Temperature-programmed reaction study of carbon transformations on iron fischer-tropsch catalysts during steady-state synthesis

摘要: Temperature-programmed surface reaction (TPSR) in hydrogen was used to differentiate up seven different carbon types on iron Fischer-Tropsch (FT) catalysts. Both K-free and K-promoted catalysts were pretreated 1:1 H2/CO syngas for 6–18 hours achieve well-developed coverages. Reaction temperatures of 215 245°C selected, provide conditions steady-state activity (no apparent deactivation) relatively rapid deactivation. Possible forms the catalyst include (1&2) atomic planar edge sites, (3) Hagg carbide, (4) epsilon-carbide, (5) amorphous (6) moderately- (7) well-ordered graphitic carbons. Deactivation FT synthesis under this study is associated with (1) transformation high Hagg-carbide less active epsilon-carbide (2) formation a highly ordered graphite catalyst.