Błachucki, Wojciech Szlachetko, Jakub Kayser, Yves Dousse, Jean-Claude Hoszowska, Joanna Zeeshan, Faisal Sá, Jacinto 2017-11-15 In the present work high energy resolution off-resonant X-ray spectroscopy (HEROS) was employed at a synchrotron to study a silica supported Ta(V) bisalkyl catalyst activated in hydrogen. The Ta Lα1 HEROS spectra were measured during oxidation of the starting complex and the relative species’ concentration was successfully retrieved as a function of time using the fingerprint HEROS spectra measured for the unoxidized and the oxidized catalyst. Based on the experimental data and theory- based calculations, it was shown that oxidation of the active Ta catalyst leads to the formation of mono- and di-meric species on the SiO2 surface. The obtained results were compared to those of the previously reported time-resolved HEROS study on an inactive silica supported Ta(V) bisalkyl catalyst’s concentration evolution during its oxidation Błachucki et al. (2015). The study allowed observation of an immediate transition of the active Ta catalyst from its unoxidized form to the oxidized one. This finding is dissimilar to the result of the study on the inactive Ta catalyst, where the oxidation led through an intermediate step. application/pdf https://folia.unifr.ch/global/documents/306288 https://folia.unifr.ch/documents/306288/files/dou_ish.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.1016/j.nimb.2016.11.029 info:eu-repo/semantics/openAccess License undefined Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. - 2017, vol. 411, no. Supplement C, p. 63–67 Synchrotron radiationTime-resolved high energy resolution off-resonant X-ray spectroscopyCatalysts info:eu-repo/classification/udc/53 In situ high energy resolution off-resonant spectroscopy applied to a time-resolved study of single site Ta catalyst during oxidation http://purl.org/coar/resource_type/c_6501