N-Doped Hierarchical Porous Carbon Embedded Synergistic Bimetallic CoCu NPs with Unparalleled Catalytic Performance

Article abstract of DOI:10.1002/cctc.201900283

By virtue of the structural diversity, electronic tunability and synergetic effect, heterogeneous non-noble bimetallic catalysts have demonstrated excellent catalytic performance in Fischer-Tropsch synthesis, biomass conversion and fine chemicals synthesi

Full text of DOI:10.1002/cctc.201900283

DOI: 10.1002/cctc.201900283
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N-Doped Hierarchical Porous Carbon Embedded Synergistic
Bimetallic CoCu NPs with Unparalleled Catalytic
Performance
+
[a]
+ [a, b]
[a, b]
[a, b]
[a]
Fengwei Zhang ,* Zhihong Li ,
Zhengping Dong,* and Xian-Ming Zhang*
Chunlan Ma,
Xu Han,
Xue Dong,
[c]
[a]
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[
1]
By virtue of the structural diversity, electronic tunability and
synergetic effect, heterogeneous non-noble bimetallic catalysts
have demonstrated excellent catalytic performance in Fischer-
Tropsch synthesis, biomass conversion and fine chemicals
synthesis community. However, the feature of synergetic effect
and formation mechanism of bimetallic CoCu NPs under
carbothermal conditions still remain to be explored. Herein we
report an efficient protocol for fabrication of a representative N-
doped hierarchical porous carbon embedding bimetallic CoCu
NPs catalyst. Particularly, the prepared Co Cu @NHPC-800
due to their abundance and easy availability. Although a set
number of preliminary studies have been reported, non-noble
metal catalysts always suffer from sintering, oxidation and
leaching problems under relatively harsh conditions. Since
Beller’s group first reported the highly selective hydrogenation
[2]
of nitroaromatics by Fe-Phen/C-800 catalysts, a variety of
nitrogen and single non-noble metal components co-doped
carbon-based catalytic materials have attracted growing atten-
tion owing to their enhanced catalytic activity and excellent
stability originating from anchoring effect of doped N. Current
researches have undoubtedly demonstrated that combination
of non-noble metals and N-doped carbon based catalysts
possess superior catalytic performance in the selective reduc-
tion of nitroaromatics, N-heteroarenes, biomass derivatives and
[3]
0
.7
0.3
catalyst demonstrates unprecedented catalytic activity and
chemoselectivity for various nitroaromatics under extremely
mild condition (1 atm H , 30°C), which is superior to the
2
existing non-noble metal-based catalytic systems. It also
exhibits excellent activity for hydrolysis of ammonia borane in
pure water at room temperature. Furthermore, the possible
formation process of bimetallic NPs is firstly brought to light,
which could be the key to the nature of CoCu synergistic effect
as well as the resultant high activity and selectivity.
[4]
other unsaturated alicyclic/aromatic systems. And different
types of reductants (NaBH , NH ·BH , N ·H O, HCOOH, and H
have been successively applied in the catalytic reduction of the
H
2
)
2
4
3
3
4
2
[5]
aforementioned substrates.
Among these reductants, only H
is an economical, well-
2
sourced, pollution-free hydrogenation reagent and even with
complete atomic efficiency. However, the activation of H2
suffers from formidable challenges for non-noble metal cata-
lysts, which lie primarily in rather harsh conditions such as high
The catalytic reduction of nitroaromatics to important aniline
intermediates is a piece of cake for noble metal-based catalysts,
yet the reaction process is often confronted with high price,
limited availability, complicated structure regulation of active
components, carbon-halogen (CÀ X) bond hydrogenolysis of
substrates as well as other intractable problems. To address
these issues, researchers have focused their efforts on more
earth-abundant alternatives, especially Fe, Co and Ni metals
[
6]
temperature and high pressure (>100°C, 5.0 MPa H ). From
2
an academic and industrial perspective, a sufficiently low
activation temperature and pressure of H is generally needed
2
so that large energy consumption and harsh requirements of
reaction device could be ameliorated. Fortunately, heteroge-
neous CoN À C catalysts were found to be the ideal candidate
x
for hydrogenation related reactions among MN À C materials, as
x
the reduced cobalt could promote the cleavage of H-H bonds
and achieve the quantitative hydrogenation for nitroaromatics
+
+
[7]
[
a] F. Zhang, Z. Li, C. Ma, X. Han, X. Dong, X.-M. Zhang
Institute of crystalline materials
Shanxi University
under mild conditions. More importantly, selective hydro-
genation of -NO groups can be performed in the presence of
2
Taiyuan 030006 (P.R. China)
E-mail: fwzhang@sxu.edu.cn
xmzhang@sxu.edu.cn
b] Z. Li, C. Ma, X. Han
Institute of Molecular Science
Shanxi University
Taiyuan 030006 (P.R. China)
c] Prof. Z. Dong
School of Chemistry and Chemical Engineering
Lanzhou University
Lanzhou 730000 (P.R. China)
E-mail: dongzhp@lzu.edu.cn
groups such as halogens, olefins, alkynes and carbonyls for
cobalt-based catalysts, which addresses the drawback of fine-
tuned Pd and Pt catalysts and brings about great convenience
+
[
[
[8]
for production of fine chemicals.
