The application of synchrotron methods in characterizing iron and cobalt Fischer–Tropsch synthesis catalysts

• TPR-EXAFS/XANES provides a transparent picture of reduction steps during activation.
• The impact of promoters on H2-reduction/CO-carburization rates can be assessed.
• Pt, Re, and Ru promoters are typically atomically coordinated to Co after activation.
• Links between promoter local atomic structure and selectivity can be obtained.
• Catalyst deactivation and sensitivity to H2O can be examined by synchrotron methods.

This article reviews the use of synchrotron radiation techniques to confront issues associated with cobalt and iron catalysts. The main areas that are examined include: (1) the application of TPR-XANES and TPR-EXAFS to gain insight into the hydrogen reduction of cobalt catalysts and the carburization of iron catalysts; (2) the impact of promoters on these reduction/carburization rates; (3) the local atomic structure of promoters and its influence on catalyst selectivity; (4) exploring the deactivation of cobalt catalysts; (5) the influence of crystallite size in stabilizing cobalts catalyst against water effects; and (6) temperature effects in alkali promoted iron catalysts in retaining the iron carbide phase against reoxidation by water.

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