Research for High Concentration of Precious Metal and Thin Layer of Catalyst Top Layer

Accession number;05A0846846
Title;Research for High Concentration of Precious Metal and Thin Layer of Catalyst Top Layer
Author; INOSE SHOJI (Honda R & D Co., Ltd.) OKAYAMA TATSUYA (Honda R & D Co., Ltd.)
Journal Title;Honda R&D Tech Rev
Journal Code:L0353A
ISSN:0915-3918
VOL.17;NO.2;PAGE.129-135(2005)
Figure&Table&Reference;FIG.11, REF.11
Pub. Country;Japan
Language;Japanese
Abstract;Reduction of the precious metal loading of a catalyst generally causes a decline in light-off performance. Study of the low temperature reaction mechanism of catalysts indicated the importance of the top layer in the reaction, thus increasing reactivity in the top layer was established as an objective. The concentration of precious metals in the top layer was increased, and the thickness of the layers was reduced. At the same time, the precious metal loading of the subjacent layer, which contributes little to light-off performance, was reduced by 80%. However, increasing the concentration of precious metals in the top layer caused a reduction in performance due to a sintering effect between the metals. Research was therefore conducted on the employment of a high-thermostability support material (alumina) to control the sintering. This research has enabled the development of a three-way catalyst with significantly reduced precious metal loading while retaining conversion performance equivalent to that of conventional catalysts. (author abst.)