Application of magnetic field to CO hydrogenation using a confined-space catalyst: effect on reactant gas diffusivity and reactivity

Article abstract of DOI:10.1039/d0ra09870a

An external magnetic field has recently been applied in reaction processes to promote movement and avoid agglomeration of magnetic particles, and also reduce the activation energy through improving the gas-solid contact. In this work, the effect of an external magnetic field on reactant gas diffusivity and reactivity in CO hydrogenation within a confined-space catalyst was investigated for the first time using a conventional reactor packed with a bimetallic 5Fe-5Co/ZSM-5 molecular sieve catalyst. The synergistic effect between magnetic field and limited mass transfer within zeolite cavities improved the mass transfer ability and reaction phenomena of the reactant molecules, leading to enhancement of catalytic activity with tailored reaction pathways. As a result, CO conversion and CH4 selectivity were increased by factors of 1.9 and 1.3 compared to those without a magnetic field. These synergistic interactions are able to provide an innovative challenge for green and sustainable chemical processes and separation processes by means of selective reactant and product mass transfer designed for selective catalytic conversion in the future.

Full text of DOI:10.1039/d0ra09870a

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Application of magnetic field to CO hydrogenation
using a confined-space catalyst: effect on reactant
gas diffusivity and reactivity
Cite this: RSC Adv., 2021, 11, 3990
Waleeporn Donphai,ab Naphaphan Kunthakudee,a Sirapat Munpollasri,ab
Pariyawalee Sangteantong,ab Surangrat Tonlublao,c Wanwisa Limphirat,c
ab
Yingyot Poo-arporn,c Sirapassorn Kiatphuengpornd and Metta Chareonpanich
*
An external magnetic field has recently been applied in reaction processes to promote movement and avoid
agglomeration of magnetic particles, and also reduce the activation energy through improving the gas–
solid contact. In this work, the effect of an external magnetic field on reactant gas diffusivity and
reactivity in CO hydrogenation within a confined-space catalyst was investigated for the first time using
a
conventional reactor packed with a bimetallic 5Fe–5Co/ZSM-5 molecular sieve catalyst. The
synergistic effect between magnetic field and limited mass transfer within zeolite cavities improved the
mass transfer ability and reaction phenomena of the reactant molecules, leading to enhancement of
catalytic activity with tailored reaction pathways. As a result, CO conversion and CH4 selectivity were
increased by factors of 1.9 and 1.3 compared to those without a magnetic field. These synergistic
interactions are able to provide an innovative challenge for green and sustainable chemical processes
and separation processes by means of selective reactant and product mass transfer designed for
selective catalytic conversion in the future.
Received 20th November 2020
Accepted 6th January 2021
DOI: 10.1039/d0ra09870a
rsc.li/rsc-advances
performance in the CO hydrogenation reaction due to the
conned spaces in the zeolite microstructure which help
Introduction
promote the re-adsorption ability and secondary reactions (i.e.
cracking, isomerization, and aromatization) of the primary
products, and possesses shape-selective features, leading to
product selectivity towards gasoline-range hydrocarbons.12–15
In addition to the catalyst and support, various key param-
eters, such as reactant gas pressure, reaction temperature, and
space velocity, also strongly inuence the CO hydrogenation
reaction. Recently, an external magnetic eld has been applied
for the rst time in CO2 reforming,16 photocatalytic reaction,17
Fischer–Tropsch synthesis,18,19 hydrogen production,20 in order
to control and improve the movement of magnetic particles,
avoid agglomeration of magnetic particles, and reduce the
activation energy through improving gas–solid contact, respec-
tively.21–23 In previous work,24–26 we tted a catalytic packed bed
reactor with an external magnetic eld and observed signicant
improvement in CO2 hydrogenation over Fe–Cu based catalysts
by means of increased adsorption ability and selectivity to
longer hydrocarbon products.
