Effect of promoters on the HDS activity of alumina-supported Co-Mo sulfide catalysts

Article abstract of DOI:10.1039/c5ra17414g

A series of CoMo/δ-Al₂O₃ catalysts promoted by different organic and inorganic cobalt salts were successfully prepared using low-cost δ-Al₂O₃ as a support through a two-step incipient-wetness impregnation method. The obtained catalysts were indicated as MoCo-N/δ, MoCo-S/δ, MoCo-A/δ and MoCo-D/δ, in which N, S, A, D, and δ represent cobalt nitrate, cobalt sulfate, cobalt acetate, cobalt diacetylmethane, and δ-Al₂O₃, respectively. The as-synthesized catalysts were introduced to the hydrodesulfurization (HDS) process of fluid catalytic cracking (FCC) diesel, in a fixed-bed reactor. The oxidized catalysts and the corresponding sulfurized catalysts for HDS were characterized by UV-vis, Raman, X-ray diffraction, TPR, and XPS techniques. The catalytic activities followed the order of MoCo-A/δ < MoCo-N/δ < MoCo-D/δ < MoCo-S/δ. These catalytic results could be ascribed to the introduction of different cobalt salts decreasing the metal-support interaction (MSI), and led to the formation of easily reduced Mo species, which were the precursors to form more active sites that could enhance the HDS activity of the catalysts. The highest activity shown by the MoCo-S/δ catalyst could be ascribed to its (1) higher metal dispersion, (2) lower Mo reduction temperature, and (3) higher sulfurization degree. As a result, the excellent catalytic performance could be attributed to its outstanding promoter effect.

Full text of DOI:10.1039/c5ra17414g

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Effect of promoter on the HDS activity of aluminaꢀ
supported CoꢀMo sulfide catalysts
Cite this: DOI: 10.1039/x0xx00000x
1
1,2†
1
1
1
Xilong Wang , He Fang , Zhen Zhao , Aijun Duan *, Chunming Xu *, Zhentao
1
1
1
1
1
3
Chen , Minghui Zhang , Peng Du , Shaotong Song , Peng Zheng , Kebin Chi
Received 00th January 2012,
Accepted 00th January 2012
A series of CoMo/δꢀAl
successfully prepared using lowꢀcost δꢀAl
impregnation method. The obtained catalysts were indicated as MoCoꢀN/δ
A/δ and MoCoꢀD/δ, in which N, S, A, D, and δ represent cobalt nitrate, cobalt sulfate, cobalt
acetate, cobalt diacetylmethane, and δꢀAl , respectively. The asꢀsynthesized catalysts were
2
O
3
catalysts promoted by different organic and inorganic cobalt salts were
as supports through a twoꢀstep incipientꢀwetness
MoCoꢀS/δ MoCoꢀ
DOI: 10.1039/x0xx00000x
2 3
O
、
、
www.rsc.org/
2
O
3
introduced to the hydrodesulfurization (HDS) process of fluid catalytic cracking (FCC) diesel, in a
fixedꢀbed reactor. The oxidized catalysts and the corresponding sulfurized catalysts for HDS
were characterized by UVꢀVis, Raman, Xꢀray diffraction, TPR, and XPS techniques. The catalytic
activities followed the order of MoCoꢀA/δ
< MoCoꢀN/δ < MoCoꢀD/δ < MoCoꢀS/δ. These catalytic
results could be ascribed to the introduction of different cobalt salts decreasing the metalꢀsupport
interaction(MSI), and led to the formation of easily reduced Mo species, which were the
precursors to form more active sites that could enhance HDS activity of the catalysts. The
highest activity shown by the catalyst of MoCoꢀS/δ could be ascribed to its (1) higher metal
dispersion, (2) lower Mo reduction temperature, and (3) higher sulfurization degree. As a result,
the excellent catalytic performance could be attributed to its outstanding promoter effect.
1
.
Introduction
introducing the promoter metal onto MoS /support to get the
2
supported promoted phase, as proposed by several research
groups.
The development of highly active hydrodesulfurization (HDS)
catalysts has been one of the principal issues in the petroleum
industry to meet the ever increasing stringent environmental
8,9
In recent years, the configuration of active phases and the
promotion effect of Co/Ni on the supported or bulk Mo sulfides
evoke the attention of researchers in improving HDS
1,2
regulations. Mo or W sulfide catalysts promoted by Co or Ni
on alumina are widely used in HDS processes due to their high
10,11
performance of the catalysts. Candia et al.
revealed that the
3,4
selectivity and activity. It is generally believed that the active
sulfidation of MoS2 particles decreased the interactions
phase of CoꢀMo HDS catalysts is soꢀcalled “CoMoS” phase, in
between MoS particles and the support material, leading to the
5
2
which Co atoms are located on the edge of MoS particles.
