Heterogeneously catalysed partial oxidation of acrolein to acrylic acid--structure, function and dynamics of the V-Mo-W mixed oxides.

摘要: The major objective of this research project was to reach a microscopic understanding the structure, function and dynamics V-Mo-(W) mixed oxides for partial oxidation acrolein acrylic acid. Different model catalysts (from binary ternary vanadium molybdenum up quaternary with additional tungsten) were prepared via solid state preparation route hydrochemical precursors by spray-drying or crystallisation subsequent calcination. phase composition investigated ex situ XRD HR-TEM. Solid samples are characterised crystalline phases associated suitable diagrams. Samples from crystallised spray-dried show which not part diagram. Amorphous nanocrystalline structures only found in tungsten doped samples. kinetics as well catalysts' structure have been studied XAS, XRD, temperature programmed reaction reduction transient isotopic tracing technique (SSITKA). re-oxidation bulk evaluated XAS. A direct influence but also is shown. Altogether correlations drawn between oxygen catalytic performance terms activity, selectivity long-term stability. behaviour under conditions has developed. Furthermore, isotope exchange experiments provided closer image mechanism selective oxidation. Based on characterisation combination micro kinetic modelling detailed describes processes at catalyst more precisely discussed.