Encapsulation of Molybdenum Carbide Nanoclusters inside Zeolite Micropores Enables Synergistic Bifunctional Catalysis for Anisole Hydrodeoxygenation

Article abstract of DOI:10.1021/acscatal.7b03175

Molybdenum carbide (MoC_x) nanoclusters were encapsulated inside the micropores of aluminosilicate FAU zeolites to generate highly active and selective bifunctional catalyst for the hydrodeoxygenation of anisole. Interatomic correlations obtained with differential pair distribution function analysis confirmed the intraparticle structure and the uniform size of the MoC_x nanoclusters. The reactivity data showed the preferential production of alkylated aromatics (such as toluene and xylene) over benzene during the hydrodeoxygenation of anisole as well as the minimization of unwanted CH₄ formation. Control experiments demonstrated the importance of MoC_x encapsulation to generate an efficient bifunctional catalyst with superior carbon utilization and on-stream stability.

Full text of DOI:10.1021/acscatal.7b03175

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Letter
Encapsulation of molybdenum carbide nanoclusters inside zeolite micropores
enables synergistic bifunctional catalysis for anisole hydrodeoxygenation
Takayuki Iida, Manish Shetty, Karthick Murugappan, Zhenshu
Wang, Koji Ohara, Toru Wakihara, and Yuriy Roman-Leshkov
ACS Catal., Just Accepted Manuscript • DOI: 10.1021/acscatal.7b03175 • Publication Date (Web): 20 Oct 2017
Downloaded from http://pubs.acs.org on October 20, 2017
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ACS Catalysis
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Encapsulation of Molybdenum Carbide Nanoclusters inside Zeolite Mi-
cropores Enables Synergistic Bifunctional Catalysis for Anisole Hydro-
deoxygenation
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Takayuki Iida , Manish Shetty , Karthick Murugappan , Zhenshu Wang , Koji Ohara , Toru Waki-
1*
2*
hara , and Yuriy Román-Leshkov
1) Department of Chemical System Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656,
Japan
2
) Department of Chemical Engineering, Massachusetts Institute of Technology, 25 Ames Street, Cambridge, Massa-
chusetts 02139, United States of America
) Japan Synchrotron Radiation Research Institute/SPring-8, Kouto 1-1-1, Sayo-gun, Hyogo 679-5198, Japan
3
ABSTRACT: Molybdenum carbide (MoC ) nanoclusters were encapsulated inside the micropores of aluminosilicate FAU
x
zeolites to generate highly active and selective bifunctional catalyst for the hydrodeoxygenation of anisole. Interatomic cor-
relations obtained with differential pair distribution function analysis confirmed the intraparticle structure and the uniform
size of the MoC
x
nanoclusters. The reactivity data showed the preferential production of alkylated aromatics (such as tolu-
for-
encapsulation to generate an efficient bifunctional cata-
ene and xylene) over benzene during the hydrodeoxygenation of anisole as well as the minimization of unwanted CH
mation. Control experiments demonstrated the importance of MoC
lyst with superior carbon utilization and on-stream stability.
4
x
Keywords: Hydrodeoxygenation, bifunctional catalyst, zeolite, carbide, pair distribution function
Bifunctional catalysts have been reported to open up
remarkable reaction routes to desired products at high
yields in multi-step reactions . Metal supported zeolites
structure. The limited loadings (usually ~1 wt%) and the
small particle sizes prevent the use of conventional analyt-
ical techniques such as powder X-ray diffraction (PXRD) .
1
14
are promising materials for acid/metal bifunctional cataly-
sis, as exemplified in the simultaneous Fischer-
Similarly, while transmission electron microscopy (TEM)
can provide information regarding the particle size and
morphology, other structural information is limited. Ex-
2
Tropsch/hydrocracking , as well as in the hydroisomeriza-
3
2
3
15
tion of alkanes using cobalt and platinum metals sup-
ported on zeolites, respectively. The efficient combination
of zeolite pore confinement effects with nanoparticles hav-
ing unconventional redox-active sites, such as transition
metal carbides, will provide further possibilities for devel-
oping new bifunctional catalysts. For some reactions, early
transition metal carbides have shown similar catalytic ac-
tended X-ray absorption fine structure (EXAFS) and
16
chemisorption are powerful tools in characterizing
nanoclusters composed of single metallic element, provid-
ing information regarding crystal structure and particle
size, but the accurate interpretation of these measure-
ments becomes more challenging for heterometallic nano-
particles. For example, CO chemisorption values on a car-
