In situ characterization of iron phosphate and bismuth molybdate catalysts prepared by hydrothermal methods: An EDXRD and combined XRD/XAS study

Iron phosphates and bismuth molybdate catalysts have been successfully prepared employing hydrothermal methods. In situ energy dispersive X-ray diffraction (EDXRD) and combined X-ray diffraction/X-ray absorption spectroscopy (XRD/XAS) studies reveal that these solid-state materials are formed from the amorphous precursor gel without the formation of any intermediate phases. While the time-resolved EDXRD measurements allowed us to determine the kinetics of phase formation, the combined XRD/XAS shows that there are local structural modifications taking place during the production of the crystalline active phases.: More importantly the materials prepared by this hydrothermal method possess a much higher surface area as compared to the ones prepared by conventional methods. (C) 2002 Elsevier Science B.V. All rights reserved.