Project at a Glance
Project Status: complete
Title: Catalysts for automotive pollution control devices.
Principal Investigator / Author(s): Nobe, Ken
Contractor: School of Engineering and Applied Science, UCLA
Contract Number: 2-009-1A & 2-009-1
Research Program Area: Emissions Monitoring & Control
Topic Areas: Mobile Sources & Fuels
Over a hundred catalysts have been screened for potential use in automobile exhaust converters for removal of CO, hydrocarbons or NOx. The studies consisted of laboratory tests using dry gases as well as actual auto exhaust tests with the more promising catalysts. For CO and hydrocarbon oxidation only the noble metals showed sufficient activity to attain cold-start emissions standards. For reduction of NOx only ruthenium and mixed ruthenium oxide catalysts showed satisfactory low temperature activity and low production of undesired ammonia. Strontium yttrium ruthenium oxide shows considerable promise. Since warmup problems are not as severe for NOx control as for CO and hydrocarbon control, cheaper catalysts which have NOx-removal capability only at high temperatures may be tolerable; several base metal catalysts are promising for such operation. By using strontium yttrium ruthenium oxide catalyst in the first stage of a two-stage converter, over 90 percent NOx removal has been achieved. The fuel economy loss was about 11 percent. Extended testing of platinum catalyst in the second stage showed no appreciable deterioration for about 150 hours. Total removal of CO was observed up to that time. Degradation that occurred after that time was caused by a trace lead contamination of the unleaded gasoline supply.
For questions regarding research reports, contact: Heather Choi at (916) 322-3893
Stay involved, sign up with ARB's Research Email Listserver