Cerium-zirconium-based composite oxide, preparation method thereof and loaded automobile exhaust purification catalyst

Abstract

The invention discloses a cerium-zirconium-based composite oxide, a preparation method thereof and a supported automobile exhaust purification catalyst. The cerium-zirconium-based composite oxide is a pure cerium-zirconium composite oxide or a multi-element cerium-zirconium-based composite oxide containing an oxide of a doping element, and the cerium-zirconium-based composite oxide comprises 10-70% of cerium oxide, 20-70% of zirconium oxide and 0-10% of the oxide of the doping element; the crystal structure of the composite oxide contains a pyrochlore structure. The preparation method comprises the following steps: firstly, preparing an initial cerium-zirconium-based composite oxide with high thermal stability and high specific surface area, and then carrying out reduction treatment to obtain the cerium-zirconium-based composite oxide with high specific surface area and partial pyrochlore structure. The composite oxide prepared by the method can still keep high specific surface area and high oxygen storage/release performance even if being exposed to a relatively high temperature, the cerium-zirconium-based composite oxide with high specific surface area and the pyrochlore structure is obtained, and the problem that the high specific surface area and the pyrochlore structure are difficult to coexist is solved; catalytic activity of the automobile exhaust purification catalyst is further improved.

Description

Technical field[0001]The present invention belongs to the field of automobile exhaust gas purification catalysts, and more particularly to metal composite oxides, methods of producing the composite oxide and the application of the composite oxide in automobile exhaust gas purification catalysts.Background technique[0002]Harmful components in the motor vehicle exhaust gas mainly include hydrocarbon (HC), nitrogen oxidation (NOx), Carbon monoxide (CO) and particulate matter (PM), directly cause serious harm to human health and atmospheric environment. Further, the secondary pollution of motor vehicle exhaust gas has been confirmed is the main source of smog, its near ground ozone (O3) The contribution of the formation cannot be underestimated. Therefore, in order to protect the atmospheric environment to achieve ecological environment and social sustainable development, reduce motor vehicle exhaust pollution is imperative, which is also one of the important topics of my country's envi...

AI Technical Summary

Problems solved by technology

[0007] To sum up, it is difficult for the existing technology to achieve both high specific surface area and pyrochlore structure (high OSC) of cerium-zirconium-based composite oxides.

This also makes it difficult to make full use of the possible promotion effect of the interaction interface between the pyrochlore-containing cerium-zirconium-based composite oxide and the noble metal in the catalytic reaction, thus limiting the catalytic activity of the cerium-zirconium-based composite oxide under the pyrochlore structure. further improvement of

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