CATALYST FOR PURIFYING EXHAUST GAS

摘要

PURPOSE:To obtain a catalyst of high activity with little thermal deterioration and large specific surface area in which catalytic material is highly dispersed by providing a catalyst carrier layer of specified compsn. carrying a noble metal catalytic component on a ceramic formed body. CONSTITUTION:The catalyst is obtained by providing a catalyst carrier layer which carries a noble metal catalytic component on a ceramic formed body. This catalyst carrier layer is formed on the ceramic formed body from a silica sol containing aluminum nitrate as the starting material. Then at least one noble metal selected from platinum, palladium and rhodium is deposited thereon. By using gel-type silica sol containing aluminum nitrate as the starting material, fine silica particles (SiO2) are grown and a catalyst carrier layer having good stability at high temp. is obtd. Moreover, since the starting material is liquid, the catalyst carrier layer can be easily formed by dipping a ceramic formed body and then calcining.