Environmental Engineering Reference
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h is method is useful for preparation of nanocomposites and
nanograined bulk material.
12.11.2 Bottom-up approach
h is approach is solely based upon chemical principles, it involves:
• Pyrolysis
• Inert gas condensation
• Solvothermal reaction
• Sol-gel fabrication
• Structured media
Bottom-up Synthesis
I.
Gas Phase Synthesis
• Pyrolysis
• Inert gas condensation
II.
Liquid Phase Synthesis
• Solvothermal process
• Sol-gel process
• Micellar structure media
III.
Vapor Phase Synthesis
Nanoparticles of wide range can be prepared by a variety
of methods. Hahn presented a useful overview of gas-phase
synthesis of nanocrystalline material. In vapor-phase syn-
thesis, conditions are created where the vapor-phase mix-
ture is thermodynamically unstable relative to formation of
solid material to be prepared in nanoparticulate form [80].
•
Pyrolysis:
In pyrolysis, vaporous precursor is forced
through a hole or opening at high pressure and burned.
h e resulting solid in air is classii ed to recover oxide
particles from byproduct gases.
•
Inert Gas Condensation:
In this process solid material
is heated to evaporate it into a background gas, and then
the vapor is mixed with cold gas to reduce the tempera-
ture. h is method is well suited for production of metal
nanoparticles. Maisels
et al.
prepared nanocomposites of
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