Optimizing localized polarons on Co₃O₄ surface for photo-ozone catalysis

Area of Science:

• Materials Science
• Catalysis
• Environmental Chemistry

Background:

• Photothermal conversion increases temperature, enhancing charge carrier recombination and limiting solar energy use in catalysis.
• Developing efficient photocatalysts is crucial for solar energy utilization and environmental remediation.

Purpose of the Study:

• To synthesize N-doped Co3O4 (Co3O4-FC) via a freeze-straw-capillary-action method.
• To investigate the photo-induced nonthermal effect on the catalytic ozonation of dichloromethane (DCM).
• To enhance solar energy utilization for catalysis by mitigating charge carrier recombination.

Main Methods:

• Synthesis of N-doped Co3O4 using a freeze-straw-capillary-action method.
• Characterization of the material's properties under light irradiation.
• Evaluation of catalytic performance in DCM ozonation at various temperatures.

Main Results:

• N-doping in Co3O4-FC generated stable localized polarons under light, converting Co2+ to Co3+ sites.
• Co3+ sites acted as adsorption and activation sites for DCM, showing a synergistic photothermal and photocarrier effect.
• At 70°C, illumination with Co3O4-FC significantly increased DCM degradation rate (37.8%), mineralization efficiency (163.6%), and ozone utilization (73.7%) compared to Co3O4-blank.

Conclusions:

• A novel photo-induced nonthermal effect was observed in N-doped Co3O4, enhancing DCM catalytic ozonation.
• This pathway offers potential for lowering thermocatalysis temperatures and altering reaction selectivity via light.
• The findings present a new strategy for efficient solar energy utilization in catalytic processes.