EXHAUST PURIFYING CATALYST

摘要

PROBLEM TO BE SOLVED: To provide a catalyst whose deterioration caused by phosphorus poisoning thereof is inhibited.SOLUTION: An exhaust purifying catalyst for purifying exhaust including phosphorus comprises catalyst layers 2 and 3 laminated on a carrier 1, and a layer 4 including the unsaturated phosphates being the precursors of compounds to become phosphates by combining with phosphorus included in exhaust. Phosphorus in the exhaust reacts preferentially with the unsaturated phosphates by the presence of the unsaturated phosphate-containing layer 4 to gradually form the saturated phosphates. Thereby, poisoning of noble metals and oxides in the catalyst layer is suppressed.