Résumé : Heterogeneous catalysis is of the pillar of chemical industry, playing a key role in the optimization of chemical processes and their conversion towards “green chemistry”. Physics governing the surface chemical reactions involved in heterogeneous catalysis depends on the synergistic interactions existing between reactants and specific surface structures composing the catalyst. The design of highperformance catalysts requires a deep understanding of those mechanisms at the nanoscale; and surface science techniques are continuously pushing their technical limitations to bridge gaps between fundamental research and real-world applications. In the past decade, an increasing number of analytical techniques successfully achieved their evolution towards an in situ and operando version of themselves, and recently such approaches are being developed for atom probe microscopy (APM) techniques1,2. In this work, we will present the recent advances in the conversion of Atom Probe Tomography (APT) to study surface dynamics of O2/Fe using two different APM techniques and modifications: Field Ion Microscopy (FIM), and Operando Atom Probe (OAP).