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Type of Document Dissertation Author An, Hongmei Author's Email Address han@nd.edu URN etd-12072006-201140 Title Development of Novel Catalysts For Use in Diesel Particulate Filters Degree Doctor of Philosophy Department Chemical Engineering Advisory Committee
Advisor Name Title David Leighton Committee Chair Paul McGinn (advisor) Committee Co-Chair Albert Miller Committee Member Eduardo Wolf Committee Member Keywords
- Glass-based Catalysts
- Catalytic Soot Combustion
- Diesel Particulate Filters (DPF)
- Combinatorial Developement of Catalysts
- Potassium
- Diesel soot
Date of Defense 2006-11-03 Availability restricted Abstract DEVELOPMENT OF NOVEL CATALYSTS FOR USEIN DIESEL PARTICULATE FILTERS
Abstract
by
Hongmei An
Diesel particulate matter (PM) is part of a complex mixture that makes up diesel
exhaust, which has raised many health and environmental problems. Currently, the most
efficient technique to reduce PM emissions is Diesel Particulate Filter (DPF). However,
the collected particulates build up overtime and block the micropores of DPF, and
subsequently reduce the engine performance. This problem makes the regeneration of
DPF necessary. Among many possible regeneration techniques, catalytic regeneration is
the most applicable. The commercial catalysts used in most catalytic DPF are the costly
platinum based systems. The main aim of this dissertation is to develop novel,
economical catalysts for DPF applications.
Within this central theme, my work encompasses two major parts: (1)
combinatorial development of multiple-metallic oxides catalyst. Hundreds of single,
mixed and complex metal oxides were synthesized and studied based on a combinatorial
synthesis and characterization route. It was found alkali-doped metal oxides, especially
the ones containing potassium, showed higher activity than the other tested compositions.
Further investigation revealed that �active� potassium is the active species in these
Hongmei An
catalysts and sublimation of potassium during the soot combustion process resulted in the
fast degradation of the catalysts. These studies indicated the compounds that could timely
release �active� potassium might be promising economical and efficient catalysts for soot
combustion.
(2) Study of glass-based catalysts. To realize this timely release process, several
potassium-containing materials were examined. The potassium-glass was found to be
particularly promising. Potassium-glass catalysts showed better catalytic stability than
conventional potassium-catalysts and also possess resistance to common S, P and Zn
poisoning. Activity and stability tests performed in TGA and fixed bed flow reactor
indicated that the activity and degradation of glass catalysts are related to their
composition, particle size, glass/soot mixing method (contact), and ambient gas.
Moreover, some studies of microwave heating effects on diesel soot combustion
were performed. A novel microwave heated Thermogravimetric Analyzer was designed.
Measurements in microwave-TGA suggested that the apparent reduction in soot
combustion temperature with microwave heating might be not due to the enhancement of
microwave, but the result of the inability to measure the interior temperature of the
soot/catalyst mass.
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