2025 AIChE Annual Meeting

Multiscale Characterization of Thin Film Oxide Catalysts for Oxygen Evolution Reaction

The oxygen evolution reaction (OER) is a key process in a myriad of clean energy applications; one such example is the increasingly popular metal-air battery, which is often used in electric vehicles1. In this reaction, water is split into molecular oxygen2. However, the performance of OER-based applications is inhibited by the reaction's slow kinetics. While IrO2 and RuO2 have proven to be efficient catalysts, they require high overpotential and are limited in supply, prompting the search for a more suitable catalyst3,4. Furthermore, determining the true intrinsic activity of catalysts independent of their resistances and any incorporated binders and additives is difficult, highlighting the need for a robust characterization method3.

To address these challenges, we aim to develop new thin film oxide catalysts through topotactic oxidation of layered nickelates with tuned properties using molecular-beam epitaxy (MBE)5, and characterize their intrinsic activity using a rotating disk electrode (RDE) and scanning electrochemical cell microscopy (SECCM)6. We employ the RDE at the macroscale level to study the thin films free of additives and binders (and are therefore limited only by sample resistance), with increased mass transport defined by convection at the rotating electrode interface. We use SECCM to further analyze the catalysts in a nanoscale configuration with even higher mass transport and negligible effects from film resistance. We hope that these results will provide distinct structure-activity correlations that can aid the rational design of improved OER kinetics for clean energy applications.

References

1. Zhang, X.; Wang, X.; Xie, Z.; Zhou, Z. Recent progress in rechargeable alkali metal–air batteries. Green Energy and Environment 2016, 1 (1), 4-17.

2. Risch, M.; Suntivich, J.; Shao-Horn, Y. Oxygen Evolution Reaction. Encyclopedia of Applied Electrochemistry; Springer, 2014; pp 1475-1480.

3. Beall, C. E.; Fabbri, E.; Schmidt, T. J. Perovskite Oxide Based Electrodes for the Oxygen Reduction and Evolution Reactions: The Underlying Mechanism. ACS Catalysis 2021, 11 (5), 3094-3114.

4. Seh, Z. W.; Kibsgaard, J.; Dickens, C.F.; Chorkendorff, I.; Nørskov, J.K.; Jaramillo, T.F. Combining theory and experiment in electrocatalysis: Insights into materials design. Science 2017, 355 (6321).

5. Segedin, D.F.; Kim, J.; LaBollita, H.; Taylor, N.K.; Baek, K.; Sung, S.H.; Turkiewicz, A.B.; Pan, G.A.; Jiang, A.Y.; Bambrick-Santoyo, M.; et al. Topotactic oxidation of Ruddlesden-Popper nickelates reveals new structural family: oxygen-intercalated layered perovskites. Condensed Matter 2025,

6. Wahab, O.J.; Kang, M.; Unwin, P.R. Scanning electrochemical cell microscopy: A natural technique for single entity electrochemistry. Current Opinion in Electrochemistry 2020, 22, 120-128.