Phase transition of SBA-1 induced by embedded heteropoly acids

摘要

Molybdenum incorporated SBA-1 was synthesized under acidic conditions using hexaammonium heptamolybdate (NH_4)_6Mo_7O_(24) · 6H_2O, phosphomolybdic acid (H_3PMo_(12)O_(40)), and silicomolybdic acid (H_4SiMo_(12)O_(40)) as Mo precursors. Treatment of as-synthesized Mo-SBA-1 obtained from H_4SiMo_(12)O_(40) in 1-octanol resulted in the phase transition from Pm3n cubic to a lamellar structure. The AHM- and H_3PM_(12)O_(40)-derived materials gave mixtures of these two phases while complete phase transition occurred for the H_4SiMo_(12)O_(40) -derived one.