Nanosized CuO and ZnO Catalyst supported on honeycomb-typed monolith for hydrogenation of carbon dioxide to methyl alcohol

Article abstract of DOI:10.1166/jnn.2015.8337

The greenhouse effect of carbon dioxide (CO₂) has been recognized as one of the most serious problems in the world. Conversion of CO₂ to methyl alcohol (CH₃OH) was studied using catalytic chemical methods. Honeycomb-typed monolith used as catalyst support was 400 cell/inch². Pretreatment of the monolith surface was carried out by thermal treatment and acid treatment. Monolith-supported nanosized CuO-ZnO catalysts were prepared by wash-coat method. The prepared catalysts were characterized by using SEM, TEM, and XRD. The catalytic activity for CO₂ hydrogenation to CH₃OH was investigated using a flow-type reactor with varying reaction temperature, reaction pressure and contact time. Conversion of CO₂ was increased with increasing reaction temperature, but selectivity to CH₃OH was decreased. Optimum reaction temperature was about 250°C under 20 atm. Because of the reverse water gas shift reaction.

Full text of DOI:10.1166/jnn.2015.8337

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Nanoscience and Nanotechnology
Vol. 15, 570–574, 2015
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Nanosized CuO and ZnO Catalyst Supported on
Honeycomb-Typed Monolith for Hydrogenation
of Carbon Dioxide to Methyl Alcohol
Chul-Min Park1, Won-Ju Ahn1, Woong-Kyu Jo1, Jin-Hun Song1, Chang-Yeop Oh1,
Young-Shin Jeong1, Min-Chul Chung1, Kwon-Pil Park1, Ki-Joong Kim2, Woon-Jo Jeong3,
Bo-Kyun Sohn4, Sang-Chul Jung5, Do-Jin Lee6, Byeong-Kwon Ahn7, and Ho-Geun Ahn1ꢀ∗
1Department of Chemical Engineering, Sunchon National University, Suncheon, Jeonnam 540-742, Republic of Korea
2School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis,
Oregon 97331, United States
3Department of Information Communication, Chosun College University of Science and Technology, 290 Seosuk-dong,
Dong-gu, Gwangju 501-744, Republic of Korea
4Department of Biological Environment, Sunchon National University, Suncheon, Jeonnam 540-742, Republic of Korea
5Department of Environmental Engineering, Sunchon National University, Suncheon, Jeonnam 540-742, Republic of Korea
6Department of Agricultural Education, Sunchon National University, Suncheon, Jeonnam 540-742, Republic of Korea
7Department of Environmental Health, Chodang University, Muangun, Jeonnam 534-701, Republic of Korea
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The greenhouse effect of carbon dioxide (CO2ꢀ has been recognized as one of the most seri-
Copyright: American Scientific Publishers
ous problems in the world. Conversion of CO2 to methyl alcohol (CH3OH) was studied using cat-
alytic chemical methods. Honeycomb-typed monolith used as catalyst support was 400 cell/inch2.
Pretreatment of the monolith surface was carried out by thermal treatment and acid treatment.
Monolith-supported nanosized CuO–ZnO catalysts were prepared by wash-coat method. The pre-
pared catalysts were characterized by using SEM, TEM, and XRD. The catalytic activity for CO2
hydrogenation to CH3OH was investigated using a flow-type reactor with varying reaction tempera-
ture, reaction pressure and contact time. Conversion of CO2 was increased with increasing reaction
temperature, but selectivity to CH3OH was decreased. Optimum reaction temperature was about
ꢀ
250 C under 20 atm. Because of the reverse water gas shift reaction.
Keywords: Honeycomb-Typed Monolith, CuO, ZnO, Carbon Dioxide, Hydrogenation, Methyl
Alcohol.
1. INTRODUCTION
for formaldehyde, methyl tert-butyl ether and several
solvents.3 CH3OH can be also converted to olefins by
recently developed processes.4
The greenhouse effect of carbon dioxide (CO2ꢀ has been
recognized as one of the most serious problems in the
world.1 Synthesis of valuable chemicals by CO2 hydro-
genation has received much attention as one of the
technologies to solve the CO2 problem in recent year.
Among them, CH3OH synthesis is one of most attractive
applications.
CH3OH is one of the basic intermediates in the chem-
ical industry and is also being used as a fuel additive
and as a clean burning fuel.2 It is the starting point
Catalytic monoliths consist of catalytic particles sup-
ported on a structured support made up of parallel chan-
nels of either a metal or a ceramic.5 Ceramic or metallic
foams also represent (more randomly) structured supports
with similar properties and applications, and are some-
times also referred to as monoliths. Ceramic (channeled)
monoliths are usually produced by extrusion, while metal-
lic monoliths are conventionally made from rolled layers
of corrugated and flat sheets.5 Catalytic layer is often pre-
pared by wash coating the monoliths with a high surface
∗Author to whom correspondence should be addressed.
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J. Nanosci. Nanotechnol. 2015, Vol. 15, No. 1
1533-4880/2015/15/570/005
doi:10.1166/jnn.2015.8337