Other prominent challenges for metal catalysts include the
limited regulation technique of metal’s doping amount, contact
area as well as electronic interaction ability, which hamper
further improvements in the catalytic performance and chemo-
selectivity. Considering the formation of bimetallic nanopar-
ticles (NPs) can greatly tune the activity and selectivity of
+
[
] These authors contributed equally.
[9]
catalysts, we believe it would be a promising strategy to
incorporate two metal components into the N-doped carbon
Supporting information for this article is available on the WWW under
https://doi.org/10.1002/cctc.201900283
ChemCatChem 2019, 11, 1–9
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Scheme 1. Schematic illustration of the synthesis of CoCu@NHPC-T catalyst.
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matrix to further enhance their catalytic capacity. It is worth
noticing that some bimetallic CoCu NPs catalysts have been
diameter distribution ranging from ~12 nm to ~62 nm and are
well-dispersed inside the N-doped porous carbon frameworks.
To our surprise, an extraordinary phenomenon is brought to
light that the average size of Co Cu @NHPC-800 (27 nm)
catalyst is less than Co Cu @NHPC-700 (38 nm), indicating
0.7 0.3
there is a splitting and reconstruction process of Cu NPs
deriving from reduction of Co species (Figure S1). We infer that
[10]
successfully applied in Fischer-Tropsch synthesis, hydrogena-
[
11]
[12]
tion of biomass-derived substances,
conversion,
electrocatalysis, CO
2
0.7
0.3
[13]
[14]
as well as hydrolysis of ammonia borane.
Yasukawa et al. prepared N-doped carbon-supported Co/Cu
[15]
bimetallic NPs catalysts for aerobic oxidative of esterifications.
Feng et al. reported Cu Co O NPs anchored on graphene oxide
2
+
2+
Cu are firstly reduced to Cu NPs under 700°C, whereas Co
x
1-x
as a synergistic catalyst for efficient hydrolysis of ammonia
are further reduced to Co NPs and simultaneously inserted into
Cu NPs under 800°C, thus generating the well-dispersed and
relatively smaller CoCu NPs. Similar process was reported that
Cu NPs breaks up into small nanoclusters in the presence of CO
[16]
borane.
However, these catalysts are usually prepared by
deposition-reduction technique, thus easily suffer from poor
stability and weak interaction between metals.
[17]
From the above considerations, we attempt to design a
highly efficient and stable heterogeneous bimetallic CoCu NPs
catalyst through in-situ incorporating two non-noble metals
into the N-doped porous carbon framework, which resultantly
further reduces the activation energy barrier of nitroaromatics
hydrogenation, enabling it operated under extremely mild
conditions. In general, by self-assembling of two metal
phthalocyanine precursors with the commercially available
colloidal silica HS-40 followed by thermolysis and etching
combined strategy, the bimetallic nanocatalysts were easily
accessible. The performance of the as-prepared catalysts were
further optimized by adjusting the mass ratio of both metal
sources and pyrolysis temperature. The CoCu mass ratio of 7:3
was found to be optimal when calcining the precursor at 800°C
for 2 h. Kinetic experiments prove the apparent activation
energy of nitrobenzene hydrogenation is as low as 26.2 kJ/mol,
which is the minimum value among the reported non-noble
metal based catalysts. Moreover, the Co Cu @NHPC-800
gas or co-doped CuRu species.
Indeed, the inserted Co
constituent could not only redisperse Cu NPs but also prevent
the aggregation and agglomeration. To verify our hypothesis,
the control sample Cu@NHPC-800 was synthesized (Figure S2),
resulting in larger Cu NPs as expected (>40 nm), which
confirms the essential and unique role of the incorporated
cobalt component. High-angle annular dark field scanning
transmission electron microscopy (HAADF-STEM) and EDS
mapping images of Co Cu @NHPC-800 further confirm that
0
.7
0.3
the C and N elements are homogeneously distributed in the
porous carbon framework, while the Co and Cu components
are well-surrounded by a plentiful of C and N atoms. Addition-
ally, TEM linear scan result shows that the nanocrystal consists
of uniformly distributed bimetallic CoCu NPs, which is
surrounded by abundant nitrogen species (Figure S3).
