CERAMIC CARRIER AND CERAMIC CATALYST

• Main Authors: ANDO YOSHIYASU, NAKANISHI TOMOHIKO, YAMADA MASANORI
• Format: Patent
• Language: English
• Published: 26.02.2002
• Edition: 7
• Subjects: BLASTING; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; 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; LIGHTING; MACHINES OR ENGINES IN GENERAL; MECHANICAL ENGINEERING; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; SEPARATION; STEAM ENGINES; THEIR RELEVANT APPARATUS; TRANSPORTING; WEAPONS

PROBLEM TO BE SOLVED: To obtain a ceramic carrier used in a catalyst for cleaning NOx of a lean burn engine, low in cost, excellent in high temperature durability and capable of keeping catalytic activity over a long period of time, and to produce a ceramic catalyst. SOLUTION: The ceramic carrier to be used is constituted by forming a diffusion preventing layer, which prevents the diffusion of an alkali metal, an alkaline earth metal, or the like, supported as an NOx occluding material, on the surface of a cordierite honeycomb structure. The diffusion preventing layer comprises a ceramic material such as Y2O3, NiO, CeO2, or the like, with a melting point of >1,000 deg.C, not reacting with the alkali metal, the alkaline earth metal, or the like, at temperature up to 1,000 deg.C, and, since the internal diffusion of a catalytic component such as potassium, or the like, and the reaction thereof with cordierite are prevented by the diffusion preventing layer, catalytic capacity is not lowered and durability is largely enhanced.