9311876 Oyama This is a study of the reactions of ozone on transition-metal oxides. Ozone decomposition on oxide catalysts is observed to determine the effects of oxide-support and oxide-oxide interactions; kinetics measurements are made for the most active systems. Adsorption/desorption properties of the oxides are studied using temperature-programmed techniques; the mode of ozone adsorption is studied using isotope scrambling. Dispersion, phase composition, and surface intermediates in single-component and binary catalytic systems are determined using X-ray diffraction and laser Raman spectroscopy. In situ techniques such as the Hall effect, quartz-crystal microbalance, and surface charge measurements are employed to show whether p-type oxides are more active catalysts and whether the superoxide ion (02-) is a possible reaction intermediate. Finally, the reactivities of ozmne/oxygen mixtures with ethanol or propylene are observed. It is "common knowledge" that transition-metal oxides can catalyze reactions and decomposition of ozone, but these systems have never been studied systematically. This study has not only fundamental significance, but also practical importance both in issues about the environmental fate of ozone and in the development of technology to control ozone levels in environmental or occupational settings. ***

Project Start
Project End
Budget Start
1994-07-01
Budget End
1998-06-30
Support Year
Fiscal Year
1993
Total Cost
$250,000
Indirect Cost
City
Blacksburg
State
VA
Country
United States
Zip Code
24061