The overall objective of the research in the Madix group is to further the understanding of the catalytic reactivity of surfaces on the atomic and molecular scale. In general, heterogeneously catalyzed reactions proceed through a series of elementary steps, (1) adsorption of reactants, (2) reaction of adsorbed, rate-determining reactive intermediates, and (3) desorption of products. The rate of each of these steps depends on the nature of the surface - its geometric and electronic properties. It is then clear that the catalytic activity of a surface, as measured by the rate of rate determining step in the overall reaction, and the catalytic selectivity, as measured by the rate of reaction to form the desired product, depends in detail on the surface itself.
In this laboratory we are studying fundamental aspects of all three of these processes. We are engaged in research on both metal and metal oxide catalysts. We use modern methods of ultrahigh vacuum physics to examine reactivity on well-defined single crystal surfaces, using a variety of spectroscopic tools to follow the reactions. Recently much of our work has focused on imaging reactive intermediates with scanning tunneling microscopy.