Purification catalyst for exhaust gas, production method therefor, and purification catalyst device for exhaust gas

Abstract

A purification catalyst for exhaust gas enhances the activities of noble metals, preventing a drop in activities at high temperatures, and exhibiting a satisfactory performance even in low temperature (below 400° C.) operation when starting up or during idling of automobiles. The Pd-based composite oxide contains at least one element selected from alkaline earth metals.

Description

technical field [0001] The present invention relates to an exhaust gas purification catalyst and a manufacturing method thereof, and a vehicle exhaust gas purification catalyst device, in particular to a manufacturing technology of an exhaust gas purification catalyst, which can make the nitrogen oxides in the gas discharged from internal combustion engines such as automobiles run at low temperature (NO x ), hydrocarbons (HC) and carbon monoxide (CO) are effectively purified and reduced at the same time. Background technique [0002] In the exhaust (such as CO, HC, NO, NO 2 etc.), noble metal elements (Pt, Rh, Pd, Ir) are known to have excellent properties, and therefore, the above-mentioned noble metals are particularly suitable for use in exhaust gas purification catalysts. Usually these noble metals are mixed with additives such as lanthanum (La), cerium (Ce), neodymium (Nd) or loaded on the carrier Al with a high specific surface area. 2 o 3 use on. On the other han...

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Problems solved by technology

However, loaded on Al 2 o 3 Even if the Pd on the surface exists in the state of PdO in the initial stage, it will be reduced to Pd in ​​the metal state at high temperature (greater than or equal to 900 ° C), and the Pd aggregation will cause the reduction of active sites and greatly reduce the activity.

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