Improvement of low-temperature catalytic activity over hierarchical Fe-Beta catalysts for selective catalytic reduction of NOx with NH3

Article abstract of DOI:10.1016/j.cclet.2019.03.011

Hierarchical Fe-Beta obtained by hydrothermal synthesis exhibited higher low-temperature NH₃-SCR activity than conventional Fe-Beta. In order to identify the main factors leading to the difference in catalytic activity, we investigated the pore

Full text of DOI:10.1016/j.cclet.2019.03.011

Accepted Manuscript
Title: Improvement of low-temperature catalytic activity over
hierarchical Fe-Beta catalysts for selective catalytic reduction
of NO with NH
x
3
Authors: Na Zhu, Zhihua Lian, Yan Zhang, Wenpo Shan,
Hong He
PII:
DOI:
Reference:
S1001-8417(19)30106-8
https://doi.org/10.1016/j.cclet.2019.03.011
CCLET 4847
To appear in:
Chinese Chemical Letters
Please cite this article as: Zhu N, Lian Z, Zhang Y, Shan W, He H, Improvement
of low-temperature catalytic activity over hierarchical Fe-Beta catalysts for
selective catalytic reduction of NO with NH , Chinese Chemical Letters (2019),
x
3
https://doi.org/10.1016/j.cclet.2019.03.011
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Communication
Improvement of low-temperature catalytic activity over hierarchical Fe-Beta
catalysts for selective catalytic reduction of NO
x
with NH
3
Na Zhu a,b, £, Zhihua Lian a, £, Yan Zhang , Wenpo Shan a,c , Hong He a,b,c,d
a,c
a
Center for Excellence in Regional Atmospheric Environment and Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese
Academy of Sciences, Xiamen 361021, China
b
University of Chinese Academy of Sciences, Beijing 100049, China
Ningbo Urban Environment Observation and Research Station-NUEORS, Institute of Urban Environment, Chinese Academy of Sciences, Ningbo 315800,
c
China
d
State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of
Sciences, Beijing 100085, China

Corresponding author.
E-mail address: wpshan@iue.ac.cn
These two authors contributed equally to this work.
£
Graphical Abstract
Hierarchical Fe-Beta exhibited higher low-temperature NH
and better dispersion of Fe species.
3
-SCR activity than conventional Fe-Beta, due to more active sites
—
——

ARTICLE INFO
ABSTRACT
Article history:
Hierarchical Fe-Beta obtained by hydrothermal synthesis exhibited higher low-temperature
Received 27 January 2019
Received in revised form 1 March 2019
Accepted 5 March 2019
Available online
3
NH -SCR activity than conventional Fe-Beta. In order to identify the main factors leading to
the difference in catalytic activity, we investigated the pore structure, acidity and Fe sites of the
hierarchical Fe-Beta and conventional Fe-Beta. The enhanced activity of hierarchical Fe-Beta
was mainly due to the increase of the quantity of active Fe species. NH
results of NH adsorption clearly verified that hierarchical Fe-Beta had more Lewis acid sites,
which is beneficial to the adsorption and activation of NH . The H -TPR, UV-vis DRS, and
3
-TPD and DRIFTS
3
3
2
Keywords:
Hierarchical structure
Fe-Beta
NH -SCR
3
Low-temperature activity
Kinetics
EPR results confirmed that the hierarchical Fe-Beta had more isolated active Fe species, which
may be associated with that the hierarchical structure introduced more structural defects as ion-
exchange sites. Based on the analysis of kinetics experiments and the above-mentioned
characterizations, it can be concluded that the improvement of NH -SCR activity was not due
3
to an intrinsic effect of the specific structural characteristics, but was related to more Fe active
sites and better dispersion of Fe species in the hierarchical Fe-Beta.
