Flexible and Hierarchical Metal–Organic Framework Composites for High-Performance Catalysis

Article abstract of DOI:10.1002/anie.201803096

The development of porous composite materials is of great significance for their potentially improved performance over those of individual components and extensive applications in separation, energy storage, and heterogeneous catalysis. Now mesoporous metal–organic frameworks (MOFs) with macroporous melamine foam (MF) have been integrated using a one-pot process, generating a series of MOF/MF composite materials with preserved crystallinity, hierarchical porosity, and increased stability over that of melamine foam. The MOF nanocrystals were threaded by the melamine foam networks, resembling a ball-and-stick model overall. The resulting MOF/MF composite materials were employed as an effective heterogeneous catalyst for the epoxidation of cholesteryl esters. Combining the advantages of interpenetrative mesoporous and macroporous structures, the MOF/melamine foam composite has higher dispersibility and more accessibility of catalytic sites, exhibiting excellent catalytic performance.

Full text of DOI:10.1002/anie.201803096

A Journal of the Gesellschaft Deutscher Chemiker
Angewandte
Chemie
International Edition
www.angewandte.org
Accepted Article
Title: Flexible and Hierarchical Metal-Organic Framework Composites
for High-Performance Catalysis
Authors: Ning Huang, Hannah Drake, Jialuo Li, Jiangdong Pang, Ying
Wang, Shuai Yuan, Qi Wang, Peiyu Cai, Junsheng Qin, and
Hong-Cai Zhou
This manuscript has been accepted after peer review and appears as an
Accepted Article online prior to editing, proofing, and formal publication
of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
published online in Early View as soon as possible and may be different
to this Accepted Article as a result of editing. Readers should obtain
the VoR from the journal website shown below when it is published
to ensure accuracy of information. The authors are responsible for the
content of this Accepted Article.
To be cited as: Angew. Chem. Int. Ed. 10.1002/anie.201803096
Angew. Chem. 10.1002/ange.201803096
Link to VoR: http://dx.doi.org/10.1002/anie.201803096
http://dx.doi.org/10.1002/ange.201803096

10.1002/anie.201803096
Angewandte Chemie International Edition
COMMUNICATION
Flexible and Hierarchical Metal-Organic Framework Composites
for High-Performance Catalysis
Ning Huang, Hannah Drake, Jialuo Li, Jiandong Pang, Ying Wang, Shuai Yuan, Qi Wang, Peiyu Cai,
Junsheng Qin, and Hong-Cai Zhou*
Abstract: The development of new types of porous composite
materials is of great significance owing to their potentially improved
performance over those of individual components and extensive
applications in separation, energy storage, and heterogeneous
catalysis. In this work, we integrated mesoporous metal-organic
frameworks (MOFs) with macroporous melamine foam (MF) using a
one-pot process, generating a series of MOF/MF composite materials
with preserved crystallinity, hierarchical porosity, and increased
stability over that of melamine foam. The MOF nanocrystals were
threaded by the melamine foam networks, resembling a ball-and-stick
model overall. As a proof-of-concept study, the resulting MOF/MF
composite materials were employed as an effective heterogeneous
catalyst for the epoxidation of cholesteryl esters. Combining the
advantages of interpenetrative mesoporous and macroporous
structures, the MOF/melamine foam composite provided higher
dispersibility and more accessibility of catalytic sites, exhibiting
excellent catalytic performance. This strategy constitutes an important
step forward the development of other MOF composites and
exploration of their high-performance catalysis.
MOF/enzymes,[11e] and MOF/metal nanoparticles,[11f] generating
new properties unavailable from either component. Very recently,
Wang and coworkers successfully developed the MOF/mesh,
MOF/cloth, and MOF/sponge composites via the roll-to-roll
mechanical production and utilized them for efficient particulate
matter removal.[12] Eddaoudi group reported the MOF/silica
composite by the stepwise layer-by-layer strategy.[13] Su and Zhu
groups also developed new hierarchical Al-metal-organic
aerogels based on a post-synthetic process using MOFs and
other additives.[14] However, these methods are synthetically
tedious and cannot retain the original crystalline morphology of
MOFs. We aim to develop stable MOF/foam composite materials
by a one-pot procedure, which enables the direct preparation of
high-quality composite materials. More importantly, this would
provide a general strategy to prepare MOFs for practical
applications, especially in heterogeneous catalysis over a scope
broader than ever before.
