Three-way catalysts (TWC) effectively convert hydrocarbons, NOx, and carbon monoxide (CO).
In lambda controlled three-way catalysts the following three basic reactions are catalyzed in parallel:
2 NO + 2 CO → N2 + 2 CO2
2 CO + O2 → 2 CO2
2 C2H6 + 7 O2 → 4 CO2 + 6 H2OÂ