| 摘要 |
A process of preparing metal oxide containing precious metals is provided to produce the metal oxide with excellent heat resistance useful for recirculating automobile exhaust gas by continuously reacting a mixture of precious metal compound, cerium based compound and lanthanum based compound except zirconium, scandium, yttrium and cerium based compounds. The process comprises continuous reaction of a reactive mixture which includes (i) water, (ii) water soluble precious metal compound, (iii) water soluble cerium compound and (iv) one selected from lanthanum compounds except Zr, Sc, Yt and Ce compounds at 200 to 700deg.C under pressure of 180 to 550 bars. The reactive mixture has metal molar ratio of precious metal to other metal except the precious metal ranging from 0.001 to 0.1. The water soluble precious metal compound is a compound of at least one selected from Pt, Pd, Rh, Ir, Ru and Ag. The cerium compound is selected from nitrate, sulfate, hydrochloric acid salt, oxalate or citrate.
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