NO reduces HNO3 to HONO and surface nitrates to nitrites on a BaNa-Y zeolite, and it reacts with NO2 to form N2O 3. Data are also presented which show that adsorbed NO+ reacts with water to form HONO. In the presence of NH3 and H 2O these processes lead to the formation of ammonium nitrite, which efficiently decomposes near 100°C to N2 + H2O, effecting the catalytic reduction of NOx to N2. A criterion for this path is that the optimum yield of N2 is obtained with an equimolar mixture of NO + NO2. Since ammonium nitrate, which can also form on this catalyst, does not significantly decompose at 200°C, a typical temperature for diesel exhaust, the reduction of nitrate to nitrite serves to regenerate active sites on the BaNa-Y zeolite.
- Ammonium nitrate
- NO reduction mechanism
- Nitrate ions on zeolites
- Nitrate reduction on zeolites
- Nitrous acid
ASJC Scopus subject areas
- Physical and Theoretical Chemistry