Iron-based zeolites (mostly Fe-ZSM-5 and Fe-Beta) have been
extensively investigated because of their high activity and
2
catalysts presented excellent N selectivity. The relationship of
structure and activity was discussed in detail as follows.
thermal stability for the selective catalytic reduction of NO
x
with
NH (NH -SCR) [1-6]. Compared with ZSM-5, Beta zeolite is an
attractive host for iron and Fe-Beta zeolite has higher activity
than Fe-ZSM-5 in some catalytic reactions [7, 8]. Many studies
3
3
Beta
Hierarchical Beta
Fe-Beta
1
00
Hierarchical Fe-Beta
8
6
4
0
0
0
-
1
GHSV=200,000 h
focused on Fe-Beta catalysts for N
NH -SCR, especially on the active sites and hydrothermal
stability [1, 12, 13]. Previous studies suggested that the low-
temperature NH -SCR activity of Fe-Beta could be enhanced by
bimetallic doping (such as Cu [14], Mn [15], Ce [16, 17]) and
high-temperature H -pretreatment [2, 6].
2
O decomposition [8-11] and
3
1
00
8
0
3
60
4
2
0
0
0
20
0
2
1
50 200 250 300 350 400 450 500
Temperature (°C)
Hierarchical zeolites contain both micro and meso-
macrospores, which can eliminate diffusion limitations and
/
150 200 250 300 350 400 450 500
Temperature (°C)
promote the accessibility of reactants to the active sites [18-21].
The predominant approach for the synthesis of hierarchical
structure zeolites is demetallation (desiliconization and
dealumination) and recrystallization with the surfactants [19, 22].
Fig. 1. NO
x
conversion and N
Beta and Beta catalysts. Reaction conditions: [NO] = [NH
ppm, [O ] = 5 vol%, N balance and GHSV = 200,000 h .
2 2
2
selectivity (inserted) results of Fe-
] = 500
3
-
1
3
Previous studies suggested that NH -SCR activity was enhanced
by introducing hierarchical structure to Fe-ZSM-5 [23, 24].
However, there are few open literatures about hierarchical Fe-
The XRD patterns (Fig. S1 in Supporting information) show
that all samples are phase-pure zeolites with the BEA framework
structure. The peak intensity of Fe-Beta and hierarchical Fe-Beta
declined, which may be due to the collapse or blocking of the
partial microspore of zeolite. FeO species were not detected,
x
which may be due to the Fe species existing as amorphous or
high dispersion on the zeolite support [27, 28].
The textural properties in Table S1 and Fig. S2 (Supporting
information) show that the total volume, external surface area
and BET surface area of hierarchical Beta are larger than those of
Beta, indicating that mesopores and/or macropores are introduced
into Beta to form hierarchical structure [19, 20]. After doping
with Fe, the BET surface area of both Fe-Beta and hierarchical
Fe-Beta decreased, indicating that the partial microspore may be
blocked, in agreement with the XRD results. ICP analysis
revealed that the Fe content of Fe-Beta and hierarchical Fe-Beta
was 2.82% and 3.71%, respectively, suggesting that hierarchical
Fe-Beta could achieve a large amount of iron at the exchange
sites under the identical ion-exchange procedure.
Comparing TEM images of hierarchical Fe-Beta (Fig. S3, c
and d) with those of Fe-Beta (Fig. S3, a and b), the smaller
crystal size and some hollow Beta structure were obtained during
the hydrothermal synthesis, indicating the formation of micro-
macroporous structure. This result is in accordance with the BET
Beta for NH
In this work, hierarchical Fe-Beta zeolites catalysts were
prepared by hydrothermal synthesis and evaluated for NH -SCR.
3
-SCR.
3
The preparation procedure and activity tests are shown in the
Support information. It was found that the low-temperature
activity of hierarchical Fe-Beta was higher than that of Fe-Beta.
The structure and activity relationship was discussed in detail.
As shown in Fig. 1, it was clear that the Beta was active for the
SCR reaction in a narrow temperature range of 375-500 °C.
Acidity may account for its catalytic performance [25, 26].
