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

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 .g . 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.