Cobalt-Embedded Metal-Covalent Organic Frameworks for CO₂ Photoreduction

Area of Science:

• Materials Science
• Catalysis
• Environmental Chemistry

Background:

• Growing urgency to reduce carbon footprint necessitates sustainable CO2 mitigation strategies.
• Photocatalytic CO2 reduction is a promising avenue, with catalyst design being crucial for performance.
• Controlling catalytic active sites (CASs) is key to enhancing catalyst efficiency.

Purpose of the Study:

• To report a novel metal-covalent organic framework (MCOF) for photocatalytic CO2 reduction.
• To investigate the performance of MCOF-Co-315 featuring earth-abundant cobalt cocatalysts.
• To elucidate the mechanism of photocatalytic CO2 reduction using advanced spectroscopic techniques.

Main Methods:

• Synthesis of MCOF-Co-315, a metal-covalent organic framework with cobalt.
• Photocatalytic CO2 reduction experiments using Ru(bpy)3Cl2 photosensitizer and triethanolamine (TEOA) sacrificial electron donor.
• Characterization using electron paramagnetic resonance (EPR), X-ray absorption near-edge structure (XANES), and in situ synchrotron Fourier Transform Infrared (FT-IR) spectroscopy.

Main Results:

• MCOF-Co-315 achieved a CO production rate of 1616 μmol g⁻¹ h⁻¹.
• An outstanding apparent quantum yield (AQY) of 9.13% at 450 nm was recorded.
• Spectroscopic studies provided insights into the reaction mechanism.

Conclusions:

• The developed MCOF-Co-315 shows significant potential for efficient photocatalytic CO2 reduction.
• The earth-abundant cobalt cocatalysts and covalent backbone contribute to high catalytic activity.
• Understanding the mechanism aids in designing next-generation CO2 reduction catalysts.