Hierarchical Beta zeolite showed obviously improved NO
conversions in the whole temperature range. This result indicated
that hierarchical Beta zeolite may have more acid sites than Beta,
3 3
which will be verified in the subsequent NH -TPD and NH
adsorption sections. After the doping of Fe, the Fe-Beta and
hierarchical Fe-Beta indicated highly improved SCR activity as
compared with Beta and hierarchical Beta in the whole
temperature of 150-500 °C. Hierarchical Fe-Beta showed
enhanced low-temperature SCR activity compared with Fe-Beta
obtained using the same ion-exchanged procedure. All of these

results. In Fig. S3c, the hollow zeolite was made of a
polycrystalline micro-mesoporous shell and macropore core.
Previous studies suggested that hollow Beta single crystals were
much more difficult to prepare [18]. The absence of Al zoning
prohibited the use of the dissolution-recrystallization strategy
employing in the synthesis of hollow Beta zeolite single crystals
2
shown in Fig. 2. There is no clear H consumption signal for the
Beta and hierarchical Beta. Two reduction peaks appeared on the
Fe-Beta and hierarchical Fe-Beta. The overlapped reduction
peaks centered at 354 °C (369 °C) and 441 °C (499 °C) were
3
+
2+
attributed to the reduction of isolated Fe to Fe [36] and
oligomeric iron oxo species or tiny Fe into Fe , respectively
2
O
3
3 4
O
[
29].
UV-vis DR spectroscopy is an effective and common method
[37-39]. The reduction temperature of Fe species over
hierarchical Fe-Beta was lower than Fe-Beta, which may be due
for determining the nature and distribution of Fe species in Fe-
zeolites. Fig. S4a (Supporting information) shows the UV-vis DR
spectra of the Fe-Beta samples. The spectra were deconvoluted
into sub-sands, which can be attributed to specific Fe species in
the Fe-zeolites. The bands at 211 and 277 nm were respectively
to the better dispersion of Fe species. The amount of H
2
consumption of hierarchical Fe-Beta was larger than Fe-Beta,
indicating that hierarchical Fe-Beta catalyst had more Fe active
sites. The better redox performance resulted in the enhanced
3
NH -SCR activity on the hierarchical Fe-Beta.
3
+
assigned to isolated Fe ions in tetrahedral and octahedral
coordination environments [30]. The bands at 300-400 nm
In view of the analysis of UV-vis DRS, EPR and H -TPR
2
results above, we have confirmed that more Fe active species
existed on the hierarchical Fe-Beta and dispersed better than
those on Fe-Beta, which may be due to the specific hierarchical
structure.
3
+
indicated the presence of small oligomers Fe
channels [8, 28], and the adsorption bands above 400 nm were
attributed to the presence of bulky Fe nanoparticles on the
x y
O in the zeolite
2
O
3
external surface of the zeolite [31, 32]. Fig. S4b (Supporting
information) shows the UV-vis DR spectra of hierarchical Fe-
Beta samples, the peak attributions are similar to Fe-Beta
samples. The amount of Fe species was estimated semi-
quantitatively based on the relative intensities of these sub-bands
derived from UV-vis DR spectra and the total Fe loading in the
zeolite. The data in Table S2 in Supporting information shows
To identify the strength of the acid sites of hierarchical Fe-
Beta, the NH
are shown in Fig. 3. Beta zeolite showed NH
3
-TPD experiments were carried out and the results
desorption peaks at
3
the range of 100-500 °C, assigning to the desorption of ammonia
species from weak Lewis acid sites (167 °C), strong Lewis acid
sites (262 °C and 330 °C) and strong Brønsted acid sites (373 °C)
[25, 37, 40]. The intensity of the desorption peak at 262 °C was
much stronger than that of peak at 373 °C, suggesting that Beta
zeolite had more Lewis acid sites because of its structural defects
caused by the unsaturated bonding of silicon [41, 42]. When
forming the hierarchical structure, the peaks shifted to the high-
temperature, demonstrating the formation of the stronger acid
sites. The peak at 89 °C on hierarchical Beta may be attributed to
3
+
that isolated Fe ions are the predominant species in Fe-Beta and
hierarchical Fe-Beta catalysts. Previous studies suggested
3
+
isolated Fe species are active sites for NH
3
-SCR on Fe-Beta
catalysts [4,5,25,33,34]. When the Fe loadings were considered,
3
+
the hierarchical Fe-Beta had the larger content of isolated Fe
species than Fe-Beta, resulted in the enhanced NH
performance.
