Thesis Title: Development of a Co-based molecular engineered cathode for CO2 reduction: From the fundamental study of a grafted catalyst to electrolyser integration.
Along with the development of batteries and water electrolysis, electrocatalytic CO2 valorisation is another promising route to achieve efficient storage of renewable electricity produced intermittently by solar and wind farms. In the context of the carbon cycle closure, this approach focuses on the production of high added value chemicals and fuels that can easily be integrated in the current energy mix. Coupled to CO2 capture devices, this strategy will help limit and control the rise in CO2 levels in the atmosphere. Over the past years, our group has been developing molecular structures with catalytic activities towards the valorisantion of CO2, mainly allowing the production of carbon monoxide (CO) and formate with reasonable but improvable selectivity, activity and stability.To overcome current limitations, our group aims to develop more complex and multifunctional matrices to enhance the catalytic activity of individual molecular catalytic sites. Initially, this project focused on the molecular engineering of a well-known catalyst for electrocatalytic CO2 reduction, with the goal of enabling its direct integration onto electrode surfaces. This approach allowed the assessment of the performance of the novel hybrid catalyst in electrocatalytic CO2 reduction to CO, achieving high selectivity (over 95%) and activity at low overpotential. Given the promising activity of this hybrid catalyst, it was subsequently integrated into a gas diffusion electrode for implementation in operational CO2 electrolysers. This approach enables the investigation of the novel catalytic system in a functional electrolyser setup that closely mimics real-world conditions. This offers valuable insights into the system's potential for scale applications. Once integrated into the electrolyser device, the catalyst again demonstrated excellent CO2 reduction activity and selectivity towards CO (of over 97%). However, maintaining catalyst stability during electrolysis remains a key challenge, as degradation can result in significant losses in both activity and selectivity. To address this issue, we identified the deactivation mechanism of the novel hybrid catalyst, enabling the future design of more stable molecular hybrid catalysts..
Key words: Molecular Catalysis, Carbon Nanotubes, Coordination Chemistry, CO2 Valorisation, Supported Electrocatalysis
Doctoral School: ED CSV – Chemistry and Life Sciences
Research laboratory: Laboratoire Chimie et Biologie des Métaux (LCBM - CEA/CNRS/UGA)
Thesis supervision: Vincent ARTERO and Bertrand REUILLARD
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