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type II active phases with more brim active sites. This study
provides a promising candidate, which may offer new opportu-
nities for processing catalytic reactions of heavy crude oil in-
volving large molecules with high performance.
Characterization of the supports and the corresponding
catalysts
The supports and catalysts were characterized by small-angle X-ray
scattering (SAXS), X-ray powder diffraction (XRD), N2 adsorption–
desorption, high-resolution transmission electron microscopy
(HRTEM), scanning electron microscopy (SEM), inductively coupled
plasma-optical emission spectrometry (ICP-OES), Raman spectros-
copy, X-ray photoelectron spectroscopy (XPS), H2-TPR, and 27Al
solid-state magic-angle spinning nuclear magnetic resonance (27Al
MAS NMR).
Experimental Section
Chemicals
(NH4)6Mo7O24·4H2O (ꢀ99.0%), Ni(NO3)2·6H2O (ꢀ99.0%), hydro-
chloric acid (HCl, with a concentration of 36ꢁ38%), aluminum iso-
propoxide (C3H8AlO, ꢀ98.0%), 1,3,5-trimethylbenzene (C9H12,
ꢀ98.0%), tetraethyl orthosilicate (Si(OC2H5)4), and isopropanol
(C3H80, ꢀ99.7%) were purchased from Sinopharm (Beijing) Chemi-
cal Reagent Co., Ltd. (P.R. China). Triblock copolymer P123 (Aldrich,
EO20PO70EO20, PO: propylene oxide, EO: ethylene oxide; Mw =
5800 gmolÀ1) was obtained from Aldrich Company Ltd in USA.
SAXS measurements were taken on a NanoSTAR small-angle X-ray
scattering system (Bruker, Germany) using CuKa radiation (40 kV,
35 mA). The wide-angle XRD patterns were measured on a powder
X-ray diffractometer (Shimadzu XRD 6000) using CuKa (l=
0.15406 nm) radiation and with a scanning rate of 48/min.
N2 physisorption tests of the prepared supports and corresponding
catalysts were performed on a Micromeritics Tristar 3020 instru-
ment. The prepared samples were degassed in the preparation sta-
tion at 3508C under vacuum, and were then switched to the analy-
sis station for adsorption–desorption at À1968C. The specific sur-
face areas were calculated by using adsorption data with the Bru-
nauer–Emmett–Teller (BET) method. The pore sizes and the
window sizes of Al-SMCFs-x materials were derived from the ad-
sorption and desorption branches of the N2-sorption isotherms, re-
spectively, according to a modified Broekhoff-de Boer method
(BdB-FHH)[47] because this method is generally utilized to measure
spherical mesopores.[37,41] The total pore volumes (Vp) were estimat-
ed from the adsorbed amount at a relative pressure P/P0 of 0.99.
Preparation of the supports
Synthesis of SMCFs particles
P123 (2.0 g) was added into a clean and dry beaker followed by
2.0m HCl solution (60.0 mL). The obtained mixture was stirred at
308 K until well-dissolved. After dissolution, a certain amount of
TMB (1ꢁ3 g) was slowly added into the beaker and the mixture
was stirred for 45 min. Then, tetraethyl orthosilicate (TEOS, 6.4 g)
was added. The above mixture was stirred constantly for ten mi-
nutes and then kept for 24 h under a static condition in a water
bath at 308 K. Later, the obtained mixture was moved into an auto-
clave for 24 h hydrothermal treatment at 393 k. To obtain a series
of SMCFs with different pore sizes, the TMB/P123 mass ratio was
tuned from 0.5 to 1.5. The final obtained samples were collected
by washing, filtration, and drying in air for 24 h at 353 K, and final-
ly, calcined at 823 K for 6 h. The obtained products were denoted
as SMCFs-x, where SMCFs represents the spherical mesocellular
silica foams and x represents the mass ratio of TMB/P123.
SEM images were obtained from an FEI Quanta 200F apparatus
with the operating voltage of 20 KV. HRTEM was conducted on
a JEOL JEM-2100 instrument and the acceleration voltage was
200 kV. The Raman spectra of the prepared catalysts were collected
by an inVia Raman spectrometer (Renishaw). A laser wavelength of
532 nm and 8 mW power were used in this testing processing. ICP-
OES analyses were conducted on a PerkinElmer OPTIMA 7000 DV
analyzer after the samples were fully dissolved in HF solution.
XPS measurements of the sulfided catalysts were taken on a VG
ESCA Lab 250 spectrometer using AlKa radiation. The oxidic-state
catalysts were first sulfided with a mixture of 2 wt% CS2 in cyclo-
hexane solution at 3608C for 4 h, cooled to RT in a nitrogen flow,
ground, and then kept in cyclohexane to prevent oxidation. All the
analyzed catalysts needed to be pressed onto a stainless steel
sample holder in air before testing, the holder was then quickly
mounted on the XPS instrument. All binding energies (BE) were
calibrated based on C1s of adventitious carbon (285.0 eV). The
XPSPEAK software with the version 4.1[15] was employed to quanti-
fy the contents of Mo4+, Mo5+, and Mo6+ species.
Synthesis of aluminum-decorated SMCFs
The Al-modified SMCFs supports with a definite Si/Al molar ratio of
15 (defined as Al-SMCFs-x), were synthesized by a post-modified
method.[44] First, SMCFs (1.0 g) was added to an isopropanol solu-
tion (100 mL) and stirred for several minutes. Then, a certain
amount of aluminum isopropoxide was added into the above mix-
ture, which was kept stirring for 12 h. Finally, the obtained samples
were collected by washing with isopropanol, filtration, drying in air
for 24 h at 353 K, and calcination at 823 K for 5 h.
27Al MAS NMR experiments were performed on a Bruker ADVANCE
III 600 spectrometer at a resonance frequency of 156.4 MHz by
using a 4 mm HX double-resonance MAS probe at a sample spin-
ning rate of 15 kHz. The chemical shift of 27Al was referenced to
1m aqueous Al(NO3)3. 27Al MAS NMR spectra were recorded by the
small-flip angle technique with a pulse length of 0.5 ms (<p/12),
a recycle delay of 1 s, and 3000 scans.
Preparation of the NiMo/Al-SMCFs-x catalysts
A two-step incipient wetness impregnation method was utilized to
prepared NiMo supported on Al-SMCFs-x catalysts (NiMo/Al-
SMCFs-x). First, the Mo precursor ((NH4)6Mo7O24·4H2O) was impreg-
nated, then the Ni precursor (Ni(NO3)2·6H2O) was dipped. For every
dipping step, the obtained samples were dried at 383 K in air for
24 h and then calcined at 823 K for 4 h. All of the prepared cata-
lysts kept the same active metals contents (MoO3 15.5 wt% and
NiO 3.5 wt%).
Temperature-programmed reduction with H2 (H2-TPR) of the
sample was performed on a TP-5080 multifunction adsorption in-
strument. First, the sample (100 mg) was pretreated in an Ar
stream at 4008C for 2 h and then cooled to 508C. Later, the Ar
flow was switched to a 10% H2/N2 atmosphere and the catalyst
sample was heated to 10008C with a temperature rising rate of
ChemCatChem 2015, 7, 1948 – 1960
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