3
-SCR
3
physisorbed NH [39, 43]. The number of acid sites of
EPR spectroscopy was further employed to identify the nature
of different Fe species, the corresponding results are illustrated in
Fig. S5 (Supporting information). Signals at g=2.0, g=4.3 and
g=8.8 were observed for Fe-Beta and hierarchical Fe-Beta. The
signals at g=4.3, g=8.8 and g=2 were generally attributed to
isolated Fe species in tetrahedral and distorted tetrahedral
coordination [30, 35], isolated Fe species with a distorted
octahedral environment [8, 13] and isolated Fe species in a high
hierarchical Beta also increased, which resulted in the enhanced
SCR activity, compared with Beta zeolite (Fig. 1). When Fe was
introduced into Beta, the NH
desorption peak shifted to high-temperature. However, when Fe
was exchanged to hierarchical Beta, the NH desorption peak
3
storage capacity decreased, and the
3
shifted to the low-temperature, to form more weak Lewis acid
sites (167 °C), which is beneficial to the adsorption and
activation of NH .
3
symmetry octahedral coordination or oligonuclear Fe
O
x y
clusters
167
Hierarchical Fe-Beta
Fe-Beta
Hierarchicla Beta
Beta
[
8, 28], respectively. Overall, the EPR signal intensity of
262
3
30
3
hierarchical Fe-Beta was higher than Fe-Beta, illustrating the
amount of isolated Fe species on hierarchical Fe-Beta was higher
than that of Fe-Beta, in agreement with UV-vis DRS results.
73
8
9
3
54
4
41
H
consumption
2
(
mol/g)
1
40.5
369
Hierarchical Fe-Beta
Fe-Beta
1
00
200
300
400
500
600
700
800
4
99
Temperature (°C)
3
-TPD profiles of different Beta zeolites.
Fig. 3. NH
129.4
Hierarchical Beta
Beta
In order to understand the adsorption performance and reaction
mechanism, in situ DRIFTS experiments were carried out for Fe-
Beta and hierarchical Fe-Beta, as shown in Fig. S6 in Supporting
2
00
400
600
800
Temperature (°C)
information. After the adsorption of NH
3 2 3
and N purge, the NH
Fig. 2. H
2
-TPR results of the different Beta samples.
adsorbed peaks appeared on both of the catalysts. The negative
-1
bands at 3773, 3721, 3604 cm was assigned to Al-OH groups,
terminal Si-OH, isolated bridging acidic hydroxyl stretching
In order to investigate the redox performance of the samples,
the H -TPR experiments were conducted and the results are
2

vibrations (Si(OH)Al), respectively [44-46]. The negative band at
meso/macrospores were introduced to Beta zeolite. Hierarchical
Fe-Beta exhibited better low-temperature activity than Fe-Beta.
