Surface Science Approach to the Molecular Level Integration of the Principles in Heterogeneous, Homogeneous, and Enzymatic Catalysis

Abstract

Heterogeneous, homogeneous, and enzymatic catalysis have generally been treated and studied as three separate fields. However all three fields have many aspects that unify them, therefore it is useful to study catalysts from each field in similar manners. Heterogeneous catalysts have been studied extensively under reaction conditions to monitor dynamic changes that occur during catalytic reactions, their atomic and molecular structure, and composition and oxidation state with high spatial and time resolution. The techniques used to monitor these catalysts include sum frequency generation vibrational spectroscopy, high pressure scanning tunneling microscopy, and ambient pressure X-ray photoelectron spectroscopy. In order to use these techniques to study homogeneous catalysts and enzymes under reaction conditions, we have heterogenized homogeneous catalysts by encapsulating small metal clusters in dendrimers and immobilized enzymes through the use of DNA tethers. By studying all three fields under reaction conditions with the same techniques we aim to show that heterogeneous, homogeneous, and enzymatic catalysts all behave similarly at the molecular level.