Carbon monoxide hydrogenation reactions have been explored
and investigated by many researchers. Among these reactions,
Fischer–Tropsch synthesis (FTS) is known as one important route
for converting synthesis gas (CO and H2) to high-quality and
environmentally friendly hydrocarbon fuels.1–3 To improve the
conversion and selectivity for CO hydrogenation, suitable cata-
lysts such as Fe and Co-based catalysts are generally applied. Fe-
based catalysts show high activities for both the FTS reaction and
water–gas shi (WGS) reaction, allowing for efficient utilization
of CO,4–6 while Co-based catalysts are superior at promoting long-
chain hydrocarbons with low WGS activity at low operating
temperatures.7–9 In addition, catalyst supports also play crucial
roles as regards various factors including cluster size of active
metal particles,5 mass transfer of reactants and products,10 and
chemisorption ratio of H2 and CO on the active surfaces.11 Among
the catalyst supports, ZSM-5 zeolite exhibits superior
aKU-Green Catalysts Group, Department of Chemical Engineering, Faculty of
Engineering, Kasetsart University, Bangkok 10900, Thailand. E-mail: fengmtc@ku.
ac.th
bNanocatalysts and Nanomaterials for Sustainable Energy and Environment Research
Network of NANOTEC, Kasetsart University, Bangkok 10900, Thailand
cSynchrotron Light Research Institute, Nakhon Ratchasima 30000, Thailand
dNational Nanotechnology Center, National Science and Technology Development
Agency, Pathumthani 12120, Thailand
Accordingly, it is of a great interest to apply an external
magnetic eld to the CO hydrogenation reaction especially that
in a conventional reactor packed with a conned-space bime-
tallic 5Fe–5Co/ZSM-5 catalyst. The mass transfer ability and
reaction phenomena of reactant molecules are expected to be
improved under magnetic eld and magnied within
a
conned-space ZSM-5 molecular sieve, leading to
3990 | RSC Adv., 2021, 11, 3990–3996
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enhancement of catalytic activity with tailored reaction path-
The reducing temperatures of Fe and Co catalysts and
ways. These synergistic interactions are able to provide an interaction with ZSM-5 zeolite support were examined by using
innovation challenge for simultaneous separation–reaction H2 temperature programmed reduction (H2-TPR: Micromeritics
processes in the future.
AutoChem II chemisorption analyzer). In the TPR experiment,
0.2 g of catalyst was heated in a ow of H2/Ar mixture gas (10%
H2) using a total ow rate of 30 ml minꢁ1. The experiment was
Experimental
ZSM-5 zeolite and 5Fe–5Co/ZSM-5 catalyst preparation
ꢀ
carried out in teꢁm1perature range of 50–1000 C with a heating
ꢀ
rate of 5 C min
.
Local geometry changes of Fe and Co species in catalyst
during reduction stage with H2 gas at a temperature range of
30–400 ꢀC and holding stage of 400 ꢀC for 6 h were investigated
by time resolved X-ray absorption spectroscopy (TR-XAS) at
Beamline 2.2 of the Synchrotron Light Research Institute (SLRI),
Thailand. XANES spectra of Fe K-edge and Co K-edge were
collected in energy ranges of 6975–7525 eV and 7690–7840 eV,
respectively, in the transmission detection mode using ioniza-
tion chamber.
ZSM-5 zeolite support was prepared following the synthesis
process reported by Chareonpanich et al. (2018) using sodium
silicate solution (Na2Si3O7: 4 wt% NaOH; 27 wt% SiO2) as
a silica source, aluminium nitrate (Al(NO3)3$9H2O: 98% purity,
UNILAB) as an alumina source and tetrapropyl ammonium
bromide (C12H28NBr or TPABr: 98% purity, Fluka Chemicals) as
a structure-directing agent. Regarding the synthesis process,
sodium silicate solution was primarily added into the mixture of
TPABr and aluminium nitrate solution, while pH of the mixture
was maintained at 10.5 throughout the mixing process by
adding 1 M HCl solution. The mixture was kept stirring for 0.5 h
and the obtained gel was transferred to a Teon-lined autoclave
and hydrothermally heated at 240 ꢀC for 24 h. The solid product
was ltered and washed with deionized water, dried at 80 ꢀC for
24 h, and calcined in air at 550 ꢀC for 4 h using a heating rate of
Magnetic properties were measured using a vibrating sample
magnetometer (VSM: Lake-Shore7404) with an external
magnetic eld of 5 kOe at room temperature.