Heterogeneous catalysts have many advantages over their
homogeneous counterparts in reactor design, such as easy
operation, excellent activity, good selectivity, and catalyst
reusability. To improve the catalytic performance of MOFs, a great
variety of approaches have been explored, but it remains a
daunting challenge to create macropores in a coordination
network.[15] Considering all of these issues, we seek to grow MOF
crystals within macroporous melamine foam (MF) to form
MOF/MF composites, which possess many advantages of low
density, good mechanical capacity, excellent thermal and
chemical stability, and high void fractions. In this means, a new
dimension can be created via the combination of the inherent
micropores or mesopores with additional macropores. In addition,
the effects of the composited hierarchical structure on catalytic
activity, selectivity, and stability have been investigated. Notably,
significant improvement of catalytic performance was readily
achieved. Owing to the high chemical robustness of the MOF/MF
composites, they can be recycled more than six times without
significant loss of activity and selectivity. This strategy provided a
general strategy to prepare high-quality MOF composites and
made an essential step towards future practical applications of
MOFs.
Metal-organic frameworks (MOFs) are a class of crystalline
porous materials, which are constructed with metal or metal
clusters as nodes and organic ligands as linkers.[1] MOFs are well
known for their extraordinarily high porosity and internal surface
areas.[2] Owing to their crystalline and porous structures, MOFs
have been widely used in many application, including gas
storage,[3] gas separation,[4] heterogeneous catalysis,[5] light
emission,[6] drug delivery,[7] and proton conduction.[8] However,
most MOFs are rigid, brittle, and very easy to be crumbed.[9] In
addition, MOFs are insoluble in any solvents and have no exact
melting points, which means that they cannot be processed by
traditional solvent or heat-based techniques.[10] All of these
disadvantages have largely limited their practical applications in
various domains. To tackle this problem, tremendous efforts have
been made to hybridize MOFs with other materials, thus realizing
the combination of their advantages and circumventing
shortcomings.
successfully
A
variety of MOF composites have been
developed, such as
MOF/graphene,[11a]
MOF/graphite,[11b] MOF/carbon nanotubes,[11c] MOF/polymers,[11d]
In this work, we developed a one-pot strategy to integrate
PCN-224 and melamine foam into a hierarchical composite. As
reported previously, the crystalline structure of PCN-224 was
classified as cubic crystal system (Figure 2a, b). The MOF/MF
composite was prepared under a straightforward solvothermal
condition (Figure 1c). The macroporous melamine foam provided
abundant voids for the loading of PCN-224 (Figure 1d,e). It’s well
known that PCN-224 is constructed with Zr6 clusters and square
planar tetrakis(4-carboxyphenyl)-porphyrin (TCPP) ligands in the
space group Im3-m.[16] One Zr6 cluster is connected with six TCPP
[*]
Dr. N. Huang,[+] H. Drake,[+] J. Li, Dr. J. Pang, Dr. Y. Wang, S. Yuan,
Q. Wang, P. Cai, Dr. J. Qin, Prof. Dr. H.-C. Zhou
Department of Chemistry
Texas A&M University
College Station, Texas 77842-3012, United States
E-mail: zhou@chem.tamu.edu
Dr. Y. Wang
College of Chemistry
Tianjin Normal University
Tianjin 300387, China
ligands forming
a “she” type network, which possesses
[+]
These authors contributed equally.
Supporting information for this article is given via a link at the end of
the document.
extraordinary chemical stability and high structural tunability.
This article is protected by copyright. All rights reserved.

