Picture of Thierry Epicier

Thierry Epicier


Orcid number: 0000-0001-5552-1418

445 300 (Switchboard + 33 [0] 472 445 300)


Methodology in Environmental Microscopy (MEME)


Transmission Electron Microscopy (TEM), Environmental TEM (ETEM), relationships between structures, nano- microstructures of materials and their functional properties, nanaoparticles, heterogeneous catalysis



  • 1983-1988 French 'Doctorat d’Etat', INSA-Lyon, Villeurbanne, F.
  • 1980-1982 PhD in Materials Science, Université Claude Bernard Lyon I - INSA de Lyon - ECL, Lyon-Villeurbanne-Ecully, F.
  • 1980 DEA ‘Sciences des Matériaux et des Surfaces’, Université Claude Bernard Lyon I - INSA de Lyon - ECL, Lyon-Villeurbanne-Ecully, F.
  • 1977-1980 Engineer Ecole Centrale de Lyon, F. 
  • 1975-1977 Classes préparatoires, Lycée B. Pascal, Clermont-Fd , F. 



  • 2020-: Head of the 'MEME' group: Methodologies in Environmental Microscopy Studies at IRCELYON


  • 2020-2023: coordinator of the ANR project 20-CE42-0008 'WATEM' : WAter in a TEM (IRCELYON, MATEIS - INSA de Lyon, LISION/Majulab, NTU Singapor)
  • 2020/04 (changing lab.): CNRS Research Director at IRCELYON, umr CNRS 5256, Université Claude Bernard Lyon 1 (UCBL), Villeurbanne, France
  • 2020: organisator of the SEEN workshop: Solutions for Environmental Electron Nanoscopy (Milexia / DENSsolutions / MATEIS / IRCELYON, Lyon,F).
  • 2018-2019: President of the Scientific ANR committee 42  (https://anr.fr/), AAPG 2019.
  • 2018: Member of the International Advisory Board of the XIX° International Microscopy Congress IMC2018 (imc19.com, Sept. 9-14 2018, Sidney, Australia).
  • 2017-2018: President of the Scientific ANR committee 42  (https://anr.fr/), AAPG 2018.
  • 2017: Member of the Scientific Committee for the ‘Advanced Multiscale Microstructural Studies’ symposium at the SF2M Conference (Soc. Française de Métallurgie et de Matériaux), Oct. 23-25, Lyon, F.
  • 2016: Co-organisator of the GLEEM workshop: Gas and Liquid Environmental Electron Microscopy, CNRS – Michel Ange, 13-14 Dec. 13/14 2016, Paris, F.


  • 2016-2020: Deputy-Director of the French CNRS Federation ‘METSA’: Microscopie Electronique en Transmission et Sonde Atomique, FR CNRS 3507, F.
  • 2016: Chair/President of the XVIth European Microscopy Congress EMC2016, 28/08 - 02/09 2016, Lyon, F.


  • 2015-2019: Coordinator of the ANR projet 3DCLEAN (3D Catalytic Environmental Lab at the Nanoscale).
  • 2013: Chair of the IWETEM workshop: International Workshop on Environmental Transmission Electron Microscopy, Lyon, France, 2013/11/26 (see EMS Year Book 2014).
  • 2013-14: CNRS Research Director, temporary position at IRCELYON, umr CNRS 5256, Université Claude Bernard Lyon I, Villeurbanne, F.
  • 2016-2020: Deputy-Director of the French CNRS Federation ‘METSA’: Microscopie Electronique en Transmission et Sonde Atomique, FR CNRS 3507, F.
  • 2003-2020/03: CNRS Research Director at MATEIS (former GEMMPM before 2007), umr CNRS 5510, INSA de Lyon, Villeurbanne, France
  • 2001: Chargé de recherches CNRS, temporafry position at LTDS, umr CNRS 5513, Ecole Centrale de Lyon, Ecully, F.
  • 1988-89: post-doctoral stay at National Center for Electron Microscopy (NCEM), LBNL, University of Berkeley, CA, USA.
  • 1983-2003: Chargé de recherches CNRS, GEMPPM, umr CNRS 341, INSA de Lyon, Villeurbanne, F.



Since my arrival in IRCELYON, my research is more focussed on Environmental TEM to study the evolution of nanocatalysts during in situ conditions approaching operando working conditions. It aims at characterizing and understanding the evolution of nanocatalysts during in situ and/or operando gas and temperature experiments.

Reduction of Au0.2Pd0.8 nanoparticles from micellar networks during in situ CO oxidation in ETEM. Left: tretament under oxygen showing the generation of core-shell and Janus Pd@Au configurations (centre). Right: fast reduction under CO. The inset shows the RGA measurement of gases (without correction the time delay)). METSA experiment, B. Dominicini (ICB, Dijon), F.C. Santos Aires, E. Ehret, L. Burel, T. Epicier, (2021).


These studies include the reproduction of conditions relative to the conditionning of catalysts, calincation or reduction, 
which allow to identify elementary mechanisms leading to deactivation or loss of performances of the catalysts (i.e. poisonning, coking, growth or transformation of nanoparticles)  .