2
formation of type II CoMoS phase. Moreover, they found that
HDS reactivity was linearly correlated to the amount of CoMoS
During the preparation the individual sulfide species like Co9S8
are formed, leading to a loss of promoter to the detriment of the
12 , 13
phase.
The formation of the CoꢀMo sulfide species
6,7
active phase, which prevents the promoter incorporated into
the active phase and thus decreases the reactivity. A better
control of the location of the promoter could be obtained by
explained the generation of strong catalytic synergies between
Co and Mo. Some research groups have reported the main
14,15
focuses, including the Co or Ni promoters,
their roles in
modifying active nanoparticle morphologies, and the active site
16
17
performance. Schweiger et al. reported that for Moꢀedge
fully promoted by Co at high chemical potential, Co was
situated on both edges with 100% sulfur coverage while Sꢀedge
with 50% sulfur coverage and the Co atoms on the Moꢀedge
were energetically less favorable. Bezverkhyy et al. used
cobalt acetylacetonate as Co precursor to promote molybdenum
sulfide supported on alumina, and found that the solids could be
directly used as catalyst without resulfidation. They also proved
1
State Key Laboratory of Heavy Oil Processing, China University of Petroleum,
Beijing 102249, P. R. China;
Yunnan Yuntianhua Petrochemical Co., Ltd.,Yunnan, 650300, P.R. China;
Petrochemical Research Institute, PetroChina Company Limited, Beijing 100195,
P. R. China;
2
3
18
[†] This author has equal contribution as the first author
*
*
Aijun Duan: Email: duanaijun@cup.edu.cn; Tel: 86-10-89732290
Chunming Xu: xcm@cup.edu.cn; Tel: 86-10-89733392
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that the use of Co(NO ) •6H O as Co source led to a weaker and cobalt acetate (Sinopharm Chemical Reagent, 99.5wt%),
3
2
2
19,20
synergetic effect. Okamoto et al.
found that CoMoS phases deionized water was used as solvent. For impregnating cobalt
were selectively formed by use of Co(CO) NO as a precursor in diacetylmethane (Sinopharm Chemical Reagent, 99.0wt%),
3
which the Mo content was fixed approximately at a monolayer methanol was used as solvent. The obtained catalysts were
21
loading. Gandubert et al.
used Xꢀray photoelectron indicated as MoCoꢀN/δ、MoCoꢀS/δ、MoCoꢀA/δ and MoCoꢀ
spectroscopy (XPS) in conjunction with DFT, suggesting that D/δ, in which N, S, A, D, and δ represent cobalt nitrate, cobalt
CoꢀMo mixed sites on the Moꢀedge were active for the sulfate, cobalt acetate, cobalt diacetylmethane, and δꢀAl O ,
2
3
hydrogenation of toluene, while the Sꢀedge fully promoted by respectively. The metal compositions of the catalysts were 12
Co showed a lower activity.
wt.% of MoO and 3 wt.% of CoO.
3
Many studies have shown that the hydrogenation activity of
MoO /Al O could be dramatically improved by the
2
.2 Characterization of the catalysts
3
2
3
o
introduction of Co, and the bimetallic synergy was helpful for The wide–angle (2θ = 5.0–80.0 ) X–ray diffraction patterns
the generation of highly active CoMoS phase. The cobalt nitrate were determined on a Rigaku RINT D/Maxꢀ2500 powder
is generally used in the traditional CoMo catalyst. It is reported diffraction system, using the Cu Kα radiation at 40 kV and 50
that different cobalt sources had great influence on the activities mA. The UV–Vis diffuse reflectance spectra of the catalysts
of catalysts. However, the effect of different cobalt salts on the were recorded using a UV–Vis spectrophotometer (Hitachi Uꢀ
HDS activity of catalysts was rarely reported and lack of 4100). The powder catalysts were characterized in the 200–800
systematic research.