10.1002/anie.201803096
Angewandte Chemie International Edition
COMMUNICATION
Figure 2. a, b) FE-SEM images of PCN-224(Fe)/MF composite. c) The PXRD
patterns of PCN-224(Fe) (grey curve), PCN-224(Fe)50%/MF (purple curve),
PCN-224(Fe)100%/MF (green curve), PCN-224(Fe)150%/MF (blue curve), PCN-
224(Fe)200%/MF (red curve), and PCN-224(Fe)325%/MF (black curve). d) N2
sorption isotherms of PCN-224(Fe)50%/MF (purple curve), PCN-224(Fe)100%/MF
(green curve), PCN-224(Fe)150%/MF (blue curve), PCN-224(Fe)200%/MF (red
curve), and PCN-224(Fe)325%/MF (black curve).
retained in PCN-224(Fe)/MF, without losing the inherent
structural periodicity of crystalline materials. Thermogravimetric
analysis (TGA) result revealed the PCN-224(Fe)/MF composite
was thermally stable up to 300 °C in nitrogen (Figure S1 in the
Supporting Information). Notably, the maximum loading content
of PCN-224(Fe) is up to 325%, which is the highest value among
all the MOF composites.[12-14] As a contrast, the direct mixing of
excessive PCN-224(Fe) and melamine foam lead to a maximum
loading amount of 11%. In addition, we can precisely tune the
loading content of PCN-224(Fe) ranging from 50% to 325% by
simply adjusting feed ratios (Table S1). For example, we
successfully prepared a series of PCN-224(Fe)/MF composites
with loading contents of 50%, 100%, 150%, 200%, and 325%,
namely PCN-224(Fe)50%/MF, PCN-224(Fe)100%/MF, PCN-
224(Fe)150%/MF, PCN-224(Fe)200%/MF, and PCN-224(Fe)325%/MF,
respectively.
Figure 1. a) The topological structure of PCN-224. b) View down the tetragonal
channels of PCN-224 (black, carbon; purple, metal; blue, nitrogen; hydrogen,
omitted). c) The schematic procedure for the preparation of the PCN-224
decorated melamine foam composites. d) The photograph and chemical
formula of melamine foam. e) The FE-SEM image of the melamine foam used
in this work. f) The mixture of TCPP(Fe), ZrCl4, and benzoic acid in DMF solution
(left) and immersing the melamine foam into the solution for one-pot synthesis
(right). The melamine foam (g, h) and as-synthesized PCN-224(Fe)/MF (i, j)
could be compressed and distorted.
To obtain stable and high-quality MOF/MF composites, we initially
selected PCN-224(Fe) as a model to screen the optimum
conditions. We conducted the synthesis by assembling the
TCPP(Fe) ligand and zirconium chloride in the presence of acid-
pretreated melamine foam. The monolithic melamine foam was
totally submerged in an N,N-dimethylmethanamide (DMF)
solution of the mixture (Figure 1f). After the addition of benzoic
acid, the mixture was sealed and stored at 120 °C for 72 h. The
colourless melamine foam turned to dark brown and was
homogeneously loaded with crystalline PCN-224(Fe). Owing to
the flexible and elastic features of melamine foam, the resulting
PCN-224/MF can withstand a certain degree of compression and
exhibit elastomer characteristics (Figure 1g−j).
To investigate the crystallinity of these PCN-224(Fe)/MF
samples, powder X-ray diffraction (PXRD) was employed for full
characterization. As shown in Figure 2c, all of the PCN-
224(Fe)/MF samples exhibited strong diffraction patterns, which
were consistent with those of PCN-224(Fe). As the loading
content of PCN-224(Fe) was different in the composites, their
nitrogen uptake values deviated from that of PCN-224(Fe), with
nitrogen uptake of 198, 310, 401, 497, and 564 m2 g−1 for PCN-
224(Fe)50%/MF, PCN-224(Fe)100%/MF, PCN-224(Fe)150%/MF,
PCN-224(Fe)200%/MF, and PCN-224(Fe)325%/MF, respectively
(Figure 2d). With the same pore size of 2.0 nm,
Brunauer−Emmett−Teller (BET) surface areas for PCN-
224(Fe)50%/MF, PCN-224(Fe)100%/MF, PCN-224(Fe)150%/MF,
PCN-224(Fe)200%/MF, and PCN-224(Fe)325%/MF were calculated
Field emission scanning electron microscopy (FE-SEM)
visually revealed that the bare melamine foam network was
homogeneously decorated with PCN-224(Fe) crystal particles
(Figure 2a,b), which were penetrated through the centre by MF
fibers in a ball-and-stick mode. All the crystals adopted a cubic
morphology with an average size of about 20 µm. Different with
other MOF composites, the morphology of PCN-224 was well
This article is protected by copyright. All rights reserved.

