The role of surface groups in catalytic reactions over ZIF-8 films
University of San Diego
Chemistry and Biochemistry
Zeolitic Imidazolate Frameworks (ZIF) have gained notoriety of late for catalytic activity in reactions such as cycloaddition, transesterification, Knoevenagel reactions, and Friedel Crafts acylations. However, the exact role of Lewis acidic and basic surface groups in these reactions remains unclear. In this study, direct characterization of surface groups of ZIF-8 was employed during the adsorption and reaction of gases involved in the above reactions with a specific emphasis on the cycloaddition of epichlorohydrin and CO2. Using a combination of X-ray photoelectric spectroscopy (XPS) and temperature programmed reaction spectroscopy (TPRS), the role of outer surface groups of ZIF-8 was compared to that of inner pore sites during the aforementioned reactions. ZIF-8 nanoparticle films were mounted in a UHV chamber in these studies to facilitate the study of surface group interactions. An understanding of the role of the surface groups in catalysis is important in developing ZIFs as more effective and efficient catalysts.