How does an exhaust catalytic converter work?

A catalytic converter, or 'cat,' has been a standard feature in vehicle exhaust systems since around the 1990s. Its main purpose is to reduce harmful exhaust gases produced by internal combustion before they are released into the atmosphere.

The catalytic converter works by converting harmful exhaust gases, such as nitrogen oxides, carbon monoxide, and hydrocarbons, into less harmful ones as they pass through it.

Inside a stainless steel casing, there's a ceramic monolith with a honeycomb structure. This design allows for free airflow and a maximum surface area, which is coated with precious metals like platinum, palladium, and rhodium. This coating is crucial for the conversion of exhaust gases.

Exhaust gases, including pollutants, enter the catalytic converter and pass through the monolith. A chemical reaction occurs due to the precious metal coating acting as a catalyst. This reaction happens once the converter reaches its operating temperature of around 300 degrees Celsius, transforming the harmful gases into less harmful ones like carbon dioxide, nitrogen, and water, which are then expelled from the tailpipe.