Sol–Gel Autocombustion Combined Carbothermal Synthesis of Iron-Based Catalysts for the Fischer–Tropsch Reaction

Article abstract of DOI:10.1002/cctc.201701424

A new combined method of sol–gel autocombustion with carbothermal reduction has been developed to synthesize Fe-based Fischer–Tropsch synthesis (FTS) catalysts. The effect of the glucose content on the structure and texture of the Fe phase is investigated. The glucose is employed as a reducing and carburizing agent to control the phase transformation of the Fe precursors. The reducibility of the synthesized iron oxide increases with the increase of the proportion of glucose. Meanwhile, iron oxide is converted completely into iron carbide in the presence of abundant glucose. The addition of glucose to the precursor is conducive to construct active sites before the FTS reaction. However, excess glucose results in carbon deposition and a poor FTS performance. Iron carbide also could be synthesized by this new method and will be applied directly to the FTS reaction in further research.

Full text of DOI:10.1002/cctc.201701424

Accepted Article
Title: Sol-gel autocombustion combined carbothermal synthesis of iron-
based catalysts for Fischer-Tropsch reaction
Authors: Yingying Xue, Yongbiao Zhai, Zheng Chen, Juan Zhang,
Jiaqiang Sun, Jiangang Chen, Abbas Mohamed, and Yilong
Chen
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ChemCatChem
10.1002/cctc.201701424
FULL PAPER
Sol-gel autocombustion combined carbothermal synthesis of
iron-based catalysts for Fischer-Tropsch reaction
[a, b]
[c]
[a, b]
[a]
[a]
[a,
Yingying Xue,
Yongbiao Zhai, Zheng Chen, Juan Zhang, Jiaqiang Sun, Mohamed Abbas,
d]
[e]
[a]
Yilong Chen, and Jiangang Chen*
Abstract: A novel combined method of sol-gel autocombustion with
carbothermal reduction has been developed to synthesize Fe-based
Fischer-Tropsch synthesis (FTS) catalysts. The effect of glucose
content on the structure and texture of Fe phase is investigated. The
glucose is employed as reducing and carburizing agent, which
controls the phase transformation of Fe precursors. The reducibility
of synthesized iron oxide increases as the enhancement of glucose
proportion. Meanwhile, the iron oxide is completely converted to iron
carbide in the case of abundant glucose. Adding glucose in the
precursor is conducive to construct the active site prior to the FTS
reaction. However, the excess glucose results in the carbon
deposition and poor FTS performance. Iron carbide also could be
synthesized by this novel method and is directly applied to FTS
reaction in further research.
(2) Liquid organic compounds, such as hydrocarbons, alcohols
[
6]
or aldehydes. (3)Solid carbon source, such as carbon powder,
[
7]
sugars, citric acid or polyethylene glycol. All these activation
steps are aimed at constructing the active Fe phase (α-Fe or
iron carbide). In the (1) and (2) process, the precursors are iron
oxide phase. They need further calcination again to turn into the
active phase. In the (3) process, carbon source is mixed with the
raw materials in the initial stage of preparation. It needs
calcination only once to achieve the active phase under the
moderate carbon content. Therefore, this carbothermal reduction
method is environmentally friendly in terms of energy
conservation.
The emergence of new preparation routes renders the academic
research diverse. The sol-gel autocombustion technique has
[8]
been developed for the synthesis of metals and metal alloys.
However, few researches thus far have published the combined
methods of sol-gel autocombustion synthesis with carbothermal
process applying in Fe-based FTS catalyst preparation.
Noritatsu et al. reported the copper, cobalt and iron catalysts
using surface impregnation combustion and sol-gel
Introduction
Fischer-Tropsch synthesis (FTS) is an sustainable technology to
produce hydrocarbons. FTS products are environmentally
friendly, meeting the global requirement for transportation fuels
and specific high value-added chemicals. The accepted active
phase of FTS catalysts are VIII group transition metals (Co, Fe,
Ru and Ni). They can activate and bond with adsorbate because
of the peculiar incompletely filled
catalysts are easily available and industrially applied in FT
technology, albeit with reported actual active phase that need to
be further confirmed.
