Origin of the Activity Trend in the Oxidative Dehydrogenation of Ethanol over VO /CeO.

Supported vanadia (VO ) is a versatile catalyst for various redox processes where ceria-supported VO have shown to be particularly active in the oxidative dehydrogenation (ODH) of alcohols. In this work, we clarify the origin of the volcano-shaped ethanol ODH activity trend for VO /CeO catalysts using operando quick V K- and Ce L - edge XAS experiments performed under transient conditions. We quantitatively demonstrate that both vanadium and cerium are synergistically involved in alcohol ODH.

Beware of beam damage under reaction conditions: X-ray induced photochemical reduction of supported VO catalysts during XAS experiments.

X-ray absorption spectroscopy (XAS) is a powerful technique for the investigation of heterogeneous catalysts and electrocatalysts. The obtained XAS spectra are usually interpreted from the point of view of the investigated chemical processes, thereby sometimes omitting the fact that intense X-ray irradiation may induce additional transformations in metal speciation and, thus, in the corresponding XAS spectra. In this work, we report on X-ray induced photochemical reduction of vanadium in supported vanadia (VO) catalysts under reaction conditions, detected at a synchrotron beamline.

Redox Dynamics of Active VO Sites Promoted by TiO during Oxidative Dehydrogenation of Ethanol Detected by Quick XAS.

Titania-supported vanadia (VO /TiO) catalysts exhibit outstanding catalytic in a number of selective oxidation and reduction processes. In spite of numerous investigations, the nature of redox transformations of vanadium and titanium involved in various catalytic processes remains difficult to detect and correlate to the rate of products formation. In this work, we studied the redox dynamics of active sites in a bilayered 5% VO/15% TiO/SiO catalyst (consisting of submonolayer VO species anchored onto a TiO monolayer, which in turn is supported on SiO) during the oxidative dehydrogenation of ethanol.

Mechanism of Zr Incorporation in the Course of Hydrothermal Synthesis of Zeolite BEA.

The mechanism of Zr-BEA hydrothermal synthesis in fluoride media has been investigated through the detailed characterization of samples obtained at different synthesis times by XRD, XRF, TGA, multinuclear solid-state NMR, FTIR, SEM, TEM with EDS, XAS, and nitrogen sorption. The synthetic procedure involved hydrothermal crystallization of the gel with the following composition: 1SiO:0.54TEAOH:0.