10.1002/anie.201803096
Angewandte Chemie International Edition
COMMUNICATION
as 645, 1084, 1320, 1645, and 2210 m2 g−1, respectively (Figure
S2 and Table S2). This trend can be ascribed to the increasing
loading amount of PCN-224(Fe) in the composites. As a control
experiment, the melamine foam exhibited almost no nanoporosity
in the nitrogen sorption analysis at 77 K (Figure S3). With the
increasing loading amount of PCN-224(Fe), the macropores of
melamine foam became increasingly crowed and were partially
occupied by the crystal particles (Figure S4). The density was
evaluated by the means of measuring the mass and the volume
of these composites, ranging from 0.023 to 0.164 g cm-1 (Table
S3). The homogeneity of these composites was also confirmed
by tearing them into small pieces, in which uniform texture was
found both outside and inside (Figure S5).
Table 1. The epoxidation reaction of cholesteryl esters catalyzed
by PCN-224(M)/MF.[a,b]
Amount
(mol%)[c]
Time
(h)
Yield
(%)[d]
Entry
Catalyst
Oxidant
1
PCN-224(Ru)200%/MF
PCN-224(Ru)200%/MF
PCN-224(Ru)200%/MF
PCN-224(Ru)200%/MF
PCN-224(Ru)200%/MF
PCN-224(Fe)200%/MF
PCN-224(Co)200%/MF
PCN-224(Ni)200%/MF
PCN-224(H2)200%/MF
Melamine foam
2
2
2
1
5
2
2
2
2
−
2
2
2
2
2
2
Cl2pyNO
PhIO
36
36
36
45
36
72
72
72
72
72
36
36
32
30
40
40
92
73
15
90
92
34
41
0
2
3
O2
4
Cl2pyNO
Cl2pyNO
Cl2pyNO
Cl2pyNO
Cl2pyNO
Cl2pyNO
Cl2pyNO
Cl2pyNO
Cl2pyNO
Cl2pyNO
Cl2pyNO
Cl2pyNO
Cl2pyNO
5
6
7
8
9
0
10
11
12
13[e]
14[f]
15[g]
16[h]
0
Figure 3. The SEM images of PCN-224(Ni)200%/MF (a, b), PCN-224(H2)200%/MF
(c, d), PCN-224(Co)200%/MF (e, f), and PCN-224(Ru)200%/MF (g, h).
PCN-224(Ru)
56
42
92
92
90
93
TCPP(Ru)
Metalloporphyrins are widely employed as catalysts for the
epoxidation reaction of unsaturated alkenes.[17] To investigate the
advantages of the MOF/melamine foam composites in
heterogeneous catalysis, other PCN-224(M)200%/MF (M = Ni, H2,
Co, and Ru) with different metal centres were prepared and
employed to screen the optimum conditions in the epoxidation of
cis-stilbene (Table S4). Similar with the properties of PCN-224
(Fe)200%/MF, PCN-224(M)200%/MF (M = Ni, H2, Co, and Ru)
samples displayed good crystallinity and high porosity (Figures
S6 and S7). Nitrogen sorption isotherm at 77 K revealed that their
BET surface areas were 1704, 1682, 1655, and 1623 m2 g−1 for
PCN-224(Ru)200%/MF
PCN-224(Ru)200%/MF
PCN-224(Ru)200%/MF
PCN-224(Ru)200%/MF
[a] All reactions were carried out in CH2Cl2 at room temperature. [b]
Catalyst:cholesteryl esters:(Cl2pyNO) molar ratio=1:50:100. [c] The amount
of catalyst. [d] Yield of isolated product based on the amount of the substrate
consumed. [e] PCN-224(Ru)200%/MF with 1 µm crystals as catalyst. [f] PCN-
224(Ru)200%/MF with 600 nm crystals as catalyst. [g] The substrate was
cholesteryl palmitate. [h] The substrate was cholesteryl benzoate.
