N-Doped carbon encapsulated molybdenum carbide as an efficient catalyst for oxidant-free dehydrogenation of alcohols

Article abstract of DOI:10.1039/c7ta04763k

We report molybdenum carbide (Mo₂C) encapsulated in N-doped carbon as an efficient and stable catalyst for oxidant-free dehydrogenation of alcohols, prepared by anion exchange of H₃PMo₁₂O₄₀ (PMo) with an ionic copolymer (DIM-AN) of dicationic imidazole ionic liquid and acrylonitrile, followed by a two-step carbonization at 400 °C in air and 800 °C in Ar. The synthesized catalyst (PMo@DIM-AN_400/800) exhibits outstanding catalytic activity and selectivity for dehydrogenation of various alcohols under oxidant-free conditions and can be steadily reused at least five times for dehydrogenation of benzyl alcohol without changing its crystalline structure. The characterizations and comparative experimental results demonstrate that the active sites for dehydrogenation stem from the Mo₂C, as well as the abundant N atoms in the carbon shell, which contribute to the enhancement of catalytic performance. The strategy for the preparation of such N-doped carbon encapsulated Mo₂C using polyoxometalate-based ionic hybrids as precursors may open up new opportunities for exploring more transition-metal carbides for more catalytic applications.

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ISSN 2050-7488
PAPER
Kun Chang, Zhaorong Chang et al.
Bubble-template-assisted synthesis of hollow fullerene-like
MoS2 nanocages as a lithium ion battery anode material
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Graphical Abstract
N-doped Carbon Encapsulated Molybdenum Carbide as Efficient
Catalyst for Oxidant-Free Dehydrogenation of Alcohols
Yan Leng*, Jingjing Li, Chenjun Zhang, Pingping Jiang, Yue Li, Yuchen Jiang, Shengyu Du
The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical and Material
Engineering, Jiangnan University, Wuxi 214122, China; Fax: +86-510-85917763; Tel: +86-510-85917090;
E-mail: yanleng@jiangnan.edu.cn
Molybdenum carbide encapsulated in N-doped carbon was synthesized and used as a efficient
heterogeneous catalyst for oxidant-free dehydrogenation of alcohols.

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N-doped Carbon Encapsulated Molybdenum Carbide as
Efficient Catalyst for Oxidant-Free Dehydrogenation of
Alcohols
Received 00th January 20xx,
Accepted 00th January 20xx
DOI: 10.1039/x0xx00000x
Yan Leng*, Jingjing Li, Chenjun Zhang, Pingping Jiang, Yue Li, Yuchen Jiang, Shengyu Du
www.rsc.org/
Abstract: We report the molybdenum carbide (Mo2C) encapsulated in N-doped carbon as an efficient and stable catalyst
for oxidant-free dehydrogenation of alcohols, prepared by anion exchange of H3PMo12O40 (PMo) with ionic copolymer
(DIM-AN) of dicationic imidazole ionic liquid and acrylonitrile, followed by a two-step carbonization at 400 °C in air and
800 °C in Ar, respectively. The synthesized catalyst (PMo@DIM-AN400/800) exhibits outstanding catalytic activity and
selectivity for dehydrogenation of various alcohols under oxidant-free conditions, and can be steadily reused at least five
times for dehydrogenation of benzyl alcohol without changing its crystalline structure. The characterizations and
comparison experiments results demonstrate that the active sites for dehydrogenation stem from the Mo2C, as well as the
abundant N atoms in the carbon shell, which contribute to the enhancement of catalytic performance. The strategy for the
preparation of such N-doped carbon encapsulated Mo2C using polyoxometalates-based ionic hybrids as precursors may
open up new opportunities for exploring more transition-metal carbides for more catalytic applications.
Transition metal carbides (TMC), especially molybdenum (Mo)
carbides (MoCx), have aroused ever growing interest as high-
Introduction
Dehydrogenation of alcohols to carbonyl compounds is one of
the most essential transformations in synthetic chemistry.
Traditionally, stoichiometric amounts of oxidants (e.g., molecular
oxygen (O2), dichromate, H2O2, or permanganate) are employed to
achieve this transformation.[1-2] However, these reagents are often
hazardous and genreate a huge amount of wastes or undsirable
byproducts. With the increasing environmental and atom economy
concerns, the oxidant-free dehydrogenation of alcohols is proposed
as a promising transformation to overcome the above problems.[3]
Up to now, lots of catalytic systems based on noble metals such as
Au, Ru, Rh, Ag, and Pd, have been developed for this reaction.[4-8]
Although the oxidation method itself is simple and clean, these
noble metals used have disadvantages in terms of toxicity, high
cost, or need for acid/base additives to improve the catalytic
activity. Therefore, significant efforts have been devoted to the
development of oxidant-free dehydrogenation catalysts based on
earth-abundant metals.[9-10]
performance catalysts due to their chemical stability, good
electrical conductivity, and low cost.[11-13] They showed comparable
catalytic activities towards platinum-based catalysts in hydrogen
evolution of water,[14] hydrogenolysis of hydrocarbons,[15]
hydrodesulphurization and hydrodenitrogenation of fuels,[16] and
ammonia synthesis/decomposition.[17] Recently, MoCx have also
been explored as promising heterogeneous non-noble metal
catalysts for oxidant-free dehydrogenation of alcohols.[18] The
catalytic properties of MoCx are closely related to their
construction, shape, and crystalline structure. Generally, the
reduction and carburization of metallic oxide by hydrocarbon-
hydrogen mixtures at high temperatures is the commonly used
synthetic strategy for synthesis of MoCx.[19-20] However, this strategy
is not easy to control the shape and crystalline structure of MoCx,
and this may lead to the substantial enhancement of catalytic
activities.
