HERNANDEZ Olivier

University Professor

Functions :

• University Professor (Section 33 Chemistry of Materials), Chemistry Department, Faculty of Science and Technology, Nantes University
• Scientific referent for the X-ray Diffraction platform of IMN’s PLASSMAT platform

Qualifications :

• HDR in Chemistry and Chemistry-Physics (University of Rennes 1) 2012: “Contribution à l’étude des phénomènes structuraux de mise en ordre/désordre par diffusion/diffraction sur grands instruments: des composés moléculaires aux oxydes des métaux de transition” (Contribution to the study of structural ordering/disordering phenomena by scattering/diffraction on large instruments: from molecular compounds to transition metal oxides).
• Doctoral thesis in Materials Science (Université Paris VI Pierre et Marie Curie, Laboratoire Léon Brillouin, UMR 12 CEA/CNRS, CEA/Saclay) 1997: “Etude par diffusion des neutrons du chlorure de bétaïne et de calcium dihydraté sous champ externe appliqué (température, champ électrique, pression hydrostatique)”.
• DEA in Materials Science (Université Paris VI Pierre et Marie Curie) 1993
• Master’s degree in Physics (Université du Maine, Le Mans) 1992

Expertises :

• Ab initio structural resolution on powder and single crystal by XRD
• Structural, Rietveld, sequential or parametric refinements
• Study of static and dynamic disorder using the maximum entropy method (MEM) and anharmonic development of atomic displacement parameters
• TLS analysis of atomic displacement parameters
• Determination of mottled or stacking fault crystal structures
• Determining modulated incommensurate or composite incommensurate crystal structures (misfits): the superspace approach
• Pair distribution function (PDF) analysis coupled with total X-ray and neutron scattering
• Microstructural diffraction analysis
• In situ or operando diffraction
• Determination of magnetic structures by neutron diffraction
• Studies of structural or magnetic phase transitions
• Crystallochemistry of chalcogenides (including oxides) and transition metal clusters

Main research themes:

• Advanced solid-state crystallography (by X-ray, neutron and electron diffraction/diffusion): transition metal chalcogenides, polyoxometallates and organic-inorganic transition element hybrid compounds
• Chemical and electrochemical reactivity, crystallochemical, magnetic and ionic diffusion properties in oxides, mixed anion compounds and transition metal clusters
• Ordering/disordering phenomena in solids
• Advanced crystallographic approaches

Current research projects :

• Layered polychalcogenides (S. Sasaki/L. Cario, ANR COBEDIT)
• Thermoelectric sulfide misfits (D. Berthebaud/S. Jobic/L. Cario)
• Superconducting selenide misfits (L. Cario/S. Sasaki, ANR MISFIT)
• Layered oxychalcogenides with stacking faults (S. Sasaki)
• Luminescent polyoxometallates for water detection (R. Dessapt, Y. Cartigny, ANR ALPS-Water)
• AI-assisted methodology for the discovery of new materials in molten salt (R. Gautier/D. Berthebaud/D. Portehault (LCMCP), MADNESS PEPR DIADEM)
• Mechanochromic luminescence in copper iodide clusters (S. Perruchas)
• Hybrid perosvskites for thermal storage (T. Devic)
• Metal clusters and proton conducting polyoxometallates (S. Cordier (ISCR Rennes), C. Falaise (ILV Versailles), J. Cuny (LCPQ Toulouse), ANR PRESTO submitted)
• Mixed-anion Mo cluster nanoribbons (ISCR Rennes, Institut Josef Stefan, Slovenia)
• Perovskite-derived oxides for SOFC and SOEC applications: defects and diffusion paths (J. Gamon, J.-M. Bassat, ICMCB Bordeaux)
• Lacunar layered perovskites (Kyoto University: H. Kagayama & K. Fujita’s laboratories)

Activities in the research community :

• Member of the CNRS RECIPROCS network (Network of researchers and ITA professionals in structural crystallography)
• Member of the scientific committee for the Association Française de Cristallographie congress in 2026

Biography:

After my PhD thesis in Materials Science (1994-1997: Université Paris VI Pierre & Marie Curie; Laboratoire Léon Brillouin, CEA/Saclay), I spent two post-doctoral years as a contract teacher-researcher: ATER at Université Paris VI Pierre & Marie Curie in 1997-1998 (Laboratoire Léon Brillouin) then ATER at Université de Lille 1 in 1998-1999 (Laboratoire de Dynamique et Structure des Matériaux Moléculaires, UMR CNRS 8024, currently Unité Matériaux et Transformations, UMR CNRS 8207). I was appointed Maître de Conférences des Universités in Section 33 Chemistry of Materials at the University of Rennes 1 in September 1999, in the Structure and Properties of Matter Department. From 1999 to 2006, I was based at the Laboratoire de Chimie du Solide et Inorganique Moléculaire (UMR CNRS 6511), and from 2006 to August 2022 I carried out my research activities at the ISCR (UMR CNRS 6226) in the Inorganic Materials: Soft Chemistry and Reactivity and Solid Chemistry and Materials teams. In 2004-2005, a CRCT allowed me to spend 8 months in the Crystalography Laboratory at EPFL in Switzerland. In September 2022, I was recruited to the Chemistry Department of the Faculty of Science and Technology at Nantes University, within the IMN MIOPS team, following a competitive examination for the 46-1 position of University Professor (section 33 Chemistry of Materials).

