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How do catalysts in automobile exhaust systems help reduce air pollutants?
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catalysis
Nanoparticles of a gold-palladium (yellow-blue) alloy supported on acid-treated carbon (gray) directly catalyzing hydrogen peroxide formation from hydrogen (white) and oxygen (red) while shutting off unwanted hydrogen peroxide decomposition.
A catalytic converter is a vital component of an automobile's emission control system designed to minimize the release of harmful pollutants from the internal-combustion engine.
The device contains a honeycomb structure or pellets coated with a catalyst—often precious metals like palladium or rhodium—which accelerates chemical reactions without being consumed in the process. As exhaust gases pass through this chamber, the catalysts facilitate the following transformations:12
- Oxidation: Harmful hydrocarbons and carbon monoxide are oxidized into relatively harmless water vapour and carbon dioxide.12
- Reduction: Nitrogen oxides are reduced into nitrogen and oxygen, effectively neutralizing these pollutants before they exit the vehicle.12
By converting toxic byproducts into less hazardous substances, these systems play an essential role in reducing environmental pollution.1