Generally, the iron oxides (Fe
fresh catalysts and they must be subjected to an activation step
prior to FT reaction. The activation process undertakes the
transformation of iron oxides to the low state iron oxides,
[9]
autocombustion methods. This novel method ensures raw
materials mixing at the molecular level in the form of solution. A
large amount of gas released during the combustion process
makes the products porous with high specific surface area
[
1]
(
SSA). This specific feature is beneficial for gas diffusion and
[
2]
d
orbitals.
Iron-based
catalytic reaction. Note that the entire combustion process
terminates in a few minutes without external energy. Moreover,
the original reactants are cheap and low toxic. The as-
synthesized products are fine and homogeneous nano-sized
[
3]
2
O
3
, Fe
3
O
4
, FeO) are prepared as
[10]
particles. Then we combine carbothermal reduction method to
control the phase of iron precursors. The combined method
overcomes the drawback of solid state reaction, resulting in the
homogenous nanoparticles.
Consequently, we adopt the novel combined method to
synthesize iron catalysts and evaluate their FTS performance.
[
3a, 3c, 4]
metallic iron or iron carbides.
measures summarized as follows: (1) Reducing gas, such as H
CO, syngas, low hydrocarbons or the mixture of one of them.
There are several activation
2
[
,
5]
We obtain
autocombustion prior to carbothermal reaction. The glucose
acted as reductant dramatically affects the combustion
process and the phase composition. Urea is employed as a fuel
and a foamer due to its low price, availability, more active –NH
a
homogeneous precursor via the sol-gel
a
[
a]
Y.-Y. Xue, Y.-B. Zhai, J. Zhang, Z. Chen, J.-Q. Sun, M. Abbas, Prof.
J.-G. Chen
2
Institute of Coal Chemistry Department
Chinese Academy of Sciences
Taiyuan, 030001, China
than –OH group. The combustion products swell several times
larger than the original volume, generating porous, fine, foamy
and fragile nanoparticles. Characterization results indicate that
the glucose dramatically influence the phase, texture and
reduction behavior of as-synthesized catalyst. The iron carbide
phase is obtained by adding optimal amount of glucose. The
FTS activity first enhances and then decreases with the increase
of glucose content. This method can also provide a novel way
for designing iron carbide nanoparticles.
E-mail: chenjg@sxicc.ac.cn.
[b]
[c]
[d]
[e]
Y.-Y. Xue, Z. Chen
University of Chinese Academy of Sciences
Beijing, 100049, China
Y.-B. Zhai
College of Electronic Science and Technology, Shenzhen university
Shenzhen, 518060, China.
M. Abbas
Ceramics Department, National Research Centre
El‑Bohouth Str, 12622 Cairo, Egypt
Y.-L. Chen
State Key Laboratory of Biomass Thermal Chemistry Technology
Wuhan, Hubei, 430223, China.
Results and Discussion
Supporting information for this article is given via a link at the end of the
document.
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ChemCatChem
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FULL PAPER
microstructure on the surface layer, Fe 2p XPS spectra of all the
as-synthesized catalysts are presented in Figure 2. It is clearly
observed that the 1.5G catalyst show significantly different Fe 2p
peaks compared to other catalysts. The XPS peaks with binding
energy at 710.8 eV and 724.6 eV are assigned to Fe 2p3/2 and
3
+
2
p
1/2, respectively, indicating the Fe species in Fe
2
O
3
and
[
12]
3 4
Fe O .
A different peak at 707.5 eV is detected in the 1.5G
catalyst, which is ascribed to the iron carbide species.
result is in agreement with the XRD characterizations.
[13]
This
Figure 1. XRD patterns of as-synthesized catalysts : (a) 0.3G; (b) 0.5G; (c)
0.9G; (d) 1.2G; (e) 1.5G.
Figure 2. Fe 2p XPS spectra of the as-synthesized catalysts.