Catalytic CO hydrogenation in external magnetic eld
CO hydrogenation reaction over 5Fe–5Co/ZSM-5 zeolite catalyst
was examined using a packed-bed reactor (SUS-316, O.D. 3/800)
assembled with a magnetic system (a ring cast Alnico perma-
nent magnet: Bunting Magnetics Co. Ltd.; O.D., 1.0 in; I.D., 0.75
in; thickness, 0.5 in; grade 5) with a curie temperature of 840 ꢀC
and a maximum operating temperature of 538 ꢀC. Magnetic
eld orientations (north to south (N–S) and south to north (S–N)
alignments) and magnetic ux density at the catalyst bed were
controlled by varying numbers of magnet pairs.
2 C minꢁ1 to remove TPABr and other volatile contaminants.
ꢀ
In this study, 5 wt% Fe and 5 wt% Co were loaded onto ZSM-5
zeolite support using iron nitrate (Fe(NO3)3$6H2O: 98%, Univar)
and cobalt nitrate hexahydrate (Co(NO3)2$6H2O: 99.95%, Univar)
as metal precursors via incipient wetness impregnation method.
The obtained mixture was dried using microwave irradiatꢀion at
560 W for 2 min, and consecutively calcined in air at 500 C for
5 h using a heating rate of 5 ꢀC minꢁ1. The obtained catalyst was
denoted as 5Fe–5Co/ZSM-5.
In this study, magnetic ux intensities at the catalyst bed
were ꢁ20.8, ꢁ25.1 and ꢁ27.4 mT for two pairs, three pairs, and
four pairs of magnets, respectively, with magnetic eld orien-
tation of N–S alignment. Prior to each experiment, 0.2 g catalyst
packed at the center of magnetic pairs was reduced at 400 ꢀC for
6 h using a H2 ow rate of 50 ml minꢁ1 at atmospheric pressure.
Aer catalyst activation, the reactor was cooled down to room
temperature using He gas, then reactant gases (H2 and CO with
molar ratio of 2) were introduced into the reactor. The reaction
Characterization of textural, chemical, and magnetic
properties of ZSM-5 zeolite and 5Fe–5Co/ZSM-5catalyst
The textural properties of ZSM-5 zeolite support and 5Fe–5Co/
ZSM-5 zeolite catalysts were examined by N2 physisorption
technique using a Quantachrome Autosorb-1C instrument at
ꢁ196 ꢀC. Prior to sorption measurement, the sample was
degassed at 200 ꢀC for 12 h. The specic surface area and pore
size distribution were obtained by using Brunauer–Emmett–
Teller (BET) analysis and t-plot method, and the pore volume
was measured at a relative pressure of 0.995.
The crystallographic structures of ZSM-5 zeolite support and
5Fe–5Co/ZSM-5 catalyst were analyzed by X-ray diffraction
spectroscopy (XRD: TTRAX III) using Cu Ka radiation at high
angle in the 2q range of 5–60ꢀ.
The surface morphology of ZSM-5 zeolite support and 5Fe–
5Co/ZSM-5 catalyst were observed by using eld emission
scanning electron microscopy (FE-SEM: JEOL, JSM-7600F)
operated at 15 keV with Pt-coated on the samples. Fe and Co
elements on the catalyst surface were mapped by using energy-
dispersive X-ray spectroscopy (EDS: OXFORD, XMaxN). The
catalyst structure was examined by using transmission electron
ꢀ
was performed at 320 C at a total pressure of 10 bar.
Effluent gases including H2, CO, CO2, and CH4 were analyzed
by using Shimadzu gas chromatograph (GC-2014) with
a thermal conductivity detector (TCD) and a Unibead-C packed
column, while hydrocarbon products (C1–C5+) were analyzed by
Shimadzu gas chromatograph (GC-8A) with a ame ionization
detector (FID). A Porapak-Q packed column and OV-1 Uniport
HP packed column were used to analyze C1–C4 and C5+ hydro-
carbons, respectively. Activity and selectivity of 5Fe–5Co/ZSM-5
catalyst without an external magnetic eld were also examined
in comparison.
