NO decomposition in non-reducing atmospheres. Technical progress report, December 1996--February 1997

During this quarter, the studies with Co(II) ion exchanged erionite were continued. Last quarter, it was shown that diffuse reflectance spectroscopy (DRS) studies indicated that the Co(II) cations can occupy three different sites in the erionite structure. The occupancy depended upon the Co(II) content of the erionite and upon the temperature of dehydration. Semi-quantitative occupancy numbers have now been derived and are presented here. Adsorption studies have been continued using CO and ethylene to probe whether the Co(II) cations in all of these sites are accessible to ligands, such as CO and ethylene. It is shown that Co(II) cations that are designated as Species 1 and 3, with optical bands centered at {approx} 17,000 cm{sup -1} and {approx} 24,000-25,000 cm{sup -1}, respectively, are located in sites that are accessible to guest molecules. In contrast, Co(II) cations designated as Species 2, characterized by an optical band centered at z 19,000 cm-{sup 1}, are not accessible to guest molecules