Polyoxometalates (POMs), a unique class of bulky clusters of
transition metal oxide anions, display wide variety of composition
and structure.[21,22] Recently, POMs have been utilized as precursors
to fabricate TMC.[23-26] For example, CoMoP@C composite with
remarkable hydrogen evolution reaction performance has been
fabricated by pyrolysis of mixture of POMs with dicyandiamide.[27]
Another example is using phosphomolybdic acid (PMo12) to initiate
the polymerization of polypyrrole (PPy) to produce N,P-doped Mo2C
The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education,
School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122,
Jiangsu, China. E-mail: yanleng@jiangnan.edu.cn
Fax: +86-510-85917763; Tel: +86-510-85917090
Electronic Supplementary Information (ESI) available: [details of any
†
supplementary information available should be included here]. See
DOI: 10.1039/x0xx00000x
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nanocrystals for the hydrogen evolution reaction.[28] Actually, POMs
can easily combine with various N-containing organic precursors for
the construction of various hybrid materials.[29] A topic of interest in
this context is the design of POM-based ionic hybrids by anion
exchange of POM with ionic liquids (ILs) or poly(ionic liquids) for
organic synthesis.[30] We have prepared a series of functional POM-
based ionic hybrids, and the resulting ionic solids were turned out
to be effective heterogeneous catalysts for many acid-catalyzed or
oxidative organic transformations.[31-33] On the other hand, ILs and
ionic copolymers are ideal precursors for the preparation of carbon
materials, owning to their special features of high thermal stability,
easily shaping, and the variety of structures available.[34] In
particular, the presence of nitrile functional groups in ionic
compounds can undergo cross-linking reactions,[35-36] which is key
to attain various N-doped carbon materials (CN), and can also
improve the electric and catalytic performance of CN-supported
catalysts. We thus assumed that the in situ carbonization of POM-
based ionic hybrids can be especially feasible and advantageous for
producing of uniform distributed TMC within the CN derived from
organic ionic cations. To the best of our knowledge, MoCx have not
been previously prepared with a poly(ionic liquids) modified POM
hybrid as the precursor.
Scheme 1. Schematic of the fabrication process of N-
doped carbon encapsulated molybdenum carbide
(PMo@DIM-AN400/800).
Herein, we rationally designed and synthesized N-doped carbon
encapsulated molybdenum carbides (Mo2C) by carbonization of
H3PMo12O40 (PMo)-based ionic copolymer (DIM-AN) containing
dicationic imidazole IL and acrylonitrile (PMo@DIM-AN). During the
carbothermal treatment, the organic DIM-AN outside the PMo can
be easily converted into N-doped carbon shell through crosslinked
polymerization and carbonization. Meanwhile, PMo decomposed
and in situ generated Mo2C, which encapsulated in the N-doped
carbon shell. The present synthetic method relies on the
carbonization temperature and functional ―C≡N groups in the ionic
polymer that ensure the hybrid PMo@DIM-AN convert into a core-
shell catalyst structure. Systematic catalysis tests in the oxidant-free
dehydrogenation of alcohols reveal that the catalyst PMo@DIM-
AN400/800 afford highly efficient and recyclable catalytic activities
over various substrates.
μm). XPS was conducted with a PHI 5000 Versa Probe X-ray
photoelectron spectrometer equipped with an AlKa radiation
source (1486.6 eV). The C 1s peak at BE= 285.2 eV was used as a
reference for the BE values. Raman experiments were performed
using a PerkinElmer-Raman Station 400F spectrometer equipped
with a liquid N2 cooled charge-coupled device detector and a
confocal microscope. A 350 mW near-infrared 785 nm laser was
used for analysis under ambient conditions. TGA was performed in
a STA409 instrument in N2 at a heating rate of 10 °C /min.
Catalyst preparation
Synthesis of IL
Experimental section
1,4-bis(bromomethyl)benzene (0.04 mol, 3.76 g), 1-
vinylimidazole (0.02 mol, 5.28 g), and chloroform (50 mL) were
added into a 100 mL round-bottom flask. The mixture was heated
to 50 °C with stirring for 24 h. After completion, the produced white
solid powder was filtered and washed with diethyl ether for several
times, and then dried at 80 °C in vacuum. 1H NMR (4 MHz, D2O,
TMS) δ (ppm) = 5.37 (m, 2H, CH), 5.44 (s, 4H, CH2), 5.74 (m, 2H, CH),
7.06 (m, 2H, CH), 7.47 (s, 4H, CH), 7.53 (s, 2H, CH), 7.75 (s, 2H, CH),
9.06 (s, 2H, CH) (Figure S1, ESI).
Characterization
1H NMR spectra was measured with a Bruker DPX 4 spectrometer
at ambient temperature in D2O using TMS as internal reference.
Fourier transform infrared (FT-IR) spectra were recorded on a
Nicolet 360 FT-IR instrument (KBr discs) in the 4000-500 cm-1
region. SEM image was performed using a HITACHI S-48 field-
emission scanning electron microscope. XRD data were collected on
the Bruker D8 Advance powder diffractometer using Ni-filtered Cu
Kα radiation source at 40 kV and 20 mA, from 3 ° to 90 ° with a scan
rate of 4 °/min. TEM images were obtained with a JEOL JEM-2100
electron microscope operated at 200 Kv. The coupled products
were analyzed by gas chromatograph (GC, SP-6890A) equipped with
a FID detector and a capillary column (SE-54 30 m × 0.32 mm × 0.25
Synthesis of PMo@DIM-AN
The ionic copolymer DIM-AN was prepared via the
copolymerization of DIM and acrylonitrile (AN) using
azodiisobutyronitrile (AIBN) as initiator. In a typical synthesis, DIM
(1.0 g), AN (3.0 g), and AIBN (0.1 g) were dissolved in a mixture
solvent (ethanol 40 mL and water 5 mL). The mixture was stirred at
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(A)
65 °C for 24 h. After cooling to room temperature, the precipitate
was separated by centrifugation, washed with ethanol for three
times, and dried at 80 °C overnight to afford the ionic copolymer
DIM-AN. Subsequently, DIM-AN (2.0 g) was distributed in DMF (30
mL), then, the aqueous solution of H3PMo12O40 (1.0 g) was added
slowly into it. The mixture was stirred at room temperature for 24
h. On completion, the mixture solution was poured slowly into a
large amount of ethanol for precipitation, and the precipitate was
washed with ethanol for several times and dried at 80 °C in vacuum
to afford the PMo@DIM-AN.
