High-temperature automotive catalytic nitrogen oxide reduction over copper-lanthanum-alumina

Journal Article · Fri Aug 01 04:00:00 EDT 1997 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1002/chin.199745015· OSTI ID:532931

Ozawa, Masakuni; Suzuki, Suguru; Toda, Hajime ^[1]

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1. Nagoya Inst. of Tech., Tajimi, Gifu (Japan). Ceramics Research Lab.

The synthesis and nitrogen oxide (NO) removal activities of composite powders in the copper-lanthanum-alumina (Cu-La-Al{sub 2}O{sub 3}) system were studied, in regard to their high-temperature application as an automotive lean-burn exhaust catalyst. The solid-state reaction between the copper, the lanthanum, and the Al{sub 2}O{sub 3} support, at elevated temperature, was examined by X-ray diffractometry and electron-spin resonance. Lanthanum impregnation into the Al{sub 2}O{sub 3} support successfully helped to form active composite powders that could remove nitrogen oxides and consisted of {gamma}-Al{sub 2}O{sub 3} and LaAlO{sub 3}, after heat treatment at 900 C, and mainly CuLaAl{sub 11}O{sub 19} at 1,000 C. Cu{sup 2+} cations were observed to be isolated in the present powders, even after heat treatment up to 1,000 C. The evaluation of NO removal activity over lanthanum-modified copper-Al{sub 2}O{sub 3} catalysts that were subjected to harsh heat treatment was performed using a model exhaust-gas mixture of NO, carbon monoxide (CO), propene (C{sub 3}H{sub 6}), carbon dioxide (CO{sub 2}), water vapor (H{sub 2}O), and an excess of oxygen (O{sub 2}). The catalyst that was composed of 20 mol% copper, 10 mol% lanthanum, and Al{sub 2}O{sub 3} and heat treated at 900 and 1,000 C in air showed NO removal conversion efficiencies of 14% and 8%, respectively, under the lean-burn conditions of an air:fuel (A/F) ratio of 18 and a space velocity (SV) of 100,000 h{sup {minus}1}. Lanthanum-modified copper-Al{sub 2}O{sub 3} powders are potentially useful as a NO removal catalyst, when applied to an automotive lean-burn exhaust.

• Sponsoring Organization: USDOE
• OSTI ID: 532931
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 8 Vol. 80; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
ALUMINIUM OXIDES
CATALYTIC CONVERTERS
CHEMICAL COMPOSITION
COMPOSITE MATERIALS
COPPER
EFFICIENCY
LANTHANUM
NITROUS OXIDE
POWDERS
REDUCTION
SYNTHESIS