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US 7,851,405 B2Granted
Exhaust gas purifying catalyst and manufacturing method thereof
AssigneesNissan Motor Co., Ltd., RENAULT s.a.s.
InventorsHironori Wakamatsu, Maki Shimada, Masanori Nakamura, Katsuo Suga, Hiroto Kikuchi, Tetsuro Naito, Toshiharu Miyamura, Jun Ikezawa
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Abstract
An exhaust gas purifying catalyst that includes noble metal particles, first compounds which support the noble metal particles and suppress movement of the noble metal particles, and second compounds which encapsulate the noble metal particles and the first compounds. The second compounds suppress the movement of the noble metal particles and suppress coagulation of the first compounds following mutual contact of the first compounds.
Claims21
An exhaust gas purifying catalyst, comprising:
- noble metal particles;
- first compounds contacting and chemically bonding the noble metal particles to suppress movement of the noble metal particles, the first compounds being a composite oxide containing a rare earth element;
- and
- second compounds on peripheries of the first compounds on which the noble metal particles are supported, wherein the second compounds contain γ-alumina derived from boehmite,
- wherein a single piece or aggregate of the first compounds which supports a noble metal particle is fixed in a section partitioned from other pieces or aggregates of first compounds by the second compounds, thereby suppressing movement of the noble metal particle and suppressing coagulation of first compounds with each other, and
- wherein D2/D3 as a ratio of a secondary particle diameter (D2) of the first compounds with respect to an average pore diameter (D3) of pores of the second compounds is 1 or more.
3 more elements
Dependencies are inferred from the claim text.