| AVS 66th International Symposium & Exhibition | |
| Fundamental Discoveries in Heterogeneous Catalysis Focus Topic | Thursday Sessions |
| Session HC-ThP |
| Session: | Fundamental Discoveries in Heterogeneous Catalysis Poster Session |
| Presenter: | John Newman, Physical Electronics |
| Authors: | J.G. Newman, Physical Electronics D.M. Carr, Physical Electronics D. Paul, Physical Electronics L. Swartz, Physical Electronics M. Di Mare, Scientific Design Company, Inc. W. Suchanek, Scientific Design Company, Inc. |
| Correspondent: | Click to Email |
Alumina supported silver catalysts have been used for decades for the direct oxidative conversion of ethylene to ethylene oxide. Ethylene oxide is used in many cleaning and sterilizing products; however, its major industrial application is in the production of ethylene glycol used in the generation of antifreeze, polyesters, liquid coolants and solvents. Global production of ethylene oxide is estimated to grow to 28 million metric tons in 2019 at an estimated market value of over $48 billion (1, 2).
Due to the huge size of this market, incremental improvements in the efficiency and longevity of the catalyst can be very beneficial. Many companies continuously explore ways in which to improve the various aspects of the catalyst system – the physical and chemical properties of the catalyst, the preparation technology, and the reaction conditions.
In this investigation, three surface sensitive (outermost ≤ 5 nm) techniques, X-ray Photoelectron Spectroscopy (XPS), Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS), and Auger Electron Spectroscopy (AES) were used to study the changes that occur between fresh and aged Cs-promoted, alumina-supported Ag catalyst samples. XPS provided insights into the overall surface concentrations of the elements present as well as chemical state changes that occurred during aging. TOF-SIMS was used to detect and spatially locate elements at concentrations often too low to detect with XPS or AES, and AES high magnification elemental mapping and small area spectroscopy were used to study the localized elemental changes that occurred between fresh and aged catalyst samples. Information gained from these experiments provides valuable insights on the physical and chemical transformations taking place during aging of the catalyst. This information can then be used to suggest further modifications to improve the performance of the catalyst system.
References
1. PR Newswire, Global Ethylene Oxide Market Report 2018 - Forecast to 2023: The Growing Demand for PET Bottles from the Packaging Industry, Nov 26, 2018
2. Business Wire, Global Ethylene Oxide Market Report By Application, April 24, 2018