The University of Massachusetts Amherst
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ChE MS Defense: Shreya Thakkar, Chromatographic Dynamic Chemisorption"


Tuesday, December 14, 2021 - 11:00am


via Zoom (please email for a link)


Reaction rates of catalytic cycles over supported metal catalysts are normalized by the exposed metal atoms on the catalyst surface, reported as site time yields which provide a rigorous standard to compare distinct metal surfaces. Defined as the fraction of exposed metal surface atoms to the total number of metal atoms, it is important to measure the dispersion of supported metal catalysts to report standardized rates for kinetic investigations. Multiple characterization techniques such as electron microscopy, spectroscopy and chemisorption are exploited for catalyst dispersion measurements. While effective, electron microscopy and spectroscopy are not readily accessible due to cost and maintenance requirements. Commercial instruments therefore typically rely on chemisorption measurements, but can be cost prohibitive nonetheless, hindering the ability of catalysis research to report rigorous measures of activity. Thus, a dispersion measurement technique based on gas chromatography equipment ubiquitous in catalysis research is proposed, devised with the goal of developing a readily accessible and inexpensive dispersion measurement tool. Based on the principle of dynamic carbon monoxide chemisorption, where exposed metal surface area is estimated based on the amount of adsorbed carbon monoxide, the proposed technique is developed across a range of group VIII metal catalysts varying in weight loading and support identity.

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