nm range at room temperature. H –TPR experiments of the
2
In this work, firstly, δꢀAl O was used as the support material catalysts were performed on a Quantachrome apparatus (Autoꢀ
2
3
and the supported CoMo catalysts promoted by different sorbꢀiQ, USA) in a 10% H /Ar flow at 40 ml/min. The Raman
2
organic and inorganic cobalt salts were synthesized by spectra for the catalysts were recorded on a Raman microscope
incipientꢀwetness impregnation method. Secondly, a series of (SpectraꢀPhysics model 163), operated at the laser wavelength
supported CoMo catalysts for HDS were characterized by UVꢀ of 532 nm. X–ray photoelectron spectroscopy (XPS) analyses
Vis, Raman, XRD, TPR, and XPS techniques. Finally, the of the sulfided catalysts were carried out in a Thermo Fisher K–
effect of different organic and inorganic cobalt salts on the FCC Alpha spectrometer equipped with an analyser mode of CAE
diesel HDS activity was investigated to obtain the catalyst with operating at a fixed pass energy of 40 ev and working under
ꢀ
9
the best performance.
Experimental
.1 Preparation of the catalyst
vacuum (<10 mbar). All the data were acquired using Kα (hv
1486.6 ev), and the binding energy were calibrated taking C
=
2
.
1s (BE = 284.6 ev) as an internal standard. Before analysis, the
catalysts were freshly presulfided according to the same
sulfidation procedure as the catalytic activity evaluation, and
2
The δꢀAl O was prepared by calcination of the hydrated stored under cyclohexane to prevent oxidation.
2
3
boehmite, bought from Zhengzhou Aluminum Industry
Research Institute, in air at 1173 K for 5 h with the heating rate
2
.3 Catalytic performance evaluation
ꢀ
1
of 2 K min . Active metal components of Mo and Co were The HDS activity tests were evaluated in a fixedꢀbed reactor
stepwise loaded on the δꢀAl O3 supports via a twoꢀstep
= 9 mm, = 50 cm) with 2 g (40ꢀ60 mesh) catalyst using
incipient wetness method impregnated with aqueous solutions Hohhot FCC diesel with the sulfur content of 1013.78 µg·ml
of heptamolybdate tetrahydrate ((NH ) Mo O •4H O
as feedstock. The weighted catalyst was presulfided with 2 wt%
(
D
L
2
ꢀ
1
，
4
6
7
24
2
Sinopharm Chemical Reagent, 99.0wt%) and cobalt salts. The CS
in cyclohexane, 4.0 MPa, 593 K, H
/cyclohexane ratio of
2
2
ꢀ
1
details of the preparation were shown as follows:
600 ml/ml and weight hourly space velocity (WHSV) of 1.0 h
A certain amount of ammonium molybdate was dissolved in for 4.0 h. After sulfidation, the HDS reactions were performed
ꢀ
1
deionized water and then Al O was added into the solution. at 623 K, 5.0 MPa, 600 ml/ml and 1.0 h . The liquid product
2
3
After impregnation, the samples were dispersed by ultrasonic was collected at steady state after 9 h on stream. The HDS
for 15 min, dehydrated at 110 for 2 h and calcinated at 550
activities (η) are calculated as η = (S ꢀS )/S , where S refers to
for 6 h to obtain a series of Mo/supporters. Cobalt salts were the content of sulphur in feed, and S refers to the content of
introduced by incipientꢀwetness impregnation method sulphur in products. The sulfur contents were tested by a RPPꢀ
according to the solubility, the details were as follows:
2000SN sulfur and nitrogen analyzer (Taizhou Central
A certain amount of cobalt salts were dissolved in certain Instruments Co. Ltd. P.R. China) The test deviation of the
℃
℃
f
p
f
f
p
,
ꢀ
1
solvents and Mo/supporter catalyst was added in. Then the sulfur analyzer is 1 µg·ml , therefore, the deviations of HDS
samples were dispersed by ultrasonic for 20 min, dehydrated at efficiency are around 0.10%.
110℃for 2 h and calcinated at 550℃for 6 h to obtain a series
of CoMo supported catalysts. The obtained catalyst was 3. Results and discussion
squashed and broken into particles with 40ꢀ60 mesh.
