Green Chemistry and Nanochemistry

Green Chemistry

Introduction to Nanotechnology

1) Color: It is an optical property that varies at nanoscale.

2) Surface area: Surface to volume ratio is one of the important characteristic of nanoparticles. If a bulk material is divided into several nanoparticles, volume remains the same but the surface area increases .Larger is the surface area, more is the chemical reactivity.

3) Catalytic activity: As the size decreases, surface area increases and hence, nanoparticles have increased catalytic activity. For example: Pd and Pt nanoparticles are used as catalysts in hydrogenation of alkenes and alkynes. TiO₂ and ZnO are used as photocatalysts. Gold nanoparticles are good catalysts for various organic reactions.

4) Melting point: The melting points of nanoparticles depends on size. As the number of atoms in a cluster increases, melting point also increases.

5) Mechanical strength: Nano sized particles are harder than bulk materials. Eg: copper and palladium clusters are 500% harder.

6) Electrical conductivity: Electrical conductivity changes at nanoscale.
 

Synthesis of nanoparticles

There are two approaches for the synthesis of nanoparticles:

• Bott…