PCN-224(Ni)200%/MF,
PCN-224(H2)200%/MF,
PCN-
224(Co)200%/MF, and PCN-224(Ru)200%/MF, respectively (Figure
S8). The morphology of these PCN-224(M)200%/MF (M = Ni, H2,
Co, and Ru) samples was investigated by FE-SEM to visualize
their hierarchical structures. As shown in Figure 3, the PCN-
224(M) crystals were closely anchored on the melamine foam
fibers. Scanning electron microscopy coupled with energy
dispersive X-ray (SEM/EDX) indicated the content of Fe, Ni, Co,
and Ru were 4.98%, 5.15%, 5.41, and 8.65%, which were
consistent with their theoretical values (Figures S9−S13). The
chemical stability of PCN-224(M)200%/MF (M = Fe, Ni, H2, Co, and
Ru) were also examined in different solvent conditions, including
water, ethanol, DMF, THF, and hexane. All of the MOF/MF
composites can stay stable in these solutions for 7 days without
any loss of PCN-224 powder (Figure S14). Combining the good
crystallinity, high porosity, and excellent stability, PCN-224/MF
exhibited a broad prospect in heterogeneous catalysis.
Cholesterol plays a vital role in the constitution of cell
membranes and controls the state of membrane fluidity. In many
cases, certain cholesterol derivatives are powerful medicines for
human diseases. Therefore, the development of efficient
synthetic methods for cholesterol derivatives are important for the
improvement of human health. From the economic viewpoint, the
catalytic epoxidation of unsaturated cholesteryl esters is of great
significance to produce metabolites in the pharmaceutical
industry. Although several effective catalytic transformation have
been developed, most of the catalysts are homogeneous noble
metal complexes, which are quite expensive and difficult to be
recycled.[18] The porous heterogeneous catalysts are promising to
address this problem. The exploitation of high-efficient
macroporous catalysts for epoxidation of unsaturated cholesteryl
esters remains an enormous challenge. Inspired by the
This article is protected by copyright. All rights reserved.

10.1002/anie.201803096
Angewandte Chemie International Edition
COMMUNICATION
considerable efficiency of PCN-224(M)200%/MF catalysts in the
epoxidation of cis-stilbene, we attempted to investigate their
catalytic performance in the epoxidation tranformation of
cholesteryl esters.
clearly demonstrated that both the mesopores and the
macropores contributed to the extinguished catalytic performance
of PCN-224(Ru)200%/MF.
To investigate the effects of crystal sizes on catalytic
performance, we prepared two additional PCN-224(Ru)200%/MF
samples with smaller crystal sizes (1 µm and 600 nm, Figures S17
and S18). In the presence of PCN-224(Ru)200%/MF with 1 µm and
600 nm crystals, the same yield of 92% can be obtained after 32
h and 30 h, respectively (Table 1, entry 13 and 14). The shorter
reaction time reveals that PCN-224(Ru)200%/MF with smaller
crystal sizes exhibited better catalytic performance than the one
with large crystals (Table 1, entry 1). However, when the crystal
size decreased to the nanoscale, PCN-224(Ru) was just coated
on the surface of MF matrix. The MOFs were very easy to strip off
from MF matrix due to the weak fixation ability (Figure S19). Even
one-time catalytic use can lead to significant loss of MOF powder,
which greatly limits its recyclability in practical applications.
