• Article dans une revue

Contribution to the understanding of the formation mechanism of bimodal mesoporous MCM41-type silica with large defect cavities

Claudia Bernal, Monica Mesa, Maguy Jaber, Jean-Louis Guth, Ligia Sierra

The formation mechanism of large defect cavities (∅ 11-23 nm) beside the MCM41 mesopores (∅ ∼ 2.3 nm), was studied from mixtures of sodium silicate, cetyl trimethyl ammonium bromide (CTAB) and ethyl acetate (EtAc) with the molar composition 1 SiO2; 1 Na2O; x CTAB; y EtAc: 237 H2O (with x = 0.33 or…

Microporous and Mesoporous Materials, 2011, 153, pp.217-226. ⟨10.1016/j.micromeso.2011.12.049⟩. ⟨hal-00688611⟩

• Article dans une revue

Formation of heteropolymolybdates during the preparation of Mo and NiMo HDS catalysts supported on SBA-15: Influence on the dispersion of the active phase and on the HDS activity

Alvaro Sampieri, Stephane Pronier, Sylvette Brunet, Xavier Carrier, Catherine Louis, Juliette Blanchard, Katia Fajerwerg, Michele Breysse

Mo and Ni-Mo sulfides in SBA-15 and Al-SBA-15 catalysts were prepd. by incipient wetness co-impregnation of molybdenum and nickel precursors (followed by thermal treatment under He at 823 K) and sulfidation under 10% H2S/H2 at 673 K. Only incipient wetness impregnation of Mo on pure silica SBA-15…

Microporous and Mesoporous Materials, 2010, 130 (1-3), pp.130-141. ⟨10.1016/j.micromeso.2009.10.024⟩. ⟨hal-00604795⟩

• Article dans une revue

Comparison of competition between T = O and T-OH groups in vanadium, niobium, tantalum BEA zeolite and SOD based zeolites

Anna Wojtszek, Maria Zioleck, Stanislaw Dzwigaj, Frederik Tielens

The investigation of intra framework substitution of Si by group V transition metals (V, Nb, Ta) is an important strategy to modify or to tune the catalytic properties of zeolites. Theoretically one of the limitations is the size of the zeolite unit cell. In this study the energy and geometry of…

Chemical Physics Letters, 2011, 514, pp.70-73. ⟨10.1016/j.cplett.2011.08.005⟩. ⟨hal-00666258⟩

• Article dans une revue

Selective Modification of the Acid-Base Properties of Ceria by Supported Au

Manuela C.I. Bezen, Cornelia Breitkopf, Nadia El Kolli, Jean-Marc Krafft, Catherine Louis, J.A. Lercher

Au supported on CeO2 prepared by deposition-precipitation with urea leads to a basic catalyst. Au acts in two ways as surface modifier. First, Au selectively interacts with Ce4+ cations by either blocking access to or reducing Ce4+ to Ce3+. Second, the resulting Au atoms (presumably as Au+ ions)…

Chemistry - A European Journal, 2011, 17 (25), pp.7095-7104. ⟨10.1002/chem.201002011⟩. ⟨hal-00666903⟩

• Article dans une revue

Influence of the pretreatment conditions on the performances of CeO2-supported gold catalysts in the Catalytic Wet Air Oxidation of carboxylic acids

Ngoc D. Tran, Michèle Besson, Claude Descorme, Katia Fajerwerg, Catherine Louis

Two series of ceria-supported gold catalysts (1 and 4 wt.% Au) were prepared by deposition-precipitation with urea. Depending on the gold loading, the pretreatment of the Au/CeO2 catalysts (calcination in air vs. reduction in hydrogen) had a great influence on the oxidation state of gold, and in…

Catalysis Communications, 2011, 16, pp.98-102. ⟨10.1016/j.catcom.2011.09.014⟩. ⟨hal-00666922⟩

• Article dans une revue

DFT study of the M segregation on MAu alloys (M = Ni, Pd, Pt) in presence of adsorbed oxygen O and O2

Adnene Dhouib, Hazar Guesmi

Segregation phenomena of group 10 (M = Ni, Pd, Pt) transition-metals substituted in Au (1 1 1) surface and sub-surface layers are investigated by DFT periodic calculations in presence of adsorbed atomic and molecular oxygen. In contrast with vacuum conditions, where the metal impurities M prefer to…

Chemical Physics Letters, 2011, 521, pp.98-103. ⟨10.1016/j.cplett.2011.11.050⟩. ⟨hal-00690803⟩

• Article dans une revue

Unravelling the enhanced reactivity of bulk CeO2 doped with gallium: A periodic DFT study

Paola Quaino, Olga Syzgantseva, Luca Siffert, Frederik Tielens, Christian Minot, Monica Calatayud

Doping CeO2 with gallium leads to promising materials with application in hydrogen purification processes for fuel cells. The bulk ceria-gallia is investigated by ab initio calculations. The outstanding reactivity is explained by important relaxations induced by gallium in the ceria host, having a…

Chemical Physics Letters, 2011, 519-520, pp.69-72. ⟨10.1016/j.cplett.2011.11.022⟩. ⟨hal-00690790⟩

• Article dans une revue

Dispersion and hydrogenation activity of surfactant-stabilized Rh(0) nanoparticles prepared on different mesoporous supports

Maya Boutros, Guillaume Shirley, Thomas Onfroy, Franck Launay

Supported Rh(0) colloidal particles were prepared by the reduction of Rh(III) ions by sodium borohydride in the presence of N-N-dimethyl-N-cetyl-N-(2-hydroxyethyl) ammonium chloride (HEA16Cl), usually used as a stabilizing agent in solution. Tested supports were Na-Al-SBA-15, SBA-15 and CMK-3. In…

Applied Catalysis A : General, 2011, 394 (1-2), pp.158-165. ⟨10.1016/j.apcata.2010.12.035⟩. ⟨hal-00602935⟩

• Article dans une revue

Incorporation of Nb(V) into BEA zeolite investigated by XRD, NMR, IR, DR UV-vis, and XPS

Stanislaw Dzwigaj, Yannick Millot, Christophe Methivier, Michel Che

Nb(x)SiBEA (x = 1.0, 1.5 Nb wt%) zeolites are prepared by a two-step postsynthesis method involving first the creation of vacant T-atom sites associated with silanol groups by dealumination of BEA zeolite by nitric acid solution and then by impregnation of the resulting SiBEA zeolite with the…

Microporous and Mesoporous Materials, 2010, 130 (1-3), pp.162-166. ⟨10.1016/j.micromeso.2009.10.027⟩. ⟨hal-00604714⟩

• Article dans une revue

Enhancement of the Photoinduced Oxidation Activity of a Ruthenium(II) Complex Anchored on Silica-Coated Silver Nanoparticles by Localized Surface Plasmon Resonance

Kohsuke Mori, Masayoshi Kawashima, Michel Che, Hiromi Yamashita

Angewandte Chemie International Edition, 2010, 49 (46), pp.8598-8601. ⟨10.1002/anie.201004942⟩. ⟨hal-00604784⟩