The application of Mössbauer emission spectroscopy to industrial cobalt based Fischer–Tropsch catalysts

Abstract

57Co-Mössbauer emission spectroscopy (MES) has been used to study the oxidation of cobalt as a deactivation mechanism of high loading cobalt based Fischer–Tropsch catalysts for the gas-to-liquids process. It was reported previously [Catal. Today 58 (2000) 321; Proceedings of the International Symposium on the Industrial Applications of the Mössbauer Effect, 13–18 August, 2000, Virginia Beach, VA] that oxidation was observed at atmospheric pressure under conditions that were in contradiction with the bulk cobalt phase thermodynamics. A high-pressure MES cell was designed and constructed, which created the opportunity to study the oxidation of cobalt based Fischer–Tropsch catalysts under realistic synthesis conditions. The cobalt catalyst preparation procedure was investigated by means of 57Fe-Mössbauer absorption spectroscopy, applying 57Fe as a probe atom. Initial results indicate, although not yet conclusive, that a 57Co-MES catalyst can be prepared from the industrial prepared standard Co catalyst by an additional simple incipient wetness impregnation procedure.