Figure 3. FESEM images of as-synthesized catalysts. (a) 0.3G (b) 0.5G (c)
The XRD patterns of as-synthesized iron catalysts are illustrated
in Figure 1. Sample a has good crystallinity and the detected
0.9G (d) 1.2G (e) 1.5G.
diffraction peaks are ascribed to Fe
3 4
O phase (JCPDS No.19-
0
629) and Fe phase (JCPDS No.39-1346). The diffraction
2 3
O
peaks of these two phases almost overlap entirely except the
position at 2=57.0 and 62.6. According to the enlarged graph
in the upper right, the diffraction peaks split in these two
positions, implying that Fe
a. No characteristic peaks of Fe
the samples. The average crystalline size of Fe
calculated from Scherrer equation is 33.8, 25.6, 23.7, 28.2 nm
and N/A (it denotes not applicable because there is no Fe
crystalline phase in sample e ), respectively. With the increase
of glucose content, Fe phase and Fe phase are gradually
2
O
3
crystalline phase exists in sample
phase appear in the rest of
(311)
2
O
3
3
O
4
3
O
4
3
O
4
2
O
3
Figure 4. FESEM-EDS mapping analysis of 0.5G catalyst.
The effect of glucose content on the surface morphology is
shown in Figure 3. The first four samples (a, b, c, d) consist of
porous, interconnected nanoparticles, which can be attributed to
the rapid combustion course accompanying with a large amount
of gas released from the reaction. Clearly, sample e presents a
bulk structure, which is significantly different from other samples.
Nevertheless, The bulk structure is similar to the slab with a thickness of 1 μm.
reduced to FeO phase and Fe phase. On the other hand, the
diffraction peaks are dominated by metallic Fe as the increase of
reductant generated by glucose in the carbothermal process.
However, sample e (1.5G) yields peaks mainly characteristic of
C (JCPDS No.35-0772). It has been reported that
3
C is active in FTS reaction and this phase is
5 2
oxidized less rapidly than Hägg carbide -Fe C .
cementite Fe
cementite Fe
3
[
11]
these two reported iron carbides were synthesized by gas
carbonization (CO). Our obtained cementite Fe C is different
from the published literature. In order to verify the FTS
performance of our prepared cementite Fe C and Hägg carbide
-Fe , we prepared Hägg carbide -Fe by carbonizing sol-
There are some small particles attached to the broken slabs. As
demonstrated in XRD patterns, sample e is dominated by iron
carbide phase. While the other four samples are the mixture of
iron oxide and metallic Fe. During the combustion process, the
system swelled quickly and became a porous, honeycomb
3
3

5
C
2
5 2
C
gel autocombustion precursors in CO at 300C for 12 h. The
phase identification and their FTS performance are presented in
Figure S1 and Table S1. To gain further insight into the
structure.
A large amount of gas produced during the
combustion process would prevent the aggregation of particles.
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ChemCatChem
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two obvious peaks in the TPR profile. The first peak centered at
380C is assigned to Fe
2 3 3 4
O to Fe O . And the second broad
peak located at 400-680C corresponds to the reduction of
[14]
Fe
3
O
4
to metallic Fe.
Samples prepared by sol-gel
autocombustion with carbothermal reduction method present a
wide peak at 300-700C except sample 1.5G. Closely
observations show that an exceptionally weak peak (see
rectangular frame) is detected in 0.3G sample. This weak peak
disappears as the increase of glucose content in the catalyst. It
2 3 3 4
is attributed to the reduction of Fe O to Fe O . From the
convolution of the TPR peaks, it is found that the amount of
hydrogen consumption is highest in the co-precipitation catalyst.
Among the catalysts prepared by the novel combustion method,
the amount of hydrogen consumption show a decline trend with
the increase of the glucose content. This evidently indicates that
2 3 3 4
Fe O phase transforms to Fe O , FeO and metallic Fe by
glucose, which perfectly matches with the XRD results. In the
combustion process, the carbon produced from glucose acted
as a reductant partly and the other part reacted with oxygen to
Scheme 1. Flowchart of the catalyst preparation process by the novel method.
It is noteworthy that all elements are well distributed in 0.5G
catalyst, as demonstrated by EDS mapping (Figure 4). And in
the 1.5G/K catalyst, the potassium is uniformly dispersed, as
confirmed by EDS mapping (Figure S2). The phenomenon
occurred during the preparation process and the flowchart of the
preparation process are illustrated in scheme 1. It is estimated
that the final volume is ten times larger than the original system
generate carbon dioxide. Fe
Fe by carbon in advance. Therefore, no hydrogen
consumption peak of Fe to Fe is detected in 0.5G, 0.9G
and 1.2G samples. Moreover, with the increase of glucose, the
reduction peak of Fe to metallic Fe shifts into lower
2 3
O phase was nearly reduced to
3
O
4
2
O
3
3 4
O
3
O
4
temperature. These findings are consistent with XRD results that
the addition of glucose accelerates the reduction of iron oxide.