For dissolving different cobalt species, including cobalt nitrate
3
3
.1 Characterization of catalysts
(
(
Sinopharm Chemical Reagent, 98.5wt%), cobalt sulfate
Tianjin Guangfu Fine Chemical Research Institute, 99.5wt%)
.1.1 XRD characterization of the oxide CoMo catalysts
2
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A
17
R
4
T
14IC
G
LE
Fig.1 shows the wide–angle XRD spectrogram of the catalysts polymetric
with δꢀAl O as supporter and different cobalt salts as respectively.
octahedral
coordination
Mo(O)
species,
23
2
3
promoters. The intensity of characteristic peaks of δꢀAl O3
（
The asꢀprepared catalysts present three successive absorption
2
2
θ=66.95°, 45.62°, 46.48° and 37.6°
）decrease after the peaks between 500ꢀ650 nm, which are ascribed to the
24
loading of active metals, and the characteristic peak at 2θ=26.8° tetrahedron coordination divalent Co species. Besides, the
belongs to βꢀCoMoO , as shown in Fig.1. For different cobalt adsorption peak of 590 nm belongs to the characteristic peak of
22
4
salts, the intensities of the characteristic peaks are different and βꢀCoMoO . The intensity of this adsorption peak increases as
4
increase as the following order: MoCoꢀS/δ
<
MoCoꢀD/δ
<
the following order: MoCoꢀS/δ < MoCoꢀD/δ < MoCoꢀN/δ <
MoCoꢀN/δ MoCoꢀA/δ, showing that the better dispersion of MoCoꢀA/δ, which is in accordance with the result of XRD
<
active metal of catalysts with sulfate as assistant additives. The characterization.
existence of small amounts of βꢀCoMoO4 promotes the As shown in Fig.2 (B), the energy band gap decreases with the
synergies between Co and Mo, resulting in the formation of Coꢀ increase of the average particle size of molybdenum oxides in
MoꢀS active phase after sulfidation.
the catalysts. Besides, the energy band gaps of Mo species
change with the introduction of different cobalt salts. When
cobalt sulfide was used, the energy band gap of Mo species
increased obviously, indicating that the average particle size of
molybdenum oxides decreased and Mo species were distributed
well in the catalysts.
◆
★
2 3
δꢀAl O
βꢀCoMoO
4
★
◆
◆
◆
◆
◆
◆
MoCoꢀA/δ
MoCoꢀN/δ
◆
3.1.3 H
ꢀTPR characterization of the oxide CoMo catalysts
2
MoCoꢀD/δ
MoCoꢀS/δ
469
2 3
δꢀAl O
1
0
20 30 40 50 60 70 80
θ/degree
4
59
2
MoCoꢀS/δ
MoCoꢀA/δ
MoCoꢀN/δ
MoCoꢀD/δ
4
40
4
35
Fig. 1. XRD patterns of the series supports and catalysts with different cobalt
salts.
3
.1.2 UVꢀVis spectra of the oxide CoMo catalysts
2
00
400
600
800 1000
Temperature, ℃
(A)
35
(B)
3
2
2
1
1
0
5
0
5
0
5
0
MoCoꢀA/δ
MoCoꢀN/δ
MoCoꢀA/δ
2 2 3
Fig. 3. H -TPR profiles of MoCo/δ-Al O with different cobalt salts.
MoCoꢀN/δ
MoCoꢀD/δ
MoCoꢀS/δ
H ꢀTPR is applied to study the interaction between MoCo
2
MoCoꢀD/δ
MoCoꢀS/δ
species and the carrier by characterizing the reduction of MoCo
species on the catalyst surface by H . Fig.3 displays the H ꢀTPR
2
2
profiles of MoCo/δꢀAl O with different cobalt salts.
2
3
ꢀ
5
2
00 300 400 500 600 700 800
Wavelength,nm
2
3
4
5
6
The asꢀprepared catalysts showed two obvious reduction peaks
of H within the temperature range of 400–480 and 770–900
, as shown in Fig.3. However, there were no apparent
reduction peaks within the temperature scope of 600–630
which belong to the large MoO particles. The first strong
hv/ev
℃
2
℃
Fig. 2. (A) UV-vis DRS spectra, (B) plots of a 1/2 versus photon energy (hν) of
MoCo/δ with different cobalt salts.
℃
,
3
reduction peak is around 470
step of Mo reduction (Mo →HxMoO →Mo ) of highly
dispersed octahedral coordination Mo species. The other strong
℃, which is ascribed to the first
UVꢀvis DRS spectrum is usually applied to study the species of
MoO in CoMo catalysts. Fig.2 shows the UVꢀVis DRS spectra
6+
4+
3
and photoelectron spectroscopy diagrams of MoCo/δꢀAl O3
2
reduction peak is around 760
℃
, belonging to the deep
catalysts with loading of different kinds of cobalt.