In Figure 2a, the XRD patterns of Co@NMC-800 and
Cu@NHPC-800 reveal that both Co and Cu species exist in the
form of metallic state, respectively. For prepared Co Cu @NHPC-
0
.7
0.3
x
y
catalyst also exhibits an impressive activity for hydrolysis of
ammonia borane (AB) under mild condition, which demon-
strates its potential application in convenient hydrogen storage
and release.
800 catalyst, no diffraction peak of CoOx and CuOx can be
detected, signifying that all of the CoCu constituents are
presented in metallic state in the bulk phase owing to the high
temperature reduction characteristic of the support. N sorption
2
In the present work, the Co, Cu-bimetallic embedded N-
doped hierarchical porous carbon was prepared through
thermal annealing of the physically assembled CoPcÀ CuPc and
measurements were carried out to investigate the surface area
and pore size distribution of the as-prepared catalysts (Fig-
ure 2c, 2d and Figure S4). The results indicate that all of
catalytic materials exhibit type-I and type-IV isotherms with
silica under flowing N atmosphere, followed by removal of the
2
SiO2 template in NaOH aqueous solution (as shown in
scheme 1). By adjusting CoCu mass ratio and pyrolysis temper-
ature, a series of Co Cu @NHPC-T catalysts were successfully
sharp uptakes at a relatively low N pressure (<0.1) and well-
2
defined hysteresis loops at higher N pressure (from 0.6 to 1.0),
2
illustrating the co-existence of micropores and mesopores. The
surface area and pore volume of the as-prepared samples are
x
y
obtained (where x=0~1, y=1~0, NHPC refers to nitrogen-
doped hierarchical porous carbon, T=700-1000°C).
2
À 1
3
À 1
ranging from 381 to 1848 m g and 0.97 to 3.51 cm g ,
suggesting the highly porous structure and more exposed
active sites. Notably, our previous work has proved that the
TEM images of Co Cu @NHPC-T (T=700–1000°C) in Fig-
0
.7
0.3
ure 1 show that the bimetallic CoCu NPs have a uniform
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Figure 1. The TEM and magnified TEM images of (a, e) Co0.7Cu0.3@NHPC-700, (b, f) Co0.7Cu0.3@NHPC-800, (c, g) Co0.7Cu0.3@NHPC-900 and (d, h) Co0.7Cu0.3@NHPC-
1
000 catalyst.
2 x y
Figure 2. (a) XRD patterns, (b) XPS survey scan, (c) N adsorption-desorption isotherms and (d) pore size distribution curves of Co Cu @NMC-T catalysts.
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Figure 3. (a) The Co2p spectra, (b) Cu2p spectra of Co0.7Cu0.3@NHPC-T catalyst (T=700–1000°C), (c) high-resolution XPS analysis in Co2p region and (d) high-
resolution XPS analysis in Cu2p region of Co0.7Cu0.3@NHPC-800 catalyst.
Co@NMC-800 catalyst without Cu doped only gives mesopo-
rous structure, while Cu-doped composites display typical
hierarchical porous structure, which could be helpful for
enhanced enrichment, migration and diffusion of substrates
and products in entire catalytic process.
energy has a slight shift to higher values compared with Cu/C
(932.5 eV and 952.5 eV), revealing possible electron transfer
[19]
from Cu to Co to equilibrate the Fermi level. The binding
energy at 780.2 eV, 783 eV and 787 eV could be ascribed to
[20]
Co O , CoO and the satellite peak of CoO, while the typical
3
4
XPS survey spectra display the C, N and O peaks in various
catalysts except for Co Cu @NHPC-1000, while the Co and Cu
peak at 778.2 eV of metallic Co (0) existing in Co@NMC-800 is
[21]
absent for Co Cu @NHPC-800. The result can be ascribed to
0
.7
0.3
0.7
0.3
signals are barely visible owing to the shielding effect of N-
doped graphitic carbon, which demonstrates that the majority
of CoCu NPs are anchored and embedded in the porous N-
doped carbon matrix (Figure 2b). In sharp contrast, the Co and
Cu contents in Co Cu @NHPC-800 determined by ICP-MS are
the surface oxidation of metallic Co during exposure in the air.
The XPS results display that the metallic Co on the surface of
Co Cu @NHPC-800 is relatively more active than on Co@NMC-
800. The high activity of Co might be attributed to the electron-
transfer interaction from Cu to Co species in N-doped carbon
framework.
