Nature of chemisorbed species on metal oxide surfaces. Electron transfer and bond-breaking processes

Abstract

Highly ionic insulator oxides, in particular MgO, can be prepared in high surface area form possessing many surface defect sites. The nature of these thermally robust defects are either structural (edges, planes, kinks, cation and anion vacancies) or electronic (electron excess or deficient sites). Extremely basic, electron rich sites are capable of strongly interacting with chemisorbing molecules. Proton abstraction, electron transfer, molecular oligomerization, base condensation, and radical trapping reactions have been observed with various adsorbing organic molecules. Adsorbed species can be readily detected with appropriate spectroscopic tools. Further technological use of thermally activated MgO and other oxides appear promising, especially in such areas as selective hydrocarbon H-D exchange catalysts, and destructive adsorbants for air purification purposes.