​​While carbon dioxide (CO₂) is the main greenhouse gas responsible for climate change, it is also foreseen as a key building block for the production of carbon-based fuels, chemicals and materials needed in a post-fossil society. To achieve this transition, we need to develop catalytic processes able to convert CO₂ into valuable base chemicals while using only renewable energy sources. These catalytic systems have to be selective, i.e. producing a single CO₂-conversion product while avoiding any competitive production of hydrogen from water splitting.

Researchers at the team SolHycat from our Laboratory​ have shown that immobilizing a molecular cobalt complex at a carbon nanotube-based electrode generates a catalytic material for the conversion of CO₂ into CO with a selectivity above 90%, the remaining 10% being hydrogen. This system is efficient and stable, with more than 20,000 catalytic cycles achieved in 2 hours without any loss of activity. This CO/H₂ mixture, called syngas, is a key intermediate for the synthesis of a wide variety of products such as alcohols and hydrocarbons.

Moreover, the same team, in collaboration with a group from the Vietnam-France University of Hanoi, has been able to integrate the same cobalt complex into a photoelectrochemical cell that uses only solar energy to convert CO₂ and water into syngas in a fully autonomous way. At the heart of this process is a dyad assembling the cobalt catalyst with a ruthenium-based photosensitizer that mimics the function of photosystems in photosynthetic organisms to enable the production of solar syngas.​​

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