CATALYST FOR PURIFYING EXHAUST GAS AND DEVICE AND SYSTEM THEREFOR USING THE SAME

摘要

PROBLEM TO BE SOLVED: To produce a catalyst for purifying exhaust gas excellent in resistance to poisoning and having long life by depositing a catalytic active component by depositing a carrier layer made of a porous inorg. matter on a waste gas purifying surface of a heat resistant honeycomb structure and forming an oxide film thereon. SOLUTION: A carrier layer consisting of the porous inorg. matter 2 having fine hole and high specific surface area such as magnesia and γ-alumina is deposited on the exhaust gas purifying surface of the heat resistant honeycomb structure such as cordierite and mullite. An oxide film 3 consisting of an oxide of silicon and/or titanium is formed on an upper surface of the carrier layer. This oxide film 3 prevents an adsorption and/or reaction of a sulfur oxide in the waste gas and the porous inorg. matter 2. Moreover, an active catalytic component 4 such as noble metal, base metal and metal oxide is deposited on the upper surface of the oxide film 3. The catalyst for purifying exhaust gas obtained by this method prevents a poisoning of the carrier and the active catalytic component due to the sulfur oxide in the exhaust gas and purifies the exhaust gas over a long period of time in high purifying ratio.