Harold, Michael P.2016-09-062016-09-06May 20142014-05Portions of this document appear in: Perng, Charles CY, Vencon G. Easterling, and Michael P. Harold. "Fast lean-rich cycling for enhanced NO x conversion on storage and reduction catalysts." Catalysis Today 231 (2014): 125-134.http://hdl.handle.net/10657/1561Lean NOx (NO + NO2) reduction was carried out using rapid periodic injection of C3H6 over a NOx storage and reduction (NSR) monolith catalyst containing Pt/Rh/BaO/CeO2/Al2O3. The effects of injection speed, feed temperature, rich phase composition, lean phase duration, and feed concentration of CO2 were systematically studied to highlight distinct performance characteristics at faster injection frequencies. Increased NOx and C3H6 conversions were achieved using high frequency injection. The detrimental effects of barium nitrate decomposition at high temperatures and barium carbonate formation were also found to be less significant using rapid pulsing. In addition, a prolonged approach to cyclic steady state was observed for high frequency operation. The results are indicative of a qualitative mechanistic change and suggest the generation of reactive “HCxNyOz” intermediate species that enable improved performance over traditional NSR cycling.application/pdfengThe author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. UH Libraries has secured permission to reproduce any and all previously published materials contained in the work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s).NOxPlatinumReductionNOx storageNOx reductionPropylenePeriodic operation2016-09-06Thesisborn digital