Nanoparticles: A Brief Overview

1
Nanoparticles A Brief Overview

• What are they?
• How do we characterize them?
• Why are we interested?

2
Nanoparticles What are they?
Nanoparticles are small elemental ensembles
(typically on the nanometer scale). They often
have unique properties due to the fact that they
are do not exhibit the characteristics of the
bulk or individual particles.
3
Synthesis
Typically, the synthesis of nanoparticles is
performed by reducing metal salts in various
ways (electrodeposition, thermolysis,
photochemistry, and chemically). Other methods
include vapor synthesis as well as reduction of
organometallic precursors at high temperatures
(typically in H2 atmosphere).
4
Characterization
X-Ray Absorption Spectroscopy
Microscopy

• Provides information on
• particle size
• particle composition
• (energy dispersive x-ray analysis)

• Provides shell structure information
• nearest neighbors
• bond distances

5
Why are we interested?

• Nanoparticles are of interest for various
  reasons.
• Fundamental perspective
• Allows for study of the the transition from
• bulk properties to those of molecular clusters
• Practical perspective
• Possible application in advanced materials
• (quantum dots, etc.)
• Catalysis applications (due to their small size
  and
• increased surface areas)

6
Surface Area
One intrinsic benefit is the increased surface
area available in nanoparticles.