Promoting CO₂-to-CO Photoconversion by Regulating Electron Transfer in Heterojunctions.

Area of Science:

• Materials Science
• Catalysis
• Environmental Chemistry

Background:

• Photocatalytic reduction of carbon dioxide (CO2) is a promising strategy for sustainable energy and environmental remediation.
• Developing efficient and stable photocatalysts is crucial for converting CO2 into valuable chemical feedstocks.
• Heterojunction structures can enhance photocatalytic performance by improving charge separation and transfer.

Purpose of the Study:

• To synthesize and characterize a novel Bi2O3/Mn3O4 heterojunction composite photocatalyst.
• To investigate the photocatalytic performance of the composite for CO2 reduction into low-carbon hydrocarbons.
• To elucidate the mechanism underlying the enhanced catalytic activity.

Main Methods:

• Synthesis of Bi2O3/Mn3O4 heterojunction composite photocatalyst.
• Photocatalytic reduction experiments under aqueous phase and sacrificial-agent-free conditions.
• Characterization using techniques such as in situ infrared spectroscopy and Fourier transform infrared spectroscopy (FT-IR).

Main Results:

• The Bi2O3/Mn3O4 composite achieved efficient photocatalytic reduction of CO2 to CO and CH4.
• A CO yield of 10.164 μmol·g−1·h−1 and CO selectivity of 76.04% were obtained.
• Total selectivity for C1 products reached 94.3%, with the heterojunction structure promoting carrier separation and bimetallic synergy enhancing activity.

Conclusions:

• The Bi2O3/Mn3O4 heterojunction composite exhibits excellent photocatalytic performance for CO2 reduction.
• The study highlights the importance of heterojunction engineering and bimetallic synergistic effects in enhancing photocatalytic activity.
• The findings propose a strategy for improving photocatalyst design by modulating electron transfer capabilities.