High performance ozone decomposition over MnAl-based mixed oxide catalysts derived from layered double hydroxides

Area of Science:

• Materials Science
• Catalysis
• Environmental Chemistry

Background:

• Ozone (O3) decomposition is crucial for air purification.
• Developing efficient and stable catalysts is essential for practical applications.
• Manganese-aluminum mixed metal oxides are potential candidates for catalytic ozone decomposition.

Purpose of the Study:

• To synthesize mesoporous manganese-aluminum oxide (MnAlO) catalysts via layered double hydroxide (LDH) precursors.
• To investigate the effect of Mn/Al ratio and calcination temperature on catalyst properties and performance.
• To evaluate the catalytic activity and stability of the synthesized catalysts for ozone decomposition.

Main Methods:

• Layered double hydroxide (LDH) precursors were prepared using the coprecipitation method.
• MnAlO catalysts were synthesized by calcining LDH precursors at various temperatures.
• Physicochemical properties were characterized using techniques like BET surface area analysis and XPS.
• Catalytic activity for ozone decomposition was evaluated under specific reaction conditions.

Main Results:

• The synthesized MnAlO catalysts exhibited high specific surface area, abundant oxygen vacancies, and low average Mn oxidation states, contributing to excellent catalytic activity.
• The Mn/Al atomic ratio and calcination temperature significantly influenced the textural properties and catalytic performance.
• The Mn₂AlO-400 catalyst (Mn/Al = 2, calcined at 400 °C) achieved 84.8% ozone conversion within 8 hours.
• Catalyst deactivation was observed due to oxygen-related intermediates, but activity was recovered by post-treatment regeneration.

Conclusions:

• Mesoporous MnAlO catalysts fabricated from LDH precursors are effective for ozone decomposition.
• Optimizing the Mn/Al ratio and calcination temperature is key to enhancing catalytic performance.
• The Mn₂AlO-400 catalyst demonstrates promising activity and regenerability for practical ozone decomposition applications.