III International Conference

PP-II-7SPATIALLY RESOLVED UV-VIS MICRO-SPECTROSCOPY:A PHYSICOCHEMICAL STUDY ON THE PREPARATION OF METAL-IONSUPPORTED CATALYST EXTRUDATESAlonso L.E., de Jong K.P., Weckhuysen B.M.Inorganic Chemistry and Catalysis Group, Department of Chemistry, Utrecht University,The NetherlandsE-mail: l.espinosaalonso@chem.uu.nlSpatially resolved UV-Vis micro-spectroscopy is a newly developed technique to studythe physicochemical processes involved in the elementary steps (impregnation and drying) ofmm-sized catalyst extrudates preparation. The metal ions under study were Ni 2+ , Cu 2+ , Pd IIand Pt IV . Different preparation conditions were used (PZC, ionic strength, drying temperatureand nature of the complexes in solution) in order to monitor the influence of them on themetal ion distribution or speciation. By following the d-d and charge transfer transition bandsof the respective metal ion complexes during impregnation and after drying it was possible toobserve different distributions by modifying the PZC, the ionic strength or the nature of theligands in the solution and different species being formed as a function of the position insidethe catalyst extrudates as a function of the drying temperature.Introduction The elemental steps of impregnation and drying in the preparation ofdifferent hydrogenation catalysts containing Ni 2+ , Cu 2+ , Pd II and Pt IV were under study. To doso, a newly developed technique was applied, UV-Vis micro-spectroscopy, which is able tomonitor the physico-chemical processes involved during the preparation of mm-sizedsupported catalysts with both spatial and time resolution.UV-Vis micro-spectroscopyAg g fg gg gBFigure 1. UV-Vis micro-spectrometer. (A) Scheme of the set-up: (a) UV-Vis probe,(b) measuring cell, (c) movable platform, (d) sample holder. UV-Vis probe formed by onecollecting fiber (f) and six illuminating fibers (g). (B) Illustration of the set-up.UV-Vis micro-spectroscopy enables monitoring the metal-ion speciation along the crosssection of bisected catalyst bodies in the UV-visible-NIR region (250-1100 nm) with a spatial171