EXHAUST GAS CLEANING CATALYST AND EXHAUST GAS CLEANING METHOD

摘要

PROBLEM TO BE SOLVED: To provide an exhaust gas cleaning catalyst which exhibits a high NOxremoval activity even after exposure to a high-temperature atmosphere and is prevented from being poisoned by sulfur.

SOLUTION: The cleaning catalyst is one comprising a first catalyst powder prepared by allowing a porous oxide powder to carry at least Pt and an NOxocclusion material and a second catalyst powder prepared by allowing an oxide powder containing θ-alumina particles to carry at least Rh and an NOxocclusion material, wherein the first catalyst powder and the second catalyst powder are intermingled with each other. It does not happen that the Rh remains stabilized in an oxidation state because the Pt and the Rh are separately carried and because the θ-alumina scarcely undergoes a solid-phase reaction with the Rh because of its excellent heat resistance.

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