(B)
873
(a)
100
80
2
1
0
1065
965
2800-3000
2247
809
(b)
1200
(c)
1000-1200
1630
(d)
60
3500 3000
2000
1000
200
400
600
)
800
Wavemunber(cm-1)
Temperature(
Figure 1. (A) FTIR spectra of (a) PMo@DIM-AN, (b) PMo@DIM-
AN400, (c) PMo@DIM-AN400/800, and (d) PMo@DIM-AN800; (B) TGA
curves of PMo@DIM-AN.
Synthesis of PMo@DIM
DIM (2.0 g) and AIBN (0.06 g) were dissolved in a mixture solvent
(ethanol 40 mL and water 5 mL). The solution was stirred at 70 °C Results and discussion
for 24 h. After cooling to room temperature, the solvent was
Preparation and characterization of catalysts
removed by rotary evaporation, and the residue was washed with
ethanol for three times, and dried at 80 °C overnight to afford the
ionic polymer of DIM. Then, DIM polymer (2.0 g) was dissolved in
water (15 mL). The aqueous solution of H3PMo12O40 (1.0 g) was
added slowly into the DIM solution, and the precipitate was formed
immediately. After stirring at room temperature for 1 h, the
precipitate was filtered out, washed with ethanol for several times,
dried at 80 °C in vacuum to give the product PMo@DIM.
The N-doped carbon encapsulated molybdenum carbides was
synthesized as shown in Scheme 1. By using PMo12O40 (PMo)-
based ionic copolymer (PMo@DIM-AN) as the precursor, the
pyrolysis treatment carbonized the hybrid DIM-AN into N-doped
3-
carbon, and simultaneously converted PMo12O40 into Mo2C via a
carbothermal reduction. Pyrolyzation yield of PMo@DIM-AN400/800
is about 40 wt %. For comparison, the samples PMo@DIM-AN400
(pyrolyzed only at 400 °C), PMo@DIM-AN800 (pyrolyzed only at 800
°C), and PMo@DIM400/800 (acrylonitrile free) were also prepared
based on the similar method.
Synthesis of PMo@DIM-AN400, PMo@DIM-AN400/800
PMo@DIM-AN800, and PMo@DIM400/800
,
The as-prepared hybrid PMo@DIM-AN was put into a muffle and
stabilized at 400 °C for 2 h under air with a heating rate of 5 °C /min
to give the PMo@DIM-AN400 sample. PMo@DIM-AN400 was further
pyrolyzed in a tube furnace at 800 °C for 2 h in an argon flow with
heating rate of 5 °C /min, and the product PMo@DIM-AN400 was
The fourier transform infrared (FTIR) spectra of PMo@DIM-AN in
Figure 1A exhibits the characteristic bands at 1065 (P-Oa), 965
(Mo=Od), 873 (Mo-Ob-Mo) and 809 cm-1 (Mo-Oc-Mo) assigned to
3-
the Keggin structure of PMo12O40 and the bands at 2247 (―C≡N)
and 2800-3000 cm-1 (―C-H) assigned to the organic copolymer
groups (curve a). After the PMo@DIM-AN calcined at a moderate
temperature of 400 °C in the air (curve b), the keggin peaks are
preserved in the FTIR spectrum of PMo@DIM-AN400. However, the
peaks assigned for organic species at 2247 and 2800-3000 cm-1 are
disappeared, and the strong signals at 1200-1630 cm-1 associated to
C=N/C=C bonds are emerged for PMo@DIM-AN400, indicating that
the carbonization treatment has converted the organic polymer of
DIM-AN into carbon nitride matrix. With the further pyrolysis
treatment at 800 °C (curve c), Keggin peaks are disappeared for
PMo@DIM-AN400/800. This is mostly ascribed to the decomposition
achieved. PMo@DIM400/800, DIM-AN400/800, and DIM400/800 were
prepared based on the similar method using PMo@DIM, DIM-AN,
or DIM as the precursor. Additionally, PMo@DIM-AN800 was
synthesized by directly calcination of PMo@DIM-AN in a tube
furnace at 800 °C as described above.
Catalytic test
The catalytic activity was evaluated in a 25 mL round bottomed
flask with nitrogen ball protection. In a typical experiment, catalyst
(0.05 g), benzyl alcohol (2 mmol), dimethyl sulfoxide (DMSO, 4 mL)
were added into the flask. After purging pretreatment of flask with
nitrogen, nitrogen ball was installed. The mixture solution was
heated to 120 °C and stirred for 4 h. After the reaction, the solid
catalyst was filtrated out, and the liquid was analyzed by a gas
chromatograph (GC, SP-6890A) equipped with a FID detector and a
capillary column (SE-54 30 m × 0.32 mm × 0.25 μm). The solid
catalyst was washed, dried at 800 °C, and directly reused in the next
run. Besides benzyl alcohol, various aromatic alcohols and alkyl
alcohols were tested as the substrates to examine the catalytic
3-
of PMo12O40 anions and its reconstructed with carbon nitride
matrix to form Mo2C. If the PMo@DIM-AN was directly carbonized
at 800 °C (curve d), characteristic peaks attributed to molybdenum
oxides (1000-1200 cm-1) are observed for PMo@DIM-AN800 due to
the decomposition of PMo12O403-. Moreover, the intensities for the
peaks of 1200-1630 cm-1 (C=N/C=C) are significant decreased, which
can be attributed to the condensation of the carbon nitride matrix
with release of nitrogen and hydrogen.
Thermog-ravimetric analysis (TGA) was carried out to detect the
carbonization process of PMo@DIM-AN. As shown in Figure 1B, two
distinct decomposition steps were occurred. The first stage ranging
activity of PMo@DIM-AN400/800
.
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(A)
39.4
34.4
38.0
61.6
74.8
52.3
(a)
8
(b)
(c)
27.3
23.5
12.8
38.9
25.7
(d)
20
40
60
80
2-Theta (degree)
Figure 3. SEM images of (A) PMo@DIM-AN400
PMo@DIM-AN400/800 (C) PMo@DIM-AN800 and (D)
PMo@DIM400/800
, (B)
(B)
D
,
,
1318
G
820
1596
.
