New catalysts for SAFe HYdrogen Release and use – SAFHYR

A first task will be devoted to the development of catalysts for the transfer hydrogenation reaction and for the direct isopropanol fuel cell. Reducing the use of noble metals will be a key focus of the catalyst design in both cases, with the use of optimized bimetallic or non-noble catalysts. The catalysts will be fully characterized and used in the transfer hydrogenation reaction and in the electrochemical oxidation of isopropanol. The first reaction will initially be studied in an autoclave at different operating conditions in order to determine the activity/selectivity of the different catalysts and to select the most appropriate one under specific conditions. In parallel, the electrocatalysts will be evaluated for their activity and stability in the electrooxidation of isopropanol with particular attention to the selectivity of the oxidation reaction. For both reactions, after the selection phase, further experiments will be performed in (semi-)continuous reactors and in fuel cells, respectively. The design of the most suitable reactors and the feasibility of using this concept in a future integrated process will be evaluated in a final task after thermodynamic and kinetic modeling, thanks to the collection of data from all experiments.

In a first phase, the kinetics of hydrogen storage in dibenzyltoluene was studied, generating perhydrodibenzyltoluene which will transfer its hydrogen to isopropanol.

Synthesis of catalysts for reactions of interest will begin in 2023 with the recruitment of non-permanents assigned to these tasks.

Ji, X.; Meille, V.; Pitault, I.
Novel system of hydrogen storage and transfer in the absence of molecular hydrogen, oral communication at «2ème Journées plénières FRH2«, Aussois, may 2022.

Green hydrogen can be used as an energy carrier. Stored by hydrogenation in Liquid Organic Hydrogen Carriers (LOHC), its transport becomes safe and the storage capacity exceeds that of liquefied or compressed hydrogen at 700 bars. On request, it can be restored in molecular form by catalytic dehydrogenation, highly endothermic, to power a fuel cell.
An alternative and innovative process consists in carrying out, from perhydrodibenzyltoluene as a hydrogen-rich compound, a transfer hydrogenation of acetone, producing dibenzyltoluene and isopropanol, the latter one feeding a direct isopropanol fuel cell (DIPAFC). Both pairs perhydrodibenzyltoluene/dibenzyltoluene and acetone/isopropanol operate in closed-loop while only hydrogen can enter and exit the loop. This process, athermic and safe (no molecular hydrogen is released) could be a significant scientific breakthrough. However, the success of this idea relies on the development of catalysts that perform transfer hydrogenation in a very selective manner, without by-products and deactivation. At the fuel cell level, the choice of electrocatalysts will also drive the selectivity of the electrooxidation of isoproponol, acetone being the only one desired product. Besides, the reactor design is also a key point for the implementation of the concept.

A first task will be dedicated to the development of catalysts for the transfer hydrogenation reaction and for the direct isopropanol fuel cell. Minimizing the use of noble metals will be a key point for the catalyst design in both cases, with the use of optimized bimetallic or non noble metal catalysts. The catalysts will be fully characterized and used in the transfer hydrogenation reaction and in the electrochemical oxidation of isopropanol. The former reaction will be first studied in an autoclave at various operating conditions to screen the activity/selectivity of the different catalysts and select the most appropriate one in specific conditions. In parallel, the electrocatalysts will be evaluated for their activity and stability in the electrooxidation of isopropanol with a special care to the selectivity of the oxidation reaction. For both reactions, after the screening phase, further experiments will be performed in (semi)continuous reactors and in fuel cells, respectively. The design of the most appropriate reactors and the feasibility of using this concept in a future integrated process will be evaluated in a final task after thermodynamic and kinetic modeling, thanks to the collection of data from all the experiments.

The project gathers 3 academic teams from Lyon, with complementary experience/skills in catalysis, chemical engineering, and electrochemistry which will guarantee the success of the project.