Platinum is a rare element and therefore in demand for use in both
jewelry and as a catalyst. In bulk form, platinum is one of the most
effective but expensive catalysts available. You probably use platinum
as a catalyst every day in the catalytic converter in your car. The
platinum in a catalytic converter helps change air-polluting molecules
from your car exhaust into less harmful molecules.
The atoms in molecules, such as hydrogen, bond with platinum atoms,
and then the platinum atoms release the hydrogen atoms, allowing them to
react with other molecules. By breaking up molecules into atoms,
platinum facilitates chemical reactions and allows them to occur at a
lower temperature than they could without a catalyst. Using
nanoparticles of platinum increases the surface area available for a
reaction and also increases the percentage of platinum atoms available
for contact with molecules involved in the reaction. This difference
allows researchers and manufacturers to use smaller quantities of
platinum, which is important given its high cost.
These improved catalysts have a better capability to break down air
pollutants and also reduce the cost of catalysts used in fuel cells. But
platinum comes at a high price, so nanotechnologists may choose other
options in some cases.
Excerpted from Nanotechnology For Dummies (2nd edition), from Wiley Publishing