Ce_1–xLa_xO_y solid solution prepared from mixed rare earth chloride for soot oxidation

韩雪¹，王亚飞²，郝红蕊¹，郭荣贵¹，胡运生¹，蒋文全¹

1. Institute of Rare Earth Metallurgical Materials General Research Institute for Nonferrous Metals2. School of Mechanical Engi- neering Beijing Institute of Petrochemical Technology

摘 要：Ce_1–xLa_xO_y solid solution was simply prepared using mixed rare earth chloride（RECl₃·x H₂O, RE=Ce, La>99%, containing unseparated Ce and La from rare earth metallurgical industry） as precursor by ultrasonic-assisted co-precipitation method with different ultrasonic frequencies（CLf, f=200, 400, 600, 800, 1000 Hz）. A compared Ce_1–xLa_xO_y solid solution（CL*） was also prepared by the same mothod with 10% less precipitant. X-ray diffraction results confirmed the formation of Ce1–xLaxOy solid solution, and the crystal structures of these catalysts were not very sensitive to ultrasonic frequency and precipitant amount. However, both of the factors had obvious effect on morphology and surface area of CL, and precipitant amount seem to play a more crucial role than ultrasonic frequency for Ce_1–xLa_xO_y solid solution preparation. When soot and catalyst were tight contacted, the peak temperature（Tpeak） of soot oxidation and oxygen reducing temperature for CLf catalysts decreased linearly with increasing surface area. Under loose contact condition, the Tpeak had obvious negative correlation with H₂ consumption. It was inferred that good reducibility of the Ce_1–xLa_xO_y solid solution favored the soot oxidation reaction. The Ce_1–xLa_xO_y solid solution prepared from unseparated rare earth chloride showed a good soot oxidaiton activity. Controlling the preparation conditions to prepare a CL catalyst would high surface area will enhance its reducibility and activity.

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