Sol-gel preparation of AlPO4-SiO2 glasses with high surface mesoporous structure

Transparent and colorless amorphous silica-aluminum phosphate gels and glasses along the composition line, xAlPO(4)-(1-x) SiO2 were prepared via the sol-gel route using tetraethylorthosilicate (TEOS), aluminum lactate, and ammonium dihydrogen phosphate as precursors. The glass-forming range was significantly extended, compared with that accessible by previously reported routes. After calcination at 600 degrees C, the amorphous AlPO4-SiO2 material exhibits an attractive mesoporous structure with surface areas as high as 582 m(2) g(-1). With increasing gel-processing and conversion temperature, the average degree of P/Al connectivity increases, while the Q(3) silicon units present in the gels are gradually converted to Q(4) units. After sample calcination above 600 degrees C for 8 h, the NMR results indicate that the structure of the prepared materials is composed of AlPO4- and SiO2-nanodomains.