Based on the flexibility and elasticity of PCN-224(M)/MF, we
compressed and filled the composites into glass columns for
conventional separation and recycling use (Figure S15). Owing to
the open-cell macroporous structures and uniformly distributed
catalytic active sites, PCN-224(M) /MF exhibited an exceptional
catalytic performance in the epoxidation of cholesteryl esters. As
shown in Table 1, we treated cholesteryl acetate with 2,6-
dichloropyridine N-oxide (Cl2pyNO) in dichloromethane in the
presence of 2 mol% of PCN-224(Ru)200%/MF as catalyst (Table 1,
entry 1). Under such conditions, an excellent yield (92%) of
corresponding epoxide was obtained after 36 h. However, lower
yield of 73% and 15% was obtained in the presence of PhIO and
O2 as oxidants, respectively (Table 1, entry 2 and 3). This result
indicated that Cl2pyNO was the prime oxidant for the epoxidation
transformation. To screen the optimum catalyst amount, we
adjusted the dosage of PCN-224(Ru)200%/MF as 1 mol% and 5
mol%. When the amount of PCN-224(Ru)200%/MF was reduced to
1 mol%, a lower yield of 90% was achieved after 45 h (Table 1,
entry 4). Meanwhile, the same yield of 92% was observed in the
presence of 5 mol% PCN-224(Ru)200%/MF (Table 1, entry 5). As
control experiments, PCN-224(Fe)200%/MF, PCN-224(Co)200%/MF,
PCN-224(Ni)200%/MF, PCN-224(H2)200%/MF, bare melamine foam,
and powdered PCN-224(Ru) were employed as catalysts for the
epoxidation reaction (Table 1, entry 6−11). However, after 72 h,
PCN-224(Fe)/MF and PCN-224(Co)/MF produced the epoxide
product in the yield of 34% and 41%, respectively (Table 1, entry
Remarkably, the PCN-224(Ru)200%/MF composite also
displayed considerable catalytic efficiency for the epoxidation of
cholesteryl palmitate and cholesteryl benzoate with high yield of
90% and 93% (Table 1, entry 15 and 16), respectively. On
account of the exceptional chemical and mechanical stability of
PCN-224/MF composites, the catalyst PCN-224(Ru)200%/MF can
be recycled more than six times. After each cycle of catalytic
epoxidation, PCN-224(Ru)200%/MF composite could be easily
separated and recovered by washing with eluents. The recycling
of the PCN-224(Ru)200%/MF catalyst in totally six runs did not bring
out significant loss of its original catalytic activity (Figure S20). In
addition, it can be proven that the crystallinity and porosity of
PCN-224(Ru)200%/MF were well maintained from the PXRD
patterns and N2 sorption isotherms (Figures S21 and S22).
6
and 7). PCN-224(Ni)200%/MF, PCN-224(H2)200%/MF, and
melamine foam exhibited no catalytic effects on the epoxidation
transformation (Table 1, entry 8−10), which revealed their
chemical inertness in the catalysis. To make the control
experiment more comparable, we prepared powdery PCN-
224(Ru) samples with the same crystal size with those in PCN-
224(Ru)200%/MF. All the crystals of powdery PCN-224(Ru)
aggregate in masses (Figure S16), which reduced the
accessibility to catalytic sites and greatly limited the intergranular
diffusion of substrates. Under the same conditions, the powdery
PCN-224(Ru) and the TCPP(Ru) ligand generated the
epoxidation product in the yield of 56% and 42%, respectively,
which was much lower than that of PCN-224(Ru)200%/MF
composite (Table 1, entry 11 and 12). Compared with the
TCPP(Ru) ligand, PCN-224(Ru) lead to a higher yield on account
of the enrichment of substrates within the mesopores. In addition,
all the epoxidation reactions were conducted in the glass column
filled with PCN-224(Ru)200%/MF composites or powdery PCN-
224(Ru) without stirring. Under such conditions, the catalytic
centres in PCN-224(Ru)200%/MF were evenly distributed in the
whole reaction system, while the powdery PCN-224(Ru)
accumulated at the bottom. Therefore, PCN-224(Ru)200%/MF
exhibited great superiority over its PCN-224(Ru) counterpart
owing to the higher dispersibility and more accessibility of catalytic
sites. It seems no matter that PCN-224(Ru) or PCN-
224(Ru)200%/MF composite was used, the high porous structure
could increase the overall reaction rate, and further leading to an
enhanced catalytic efficiency. Therefore, all of these results
In summary, we have developed a one-pot strategy for the
preparation of hierarchical MOF/melamine foam composites,
wherein MOF crystal nanoparticles were decorated on the fibers
of the melamine foam in a ball-and-stick model. The bottom-up
strategy is possible to be broadly applied to many other MOFs
and substrates. In addition, the combination of mesopores and
macropores in the MOF/melamine foam composite was achieved.
