Zeolite Y modified with palladium as effective catalyst for selective catalytic oxidation of ammonia to nitrogen

• Catalyst Pd/HY (1.5%) was found to be active and selective in the NH3-SCO process.
• NH3-SCO process over Pd-zeolites proceeds according to the i-SCR mechanism.
• Pd-oxide species are active for NH3 oxidation to nitrogen oxides NO and NO2.
• Part of ammonia is stabilized against oxidation over the zeolite acid sites.

Zeolites HY modified with palladium (0.05–2.5 wt.%) were found to be active and selective catalysts in the process of the selective oxidation of ammonia to nitrogen (NH3-SCO). Parent zeolite and its modifications with palladium were investigated with regard to their structural, textural, and redox properties. The IR spectroscopy, X-ray diffraction, and BET methods were employed for these purposes. Correlation between loading and aggregation of Pd-species deposited on zeolites and their activity and selectivity in the NH3-SCO process was found. Studies of adsorption forms of ammonia and product of its conversion done by IR spectroscopy as well as catalytic tests performed with various space velocities gave insight into the reaction mechanism. Zeolite Y modified with palladium is an interesting catalyst of selective ammonia oxidation for potential application in diesel car exhaust gas purification system.

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