Accueil > Recherche > Microscopie Electronique Avancée et Nano-Structures (MEANS) > Thèmes de recherche

Understanding the catalytic properties of nanoalloys

publié le , mis à jour le

Heterogeneous catalysis covers nowadays a wide range of industrial processes such as selective hydrogenation in petrochemistry, pollution control and chemical synthesis. It has always used nanoparticles in order to maximize the surface/volume ratio of active particles. Among the various heterogeneous catalysts developed, bimetallic nanoparticles supported on oxides have enjoyed an overwhelming interest. Indeed, they present improved catalytic performances such as increased selectivity, activity or resistance to poisoning. The “alloying effect”, promotion of the catalytic properties of one metal by addition of a second component and the structure-activity relationships are often explained on the basis of their electronic structure and/or geometric properties. However, the potential of bimetallic catalysts is not fully used because a full knowledge of theses properties is still lacking. The poor knowledge of the active catalytic phase results from (i) the difficulty to elaborate homogeneous collections of multimetallic nanoparticles with imposed composition and (ii) the lack of structural characterization down to the atomic scale. As many structural effects control (and are controlled by) the catalytic process, precise knowledge of structure-activity relationships is of paramount importance in order to be able to rationally design new and more efficient catalysts. This demands efforts both in the synthesis and in characterization of multimetallic nanoparticles.

Our present activities on structure-activity relationships in heterogeneous catalysis concern Pd-Au, Au-Cu and Pd-Ir nanoalloys supported on TiO2/MgO. We are involved both in particle synthesis and characterization studies. Nanoparticles are synthesized by pulsed laser deposition method which offers a flexible and precise route for the synthesis of a wide variety of multimetallic nanoalloys with controllable size, structure and composition as exemplified on L10-type CoPt nanoparticles. The central characterization technique to study the structural properties (atomic arrangement, composition, morphology, size) of the supported nanoalloys will be the last-generation of aberration-corrected transmission electron microscopy. It will involve the implementation and development of (S)TEM imaging and spectroscopic techniques like UHRTEM, tomography, EELS and EDX on the aberration-corrected ARM200 microscope due to arrive in September 2010. More precisely, these studies will enable us to gain fundamental knowledge on the atomic/chemical structure of the nanoalloys and on their interface with the oxide supports. These activities are done in collaboration with Laurent Piccolo of IRCELYON-Lyon and Florence Epron of LACCO-Poitiers.

Collaborators :

ANR Project : DINAMIC

  • {{}} Institute of Researches on Catalysis and Environment of Lyon (IRCELYON) : L. Piccolo
  • {{}} Laboratory of Catalysis in Organic Chemistry (LACCO, Univ. Poitiers / CNRS) : F. Epron

Publication :

Selective hydrogenation of butadiene over TiO2 supported copper, gold and gold–copper catalysts prepared by deposition–precipitation
Laurent Delannoy, Gode Thrimurthulu, Padigapati S Reddy, Christophe Méthivier, Jaysen Nelayah, Benjaram M Reddy, Christian Ricolleau, Catherine Louis
Phys. Chem. Chem. Phys. 16 (48), 26514-26527

Long-range chemical orders in Au–Pd nanoparticles revealed by aberration-corrected electron microscopy
J Nelayah, NT Nguyen, D Alloyeau, GY Wang, C Ricolleau
Nanoscale 6 (17), 10423-10430

Nanoalloying bulk-immiscible iridium and palladium inhibits hydride formation and promotes catalytic performances
C Zlotea, F Morfin, TS Nguyen, NT Nguyen, J Nelayah, C Ricolleau, M Latroche, L Piccolo
Nanoscale 6 (17), 9955-9959

Au–Rh and Au–Pd nanocatalysts supported on rutile titania nanorods : structure and chemical stability
Zere Konuspayeva, Pavel Afanasiev, Thanh-Son Nguyen, Luca Di Felice, Franck Morfin, Nhat-Tai Nguyen, Jaysen Nelayah, Christian Ricolleau, Z. Y. Li, Jun Yuan, Gilles Berhault and Laurent Piccolo
Phys. Chem. Chem. Phys., 2015, Advance Article
DOI : 10.1039/C5CP00249D

New insights into the mixing of gold and copper in a nanoparticle from a structural study of Au–Cu nanoalloys synthesized via a wet chemistry method and pulsed laser deposition
Hélène Prunier, Jaysen Nelayah, Christian Ricolleau, Guillaume Wang, Sophie Nowak, Anne-Félicie Lamic-Humblot and Damien Alloyeau
Phys. Chem. Chem. Phys., 2015, Advance Article
DOI : 10.1039/C5CP01491C