CHEMCATCHEM
COMMUNICATIONS
DOI: 10.1002/cctc.201300547
A Highly Active Ni/ZSM-5 Catalyst for Complete
Hydrogenation of Polymethylbenzenes
Shi-Chao Qi,[a] Xian-Yong Wei,*[a] Zhi-Min Zong,[a] Jun-ichiro Hayashi,[b] Xin-Hua Yuan,[c] and
Lin-Bing Sun[d]
Highly active supported nickel catalysts (SNCs) play crucial
roles in many chemical processes, such as olefin hydrogena-
tion,[1] cross-coupling reaction,[2] stereoselective synthesis,[3]
electrochemistry,[4] and biochemistry.[5] Catalytic hydrogenation
of arenes was considered to be the criterion for evaluating the
activity of SNCs.[6] For instance, methanol-to-gasoline (MTG) is
an important process of energy conversion, but it normally
produces substantial amount of a heavy mixture (HM), which is
rich in polymethylbenzenes (PMBs).[7–11] It is extremely difficult
to hydrogenate PMBs, because increasing the number of
methyl groups severely reduces both the equilibrium and rate
constants of the hydrogenation.[1,6] Conventional methods of
catalyst preparation, such as impregnation, co-precipitation,
sol-gel, and in situ reduction,[12–15] are relatively tedious and no
reports have been issued on the hydrogenation of PMBs with
4–6 methyl groups. Metal carbonyls (MCs) can be decomposed
to fine metal particles at elevated temperatures and are there-
by ideal precursors of highly active metal particles,[16] e.g., Ni-
Cu surface alloys were prepared by decomposing nickel tetra-
carbonyl (NTC) on a copper substrate at 3028C.[17] Although
some attempts for preparing metallic catalysts using MCs have
been tried since 1980s,[18–21] the preparation of SNCs, which are
active enough to catalyze the hydrogenation of PMBs with 4–6
methyl groups, has not been successful, most likely becau-
se the boiling point (438C) of NTC is much lower than its de-
composition temperature and there is a decomposition-combi-
nation equilibrium (DCE) between NTC and its decomposition
products Ni and CO in a closed reactor.
Herein we report a new strategy for in situ preparation of
highly active SNCs by decomposing NTC at 1008C to highly
dispersive Ni onto ZSM-5. The decomposition was successively
conducted to destroy the DCE by releasing the resulting CO.
This strategy allows successful preparation of a highly active
SNC (i.e., Ni/ZSM-5), which exhibits dramatically high activity
for the hydrogenation of benzene, toluene, durene, and HM
from MTG. The operating conditions of the catalyst characteri-
zations are detailed in the Supporting Information.
As Figure 1 displays, a number of spherical particles with di-
ameter less than 100 nm adhere to the surface of ZSM-5. The
Figure 1. SEM image of Ni/ZSM-5.
existence of Ni, Si, Al, and O in the catalyst was confirmed
from EDS spectrum analysis (Figure S1). In Figure S1, a small
peak area of Ni indicates a relative low Ni load, which is ap-
proximately 6.2 wt% according to ICP-OES analysis (Table 1). In
Table 1, the Al content comes from the framework of ZSM-5
and the other metallic elements, except Ni, are probably due
to impurities in the parent zeolite.
[a] S.-C. Qi, Prof. X.-Y. Wei, Prof. Z.-M. Zong
Key Laboratory of Coal Processing and
Efficient Utilization (Ministry of Education)
China University of Mining & Technology
Xuzhou 221116 (P.R. China)
Fax: (+86)516-83884399
As shown in Figure 2, the average diameter of Ni clusters
supported on ZSM-5 is smaller than 100 nm, which corre-
sponds to the result given in Figure 1. Furthermore, in the
scope of HREM, most of Ni supported onto ZSM-5 does not
[b] Prof. J.-i. Hayashi
Division of Advanced Device Material
Institute for Materials Chemistry and Engineering
Kyushu University
6-1, Kasuga Koen, Kasuga, Fukuoka 816-8580 (Japan)
[c] Prof. X.-H. Yuan
Materials Institute
Table 1. Metallic element contents in the catalyst.
Jiangsu University
Zhenjiang 212013 (P.R. China)
Element
Content
[ppmw]
Element
Content
[ppmw]
[d] Prof. L.-B. Sun
State Key Laboratory of Materials-Oriented Chemical Engineering
Nanjing University of Technology
Nanjing 210009 (P.R. China)
Al
137200.0
62350.0
1695.0
Cr
218.4
76.2
70.9
9.7
Ni
Fe
Ca
Mn
Zn
Cu
Supporting information for this article is available on the WWW under
745.4
ꢀ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemCatChem 2013, 5, 1 – 5 1
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