Mastering interfacial properties for green hydrogen production
The renewably-powered production of fuels with industrial usage such as hydrogen relies on mastering the kinetics of complex reactions at the electrodes. Indeed, these multistep reactions often involve the concerted exchange of protons and electrons, including the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER), the two half-reactions of water electrolysis.
To master the kinetics for these reactions, we develop an integrated approach relying on the design of efficient and robust catalysts and the fundamental understanding of the events happening at these electrochemical interfaces upon reaction. Our work thus encompasses the development of better Ir-based OER catalysts for proton exchange membrane water electrolyzers; their performances and stability are currently limiting the deployment of this technology (1). Doing so, we unravel a family of oxides which stability in these drastic conditions is granted by a new mechanism involving the bulk exchange of hydrated cations (protons or alkali cations) (2-3). In addition to the development of new catalysts, our research also focuses on understanding the complex dynamics of ions at the electrochemical interfaces and its impact on the kinetics for both the HER and the OER. There, we are developing chemical approaches to confine and selectively study weak interactions of interest as well as to tune the structure of water at long range in order to unravel their importance on the dynamics for water ions transport and on the reactivity of water at the interface (4-5).
1. Lagadec, M. F. and Grimaud, A. Water electrolyzers with closed and open systems, Nature Materials, 2020, accepted.
2. Zhang, R., Dubouis, N., Ben Osman, M., Yin, W., Sougrati, M.T, Alves Dalla Corte, D., Giaume, D. and Grimaud, A. Dissolution/precipitation equilibrium on the surface of iridium-based perovskites as oxygen evolution reaction catalysts in acidic media, Angewandte Chemie International Edition, 58, 4571-4575, 2019.
3. Yang, C., Rousse, G., Svane, K.L., Pearce, P.E., Abakumov, A.M., Deschamps, M., Cibin, G., Chadwick, A.V., Alves Dalla Corte, D., Hansen, H.A., Vegge, T., Tarascon, J.-M. and Grimaud, A. Cation insertion to break the activity/stability relationship for highly active oxygen evolution reaction catalyst, Nature Communications, 11, 1378, 2020.
4. Dubouis, N., Serva, A., Berthin, R., Jeanmairet, G., Porcheron, B. Salager, E., Salanne, M. and Grimaud, A. Tuning the water reduction through controlled nanoconfinement within an organic liquid matrix, Nature Catalysis, 2020, 3, 656-663.
5. Dubouis, N., and Grimaud, A. The hydrogen evolution reaction: from materials to interfacial descriptors, Chemical Science, 10, 9165-9181, 2019.