Site-selective surface reactions: Hydrocarbon oxidation processes on oxidized Mo(110)

The site specificity for elementary steps important in hydrocarbon oxidation are investigated on oxidized Mo(110). Our studies illustrate how detailed mechanistic information is obtained about surface reactions by separating complex problems into elementary reaction steps on well-defined materials. This methodology is particularly powerful for the study of fundamental structure-reactivity relationships, including issues of site specificity. Methods for synthesizing and characterizing oxidized surfaces with specific types of oxygen coordination are described to demonstrate how a model system can be constructed. We have focused on the C-O bond formation step in the oxidation of methane via our investigations of methyl radical reactions with surface oxygen and the microscopic reverse, methyl evolution from adsorbed methoxy. A combination of infrared and electron energy loss spectroscopies is used to identify specific intermediates on the surface. Our results are discussed in terms of hydrocarbon oxidation on MoO(3)-based materials.