The specific MOF/melamine foam composites have high stability,
hierarchical porosity, flexible and elastic texture, which are
significantly favourable for heterogeneous catalysis. Finally, this
work highlighted the distinguished catalytic performance of
MOF/melamine foam for the epoxidation of cholesteryl esters.
The additional macroporous melamine foam contributed greatly
to the diffusion process and positively improved the catalytic
activity of MOFs. This strategy would be extensively employed in
the development of functional MOF composite materials and high-
performance heterogeneous catalysts.
Acknowledgements
The gas adsorption−desorption studies of this research were
supported by the Center for Gas Separations Relevant to Clean
Energy Technologies, an Energy Frontier Research Center
funded by the U.S. Department of Energy, Office of Science,
Office of Basic Energy Sciences, under Award Number
This article is protected by copyright. All rights reserved.

10.1002/anie.201803096
Angewandte Chemie International Edition
COMMUNICATION
[9]
Q.-G. Zhai, X. Bu, X. Zhao, D.-S. Li, P. Feng, Acc. Chem. Res. 2017, 50,
407−417.
DESC0001015. Structural analyses were supported as part of
U.S. Department of Energy Hydrogen and Fuel Cell Program
under Award Number DEEE-0007049. We also acknowledge the
financial support from the U.S. Department of Energy Office of
Fossil Energy, National Energy Technology Laboratory (DE-
FE0026472), and Qatar National Research Fund (NPRP9-377-1-
080).
[10] Q.-L. Zhu, Q. Xu, Chem. Soc. Rev. 2014, 43, 5468−5512.
[11] a) W. Xia, C. Qu, Z. Liang, B. Zhao, S. Dai, B. Qiu, Y. Jiao, Q. Zhang, X.
Huang, W. Guo, D. Dang, R. Zou, D. Xia, Q. Xu, M. Liu, Nano Lett. 2017,
17, 2788−2795; b) C. Petit, T. J. Bandosz, Adv. Mater. 2009, 21,
4753−4757; c) Y. Mao, G. Li, Y. Guo, Z. Li, C. Liang, X. Peng, Z. Lin, Nat.
Commun. 2017, 8, 14628; d) J. Huo, M. Marcello, A. Garai, D. Bradshaw,
Adv. Mater. 2013, 25, 2717−2722; e) X. Lian, Y. Fang, E. Joseph, Q.
Wang, J. Li, S. Banerjee, C. Lollar, X. Wang, H.-C. Zhou, Chem. Soc.
Rev. 2017, 46, 3386−3401; f) Q. Yang, Q. Xu, H.-L. Jiang, Chem. Soc.
Rev. 2017, 46, 4774−4808.
Keywords: metal-organic frameworks • porous materials •
composite materials • heterogeneous catalysis
[12] a) Y. Chen, S. Zhang, S. Cao, S. Li, F. Chen, S. Yuan, C. Xu, J. Zhou, X.
Feng, X. Ma, B. Wang, Adv. Mater. 2017, 29, 1606221; b) Y. Chen, F.
Chen, S. Zhang, Y. Cai, S. Cao, S. Li, W. Zhao, S. Yuan, X. Feng, A.
Cao, X. Ma, B. Wang, J. Am. Chem. Soc. 2017, 139, 16482−16485.
[13] a) O. Shekhah, L. L. Fu, R. Sougrat, Y. Belmabkhout, A. J. Cairns, E. P.
Giannelis, M. Eddaoudi, Chem. Commun. 2012, 48, 11434−11436; b) Y.
L. Hu, H. X. Lian, L. J. Zhou, G. K. Li, Anal. Chem. 2015, 87, 406−412.
[14] a) L. Li, S. L. Xiang, S. Q. Cao, J. Y. Zhang, G. F. Ouyang, L. P. Chen,
C. Y. Su, Nat. Commun. 2013, 4, 1774; b) H. Zhu, X. Yang, E. D.
Cranston, S. P. Zhu, Adv. Mater. 2016, 28, 7652−7657.
