Sulfidation of carbon-supported iron oxide catalysts

Mössbauer emission and absorption studies on the reduction behaviour of supported Co, Co−Mo, Fe and Fe−Mo hydrotreating catalysts

“…Again, the spectra of these catalysts consist of Fe(III)oxide uptill reduction at 473 K. The dispersion of the Fe species in the Mo-containing precursor is very high, which follows from the very large surface-oxide contribution. This is in accordance with the observation of Ramselaar et al [5] from 4.2 K measurements on these catalysts.…”

“…Ramselaar et al [3][4][5] studied sulfidic Fe and Fe-Mo catalysts by M/Sssbauer absorption spectroscopy (MAS). In the case of sulfidic carbon-supported catalysts they observed a large influence of Mo on the Fe phases formed.…”

The influence of phosphorus on the structure and hydrodesulfurization activity of sulfided Fe and Fe-Mo catalysts supported on carbon and alumina

“…The results of the computer analyses are given in Table i. From comparison of the results presented in this Table and those obtained earlier for sulfided Fe and Fe-Mo catalysts on carbon [23][24][25][26] and alumina [24,2?] supports it follows that the spectral contributions with the smaller quadrupole splittings (indicated by a full bar-diagram in the Figures 3 and 4) are due to sulfided iron species, assigned to "Fel_xS", "Fe-S" and "Fe-Mo-S".…”

“…An alternative explanation is that, due to a metalphosphate interaction, transportation of the metal oxide phase towards the outer pores of the support grains and subsequent sintering of crystalline oxide aggregates during the drying procedure [23,24] is hampered.…”

“…In the Fe(4.3)/C+P(I.5) catalyst almost all the iron is present in the form of this phase, and hence its HDS activity is close to zero. At low P content, a large part of the iron atoms are not complexed with P and can be sulfided into the catalytically active "Fel_xS" phase [23,24].…”