Results and discussion
microscopy (TEM: JEOL JEM-2010) with an acceleration voltage In this work, use of an external magnetic eld and conned-
of 200 kV.
space 5Fe–5Co/ZSM-5 catalyst reactant gas diffusivity and
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catalytic reactivity in CO hydrogenation reaction were system-
atically investigated. Accordingly, ZSM-5 zeolite was prepared by
hydrothermal synthesis, followed by loading of the active
metals via incipient wetness impregnation method. The crys-
talline structures of ZSM-5 support and 5Fe–5Co/ZSM-5 catalyst
were examined by X-ray diffraction spectroscopy (Fig. 1). The
diffraction peaks of both ZSM-5 and 5Fe–5Co/ZSM-5 catalyst
corresponded well to the MFI-type framework,27,28 indicating
good dispersion of Fe2O3 and CuO over ZSM-5 support. The
specic surface areas of ZSM-5 support and 5Fe–5Co/ZSM-5
catalyst were found to be 271 and 227 m2 gꢁ1, respectively,
representing a type I isotherm with H4 hysteresis loop accord-
ing to IUPAC classication (Fig. 2)—indicating the existence of
a microporous structure with narrow slit pores. Pore size
distribution of ZSM-5 zeolite was in the range of 0.3–0.7 nm,
with a maximum of 0.6 nm, while a narrower pore was observed
for 5Fe–5Co/ZSM-5 catalyst (0.4 nm). The fraction of micropore
volume of 5Fe–5Co/ZSM-5 catalyst was reduced by approxi-
mately 13% aer Fe and Co loading due to partial blockages of
metal clusters, which led to this lower specic surface area. The
morphology of 5Fe–5Co/ZSM-5 catalyst, examined by FE-SEM
(Fig. 3), exhibited uniform, aggregated cubic particles with
a mean diameter of approximately 1.1 mm. The EDS result
evidently conrmed the good distribution of iron oxide and
cobalt oxide nanoclusters over the surface of ZSM-5 zeolite
(Fig. 3 (inset)).
The reducibility of the catalysts was evaluated by H2-TPR,
and the reduction proles are presented in Fig. 4. Three
deconvolution peaks of reduction in the temperature range of
200–800 ꢀC are observed in 5Fe–5Co/ZSM-5 catalyst. The rst
peak at lower temperature (317 ꢀC) can be assigned to trans-
formations of Fe2O3 to Fe3O4 and of Co3O4 to CoO.5,6,12 The
second peak (414 ꢀC) is attributed to the reduction of Fe3O4 and
FeO to metallic Fe and of CoO to metallic Co, while the last peak
(452 ꢀC) can be ascribed to the reduction of remaining FeO or of
hardly reducible Fe species.7,29
In situ XANES technique was applied to conrm the trans-
formation of Fe and Co species on 5Fe–5Co/ZSM-5 (Fig. 5). The
XANES spectra in the range 50–340 ꢀC exhibited absorption
edge energy at 7127 eV, indicating the presence of Fe2O3 and
Fe3O4. Increasing the reduction temperature to above 340 ꢀC
Fig. 2 N2 adsorption–desorption isotherm (a) and pore size distribu-
tion (b) of ZSM-5 support and 5Fe–5Co/ZSM-5 catalyst.
under a ow of H2, a gradual shi of the absorption edge energy
towards lower energy was observed, indicating the reduction of
oxidation state of Fe species. In the case of Co species, the
reduction of oxidation state occurred when increasing the
reduction temperature to those higher than 300 ꢀC. In order to
determine the evolution of the oxidation states of Fe and Co
species on ZSM-5 support, linear combination tting was per-
formed on each XANES spectrum at the reduction temperature
of 400 ꢀC, and compared to the XANES spectra of the references
consisting Fe2O3, Fe3O4, FeO and Fe for Fe species, as well as
Co3O4, CoO and Co for Co species. As shown in Fig. 6, the metal
oxide catalysts were transformed to approximately 20% FeO and
70% Fe, and approximately 20% CoO and 80% Co, aer the
reduction process.
