Facile synthesis of highly thermal-stable doped alumina with high surface area by low temperature solid-state reaction

Abstract

Alumina and M-(La, Ba, Si) doped alumina were prepared by a facile low temperature solid-state reaction route and using cheap inorganic raw materials without any surfactants, in which only a harmless byproduct to environment was NH4Cl. The results show that all the prepared samples have a mesoporous structure and the BET surface area of as-synthesized alumina precursor has reached 326m2/g. Si-doped alumina exhibits remarkable thermal stability and high surface area (135–163m2/g) and the Ba-doped alumina have a large pore volume (0.44–0.95cm3/g) even after calcination at 1100°C for 10h. The nature of dopants and their concentrations have a significant influence on the textural properties and morphologies of M-alumina. The precursor synthesized can be converted to lower crystal ammonium aluminum carbonate hydroxide (AACH) by further thermal treatment. Si-doped alumina prepared by alumina from thermal decomposition of AACH possessed the superior thermal stability, and the surface area of 25%Si-Al2O3 calcined at 1100°C for 10h can reach 176m2/g. This facile synthetic route of alumina is an environmental friendly and convenient, and can be used in synthesis of other metal oxide porous materials.