New reactor dedicated to in operando studies of model catalysts by means of surface x-ray diffraction and grazing incidence small angle x-ray scattering

International audienceA new experimental setup has been developed to enable in situ studies of catalyst surfaces during chemical reactions by means of surface x-ray diffraction (SXRD) and grazing incidence small angle x-ray scattering. The x-ray reactor chamber was designed for both ultrahigh-vacuum (UHV) and reactive gas environments. A laser beam heating of the sample was implemented; the sample temperature reaches 1100 K in UHV and 600 K in the presence of reactive gases. The reactor equipment allows dynamical observations of the surface with various, perfectly mixed gases at controlled partial pressures. It can run in two modes: as a bath reactor in the pressure range of 1-1000 mbars and as a continuous flow cell for pressure lower than 10−3 mbar. The reactor is connected to an UHV preparation chamber also equipped with low energy electron diffraction and Auger spectroscopy. This setup is thus perfectly well suited to extend in situ studies to more complex surfaces, such as epitaxial films or supported nanoparticles. It offers the possibility to follow the chemically induced changes of the morphology, the structure, the composition, and growth processes of the model catalyst surface during exposure to reactive gases. As an example the Pd8Ni92(110) surface structure was followed by SXRD under a few millibars of hydrogen and during butadiene hydrogenation while the reaction was monitored by quadrupole mass spectrometry. This experiment evidenced the great sensitivity of the diffracted intensity to the subtle interaction between the surface atoms and the gas molecules

Les unités motrices en agriculture

Perroux François. Les unités motrices en agriculture. In: Économie rurale. N°78, 1968. Les nouveaux facteurs de localisation de la production agricole dans la C. E. E. pp. 5-12

Les pôles de développement et la politique de l'Est

Perroux François. Les pôles de développement et la politique de l'Est. In: Politique étrangère, n°3 - 1957 - 22ᵉannée. pp. 233-270

Note sur les énoncés successifs de la fonction de production

Perroux François. Note sur les énoncés successifs de la fonction de production. In: Tiers-Monde, tome 8, n°31, 1967. pp. 679-684

Préface

Perroux François. Préface. In: Tiers-Monde, tome 8, n°32, 1967. L'Espagne à l'heure du développement. pp. 807-811

Les techniques quantitatives de la planification

307 p., fig