The sol-gel process typically involves three main stages:
1. Hydrolysis: In this stage, metal alkoxides react with water to form hydroxyl groups. 2. Condensation: The hydroxyl groups undergo condensation reactions to produce a three-dimensional metal-oxygen-metal (M-O-M) network. 3. Aging and Drying: The gel is aged to strengthen the network and then dried to remove the remaining liquid phase, resulting in a xerogel or aerogel.
