Cooperative interactions in chemisorption on oxides

GEOC 160

W. F. Schneider, Physical and Environmental Sciences, Physical and Environmental Sciences, Ford Motor Company, 2101 Village Road, MD 3083/SRL, Dearborn, MI 48121-2053
Adsorption on oxide surfaces is fundamental to many aspects of environmental chemistry and catalysis. Despite this importance, the chemical concepts underlying oxide adsorption are not as well developed as for metal surfaces. In our work, density functional theory methods are being used to elucidate the adsorption chemistry of species particularly relevant to atmospheric chemistry and environmental emissions control, including CO2, SOx, and NOx, on main group and transition metal oxides. We find that this chemistry can be understood in terms of a combination and acid/base and charge transfer interactions which, in some cases, can lead to dramatic "cooperative" enhancements in adsorption. These interactions depend sensitively on the electronic structure of the oxides and the properties of the adsorbates. In particular, differences in behavior among different oxides and different adsorbates can potentially be exploited in the design of more effective and selective emissions control materials.