Asymmetric oxygen vacancy promotes CO-SCR performance on defect-engineered Rh/CeCuO_x catalyst

Area of Science:

• Catalysis
• Environmental Chemistry
• Materials Science

Background:

• Selective catalytic reduction of nitrogen oxides (NO_x) with carbon monoxide (CO) is vital for purifying exhaust gases.
• Efficient NO_x removal relies on the catalytic cleavage of NO on the catalyst surface.
• Oxygen vacancies play a critical role in facilitating NO cleavage and accelerating the CO-SCR reaction.

Purpose of the Study:

• To synthesize Rh/CeCuO_x catalysts with tailored asymmetric oxygen vacancies.
• To investigate the effect of these vacancies on NO_x purification via CO-SCR.
• To optimize catalyst performance for enhanced NO_x removal.

Main Methods:

• Co-crystallization and impregnation methods for Rh/CeCuO_x catalyst synthesis.
• Hydrogen thermal treatment to induce asymmetric oxygen vacancies.
• Performance evaluation of CO-SCR using various characterization techniques.

Main Results:

• The Rh/Ce_0.95Cu_0.05O_x-H₂ catalyst demonstrated superior CO-SCR performance.
• Achieved over 90% NO_x conversion at 162 °C.
• Hydrogen treatment successfully generated asymmetric oxygen vacancies, promoting NO cleavage.

Conclusions:

• Asymmetric oxygen vacancies effectively accelerate NO cleavage on the catalyst surface.
• This strategy enhances the CO-SCR process by preventing nitrate formation.
• The study presents a novel method for constructing oxygen vacancies in CO-SCR catalysts.