992
(a)
structure of PMo was appeared (curve c), implying that the
pyrolysis treatment destroyed the organic groups, and the crystal
structure of PMo turned to be apparent. With the following
pyrolysis treatment at 800 °C, PMo@DIM-AN400/800 clearly displays a
set of diffraction peaks at 34.4, 38.0, 39.4, 52.3, 61.6, and 74.8°,
corresponding to the typical hexagonal structure of Mo2C crystals
(curve a).[37-39] However, only wide diffraction peaks located at 26.2°
was observed for PMo@DIM-AN800 (curve b). Moreover, in the XRD
pattern of AN-free sample PMo@DIM400/800 (Figure S2, ESI),
characteristic diffraction peaks located at 25.8°, 36.8°, and 53.2° are
ascribed to MoO2, and the peaks located at 23.4°, 36.8° matches
well with the orthorhombic MoO3 structures. It is thus suggested
that both the two-step pyrolysis treatment and the existence of
acrylonitrile are extremely essential for the generation of Mo2C.
(b)
(c)
(d)
500
1000
1500
2000
2500
Raman shift (cm-1)
Figure 2. (A) XRD patterns of (a) PMo@DIM-AN400/800, (b)
PMo@DIM-AN800, (c) PMo@DIM-AN400, (d) PMo@DIM-
AN; (B) Raman patterns of (a) PMo@DIM-AN400/800, (b)
PMo@DIM-AN800, (c) PMo@DIM-AN400, (d) PMo@DIM-
AN.
Raman spectroscopy gives a more favorable characterization of
the transformation of the carbon phase and formation of Mo2C in
samples. As shown in Figure 2B, in comparison with the Raman
spectrum of PMo@DIM-AN (curve d), two peaks located at 1318
and 1596 cm−1 represent the D and G bands of graphitic carbon,
respectively, were monitored for PMo@DIM-AN400. In the spectrum
of PMo@DIM-AN400/800, the intensity of D peak decreased, and the
new peaks belong to Mo2C crystals at 992 and 820 cm−1 are
occurred.[40] In contrast, there are no signals assigned to Mo2C were
observed in the Raman spectrum of PMo@DIM-AN800 (cure b).
Moreover, the spectrum of PMo@DIM400/800 exhibits the
characteristic peaks for MoOx (Figure S3, ESI). The phenomena of
Raman spectra are in accordance well with the observations in XRD
patterns.
from 300 to 500 °C, which was accompanied by a wide endothermal
peak around 380 °C, indicating the thermal degradation of organic
polymer backbones to carbon nitride matrix and the removal of H2O
and CO2. The second-stage between 500 to 700 °C can be attributed
3-
to the decomposition of PMo12O40 into P-, Mo- based species and
its reconstructed with carbon nitride matrix to form Mo2C and
graphitized structure of carbon material. Therefore, the variation of
TG pattern is in accordance with the FTIR results showing the hybrid
PMo@DIM-AN changing from carbonization of organic species for
PMo@DIM-AN400 to the disappeared Keggin structure of
PMo@DIM-AN400/800
.
The crystal structures of these samples are investigated by X-ray
diffraction (XRD) (Figure 2A). The XRD pattern of PMo@DIM-AN
reveals an amorphous organic-inorganic hybrid material (curve d).
After pyrolysis at 400 °C in the air, the broad diffraction peak at 8°
was disappeared for PMo@DIM-AN400 and some weak diffraction
peaks (12.8, 23.5, 25.7, 27.3, and 38.9°) assigned to Keggin
The pyrolysis temperature and the composition of ionic
copolymer have a significant influence on the morphologies of
synthesized catalysts. The hybrid PMo@DIM-AN is amorphous
aggregated solid blocks with particle sizes of 0.2-0.5 μm (Figure S4,
ESI). After the pyrolysis at 400 °C in air, PMo@DIM-AN400 preserved
the intact structure, but the morphology of solid blocks was shrunk
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Figure 4. TEM images of (A and D) PMo@DIM-AN400/800, (B) PMo@DIM-AN400, (C) PMo@DIM-AN800; HTEM images of PMo@DIM-
AN400/800 (E and F).
and the surface became smooth (Figure 3A). Interestingly, with the AN400/800, PMo@DIM-AN800, and PMo@DIM400/800. The XPS spectra
further pyrolysis at 800 °C in Ar, the SEM image of PMo@DIM- indicates the existence of C, Mo, N, P, and O elements (Figure S7,
AN400/800 in Figure 3C discloses a unique fluffy coral-like structure ESI). The peaks in the range of 224-240 eV can be assigned to 3d5/2
(Figure 3B), indicating the reconstruction of catalyst composition and 3d3/2 of Mo (Figure 5A). The high-resolution Mo 3d spectrum
and framework. The EDS elemental mapping images of PMo@DIM- of PMo@DIM-AN400/800 reveals four oxidation states for Mo,
AN400/800 shows that P, Mo, N, C and O elements are uniformly corresponding to Mo2+ (228.4 and 231.6 eV), Mo3+ (228.9 and 232.2
distributed in the sample (Figures S5 and S6, ESI). Unlike eV), Mo4+ (233.1 and 235.8 eV), and Mo6+ (233.4 and 236.2eV)
PMo@DIM-AN400/800, the TEM image of PMo@DIM-AN800 exhibits a species, respectively. Mo6+ and Mo4+ can be ascribed to
similar morphology to that of PMo@DIM-AN400, but angular molybdenum oxides (MoOx) possibly from the surface oxidation of
particles with a more smooth surface were observed (Figure 3C). Mo species during the pyrolysis treatment, as observed in previous
Additionally, the AN-free sample PMo@DIM400/800 shows a lamellar reports.[42-43] Mo3+ is related to molybdenum and nitrides, and Mo2+
structure which composed of small aggregated particles (Figure 3D). belongs to Mo2C, which are known to serve as active sites for
oxidation dehydrogenation of alcohols.[18,44] However, there are
only two oxidation states of Mo, that is, Mo4+ (233.0eV) and Mo6+
shell morphology that the stripy Mo2C is completely coated by the
The TEM images of PMo@DIM-AN400/800 show an obvious core-
(233.2 and 236.1eV) for PMo@DIM-AN800, and three oxidation
carbon shells (Figures 4A and 4D). The carbon shells are multiple
states of Mo3+ (228.9 and 232.2 eV), Mo4+ (233.1 and 235.8 eV), and
layers with the thickness of about 3 nm and a d-spacing of 0.3 nm
Mo6+ (233.4 and 236.2eV) are observed for PMo@DIM400/800. This
quality graphitic carbon.[41] The high power transmission (HTEM)
suggests that Mo species are more translated into molybdenum
(Figure 4E), corresponding to the typical layer spacing of high-
oxide and molybdenum nitride for PMo@DIM-AN800 and
reveals the well-defined crystals that are homogeneously
PMo@DIM400/800, rather than Mo2C.
