Optimizing the Carbon Dioxide Reduction Pathway through Surface Modification by Halogenation

Area of Science:

• Materials Science
• Catalysis
• Environmental Science

Background:

• Efficient charge separation in semiconductor photocatalysts is crucial for CO2 reduction.
• Developing advanced materials for sustainable energy conversion remains a significant challenge.

Purpose of the Study:

• To enhance photocatalytic CO2 reduction activity by modifying defect-rich Bi2WO6 nanosheets with halogens.
• To investigate the role of surface halogen modification in CO2 adsorption, activation, and charge separation.

Main Methods:

• Synthesis of halogen-modified defect-rich Bi2WO6 nanosheets.
• Experimental analysis of photocatalytic CO2 reduction.
• Density Functional Theory (DFT) calculations to study reaction mechanisms.
• Evaluation of CO generation rates with and without cocatalysts and sacrificial agents.

Main Results:

• Halogen modification improved CO2 adsorption and activation, and promoted charge separation.
• DFT calculations showed that bromine modification lowers the formation energy of the *COOH intermediate.
• Br-Bi2WO6 exhibited a CO generation rate of 13.8 μmol g−1 h−1, 7.3 times higher than unmodified Bi2WO6.
• With a cocatalyst and sacrificial agent, the CO generation rate for Br-Bi2WO6 reached 187 μmol g−1 h−1.

Conclusions:

• Surface halogen modification is an effective strategy to enhance the photocatalytic CO2 reduction performance of Bi2WO6.
• Bromine modification shows particular promise for accelerating CO2 conversion pathways.
• This work provides a novel approach for designing highly efficient semiconductor photocatalysts for CO2 reduction.