A design is presented for a versatile transmission infrared cell that can interface with an external vacuum manifold to undergo in situ gas treatments and receive controlled doses of various adsorbates and probe molecules, allowing characterization of heterogeneous catalyst surfaces in order to identify and quantify active sites and adsorbed surface species. Critical design characteristics include customized temperature control for operation between cryogenic and elevated temperatures (100-1000 K) and modified Cajon fittings for operation over a wide pressure range (10-2-103 Torr) that eliminates the complications introduced when using sealants or flanges to secure cell windows. The customized, hand-tightened Cajon fittings simplify operation of the cell compared to previously reported designs, because they allow for rapid cell assembly and disassembly and, in turn, replacement of catalyst samples. In order to validate the performance of the cell, transmission infrared spectroscopic experiments are reported to characterize the Brønsted and Lewis acid sites present in H-beta and H-mordenite zeolites using cryogenic adsorption of CO (<150 K).
Bibliographical noteFunding Information:
Support for this research was provided by the Purdue Process Safety and Assurance Center (P2SAC), and the U.S. Department of Energy, Office of Basic Energy Sciences, Catalysis Science Grant No. DE-FG02-03ER15408. We would like to thank David Taylor for design and fabrication of the temperature controller for the IR cell. We would also like to thank James R. Zimmerman in the Department of Chemistry at Purdue University for developing schematics of the temperature controller. Additionally, we thank Kris L. Davis and Verlin D. Lindley of Research Machining Services at Purdue University for design and fabrication of the temperature-controlled chamber for the IR cell.
© 2016 Author(s).