Probing catalytic surfaces by correlative scanning photoemission electron microscopy and atom probe tomography

Schweinar K, Nicholls RL, Rajamathi CR, Zeller P, Amati M, Gregoratti L, Raabe D, Greiner M, Gault B, Kasian O (2020)

Publication Type: Journal article

Publication year: 2020

Journal

Journal of Materials Chemistry A Royal Society of Chemistry

Book Volume: 8

Pages Range: 388-400

Journal Issue: 1

DOI: 10.1039/c9ta10818a

Abstract

The chemical composition and the electronic state of the surface of alloys or mixed oxides with enhanced electrocatalytic properties are usually heterogeneous at the nanoscale. The non-uniform distribution of the potential across their surface affects both activity and stability. Studying such heterogeneities at the relevant length scale is crucial for understanding the relationships between structure and catalytic behaviour. Here, we demonstrate an experimental approach combining scanning photoemission electron microscopy and atom probe tomography performed at identical locations to characterise the surface's structure and oxidation states, and the chemical composition of the surface and sub-surface regions. Showcased on an Ir-Ru thermally grown oxide, an efficient catalyst for the anodic oxygen evolution reaction, the complementary techniques yield consistent results in terms of the determined surface oxidation states and local oxide stoichiometry. Significant chemical heterogeneities in the sputter-deposited Ir-Ru alloy thin films govern the oxide's chemistry, observed after thermal oxidation both laterally and vertically. While the oxide grains have a composition of Ir0.94Ru0.06O2, the composition in the grain boundary region varies from Ir0.70Ru0.30O2 to Ir0.40Ru0.60O2 and eventually to Ir0.75Ru0.25O2 from the top surface into the depth. The influence of such compositional non-uniformities on the catalytic performance of the material is discussed, along with possible engineering levers for the synthesis of more stable and reactive mixed oxides. The proposed method provides a framework for investigating materials of interest in the field of electrocatalysis and beyond.

Involved external institutions

Elettra Sincrotrone Trieste S.C.p.A. IT Italy (IT) Max-Planck-Institut für Chemische Energiekonversion (MPI CEC) / Max-Planck-Institute for Chemical Energy Conversion DE Germany (DE) Max-Planck-Institut für Eisenforschung GmbH (MPIE) / Max Planck Institute for Iron Research DE Germany (DE)

How to cite

APA:

Schweinar, K., Nicholls, R.L., Rajamathi, C.R., Zeller, P., Amati, M., Gregoratti, L.,... Kasian, O. (2020). Probing catalytic surfaces by correlative scanning photoemission electron microscopy and atom probe tomography. Journal of Materials Chemistry A, 8(1), 388-400. https://doi.org/10.1039/c9ta10818a

MLA:

Schweinar, Kevin, et al. "Probing catalytic surfaces by correlative scanning photoemission electron microscopy and atom probe tomography." Journal of Materials Chemistry A 8.1 (2020): 388-400.

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