Polymorphous crystalline aluminia based catalysts exhibit
adsorption peak between 200ꢀ400 nm which belongs to Mo
oxide. The adsorption peaks between 220ꢀ255 nm, 250ꢀ350 nm
belong to tetrahedron coordination Mo(T) species and low
4
+
0
reduction ( Mo + 2e–→Mo ) of polymeric octahedral,
25
tetrahedral and bulk crystalline MoO3. The temperature of
reduction peaks in the H ꢀTPR profiles directly reflect the
2
strength of the interaction between the active metal components
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Fig. 4. Raman spectra of the MoCo/δ catalysts with different cobalt salts.
and the carrier. The peak locations at low temperature of the asꢀ
prepared catalysts increase as the following order: MoCoꢀD/δ
<
ꢀ
1
After the loading of Co, the intensity of peak of 945 cm
MoCoꢀN/δ MoCoꢀA/δ MoCoꢀS/δ , which indicate that the
<
<
6
ꢀ
attributing to the vibration of Mo=O in Mo O , increases as
interaction between metal and carrier increasing as the above
order. Furthermore, compared with other catalysts, a strong
increase in the peak area in low temperature region and a
considerable decrease in the high reduction temperature of
tetrahedral Mo species are observed for MoCoꢀS/δ. These
phenomena mean an increase in the proportion of the dispersed
octahedral Mo species which are easy to be reduced as they are
promoted by cobalt sulfate, consequently it will probably favor
the formation of a mixed CoꢀMoꢀS phase.
7
24
the following order: MoCoꢀA/δ
<
MoCoꢀN/δ < MoCoꢀD/δ <
MoCoꢀS/δ, demonstrating that the Mo species of the MoCo
catalyst based on cobalt sulfate are easier to be deoxidized and
sulfided, which is in accordance with the results of H ꢀTPR.
Besides, the peak of 990 cm , which is ascribed to the bulk
MoO , are not found, meaning no aggregation of active metal.
The unobvious peak of 564 cm , which derives from the AlꢀO
stretching vibration accounting for the interaction between the
alumina carrier and the active metal, implys the weak metalꢀ
support interaction(MSI) over the δꢀAl O supported catalysts
2
ꢀ
1
3
ꢀ
1
3
.1.4 Raman characterization of the oxide MoCo catalysts
2
3
is beneficial for the reduction and sulfidation of active metal.
As shown in Fig.4, the Raman spectra of MoCo/δꢀAl O3
2
catalysts with different cobalt salts show main characteristic
3
.1.5 XPS characterization of the sulfide CoMo catalysts
ꢀ
1
peaks of 250
、
331
、564、839、945 and 980 cm . The peaks
ꢀ
1
ꢀ1
of 839 cm and 331 cm are attributed to the bending vibration
of Mo=O bond in the tetrahedron coordination MoO . The
peak of 945 cm , which is considered to be the signals of the
weak interaction between the metal and carrier, are relatively
easy to be deoxidized and sulfided in the presulfurization
process. Only the characteristic peak of the bending vibration of
2
ꢀ
(A)
(B)
4
(Ⅳ)
(
Ⅳ)
Mo 3d5/2
ꢀ
1 26
Mo 3d5/2
(
Ⅳ)
(Ⅳ)
Mo 3d3/2
Mo 3d3/2
(Ⅵ)
(
Ⅵ)
Mo 3d5/2
Mo 3d5/2
(Ⅴ)
(
Ⅴ)
Mo 3d5/2
(Ⅴ)
Mo 3d3/2
Mo 3d3/2
(Ⅴ)
(
Ⅵ)
Mo 3d5/2
(Ⅵ)
Mo 3d3/2
Mo 3d3/2
2ꢀ
S
2ꢀ
2
ꢀ
S
Mo=O bond, derived from the tetrahedron coordination MoO4
is found in the Raman spectra of Mo/δꢀAl O . The
,
2
3
6
ꢀ
characteristic peak of the vibration of Mo=O bond in Mo O24
7
appears after the introduction of Co into catalysts, indicating
that Co has a great influence on the atom state of Mo over the
catalyst surface and makes Mo better dispersion.
2
40
236
232
228
224
240
236
232
228
224
Binding energy, eV
Binding energy, eV
(C)
(D)
(
Ⅳ)
(Ⅳ)
Mo 3d5/2
Mo 3d5/2
(
Ⅳ)
(
Ⅳ)
Mo 3d3/2
Mo 3d3/2
(Ⅵ)
Mo 3d5/2
(
Ⅵ)
Mo 3d5/2
9
47
(Ⅴ)
(Ⅴ)
Mo 3d5/2
Mo 3d3/2
8
40
(
Ⅴ)
(Ⅵ)
Mo 3d3/2
Mo 3d3/2
(Ⅴ)
Mo 3d5/2
S
(
Ⅵ)
2ꢀ
Mo 3d3/2
S
2ꢀ
2
50
3
9
90
31
564
MoCoꢀS/δ
MoCoꢀN/δ
MoCoꢀD/δ
MoCoꢀA/δ
2
40
236
232
228
224
240
236
232
228
224
Binding energy, eV
Binding energy, eV
Fig. 5. Mo3d XPS spectra of the sulfided MoCo/δ catalysts with different cobalt
MoCo-N/δ;
Mo/δꢀAl
2
O
3
salts.
