Reinforcing Covalency via d-p-d Orbital Coupling Enables Dual-Site Selective Ozone Activation for Efficient CH₃SH...

Area of Science:

• Environmental Chemistry
• Materials Science
• Catalysis

Background:

• Surface-adsorbed oxygen species (*O/*O2) are crucial non-radical oxidants in catalytic ozonation, but their selective generation is challenging.
• These species enhance pollutant degradation via electron-transfer mechanisms, making their controlled production vital for efficient remediation.

Purpose of the Study:

• To design an amorphous Co-Ni bimetallic oxide catalyst for selective generation of *O and *O2 species.
• To investigate the orbital coupling mechanism responsible for enhanced ozone activation and oxygen species selectivity.
• To evaluate the catalyst's performance in methyl mercaptan (CH3SH) removal under various conditions.

Main Methods:

• Synthesis of amorphous Co-Ni bimetallic oxide (Co0.5Ni0.5) with tailored orbital coupling.
• Characterization using in situ spectroscopy and theoretical simulations to understand electronic structure and reaction mechanisms.
• Performance testing for CH3SH mineralization and removal under different flow rates, humidity, and stability tests.

Main Results:

• The Co0.5Ni0.5 catalyst achieved 100% CH3SH mineralization at high space velocity (600,000 mL h-1 g-1) with 24-hour stability.
• Sustained >95% CH3SH removal over 12 hours under 75% relative humidity due to weak water adsorption and hydrophobicity.
• Demonstrated resistance to sulfur poisoning via balanced Lewis acidity and high surface hydroxyl density.

Conclusions:

• Orbital-level engineering of bimetallic oxides, specifically Co-Ni, enables selective generation of *O/*O2 for efficient volatile organic compound (VOC) remediation.
• The synergistic effect of Co and Ni sites optimizes ozone activation and stabilizes reactive oxygen species.
• This approach offers a promising strategy for developing robust and sustainable catalysts for air purification.