Teaching :
For the Chemistry Department of the Faculty of Science and Technology of Nantes University :

• X-ray powder diffraction (M2 A3M)
• Advanced X-ray and neutron diffraction (M2 E-MAT)
• Crystallography and X-ray diffraction (M1 A3M, SdM, LUMOMAT)
• Statistical thermodynamics (L3 PC)
• Group theory (L3 PC)
• Coordination chemistry (L3 C)
• Thermochemistry (L2 C)
• Inorganic Chemistry (L1)
• Thermochemistry and equilibria in aqueous solutions (L1)

For IUT Sciences et Génie des Matériaux, Nantes Université:
Diffraction techniques (BUT3)

For the University of Rennes:
Crystallography (International Master 1 in Chemistry-M1 LUMOMAT)

IMN Level 1 short continuing education course (1 week) “Diffraction in polycrystalline materials”:
X-ray powder diffraction, Symmetry in crystals, Microstructure (external standard and fundamental parameters), Phase quantification

Publications :

Number of publications: 85

Major illustrative publications:

Mechanoresponsive luminescence triggered by phase transition of a supercooled copper(I) complex J. Delafoulhouze, M. Cordier, J.-Y. Mevellec, F. Massuyeau, O. Hernandez, C. Latouche, S. Perruchas CHEMICAL COMMUNICATIONS 60, 5278-5281 (2024)

Exsolution of Co-Fe alloy nanoparticles on the PrBaFeCoO5+ layered perovskite monitored by neutron powder diffraction and catalytic effect on dry reforming of methane P. Managutti, H. Yu, O. J. Hernandez, C. Prestipino, V. Dorcet, H. Wang, T. C. Hansen, M. Bahout ACS APPLIED MATERIALS & INTERFACES 15 (19), 23040-23050 (2023)

Mechanochemical Synthesis and Study of the Local Structure of NaGaS2 Glass and Glass-Ceramics L. Verger, J. Trébosc, B. Baptiste, E. Furet, K. Dénoue, J. Zhang, F. Cheviré, D. Le Coq, L. Calvez, O. Lafon, O. Hernandez INORGANIC CHEMISTRY 61, 46, 18476-18485 (2022)

In Situ Synchrotron Powder Diffraction Study of Cd Intercalation into Chevrel Phases: Crystal Structure and Kinetic Effect J. Barbosa, C. Prestipino, O. J. Hernandez, S. Paofai, C. Dejoie, M. Guilloux-Viry, C. Boulanger INORGANIC CHEMISTRY 58, 3, 2158-2168 (2019)

‘Hybrid Improper Ferroelectricity in (Sr,Ca)3Sn2O7 and Beyond: Universal Relationship between Ferroelectric Transition Temperature and Tolerance Factor in n = 2 Ruddlesden-Popper Phases
S. Yoshida, H. Akamatsu, R. Tsuji, O. Hernandez, H. Padmanabhan, A. Sen Gupta, A. S. Gibbs, K. Mibu, S. Murai, J. M. Rondinelli, V. Gopalan, K. Tanaka, K. Fujita JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 140, 15690-15700 (2018)

Site Selectivity of Hydride in Early-Transition-Metal Ruddlesden-Popper Oxyhydrides O. J. Hernandez, G. Geneste, T. Yajima, Y. Kobayashi, M. Okura, K. Aidzu, C. Tassel, S. Paofai, D. Swain, C. Ritter, H. Kageyama INORGANIC CHEMISTRY 57, 11058-11067 (2018)

Structure and reactivity with oxygen of Pr2NiO4+δ: an in situ synchrotron X-ray powder diffraction study T. Broux, C. Prestipino, M. Bahout, S. Paofai, E. Elkaïm, V. Vibhu, J.-C. Grenier, A. Rougier, J.- M. Bassat, O. Hernandez DALTON TRANSACTIONS 45, 3024-3033 (2016)

Hydride in BaTiO2.5H0.5: A Labile Ligand in Solid State Chemistry N. Masuda, Y. Kobayashi, O. Hernandez, T. Bataille, S. Paofai, H. Suzuki,C. Ritter, N. Ichijo, Y. Noda, K. Takegoshi, C. Tassel, T. Yamamoto, H. Kageyama JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 137, 15315-15321 (2015)

Oxygen diffusion mechanism in the mixed ion-electron conductor NdBaCo2O5+x Y Hu, O. Hernandez, T. Broux, M. Bahout, J. Hermet, A. Ottochian, C. Ritter, G. Geneste, G. Dezanneau
JOURNAL OF MATERIALS CHEMISTRY 22, 36, 18744-18747 (2012)

An oxyhydride of BaTiO3 exhibiting hydride exchange and electronic conductivity Y. Kobayashi, O.J. Hernandez, T. Sakaguchi, T. Yajima, T. Roisnel, Y. Tsujimoto, M. Morita, Y. Noda, Y. Mogami, A. Kitada, M. Ohkura, S. Hosokawa, Z.F. Li, K. Hayashi, Y. Kusano, J.E. Kim, N. Tsuji, A. Fujiwara, Y. Matsushita, K. Yoshimura, K. Takegoshi, M. Inoue, M. Takano, H. Kageyama NATURE MATERIALS 11, 6, 507-511 (2012)

Tetrahedral Mo4 Clusters as Building Blocks for the Design of Clathrate-Related Giant Frameworks M.A. Shestopalov, A.Y. Ledneva, S. Cordier, O. Hernandez, M. Potel, T. Roisnel, N.G. Naumov, C. Perrin ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 50, 32, 7300-7303 (2011)

Patent :

1 submitted (“Matériau à changement de phase solide solide pour la thermalisation et le stockage thermique”, C. Archinard, E. Djanffar, T. Devic, O. Hernandez, A. Saad, E. Zekri, G. Largiller, DV 5547 Réf. SATT Ouest Valorisation, DD25114 Réf. CEA)