Development of new trimetallic NiMoW catalysts supported on SBA-15 for deep hydrodesulfurization

Mesoporous zeolite-supported metal sulfide catalysts with high activities in the deep hydrogenation of phenanthrene

“…Generally, the absorption band at 230-260 nm is attributed to the isolated molybdate species in tetrahedral coordination, whereas the band at 270-330 nm is characteristic of polymeric octahedral Mo species [31,53]. In our case, the absorption band around at 250 nm for NiMo/c-Al 2 ) [54][55][56] (Fig. 8).…”

“…The polymolybdates are considered to interact weakly with the support, resulting in higher reducibility and activity during the hydrogenation reaction [54,56]. However, a shoulder band is observed at 895 cm À1 on the NiMo/c-Al 2 O 3 that can be attributed to the Mo@O stretching mode of the isolated MoO 4 2À with distorted tetrahedral symmetry [55,57]. This Mo species present relatively low reducibility during the catalyst sulfidation due to the strong interaction of the Mo with the c-Al 2 O 3 via MoAOAAl bridges [50,58].…”

Desilication and silylation of Mo/HZSM-5 for methane dehydroaromatization

“…It is worthwhile to discuss the differences in the spectra following various treatments. The spectrum of Mo/HZSM-5 contains a pronounced feature at 970 cm À1 due to the Mo@O stretch of dimeric Mo structures inside the micropores [15] with a shoulder at 953 cm À1 (highly dispersed octahedral molybdenum surface species [33]) on top of the broad 960-970 cm À1 band. The peak at 970 cm À1 is not visible for Mo/HZSM-5(Mo,Si1) and Mo/HZSM-5 (Mo,Si3).…”

Influence of Na content on behavior of NiMo catalysts supported on titania nanotubes in hydrodesulfurization

“…This pathway yields first tetrahydrodibenzothiophene (THDBT) and then the corresponding cyclohexylbenzene [53,54]. However, in the presence of HDS catalysts with higher hydrogenation activity, DBT can also react through the HYD pathway [40,55,56]. This makes dibenzothiophene an appropriate model compound for laboratory HDS tests, since it makes it possible to characterize both the hydrogenolysis and hydrogenation functions of the catalyst.…”