distributed in the CN shell, the lattice plane distance is about 0.25
nm, which is consistent with the lattice plane of Mo2C (Figure 4F).
According to previous literatures, the characteristics of the N-
The TEM image of PMo@DIM-AN400 shows the homogeneous containing carbon groups are contributive for the formation of
contrast (Figure 4B), which is similar to that of PMo@DIM-AN transition metal carbides.[45] In the N 1s XPS spectra (Figure 5B),
(Figure S4B, ESI), indicating the homogeneous distribution of PMo PMo@DIM-AN400/800 exhibits four types of nitrogen environments,
in the composite. In the TEM image of PMo@DIM-AN800, there is no which can be attributed to pyridinic-N (398.4 eV), N-Mo (394.9 eV)
carbon shell was observed. Additionally, PMo@DIM-AN800 disclose a pyrrolic-N (399.0 eV), and graphitic-N (401.4 eV), respectively. The C
number of particles in the darker contrast (Figure 4C), suggesting 1s XPS spectrum confirms the formation of C-Mo, C-C, C=C, and C=N
that the PMo may be converted to metal oxides. The observations in PMo@DIM-AN400/800 (Figure 5C). Compared with PMo@DIM-
in TEM images are consistent well with the results of XRD and AN400/800, only a weak pyridinic N 1s peak was observed for
Raman analysis.
PMo@DIM-AN800. This can be attributed to the release of nitrile
species during the direct pyrolysis treatment at 800 °C. Although
PMo@DIM400/800 reveals the existence of pyridinic N (398.9 eV),
X-ray photoelectron spectroscopy (XPS) spectra are measured to
confirm the chemical composition and valence states of PMo@DIM-
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pyrrolic N (399.8 eV) and graphitic N (401.5 eV), it is still difficult to nitride matrix through crosslinked polymerization and
generate Mo2C due the absence of sufficient carbon source as carbonization, which may prevent the further elimination of
demonstrated by the low intensity of C 1s XPS peaks. The results of nitrogen and carbon and effectively convert the Mo species into
above characterization analysis indicate that the pretreatment of Mo2C through carbothermal reduction at 800 °C.
PMo@DIM-AN at 400 °C firstly carbonization of DIM-AN to carbon
Mo 3d
N 1s
(A)
C 1s
C-N/C=N
(C)
(a)
(B)
C-C/C=C
pyrrolic-N
(399.0 eV)
Mo2C
(285.1 eV)
C-Mo
(284.5 eV)
pyridinic-N
(398.4 eV)
N-Mo
graphitic-N
(285.7 eV)
(a)
(b)
(394.9 eV)
(401.4 eV)
(a)
(b)
(c)
Mo2+
MoO2
Mo3+
Mo4+
Mo6+
MoO3
(b)
(c)
MoN
(c)
225
230
235
240
390
395
400
405
280
285
290
Binding Energy (eV)
Binding Energy (eV)
Binding Energy (eV)
Figure 5. (A) Mo 3d spectra, (B) N 1s spectra, and (C) C 1s spectra of (a) PMo@DIM-AN400/800, (b) PMo@DIM-AN800, and (c) PMo@DIM400/800
.
close to those of PMo@DIM-AN and MoO3, but they are significant
lower than that of PMo@DIM-AN400/800. The low efficiency of these
control catalysts can be relative to their compositions based on
Raman analysis, XRD, and XPS, which revealed that PMo@DIM-
Catalytic tests for oxidant-free dehydrogenation of benzyl
alcohol
The catalytic properties of the as-prepared catalysts were tested
in the oxidant-free dehydrogenation of benzyl alcohol to
benzaldehyde in DMSO at 120 °C, and the results are summarized in
Table 1. MoO3 was proved to be active and soluble in the reaction
media and shows a moderate yield of 62.8% and selectivity of 100%
(entry 1). The hybrid PMo@DIM-AN also causes a homogeneous
reaction system but exhibits lower activity than that of MoO3, giving
3-
AN400 is composed of Keggin type PMo12O40 anions, PMo@DIM-
AN800 and PMo@DIM400/800 are composed of molybdenum oxides.
Based on these comparison results, the extremely high activity of
PMo@DIM-AN400/800 should rely on the active Mo2C phase, which
favors the effective and selective dehydrogenation of alcohols.
a 33.6% yield (entry 2). To our delight, the catalyst PMo@DIM- Table
1
Catalytic performances of various catalysts for
AN400/800 demonstrates superior activity, showing 100% yield with dehydrogenation of benzyl alcohol. a
100% selectivity (entry 3, GC spectrum in Figure S8 in ESI). The
Catalyst
O
OH
results of reaction condition optimization, including reaction
temperature, reaction time, catalyst amount, and solvent used are
shown in Figure S9 and Table S1 in ESI. It should be noted that the
reactions were carried out with the nitrogen ball protection, and
the catalyst boosts only the dehydrogenation of benzyl alcohol,
rather than oxidation with oxidant. So, the high selectivity of 100%
obtained can be understandable. Furthermore, PMo@DIM-AN400/800
was completely insoluble in the reaction media and led to a
heterogeneous catalytic system. Therefore, after reaction,
PMo@DIM-AN400/800 can be facilely separated by filtration and
reused. The five-run recycling assessment reveals a quite steady
reusability without observing significant loss of yields and selectivity
(Figure S10(A), ESI). In addition, the SEM and TEM images of the
PMo@DIM-AN400/800 recycled from oxidation dehydrogenation
system are similar to that of the fresh one (Figure S10(C and D),
ESI), and the XRD patterns (Figure S10(B), ESI) confirms that the
recovered PMo@DIM-AN400/800 retain its original crystalline
structures, suggesting the outstanding durability of this catalyst.
