Catalytic converter surface, illustration. A catalytic converter converts harmful polluting gases from a motor vehicle's engine into relatively harmless ones. It consists of a honeycomb structure made of a ceramic, which provides a large surface area shown here. The surface is lined with the catalyst, which is a combination of rhodium (Rh) and platinum (Pt) metals. On the rhodium, nitrogen oxides (nitric oxide, NO, red and blue) are reduced to nitrogen (N2, blue) and oxygen (O2, red). On the platinum, carbon monoxide (CO, red and grey) reacts with oxygen (red) to form carbon dioxide (CO2, red and grey). These gases are then emitted in the exhaust. |