The Ni 2p XPS spectra of different sulfide catalysts are shown in Fig.
S16. Meanwhile, the peak-fitting data for Ni 2p species are displayed in
Table 4. The Ni species in XPS spectra include three kinds of NiMoS, NiS
and NiO.[51] The binding energy for NiMoS active
phase appears at 856.0±0.3 eV. The binding energies for Ni 2p1/2 and NiS
2p3/2 are 873.0±0.3 eV and 852.6±0.3 eV respectively. Moreover, the
binding energy appearing at 862.0±0.3 eV is ascribed to NiO
species.[52] It reveals that the proportion of
NiMoS phase exhibit the order of NiMo/SBA-16 (0.25) <
NiMo/AT-10 (0.28) < NiMo/AT-0 (0.37) < NiMo/AT-5
(0.38) < NiMo/AT-7.5 (0.41) < NiMo/AT-2.5 (0.42).
The proportion of NiMoS phase for the sulfide catalysts incorporated by
Al or Ti species, particularly Ti species is higher than that of
NiMo/SBA-16 catalyst. Therefore, it can demonstrate that appropriate Ti
modification can promote the distribution of active metals, which can
also be recognized from UV-vis DRS. It should be noteworthy that the
NiMoS phase is generally treated as active phase for HDS reaction.
Hence, the incorporation of Ti species into SBA-16 silica can improve
the HDS performance through improving the distribution of active metals.
Table 5 Mo edge and S edge concentration from CO-IR spectra.