Catalytic Converter

Catalytic converter is a device used in an exhaust system of an engine to control air pollution. It works by using a catalyst to create a chemical reaction in which toxic gases are converted into less harmful gases. These are mainly used in exhaust system of vehicles fueled by petrol or diesel, generators, mining equipments etc. It was invented by Eugene Houdry, a French mechanical engineer and expert in catalytic oil refining.

     During the combustion of fuel, toxic gases like nitrogen oxides, carbon monoxide and hydrocarbons (unburned & partialy burned fuel) are formed. These gases and particles are converted into less harmful gases through a redox reaction in a catalytic converter before it enters into atmosphere.

Chemical Reaction in a catalytic converter

Nitrogen oxides are converted into Nitrogen(N2) through reduction process,
2CO + 2NO → 2CO2 + N2
Hydrocarbons + NO → CO2 + H2O + N2
2H2 + 2NO → 2H2O + N2

Carbon monoxide is converted into carbon dioxide through oxidation,
2CO + O2 → 2CO2

Hydrocarbons are converted into carbon dioxide and water through oxidation,
Hydrocarbons + O2 → H2O + CO2

     Some unwanted reactions, such as formation of hydrogen sulfide and ammonia can occur along with above useful reactions. These can be limited by adding Nickel or Manganese to the wash coat (part inside a catalytic converter to disperse catalytic materials). Both substance prevents the absorbtion of Sulfur by the wash coat.