Catalytic Converters
- To reduce the amount of pollutants released in car exhaust fumes, many cars are now fitted with catalytic converters
- Precious metals (such as platinum) are coated on a honeycomb to provide a large surface area
- The reactions that take place in the catalytic converter include:
-
- Oxidation of unburnt hydrocarbons:
CnH2n+2 + (3n+1)[O] → nCO2 + (n+1)H2O
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- Oxidation of CO to CO2:
2CO + O2 → 2CO2
or
2CO + 2NO → 2CO2 + N2
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- Reduction of NO to N2:
2CO + 2NO → 2CO2 + N2
Catalytic removal of NOx and CO
- Carbon monoxide and the nitrogen oxides released through cars’ exhaust fumes pollute the atmosphere
- The nitrogen oxides are reduced on the surface of the hot catalyst to form the unreactive and harmless nitrogen gas which is then released from the vehicle’s exhaust pipe into the atmosphere
- The chemical reaction for the reduction of nitrogen oxide to nitrogen gas by the catalyst is as follows:
2CO (g) + 2NO (g) → 2CO2 (g) + N2 (g)
A catalytic converter helps reduce the pollutants from motor vehicles