-
1
3
675 cm only appeared on hierarchical Fe-Beta, which was
attributed to hydroxyls bonded on extra-framework Al species
47], due to hierarchical structure. This result indicated that
The results of UV-vis DRS, EPR and H
2
-TPR indicated that
2 3
isolated Fe , oligomers and Fe O coexisted on Fe-Beta and
3
+
[
hierarchical structure introduced more exchanged sites and acid
sites, which led to the better SCR activity. In the N-H stretching
hierarchical Fe-Beta. The enhanced activity of the hierarchical
Fe-Beta was related to the prominent presence of highly
dispersed Fe active species, which may be because that the
hierarchical structure introduced more defects to provide more
ion-exchange sites for Fe species. The kinetic experiments
demonstrated that the activate energy of Fe-Beta and hierarchical
Fe-Beta was 56.2 and 56.9 kJ/mol, respectively, suggesting an
-
1
regions (3100-3500 cm ), the bands corresponding to the
-
1
asymmetric stretching (3343cm ) and symmetric stretching
-
1
(
3
3273 and 3192 cm ) of coordinated NH on Lewis acid sites
-
1
were observed, respectively [48]. The bands at 1478 cm and
163 cm were attributed to the NH
Brønsted acid sites and coordinated NH
acid sites, respectively [48-50] . The band at 896 cm could be
assigned to T-O-T framework vibrations by Fe species [7]. The
-
1
+
1
4
ions adsorbed on the
adsorbed on the Lewis
3
identical rate controlling mechanism. The NH
results of NH adsorption indicated that the hierarchical Fe-Beta
had more acid sites for the adsorption and activation of NH . The
adsorption of NO was not clearly observed on Fe-Beta or
hierarchical Fe-Beta, indicating that NH -SCR process of both of
3
-TPD and DRIFTS
-
1
3
3
-
1
peak intensity at 896 cm of hierarchical Fe-Beta was higher than
that of Fe-Beta, illustrating more Fe was incorporated into
x
3
hierarchical Fe-Beta, in agreement with the ICP, EPR and H
2
-
the two catalysts mainly followed the Eley-Rideal (E-R) reaction
mechanism.
TPR results. Overall, the intensity of NH adsorption peaks for
3
hierarchical Fe-Beta was higher than those for Fe-Beta,
suggesting more acid sites existing on hierarchical Fe-Beta than
Acknowledgments
those on Fe-Beta, in accordance with NH
The NO adsorbed spectra were shown in Fig. S6b. No peak for
NO adsorbed species was clearly observed, suggesting that Fe-
Beta and hierarchical Fe-Beta did not adsorb NO species. The
NO adsorbed species were not detected on the Fe-Beta and
hierarchical Fe-Beta, but the excellent NO conversion could be
obtained, illustrating that the NH -SCR reaction may mainly
carried out through Eley-Rideal (E-R) pathway with gaseous NO
3
-TPD results.
We gratefully acknowledge the financial supports from the
National Natural Science Foundation of China (Nos. 51822811,
x
2
2
1637005), the National Key R&D Program of China (Nos.
017YFC0212502, 2017YFC0211101), and the Young Talent
x
x
Project of the Center for Excellence in Regional Atmospheric
Environment, CAS (No. CERAE201806).
x
3
References
reacting with adsorbed NH
3
species on both of the catalysts.
[
1] S. Shwan, R. Nedyalkova, J. Jansson, et al., Ind. Eng. Chem. Res.
1 (2012) 12762-12772.
-3.5
-4.0
-4.5
-5.0
-5.5
-6.0
5
[2] R. Nedyalkova, S. Shwan, M. Skoglundh, L. Olsson, Appl. Catal.
B: Environ. 138 (2013) 373-380.
Hierarchical Fe-Beta
E = 56.2 5.9 kJ/mol
a
[
[
3] H. Chen, W.M.H. Sachtler, Catal. Today 42 (1998) 73-83.
4] P. Balle, B. Geiger, D. Klukowski, et al., Appl. Catal. B: Environ.
Fe-Beta
E = 56.9 2.8 kJ/mol
9
1 (2009) 587-595.
5] P. Balle, B. Geiger, S. Kureti, Appl. Catal. B: Environ. 85 (2009)
09-119.
a
[
[
1
6] S. Shwan, J. Jansson, L. Olsson, M. Skoglundh, Catal. Sci.
Technol. 4 (2014) 2932-2937.
[7] M. Mauvezin, G. Delahay, B. Coq, et al., J. Phys. Chem. B 105
(2001) 928-935.