The magnetic properties of 5Fe–5Co/ZSM-5 catalyst before
and aer the reduction process at 400 ꢀC were investigated
using a vibrating sample magnetometer (VSM) (Fig. 7). Before
the reduction process, 5Fe–5Co/ZSM-5 catalyst exhibited a small
magnetic hysteresis loop, indicating paramagnetic nature of the
catalyst.30,31 Aer the reduction process, a narrower hysteresis
loop was clearly observed. The saturation (Ms) and remanence
Fig. 3 SEM images of 5Fe–5Co/ZSM-5 catalyst (a) with EDS mapping
Fig. 1 XRD patterns of ZSM-5 support and 5Fe–5Co/ZSM-5 catalyst.
3992 | RSC Adv., 2021, 11, 3990–3996
of Fe (b), Co (c) dispersions and EDS spectrum (d).
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Fig. 4 H2-TPR profile of (a) 5Fe–5Co/ZSM-5, (b) 5Fe/ZSM-5 and (c)
5Co/ZSM-5 catalysts. — TPR profile (experiment);
TPR profile
(program); deconvoluted profile of Fe and Cu oxide species.
Fig. 6 Evolution of Fe and Co species during the reduction of 5Fe–
5Co/ZSM-5 catalyst.
0–27.7 mT (the geomagnetic eld thereby being approx. 0.03–
0.06 mT). It was found that CO conversion under external
magnetic eld increased by a factor of 1.9 compared to that
without magnetic eld. Compared to the reaction over Co/Al2O3
catalyst, CO conversion at 15 mT increased by a factor of 1.1.19
However, the CO conversion showed no signicant variation
using magnetic ux intensities ranging from 20.8–27.4 mT.
It was noted that methane yield signicantly increased, while
CO2 obviously decreased with increasing magnetic ux inten-
sities in the range of 0–27.4 mT. These results indicated that the
external magnetic eld facilitated the activity of 5Fe–5Co/ZSM-5
catalyst through increasing the reverse water–gas shi reac-
tion.32 This may attributed to the effective diffusion of reactant
molecules and their interaction with the catalyst surface under
magnetic eld.
Based on the above results, it was suggested that the selective
CO conversion and product selectivities under external
Fig. 5 In situ Fe K-edge and Co K-edge XANES spectra of 5Fe–5Co/
ZSM-5 catalyst reduction from 50–400 ꢀC and for 4 h holding time.
(Mr) magnetizations of the reduced 5Fe–5Co/ZSM-5 catalyst
both signicantly increased, indicating higher magnetic
responses compared to the unreduced catalyst due to the exis-
tence of a-Fe phase with ferromagnetic property within the
catalyst. In addition, a higher saturation magnetization of 19.0
emu gꢁ1 was observed on the reduced catalyst, compared to 3.6
emu gꢁ1 for the catalyst before reduction.
The performances of 5Fe–5Co/ZSM-5 catalyst in CO hydro-
genation reaction were examined using a magnetic eld-
assisted packed bed reactor operated at 320 ꢀC and 10 bar
with a total ow rate of 30 ml minꢁ1; the results are shown in
Fig. 8 and 9. Magnetic ux intensities were varied in the range of
Fig. 7 Magnetic hysteresis loops of 5Fe–5Co/ZSM-5 catalyst before
and after reduction process at 400 ꢀC.
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compared to inert silica. In addition, H2 diffusivity improved
considerably, more than that of CO under external magnetic
eld as its kinetic diameter (289 pm) is 1.3 times smaller than
that of CO (376 pm). The synergistic effect of the external
magnetic eld and limited mass transfer within zeolite cavities
therefore led to selective CO conversion to methane and larger
hydrocarbon products.
In order to understand the effect of external magnetic eld
on the reactant gas diffusion within the conned space catalyst,
the effective diffusion coefficients (De) of CO and H2 were
calculated using eqn (1)–(5);33 the results are shown in Table 1.
