Originally Posted by 2010 WRX Limited
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.
Last time I checked, Carbon Monoxide was not a fuel. Cats are not oxidizing NOX. Nor was my car designed to run rich at normal driving conditions. If they need more heat in the catalyst, they would actually run leaner to elevate EGTs. If all they did was burn there would be no need for the expensive precious metals, and they wouldn't be catalyzing
anything. Unburnt fuel is primarily dealt with by the EGR system.