Method of preparing metal oxide-silica composite aerogel and metal oxide-silica composite aerogel prepared by the same
Provided are a method of preparing a metal oxide-silica composite aerogel, and a metal oxide-silica composite aerogel having an excellent weight reduction property prepared by the method. The method includes a step of adding an acid catalyst to a first water glass solution to prepare an acidic water glass solution (step 1); a step of adding a metal ion solution to the acidic water glass solution to prepare a precursor solution (step 2); and a step of adding a second water glass solution to the precursor solution and performing a gelation reaction (step 3) to yield a metal oxide-silica composite wet gel, wherein, in steps 2 and 3, bubbling of an inert gas is performed during the adding of the metal ion solution or the second water glass solution, respectively.
1. A method of preparing a metal oxide-silica composite aerogel, the method comprising:
1) adding an acid catalyst to a first water glass solution to prepare an acidic water glass solution;
2) adding a metal ion solution to the acidic water glass solution while bubbling an inert gas into the acidic water glass solution to prepare a precursor solution having a reduced amount of dissolved oxygen; and
3) adding a second water glass solution to the precursor solution and performing a gelation reaction to yield a metal oxide-silica composite wet gel,
wherein, in step 3), bubbling of an inert gas is performed during the adding of the second water glass solution.
2. The method according to claim 1 , wherein the inert gas comprises one or more of helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), nitrogen (N 2 ), and carbon dioxide (CO 2 ) gases.
3. The method according to claim 1 , wherein the pH of the acidic water glass solution is 0.1 to 2.9.
4. The method according to claim 1 , wherein the concentration of the first water glass solution is 0.01 M to 2.0 M.
5. The method according to claim 1 , wherein the concentration of the metal ion solution is 0.01 M to 2.0 M.
6. The method according to claim 1 , wherein the concentration of the second water glass solution is 0.5 M to 6.0 M.
7. The method according to claim 1 , wherein the concentration of the second water glass solution is higher than the concentration of the first water glass solution.
8. The method according to claim 1 , wherein the second water glass solution is added such that the pH of the precursor solution becomes 3 to 10.
9. The method according to claim 1 , wherein the metal ion solution comprises one or more metal ions selected from the group consisting of alkali metals, alkaline earth metals, lanthanides, actinides, transition metals, and metals in Group 13 (IIIA).
10. The method according to claim 1 , wherein the metal ion solution is a binary metal ion solution comprising calcium ions (Ca 2+ ) and magnesium ions (Mg 2+ ).
11. The method according to claim 10 , wherein a molar ratio of the calcium ions (Ca 2+ ) to the magnesium ions (Mg 2+ ) in the metal ion solution is 1:1 to 1:20.
12. The method according to claim 1 , wherein the acid catalyst is one or more than one acid selected from the group consisting of hydrochloric acid, nitric acid, acetic acid, sulfuric acid, and hydrofluoric acid.
13. The method according to claim 1 , further comprising, after step 3, washing and drying the metal oxide-silica composite wet gel.