Originally Posted by Burnman
This is not correct. It uses the precious metals to catalyze a reaction not of unburnt fuel, but by-products of imperfect combustion. Principally carbon monoxide to carbon dioxide, and oxides of nitrogen into nitrogen and carbon dioxide. Maybe some unburnt fuel but that is not it's principal feature.
Sure it's from Wiki, but...
"Since 1981, three-way catalytic converters have been used in vehicle emission control systems in North America and many other countries on roadgoing vehicles. A three-way catalytic converter has three simultaneous tasks:
Reduction of nitrogen oxides to nitrogen and oxygen: 2NOx → xO2 + N2
Oxidation of carbon monoxide to carbon dioxide: 2CO + O2 → 2CO2
Oxidation of unburnt hydrocarbons (HC) to carbon dioxide and water: CxH2x+2 + [(3x+1)/2]O2 → xCO2 + (x+1)H2O"
You are probably thinking of the old RX-7 thermal reactor emissions system.
When it says oxidization, it basically is saying 'burning'. It does so by operating at an extremely high heat and it depends on the high heat to continue the reaction. They actually purposely design the fuel system to run rich so that it can continue the burning (oxidization.) That's the hydrocarbons that wiki mentions. It's the unburned fuel.