De ¼ Dpore3/s
(1)
Fig. 8 Catalytic performances in terms of H2 and CO conversion over
5Fe–5Co/ZSM-5 using different magnetic flux intensities.
where 3 is catalyst porosity, s is catalyst tortuosity, and Dpore is
diffusivity of CO and H2 in pore, which is obtained from:
1
1
1
¼
þ
(2)
Dpore
DAB Dk
where DAB and Dk are bulk diffusivity (cm2 sꢁ1) and Knudsen
diffusivity (cm2 sꢁ1), respectively. The values of DAB and Dk can
be calculated from the following equations:
0
1
1=2
3
2
1
1
B
@
C
A
0:001858T
þ
1
3
2
MCO
MCO þ MH
2
3
DAB
¼
(3)
(4)
PsCOH 2UD
2
ꢀ
ꢁ
1=2
T
Fig. 9 Product distributions from CO hydrogenation over 5Fe–5Co/
ZSM-5 catalyst for different magnetic flux intensities.
Dk ¼ 9700r
M
where T is reaction temperature (K); MCO and MH are molecular
2
weights of CO and H2, respectively; P is total pressure (atm);
magnetic eld could possibly rely not only on the improvement
of catalyst active surfaces, but also on the diffusion rate of the
reactants into and the product gases from the conned-space
ZSM-5 zeolite based catalyst. In order to conrm the syner-
gistic effect of the external magnetic eld and limited mass
transfer within zeolite cavities, the diffusion of CO and H2
reactant molecules through 5Fe–5Co/ZSM-5 catalyst bed under
external magnetic eld were observed and compared to that
without magnetic eld, as shown in Fig. 10.
˚
sCOH is effective collision diameter (A); UD is collision integral;
2
and r is pore radius (cm).
The tortuosity (s) of 5Fe–5Co/ZSM-5 catalyst in eqn (1), can
be calculated by using eqn (5).34
2
3
,
1
3
4
5
s ¼ 3
1 ꢁ ð1 ꢁ 3Þ
(5)
As shown in Fig. 10, the diffusion rates of both CO and H2
reactant gases were signicantly lowered principally due to the
interaction with –OH functional group on ZSM-5 zeolite
surfaces and limited mass transfer within zeolite cavities
Table 1 shows that effective diffusion coefficients of CO and
H2 in pores of 5Fe–5Co/ZSM-5 catalyst under external magnetic
Table 1 Diffusivities and effective diffusion coefficients of CO and H2
in pores of 5Fe–5Co/ZSM-5 catalyst for different magnetic flux
intensities
Diffusivities in
pores ꢂ 10ꢁ3
Effective diffusion
coefficient ꢂ 10ꢁ4
(cm2 sꢁ1
)
(cm2 sꢁ1
)
Magnetic ux
intensity (mT)
CO
H2
CO
H2
0
0.89
1.75
2.33
1.84
3.30
4.83
9.57
6.71
4.29
8.49
11.30
8.92
15.97
23.41
46.32
32.51
20.8
25.1
27.4
Fig. 10 CO and H2 diffusion over 5Fe–5Co/ZSM-5 catalyst at 50 ꢀC.
3994 | RSC Adv., 2021, 11, 3990–3996
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eld were improved by approximately 2.6 and 2.9 times, Engineering (postdoc grant), Kasetsart University. The authors
respectively, compared to those without magnetic eld. This is would like to thank the Synchrotron Light Research Institute
in good agreement with the experimental results observed in (BL2.2: TR-XAS) for support in XAS measurements.
Fig. 10. As a result, it can be concluded that the application of
an external magnetic eld to catalytic CO hydrogenation over
a conned-space ZSM-5 zeolite based catalyst can facilitate the
synergy between the external magnetic eld and limited mass
References
transfer within zeolite cavities. These phenomena consequently
led to differences in effective diffusion abilities of CO and
hydrogen during the reaction within the catalyst pores, leading
to signicant improvement in CO conversion.
