Innovative Oxide Catalysts for next PEMFC generatio – InnOxiCat

For preparing the next breakthrough automotive (PEMFC) generation at the horizon 2025-2030, the question of substituting critical raw materials like Pt group metals (PGMs) is mandatory for many reasons. Among them, cost is a major issue: 30% of the PEMFC cost is issued from the use of Pt as catalyst in both electrodes. Besides cost issues, availability of strategic raw materials, such as PGMs only on restricted areas on earth (South Africa and Russia, mainly) makes addressing the substitution of PGMs very urgent. replacement of PGM catalysts requires to address the following three objectives: (i) building knowledge on convenient structures and compositions of non-PGM materials for fuel cell cathodes (where the sluggish oxygen reduction reaction occurs), (ii) synthesizing the materials and characterizing their physicochemical and electrochemical properties and (iii) reaching higher performance than the state of the art of non-PGM materials for the development of next generation PEMFCs. Indeed, the progress accomplished up to now in reducing Pt content in PEMFC does not appear as a sufficient breakthrough for reducing the reliance on critical and strategic raw metals, even if the goal of 0.1 gPt/kW has been (almost) reached.
The objectives of the InnOxiCat project not only concern the development of non-PGM catalysts for the implementation of the next generation of PEMFCs, but moreover intend to create knowledge on novel materials based on computational chemistry (reactive Molecular Dynamics simulations, rMD), associated with their synthesis by combinatorial experimental catalyst screening using reactive magnetron sputtering deposition (RMSD) including gas aggregation source deposition (RM-GASD).
In this context, the InnOxiCat project makes the innovative and challenging choice of developing titanium and zirconium oxide and oxynitride-based catalysts for the oxygen reduction reaction (ORR), titanium and zirconium being more abondant as natural minerals on Earth that platinium (and of course less expensive). To reach the objectives, the development of a synthesis method which could allow controlling the oxygen sub-stoichiometry of the materials is of paramount importance. Plasma sputtering methods are very convenient for the synthesis of such kind of oxides and oxynitride based thin films, because they can span a wide range of compositions.
For these reasons, the InnOxiCat project aims scientifically at: (i) designing new Ti and/or Zr sub-oxide/oxynitride catalysts, using both computational chemistry (rMD) and reactive plasma sputtering deposition, (ii) addressing the objectives of reaching the electrochemical performances and durability targeted by the DoE, and (iii) understanding the electrochemical mechanisms involved in order to better identify the routes to improve the performance and durability of non-PGM catalysts. It will able to propose new breakthrough concepts and robust guidelines for the next fuel cell generation for automotive applications.
Thus, the main expected results of InnOxiCat are:
- New innovative and efficient non-PGM cathode catalysts for PEMFC based on Ti and/or Zr sub-oxide, either O-vacancies or oxynitrides based;
- A general methodology for finding the best non-PGM catalyst by combining predictive atomic scale simulations and advanced characterizations of the catalysts, and single cell testing. Especially, the way for improving mass transport losses reduction, increasing durability will be better understood.