Energy-efficient CO₂/CO interconversion by homogeneous copper-based molecular catalysts

Area of Science:

• Catalysis
• Green Chemistry
• Bioinorganic Chemistry

Background:

• Efficient conversion of carbon dioxide (CO2) to valuable carbon feedstocks is essential for achieving net-zero carbon emissions.
• Synthetic catalysts often struggle with energy efficiency and selectivity in CO2 reduction.
• Natural enzymes like carbon monoxide dehydrogenase (CODH) offer a blueprint for effective CO2 transformation.

Purpose of the Study:

• To develop a synthetic molecular catalyst that mimics the CODH enzyme for efficient and selective CO2 reduction.
• To investigate the mechanism of reversible CO2 reduction and CO oxidation driven by a molecular complex.
• To explore the role of peripheral functional groups in modulating catalytic activity in different media.

Main Methods:

• Design and synthesis of a molecular copper complex coordinated by redox-active ligands.
• Incorporation of proton-exchanging amine groups into the ligand periphery.
• Detailed spectroelectrochemical analysis to elucidate the catalytic mechanism.

Main Results:

• Demonstration of a synthetic molecular complex driving reversible CO2 reduction and CO oxidation, mimicking natural enzymes.
• Modulation of catalytic bias towards CO2 reduction or CO oxidation by adjusting amine groups and media (organic/aqueous).
• Evidence of synchronous participation of copper, redox-active ligands, and amines in the energy-efficient catalytic cycle.

Conclusions:

• The developed copper complex offers a novel, energy-efficient pathway for CO2 conversion, inspired by the CODH enzyme.
• This catalytic system shows potential for reducing carbon footprints in industrial processes.
• The strategy of using redox-active ligands and peripheral functional groups provides a versatile platform for designing CO2-utilizing catalysts.