1. Substrate:
* Ceramic honeycomb: This acts as a framework to maximize surface area for the catalytic reaction. The honeycomb structure allows exhaust gases to flow through it efficiently, maximizing contact with the catalyst.
* Metallic substrate: Less common, but some converters use a metallic substrate, often made of stainless steel, for its durability.
2. Catalytic coating:
* Precious metals: This is where the magic happens. These metals, typically platinum, palladium, and rhodium, act as catalysts. They facilitate the chemical reaction that transforms harmful pollutants in the exhaust into less harmful gases.
* Washcoat: This is a thin layer of ceramic or metal oxide that binds the precious metals to the substrate and provides a larger surface area for the reaction to occur.
* Oxides: Additional metal oxides (like cerium oxide) can be added to the washcoat to improve the catalyst's performance and longevity.
3. Housing:
* Steel: This is the outer shell that protects the catalytic converter and connects it to the exhaust system.
In summary, a catalytic converter is essentially a ceramic honeycomb structure coated with precious metals that are carefully designed to efficiently convert harmful pollutants in the exhaust gas into less harmful substances.
