Selective CO₂-to-CH₄ Photocatalytic Reduction via Spin-Modulation in a Metal─Carbon-Bonded MOF

Area of Science:

• Materials Science
• Catalysis
• Photochemistry

Background:

• Selectivity challenges in photocatalysis hinder efficient CO2 reduction.
• Spin modulation of electronic structure is a promising strategy to enhance photocatalyst performance.

Purpose of the Study:

• To develop a novel metal-organic framework (MOF) based photocatalyst for CO2 reduction.
• To investigate the effect of spin state modulation on photocatalytic activity and selectivity.

Main Methods:

• Synthesis of a novel ruthenium-carbon-bonded MOF (RuCMOF).
• Construction of a heterojunction between RuCMOF and Cu2O nanoparticles.
• Photocatalytic CO2 reduction using water vapor under visible light irradiation.
• Experimental and theoretical studies (e.g., DFT) to elucidate reaction mechanisms.

Main Results:

• The optimized RuC-MOF/10%Cu2O heterojunction exhibited a high CH4 production rate (663.6 µmol g-1 h-1) and selectivity (96.7%).
• Apparent quantum yield reached 4.6% at 400 nm.
• Atomic dispersion of Ru units and heterostructure facilitated efficient carrier separation.
• Cu2O incorporation induced spin transition in Ru centers, suppressing charge recombination via spin-selective electron transfer.
• Spin-state modulation weakened CO adsorption and lowered the energy barrier for CHO formation.

Conclusions:

• Spin polarization engineering in metal-carbon-bonded MOFs is a viable strategy for high-performance photocatalysis.
• The RuCMOF/Cu2O heterojunction demonstrates significant potential for efficient and selective CO2 reduction.
• Understanding spin-state effects provides new avenues for designing advanced photocatalysts.