In situ ETEM calcination of supported Pd(O) nanoparticles on delta-alumina, showing the decrease in number and the increase in size of the nanoparticle population, due to Ostwald Ripening (T. EPICIER et al., Catalysis Today 334 (2019) 68).


Une activité spécifique concerne une double approche d’Apprentissage Profond (réseau de neurones) et de Vision par Ordinateur (suivi d’objets multiples) permettant de quantifier l’’évolution dynamique d’une population de nanoparticules lors d’expériences ETEM in situ. Elle consiste en l’entrainement d’un réseau Unet sur des simulations réalistes d’images STEM de nanoparticules supportées et en la reconstruction de leurs trajectoires en fonction du temps grâce à un algorithme dédié basé sur des critères d’énergie continue.

Example of simulations of a ground truth referring to experimental supported PdO Nanoparticles on a delta-alumina support during calcination under oxygen). Left: starting microstructure showing the automatic identification of nanoparticles (yellow circles). Right: nanoparticle trajectories (in progress: in blue, stopped – disappearance or fusion/coalescence as shown by green arrows -: in red). Joined project MATEIS/IRCELYON, LaHC and CREATIS).


Another specific activity is linked to the opportunity to easily observe solid/vapor interfaces in a dedicated ETEM (as for a dedicated ESEM), owing to the absence of sealing membranes as when using an environmental cell in a conventional, high vacuum microscope. The WATEM ANR project (2020-2023) aims at analyzing in situ under wet conditions both deliquescence and efflorescence of synthetic and/or natural aerosols in the context of fine studies of cloud formation elementary mechanisms.


Deliquescence of NaCl nanocubes in a wet atmosphere in the ETEM. The progressive decrease of temperature as well as the increase of the water vapor partial pressure in the microscope vacuum leads to the dissolution of the salt phase. The experience has been conducted under controlled irradiation conditions : maximal electron flux (indicated for each condition in blue) equal to 4 e -.A-2.s-1 during 300 s, received electron dose (in blue) about 300 e-.A-2, much less than a ‘proof test’ at 3000 e-.A-2 (WATEM project, F.C. Santos Aires, E. Ehret, C. Chatre, T. Epicier, IRCELYON ; L. Roiban, MATEIS).

I am involved in Transmission Electron Microscopy since more than 20 years and have a general experience in Electron Microscopy, as attested by the various domains covered by its scientific production:


Conventional TEM applied to dislocations analysis and plasticity elementary mechanisms

Study of long-range order phenomena

High Resolution imaging (grain-boundary structures in ceramics, nano-particles, precipitation in alloys, image simulation

development of computer programs: e.g. PC adaptation of the ‘SHRLI’ set of simulation programs from M.A. O'Keefe ; Diffraction-Workshop : freeware for indexing diffraction patterns

Analytical TEM: EDX and EELS for quantitative elemental analysis (carbon and or nitrogen in sub-stoichiometric metallic carbo-nitrides) or valence and chemical bond analysis (ELNES, FEFF simulations, anisotropic effects - trichroïsm -)

High Angle Annular Dark Field imaging (conventional and at atomic resolution), Cs-corrected HREM (and HAADF), electron tomography

SEM (STEM mode, tomography), FIB and 3D ‘slice-and-view’ imaging or EBSD analysis

Environmental TEM in the context of heterogeneous catalysis (since 2013)

All these studies were declined to different classes of materials: metallic alloys (including steels), ceramics, nano-particles (core-shell structures, bi-metallic phases for magnetic applications, hybrid nano-materials, nanowires, catalysts), polymers and various kinds of heterogeneous and composite materials.


Since my arrival in IRCELYON, my research is more focused on Environmental TEM to study the evolution of nanocatalysts during in situ conditions approaching operando working conditions.



  • 2020- : Contribution to a "Advanced Manufacturing and Materials Science" (AM2S) Master2 course ; Arts et Métiers (Aix-en-Provence, F) and Texas A&M University.
  • 2015 : Course on Electron Tomography at the International Electron Microscopy School, Fès, Marocco, 2014-04-12). 
  • 2012-2018 : Teachder in training sessions ‘MET appliquée à la science des matériaux – 1 er 2’, Villeurbanne, and ‘La tomographie électronique : théorie et pratique’, Strasbourg (CNRS-Formation labels)
  • 2008 : Course on Microscopies Électroniques et Transformations de phases avec diffusion dans les solides, French School CNRS "TRansDiff", Porquerolles, F).
  • 2005-2013 : Responsible of the training session ‘Microscopie Electronique en Transmission en Sciences des Matériaux : Pratique Approfondie et Dépouillement Informatique’, Villeurbanne (CNRS-Formation label)
  • 2001 : course on Electron Diffraction and HRTEM at the SFµ French School: Microscopie des Défauts Cristallins’, St Pierre d’Oléron, (2001), ed. Soc. Française des Microscopies.
  • 1997-2016 : Responsible of the 'Microscopies des Matériaux' Master2 course (Doctoral School ED34, Univ. de Lyon)
  • 1994 : course on "Practical simulation of HRTEM images" at the 'NCEM 1994 Summer School on Image Simulation & Processing', Lawrence Berkeley Lab., Berkeley, CA, USA.