Rj. Kalenczuk, EFFECT OF COBALT ON THE MORPHOLOGY AND ACTIVITY OF FUSED IRON CATALYST FOR AMMONIA-SYNTHESIS, Applied catalysis. A, General, 112(2), 1994, pp. 149-160
BET, scanning electron microscopy, X-ray diffraction, Mossbauer spectr
oscopy and X-ray florescence spectroscopy were used to investigate the
effect of cobalt on the morphology and activity of fused iron catalys
t for ammonia synthesis. Activity tests were carried out under 10 MPa
in the 350-450-degrees-C temperature range. Investigations were perfor
med on the traditional multipromoted iron catalyst and on a series of
catalysts prepared with addition of cobalt. Introduction of cobalt inc
reased the activity of the iron catalyst. The maximum effect was obser
ved for 5.5 wt.-% Co. Moreover, activating action was stronger at lowe
r temperatures. Addition of cobalt caused a change in catalysts struct
ure. Co2+ ions were incorporated in the crystal lattice of wustite and
magnetite. They changed the surface structure and the relation Fe2+/F
e3+, however the relation of bivalent to threevalent metal ions was no
t affected. The change of the catalyst structure in the unreduced form
produced a catalyst that possessed other surface properties. The most
active catalyst adsorbed less nitrogen than those without cobalt.