What is in a catalytic converter?

A catalytic converter works by the various precious minerals and metals inside it. Quite simply they convert the dangerous chemicals inside the exhaust gases(carbon monixide,NOx etc) into less harmful ones (carbon dioxide etc). Due to the minerals and metals inside though they are often target to thieves as they can fetch quite a high price at the scrap yard. The catalytic converters that got stole off the HGV's at our work had a value of £800!
Catalytic converters work by having the heated gases react with the precious metals in the catalytic converter. There is platinum palladium and rhodium in a catalytic converter all three are very expensive and rare metals. Because of the honeycomb shape of the catalytic biscuit there is a lot of surface area for the gas to be neutralized on.

Prior to catalytic converters being on every car for every mile you drove your car would punch out somewhere around 100g's of pollution. After the addition of catalytic converters with platinum and palladium this number dropped to less than 1g of pollution per mile. After the addition of rhodium it dropped N/E which is non detectable.