On the crystal structure of heterogeneous catalysts at reaction-conditions: “in-situ” X-ray powder diffraction

In the field of heterogeneous catalysis there is an increasing need for the X-ray diffraction of catalyst compounds at elevated temperatures, especially under atmospheres comparable to those used in industrial applications. An “in-situ” diffraction system is presented which has a built-in high temperature chamber suitable for the use of inert (N2, Ar), oxidising (O2), reducing (H2) or organic atmospheres. This has been combined with a mass spectrometer for evolved gas analysis. Investigations of the thermal decomposition of silver(I)oxide (Ag2O) and the behaviour of the heteropoly catalyst H4[PVMo11O40] · n H2O during the oxydehydrogenation of isobutyric acid clearly show the usefulness of the presented apparatus