Friday, November 19 at 12:00pm to 1:00pmVirtual Event
Monitoring the Surfaces of Materials in Action
Israel Wachs, G. Whitney Snyder Professor, Chemical and Biomolecular Engineering Director, Operando Molecular Spectroscopy and Catalysis Research Lab
Zoom link: https://lehigh.zoom.us/j/91985375211
Catalysts account for production of products that contribute to ~25% of a western country’s GDP (fuels, chemicals, plastics, pollution control, pharmaceuticals, etc.). Catalysts accelerate chemical reactions to the desired products and minimize wasteful byproducts (e.g., CO2 emissions, etc.). Approximately 90% of industrial chemical reactions involve catalysts. Homogeneous catalysts, catalysts that are soluble in a solvent, find application for liquid phase catalysis and heterogeneous catalysts, catalysts that are solids and find application for catalysis occurs at gas-solid and liquid-solid interphases. Thus, heterogeneous catalysts perform catalysis at their solid surfaces (the outermost surface layer, ~0.3 nm). It is critical to be able to determine the relationships between the catalytic surface sites and their activity/selectivity performance since such fundamental knowledge can guide the rational design of improved and advanced catalytic materials.
This presentation will show how multiple spectroscopic techniques have been applied to monitor and establish fundamental catalytic structure-activity/selectivity relationships under reaction conditions (in situ and operando spectroscopy). The focus of the Wachs lab has been on advancing the catalysis science of mixed oxide catalysts with the application of Raman, IR, UV-Vis, atmospheric pressure XPS, Low Energy Ion Scattering (LEIS) spectroscopy, as well as other molecular spectroscopic techniques available at national labs (NMR, EPR and X-ray Absorption Spectroscopy (XAS)). Several examples will be highlighted to demonstrate how such research is being performed to develop new reaction models of catalysis.
Israel E. Wachs received his undergraduate education at The City College of The City University of New York where he graduated with a B.E. (ChE) and continued his graduate ChE education at Stanford University under the mentorship of Professor Robert J. Madix in the area of surface science, and graduated with a PhD (ChE). Israel joined Exxon Research & Engineering Company in their Corporate Research Labs after graduate school. At Exxon, he was involved with many different catalytic technologies over the years One of his inventions on the selective oxidation of o-xylene to phthalic anhydride by promoted supported V2O5/TiO2 catalysts became the leading international industrial catalyst for this technology and is still used around the world. He departed Exxon for academia at the end of 1986.
Israel joined the Chemical Engineering Department of Lehigh University in January 1987. At Lehigh, he set up a world-class catalysis research laboratory focusing on mixed metal oxide catalytic materials and their characterization under reaction conditions (in situ and operando molecular spectroscopy). These studies have established the foundation for the molecular/electronic structure – activity/selectivity relationships that are developing a unified model of mixed metal oxide catalysts and guiding the rational design of novel and improved catalysts. The research performed by the Wachs group is well known around the world and reflected by the many national and international honors and his publications are extensively cited in the literature (~40,000 citations and an H-index of >110).
The current focus of the Wachs catalysis group is to develop catalyst characterization techniques under reaction conditions, referred to as operando spectroscopy in the recent literature, and apply them to determine how high profile catalytic systems actually function. The term operando spectroscopy implies that the catalyst characterization information is being conducted simultaneously with online product analysis to allow for establishing direct structure-activity/selectivity relationships. Along these lines, the Wachs group has developed instrumentation that can simultaneously obtain Raman, IR, UV-vis and TPSR spectroscopic information and product analysis with an online mass spectrometer/GC system. This cutting-edge instrument is allowing the Wachs catalysis research group to rapidly develop fundamental molecular/electronic structure – catalytic activity/selectivity relationships for many different catalytic materials and reactions that are leading to development of advanced catalysts.