Thierry Epicier Univ Lyon, INSA-Lyon, UCBL, MATEIS, UMR 5510, 69621 Villeurbanne, France Univ Lyon, UCBL, IRCELYON, UMR CNRS 5256, F-69626 Villeurbanne, France

From conventional to environmental studies of (nano)materials: the modern Transmission Electron Microscopy is a true ‘nanolab’!

Since its pioneering development in the 1930s, the Transmission Electron Microscope (TEM) has always been an invaluable instrument for the characterization of condensed matter at micrometric, nanometric and sub-nanometric scales. In the last few decades, considerable progresses have been made on many aspects to improve the TEMs performances: spatial, energetic and temporal resolutions, multi-dimensional approaches, in situ and environmental or operando methodologies.

This presentation will concentrate on the evolution of Conventional, i.e. high vacuum, to Environmental, i.e. with a non-vacuum, gas or liquid environment, TEM or so-called ETEM. Surpassing the limitations imposed by the observation of materials under vacuum, ETEM has become a new sharp blade of the TEM Swiss Army knife for studying materials at the nanoscale in almost operando conditions. Spectacular technological improvements have been made for both dedicated ETEMs and E-cells, enabling today to follow a chemical reaction under gas and in temperature down to the atomic level.

We will survey here several studies mainly conducted on the 80-300 kV FEI-TITAN ETEM installed at CLYM (www.clym.fr) in Lyon in 2013:

- TEM and STEM (Scanning TEM) High Resolution and EELS (Electron Energy-Loss spectroscopy) experiments on various materials (metallic alloys, optical ceramics) in aberration-corrected instruments under conventional high vacuum conditions

- Identification of active sites in the MoVTe oxide ‘M1’ catalyst used for ethane oxidative dehydrogenation

- In situ oxidation-reduction experiments up to 1000°C (calcination / reduction of Pd-based nanoparticles supported on delta-alumina or SiNx amorphous films, methane oxidation by ceria CeO2)

- atomic mobility at {100} surfaces of ceria linked with absorption of carbonates - kinetic 3D (i.e. ‘fast tomography’) study of soot combustion on YSZ catalysts [1].

[1] Thanks are due to colleagues for either providing samples and problematics (A.S. Gay, IFPen, Solaize, F; A. Gänzler, KIT, Karlsruhe, De; W. Zu, ORNL, USA), or contributing in different ways to the experiments (S. Koneti, L. Roiban, M. Bugnet, MATEIS, INSA-Lyon; M. Aouine, F.C. Santos Aires, E. Ehret, P. Gelin, S. Li, L. Piccolo, J.M. Millet, P. Vernoux, IRCELYON, Univ. Lyon 1, Villeurbanne; M. Duchamp, Lision, NTU Singapore; Q. Jeangros, EPFL Neuchâtel, Switzerland) or to data treatments (T. Grenier, M. Voichita, H. Banjak, CREATIS, INSA-Lyon, F; C. Ducottet, K. Faraz, L. Gramoli, LaHC, Univ. J. Monnet, St-Etienne). The support of ANR through several projects (CONTRA-PRECI, 3DCLEAN and WATEM) is gratefully acknowledged.