Premium
CO hydrogenation over supported cobalt catalysts: FTIR and gravimetric studies
Author(s) -
Fredriksen Geir R.,
Blekkan Edd A.,
Schanke Dag,
Holmen Anders
Publication year - 1995
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.270180207
Subject(s) - catalysis , cobalt , gravimetric analysis , chemistry , adsorption , fourier transform infrared spectroscopy , inorganic chemistry , hydrocarbon , infrared spectroscopy , absorption (acoustics) , materials science , chemical engineering , organic chemistry , engineering , composite material
The hydrogenation of CO over supported cobalt catalysts has been studied using in situ FTIR spectroscopy and gravimetry at P = 6 bar, T = 473–723 K and H 2 /CO = 2–3. On both silica‐ and alumina‐supported catalysts IR absorption bands corresponding to linearly adsorbed CO on metallic cobalt were observed. On alumina an additional pair of bands at lower frequencies was attributed to bridge‐bonded CO. Absorption bands corresponding to adsorbed hydrocarbons (3050–2700 cm −1 ) and to oxygen containing species (1800–1200 cm −1 ) were found to correspond to adsorbed products or unreactive species. The gravimetric studies showed a significant difference between the supports. On the silica‐supported catalyst the weight uptake decreased with increasing temperature (473–573 K). The weight increase during reaction was attributed to adsorbed hydrocarbon reaction products. On the alumina‐supported catalyst the weight uptake increased with increasing temperature, and there was also a significant weight increase with the support alone. Most of the weight uptake can be attributed to the formation of stable formate and carbonate species on the alumina support. At 723 K the deposits formed were stable in H 2 , and the shape of the curves indicated different mechanisms for deposition of material. In particular the Co/Al 2 O 3 sample showed a very high and linear rate of weight gain, which was an order of magnitude higher than for the other samples.