Selective visible-light-driven CO2 reduction on a p-type dye-sensitized NiO photocathode

Area of Science:

• Electrochemistry
• Photocatalysis
• Biocatalysis

Background:

• Efficient conversion of carbon dioxide (CO2) is crucial for sustainable energy and chemical production.
• Developing catalysts that operate efficiently under mild conditions, such as visible light, remains a significant challenge.

Purpose of the Study:

• To design and characterize a photocathode assembly for the selective reduction of CO2 to CO.
• To investigate the performance of the assembly at potentials below thermodynamic equilibrium.
• To explore the role of a semiconductor-enzyme interface in electrocatalysis.

Main Methods:

• Fabrication of a photoelectrode using a porous p-type nickel oxide (NiO) semiconductor.
• Modification of the NiO electrode with a visible-light-responsive organic dye (P1) and carbon monoxide dehydrogenase (CODH) enzyme.
• Electrochemical characterization of the direct electrochemistry between NiO and CODH.

Main Results:

• The photocathode successfully facilitated visible-light-driven selective reduction of CO2 to CO.
• The system operated effectively at potentials below the thermodynamic equilibrium in the dark.
• Electrocatalytic behavior was rectified towards CO oxidation in the dark, influenced by carrier availability at the semiconductor-catalyst interface.

Conclusions:

• The developed photocathode assembly demonstrates a promising approach for efficient CO2 conversion.
• The integration of organic dyes and enzymes with semiconductor materials offers new avenues for photocatalytic applications.
• Understanding the semiconductor-catalyst interface is key to optimizing electrocatalytic performance.