NO decomposition in non-reducing atmospheres. Technical progress report, December 1994--February 1995

The overall goal of this research is to establish the fundamental science needed to develop catalysts that will exhibit high activity and selectivity in the decomposition of NO into N{sub 2} and O{sub 2}. This project is centered on the preparation, characterization, and testing of transition metal exchanged catalysts, especially Co(III) zeolites. Additional Co(II) exchanged A zeolite samples have been prepared in aqueous solution at pH = 5.0-6.1 that contain different exchange levels of Co(II). Some of these have been analyzed for Na and Co contents by chemical methods and by X-ray photoelectron spectroscopy. It was shown that preparation of the samples by ion exchange between pH {approx}6 and 7 tended to give stoichiometric ion exchange of Co(II) for Na{sup +}. However, ion exchange at lower pH tended to lead to exchange with H{sup +} while ion exchange at higher pH tended to lead to the presence of excess Co(H), probably by precipitation of a basic Co phase. Systematic analyses of Na A zeolite, CO(II) A zeolites, and Co(II)/Ce(III) A zeolites, as well as Na X zeolite, Na Y zeolite, and Na mordenite for comparison purposes, have been carried out by X-ray photoelectron spectroscopy and Auger spectroscopy methods. Complete data analysis has not yet been carried out, but trends in some parameters have been noted, e.g. the relative intensity of the O KL{sub 2,3}L{sub 2,3} line in the O ls spectral region increases as the Si Al ratio of the Na zeolites increases