Focus MET Environmental

nationalInternational audienc

Apport de la microscopie électronique en transmission à l'étude de catalyseurs

nationalInternational audienc

Influence of the crystalline phase of the support on the deactivation of Pd supported catalysts in the total oxidation of methane

internationa

Synthesis and physico-chemical characteristics of nanosized particles produced by laser ablation of a nickel target in water

International audienceAblation of Ni targets in water by laser impact (532 nm, 40 mJ/pulse, 10 Hz and 8 ns duration) focused on massive samples (about 2 mm diameter) generates colloids with fine nanoparticles. The amount of metal released in the solution (measured by mass loss of the target or ICP) was found to increase first linearly with time, but slower after 8 min of impact. The size distribution of the nanoparticles thus produced was measured (by TEM) to be in the range 3–5.3 nm in diameter, with a tendency for the size to be smaller for larger number of laser shots. Actually, nickel oxide nanoparticles were produced, rather than nickel nanoparticles as it was shown by HRTEM. XPS photoemission measurements evidenced the presence of nickel oxide species on the crater of the nickel sample surface after laser ablation

Investigating the evolution of catalytic surfaces under realistic conditions: CO adsorption on Au(110).

internationa

A High Pressure PM-IRRAS Study of CO and O2 Coadsorption and Reactivity on PtSn Alloy Surfaces

International audienceThe adsorption of CO on the two terminations, p(2 × 2) and (√3 × √3) R30°, of the bulk Pt3Sn(111) alloy is studied by high pressure polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS). The influence of O2 is also investigated. While no differences are observed when CO is chemisorbed alone, the behavior of the two terminations clearly differs in presence of O2. The presence of oxygen induces modifications on the (√3 × √3)R30° surface. Finally we study how the interaction between O2 and the surface modifies the reactivity. Hence we show that the p(2 × 2) termination is more efficient than the (√3 × √3) R30° for CO oxidation. However this termination remains more efficient than pure platinum

Bimetallic Pd-Sn and Pd-Ga Catalysts for the Hydrogenation of 1,3-Butadiene

Internationa

AlMCM-41: synthesis, characterization and catalytic behaviour

internationa

Pd and Ag catalysts supported on Si3N4 for the total and partial oxidation of hydrocarbons

internationa