As the reactor system consisting an external magnetic eld in
cooperation with a conned-space zeolite catalyst can facilitate
different mass transfer abilities of reactant gases and products,
the potential application for reactive separation processes by
means of selective reactant and product mass transfers
designed for separation—selective catalytic conversion with
tailored reaction pathways are therefore able to provide
a potential challenge for larger—scale green and sustainable
chemical processes in the future.
1 H. Li, J. Wang, C. Chen, L. Jia, B. Hou and D. Li, RSC Adv.,
2017, 7, 9436–9445.
´
2 C. I. Mendez and J. Ancheyta, Catal. Today, 2020, 353, 3–16.
3 Z. Qi, L. Chen, S. Zhang, J. Sub and G. A. Somorjai, Appl.
Catal. Gen., 2020, 602, 117607.
4 W. Li, H. Wang, X. Jiang, J. Zhu, Z. Liu, X. Guo and C. Song,
RSC Adv., 2018, 8, 7651–7669.
5 H. Dong, M. Xie, J. Xu, M. Li, L. Peng, X. Guo and W. Ding,
Chem. Commun., 2011, 47, 4019–4021.
6 V. Benedetti, S. S. Ail, F. Patuzzi, D. Cristofori, R. Rauch and
M. Baratieri, Renewable Energy, 2020, 147, 884–894.
7 T. Numpilai, N. Chanlek, Y. Poo-Arporn, S. Wannapaiboon,
C.
K.
Cheng,
N. Siri-Nguan,
T.
Sornchamni,
P. Kongkachuichay, M. Chareonpanich, G. Rupprechter,
J. Limtrakulg and i Witoon, Appl. Surf. Sci., 2019, 483, 581–
592.
Conclusions
In this work, the external magnetic eld was applied for the rst
time for catalytic CO hydrogenation in a conventional reactor
packed with a conned-space 5Fe–5Co/ZSM-5 catalyst. It was
found that magnetic ux intensities at the catalyst bed in the
8 H. Song, Q. Zhao, X. Zhou, Z. Cao and M. Luo, Fuel, 2018,
229, 144–150.
9 B. Gu, A. Y. Khodakov and V. V. Ordomsky, Chem. Commun.,
2018, 54, 2345–2348.
¨
range of ꢁ20.8 and ꢁ25.1 mT with magnetic eld orientation of 10 H. Becker, R. Guttel and T. Turek, Catal. Sci. Technol., 2016,
N–S alignment could successfully promote the CO conversion
and CH4 selectivity by factors of 1.9 and 1.3 compared to those 11 J. Wang, H. Li, D. Li, J. P. den Breejen and B. Hou, RSC Adv.,
without magnetic eld, respectively. In addition, the observa- 2015, 5, 65358–65364.
tion on CO and H2 diffusivities over the 5Fe–5Co/ZSM-5 catalyst 12 A. Carvalho, M. Marinova, N. Batalha, N. R. Marcilio,
6, 275–287.
evidently conrmed the synergistic effect between magnetic
eld and limited mass transfer within zeolite cavities as external
A. Y. Khodakov and V. V. Ordomsky, Catal. Sci. Technol.,
2017, 7, 5019–5027.
magnetic eld could promote mass transfer ability and enhance 13 H. X. Vu, M. Schneider, U. Bentrup, T. T. Dang,
the catalytic activity with tailored reaction pathways. As a result,
B. M. Q. Phan, D. A. Nguyen, U. Armbruster and A. Martin,
the concepts of magnetic eld-assisted conned-space catalyst
Ind. Eng. Chem. Res., 2015, 54(6), 1773–1782.
utilization are therefore able to provide an innovation challenge 14 R. Liu, Z. Ma, J. D. Sears, M. Juneau, M. L. Neidig and
for green and sustainable chemical processes and separation M. D. Porosoff, J. CO2 Util., 2020, 41, 101290.
processes by means of selective reactant and product mass 15 C. Liu, Y. Chen, Y. Zhao, S. Lyu, L. Wei, X. Li, Y. Zhang and
transfers designed for selective catalytic conversion–separation
Ji. Li, Fuel, 2020, 263, 116619.
in the future.
