Journal of Materials Science and Chemical Engineering, 2014, 2, 1-3
Published Online June 2014 in SciRes. http://www.scirp.org/journal/msce
http://dx.doi.org/10.4236/msce.2014.26001
How to cite this paper: Han, X.Y., Fang, K., Lin, M.G. and Sun, Y.H. (2014) Highly Dispersed Cu-Base Catalyst Derived from
Layered Double Hydroxides for CO Hydrogenation. Journal of Materials Science and Chemical Engineering, 2, 1-3.
http://dx.doi.org/10.4236/msce.2014.26001
Highly Dispersed Cu-Base Catalyst Derived
from Layered Double Hydroxides for CO
Hydrogenation
Xinyou Han1,2, Kegong Fang1, Minggui Lin1, Yuhan S un1,3
1State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan,
China
2University of the Chinese Academy of Sciences, Beijing, China
3Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, China
Received February 2014
Abstract
Highly dispersed Cu-base catalyst has been prepared via thermal decomposition of layered double
hydroxides precursors. The XRD pattern and the HRTEM images of the as prepared catalyst con-
firmed the high dispersion of Cu and Fe ions. Results show that the catalyst has a relatively high
selectivity of alkanes at low temperature.
Keywords
Highly Dispersed, LDHs, CO Hydrogenation, Cu Base
1. Introduction
Cu-based catalysts containing active metal toward Fischer-Tropsch synthesis such as Cu-Fe based catalyst, is
considered as one of the most promising catalysts for higher alcohols synthesis from syngas [1-3]. Most re-
searchers considered the synerg istic effect between Cu and Fe played a key role in the higher alcohol synth esis
(HAS) [4]. However, the copper sintering at higher temperature has a negative influence on the synergistic ef-
fect. In the layer structure of the layered double hydroxides (LDHs), metal ions mixed with each other homoge-
neously [5], which might facilitate the synergetic effect of the active metal particles and inhibit the sintering of
the metals. Thus, in this paper catalyst derived from layered double hydroxides containing highly dispersed Cu
has been prepared by hydrothermal method and its application in the CO hydration has been examined.
2. Experiments
Highly dispersed Cu-base catalyst w as prepared according to the reference [5] with some modification. In a typ-
ical process, 1.21 g Cu(NO3)2·3H2O, 2.02 g Fe(NO3)3·9H2O, 5 g Al(NO3)3·9H2O and 12.8 g Mg(NO3)2·6H 2O
were dissolved together in 400 mL deionized water (molar ratio, MII/MIII = 3), which was referred as solution
A. Solution B was the mixture of K2CO3 and KOH with concentration of 0.25 and 0.8 mol/L. Solutions A and B

X. Y. Han et al.
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were simultaneously added into a glass reactor under vigorous stirring at room temperature and a pH value of
9.5.
The slurry was aged at 393 K fo r 20 h, filtered off, and washed thoroughly with distilled water. The precipi-
tate was then dried at 353 K for 12 h and identified as CuFe-LDH. The layered structure of prepared CuFe-LDH
sample was confirmed by XRD (see Figure 1).
These Cu-containing layered double hydroxides were calcined at 573 K in a stationary air for 4 h and the
product catalysts were identified as CuFeMgAl. The catalytic performance was tested in a fixed-bed reactor.
3. Results and Discussions
The XRD patterns of the precursor before and after calcination are shown in Figure 1. The XRD patterns before
calcination illustrate the typical peaks for LDHs. Peaks at 11.6, 23.3, 34.7, 39.3, 46.7, 60.5, and 61.8 are ob-
served in the precursor, which are assigned to the (003), (006), (012), (015), (018), (110), and (113) diffractions
of LDHs.
Further more, from the XRD pattern no clear peaks of Cu , Fe or CuFe oxide species are found which mean
that the Cu and Fe ions are highly dispersed in the precursor. After calcination, peak at 13 was assigned as the
remain layered structure and peaks at 60.5 and 61.8 are the remain structure of LDHs within the layers which we
can also see at Figure 2(b).
