Synthesis of nanostructure mixed oxides CeO2-Al2O3 by the gel combustion method

Abstract

The nanostructure mixed oxides powder CeO₂–Al₂O₃ has been synthesized by the combustion of gel from polyvinyl alcohol (PVA) as polymer basic and mixture metal nitrate at 850^oC for 2 hours. Characterization of mixed oxides powder CeO₂–Al₂O₃ was determined by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and specific surface area analysis from N₂ adsorption data at 77 K by Brunaure Emmet Teller (BET) method. The gel combustion method was a successful method with short time for synthesis, available raw materials and without special equipment. The simple phase of mixed oxides powder CeO₂–Al₂O₃ were obtained from thermal treatment at 850^oC for 2 hrs. The optimum conditions of synthesis method: (Al³⁺+Ce⁴⁺)/PVA molar ratio = 1:3, Ce⁴⁺/Al³⁺ molar ratio = 5/5, pH = 4, gel formation temperature at 80^oC. Samples synthesized under optimal conditions has average crystalline size <  50 nm with large specific area of about 87.5 m²/g. The effects to structure, property of mixed oxides powder CeO₂-Al₂O₃ as calcining temperature, gel formation pH and Ce⁴⁺/Al³⁺ molar ratio have been studied.