[8] J. Perez-Ramirez, J.C. Groen, A. Bruckner, et al., J. Catal. 232
(2005) 318-334.
[9] J.A.Z. Pieterse, G.D. Pirngruber, J.A. van Bokhoven, S.
Booneveld, Appl. Catal. B: Environ. 71 (2007) 16-22.
0.0023
0.0024
0.0025
0.0026
1
/T (1/K)
Fig. 4. Arrhenius plots of the SCR reaction rates over Fe-Beta and
hierarchical Fe-Beta in the feed gas of 500 ppm NO/ 500 ppm NH
.0% vol. % O / N (500 mL/min, 40 mg catalysts, GHSV: 400,000
3
/
5
h ).
2
2
-
1
[
[
[
10] K. Jisa, J. Novakova, M. Schwarze, et al., J. Catal. 262 (2009)
7-34.
11] S. Sklenak, P.C. Andrikopoulos, B. Boekfa, et al., J. Catal. 272
2010) 262-274.
2
In order to obtain further understanding of the intrinsic effect
of hierarchical structure on the NH -SCR reaction, the kinetic
3
(
experiments were performed on the Fe-Beta and hierarchical Fe-
Beta, as shown in Fig. 4. The apparent activation energy obtained
from the Arrhenius plots for Fe-Beta and hierarchical Fe-Beta
was 56.9 and 56.2 kJ/mol, respectively, in agreement with those
for Fe-zeolite reported in the previous literature (Ea = 40~54
kJ/mol) [31, 51, 52]. The two catalysts had similar activation
energy, indicating an identical rate controlling mechanism [13].
Since there were no mass transfer related limitations, hierarchical
Fe-Beta catalyst had better SCR activity, demonstrating the
higher activity was mainly caused by higher amount of Fe active
12] S. Shwan, R. Nedyalkova, J. Jansson, et al., Top. Catal. 56
(2013) 80-88.
[13] H. Liu, J. Wang, T. Yu, S. Fan, M. Shen, Catal. Sci. Technol. 4
2014) 1350-1356.
14] L. Xu, C. Shi, B. Chen, et al., Micropor. Mesopor. Mat. 236
2016) 211-217.
(
[
[
[
(
15] D.S. Krivoruchenko, A.V. Kucherov, N.S. Telegina, et al., Russ.
Chem. Bulletin 63 (2014) 389-395.
16] S. Jiang, R. Zhou, Fuel Process. Technol. 133 (2015) 220-226.
[17] J. Li, L. Jia, W. Jin, F. Xia, J. Wang, Rare Metal Mat. Eng. 44
2015) 1612-1616.
(
[18] C. Pagis, A.R.M. Prates, D. Farrusseng, N. Bats, A. Tuel, Chem.
sites [53], in accordance with the H
results.
2
-TPR and UV-vis DRS
Mat. 28 (2016) 5205-5223.
[
[
19] E. Koohsaryan, M. Anbia, Chin. J. Catal. 37 (2016) 447-467.
20] L. Chen, X. Li, J.C. Rooke, et al., J. Mat. Chem. 22 (2012)
In summary, hierarchical Beta was prepared by hydrothermal
synthesis. The BET and TEM results confirmed that the
1
7381-17403.

[
[
[
[
[
[
[
[
[
[
[
[
[
[
[
21] F. Xiao, L. Wang, C. Yin, et al., Angew. Chem. Int. Edit. 45
2006) 3090-3093.
22] K. Na, M. Choi, R. Ryoo, Micropor. Mesopor. Mat. 166 (2013)
-19.
23] P.N.R. Vennestrom, M. Grill, M. Kustova, et al., Catal. Today
68 (2011) 71-79.
24] J. Ma, D. Weng, X. Wu, Z. Si, Z. Wu, Prog. Nat. Sci. Mat. 23
2013) 493-500.
25] L. Ma, H. Chang, S. Yang, et al., Chem. Eng. J. 209 (2012) 652-
60.
