Méthodes moléculaires pour le stockage d'énergie et la production de carburant

The goal of the CAMELEON project was to develop new molecular, selective and stable catalysts combining multi-electron transfer and metal-ligand cooperative properties, for the reduction of carbon dioxide (CO2) using exclusively Earth abundant, inexpensive 1st row transition metals. In this regard, we reported a molecular MnI-complex describing direct experimental evidence on the correlation of remote interactions between the MnI-complex and different alkali cations with redox potential tuning. Furthermore, we showed the electrochemical behavior of the complex towards carbon dioxide, including the effects of added alkali salts using cyclic voltammetry. Also, we developed a bimetallic system to investigate carbon dioxide electrochemical reduction. The new organic platformed used to stabilize the dinuclear cobalt complex is redox non-innocent, facilitating the electrocatalytic reduction of CO2 to carbon monoxide (CO) in the presence of Brønsted acids. Thus, we took advantage of this metal – to – ligand cooperativity to transform CO2. Our chemical, electrochemical and spectro–electrochemical studies allow us to understand the redox properties of the complex, as well as to observe in situ generation of CO. In the presence of protons, electrocatalytic studies revealed single–site mechanism with up to 94% selectivity towards CO formation, at low overpotentials. After this work, we continued the analysis of bimetallic molecular complexes, moving to study heterobimetallic complexes. We developed a family of new molecular complexes (two monometallic and two bimetallic) stabilized with the same organic platform to study carbon dioxide reduction. Such studies provided experimental evidence that the addition of a second metal in the molecular system has a positive impact towards the reduction of carbon dioxide. Thus, demonstrating bimetallic cooperativity during the process as it occurs in Nature and other bioinspired models.