Figure 2(a) shows the cross-section of layered platelet in CuFeMgA l, from which it can be found that the
layered structure of hydrotalcite. Agreed with the result of XRD pa ttern, no Cu or Fe oxide particles can be
found in the plates which indicate the highly dispersion of metal ions in the LDHs.
The catalytic performance of the catalyst towards CO hydrogenation was examined under the following reac-
tion conditions: 4.0 MPa, GHSV of 5000 h−1, n(H2)/n(CO) = 2.0 and the results are shown in Table 1. It could
be seen that the main products at low temperature was alkanes with selectivity of 93.8 wt.%. Along with the rise
of temperature, the selectivity of alkanes fall down and the selectivity of alcohols changed from 1.09 w t .% at
20 40 60 80
Intensity (a.u.)
2 theta (degree)
(a)
(113)
(110) (018)
(015)
(009) (006)
(b)
(003)
Figure 1. XRD patterns of the precursor before (a) and after
(b) calcina tion s.
Figure 2. Layered structure of the calcinlated sample, stand up (a) and lie down (b).

X. Y. Han et al.
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Table 1. Catalytic results of layered double hydroxides (LDHs) supported catalyst.
Catalyst T(K) CO conversion (%) STYROH Selectivity (wt.%) Alcohol distribution (wt.%)
(g/g/h) ROH CHn CO2 C1OH C2 + OH
CuFeMgAl
493 8.05 0.00 1.09 93.80 5.11 59.61 40.39
513 19.39 0.01 3.28 83.86 12.86 61.47 38.53
533 32.28 0.06 9.91 67.79 22.30 58.86 41.14
553 54.99 0.11 9.04 54.03 36.93 53.63 46.37
Reaction conditions: H2/CO = 2.0, GHSV = 5000 h−1, P = 4.0 MPa.
493 K to 9.91 w t.% at 533 K. And at 553 K the selectivity of alcohols slightly fell may be due to the sintering of
Cu.
4. Conclusion
In summary, this work confirmed that bimetallic highly dispersed Cu-base catalysts could be prepared via ther-
mal decomposition of layered double hydroxides precursors. This is attributed to the layered structure of hydro-
talcite which could efficiently inhibit the sintering of the Cu and Fe ions. Furthermore, at low temperature the
main products of the catalyst were alkanes and as temperature grows the selectivity of alcohols becomes higher.
References
[1] Lin, M., Fang, K., Li, D. and Sun, Y. (2008) CO Hydrogenation to Mixed Alcohols over Co-Precipitated Cu-Fe Cata-
lysts. Catalysis Communications, 9, 1869-1873. http://dx.doi.org/10.1016/j.catcom.2008.03.004
[2] Lin, M., Fang, K., Li, D. and Sun, Y. (2008) Phase Transformation in Cu-Fe Based Catalyst during CO Hydrogenation.
Chinese Journal of Catalysis, 29, 559-565.
[3] Fang, K., Li, D., Lin, M., Xiang, M., Wei, W. and Sun, Y. (2009) A Short Review of Heterogeneous Catalytic Process
for Mixed Alcohols Synthesis via Syn ga s . Catalysis Today, 147, 133-138.
[4] Gao, W., Zhao, Y.F., Liu, J.M., Huang, Q.W., He, S., L i, C.M., Zhao, J.W. and Wei, M. (2013) Catalytic Conversion
of Syngas to Mixed Alcohols over CuFe-Based Catalysts Derived from Layered Double Hydroxides. Catalysis Science
& Technology, 5, 1324-1332.
[5] Yuan, Z., Wang, L., Wang, J., Xia, S., Chen, P., Hou, Z. and Zheng, X. (2011) Hydrogenolysis of Glycerol over Ho-
mogenously Dispersed Copper on Solid Base Catalysts. Applied Catalysis B: Environmental, 101, 431-440.
http://dx.doi.org/10.1016/j.apcatb.2010.10.013