Research on preparation of flowerlike cerium oxide by using polyvinyl alcohol assisted with ethylene glycol

Cerium oxide with irregular shapes provided by a company was dissolved by adding concentrated nitric acid and hydrogen peroxide. With deionized water or both deionized water and ethylene glycol as solvent, polyvinyl alcohol as a dispersant, and ammonium oxalate as a precipitant, cerium oxalate precursors can be synthesized by direct precipitation method. Then, in a high-temperature reactor, the cerium oxalate precursors were calcinated at 600 ℃ for 2 h, heating rate of 8 oC/min. After that, cerium oxide was obtained. With deionized water as solvent and polyvinyl alcohol as a dispersant, results showed that the obtained cerium oxide was fragile and that its sizes varied. Besides, the thickness, length and width of the cerium oxide was about 100 nm, 3~10 μm, and 1~2 μm, respectively. And its specific surface area was 14.9 m²/g. When both deionized water and ethylene glycol were used as solvent and polyvinyl alcohol was used as dispersant, the prepared cerium oxide was evenly shaped and had a smooth surface. The length, width and thickness of the cerium oxide were about 4 μm, 1.5 μm and 100 nm, respectively. The flowerlike cerium oxide with an average diameter of 2~5 μm had a specific surface area of 21.45 m²/g. Based on the experiment result, it could be expected that other flowerlike rare earth oxides could be regulated by using polyvinyl alcohol assisted with ethylene glycol.