system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 what is a catalytic converter, what does it do, and why are they constantly being stolen?

Thank you everyone for the very useful input. Single parent here, and between dropping my kids off at school and getting home from work, you've given me a crash course in automotives and chemistry.
gpt
Burning fuel can produce several toxic gases. A catalytic converter is a device that takes those toxic gases and converts them into less toxic gases.

For example, it converts Carbon monoxide into Carbon Dioxide, and Nitric Acid into Nitrogen and Oxygen (and a few other reactions).

In order to do this, it needs some precious metals which act as catalysts for the reactions. These metals don't get consumed, but their presence helps to trigger these reactions. A catalytic converter will contain Rhodium, Platinum, and Palladium. All of these are valuable to scrap metal dealers.

Because they are on the exhaust system, they are outside the body of the car, so they are easy to steal.