0
.7
0.3
0.7
0.3
7
.77% and 2.96%, respectively (Table S6). The significant
decrease of N element in Co Cu @NHPC-1000 can be ascribed
The selective hydrogenation of various nitrobenzene deriv-
atives was carried out to evaluate the catalytic performance of
bimetallic CoCu catalysts. Among those catalysts with different
CoCu mass ratio, Co Cu @NHPC-800 showed optimal catalytic
0
.7
0.3
to the high temperature escape and etching effect of Cu
component. Additionally, the N content of Cu@NHPC-800 and
Co Cu @NHPC-800 is evidently lower than Co@NMC-800
0.7
0.3
0.7
0.3
(
Table S2), further proving the possible etching effect of Cu
activity for the benchmark reaction of nitrobenzene hydro-
genation, surpassing other Co Cu @NHPC-800 catalysts
species, which could be the origination of hierarchical porosity.
The high-resolution Co2p and Cu2p spectra are deconvoluted
to confirm the surface chemical state of the as-prepared
Co Cu @NHPC-800 catalyst (Figure 3). The binding energy
at 932.9 eV and 952.7 eV are ascribed to Cu2p3/2 and Cu2p1/2 of
Cu (0), respectively. It should be noticed that the binding
x
y
(Co Cu , Co Cu , Co Cu
and Co Cu ) as well as
0.9 0.1
0
.1
0.9
0.3
0.7
0.5
0.5
Co@NMC-800 (Table S4). However, Cu@NHPC-800 displayed
almost no catalytic activity. Admittedly, solvent effect plays a
critical role in the heterogeneous catalytic hydrogenation
[18]
0.7
0.3
[22]
reactions. Accordingly, different solvents are screened using
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[
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Table 1. Chemoselective hydrogenation of various substituted nitroaromatics by Co0.7Cu0.3@NHPC-800 catalyst.
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[
b]
[b]
Entry
Substrate
Product
t [h]
Conv. [%]
>99
Sel. [%]
>99
>99
>99
92
1
2
3
4
5
6
5
5
>99
6
>99
6
>99
1
1
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1
1
1
1
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>99
>99
>99
6
>99
7
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5
>99
>99
>99
>99
>99
97.1
>99
99
6
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0
1
>99
>99
7
1
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99
>99
1
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>99
>99
99
>99
>99
>99
15
1
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>99
>99
>99
>99
17
6.5
[
a] Reaction conditions: 1 mmol of nitroaromatics, 5 mL of MeOH, 50 mg of Co0.7Cu0.3@NHPC-800 catalyst (6.0 mol%), 1 atm of H
Selectivity were analyzed by GC, and n-tetradecane was used as internal standard, Conversion=[consumed substrate]/[initial substrate]×100, Selectivity=
product]/[product+other by-product]×100, respectively.
2
. [b] Conversion and
[
Co Cu @NHPC-800 as catalyst (Table S3). The result indicates
isolated yield for nitrobenzene, p-nitroanisole and p-chloroni-
trobenzene (Table S6). It should be noticed that monometallic
Cu@NHPC-800 shows no catalytic activity, although the doped
copper plays an indispensable role in CoCu composite indeed.
And a series of Co, Cu-based N-doped porous carbon catalysts
are tested in the selective hydrogenation of nitrobenzene under
the optimized conditions, determining that the optimal mass
ratio for CoPc/CuPc is 7:3 (Table S4). The enhanced catalytic
activity of Co Cu @NHPC-800 could be ascribed to the
synergistic effect of uniform CoCu bimetallic NPs, the high
surface area as well as the hierarchical porous structure.
Synergistic effect between Co and Cu species might facilitate H2
dissociation on the surface of nanoparticles. Moreover, it has
0.7
0.3
that MeOH is the optimum reaction solvent and the corre-
sponding nitrobenzene conversion could reach up to 86% with
>
99% aniline selectivity at 0.1 MPa of H , 80°C and 4 h (Table
2
S5).
As summarized in Table 1, Co Cu @NHPC-800 could also
0
.7
0.3
transform various nitroaromatics into corresponding substituted
anilines under extremely mild condition (1 atm H , 80°C and 6.0
2
mol% catalyst) quantitatively and efficiently, exhibiting much
higher catalytic activity than our reported Co@NMC-800 while
keeping the excellent chemoselectivity of monometallic cobalt
catalyst towards halonitrobenzenes and nitroaromatics with
reducible groups. Scaled-up reactions were also carried out
with 5-times amount of substrates, obtaining 94.1%–97.6%
0
.7
0.3
been reported that H spillover from dissociation sites on the
2
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Figure 4. (a) The plot of ln c (nitrobenzene) vs. reaction time under different temperatures, (b) Arrhenius plot of the rate constants over the reaction
temperature, (c) recyclability of nitrobenzene hydrogenation and (d) chemoselective hydrogenation of p-chloronitrobenzene.
