Three -way catalysts will only give full conversion of each of these three pollutants in a gas stream containing a stoichiometric ratio of CO and NOx, as shown in the figure below. There are many reaction pathways in a Three -way catalyst system, including those shown for the . The most important reactions for removing NOx can be summarised as: 2CO+2NO→2CO2+N2 4HC+10NO→4CO2+2H2O+5N2 2CO+2NO→2CO2 4HC+5O2→4CO2+2H2O Excellent substrate High performance Low pressure drop 80,000 km Least Life Time