Description du sujet de thèse

The synthesis of ammonia using the Haber-Bosch process (HB; N2+ 3 H2→ 2 NH₃) is one of the most important chemical advances of the 20th century.
This process remains the dominant method for producing NH3, currently the second most synthesized chemical in the world. Ammonia is 80% used in the production of inorganic nitrogen fertilizers, and its synthesis remains crucial to global food security. Ammonia is also considered a potential alternative fuel due to its high energy density and ability to be stored and transported relatively easily compared to other hydrogen carriers.
With annual production of over 180 Mt still growing, NH3 synthesis using the HB process is very energy-intensive. Most of the hydrogen used in the process comes from fossil resources, and this technology is responsible for around 1.5% of global annual CO2 emissions and 2% of global energy consumption.
In the current context of reducing greenhouse gas emissions, the historical NH3 synthesis process needs to be rethought.
This project proposes the use of a totally innovative alternative to the HB process for synthesizing NH3, first demonstrated at IC2MP. This approach eliminates the need to use hydrogen (derived from fossil fuels), replacing it with a hydrogen-donating molecule (derived from biomass), using a catalytic hydrogen transfer reaction. This new process allows carbon emissions to be contained to the otherwise recoverable reaction by-products, and theoretically offers much higher yields than the HB process. If successful, it offers a potentially revolutionary ecological prospect for the ammonia chemical industry and its very important economic fabric.

Contexte de travail

The thesis work will be carried out in the SAMCat (Du Site Actif au Matériau Catalytique) team at IC2MP, under the co-direction of Fabien CAN (PU) and Stéphane Célérier (CR, HDR).
The IC2MP is a joint research unit of the CNRS (Chemistry) and the University of Poitiers, bringing together some 250 people, including around a hundred researchers spread over several sites on the university campus.
The SAMCat team comprises around 30 researchers and teacher-researchers, and specializes in the formulation and physico-chemical characterization of catalytic and electrocatalytic materials for energy applications (biofuels, e-fuels, fuel cells, electrolysis, etc.) and environmental applications (water and air pollution control, remediation, etc.).
The decarbonation of ammonia production has been studied by the team for some ten years, using thermo- and electro-catalytic methods.

Contraintes et risques

Risks associated with handling gaseous compounds, mainly NH3.