Single-atom catalysts (SAC) are solid catalysts in which all the active metal atoms are isolated and stabilized on a support, or by an alloy with another metal. The activity is carried by isolated metal atoms, their selectivity is therefore excellent, and the qualities of SACs approach those of homogeneous catalysts while offering the advantages of robustness and ease of handling of solid catalysts. SACs, which allow a high economy of catalytic metals, are good candidates for the implementation of transformations promoting the circular carbon economy and the storage of energy by the hydrogen vector. In particular, they can play an important role for CO2 hydrogenation as well as for hydrogenation and dehydrogenation reactions of liquid organic hydrogen carriers (LOHC), which are an essential element for the transport and storage of energy by the hydrogen vector. However, they remain rather poorly described for these transformations, and the existing examples mostly involve noble metals (Pd, Pt, Au).

The objective of this thesis is twofold. On one hand, it aims at synthesizing and characterizing innovative isolated atom catalysts based on non-noble metals (Ru, Fe, Mn, Co, Cu) capable of catalyzing the reversible hydrogenation of C=O bonds in CO2 and the dehydrogenative coupling of alcohols with water and of alcohols between them. On the other hand, it aims at exploring the possibilities of systems based on alcohol + water/carboxylic acids as LOHC.

The work will consist in synthesizing, characterizing and testing the catalytic activity of different single atom catalysts. The student will be trained in the techniques of synthesis under inert atmosphere, catalysis in pressurized reactors, as well as in the use of various analytical techniques: SEM, HR-TEM, HAADF-TEM, EDX, XPS, XRD