Nissan Motor Company Limited

Yoshiaki Hiramoto

Shinji Yamamoto

Masahiro Takaya

Haruhiko Shibayama

Katsuo Suga

Yasunari Hanaki

Kazuyuki Shiratori

Hitoshi Onodera

Fumihiro Uchikawa

Keita Manyu

Masanori Nakamura

Hiroshi Morita

Hiroshi Akama

Hironori Wakamatsu

Tetsuro Naito

Hiroaki Kaneko

Hiroto Kikuchi

Toru Nishizawa

Hiroyuki Kanesaka

Hideaki Morisaka

Naito Tetsuro

An exhaust gas purifying catalyst comprises: a plurality of catalyst units which contain anchor particles that support noble metal particles; and an enclosure material that internally contains the plurality of catalyst units and separates the catalyst units from each other. Both the anchor particles and the enclosure material contain an alkali element and/or an alkaline earth element. Due to this configuration, this exhaust gas purifying catalyst is capable of maintaining the exhaust gas purification performance by suppressing agglomeration of the noble metal particles even in cases where the ambient temperature is high.

Exhaust gas purifying catalyst and method for producing same

An exhaust gas purifying catalyst is constituted by: noble metal particles (); first compounds () which support the noble metal particles (); second compounds () different in type from the first compounds (); and oxides () which surround the noble metal particles (), the first compounds () and the second compounds (). A median diameter of the first compounds () and a median diameter of the second compounds () satisfy a relationship of a following inequality:median diameter of first compounds&#x3c;median diameter of second compounds.

Exhaust gas purifying catalyst

In the present invention, slurry is formed by mixing noble metal-supported powder particles () and a binder () with each other in a liquid (Step S), and the noble metal-supported powder particles () are dispersed by applying vibrations to the slurry (Step S), and thereafter, the slurry is spray dried while keeping a state where the noble metal-supported powder particles () are dispersed (Step S), whereby noble metal-supported powder () is produced. In the noble metal-supported powder () produced by such a method, pores through which exhaust gas flows are formed appropriately, and accordingly, exhaust gas purification performance can be enhanced.

Method of producing noble metal-supported powder, noble metal-supported powder and exhaust gas purifying catalyst

An exhaust gas purifying catalyst () includes: a three-dimensional structural substrate () having a plurality of cells () partitioned by cell walls () having pores (); and catalyst layers () formed in the three-dimensional structural substrate (). The catalyst layers () have pore-cover portions () formed on surfaces () of the pores () of the cell walls (). In addition, the catalyst layers () of the pore-cover portions () have activated pores () with a pore diameter of 0.1 micrometers to 10 micrometers. In the exhaust gas purifying catalyst (), the obstruction of the vent holes (pores ()) in the catalyst layers () can be controlled, and the pressure loss can be reduced.

Exhaust gas purifying catalyst and manufacturing method of the same

An exhaust gas purifying catalyst includes a honeycomb substrate, and HC adsorbent layers containing zeolite and having a thickness ranging from 100 &#x3bc;m to 500 &#x3bc;m. Each of the HC adsorbent layers has an approximately circular surface on a cross section perpendicular to a direction where each of the cells of the honeycomb substrate is extended, and has circumferential-direction cracks extended in a circumferential direction and radial-direction cracks extended in a radial direction. The circumferential-direction cracks and the radical-direction cracks are unconnected to each other or are connected in an extent not to cause layer exfoliation in the HC adsorbent layers. A manufacturing method of the exhaust gas purifying catalyst is to coat slurry containing zeolite on the honeycomb substrate plural times, to dry or fire the coated slurry, and to form the HC adsorbent layers.

An exhaust gas purifying catalyst including a carrier having a plurality of cells as exhaust gas passages, an HC adsorbent layer formed on the carrier of each of the cells, and an upper catalyst layer disposed on an upstream side of each of the exhaust gas passages on the HC adsorbent layer and a lower catalyst layer disposed on a downstream side of each of the exhaust gas passages on the HC adsorbent layer. The upper catalyst layer includes more O2-storage material than the lower catalyst layer, and the lower catalyst layer includes a catalyst having a wider activation range than the upper catalyst layer.

Exhaust gas purifying system

Growing community of inventors

Yokosuka, Japan

Yoshiaki Hiramoto