+
H2
120 ℃
DMSO
Solubility in
reaction
Yield b
(%)
Sel c
(%)
Entry
Catalyst
1
2
3
4
5
6
7
8
9
MoO3
PMo@DIM-AN
Homogenous
Homogenous
62.6
33.6
100
58.2
46.9
62.5
30.8
12.7
-
100
100
100
100
100
100
100
100
-
PMo@DIM-AN400/800 Heterogeneous
PMo@DIM-AN400
PMo@DIM-AN800
PMo@DIM400/800
DIM-AN400/800
DIM-AN800
Heterogeneous
Heterogeneous
Heterogeneous
Heterogeneous
Heterogeneous
Heterogeneous
Active carbon
a Reaction conditions: benzyl alcohol (2 mmol), dimethyl sulfoxide (4
b
The control catalysts PMo@DIM-AN400, PMo@DIM-AN800, and
PMo@DIM400/800 also behaved as heterogeneous catalysts. They
present 46-63% yields with 100% selectivity (entries 4-6), which are
mL), catalyst (0.05 g), 120 °C, 4 h.
determined by GC, c Selectivity for the benzaldehyde product.
Yield of the substrate
6 | J. Name., 2012, 00, 1-3
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It is well known that the properties of a catalyst support, such as are responsible for the excellent catalytic performance.
electronic property and acid-base property, play important roles in
It has been reported that the basic sites of the catalsyt can
alcohol dehydrogenation.[46] We thus speculate that the excellent
exhibit nucleophilic activity and abstraction of proton from alcohol
performance of PMo@DIM-AN400/800 might be associated with the
to improve the catalytic performance of dehydrogenation
reaction.[47] Additionally, the existence of N species can improve the
surface N-doped carbon shell. Subsequently, the control PMo-free
electric property and increase the basic sties of carbon materials.[48]
samples DIM-AN400/800 and DIM-AN800 were prepared and tested as
the catalysts for oxidant-free dehydrogenation of benzyl alcohol.
Therefore, N-doped carbon shell on PMo@DIM-AN400/800 may acts
The results are listed in Table 1. Interestingly, DIM-AN400/800 gives
as basic sites and electron regulator for Mo2C, which favors proton
30.8% yield of benzaldehyde (entry 7), while DIM-AN800 offers
abstraction and transfer from the substrate alcohol under oxidant-
12.7% yield (entry 8). It is likely that the catalytic efficiency of DIM-
free conditions, and thus result in the enhanced catalytic activity.
AN400/800 and DIM-AN800 is primarily relative to the amount of N
Based on the characterization and comparison experimental results,
and also according to previous reports,[49-50] a possible mechanism
atoms in catalyst, the high content of N in DIM-AN400/800 tends to
give higher catalytic activity, as indicated by XPS results. The N-free
of synergistic effect involving the active Mo2C phase and basic N
acitive carbon is almost inactive for dehydrogenation of benzyl
sites is proposed for the dehydrogenation of alcohols into carbonyl
alcohol, which further confirms that the N atoms in the carbon shell
compounds. As illustrated in Scheme 2, the O-H bond of benzyl
Table 2. Catalytic dehydrogenation oxidation of various alcohols with air. a
Entry
Substrate
Product
Time (h)
Con b (%)
Sel b (%)
OH
O
1
4
100
100
Cl
Cl
Cl
Cl
2
OH
OH
6
100
100
O
CH3
CH3
3
4
4
6
100
100
100
100
O
O
O
OH
O
H3C
H3C
OH
5
8
100
100
CH3
CH3
OCH3
OCH3
6
7
8
9
OH
4
6
8
4
100
100
100
100
100
100
100
100
OH
O
H3CO
H3CO
Br
Br
OH
O
OH
O
I
I
OH
O
10
11
12
12
12
24
93.2
100
100
100
100
OH
O
S
S
OH
O
43.4
O
OH
13
24
51.2
100
14
15
-
-
-
OH
OH
O
O
12
9.6
100
a Reaction conditions: 2 mmol alcohol, 4 mL dimethyl sulfoxide, 120 °C, 0.05g PMo@DIM-AN400/800
c Selectivity for the oxide product.
.
b Conversion of the substrate,
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alcohol was first activated by the basic and electron-rich N site to the dehydrogenation of benzyl alcohol without the changing of its
form the negatively charged intermediate (alkoxide) and a proton. crystalline structure. The characterizations and control experiments
Then, the extraction of a hydrogen (cleavage of C–H bond) from the results demonstrate that the synergistic effects of active Mo2C sites
alkoxide occurred on the Mo site in Mo2C, yielding benzaldehyde and basic N atoms in the carbon shell are responsible for the
and a hydride species. This step is the rate-determining step. enhance catalytic performance. This work provides an efficient and
Finally, the hydride species on the Mo site react with proton on the feasible route to prepare N-doped carbon encapsulated Mo2C for
N site to generate dihydrogen that was released from the catalyst oxidant-free dehydrogenation of alcohols.
surface. The basic N sites in the carbon shell are mainly account for
proton abstraction from alcohol, while the active Mo2C promote
Acknowledgements
the cleavage of the C–H bond in alkoxide, and consequently the
catalyst PMo@DIM-AN400/800 showed higher activity.
The authors thank the National Natural Science Foundation of China
(No. 21206052), MOE & SAFEA for the 111 Project (No. B13025),
and the Fundamental Research Funds for the Central Universities
(JUSRP51623A).
Notes and references
1
2
3
P.F. Zhang, Y.T. Gong, H.R. Li, Z.R. Chen and Y. Wang, Nat.
commun., 2013, , 1593-1604.