16 G. H Yao, F. Wang, X. B Wang and K. T Gui, Energy, 2010, 35,
2295–2300.
17 W. Zhang, X. Wang and X. Fu, Chem. Commu., 2003, 2196–
2197.
Conflicts of interest
There are no conicts to declare.
18 A. N. Pour, J. Karimi, S. Taghipoor, M. Gholizadeh and
M. Hashemian, J. Iran Chem. Soc., 2017, 14, 1477–1488.
19 P. Nikparsa, A. Nikparsa and A. Mirzaei, Phys. Chem. Res.,
2020, 8, 645–656.
Acknowledgements
This work was nancially supported by the Program Manage- 20 J. Li, L. Zhou, Q. Zhu and H. Li, Ind. Eng. Chem. Res., 2013, 52,
ment Unit for Human Resources & Institutional Development, 6647–6654.
Research and Innovation [grant number B05F630097]; the 21 J. Li, J. Li, Q. Zhu and H. Li, Chem. Eng. J., 2018, 350, 496–506.
Research Network of NANOTEC (RNN), the Ministry of Science 22 B. Stuyven, Q. Chen, W. V. de Moortel, H. Lipkens, B. Caerts,
and Technology, Thailand; the Center for Advanced Studies in
Nanotechnology for Chemical, Food and Agricultural Indus-
tries, Kasetsart University; the Kasetsart University Research
and Development Institute (KURDI); and the Faculty of
A. Aerts, L. Giebeler, B. Van Eerdenbrugh, P. Augustijns,
G. Van den Mooter, J. Van Humbeeck, J. Vanacken,
V. V. Moshchalkov, J. Vermant and J. A. Martens, Chem.
Commun., 2009, 47, 47–49.
© 2021 The Author(s). Published by the Royal Society of Chemistry
RSC Adv., 2021, 11, 3990–3996 | 3995

View Article Online
RSC Advances
Paper
23 L. Chen, Q. Zhu, Z. Hao, T. Zhang and Z. Xie, Int. J. Hydrogen 28 W. Wannapakdee, C. Wattanakit, V. Paluka, T. Yutthalekha
Energy, 2010, 35(6), 8494–8502. and J. Limtrakul, RSC Adv., 2016, 6, 2875–2881.
24 S. Kiatphuengporn, P. Jantaratan, J. Limtrakul and 29 L. Niu, X. Liu, X. Wen, Y. Yang, J. Xu and Y. Li, Catal. Today,
M. Chareonpanich, Chem. Eng. J., 2016, 306, 866–875. 2020, 343, 101–111.
25 S. Kiatphuengporn, W. Donphai, P. Jantaratan, N. Yigit, 30 C. Sriakkarin, W. Umchoo, W. Donphai, Y. Poo-arporn and
¨
K. Fottinger, G. Rupprechter and M. Chareonpanich, J.
M. Chareonpanich, Catal. Today, 2018, 314, 114–121.
31 W. Donphai, N. Piriyawate, T. i Witoon, P. Jantaratana,
V. Varabuntoonvit and M. Chareonpanich, J. CO2 Util,
2016, 16, 204–211.
Clean. Prod., 2017, 142, 1222–1233.
26 W. Umchoo, C. Sriakkarin, W. Donphai, C. Warakulwit,
Y. Poo-arporn, P. Jantaratana, T. Witoon and
M. Chareonpanich, Energ. Convers. Manage., 2018, 159, 32 K. Oshima, T. Shinagawa, Y. Nogami, R. Manabe, S. Ogo and
342–352. Y. Sekine, Catal. Today, 2014, 232, 27–32.
27 B. Liu, Q. Duan, C. Li, Z. Zhu, H. Xi and Y. Qian, New J. 33 W. L. McCabe, J. C. Smith and P. Harriott, Unit Operations of
Chem., 2014, 38, 4380–4387.
Chemical Engineering, McGraw-Hill, New York, 7th edn, 2005.
34 J. W. Beeckman, Chem. Eng. Sci., 1990, 45, 2603–2610.
3996 | RSC Adv., 2021, 11, 3990–3996
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