thanked for their help during the synchrotron-based IR measurements. Dr. Jan Kornatowski (Max-Planck-Institute für Kohlenforschung, Mülheim an der Ruhr, Germany) is acknowledged for providing the SAPO-34 crystals. J.R.-M. also acknowledges NWO for his VENI grant.