Park et al.
Nanosized CuO and ZnO Catalyst Supported on Honeycomb-Typed M for Hydrogenation of CO2 to CH3OH
Figure 1. Schematic diagram of experimental apparatus for conversion of CO2 to CH3OH.
area support and subsequent impregnation with the active
metals.
Honeycomb monolith (400 cell/inch2, Ordeg) was cut-
ted to be diameter 1.5 cm (2.4 g). Precursor solution of
Cu(NO ꢀ ·3H O and Zn(NO ꢀ ·6H O were added to dis-
In this study, monolith (M) supported CuO and ZnO
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3
2
3
2
2
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tilled water. Precursor concentrations in the solution were
catalysts were prepared by wash-coat method. After char-
actering the catalysts by means of some instrumental tech-
niques, the hydrogenation activity for CO2 to CH3OH was
investigated.
Copyright: American Scientific Publishers
varied. After dipping the monolith in the solution for
30 min, it was slowly drawn up at a rate 6 cm h−1. CuO–
ZnO/M catalyst was obtained by repeated calcinations in
ꢀ
air at 400 C for 3 h.
The prepared catalysts were characterized by using SEM
(S-3500N, Hitachi), BET specific surface area (ASAP-
2010, Micromeritics), TEM (JEM-2100F, Jeol), and X-ray
diffraction (XRD, D/Max 2200, Rigaku). The chemical
composition of representative surface particles was ana-
lyzed by energy dispersive spectroscopy (EDS).
2. EXPERIMENTAL DETAILS
2.1. Catalysts Preparation
The CuO–ZnO/M catalysts (CuO; 44.7 wt%, ZnO;
55.3 wt%) were prepared by wash-coat method.
2.2. Catalytic Activity
The prepared CuO–ZnO/M catalyst was tested for CH3OH
synthesis using a fixed-bed down flow reactor. Figure 1
shows experimental apparatus for hydrogenation of CO2
to CH3OH. The catalyst was loaded in the reactor and
was reduced in a gas stream of H2 (40 mL min−1ꢀ at
ꢀ
300 C for 3 h. The temperature of preheater and reactor
was controlled by PID controller, and total reaction pres-
sure was regulated with a back-pressure-regulator. After
cooling the catalyst bed to the reaction temperature, reac-
tion gas (26 mol%-CO2, 73 mol%-H2ꢀ were fed at 60 mL
min−1 using a mass flow controller. The exit line from
the reactor to the gas sampler was heated to prevent con-
densation of any volatile products. Feed and product gas
mixtures were analyzed by using the gas chromatograph
(GC-14B, Shimadzu) with a thermal conductivity detector.
Figure 2. XRD patterns of CuO–ZnO/M catalyst prepared using
the solution with different precursor concentrations. (a) 13.6 w/v%,
(b) 25.7 w/v%.
J. Nanosci. Nanotechnol. 15, 570–574, 2015
571

Nanosized CuO and ZnO Catalyst Supported on Honeycomb-Typed M for Hydrogenation of CO2 to CH3OH
Park et al.
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Copyright: American Scientific Publishers
Figure 3. SEM images and EDS spectra of CuO–ZnO/M catalysts with various impregnation numbers. (a) No coated, (b) once, and (c) twice.
J. Nanosci. Nanotechnol. 15, 570–574, 2015
572

