Question

Answer the following

Describe the sol-gel method of preparation for nanoparticles.

Answer 1

 Sol-gel process:

a. The sol-gel process is an example of wet chemical synthesis of nanomaterials.

b. This technique is based on inorganic polymerization reactions.

c. It is generally carried out at room temperature and includes four steps: Hydrolysis, polycondensation, drying, and thermal decomposition.

d. This method is widely employed to prepare oxide materials.

e. Schematic representation:

Schematic representation of the sol-gel process of synthesis of nanoparticles

f. The reactions and steps involved in the sol-gel process can be described as follows:

\[\ce{\underset{\text{(Metal alkoxide)}}{MOR} + H2O -> MOH + ROH}\] (Hydrolysis)

\[\ce{MOH + ROM -> M-O-M + ROH}\] (Condensation)

1. Formation of the different stable solution of the alkoxide or solvated metal precursor.

2. Gelation resulting from the formation of an oxide or alcohol bridged network (gel) by a polycondensation reaction.

3. Aging of the gel means during that period gel transforms into a solid mass.

4. Drying of the gel: In this step, water and other volatile liquids are removed from the gel network.

5. Dehydration: The material is heated at temperatures up to 800°C.