| Catalytic hydrocarbon oxidation and NOx reduction play crucial roles in emissions abatement. Since the complexity of these processes has limited the fundamental understanding required for rapid progress, their accurate characterization continues to be an active area of research. In this work, classical mean field and quantum modeling, as well as a combination of experimental techniques are used to explore these processes at the molecular level. Chemisorption of the family of NOx adsorbates on the MgO surface involves a number of molecular level interactions which can be qualitatively understood in terms of Lewis acid and base interactions. Chemisorption is optimized when donor/acceptor adsorbate components interact with complementary surface sites. Additionally, one-electron oxidation or reduction between co-adsorbed neighbors produce greatly enhanced Lewis acid base coordination with the surface. Experimental TPD which focused on establishing a molecular-level understanding of adsorption and possible surface reactions of NO and NO2 on MgO(100) were performed to provide an additional perspective on the characteristics predicted from quantum models. As part of these fundamental mechanistic studies, mean field models were used to extract molecular reaction mechanisms for the oxidation of carbon monoxide on the Pt(111) surface. These studies resulted in the development of a unified coupled differential equation model, which includes significant insight in the role of coverage in reaction energetics. Taken together, these results have established important new understanding in the fields of catalytic NOx reduction and CO oxidation through a unique coupling of modeling and experiments. This combination of techniques has made accessible the fundamental understanding of even complex reaction catalytic reaction systems. |