（
A
）
MoCo-A/δ;
（
B
）
（
C
）
MoCo-D/δ
（D
）
MoCo-S/δ.
2
00 400 600 800 1000 1200 1400
ꢀ1
Raman shift, cm
Table 1. XPS characterization results of the series of MoCo sulfided catalysts.
4+
5+
6+
Mo
Mo
Mo
a
b
Catalysts
ar. %
ar.%
ar. %
ar. %
ar.%
ar.%
S
Mo
(228.9 eV)
(232.0 eV)
(230.5 eV)
(233.6 eV)
(232.5 eV)
(235.6 eV)
MoCoꢀA/δ
MoCoꢀN/δ
MoCoꢀD/δ
36
38
39
41
24
25
26
27
5
3
2
2
3
2
2
2
20
19
18
17
13
13
12
11
60
63
65
68
MoCoꢀS/δ
a
Note: ar. % means the area percent of XPS peak.
b
4+
4+
5+
6+
SMo= Mosulfidation = Mo /(Mo +Mo +Mo ).
4
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XPS is a very useful characterization method to obtain the type MoCoꢀS/δ. The catalyst with cobalt acetate as cobalt resource
and content of the active components on the surface of the gives the lowest HDS activity (95.1%). However, the catalyst
sulfided HDS catalysts, and it is always used to analyze the with cobalt sulfate as cobalt salts displays the highest
sulfidation degree of Mo based catalysts. Fig.5 shows the Mo3d desulfurization rate (97.5%).
XPS spectra peak fitting results of the sulfided MoCo/δ According to the results of XRD and UVꢀvis spectra, the
catalysts with different cobalt salts. The XPS analysis results catalyst with cobalt sulfate as cobalt resource shows moderate
proceeded by the XPSPEAK 4.1 software are shown in Table 1. content of βꢀCoMoO , and the active metal phases present
4
The standards for the fitting are as follow: the binding energies smaller particle size and better dispersion when compared with
4
+
of Mo3d5/2 and Mo3d3/2 of Mo (MoS ) are 228.9±0.1 eV and other cobalt resources. The results of Raman confirm that the
2
5+
2
2
2
31.7±0.1 eV, respectively; while those for Mo (MoS O ) are surface of the catalyst with cobalt sulfate as cobalt salts
x y
30.2±0.1 eV and 233.5±0.1 eV, and for Mo (MoO ) are possesses more six coordination twoꢀdimensional polymer
32.5±0.1 eV and 235.8±0.1 eV; whereas the binding energy Mo O
of S2s is 226.3±0.1 eV. The sulfidation degree of the oxide characterization shows that an increase in the proportion of the
6
+
3
27
6ꢀ
which is easier to be deoxidized. Besides, H ꢀTPR
2
7
24
28
4+
Mo species, Mosulfidation, is calculated by Mosulfidation= Mo /( dispersed octahedral Mo species which are easy to be reduced
4
+
5+
6+
Mo +Mo +Mo ) as listed in Table 1. The sulfidation degree when promoted by cobalt sulfate, indicating that it probably
of Mo species increases in the following order: MoCoꢀA/δ favors the formation of the mixed CoꢀMoꢀS phases. XPS results
MoCoꢀN/δ MoCoꢀD/δ MoCoꢀS/δ. MoCoꢀA/δ catalyst also demonstrate the higher sulfurization degree of MoCoꢀS/δ
shows the lowest sulfidation degree (60%) of Mo species, while catalyst. It has been reported that the catalysts with cobalt
<
<
<
29
MoCoꢀS/δ catalyst exhibits the highest degree (68%). The XPS acetate and acetyl acetone cobalt as cobalt salts showed better
results demonstrate that Mo species over MoCoꢀS/δ catalyst are HDS activity, which was a little different from our results. On
easy to be sulfided compared with other catalysts. Therefore, one hand, the possible reason is the different methods of the
according to XPS analysis results, when the cobalt sulfate is metal loading. On the other hand, the catalyst support used in
used, Mo species can be dispersed and sulfided well, which is this research is different with the supports reported. Through
in consistent with the results of H ꢀTPR.
the analysis of characterization and evaluation of activity, it can
be clearly seen that the HDS activity over MoCoꢀS/δ catalyst is
the highest among this series catalysts, demonstrating that the
introduction of cobalt sulfate can apparently promote the HDS
performance of the MoCo/δ catalyst.
