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Operando Catalysis: An Insight through Field Ion Microscopy and Atom Probe Methods

par Visart de Bocarmé, Thierry
Référence Atom Probe Tomography User Meeting 2026 (11: 2026-05-19 - 2026-05-21: Düsseldorf)
Publication Non publié, 2026-05-19

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Résumé :

This conference presentation, entitled Operando Catalysis: An Insight through Field Ion Microscopy and Atom Probe Methods, discusses how field emission microscopies and atom-probe-related techniques can provide unique insights into catalytic surface reactions under working conditions. The talk focuses on the use of Field Electron Microscopy (FEM), Field Ion Microscopy (FIM), and Pulsed Field Desorption Mass Spectrometry (PFDMS) to study model catalytic nanoparticles, represented by sharp metallic tips. A central theme is the influence of strong external electric fields on surface processes. Using the reaction between hydrogen and oxygen on rhodium as a case study, the presentation shows that electric fields can significantly modify surface reconstructions, adsorption behaviour, bistability, hysteresis, and reaction pathways. In particular, the work highlights the coexistence of Langmuir–Hinshelwood and Mars–van Krevelen-type mechanisms, with possible involvement of surface or subsurface rhodium oxide species. The presentation also emphasizes that field effects become especially important at low temperatures, where small changes in the electric field strongly shift the transition between hydrogen-covered and oxygen-covered surface states. At higher temperatures, kinetic oscillations are observed under field conditions, suggesting that an additional field-associated mechanism may be involved. Finally, the talk presents atom-probe-inspired methods as powerful tools for combining structural imaging, dynamic observation, and local chemical analysis during catalysis. These approaches make it possible to probe surface composition, detect ionic species such as water-related ions and rhodium oxides, and investigate the role of oxides and adsorbates in catalytic reactions. The presentation concludes by positioning atom-probe FIM and related environmental atom probe developments as promising methods for operando catalysis and for studying electric-field effects in heterogeneous catalysis.