Co NPs to the Cu (111) surface occurs via the CoÀ Cu interface,
800 catalyst, which is the lowest value in non-noble heteroge-
neous catalysts.
facilitating desorption of H occur at milder conditions as
[23]
compared with monometallic Co catalysts. Additionally, the
abundant hierarchical porous structure also helps the rapid
transport of substrates and products, providing sufficient active
a
b
g
¼ À d½NB�=dt ¼ k ½Cat� ½H � ½NB�
(1)
(2)
(3)
(4)
(5)
0
2
g
[24]
r ¼ À d½NB�=dt ¼ k ½NB�
sites as well, which results in enhanced catalytic activity.
Hot filtration test of Co Cu @NHPC-800 for nitrobenzene
0
0
.7
0.3
r ¼ À d½NB�=dt ¼ k0,
hydrogenation illustrated that there is no CoCu NPs escaping
from the support during the catalytic process and the reaction
follows heterogenous mechanism (Figure S6). The reaction
kinetics of Co Cu @NHPC-800 catalyst was conducted over
½NB� ¼ C À kt
0
0.7
0.3
ln k ¼ ln AÀ E =RT
a
the temperature range of 50-80°C in order to determine the
apparent activation energy (Ea) of nitrobenzene hydrogenation
(Figure 4a and 4b). The general rate formula of nitrobenzene
The recyclability of heterogeneous catalyst is of particular
importance in practical applications. The reusability of
Co Cu @NHPC-800 catalyst was assessed in the selective
hydrogenation is expressed by the following [Equation (1)]. The
formula can be further simplified to [Eq. (2)] because the
0
.7
0.3
catalyst amount is a constant and H has an extremely higher
hydrogenation of nitrobenzene and p-chloronitrobenzene. As
shown in Figure 4c and 4d, after the sixth recycled reaction,
such catalyst retained up to 96% and 98% of its original activity
under the identical conditions except the increased reaction
time, proving the good stability of our home-made catalyst for
nitroaromatics hydrogenation. In Figure S8, it can be seen that
the activity of Co Cu @NHPC-800 catalyst decreased after the
2
concentration compared to nitrobenzene (NB). Experiment
results demonstrate that the concentration of NB has a linear
relationship with reaction time t and the reaction process fits
well with pseudo-zero-order reaction mechanism, thus [Eq. (2)]
can be expressed as [Eq. (3) or (4)]. The extraction of the
apparent activation energy Ea from the Arrhenius equation
0.7
0.3
[
Eq. (5)] is determined to be 26.19 kJ/mol for Co Cu @NHPC-
fifth recycling (with 93% conversion after 6 h reaction time ).
0
.7
0.3
Then, the catalyst was calcinated under 500°C with flowing N
2
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Figure 5. The influence factors about hydrogen evolution of the hydrolysis of NH
different amount of Co0.7Cu0.3@NHPC-800 catalyst and (d) hydrolysis reaction temperature (Note: 1.6 mmol of NH
generated).
3
BH
3
(a) pyrolysis temperatures, (b) different metallic Co and Cu content, (c)
3 3 2
BH is used and finally 118 mL of H is
to reactivate it. TEM image of Co Cu @NHPC-800 after
could be ascribed to its high surface area (Table S1). The results
of different amount of catalysts prove that the adequate active
sites are indispensable for the rapid hydrogen release of AB
solution. As for hydrolysis temperature, the hydrogen gener-
ation rate is accelerated with the increase of reaction temper-
ature, indicating it is a thermodynamically favorable reaction.
There is no doubt that the excellent catalytic performance of
Co Cu @NHPC-800 at room temperature and pure water
0
.7
0.3
recycled 6 times showed no apparent agglomeration compared
with the fresh catalyst (Figure S7). ICP-MS results demonstrated
that the total weight loss of Co and Cu content was 10.81 wt%
(from 2.96% to 2.63% for Cu and 7.77% to 6.81% for Co),
confirming that the main reason for the decrease of such
catalyst in stability is the leaching of active species to some
extent.
0
.7
0.3
Furthermore, it has been reported that non-noble metal
catalysts exhibit excellent activity for hydrogen generation
application suggests the prosperous application prospect for
fast and controllable hydrogen release.
[25]
upon hydrolysis of AB.
