Photothermal-Enhanced Anti-SO₂ Performance of a MoWO_x/CeO₂ Catalyst in Low-Temperature NH₃-SCR

Area of Science:

• Catalysis
• Materials Science
• Environmental Chemistry

Background:

• Cerium-based catalysts for ammonia selective catalytic reduction (NH3-SCR) exhibit poor low-temperature activity and SO2 poisoning.
• Developing efficient and SO2-resistant catalysts is crucial for industrial applications.

Purpose of the Study:

• To enhance the low-temperature performance and SO2 resistance of MoWOx/CeO2 catalysts for NH3-SCR using photothermal catalysis.
• To elucidate the underlying mechanisms responsible for the observed improvements.

Main Methods:

• Synthesis and characterization of MoWOx/CeO2 catalysts.
• Evaluation of catalytic performance under photothermal conditions with varying SO2 concentrations.
• In-situ characterization techniques and Density Functional Theory (DFT) calculations.

Main Results:

• Photothermal catalysis achieved over 90% NOx conversion at 200 °C, even with 250 ppm SO2.
• Light irradiation enhanced oxygen vacancies and weakened NO adsorption, favoring the Eley-Rideal mechanism.
• SO2 adsorption intensity decreased, inhibiting ammonium sulfate formation.
• DFT calculations confirmed enhanced electron transfer and suppressed SO2 oxidation under light.

Conclusions:

• Photothermal catalysis is a viable strategy to overcome the limitations of cerium-based catalysts for NH3-SCR.
• The enhanced performance is attributed to improved active site electron density and suppressed SO2 poisoning.
• This study offers a novel approach for designing highly efficient, SO2-resistant catalysts for low-temperature applications.