IN-SITU XAFS SPECTROSCOPIC STUDIES OF DIRECT COAL-LIQUEFACTION CATALYSTS

An in situ cell capable of withstanding typical coal liquefaction reac tion conditions was designed and built for XAFS investigations. Three different Fe-based catalysts for direct coal liquefaction were studied at the reaction conditions of 1000 psig (cold) hydrogen pressure and up to 500 degrees C temperature, Both near-edge (XANES) and radial str ucture function (EXAFS) data showed gradual conversion from iron oxyhy droxide to pyrrhotite. The starting temperature and the temperature ra nge over which such transformations occur vary significantly with the catalyst system being investigated.