Characterization of oxide catalysts by in situ Moessbauer spectroscopy

Chemical and structural information as obtained by Moessbauer spectroscopy when applied on the study of the catalysts under controlled temperature and pressure of the sample environment or under conditions close to the reaction ones is reviewed. Several cells for these in situ or operando measurements, respectively, are described: working at high and/or low temperature, under vacuum or rather high pressure, in a static atmosphere or in a flow, in gas or liquid phase, in the presence of magnetic fields or by applying the electric field. Examples of catalytic reactions being studied in such in situ cells are given, focusing on the oxide catalysts either crystalline or amorphous or on the oxide supported catalysts. The advantages of in situ measurements were noticed, especially for unraveling the reaction mechanism. (authors)