Au-Rh and Au-Pd Nanoalloys supported on well-defined Rutile Titania Nanorods for Aromatics Hydrogenation Applications - Archive ouverte HAL Accéder directement au contenu
Communication Dans Un Congrès Année : 2013

Au-Rh and Au-Pd Nanoalloys supported on well-defined Rutile Titania Nanorods for Aromatics Hydrogenation Applications

Z. Konuspayeva
  • Fonction : Auteur
G. Berhault
P. Afanasiev
T.S. Nguyen
  • Fonction : Auteur
A. Auyezov
  • Fonction : Auteur
M. Burkitbayev
  • Fonction : Auteur
L. Piccolo

Résumé

Tuning the composition of bimetallic catalysts as well as controlling their interaction with oxide supports are critical in order to control catalytic properties for hydrogenation and oxidation reactions. In this respect, a tremendous work has been made in recent years to prepare Au-based bimetallic catalysts due to the enhancement of catalytic properties when combining Au with noble metals in nanoalloys [1]. However, up to now, while Au-Pd systems have been widely studied mainly for oxidation reactions, Au-Rh nanoalloys have been rarely envisaged [2, 3]. Similarly, the nature of the interaction between these bimetallic systems and oxide supports is not well understood due to the poorly defined morphology of most of the oxides used. Therefore, using well-defined oxide supports offers opportunities to simplify the nature of the bimetallic particles – support interaction. The objective of the present study was to prepare Au-M (M = Rh, Pd) bimetallic systems by comparing the efficiency of colloidal or impregnation techniques for obtaining nanoalloys with fine tuning of their composition. These Au-M bimetallic systems were supported on TiO2 nanorods to provide catalytic systems with well-defined metal-support interaction for in-depth HRTEM characterization. Rutile nanorods were obtained first by peptization under acidic conditions using HClO4 and hydrous titania as precursor. Second, a hydrothermal treatment was performed at 200°C for 48 h under strong acidic conditions (pH = 0.8) in the presence of a shape controlling agent, MgSO4, in order to obtain rods. Results clearly demonstrate the superiority of colloidal techniques, particularly for the Au-Rh case, in comparison to impregnation of the different metallic salts followed by reduction. While impregnation leads to the formation of a high proportion of Au or Rh monometallic particles, precise tuning of colloidal preparation conditions led to Au-Rh nanoalloys with controlled composition. Optimization of colloidal conditions was however found to be critical to avoid redissolution of Rh during preparation and formation of isolated Rh raft-like particles. Similar conditions were obtained for the Au-Pd bimetallic systems. Characterization by HRTEM, XPS, and EDX was performed after deposition on TiO2 nanorods. Finally, in the context of fuel upgrading, the catalysts have been evaluated in benzene hydrogenation in the presence of toluene and tetralin hydroconversion, both at high hydrogen pressure (4 MPa). In this contribution, the effect of gold addition on the hydrotreating and th ioresistance properties of rhodium will be presented and discussed on the basis of in-depth structural characterization. [1] D. Uzio, G. Berhault, Catal. Rev. 52 (2010) 106-131. [2] E.R. Essinger-Hileman, D. DeCicco, J.F. Bondi, R.E. Schaak, J. Mater. Chem. 21 (2011) 11599-11604 [3] Á. Kukovecz, G. Potari, A. Oszko, Z. Konya, A. Erdohelyi, J. Kiss, Surf. Sci. 605 (2011) 1048-1055.
Fichier non déposé

Dates et versions

hal-00916066 , version 1 (09-12-2013)

Identifiants

  • HAL Id : hal-00916066 , version 1

Citer

Z. Konuspayeva, G. Berhault, P. Afanasiev, T.S. Nguyen, A. Auyezov, et al.. Au-Rh and Au-Pd Nanoalloys supported on well-defined Rutile Titania Nanorods for Aromatics Hydrogenation Applications. 2013 Materials Research Society fall meeting, Dec 2013, Boston, United States. ⟨hal-00916066⟩
156 Consultations
0 Téléchargements

Partager

Gmail Facebook X LinkedIn More