Park et al.
Nanosized CuO and ZnO Catalyst Supported on Honeycomb-Typed M for Hydrogenation of CO2 to CH3OH
(a)
(b)
Figure 4. TEM images of CuO–ZnO/M catalyst with various pre-
cursor concentrations (right images show magnified TEM images).
(a) 25.7 w/v% and (b) 73.6 w/v%.
Two serial columns (Porapak-Q and MS-13X) were con-
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nected to a 10-way valve for on-line sampling.
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Copyright: American Scientific Publishers
3. RESULTS AND DISCUSSION
Figure 2 shows the XRD patterns of CuO–ZnO/M catalyst
prepared using the solution with different precursor con-
centrations. Characteristic peaks of CuO are 2ꢁ = 43ꢂ3ꢀ,
50.7ꢀ, 72.9ꢀ, and those of ZnO are 2ꢁ = 36ꢂ9ꢀ, 42.8ꢀ, 62.5ꢀ,
74.3ꢀ, 77.43ꢀ. It was confirmed that the CuO and ZnO on
both catalysts prepared by wash-coat method were well
formed on ceramic monolith.
Figure 3 shows SEM images and EDS spectra of
CuO–ZnO/M catalyst with various impregnation numbers.
The particles of CuO and ZnO were coated on the mono-
lith, and it was confirmed that the particles were composed
of CuO and ZnO from EDS spectra.
Figure 4 shows TEM images of CuO–ZnO/M catalyst
with various precursor concentrations. The particles of
CuO and ZnO were well dispersed to be nanosized. It was
confirmed that the particles in both cases were composed
of CuO and ZnO confirmed.
Figure 5. Effect of time on stream on CO2 conversion (a), CH3OH
selectivity (b) and CH3OH yield (c) over CuO–ZnO/M catalyst with var-
ious impregnation numbers.
temperature and reaction pressure were 250 ꢀC and 20 atm,
respectively.
Figure 6 shows effect of reaction temperature on CO2
conversion, selectivity and yield of CH3OH over CuO–
ZnO/M catalyst. CuO and ZnO was once coated with pre-
cursor solution of 25.7 w/v%. With increasing reaction
temperature, CO2 conversion was increased, but selectivity
and yield of CH3OH was decreased. Optimum reaction
Figure 5 shows effect of time on stream on CO2 conver-
sion, selectivity and yield of CH3OH over CuO–ZnO/M
catalyst with various impregnation numbers. The mono-
ꢀ
lith was pretreated at 600 C. Cell of monolith can be
clogged up with catalyst materials if impregnation number
is increased. Conversions for CO2 hydrogenation were all
more or less similar. Selectivity of CH3OH was increased
with decreasing the impregnation number. The reaction
ꢀ
temperature was about 250 C under 20 atm because of
the reverse water gas shift reaction.
J. Nanosci. Nanotechnol. 15, 570–574, 2015
573

Nanosized CuO and ZnO Catalyst Supported on Honeycomb-Typed M for Hydrogenation of CO2 to CH3OH
Park et al.
with increasing reaction temperature, but CH3OH selec-
tivity was decreased. Optimum reaction temperature was
ꢀ
about 250 C under 20 atm because of the reverse water
gas shift reaction. Maximum CH3OH yield over CuO–
ꢀ
ZnO/M at 250 C were ca. 5.1% at 20 atm.
Acknowledgment: This research was financially sup-
ported by the Ministry of Education, Science Technol-
ogy (MEST) and National Research Foundation of Korea
(NRF) through the Human Resource Training Project for
Regional Innovation.
References and Notes
1. M. Takeuchi, M. Saito, T. Fujitani, T. Watanabe, and Y. Kanai,
Abstract of ICCDU-III, University of Oklahoma (1995).
2. M. L. Kliman, Energy 8, 859 (1983).
Figure 6. Effect of reaction temperature on CO2 conversion, selectivity
and yield of CH3OH over CuO–ZnO/M catalyst.
3. S. Lee, Methanol Synthesis Technology, CRC Press, Inc., Boca Raton,
FL (1990).
4. D. Chen, A. Gronvold, K. Moljord, and A. Holmen, Ind. Eng. Chem.
Res. 46, 4116 (2006).
5. A. Cybulski and J. A. Moulijn, Structured Catalysts and Reactor, CRC
Press LLC, NY (2006).
4. CONCLUSION
The catalytic activity for CO2 hydrogenation to CH3OH
over CuO–ZnO/M catalysts was investigated using a
flow-type reactor. The particles of CuO and ZnO were
well coated on monolith. Conversion of CO2 was increased
Received: 22 March 2013. Accepted: 22 April 2013.
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574
J. Nanosci. Nanotechnol. 15, 570–574, 2015