Y. Leng, J. Wang, P.P. Jiang, Catal. Commun., 2012, 27, 101-
104.
W.J. Song, A.K. Vannucci, B.H. Farnum, A.M. Lapides, M. Kyle
Brennaman, B. Kalanyan, L.L. Alibabaei, J. J. Concepcion, M.
D. Losego, G. N. Parsons and T. J. Meyer, J. Am. Chem. Soc.,
2014, 136, 9773-9779.
W.H. Fang, Q.H. Zhang, J. Chen, W.P. Deng and Y. Wang,
Chem. Commun., 2010, 46, 1547-1549.
J.W. Zheng, J. Qu, H.Q. Lin, Q. Zhang, X. Yuan, Y.H. Yang and
4
Scheme 2. Proposed reaction mechanism for the oxidant-free
dehydrogenation of alcohol on PMo@DIM-AN400/800 catalyst.
To evaluate the scope of the reaction, we examined the
dehydrogenation of various alcohols using PMo@DIM-AN400/800 as
the catalyst without any additives under oxidant-free conditions. As
shown in Table 2, the type and location of substituent groups on
the aromatic ring have slight influences on the catalytic yields. Most
aromatic alcohols and furan-2-ylmethanol could be completely
converted to the corresponding aldehydes with excellent
selectivity. PMo@DIM-AN400/800 only exhibits moderate activity for
the dehydrogenation of phenethyl alcohol and cyclohexanol, giving
43.4% and 51.2% yield, respectively. In the case of the linear
alcohols, n-butyl alcohol and 2-octanol, low yields of less than 10%
are obtained. Notably, the dehydrogenation of linear alcohol is
rather difficult reaction that could not produce high yields as well
over other catalysts even in the presence of oxidant,[51] which is
probably due to the large value of C-H force constant k. In general,
4
5
6
7
8
9
Y.Z. Yuan, ACS Catal., 2016,
D. Ventura-Espinosa, C. Vicent, M. Bayac and J.A. Mata,
Catal. Sci. Technol., 2016, , 8024-8035.
6, 6662-6669.
6
H.J. Xie, Y. Li, L.T. Huang, F.L. Nong, G.R. Ren, T. Fan, Q.F. Lei
and W.J. Fang, Dalton Trans., 2016, 45, 16485-16491.
W. Fu, L.M. Yue, X.G. Duan, J. Li and G.Z. Lu, Green Chem.,
2016, 18, 6136-6142.
R.K. Marella, C.K. Prasad Neeli, S.R. Rao Kamaraju and D.R.
Burri, Catal. Sci. Technol., 2012,
10 H. Chen, S. He, M. Xu, M. Wei, D.G. Evans and X. Duan, ACS
Catal., 2017, , 2735-2743.
11 Y. Lu, H.X. Ang, Q.Y. Yan and E. Fong, Chem. Mater., 2016,
28, 5743-5752.
2, 1833-1838.
7
the catalytic ability of PMo@DIM-AN400/800 for dehydrogenation of 12 Z.H. Pu, M. Wang, Z.K. Kou, I.S. Amiinu and S.C. Mu, Chem.
Commun., 2016, 52, 12753-12756.
alcohols with high efficiency under oxidant and additive-free
13 X. Li, L. Yang, T. Su, X.L. Wang, C.Y. Sun and Z.M. Su, J. Mater.
Chem. A, 2017, 5, 5000-5006.
14 Y.P. Liu, G.T. Yu, G.D. Li, Y.H. Sun, T. Asefa, W. Chen and X.X.
Zou, Angew. Chem., 2015, 127, 10902-10907.
15 E.T. Liakakouab and E. Heracleous, Catal. Sci. Technol., 2016,
conditions is advantageous to some existing precious metal-based
homogeneous and heterogeneous catalysts.[52-53] The catalytic
performance of PMo@DIM-AN400/800 was also comparable with
other metallic oxides and carbides catalysts, which require long
reaction time to achieve high efficiency.[54-55]
6
, 1106-1119.
16 E. Puello-Polo, M. Ayala-G, J.L. Brito, Catal. Commun., 2014,
53, 9-14.
17 W.Q. Zheng, T.P. Cotter, P. Kaghazchi, T. Jacob, B. Frank, K.
Schlichte, W. Zhang, D.S. Su, F. Schüth and R. Schlögl, J. Am.
Chem. Soc., 2013, 135, 3458-3464.
18 Z.C. Li, C.H. Chen, E.S. Zhan, N. Ta, Y. Li and W.J. Shen, Chem.
Commun., 2014, 50, 4469-4477.
19 H.B. Wu, B.Y. Xia, L. Yu, X.Y. Yu and X.W. (David) Lou, Nat.
commun., 2015, 6, 6512-6520.
20 C. Wan, Y. N. Regmi and B. M. Leonard, Angew. Chem., 2014,
126, 6525-6528.
Conclusions
In summary, we have demonstrated a new example of N-doped
carbon encapsulated molybdenum carbide (PMo@DIM-AN400/800),
which is prepared through
a simple anion exchange and
carbothermal route. The morphology, composition and structure of
the produced samples are highly dependent on the ionic group
composition and pyrolysis strategy. The catalyst PMo@DIM-
AN400/800 exhibits outstanding catalytic activity and selectivity for
dehydrogenation of various alcohols under oxidant-free conditions.
In addition, the catalyst can be steadily reused at least five times for
21 B. Zhang, H. Asakura, J. Zhang, J.G. Zhang, S. De and N. Yan,
Angew. Chem. Int. Ed., 2016, 55, 8319-8323.
22 B. Zhang, H. Asakura and N. Yan, Ind. Eng. Chem. Res.,2017,
56, 3578-3587.
8 | J. Name., 2012, 00, 1-3
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23 X.J. Yang, X.J. Feng, H.Q. Tan, H.Y. Zang, X.L. Wang, Y.H. 39 L. Liao, S.N. Wang, J.J. Xiao, X.J. Bian, Y.H. Zhang, M.D.
Scanlon, X.L. Hu, Y. Tang, B.H. Liu and H.H. Girault, Energy
Environ. Sci., 2014, ,387-392.
