Dual Active Sites in a Single MOF: Achieving High-Rate and Selective Photocatalytic CO₂ Reduction to Formate With...

Area of Science:

• Materials Science
• Catalysis
• Renewable Energy

Background:

• Artificial photosynthesis requires efficient photocatalysts for both CO2 reduction and water oxidation.
• Integrating these dual functions into a single material remains a significant challenge.

Purpose of the Study:

• To engineer a novel photocatalyst by incorporating ruthenium (Ru(bda)3+) into a CO2-reducing NH2-UiO-66 framework.
• To investigate the dual functionality of the integrated Ru(bda)3+ sites for enhanced visible-light absorption, charge separation, and water oxidation.

Main Methods:

• Defect engineering to integrate Ru(bda)3+ moiety into NH2-UiO-66 framework, creating d-MOF/Ru.
• Photoelectrochemical and in situ X-ray photoelectron spectroscopy (XPS) measurements.
• In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and theoretical calculations.

Main Results:

• The integrated Ru(bda)3+ sites enhanced visible-light absorption and charge separation, acting as active centers for water oxidation.
• The d-MOF/Ru photocatalyst produced HCOOH at a rate of 2157 µmol gcat.-1h-1 with 99.7% selectivity under visible light.
• Performance was 500 times greater than pristine NH2-UiO-66, demonstrating synergistic CO2 reduction and water oxidation.

Conclusions:

• A molecular-level strategy was presented for optimizing photocatalysts for artificial photosynthesis.
• The study offers new perspectives for improving the efficiency of CO2 conversion and water splitting.
• The d-MOF/Ru system showcases a promising approach for sustainable energy solutions.