EXHAUST GAS CLEANING CATALYST

摘要

PROBLEM TO BE SOLVED: To maintain the highly dispersed and supported state of a catalytic metal even after an endurance test at a high temperature as well as to further enhance the heat resistance of a carrier. SOLUTION: The objective exhaust gas cleaning catalyst comprises a carrier comprising hollow powder of the multiple oxide of Al2O3 and the oxide of a rare earth element capable of forming solid solution with Al2O3 and a metal or metal oxide having catalytic activity supported on the carrier. The amount of the rare earth element in the carrier is 1-8 mol% as the atomic ratio to Al. Since γ-phase is stabilized by the addition of the rare earth element, the reduction of the specific surface area of the carrier at high temperature can be suppressed. Since the powder is hollow, gas diffusibility is enhanced owing to the increased pore volume, the reduction of the specific surface area is suppressed and the catalytic metal is inhibited from entering into solid solution.