Three-Way Catalyst
Typical Conversion Efficiencies
| NOx |
CO |
HC |
CH2O |
HAPs |
| 90-99% |
90-99% |
50-90% |
80-95% |
80-95% |
Reactions
|
Oxidation reactions with O2:
|
|
CO + ½ O2 → CO2
HC + ½ O2 → CO2 + H2O
HC + ½ O2 → CO + H2O
H2 + ½ O2 → H2O
|
| Oxidation/reduction reactions with NO: |
|
CO + NO → ½ N2 + CO2
HC + NO → N2+ H2O + CO2
HC + NO → N2 + H2O + CO
H2 + NO → ½ N2 + H2O
H2 + 2 NO → N2O + H2O
5/2 H2 + NO → NH3 + H2O
2 NO + 2 NH3 + ½ O2 → 2N2 + 3 H2O
|
| Water-gas shift reaction: |
|
CO + H2O → CO2 + H2
|
| Reforming reactions: |
|
HC + H2O → CO2 + H2
HC + H2O → CO + H2
|
|