Wang, E. Wang and Y.G. Li, J. Mater. Chem. A, 2016,
3954.
4, 3947-
7
24 J.S. Li, Y.J. Tang, C.H. Liu, S.L. Li, R.H. Li, L.Z. Dong, Z.H. Dai, 40 L.L. Huo, B.C. Liu, G. Zhang and J. Zhang, ACS Appl. Mater.
J.C. Bao and Y.Q. Lan, J. Mater. Chem. A, 2016, , 1202-1207. Interfaces, 2016, , 18107-18118.
25 C.H. Liu, Y.J. Tang, X.L. Wang, W. Huang, S.L. Li, L.Z. Dong and 41 X.J. Fan, Y.Y. Liu, Z.W. Peng, Z.H. Zhang, H.Q. Zhou, X.M.
4
8
Y.Q. Lan, J. Mater. Chem. A, 2016,
26 J.S. Li, Y. Wang, C.H. Liu, S.L. Li, Y.G. Wang, L.Z. Dong, Z.H.
4
, 18100-18106.
Zhang, B.I. Yakobson, W.A. Goddard III, X. Guo, R.H. Hauge
and J.M. Tour, ACS Nano, 2017, 11, 384-394.
Dai, Y.F. Li and Y.Q. Lan, Nat. commun., 2016, 7, 11204- 42 C.Y. Tang, W. Wang, A. Sun, C.K. Qi, D.Z. Zhang, Z.Z. Wu and
11212. D.Z. Wang, ACS Catal., 2015, , 6956-6963.
27 Y.Y. Ma, C.X. Wu, X.J. Feng, H.Q. Tan, L.K. Yan, Y. Liu, Z.H. 43 Y. Huang, Q.F. Gong, X.N. Song, K. Feng, K.Q. Nie, F.P. Zhao,
5
Kang, E. Wang and Y.G. Li, Energy Environ. Sci., 2017, 10
788-798.
,
Y.Y. Wang, M. Zeng, J. Zhong and Y.G. Li, ACS Nano, 2016, 10,
11337-11343.
28 Y.Y. Chen, Y. Zhang, W.J Jiang, X. Zhang, Z.H. Dai, L.J. Wan 44 Z.C. Li, C.H. Chen, E.S. Zhan, N. Ta, W.J. Shen, Catal.
and J.S. Hu, ACS Nano, 2016, 10, 8851-8860. Commun., 2014, 51, 58-62.
29 X.C. Cai, Q. Wang, Y.Q. Liu, J.Y. Xie, Z.Y. Long, Y. Zhou and J. 45 G. Yan, C.X. Wu, H.Q. Tan, X.J. Feng, L.K. Yan, H.Y. Zang and
Wang, ACS Sustain. Chem. Eng., 2016, , 4986-4996. Y.G. Li, J. Mater. Chem. A, 2017, , 765-772.
30 Y. Leng, J. Liu, P.P. Jiang and J. Wang, ACS Sustain. Chem. 46 Q.H. Zhang, W.P. Deng and Y. Wang, Chem. Commun., 2011,
Eng., 2015, , 170-176. 47, 9275-9292.
31 Y. Leng, J.W. Zhao, P.P. Jiang, D. Lu, Catal. Sci. Technol., 2016, 47 X.W. Wang, C. Wang, Y.X. Liu and J.L. Xiao, Green Chem.,
, 875-881. 2016, 18, 4605-4610.
32 Y. Leng, J.W. Zhao, P.P. Jiang and J. Wang, ACS Appl. Mater. 48 Y.M. Lin and D.S. Su, ACS Nano, 2014, 8, 7823-7833.
4
5
3
6
Interfaces, 2014,
6
, 5947-5954.
49 K. Shimizu, K. Sugino, K. Sawabe and A. Satsuma, Chem. Eur.
J. 2009, 15, 2341-2351.
50 R.K. Shi, F. Wang, Y. Li, X.M. Huang and W.J. Shen, Green
Chem., 2010, 12, 108-113.
51 Y. Leng, J. Liu, P.P. Jiang and J. Wang, RSC Adv., 2012, 2,
11653-11656.
52 M. Wang, F. Wang, J.P. Ma, M.R. Li, Z. Zhang, Y.H. Wang, X.C.
Zhang and J. Xu, Chem. Commun., 2014, 50, 292-294.
33 Y. Leng, J. Wang, D.R. Zhu, X.Q. Ren, H.Q. Ge and L. Shen,
Angew. Chem., 2009, 121, 174-177.
34 B. Qiu, C.T. Pan, W.J. Qian, Y.J. Peng, L.H. Qiu and F. Yan, J.
Mater. Chem. A, 2013,
35 K. Gupta, T.Y. Liu, R. Kavian, H.G. Chae, G.H. Ryu, Z. Lee, S.W.
Lee and S. Kumar, J. Mater. Chem. A, 2016, , 18294-18299.
36 M.J. Zhong, E.K. Kim, J.P. McGann, S.F. Chun, J.F. Whitacre,
1, 6373-6378.
4
M. Jaronie, K. Matyjaszewski and T. Kowalewski, J. Am. 53 K. Kon, W. Onodera, T. Toyao and K.I. Shimizu, Catal. Sci.
Chem. Soc., 2012, 134, 14846-14857. Technol., 2016, , 5864-5870.
37 Z.W. Seh, K.D. Fredrickson, B. Anasori, J. Kibsgaard, A.L. 54 H.S. Song, B. Kang and S.H. Hong, ACS Catal., 2014,
Strickler, M.R. Lukatskaya, Y. Gogotsi, T.F. Jaramillo and A. 2895.
Vojvodic, ACS Energy Lett., 2016, , 589-594.
6
4, 2889-
1
55 J. Yi, J.T. Miller, D.Y. Zemlyanov, R.H. Zhang, P.J. Dietrich, F.H.
Ribeiro, S. Suslov and M.M. Abu-Omar, Angew. Chem. 2014,
126, 852-855.
38 P. Xiao, Y. Yan, X.M. Ge, Z.L. Liu, J.Y. Wang, X. Wang, Appl.
Catal., B, 2014, 154-155, 232-237.
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