Notably, the reduction behavior of sample 1.5G is dramatically
different from others. It is identified by XRD profiles that the main
phase of 1.5G sample is iron carbide. The hydrogen
consumption peak centered at 300C may be the decomposition
of iron carbide or the hydrogenation of residual carbon. It need
further confirmation to elucidate the peak assignment.
(
see the optical image in Figure S3). In addition, the
decomposition of glucose is endothermic and it would reduce
the dispersant effect. It is consistent with the SSA results
displayed in Table 1. The SSA results show a decline trend
because of the unnecessary accumulation of carbon in the
system. As shown in Table 1, the carbon content of as-
synthesized catalysts arises from 3.2% to 20.1% with the
increase of glucose content.
Table 1. SSA and carbon residue of as-synthesized catalysts.
Catalyst
0.3G
0.5G
0.9G
1.2G
1.5G
2
SSA(m /g)
84.6
3.0
75.0
3.8
49.7
5.7
21.3
9.0
5.64
19
Pore diameter(nm)
3
Pore volume(cm /g)
0.016
3.2
0.018
5.7
0.025
11
0.023
15
0.020
20
C%
Figure 6. CO-TPD profiles of the as-synthesized catalysts with different
glucose content.
The CO-TPD profiles of catalysts reduced with hydrogen (0.3G,
0.5G, 0.9G, 1.2G) and untreated iron carbide (1.5G) are
illustrated in Figure 6. There is a weak and broad desorption
peak centered at 450C in hydrogen reduced samples. It is
[
15]
ascribed to strong CO adsorption reported in literature.
The
strong CO adsorption means dissociative adsorption of CO,
recombining to desorb at this temperature. This recombination
may be the surface adsorbed carbon and oxygen. Compared
with hydrogen reduced samples, the desorption peak shifts
toward higher temperature (550C) in 1.5G sample, which is
ascribed to the unique active site. Iron oxides transform into
Figure 5. TPR profiles of the as-synthesized catalysts. Effect of glucose
content and preparation method.
The reduction behavior of fresh catalysts, including the
reference sample synthesized by the traditional co-precipitation
method, are displayed in Figure 5. For the reference, there are
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ChemCatChem
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FULL PAPER
metallic iron (it has been confirmed by XRD results in Figure S4)
by hydrogen reduction and subsequent CO adsorption starts on
such active sites. The difference between metallic iron and iron
accumulation. It is generally known that iron oxide (Fe
3 4
O ) is
active for water gas shift reaction. Therefore, it is necessary that
[
5e]
the iron oxide catalysts require a reduction process
prior to
carbide results in the unique CO adsorption behavior. In addition, FTS reaction. As shown in Table 2, a higher CO conversion and
another sharp peak is detected at higher temperature (700C)
overlapping with the front peak in 1.5G sample, which could
correspond to the reaction of bulk adsorbed carbon and oxygen.
4
lower selectivity of CH are obtained in 0.5G catalyst. The
glucose additive serves two purposes: (1) as a reductant; (2) as
a carbon source to form iron carbide in advance. It is generally
recognized that iron carbide is the actual active phase under the
FTS condition. Prior to the reaction, Fe reacts with C atom
generated from the decomposition of glucose to form iron
carbide phase. It is inevitable that oversupplied glucose results
in carbon deposition and the blockage of active sites. The
potassium (100 g Fe/2 g K) was adopted to improve the
performance of 1.5G catalyst. The selectivity of CH
4
is
suppressed and the olefin/paraffin ratio is enhanced dramatically.
Meanwhile, the percent of heavy hydrocarbons is the highest in
all the catalyst. Actually, potassium is a donor electronic
promoter in the catalyst system. The electron density of metal
increases after the potassium is introduced. Then the metal-
carbon σ bond is weakened and the π back-donation bond is
strengthened. The π back-donation effect stabilizes adsorbate-
metal complex and weakens the internal C-O bond whereas the
Figure 7. (a) CO conversion and (b) product distribution of 0.5G catalyst with
time on stream.
