Regulating the Layer Stacking Configuration of CTF-TiO₂ Heterostructure for Improving the Photocatalytic CO₂...

Area of Science:

• Materials Science
• Catalysis
• Nanotechnology

Background:

• Developing efficient photocatalysts for CO2 reduction is crucial for addressing climate change.
• Covalent triazine frameworks (CTFs) offer tunable electronic properties for photocatalysis.
• TiO2 is a widely studied but often limited photocatalyst for CO2 conversion.

Purpose of the Study:

• To investigate the effect of CTF stacking modes (AA vs. AB) on TiO2 heterostructures for photocatalytic CO2 reduction.
• To understand the structure-activity relationships governing photocatalytic performance.
• To explore the mechanism of CO2 reduction to methane and CO.

Main Methods:

• In-situ growth of TiO2 on CTF-AA and CTF-AB heterostructures.
• Characterization of heterostructure properties, including light absorption and carrier migration.
• Analysis of interfacial electron transfer using electron density difference and Bader charge analysis.
• Quantification of photocatalytic products (CH4 and CO) using gas chromatography.

Main Results:

• CTF-AA/TiO2 exhibited enhanced light absorption and carrier migration compared to CTF-AB/TiO2 and pristine TiO2.
• CTF-AA/TiO2 achieved significantly higher photocatalytic CO2 reduction rates: 9.19 μmol·g-1·h-1 CH4 and 2.32 μmol·g-1·h-1 CO.
• CTF-AB/TiO2 showed limited CO2 conversion, attributed to insufficient interfacial electron transfer.
• Thermodynamic analysis indicated a preference for CH4 generation over CO in the CTF-AA/TiO2 system.

Conclusions:

• The eclipsed AA stacking of CTFs in CTF-AA/TiO2 heterostructures promotes efficient charge separation and transfer, leading to superior photocatalytic CO2 reduction.
• Interlayer interactions and interfacial electron transfer are critical factors in designing effective photocatalytic systems.
• This work provides insights into rational design strategies for advanced photocatalysts based on CTF/TiO2 heterostructures.