[1]
[2]
a) H.-C. Zhou, J. R. Long, O. M. Yaghi, Chem. Rev. 2012, 112, 673−674;
b) Y. He, B. Li, M. O'Keeffe, B. Chen, Chem. Soc. Rev. 2014, 43,
5618−5656.
a) A. Schoedel, M. Li, D. Li, M. O'Keeffe, O. M. Yaghi, Chem. Rev., 2016,
116, 12466−12535; b) A. J. Howarth, Y. Liu, P. Li, Z. Li, T. C. Wang, J.
T. Hupp, O. K. Farha, Nat. Rev. Mater. 2016, 1, 15018.
[3]
[4]
Y. Lin, C. Kong, Q. Zhang, L. Chen, Adv. Energy Mater. 2017, 7, 1601296.
X. Cui, K. Chen, H. Xing, Q. Yang, R. Krishna, Z. Bao, H. Wu, W. Zhou,
X. Dong, Y. Han, B. Li, Q. Ren, M. J. Zaworotko, B. Chen, Science 2016,
353, 141−144.
[15] H. Deng, S. Grunder, K. E. Cordova1, C. Valente, H. Furukawa, M.
Hmadeh, F. Gándara, A. C. Whalley, Z. Liu, S. Asahina, H. Kazumori, M.
O’Keeffe, O. Terasaki, J. F. Stoddart, O. M. Yaghi, Science 2012, 336,
1018−1023.
[5]
[6]
a) P. Ji, J. B. Solomon, Z. Lin, A. Johnson , R. F. Jordan, W. Lin, J. Am.
Chem. Soc. 2017, 139, 11325−11328; b) N. Huang, S. Yuan, H. Drake,
X. Yang, J. Pang, J. Qin, J. Li, Y. Zhang, Q. Wang, D. Jiang, H.-C. Zhou,
J. Am. Chem. Soc. 2017, 139, 18590−18597.
[16] D. Feng, W.-C. Chung, Z. Wei, Z.-Y. Gu, H.-L. Jiang, Y.-P. Chen, D. J.
Darensbourg, H.-C. Zhou, J. Am. Chem. Soc. 2013, 135, 17105−17110.
[17] a) G. Grigoropouloua, J. H. Clark, J. A. Elings, Green Chem. 2003, 5,
1−7; b) T. G. Traylor, A. R. Miksztal, J. Am. Chem. Soc. 1989, 111,
7443−7448.
a) Y. Guo, X. Feng, T. Han, S. Wang, Z. Lin, Y. Dong, B. Wang, J. Am.
Chem. Soc. 2014, 136, 15485−15488; b) Y. Fang, W. Liu, S. J. Teat, G.
Dey, Z. Shen, L. An, D. Yu, L. Wang, D. M. O'Carroll, J. Li, Adv. Funct.
Mater. 2017, 27, 1603444.
[7]
[8]
a) M.-X. Wu, Y.-W. Yang, Adv. Mater. 2017, 29, 1606134; b) L. Wang,
M. Zheng, Z. Xie, J. Mater. Chem. B 2018, 6, 707−717.
[18] a) J. L. Zhang, H. B. Zhou, J. S. Huang, C. M. Che, Chem. Eur. J. 2002,
8, 1554−1562; b) D. Shabashov, M. P. Doyle, Tetrahedron 2013, 69,
10009−10013.
G. K. H. Shimizu, J. M. Taylor, S. Kim, Science 2013, 341, 354−355.
This article is protected by copyright. All rights reserved.

10.1002/anie.201803096
Angewandte Chemie International Edition
COMMUNICATION
COMMUNICATION
A series of flexible and hierarchical
MOF composite have been developed
by integrating mesoporous MOFs with
macroporous melamine foam using a
one-pot process. These composite
materials can be employed as an
effective heterogeneous catalyst for
epoxidation reactions.
Ning Huang, Hannah Drake, Jialuo Li,
Jiandong Pang, Ying Wang, Shuai
Yuan, Qi Wang, Peiyu Cai, Junsheng
Qin, Hong-Cai Zhou*
Page No. – Page No.
Flexible and Hierarchical Metal-
Organic Framework Composites for
High-Performance Catalysis
This article is protected by copyright. All rights reserved.