Table 2. The FTS performance of as-synthesized catalysts.
Catalyst
XCO/%
S
CO2/%
Hydrocarbon distribution (C% mol)
C
C
2
-
4
CH -C
4
C
2
4
C
5
-C11
C
5+
O/P
[
[
a]
a]
0
0
0
1
1
1
1
.3G
.5G
.9G
.2G
.5G
.5G
.5G/K
33.4
42.9
31.9
24.2
29.6
19.8
37.3
27.6
9.3
10.6
8.4
33.8
44.4
62.6
58.0
55.7
51.2
23.0
34.7
41.3
37.5
26.0
26.1
26.1
27.3
63.3
41.6
55.6
47.2
26.5
27.9
26.6
28.4
67.2
54.2
1.01
[
16]
σ
bond destabilizes it.
Hence, the potassium promoter
13.8
12.1
9.9
0.79
1.04
0.60
1.11
1.60
2.64
0.96
enhances CO dissociation and improves the FTS performance.
The 0.5G catalyst exhibits the highest CO conversion as high as
[
[
a]
a]
10.9
14.1
17.7
20.4
9.8
42.9% and comparatively low methane selectivity. Compared
with the synthesized catalysts by the novel method, the
conventional co-precipitation catalyst shows the medium FTS
activity. There is a common feature of all synthesized catalysts
that the FT products are mainly light hydrocarbons, which is a
characteristic of most precipitated Fe catalysts. Our obtained
catalysts exhibit higher liquid hydrocarbon productivity and low
methane selectivity under mild reaction conditions. The stability
with the reaction time of 0.5G catalyst is illustrated in Figure 7a.
The CO conversion still maintain at about 40% within 220 h
running, which indicates that the catalyst displays excellent
stability. The product distribution is summarized in Figure 7b.
[
[
[
[
a]
b]
b]
a]
13.9
13.5
14.6
10.6
co-
precipitation
11.1
[
a]Reduction condition: 400 °C, in hydrogen for 6 h, FTS performance: 240°C
-
1
(
P : 20 bar, GHSV : 3000 h , H
2
/CO=2). [b]Directly applied in FTS reaction at
The selectivity of CH
remain unchanged. The conversion of CO to CO
rising from 7% to 16% within the 72 h running and then kept at
this level.
4
(9%), C
2
-C
4
(45%), C
5
-C11 (38%) is almost
is observed
2
90°C without reduction procedure.
2
The synthesized Fe-based catalysts were applied in FTS
reaction to study the effect of glucose content on the catalytic
performance. Table 2 shows the FTS performance of catalysts
prepared with the varied glucose content. The increasing
glucose content first enhances the CO conversion. However, it is
found that further increasing the glucose content lowers the FTS Conclusions
activity. The selectivity of CH is suppressed first and then
4
enhanced by the addition of glucose. Moreover, all the catalysts
without reduction were also applied in FTS. The detailed FTS
A series of iron-based FTS catalysts have been successfully
synthesized by novel combined method of sol-gel
a
[
7b]
performance can be found in Table S2. Previous reports have
demonstrated that the selectivity of CO is up to 50% when the
autocombustion with carbothermal reduction. The glucose
employed as reducing and carburizing agent plays a crucial role
on phase, morphology, texture and reduction behavior as well as
catalytic performance. The glucose decomposes into carbon for
constructing iron carbide from iron oxide prior to FTS reaction.
With the increase of the glucose content, both the reducibility of
the catalyst and the residual carbon content are enhanced. Due
to the carbon accumulation in the catalysts, the SSA show a
decline trend. The 0.5G catalyst exhibites better FTS
performance with the highest CO conversion and relatively low
2
iron oxide catalyst is directly applied in FTS reaction. As
predicated, the iron oxide catalysts (0.3G, 0.5G, 0.9G, 1.2G)
show lower activity and higher selectivity of CO even at high
2
reaction temperature (290C) (Table S2) compared with the pre-
reduced catalysts. This can be attributed to the iron oxide phase
in these catalysts, which is demonstrated by XRD patterns. The
1.5G catalyst is mainly composed of Fe
3
C, which exhibits low
activity and high methane selectivity because of excess carbon
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ChemCatChem
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FULL PAPER
methane selectivity. We also adopt this novel method to
synthesize iron carbide and directly apply for FTS reaction
without the reduction process. The potassium promoter
dramatically improves the FTS performance of synthesized iron
carbide catalyst. This makes the directly synthesized iron
carbide a promising candidate for FTS catalyst.