2
3
.2 Evaluation of HDS reactivity of FCC diesel
4
.
Conclusions
In this research, CoMo series catalysts were prepared by using
lowꢀcost δꢀAl O3 as support and different cobalt salts as
2
promoter. The series of supported CoMo catalysts for HDS
were characterized by UVꢀVis, Raman, XRD, TPR, and XPS.
The effects of different metal cobalt salts on HDS activity were
explored systematically. This research provides a novel
MoCo/δꢀAl O catalysts promoted by cobalt sulfate that can be
2
3
used to the HDS reaction with high performance.
Different cobalt salts showed significant influences on the HDS
activities of catalysts. As for the catalysts with δꢀAl O as
Fig. 6. HDS performances of the sulfided CoMo/δ catalysts with different cobalt
salts.
2
3
support, the HDS activities of various catalysts increased in the
following order: MoCoꢀA/δ MoCoꢀN/δ MoCoꢀD/δ MoCoꢀ
<
<
<
Fig.6 shows the HDS reactivity results of the catalysts with S/δ. The catalyst with cobalt acetate as cobalt resource
different cobalt salts over δꢀAl O3 carriers. Different cobalt exhibited the lowest HDS efficiency (95.1%) and the catalyst
2
salts display significant influence on the hydrogenation activity with cobalt sulfate displayed the highest desulfurization degree
of the catalysts. As for the catalysts with δꢀAl O as support, (97.5%). These characterization results demonstrated that
2
3
the hydrogenation activities of the catalysts increase in the taking cobalt sulfate as promoter on the supported MoS2
following order: MoCoꢀA/δ
<
MoCoꢀN/δ
<
MoCoꢀD/δ
<
systems enabled to obtain a higher sulfidation degree (68%)
This journal is © The Royal Society of Chemistry 2013
J. Name., 2013, 00, 1-3 | 5

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Page 6 of 7
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ARTICLE
5RA17414G
DOI: 10.1039Jo/Curnal Name
compared to the other cobalt promoters. These catalytic results
could be ascribed to that the introduction of different cobalt
salts decreased the MSI between metal and support, and led to 20 J.L. Roustan, Y. Lijour, B.A. Morrow, Inorg. Chem., 1987, 26, 2509ꢀ
the formation of easily reduced Mo species, which were the
2516.
high active precursors to form more active sites that could 21 A.D. Gandubert, E. Krebs, C. Legens, D. Costa, G. Guillaume, P.
enhance HDS activity of the catalysts. Moreover, Mo species
Raybaud, Catal. Today, 2008, 130, 149ꢀ159.
could be dispersed and sulfided well when the different cobalt 22 Y. Saih, M. Nagata, T. Funamoto, Y. Masuyama, K. Segawa, Appl.
salts were used. Therefore, it can be concluded that the
Catal. A, 2005, 295, 11ꢀ22.
outstanding promoter effect endowed the MoCoꢀS/δ catalyst to 23 J. Ramiréz, P. Castillo, L. Cedefio, R. Cuevas, M. Castillo, J. Palacios,
be a promising catalyst for FCC diesel hydrotreating.
A.L. Agudo, Appl. Catal. A, 1995, 132, 317ꢀ334.
2
2
2
2
2
2
4 J. Ojeda, N. Escalona, J.M. Palacios, M. Yates, J.L.G. Fierro, A.L.
Agudo, F.J.G. Llambias, Appl. Catal. A, 2008, 350, 6ꢀ15.
Acknowledgement
5 S. Damyanova, A. Spojakina, K. Jiratova, Appl. Catal. A, 1995, 125
57ꢀ269.
6 E. Payen, J. Grimblot, S. Kasztelan, J. Phys. Chem., 1987, 91, 6642ꢀ
648.
,
This work was supported by National Natural Science
Foundation of China (No. 21276277 and U1463207), CNOOC
Huizhou Refinery Branch(HL00FW2012ꢀ0196), National Basic
Research Program of China (Grant No. 2012CB215001 &
2
6
7 J. Muijsers, T. Weber, R. Vanhardeveld, H.W. Zandbergen, J.
Niemantsverdriet, J. Catal., 1995, 157, 698ꢀ705.
