Van Marum Colloquium: Ryuhei Nakamura & Hideshi Ooka
- Wednesday 21 June 2023
2333 CC Leiden
Ryuhei Nakamura: Extending the Lifetime of Oxygen Evolution Catalysis in Acid
Water electrolysis is a promising method to produce hydrogen from renewable electricity. However, the development of 3d metal catalysts for the oxygen evolution reaction (OER) is a critical challenge, especially in the case of polymer electrolyte membrane (PEM) electrolyzers, which are considered one of the most efficient electrolysis systems. The scarcity of iridium required for these systems prevents their widespread deployment at the global terawatt scale, and therefore the development of alternative catalysts has been highlighted as a true bottleneck for water electrolysis. In this talk, I will report on how the lifetime of Mn-based catalysts in acid can be extended by modulating the lattice oxygen structure. I will also present the performance of Mn-based OER catalysis under the real conditions of PEM water electrolysis (1-3).
- A. Li, S. Kong, C. Guo, H. Ooka, K. Adachi, D. Hashizume, Q. Jiang, H. Han, J. Xiao, R. Nakamura, Enhancing the stability of cobalt spinel oxide towards sustainable oxygen evolution in acid, Nat. Catal., 2022, 5, 109-118, DOI: 10.1038/s41929-021-00732-9
- A. Li, H. Ooka, N. Bonnet, T. Hayashi, Y. Sun, Q. Jiang, C. Li, H. Han, R. Nakamura, Stable potential windows for long-term electrocatalysis by manganese oxides under acidic conditions, Angew. Chem., Int. Ed., 2019, 58, 5054-5058. DOI: 10.1002/anie.201813361
- S. Kong, et al (under revision)
Hideshi Ooka: Theoretical Advancements towards Predicting the Activity and Stability of Electrocatalysts using Microkinetics and Applied Mathematics
Electrocatalysis is expected to play a critical role towards the transition to clean energy technology. So far, thermodynamic insight such as the Sabatier principle and the CHE model has been used as an overarching framework to rationalize why some materials are more efficient than others. However, it is difficult to rationalize kinetic factors such as Tafel slopes or metastability using thermodynamics alone. In this presentation, I will talk about my ongoing attempt to expand the existing theory of electrocatalysis using microkinetics and applied mathematics. In particular, I will talk about how the binding energy which yields maximum activity may shift with the overpotential, and also about how there may be a mechanism-independent tradeoff between activity and stability.