The catalytic performance of
In summary, a facile in-situ thermolysis and etching
combined strategy is presented to synthesize a series of
uniformly dispersed bimetallic CoCu NPs embedded into N-
doped hierarchical porous carbon matrix. The obtained
Co Cu @NHPC-800 catalyst shows hierarchical porosity, high
surface area as well as synergetic effect, thereby providing
abundant exposed active sites and enhanced catalytic perform-
ance towards the hydrogenation of nitroaromatics and hydrol-
ysis of AB. TEM, physical adsorption, ICP-MS combined with XPS
characterizations reveal the dynamic formation process of CoCu
NPs structure under high temperature as well as the nature of
CoCu synergetic effect for in-depth explanation of superhigh
catalytic activity of Co Cu @NHPC-800 catalyst. Our method-
Co Cu @NHPC-T catalysts towards the hydrogen generation of
x
y
AB hydrolysis was also investigated by adjusting the pyrolysis
temperature, CoCu mass ratio, catalyst amount and reaction
temperature. As shown in Figure 5, different pyrolysis temper-
atures were investigated to verify the influence of CoCu NPs
size and nitrogen-containing content toward catalytic hydrolysis
of AB. As expected, the CoCu bimetallic catalyst prepared at
0
.7
0.3
8
00°C exhibits the highest catalytic activity. Moreover,
Co Cu @NHPC-800 displays the highest activity among the
five CoCu catalysts (Co Cu , Co Cu , Co Cu , Co Cu , and
0.7
0.3
0
.1
0.9
0.3
0.7
0.5
0.5
0.7
0.3
Co Cu ) as well as single Co and Cu catalyst, which is in good
0.9
0.1
agreement with the results of nitrobenzene hydrogenation. The
exception of relatively high activity of Co Cu @NHPC-800
0
.7
0.3
0
.1
0.9
ChemCatChem 2019, 11, 1–9
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7
© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Communications
ology could provide new insights for rational design of carbon-
based non-noble bimetallic catalysts.
Pei, Z. Qi, T. W. Goh, L.-L. Wang, R. V. Maligal-Ganesh, H. L. MacMurdo, S.
Zhang, C. Xiao, X. Li, F. Tao, D. D. Johnson, W. Huang, J. Catal. 2017, 356,
307–314; f) L. Liu, F. Gao, P. Concepción, A. Corma, J. Catal. 2017, 350,
1
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5
6
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0
1
2
3
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7
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9
0
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1
2
3
4
5
6
7
218–225; g) T.-N. Ye, Y. Lu, J. Li, T. Nakao, H. Yang, T. Tada, M. Kitano, H.
Hosono, J. Am. Chem. Soc. 2017, 139, 17089–17097; h) Y. Yang, G. Gao,
X. Zhang, F. Li, ACS Catal. 2014, 4, 1419–1425; i) G.-H. Wang, J. Hilgert,
F. H. Richter, F. Wang, H.-J. Bongard, B. Spliethoff, C. Weidenthaler, F.
Schüth, Nat. Mater. 2014, 13, 293–300.
Acknowledgements
This work is supported by Natural Science Foundation of China
[10] a) J. Su, Z. Zhang, D. Fu, D. Liu, X.-C. Xu, B. Shi, X. Wang, R. Si, Z. Jiang, J.
Xu, Y.-F. Han, J. Catal. 2016, 336, 94–106; b) Y. Xiang, R. Barbosa, N.
Kruse, ACS Catal. 2014, 4, 2792–2800; c) G. Prieto, S. Beijer, M. L. Smith,
M. He, Y. Au, Z. Wang, D. A. Bruce, K. P. de Jong, J. J. Spivey, P. E.
de Jongh, Angew. Chem. Int. Ed. 2014, 53, 6397–6401; Angew. Chem.
(21703129), Scientific and Technological Innovation Programs of
Higher Education Institutions in Shanxi (2017109) and Natural
Science Foundation for Young Scientists of Shanxi Province
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
2
014, 126, 6515–6519; d) K. Sun, X. Gao, Y. Bai, M. Tan, G. Yang, Y. Tan,
(2015021051). And we are also very grateful for the test platform
Catal. Sci. Technol. 2018, 8, 3936–3947.
provided by Shanxi University of Scientific Instrument Center.
[
11] a) J. Wu, G. Gao, P. Sun, X. Long, F. Li, ACS Catal. 2017, 7, 7890–7901;
b) Z. Huang, K. J. Barnett, J. P. Chada, Z. J. Brentzel, Z. Xu, J. A. Dumesic,
G. W. Huber, ACS Catal. 2017, 7, 8429–8440; c) Y. Wang, Y. Miao, S. Li, L.
Gao, G. Xiao, Mol. Catal. 2017, 436, 128–137; d) S. Srivastava, N. Solanki,
P. Mohanty, K. A. Shah, J. K. Parikh, A. K. Dalai, Catal. Lett. 2015, 145,
Conflict of Interest
8
16–823; e) W. Guo, H. Liu, S. Zhang, H. Han, H. Liu, T. Jiang, B. Han, T.
Wu, Green Chem. 2016, 18, 6222–6228; f) B. Chen, F. Li, Z. Huang, G.
