Deactivation study on a coprecipitated Fe-Cu-K-Al catalyst in CO2 hydrogenation

The deactivation of a coprecipitated Fe-Cu-K-Al catalyst has been studied in CO2 hydrogenation to hydrocarbons. After the catalyst had been employed in the reaction for 1500 h at 300 degreesC, 10 atm and space velocity of 1800 ml/g(cat) h, it started to show significant decreases in the catalytic activity and selectivity. A long-term (2000 h) reaction test led to 13% reduction in the hydrocarbon synthesis activity. The characterizations have been carried out by means of elemental analysis, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Mossbauer spectroscopy for the fresh catalyst, the activated catalyst and the deactivated catalyst. From the results, it can be deduced that the catalyst deactivation was caused by the increase in crystallinity of iron species, thus leading to the phase separation of Fe, Cu, At and K. (C) 2001 Elsevier Science B.V. All rights reserved.