A template-free synthesis of mesoporous crystalline γ-alumina through partial hydrolysis of aluminum nitrate aqueous solution

Abstract

The synthesis of mesoporous alumina with large surface area and crystalline nature is still a great challenge because of the susceptibility to hydrolysis of aluminum precursors. Here, we first report a preparation of NH4NO3 and Al species hybrids containing Keggin-Al13 [Al13O4(OH)24(H2O)127+] through a simple condensation of Al(NO3)3 aqueous solution partially hydrolyzed with (NH4)2CO3. Thermal treatment at a low temperature of 200°C could successfully transform the hybrid to γ-alumina, which exhibited a wormhole-like mesoporous structure with high surface area of 380–450m2/g and narrow PSD after completely removing NH4NO3 at 300°C.