CO-temperature programmed desorption(CO-TPD) experiments were
operated on an own-manufactured reactor along with pulse injection. The
exhaust was recorded by a quadruple mass spectrometer that linked in
outlet of the reactor. 100 mg reduced catalyst was put in the flat-
temperature zone of the reactor and was purged with helium at 400 C
for 1 h with the heating rate of 5C/min. Until the reactor cooled down to
50C in helium flow, then the pulse adsorption started immediately with
5%CO/He. The terminate of adsorption was depended on MS signal of
CO. Continuously purging with helium for 30 min until the MS baseline
leveled off. Afterwards, the temperature was heated up to 800C with the
rate of 15C/min.
Experimental Section
Catalyst synthesis
FTS performance
The carbothermal precursors were synthesized by
autocombustion method. Fe(NO ·9H O (5.14 g, 98.5%, Sinopharm
chemical reagent Co., Ltd) as a iron source, anhydrous glucose (0.75 g,
9%, Sinopharm chemical reagent Co., Ltd) as a reductant and carbon
a
sol-gel
The FTS performance of iron catalysts was carried out in a fixed-bed
reactor. The reaction tube was stainless steel with an inner diameter of
3
)
3
2
10 mm. The catalyst powder was tabletted in the absence of any binder
9
and then grinded, sieved to obtain the required size. 1 mL 60-80 mesh
catalyst mixed with 1 mL 60-80 mesh quartz sand were placed in the
isothermal region of the tube. Both ends of the catalyst bed were filled
with quartz sand in order to support the catalyst and avoid hot spots.
Prior to reaction, the catalyst was reduced in-situ in hydrogen at 400°C
for 6 h under atmospheric pressure. The FTS reaction conditions were
source, urea (3.41 g, 99%, Sinopharm chemical reagent Co., Ltd) as a
fuel were mixed in aqueous solution. The solution with vigorous stirring
was heated in water bath at 80 °C. After evaporating water gradually, a
yellow “urea-gelation” product produced. The “urea-gelation” is
immediately transferred to an air dry oven preheated to 120 C. Then the
gelation in the beaker swelled quickly and subsequently started burning
for a few minutes. Meantime, the beaker was almost burned red, which
seemed like a flaming beaker. The products swelled ten times larger than
the original volume. Subsequently, the obtained precursors were loaded
in ceramic boats in a tubular furnace, heating in flowing argon at 600 C
for 3 h with the rate of 5C / min. During the preparation process, the
dosage of raw materials were listed as follows. The molar ratio of glucose
to iron nitrate was 0.3, 0.5, 0.9, 1.2 and 1.5, marked as 0.3G, 0.5G, 0.9G,
-
1
designed at 240°C, 20 bar, 3000 h and the feed gas composition is
/CO = 2. The flow rate of gas was controlled precisely by a Brooks
instrument. The exit gas CO, H CO and CH were periodically
analyzed on line by two gas chromatography (GC) equipped with TCD
detectors and Porapak stainless packed columns. The light
hydrocarbons were analyzed on line by GC equipped with one FID
detector and a Al capillary column (HP-PLOT). The condensable
H
2
2
,
2
4
Q
2 3
O
products were collected by a hot trap and a cold trap. During the FTS
process, the carbon balance and mass balance were kept within the
range of 100±5%.
1
.2G, 1.5G. For comparison, the reference Fe catalyst was prepared with
the precipitant (i.e., NH HCO , 3 times the molar amount of iron nitrate,
9%, Sinopharm chemical reagent Co., Ltd) at 50C by conventional co-
4
3
9
precipitation method.
