Figure 4.

XRD results of a 15 wt % Co/TiO₂ FTS catalyst during FTS at atmospheric pressure and at 250 °C. A) XRD patterns as a function of time under FTS conditions. Black indicates low diffracted intensity, and white means high intensity. The peak at 2θ of 12° is not shown completely to increase the visibility of the other diffraction peaks. B) The composition of the catalyst as a function of time on stream. The contributions of different Co species are plotted; standard deviations from the fit are indicated as the shaded area around the lines. C) Particle sizes of three of the Co species as a function of time on stream. Standard deviations are shown as the shaded area. D) Selected experimental diffractograms (full lines) and the Rietveld refinements (dashed lines) at the time points as indicated in Figure B and C. Peak positions for the Co species are indicated by vertical lines. Diffraction peaks attributable to TiO₂ support peaks and minor diffraction lines are not indicated.