On Thursday 17 May 2007, Edward L. Kunkes wrote:
I am trying to determine the oxidation state of Re in PtRe nanoparticles catalysts supported on carbon. The ReLIII edge was measured before and after an in-situ reduction in hydrogen. Can anyone suggest Which characteristic of the edge is more related to oxidation state ? Is it the integrated white-line intensity or the position of the edge(point of maximum derivative). The edge position of the ReLIII edge of my particles is the same as that of Re foil, however the white line instensity is significanty higher. For the non-reduced PtRe particles, the edge position is similar to that of ReO2 (with a larger white line intensity).
I see that no one has responded to this, so I'll take a stab. Presumably you know what the end members -- Re metal and Re oxide -- look like. Can you do linear combination fitting of the intermediate spectra to determine the average oxidation? B -- Bruce Ravel ---------------------------------------------- bravel@anl.gov Molecular Environmental Science Group, Building 203, Room E-165 MRCAT, Sector 10, Advanced Photon Source, Building 433, Room B007 Argonne National Laboratory phone and voice mail: (1) 630 252 5033 Argonne IL 60439, USA fax: (1) 630 252 9793 My homepage: http://cars9.uchicago.edu/~ravel EXAFS software: http://cars9.uchicago.edu/~ravel/software/