2
012CB215002), and CNPC major project.
8 T. Fujikawa, M. Kato, T. Ebihara, K. Hagiwara, J. Jpn. Petrol. Inst.,
Notes and References
2
005, 48, 114ꢀ120.
9 D. Laurenti, B. PhungꢀNgoc, C. Roukoss, E. Devers, K. Marchand,
L.Massin, L. Lemaitre, C. Legens, Q. AnneꢀAgathe, M. Vrinat, J.
Catal., 2013, 297, 165ꢀ175.
1
2
3
4
I. Bezverkhyy, P. Afanasiev, M. Lacroix, J. Catal., 2005, 230, 133ꢀ139.
V. C. Srivastava, RSC Adv., 2012, , 759ꢀ783.
2
S. Eijsbouts, Appl. Catal. A, 1997, 158, 53ꢀ92.
Y. Okamoto, K. Hioka, K. Arakawa, T. Fujikawa, T. Ebihara, T.
Kubota, J. Catal., 2009, 268, 49ꢀ59.
5
6
D. Whitehurst, T. Isoda, I. Mochida, Adv. Catal., 1998, 42, 345ꢀ471.
H. TopsΦe, B.S. Clausen, R. Candia, C. Wivel, S. Mørup, J. Catal.,
1
981, 68, 433ꢀ452.
7
8
9
1
J.A.R. van Veen, E. Gerkema, A.M. van Der Kraan, P.A.J.M. Hendriks,
H. Beens, J. Catal., 1992, 133, 112ꢀ123.
H. Farag, D.D. Whitehurst, K. Sakanishi, I. Mochida, Catal. Today,
1
999, 50, 9ꢀ17.
Y. Okamoto, S. Ishihara, M. Kawano, M. Satoh, T. Kubota, J. Catal.,
003, 217, 12ꢀ22.
2
0 S.M.A. Bouwens, F.B.M. van Zon, M.P. van Dijk, A.M. van der
Kraan, V.H.J. de Beer, J.A.R. van Veen, D.C. Koningsberger, J.
Catal., 1994, 146, 375ꢀ393.
1
1 Y. Okamoto, A. Kato, Usman, N. Rinaldi, T. Fujikawa, H. Koshika, I.
Hiromitsu, T. Kubota, J. Catal., 2009, 265, 216ꢀ228.
1
1
1
2 Y. Okamoto, J. Catal., 2008, 132, 9ꢀ17.
3 H. Topsøe, B.S. Clausen, Appl. Catal., 1986, 25, 273ꢀ293.
4 P. Raybaud, J. Hafner, G. Kresse, S. Kasztelan, H. Toulhoat, J. Catal.,
2
000, 190, 128ꢀ143.
1
1
5 L.S. Byskov, B. Hammer, J.K. Norskov, B.S. Clausen, H. Topsoe,
Catal. Lett., 1997, 47, 177ꢀ182.
6 A. Travert, H. Nakamura, R.A. van Santen, S. Cristol, J.F. Paul, E.
Payen, J. Am. Chem. Soc., 2002, 124, 7084ꢀ7095.
1
1
7 H. Schweiger, P. Raybaud, H. Toulhoat, J. Catal., 2002, 212, 33ꢀ38.
8 I. Bezverkhyy, P. Afanasiev, M. Lacroix, J. Catal., 2005, 230, 133ꢀ
1
39.
1
9 Y. Okamoto, K. Ochiai, M. Kawano, K. Kobayashi, T. Kubota, Appl.
Catal. A, 2002, 226, 115ꢀ127.
6
| J. Name., 2012, 00, 1-3
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View Article Online
DOI: 10.1039/C5RA17414G
GRAPHICAL ABSTRACT
2 3
In this paper, the supported MoCo/δꢀAl O catalysts promoted by different organic
and inorganic cobalt salts were synthesized successfully by an incipientꢀwetness
impregnation method. The active metalꢀsupport interaction(MSI) were adjusted by
incorporating cobalt nitrate, cobalt sulfate, cobalt acetate, cobalt diacetylmethane into
3 2 3
the framework of MoO /Al O , which could provide suitable MSI for ultra deep HDS
to meet the high quality specifications of diesel. The HDS activities of various
catalysts increased in the following order: MoCoꢀA/δ< MoCoꢀN/δ< MoCoꢀD/δ<
MoCoꢀS/δ. As a result, the outstanding promoter effect endowed MoCoꢀS/δ to be a
promising catalyst for FCC diesel hydroupgrading.