In situ spectroscopic detection of SMSI effect in a Ni/CeO2 system: hydrogen-induced burial and dig out of metallic nickel.

In situ APPES technique demonstrates that the strong metal support interaction effect (SMSI) in the Ni-ceria system is associated with the decoration and burial of metallic particles by the partially reduced support, a phenomenon reversible by evacuation at high temperature of the previously absorbed hydrogen.

Influence of the cobalt particle size in the CO hydrogenation reaction studied by in situ X-ray absorption spectroscopy.

The influence of particle size in the carbon monoxide hydrogenation reaction has been studied using cobalt nanoparticles (NPs) with narrow size distribution prepared from colloidal chemistry. The surfactant covering the NPs after synthesis could be removed by heating to 200-270 degrees C in H(2). Soft X-ray absorption spectroscopy was performed using a gas flow cell under reaction conditions of H(2) and CO at atmospheric pressure.

Surface chemistry of Cu in the presence of CO2 and H2O.

The chemical nature of copper and copper oxide (Cu 2O) surfaces in the presence of CO 2 and H 2O at room temperature was investigated using ambient pressure X-ray photoelectron spectroscopy. The studies reveal that in the presence of 0.1 torr CO 2 several species form on the initially clean Cu, including carbonate CO 3 (2) (-), CO 2 (delta-) and C (0), while no modifications occur on an oxidized surface.

Silylation of a Co/SiO2 catalyst. Characterization and exploitation of the CO hydrogenation reaction.

Several silylated- and nonsilylated Co/SiO2 catalysts have been prepared by reaction of the surface silanol groups with hexamethyldisilazane (HMDS). These samples have been characterized by means of N2 adsorption isotherms, solid-state nuclear magnetic resonance (29Si and 1H), X-ray photoelectron spectroscopy, thermogravimetric analysis, and diffuse reflectance IR spectroscopy. We have focused on the study of the silylated surface stability at high temperatures and in different atmospheres.