| 摘要 |
A process for the preparation of monoliths of aerogels of metal oxides, which aerogel is either constituted by one single oxide, or is constituted by a mixture of oxides, is disclosed, which process consists of the following operating steps: (a) the relevant metal alkoxide(s) is/are mixed with water in the presence of a catalyst of acidic character; (b) the so obtained mixture is hydrolysed; (c) a colloidal suspension of the oxide of a metal equal to, or different from, the metal(s) used in the (a) step is added to the hydrolysate; (d) the so obtained colloidal solution is caused to turn into a gel (gelation) having the desired shape and dimensions; (e) the gel is washed; (f) the gel is dried at values of temperature and pressure which are higher than the critical pressure and temperature values of the solvent used for the washing. n |
