PRODUCTION OF CATALYST FOR PURIFYING EXHAUST GAS

摘要

PURPOSE:To improve high-temp. durability of the title catalyst by allowing a carrier coated with activated alumina to be impregnated with a mixed aq. soln. of both dinitrodiamineplatinum and rhodium nitrate or ammonium hexanitrorhodate. CONSTITUTION:A carrier coated with activated alumina is impregnated with a mixed aq. soln. of both dinitrodiamineplatinum and rhodium nitrate or ammonium hexanitrorhodate and dried and thereby a catalyst carrying platinum and rhodium for purifying exhaust gas is produced. The concn. of the mixed soln. for carrying it is regulated to 0.05-5g/l as total of platinum and rhodium preferably to 0.5-3g/l. When applying the above method, degree of solid solution of platinum and rhodium is enhanced and heat resistance of noble metal is improved and thereby high-temp. durability of the catalyst for purifying exhaust gas is improved.