Preparation of tantalum oxide aerogels by two-stepacid and basic catalyst method

Ta2O5 aerogels were prepared by sol-gel process and supercritical drying technique.The sol gel process mainly consisted of hydrolysis and condensation reaction was controlled by two-step catalyst.Ta2O5aerogels prepared with two-step acid and basic catalyst method show rigidity,translucence and low constriction in comparision with one-step acid catalyst method.The resulting aerogels were characterized by means of BET and SEM.It was found that Ta2 O5 aerogels have a higher inner surface of 493m2/g and more porous structure with two-step acid and basic catalyst method than one-step acid catalyst method.According to the non-local density functional theory(NLDFT),the pore width distribution was from 2to 8nm with two-step acid and basic catalyst method rather than from 2to 20nm with one-step acid catalyst method.SEM shows that a mount of nanoparticles randomly constructed consist of typical amorphous and mesoporous aerogels.The catalysis mechanisms of acid and basic for sol gel process are discussed initially.