26] Y. Zhu, B. Chen, R. Zhao, et al., Catal. Sci. Technol. 6 (2016)
581-6592.
27] M. Jablonska, G. Delahay, K. Kruczala, et al., J. Phys. Chem. C
20 (2016) 16831-16842.
28] H. Xia, H. Hu, S. Xu, K. Xiao, S. Zuo, Biomass Bioenerg. 108
2018) 426-432.
(2016) 2069-2078.
(
[38] H. Pan, Y. Guo, H. Bi, Chem. Eng. J. 280 (2015) 66-73.
[39] L. Ma, J. Li, H. Arandiyan, et al., Catal. Today 184 (2012) 145-
152.
[40] L. Xu, C. Shi, Z. Zhang, et al., Micropor. Mesopor. Mat. 200
(2014) 304-310.
[41] P. Boron, L. Chmielarz, J. Gurgul, et al., Micropor. Mesopor.
Mat. 203 (2015) 73-85.
[42] Q. Zeng, X. Bai, J. Zheng , J. Chen, R. Li, Chin. Chem. Lett. 22
(2011) 1103-1106.
[43] S. Yang, J. Li, C. Wang, et al., Appl. Catal. B: Environ. 117
(2012) 73-80.
[44] J.H. Baek, S.M. Lee, J.H. Park, et al., J. Ind. Eng. Chem. 48
(2017) 194-201.
[45] S. Shwan, E.C. Adams, J. Jansson, M. Skoglundh, Catal. Lett.
143 (2013) 43-48.
[46] W. Su, H. Chang, Y. Peng, C. Zhang, J. Li, Environ. Sci.
Technol. 49 (2015) 467-473.
[47] E. Bourgeat-Lami, P. Massiani, F.D. Renzo, et al., Appl. Catal.
A: Gen. 72 (1991) 139-152.
[48] S. Song, G. Wu, W. Dai, N. Guan, L. Li, Catal. Sci. Technol. 6
(2016) 8325-8335.
[49] S.A. Skarlis, D. Berthout, A. Nicolle, C. Dujardin, P. Granger, J.
Phys. Chem. C 117 (2013) 7154-7169.
[50] Y. Peng, W. Yu, W. Su, X. Huang, J. Li, Catal. Today 242 (2015)
300-307.
[51] H. Huang, R.Q. Long, R.T. Yang, Appl. Catal. A: Gen. 235
(2002) 241-251.
[52] P. Sazama, B. Wichterlova, S. Sklenak, et al., J. Catal. 318
(2014) 22-33.
3
1
(
6
6
1
(
29] A.R.M. Prates, C. Pagis, F.C. Meunier, et al., Cryst. Growth.
Des. 18 (2018) 592-596.
30] A. Wang, Y. Wang, E.D. Walter, et al., J. Catal. 358 (2018) 199-
2
10.
31] S. Brandenberger, O. Krocher, A. Tissler, R. Althoff, Appl.
Catal. B: Environ. 95 (2010) 348-357.
32] M.S. Kumar, M. Schwidder, W. Grunert, A. Bruckner, J. Catal.
2
27 (2004) 384-397.
33] D.E. Doronkin, A.Y. Stakheev, A.V. Kucherov, et al., Top. Catal.
2 (2009) 1728-1733.
5
34] M. Hoj, M.J. Beier, J.D. Grunwaldt, S. Dahl, Appl. Catal. B:
Environ. 93 (2009) 166-176.
35] M.Y. Kim, K.W. Lee, J.H. Park, et al., Korean J. Chem. Eng. 27
(2010) 76-82.
[
[
36] R.Q. Long, R.T. Yang, J. Catal. 194 (2000) 80-90.
37] Y. Xia, W. Zhan, Y. Guo, Y. Guo, G. Lu, Chin. J. Catal. 37
[53] I. Melian-Cabrera, E.R.H. van Eck, S. Espinosa, et al., Appl.
Catal. B: Environ. 203 (2017) 218-226.