Defect-based Lewis pairs on hydrophobic MnO mesocrystals for robust and efficient ozone decomposition

Area of Science:

• Materials Science
• Environmental Chemistry
• Catalysis

Background:

• Catalytic ozone decomposition is crucial for environmental remediation.
• Developing efficient and stable catalysts, especially under humid conditions, remains a significant challenge.
• Redox-active catalysts with tailored active sites are needed for effective ozone conversion.

Purpose of the Study:

• To develop a novel hydrophobic catalyst for efficient ozone decomposition.
• To investigate the role of manganese vacancies in enhancing catalytic activity.
• To ensure catalyst stability and performance in high humidity environments.

Main Methods:

• Synthesis of hydrophobic carbon-coated mesocrystalline manganese oxide (Meso-MnO@C) with a high density of manganese vacancies (V_Mn).
• Characterization of the catalyst's structure, surface properties, and defect sites (Lewis pairs).
• Evaluation of catalytic performance for ozone (O₃) decomposition under varying humidity levels and high space velocity.

Main Results:

• The developed Meso-MnO@C catalyst exhibited a high density of V_Mn-based Lewis pairs, facilitating electron transfer.
• The hydrophobic carbon coating effectively prevented performance degradation in humid conditions.
• Nearly 100% ozone decomposition was achieved at a high weight hourly space velocity of 1500 L·g^-1·h^-1.
• The catalyst demonstrated rapid reaction kinetics and stable performance for 100 hours at 65% relative humidity.

Conclusions:

• The hydrophobic Meso-MnO@C catalyst with V_Mn-based Lewis pairs is highly effective for ozone decomposition.
• The catalyst's design overcomes the challenge of humidity-induced deactivation.
• This material shows significant potential for practical applications in environmental ozone control.