Question

Name three methods for nanomaterial synthesis. Briefly explain each method. You may use sketches to illustrate your answers.

Answer 1

1)Hydrothermal synthesis is typically carried out in a pressurised

vessel called an autoclave with the reaction in aqueous solution.

The temperature in the autoclave can be raised above the boiling

point of water, reaching the pressure of vapour saturation.

Hydrothermal synthesis is widely used for the preparation of TiO2

nanoparticles which can easily be obtained through hydrothermal

treatment of peptised precipitates of a titanium precursor with water

2)

The Solvothermal method is identical to the hydrothermal method

except that a variety of solvents other than water can be used for

this process. This method has been found to be a versatile route for

the synthesis of a wide variety of nanoparticles with narrow size

distributions, particularly when organic solvents with high boiling

points are chosen.

  

3) Chemical Vapor Deposition (CVD)

This process is often used in the semiconductor industry to

produce high-purity, high-performance thin films. In a typical CVD

process, the substrate is exposed to volatile precursors, which react

and/or decompose on the substrate surface to produce the desired

film. Frequently, volatile by products that are produced are

removed by gas flow through the reaction chamber. The quality of

the deposited materials strongly depends on the reaction

temperature, the reaction rate, and the concentration of the

precursor