Nanostructural Analysis of Co-Re/γ-Al2O3 Fischer-Tropsch Catalyst by TEM and XRD

A rhenium promoted Fischer-Tropsch (FT) cobalt catalyst supported on gamma-Al2O3 has been investigated by Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD), before and after reduction. Electron diffraction, High Resolution TEM and Electron Energy Loss Spectroscopy were used to confirm the oxidation state. Cobalt aggregate, particle and crystallite sizes have been studied in detail and measured by TEM and XRD. A cobalt particle size of 10.0 +/- 2.4 nm obtained from bright field TEM images for the reduced material is consistent with the XRD analysis of the calcined catalyst. After reduction dark field TEM imaging gave a volume-weighted crystallite size of 7.5 +/- 2.5 nm, which is close to the value obtained by XRD. The particles had lost the parallel orientation and physical continuity within the alumina pore structure that were present before reduction. The latter was confirmed by electron tomography. Lamellae identified with the presence of Hexagonal Close Packed cobalt were observed in the predominantly Face Centred Cubic particles.

Automated summary

The structure of a rhenium promoted Fischer-Tropsch cobalt catalyst supported on gamma-Al2O3 was investigated using TEM and XRD. The size and morphology of cobalt aggregates, particles, and crystallites were analyzed in different states. This study provides important information for understanding the relationship between catalyst structure and performance.