Mixed Catalyst SmMn₂O₅/Cu-SAPO34 for NH₃-Selective Catalytic Oxidation

Area of Science:

• Catalysis
• Environmental Chemistry
• Materials Science

Background:

• Ammonia selective catalytic reduction (NH3-SCR) systems require efficient removal of ammonia slip upstream.
• Low-temperature selective catalytic oxidation (SCO) is a key technology for addressing ammonia slip.
• Developing effective catalysts for low-temperature NH3 SCO remains a significant challenge.

Purpose of the Study:

• To develop novel mixed-phase catalysts for low-temperature ammonia selective catalytic oxidation (SCO).
• To investigate the catalytic performance and mechanism of SmMn2O5/Cu-SAPO34 catalysts for NH3 oxidation.
• To enhance ammonia slip removal efficiency in NH3-SCR systems.

Main Methods:

• Synthesis of mixed-phase SmMn2O5/Cu-SAPO34 catalysts via powder grinding.
• Characterization using XRD, BET, SEM, TEM, XPS, and in situ DRIFTS.
• Evaluation of NH3 oxidation activity under simulated exhaust conditions.

Main Results:

• The 30 wt% SmMn2O5/Cu-SAPO34 catalyst achieved 90% NH3 conversion at 215 °C.
• The mixed-phase catalyst demonstrated reasonable N2 selectivity.
• In situ DRIFTS revealed an internal SCR (i-SCR) mechanism involving NH3 oxidation to NO and subsequent SCR reactions.

Conclusions:

• The developed SmMn2O5/Cu-SAPO34 catalysts exhibit excellent low-temperature activity for NH3 SCO.
• The synergistic effect between SmMn2O5 and Cu-SAPO34 enhances catalytic performance.
• This work presents a viable strategy for designing compound catalysts for efficient low-temperature ammonia oxidation.