The authors declare no conflict of interest.
Yuan, Appl. Catal. B: Environ. 2017, 200, 192–199.
[
[
12] Z. K. Ghouri, N. A. M. Barakat, H. Y. Kim, Sci. Rep. 2015, 5, 16695.
13] R. Nafria, A. Genç, M. Ibáñez, J. Arbiol, P. Ramírez de la Piscina, N. Homs,
A. Cabot, Langmuir 2016, 32, 2267–2276.
[14] a) Y. Ge, Z. H. Shah, X.-J. Lin, R. Lu, Z. Liao, S. Zhang, ACS Sustainable
Chem. Eng. 2017, 5, 1675–1684; b) Y. Liu, J. Zhang, H. Guan, Y. Zhao, J.-
H. Yang, B. Zhang, Appl. Surf. Sci. 2018, 427, 106–113; c) J. Li, Q.-L. Zhu,
Q. Xu, Catal. Sci. Technol. 2015, 5, 525–530; d) Q. Yao, Z.-H. Lu, Y. Wang,
X. Chen, G. Feng, J. Phys. Chem. C 2015, 119, 14167–14174.
[15] T. Yasukawa, X. Yang, S. Kobayashi, Org. Lett. 2018, 20, 5172–5176.
[16] K. Feng, J. Zhong, B. Zhao, H. Zhang, L. Xu, X. Sun, S.-T. Lee, Angew.
Chem. Int. Ed. 2016, 55, 11950–11954; Angew. Chem. 2016, 128, 12129–
12133.
[17] a) B. Eren, D. Torres, O. Karslıoğlu, Z. Liu, C. H. Wu, D. Stacchiola, H.
Bluhm, G. A. Somorjai, M. Salmeron, J. Am. Chem. Soc. 2018, 140, 6575–
Keywords: N-doped hierarchical porous carbon
·
CoCu
bimetallic catalyst · synergistic effect · selective hydrogenation ·
hydrolysis of ammonia borane
[
1] D. Formenti, F. Ferretti, F. K. Scharnagl, M. Beller, Chem. Rev. 2018, 119,
2
611–2680.
[2] R. V. Jagadeesh, A.-E. Surkus, H. Junge, M.-M. Pohl, J. Radnik, J. Rabeah,
H. Huan, V. Schünemann, A. Brückner, M. Beller, Science 2013, 342,
1
073–1076.
[
3] a) F. A. Westerhaus, R. V. Jagadeesh, G. Wienhöfer, M.-M. Pohl, J. Radnik,
A.-E. Surkus, J. Rabeah, K. Junge, H. Junge, M. Nielsen, A. Brückner, M.
Beller, Nat. Chem. 2013, 5, 537–543; b) Y. Cao, S. Mao, M. Li, Y. Chen, Y.
Wang, ACS Catal. 2017, 7, 8090–8112; c) P. Chen, F. Yang, A. Kostka, W.
Xia, ACS Catal. 2014, 4, 1478–1486.
6581; b) Z. Zhang, C. Yang, S. Wu, A. Wang, L. Zhao, D. Zhai, B. Ren, K.
Cao, Z. Zhou, Adv. Energy Mater. 2019, 9, 1802805.
[18] K. Shen, B. Narsu, G. Ji, H. Sun, J. Hu, Z. Liang, X. Gao, H. Li, Z. Li, B. Song,
Z. Jiang, H. Huang, J. W. Wells, F. Song, RSC Adv. 2017, 7, 13827–13835.
19] A. Bulut, M. Yurderi, İ. E. Ertas, M. Celebi, M. Kaya, M. Zahmakiran, Appl.
Catal. B: Environ. 2016, 180, 121–129.
[20] a) A. Morozan, P. Jégou, B. Jousselme, S. Palacin, Phys. Chem. Chem.
Phys. 2011, 13, 21600–21607; b) T. Cheng, H. Yu, F. Peng, H. Wang, B.
Zhang, D. Su, Catal. Sci. Technol. 2016, 6, 1007–1015.
[21] F. Zhang, C. Ma, Y. Zhang, H. Li, D. Fu, X. Du, X.-M. Zhang, J. Power
Sources 2018, 399, 89–97.
[4] a) Z. Wei, Y. Chen, J. Wang, D. Su, M. Tang, S. Mao, Y. Wang, ACS Catal.
016, 6, 5816–5822; b) R. V. Jagadeesh, K. Murugesan, A. S. Alshammari,
H. Neumann, M.-M. Pohl, J. Radnik, M. Beller, Science 2017, 358, 326–
32.
