shows
the CO chemisorption isotherms for the -Mo2C/Al2O3 catalyst that
resulted in a CO chemisorption value of 485 mol of CO per gram of
carbide. This is a very high value if compared to the CO chemisorption
values obtained for bulk molybdenum carbide that are in the
range of 100 mol of CO per gram [30].
Assuming that he CO chemisorption in Mo2C indeed has
1:1 stoichiometry has proposed by Nagai et al. [29], then the
number of molybdenum atoms titrated by 485 mol of CO
would be 2.92
×
1020. Because in 1 g of Mo2C the number of
molybdenum atoms 5.01
×
1021 then a dispersion of ca. 0.05
(D = 4.97
×
1019/5.03
×
1020) would be found for molybdenum carbide.
Despite low, this dispersion is similar to that of 0.05 reported
by Dhandapani et al. [31] for a 40 wt.% Mo2C/Al2O3 catalyst where
the diffraction lines for the Mo2C were barely seen. Due to the high
content of carbide formed in this study after the carburization step
(17.02 wt.%) one would expect to see some of the diffraction lines
of Mo2C a fact not observed. Therefore this result either indicates
that carburization was not complete or that the formed material is
amorphous.