Novel synthesis of high surface area MgAl2O4 spinel as catalyst support

A modified sol-gel route, by combining gelation and coprecipitation processes, was developed for the synthesis of high surface area MgAl2O4 spinel precursors. The obtained precursors were then calcined in flowing air at temperatures ranging from 500 to 900 degreesC. The formation of new phases upon calcinations was investigated using X-ray diffraction, thermal gravimetric analysis, and Fourier transform infrared spectroscopy (FTIR). Single-phase spinel powder with uniform pore size distribution was formed at temperatures as low as 600 degreesC. it was found that the thermal stability of the as-synthesized spinels is higher than that reported by other preparation methods. After calcinations at 800 and 950 degreesC for 8 h, the specific surface area reaches a level of 182 and 136 m(2.)g(-1), respectively. And the degree of crystallinity is higher than other preparation methods as illustrated by samples calcined at 800 degreesC. The amount ofPVA added significantly affects the surface area of the samples. With increasing the ratio of M/PVA, the surface area of the resulting spinels increased accordingly. (C) 2004 Elsevier B.V. All rights reserved.