NOx REMOVAL CATALYST AND NOx REMOVAL SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide an NOx removal catalyst which eliminates sulfur poisoning of catalytic metals even in operation in a stoichiometric to rich region and can efficiently remove NOx and to provide an NOx removal system. SOLUTION: The NOx removal catalyst used in cleaning of exhaust gas in a lean region or in a stoichiometric to rich region contains catalytic metals and an oxygen absorbing and discharging material and the catalytic metals carried on the oxygen absorbing and discharging material adsorb SOx in exhaust gas as sulfate or sulfite. The catalytic noble metals include platinum and 5-50% platinum is supported on ceria and adsorbs SOx as sulfate or sulfite.