How is a heterogeneos catalyst used to reduce levels of air pollution from vehicles. Any help will be greatful

Answer 1

Some of the gasoline that exist the chamber of the cylinders in the comustion engine has not completely combusted to CO2 and H2O. If is a complicated mixture of hydrocarbons - oxidixed ketones, aldehydes, carboxlic acids, anhydrides, and unreacted hydrocarbon.

The hetergenous catalysts of the catalystic conveter complete the conversion of these hydrocarbons and by-products to "acceptable" levels of emmisions of CO2, H2O and "hydrocarbons". When you get a smog test they check for all three of these things, each state sets it's own limits for the emission limits for these combustion products.

The catalysts work by using the temperature and pressure of the exhaust gas and the design of the baffles in the converter, to effectively vibrate the molecules apart.

Answer 2

They can be used to catalyse a further oxidation reaction to remove the products of incomplete combustion such as soot, polyaromatic hydrocarbons, carbon monoxide and unburnt fuel (hydrocarbons). The products of these reactions are carbon dioxide and water.

They can also be used to reduce NOx and SOx via a range of reactions that will produce nitrogen, oxygen and maybe ammonia or hydrogen sulphide.

There are also a range of intelligent systems that monitor the composition of the exhaust gases (usually oxygen content) and change the fuel:air mix of the engine accordingly to reduce pollution directly and/or help provide the best mix of gases to the catalysts to allow them to work most effectively.

Answer 3

The catalytic converter, that is used in all of our petrol-run cars, is a heterogeneos catalyst, because it is solid and it is used for reactions with gases. The platinum in the converter helps to eliminate noxious gases like CO or NO by makig them react in the following way:
2CO + 2NO ----> 2CO2 + N2
You will find a lot more information about this in Wikipedia

Answer 4

Heterogeneous means that the catalyst and reactants are in a different state of matter (solid, gas, liquid.). in a catalytic converter, the catalysts are solid and the reactants gaseous. You do the rest of the chemistry.