Acknowledgements
Characterization
This research is supported by the National Natural Science
Foundation of China (Grant No.21673272, No.21373254 and
No.21503256). The support from the State Key Laboratory of
Biomass Thermal Chemistry Technology (Wuhan) is also
appreciated.
X-ray diffraction(XRD) spectrum were obtained on
diffractometer with Cu Kα radiation running at 30 mA and 40 Kv. The
XRD analysis was used to identify crystalline phase and calculate
crystallite size. We excluded the instrumental broadening using
a D/max-RA
a
reference material (300C annealing silicon powder) when Scherrer
equation was employed to calculate crystallite size.
Keywords: carbothermal • Fischer-Tropsch synthesis • iron
carbide • sol-gel autocombustion
Field emission scanning electron microscopy (FESEM) measurements
equipped with an EDS detector were carried out on the instrument JSM-
7
001F (Japan), which were used for surface morphology and chemical
[1]
2]
C. K. Roferdepoorter, Chem. Rev. 1981, 81, 447-474.
a) B. Hammer, J. K. Nørskov, Surf. Sci. 1995, 343, 211-220; b) A.
[
composition analysis.
Ruban, B. Hammer, P. Stoltze, H. L. Skriver, J. K. Nørskov, Journal of
Molecular Catalysis A Chemical 1997, 115, 421-429.
N
2
-adsorption isotherms were measured on the apparatus (ASAP2020C)
[3]
Harrington, N. B. Jackson, A. G. Sault, A. K. Datye, J. Catal. 1995, 156, 185-
07; b) T. Herranz, S. Rojas, F. Perezalonso, M. Ojeda, P. Terreros, J. Fierro,
J. Catal. 2006, 243, 199-211; c) J.-l. Tu, M.-y. Ding, Q. Zhang, Y.-l. Zhang, C.-
g. Wang, T.-j. Wang, L.-l. Ma, X.-j. Li, ChemCatChem 2015, 7, 2323-2327.
a) M. D. Shroff, D. S. Kalakkad, K. E. Coulter, S. D. Kohler, M. S.
at 77 K. The BET method was employed to measure the specific surface
area. Pore volume and pore diameter distribution were deduced from
BJH pore analysis.
2
[
1
[
4]
60, 982-989.
5] a) I. O. Pérez De Berti, J. F. Bengoa, S. J. Stewart, M. V. Cagnoli, G.
M. Ding, Y. Yang, B. Wu, Y. Li, T. Wang, L. Ma, Applied Energy 2015,
X-ray photoelectron spectroscopy (XPS) measurements were performed
on the Thermo Scientific ESCALAB 250Xi equipment, which was used to
determine the surface composition and valence state of the elements.
Pecchi, S. G. Marchetti, J. Catal. 2016, 335, 36-46; b) S. Hayashi, Y. Iguchi,
ISIJ Int. 1997, 37, 16-20; c) W. Arabczyk, W. Konicki, U. Narkiewicz, Solid
State Phenomena 2003, 94, 181-184; d) M. Luo, H. Hamdeh, B. H. Davis,
Catal. Today 2009, 140, 127-134; e) D. B. Bukur, K. Okabe, M. P. Rosynek, C.
P. Li, D. J. Wang, K. R. P. M. Rao, G. P. Huffman, J. Catal. 1995, 155, 353-
365.
2
H -temperature programmed reduction (H
2
-TPR) was performed on a
/N and the outlet
homemade equipment. The reduction gas was 5%H
2
2
gas was monitored by a thermal conductivity detector (TCD). The mass
of catalyst was 20 mg and was heated up to 1000C at a rate of
[6]
a) T. Matsue, Y. Yamada, Y. Kobayashi, Hyperfine Interact. 2012, 205,
31-35; b) H. Song, X. Chen, Chem. Phys. Lett. 2003, 374, 400-404.
10C/min.
This article is protected by copyright. All rights reserved.

ChemCatChem
10.1002/cctc.201701424
FULL PAPER
[
7]
a) Y. Gu, M. Qin, Z. Cao, B. Jia, X. Wang, X. Qu, P. A. Joy, J. Am.
Ceram. Soc. 2016, 99, 1443-1448; b) R. Phienluphon, P. Ai, X. Gao, Y.
