Ceria-zirconia-based composite oxide oxygen storage material, exhaust gas cleaning catalyst, and honeycomb structure for exhaust gas cleaning

• Main Authors: Itoh, Tomoharu, Hidaka, Yusuke, Okamoto, Kenji, Uede, Hiroki, Yamaba, Masasuke
• Format: Patent
• Language: English
• Published: 27.04.2021
• Subjects: BLASTING; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSESC01D OR C01F; ENGINE PLANTS IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNALCOMBUSTION ENGINES; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES ORENGINES IN GENERAL; HEATING; INORGANIC CHEMISTRY; LIGHTING; MACHINES OR ENGINES IN GENERAL; MECHANICAL ENGINEERING; METALLURGY; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; SEPARATION; STEAM ENGINES; THEIR RELEVANT APPARATUS; TRANSPORTING; WEAPONS

A ceria-zirconia-based composite oxide oxygen storage material with a fast oxygen storage rate having an OSC ability enabling fast response to changes in exhaust gas which does not greatly fluctuate in composition, but varies at a fast rate near the stoichiometric air-fuel ratio, an exhaust gas purification catalyst, and a honeycomb structure for exhaust gas purification are provided. A ceria-zirconia-based composite oxide oxygen storage material, which oxygen storage material has a molar ratio of cerium and zirconium, by cerium/(cerium+zirconium), of 0.33 to 0.90, has an ion conductivity measured by an AC impedance method of 1×10−5S/cm or more at 400° C., and contains metal ions M of one or more types of rare earth elements selected from Sm3+, Eu3+, Pr3+, Gd3+, and Dy3+ with a coordination number of over 7.0 in an amount of 0.5 mol % to 15 mol % with respect to the total amount of cations.