This artificial photosynthesis converts CO2 into alcohol and hydrocarbon

Artificial photosynthesis is a highly promising biomimetic process that aims to convert carbon dioxide into valuable carbon-based molecules using solar energy. For this process to be viable, it must be simple and robust, cost-effective, and selective. A significant challenge that a Franco-Vietnamese team of scientists has just overcome using a cobalt complex immobilized on electrode materials.


While carbon dioxide (CO₂) is the main gas responsible for climate change, it is also a valuable carbon source for producing fuels, carbon-based materials, and chemicals that will be needed in a post-petroleum society.

To achieve this, catalytic processes must be developed to convert CO₂ into valuable molecules while using renewable energy sources. These catalytic systems need to be selective, both by producing only one CO₂ conversion product and by avoiding competitive hydrogen production through water decomposition.

Researchers from the SolHyCat team at the Laboratory of Chemistry and Biology of Metals (CNRS/CEA/Université Grenoble Alpes) have demonstrated that by immobilizing a cobalt coordination complex on carbon nanotubes, they obtained a catalytic material for the conversion of CO₂ into carbon monoxide (CO) with more than 90% selectivity, the remaining 10% being hydrogen.

This system is fast and stable with over 20,000 catalytic cycles performed in 2 hours without loss of activity. The CO/H₂ mixture obtained, known as syngas, is a key intermediate for synthesizing a wide variety of products such as alcohols and hydrocarbons.


Even more impressively, the same team, in collaboration with a group from the Franco-Vietnamese University of Hanoi, has integrated the cobalt-based catalyst into a photo-electrochemical cell. This cell uses solar energy to convert CO₂ and water into syngas autonomously.

At the heart of this device, the cobalt catalyst is combined with a photosensitizer to mimic the function of photosynthetic living organisms.

Editor: AVR

References:

Impact of the Surface Microenvironment on the Redox Properties of a Co-Based Molecular Cathode for Selective Aqueous Electrochemical CO₂-to-CO Reduction
Matthieu Haake, Dmitry Aldakov, Julien Pérard, Giulia Veronesi, Antonio Aguilar Tapia, Bertrand Reuillard & Vincent Artero.
J. Am. Chem. Soc. 2024
DOI: https://doi.org/10.1021/jacs.4c03089

Unassisted Solar Syngas Production by a Molecular Dye-Cobalt Catalyst Assembly in a Tandem Photoelectrochemical Cell
Duc N. Nguyen, Emmanouil Giannoudis, Tatiana Straistari, Jennifer Fize, Matthieu Koepf, Phong D. Tran, Murielle Chavarot-Kerlidou & Vincent Artero.
ACS Energy Letters 2024
DOI: https://doi.org/10.1021/acsenergylett.3c02480