[5] a) M. Yuan, Y. Long, J. Yang, X. Hu, D. Xu, Y. Zhu, Z. Dong, ChemSusChem
018, 11, 4156–4165; b) X. Ma, Y.-X. Zhou, H. Liu, Y. Li, H.-L. Jiang, Chem.
[
2
3
2
Commun. 2016, 52, 7719–7722; c) P. Zhou, Z. Zhang, L. Jiang, C. Yu, K.
Lv, J. Sun, S. Wang, Appl. Catal. B: Environ. 2017, 210, 522–532; d) Z.
Zhao, H. Yang, Y. Li, X. Guo, Green Chem. 2014, 16, 1274–1281.
6] a) T. Schwob, R. Kempe, Angew. Chem. Int. Ed. 2016, 55, 15175–15179;
Angew. Chem. 2016, 128, 15400–15404; b) L. Liu, P. Concepción, A.
Corma, J. Catal. 2016, 340, 1–9.
[22] X. Cui, K. Liang, M. Tian, Y. Zhu, J. Ma, Z. Dong, J. Colloid Interface Sci.
2
017, 501, 231–240.
[
[23] a) E. A. Lewis, M. D. Marcinkowski, C. J. Murphy, M. L. Liriano, E. C. H.
Sykes, J. Phys. Chem. Lett. 2014, 5, 3380–3385; b) E. A. Lewis, D. Le, C. J.
Murphy, A. D. Jewell, M. F. G. Mattera, M. L. Liriano, T. S. Rahman, E. C. H.
Sykes, J. Phys. Chem. C 2012, 116, 25868–25873; c) E. A. Lewis, D. Le,
A. D. Jewell, C. J. Murphy, T. S. Rahman, E. C. H. Sykes, ACS Nano 2013, 7,
4384–4392.
[7] a) P. Zhou, L. Jiang, F. Wang, K. Deng, K. Lv, Z. Zhang, Sci. Adv. 2017, 3,
e1601945; b) R. Gao, L. Pan, Z. Li, X. Zhang, L. Wang, J.-J. Zou, Chin. J.
Catal. 2018, 39, 664–672.
[
8] a) F. Zhang, C. Zhao, S. Chen, H. Li, H. Yang, X.-M. Zhang, J. Catal. 2017,
348, 212–222; b) X. Sun, A. I. Olivos-Suarez, D. Osadchii, M. J. V. Romero,
F. Kapteijn, J. Gascon, J. Catal. 2018, 357, 20–28; c) Z. Wei, J. Wang, S.
Mao, D. Su, H. Jin, Y. Wang, F. Xu, H. Li, Y. Wang, ACS Catal. 2015, 5,
[24] T. Song, P. Ren, Y. Duan, Z. Wang, X. Chen, Y. Yang, Green Chem. 2018,
20, 4629–4637.
[25] C. Wang, J. Tuninetti, Z. Wang, C. Zhang, R. Ciganda, L. Salmon, S. Moya,
J. Ruiz, D. Astruc, J. Am. Chem. Soc. 2017, 139, 11610–11615.
4
783–4789; d) X. Wei, Z. Zhang, M. Zhou, A. Zhang, W. D. Wu, Z. Wu,
Nanoscale 2018, 10, 16839–16847.
[
9] a) K. Shen, L. Chen, J. Long, W. Zhong, Y. Li, ACS Catal. 2015, 5, 5264–
5271; b) J. Mao, W. Chen, W. Sun, Z. Chen, J. Pei, D. He, C. Lv, D. Wang,
Y. Li, Angew. Chem. Int. Ed. 2017, 129, 12133–12137; c) X. Li, Z. Wang, Z.
Zhang, G. Yang, M. Jin, Q. Chen, Y. Yin, Mater. Horiz. 2017, 4, 584–590;
d) S. Iihama, S. Furukawa, T. Komatsu, ACS Catal. 2016, 6, 742–746; e) Y.
Manuscript received: February 15, 2019
Revised manuscript received: April 2, 2019
Version of record online: ■■■, ■■■■
ChemCatChem 2019, 11, 1–9
www.chemcatchem.org
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© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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COMMUNICATIONS
Don’t stop ’till you rise to the top: A
facile yet effective approach is
proposed to construct nitrogen-
doped hierarchical porous carbon
embedded bimetallic CoCu NPs
catalyst through in-situ carbothermal
reduction, which exhibits superior
catalytic hydrogenation performance
towards various nitroaromatics and
hydrolysis of ammonia borane to
produce hydrogen under extremely
mild conditions.
F. Zhang*, Z. Li, C. Ma, X. Han, X.
Dong, Prof. Z. Dong*, X.-M. Zhang*
1 – 9
N-Doped Hierarchical Porous
Carbon Embedded Synergistic Bi-
metallic CoCu NPs with Unparal-
leled Catalytic Performance
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