What Does The Catalytic Converter Do?

What is a Catalytic Converter?

Catalytic converters are exhaust emission control systems that convert toxic gases and pollutants into less harmful pollutants by catalyzing a redox reaction. Gasoline powered vehicles accomplish this through the use of three-way converters that combine oxygen (O) with carbon monoxide (CO) and unburned hydrocarbons (HC) to produce carbon dioxide (CO2) and water (H2O) and reduce oxides of nitrogen (NOx).

Catalytic Converter Components

  1. Catalyst Support: A solid with a high surface area to which the catalyst is affixed.
  2. Washcoat: Forms a rough, irregular surface on the catalyst support to greatly increase the amount of surface area in order to maximize the amount of catalytically active material that can react with the exhaust gases.
  3. The Catalyst: Typically made of platinum, rhodium and palladium. The catalyst is the material that actually reduces and oxidizes the exhaust gases to chemically change them into less harmful pollutants. Platinum and rhodium cause the reduction, while platinum and palladium cause the oxidation.

catalytic converter

What Chemical Reactions Happen in the Catalytic Converter?

  1. Reduction of nitrogen oxides into elemental nitrogen and oxygen
    1. NOx→Nx+Ox
  2. Oxidation of carbon monoxide to carbon dioxide
    1. CO+O2→CO2
  3. Oxidation of hydrocarbons into carbon dioxide and water
    1. CxH4x+2xO2→xCO2+2xH2O

Check Engine Light Diagnostic Trouble Codes Associated with the Catalytic Converter:




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