Method for preparing large-specific-surface-area rare earth oxides or composite oxides through spray pyrolysis

Abstract

The invention provides a method for preparing large-specific-surface-area rare earth oxides or composite oxides through spray pyrolysis. The method includes dissolving rare-earth chlorides, or the rare-earth chlorides and metal chlorides, in water to obtain a solution, and adding carboxylic acid for evenly stirring; spraying the mixed solution into a calcinator for calcination by taking the air as a carrier gas at the temperature of 400-1700 DEG C and keeping particles in a pyrolyzing furnace for 0.5-2.5 seconds to obtain carbon loaded rare earth oxide precursors; calcinating the precursors at the temperature of 500-1000 DEG C for 1-10 hours to obtain the rare earth oxides or composite oxides with the specific surface area of 26-83m<2>.g<-1>. The method has the advantages that the rare-earth chlorides, or the rare-earth chlorides and the metal chlorides, serve as raw materials, the carboxylic acid is added, the carbon loaded rare earth oxide precursors in a micro crystalline state or in a micro-crystalline and amorphous mixed solid solution state are obtained through spray pyrolysis, and further, the large-specific-surface-area rare earth oxides or composite oxides are calcinated.

Description

technical field [0001] The invention belongs to the technical field of materials, in particular to a method for preparing rare earth oxides or composite oxides with large specific surface area by spray pyrolysis. Background technique [0002] In recent years, rare earth oxides or composite oxides have been widely used in the fields of catalysts, functional ceramics, oxygen ion conductors, and solid fuel cells. Experiments have confirmed that rare earth oxides or composite oxides have unique crystal structures, electromagnetic properties, and high oxidation and reduction catalytic activities. Their preparation methods and applications have become a hot topic in the fields of catalytic materials, functional materials, etc. Preparation methods of rare earth oxides or composite oxides with physical and chemical properties, such as preparation of rare earth oxides and rare earth composite powders with different particle sizes and specific surface areas. [0003] At present, the ...

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Problems solved by technology

After decades of development, the spray pyrolysis method has become an important micropowder preparation process. At present, there are many patents (CN201010534886.X, CN201010534886.X, CN201210081225.5, CN201210190297.3, CN201410741766, CN201510311060) reported using this method The method can prepare rare earth oxides or composite oxides with small particle size, narrow size distribution, purity greater than 99%, and uniform composition distribution, but for the preparation of specific surface area exceeding 80m 2 .g -1 However, there are few reports on rare earth oxides or composite oxides. Such rare earth oxides or composite oxides with large specific surface area have important applications in the preparation of three-way catalysts (TWCs) for automobile exhaust purification, which can improve the oxygen storage capacity of catalysts. The role of capacity, catalyst activity and stability

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