Yoneyama, P. Reubroycharoen, T. Vitidsant, N. Tsubaki, Catal. Sci. Technol.
2016, 6, 7597-7603.
[
8] a) Y. Jiang, S. Yang, Z. Hua, H. Huang, Angew. Chem. 2009, 48, 8529-
8
2
531; b) C. Cannas, A. Musinu, A. D. Peddis, G. Piccaluga, Chem. Mater.
006, 18, 3835-3842.
[
9]
a) L. Shi, W. Shen, G. Yang, X. Fan, Y. Jin, C. Zeng, K. Matsuda, N.
Tsubaki, J. Catal. 2013, 302, 83-90; b) L. Shi, Y. Jin, C. Xing, C. Zeng, T.
Kawabata, K. Imai, K. Matsuda, Y. Tan, N. Tsubaki, Applied Catalysis A:
General 2012, 435-436, 217-224; c) L. Shi, K. Tao, T. Kawabata, T.
Shimamura, X. J. Zhang, N. Tsubaki, ACS Catalysis 2011, 1, 1225-1233; d) L.
Shi, C. Zeng, Q. Lin, P. Lu, W. Niu, N. Tsubaki, Catal. Today 2014, 228, 206-
2
11; e) R. Phienluphon, L. Shi, J. Sun, W. Niu, P. Lu, P. Zhu, T. Vitidsant, Y.
Yoneyama, Q. Chen, N. Tsubaki, Catalysis Science & Technology 2014, 4,
099; f) L. Shi, P. Zhu, R. Yang, X. Zhang, J. Yao, F. Chen, X. Gao, P. Ai, N.
Tsubaki, Catal. Commun. 2017, 89, 1-3.
10] a) S. Yan, W. Ling, E. Zhou, J. Cryst. Growth 2004, 273, 226-233; b) S.
Ramesh, Journal of Nanoscience 2013, 2013, 1-8.
11] M. K. Gnanamani, H. H. Hamdeh, G. Jacobs, W. D. Shafer, D. E.
Sparks, R. A. Keogh, B. H. Davis, 2014.
12] Y. Cheng, J. Lin, K. Xu, H. Wang, X. Yao, Y. Pei, S. Yan, M. Qiao, B.
Zong, ACS Catalysis 2016, 6, 389-399.
13] J.-D. Xu, Z.-Y. Chang, K.-T. Zhu, X.-F. Weng, W.-Z. Weng, Y.-P. Zheng,
C.-J. Huang, H.-L. Wan, Applied Catalysis A: General 2016, 514, 103-113.
14] a) R. Brown, M. E. Cooper, D. A. Whan, Applied Catalysis 1982, 3,
3
[
[
[
[
[
177-186; b) A. J. H. M. Kock, H. M. Fortuin, J. W. Geus, J. Catal. 1985, 96,
261-275; c) I. S. C. Hughes, J. O. H. Newman, G. C. Bond, Applied Catalysis
1987, 30, 303-311; d) H. Hayakawa, H. Tanaka, K. Fujimoto, Applied Catalysis
A General 2006, 310, 24-30.
15] M. Al-Dossary, J. L. G. Fierro, J. J. Spivey, Industrial & Engineering
Chemistry Research 2015, 54, 911-921.
16] A. Fꢀhlisch, M. Nyberg, P. Bennich, L. Triguero, J. Hasselstrꢀm, O.
Karis, L. G. M. Pettersson, A. Nilsson, The Journal of Chemical Physics 2000,
12, 1946.
[
[
1
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Entry for the Table of Contents
FULL PAPER
[
a, b]
Author(s), Yingying Xue,
Yongbiao
[
c]
[a, b]
[a]
Zhai, Zheng Chen,
Juan Zhang,
Jiaqiang Sun, Mohamed Abbas,
[
a]
[a, d]
[
e]
Yilong Chen,
Corresponding Author(s)* Jiangang
[
a]
Chen*
The glucose content plays an crucial role in manipulating the phase, morphology,
texture, reduction behaviour and catalytic performance of iron precursors in this
novel sol-gel autocombustion combined carbothermal method.
Page No. 1– Page No.6
Sol-gel autocombustion combined
carbothermal synthesis of iron-based
catalysts for Fischer-Tropsch
reaction
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