Cerium iron zirconium solid solution oxide catalyst and its preparation and application

Abstract

The invention relates to a solid solution oxide catalyst, in particular to a cerium oxide catalyst doped with iron and zirconium. The chemical composition and weight content are: 5-98 parts of cerium, 1-90 parts of iron and 1-90 parts of zirconium. The invention also provides its preparation method, which breaks through the limitation that the traditional preparation method cannot do more than 50% of various other metals in the ceria lattice, and can dope iron and zirconium into cerium oxide in a wide range of ratios In the crystal lattice, a solid solution oxide with uniform crystal phase is formed, which increases the lattice distortion of cerium oxide and increases the oxygen storage capacity of the oxide. The cerium-iron-zirconium solid solution oxide involved in the present invention has extremely high low-temperature NOx reduction activity as a catalyst; it does not need to support noble metals, and its low-temperature reduction NOx activity can exceed that of cerium-zirconium solid solution catalysts loaded with noble metals; in the presence of oxygen, The NOx reduction activity is equivalent to that of supported noble metal catalysts, which can reduce or replace the use of noble metals.

Description

technical field [0001] The invention relates to a cerium-iron-zirconium solid solution oxide nanomaterial, in particular to a cerium-iron-zirconium solid solution oxide catalyst with a high oxygen storage capacity and a wide doping ratio. The catalyst has high low-temperature activity and does not need to support noble metals. That is, it can reduce NOx and oxidize CO at low temperature, and its activity can exceed that of the cerium-zirconium solid solution catalyst loaded with noble metals, thereby reducing or replacing the use of noble metals. Background technique [0002] Nitrate is one of the key factors for the explosive growth of PM2.5, and reducing NOx from coal combustion and motor vehicle emissions is the top priority. Pollutant emissions are high during cold start of automobiles, accounting for more than 50% of all pollutant emissions, so it is necessary to develop low-temperature and high-activity NOx reduction catalysts. The common problems of existing cerium-z...

AI Technical Summary

Problems solved by technology

The common problems of existing cerium-zirconium solid solution catalysts are: low low temperature activity, high light-off temperature, insufficient oxygen storage and release capacity of oxides, and narrow air-fuel ratio window

At present, there are many modification methods for cerium oxide catalysts, most of which are to improve the oxygen storage capacity of cerium oxide by doping other metals, but the common problem is that the content of doped metals is low, such as too much doped metals , it is difficult to completely dope the metal into the lattice of cerium oxide, and the doped metal will exist in the form of a separate oxide, which cannot form a uniform solid solution structure, thus failing to enhance the oxygen storage capacity

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