Novel Core-Shell (ε-MnO₂/CeO₂)@CeO₂ Composite Catalyst with a Synergistic Effect for Efficient Formaldehyde Oxidation

Area of Science:

• Materials Science
• Catalysis
• Environmental Chemistry

Background:

• Formaldehyde (HCHO) is a common indoor air pollutant with significant health implications.
• Developing efficient and stable catalysts for HCHO oxidation at low temperatures remains a challenge.
• Core-shell structured catalysts offer unique properties for enhanced catalytic activity.

Purpose of the Study:

• To synthesize a novel core-shell (ε-MnO2/CeO2)@CeO2 composite catalyst.
• To investigate its application in high-efficiency oxidation removal of formaldehyde (HCHO).
• To elucidate the synergistic mechanism behind its excellent catalytic performance.

Main Methods:

• One-pot hydrothermal reaction to prepare the (MnCO3/CeO2)@CeO2 precursor.
• Thermal decomposition of the precursor to obtain the final core-shell catalyst.
• Characterization using XRD, Raman, BET, TEM, and XPS.
• Testing catalytic performance for HCHO oxidation under specific gas conditions and temperatures.

Main Results:

• The (ε-MnO2/CeO2)@CeO2 catalyst achieved 100% HCHO conversion at 80 °C.
• High stability was observed, with >95% conversion maintained for 72 hours and >73.8% for 140 hours.
• Synergistic effects were confirmed, linked to oxygen vacancies on CeO2 and tunable Mn-O bond strength in ε-MnO2.

Conclusions:

• The core-shell (ε-MnO2/CeO2)@CeO2 composite catalyst demonstrates superior performance for HCHO removal.
• The catalyst exhibits remarkable stability at low temperatures and high gas flow rates.
• Optimizing synthesis conditions to enhance oxygen vacancies and Mn-O bond strength is key to catalyst efficacy.