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 i n CO2 hydrogenation to hydrocarbons. After the catalyst had been employed i n the reaction for 1500 h at 300 degreesC, 10 atm and space velocity of 180 0 ml/g(cat) h, it started to show significant decreases in the catalytic ac tivity and selectivity. A long-term (2000 h) reaction test led to 13% reduc tion 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 res ults, it can be deduced that the catalyst deactivation was caused by the in crease in crystallinity of iron species, thus leading to the phase separati on of Fe, Cu, At and K. (C) 2001 Elsevier Science B.V. All rights reserved.