Catalytic Converter: Catalytic converters provide another way to treat the exhaust gas. These devices located in the exhaust system, convert harmful gases into harmless gases. Inside the catalytic converter, the exhaust gases Passover a catalyst. A catalyst is a material that promotes a chemical reaction without being affected by the reaction. In effect, the catalyst encourages chemicals to react with each other.

Converter systems with both oxidation and reduction catalysts are called 2 stage or 3-way catalytic converter systems. The three way catalytic converter is the most ideal type of catalytic converter since it can convert not only CO and HC, but also NOX into non-polluting substances.
Some of the newest converters have even started to use gold mixed with the more traditional catalysts. Gold is cheaper than the other materials and could increase oxidation, the chemical reaction that reduces pollutants, by up to 40 percent.
The oxidizing converter handles HC and CO, using platinum or palladium as the catalysts. The air helps the oxidizing catalyst convert the HC and CO into carbon dioxide and water. The reducing converter handles NOX using metal rhodium. It splits oxygen from the nitrogen. The NOX becomes harmless nitrogen (N2 ) and Oxygen (O2 )