bide are highly dependent on synthesis conditions and the
4
tivity to that of group VIII noble metals , and are gaining
5
,6
more attention in applications such as electrocatalysis ,
nature of the surface (e.g., mild passivation or presence of
hydrodeoxygenation7 and Fischer-Tropsch chemistry
,8
9,10
.
coke)
17,18
, and thereby, dispersion measurements may
Indeed, various transition metal carbides supported on
provide inaccurate results. The development of reliable
characterization tools for carbide nanoclusters is critical
for the design and implementation of these materials in
various catalytic processes.
ZSM-5 zeolites are the preferred catalysts for methane
dehydroaromatization1
1–13
.
The efficient bifunctionality of these materials hinges on
the molecular proximity of the metallic sites of the nano-
In this work, we first encapsulated molybdenum carbide
2
,13
particles with the Brønsted acid sites of the zeolites
.
(MoC ) nanoclusters within the pores of zeolites with the
x
Therefore, the controlled synthesis and detailed character-
ization of the encapsulated metallic species (usually < 1
nm in diameter) is of critical importance to direct targeted
reaction pathways. A major bottleneck for achieving these
goals lies in the lack of methodologies for understanding
the structural nature of the metallic nanoclusters, such as
the particle size distribution and atomic-scale intraparticle
faujasite (FAU) topology and then used pair distribution
function (PDF) analysis to conduct a detailed characteriza-
tion of their structures. While the formation of MoC
x
spe-
cies inside the zeolites pores has been demonstrated in
1
1–13
prior studies
, their particle size distribution and intra-
1
9
particle atomic arrangement have remained ambiguous .
PDF represents the probability of finding an interatomic
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distance inside an unit volume, and has conventionally
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ꢀꢁꢂꢃꢄꢅꢆ ≅ ꢇ ꢀ ꢄꢅꢆ ꢈ ꢇ ꢀ ꢄꢅꢆ ⋯ ꢄ1ꢆ
ꢁ
ꢁ
ꢃ ꢃ
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been used to describe disordered structures that are not
amenable to conventional diffraction techniques (e.g.,
ꢉꢇ ꢀ ꢄꢅꢆ ≅ ꢀ ꢄꢅꢆ ꢊ ꢇ ꢀ ꢄꢅꢆ ⋯ ꢄ1ꢆ′
ꢁ
ꢁ
ꢁꢂꢃ
ꢃ ꢃ
where A and B represent specific phases (in this case A
represents the MoC phase and B represents the FAU zeo-
2
0
amorphous vitreous glasses) . The availability of this
method for describing structural arrangements at distanc-
es beyond those reliably quantifiable by EXAFS (>5 Å) has
allowed the acquisition of information on other crystalline
x
lite phase, A ꢈ B represents the mixture of the two phases,
and ꢇ and ꢇ are coefficients). The calculated d-PDF result
ꢁ
ꢃ
for MoC
physical mixture of Mo
Mo weight loading is shown in Figure 2 B. To account for
the correlation peaks, the theoretical G(r) of Mo
phase) was calculated using PDFgui software , and is
shown in Figure 2 C for comparison. Ziman-Faber total
structure factors, S(Q), used for the calculation of the PDFs
are summarized in Figure S2. Correlations corresponding
x
/FAU is shown in Figure 2 A, and that for the
2
1,22
nanostructures including heterometallic nanoparticles
2
C and FAU zeolite with equivalent
2
3
and even disorders in bulk crystals . We investigated the
encapsulated MoC nanoclusters as catalysts for the vapor
x
2
C (hcp
phase hydrodeoxygenation (HDO) of anisole, a biomass-
based model compound with methoxy benzene motif
prevalent in lignin’s structure2 . The use of pristine mo-
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4,25
lybdenum carbide (Mo C) catalysts for this reactions has
2
been shown to produce benzene and methane as the main
products with high selectivity and minimal formation of
to the Mo
2
C phase were observed up to r ~7 Å for
MoC /FAU (shown with black dotted lines), but were not
x
2
5
ring-saturated byproducts . Zeolites are known to be ef-
fective deoxygenation agents for pyrolysis oil, at the ex-
observed at longer distances (shown with red dotted lines)
showing that the nanoclusters only possess structural or-
dering up to around 7 Å, corresponding no larger than
three unit cells. On the contrary, the d-PDF of the physical
mixture possessed correlation ranging beyond this dis-
tance, confirming that if a bulk structure had formed, all
the theoretical correlations in this distance range should
be apparent. Thus, these data are in agreement with the
presence of ~10 Å sized nanoclusters as observed in the
TEM images shown in Figure 2 D. Assignment of the corre-
2
6
pense of producing large amounts of coke . We show that
the bifunctional MoC /FAU catalyst displayed stable
trans)alkylation and hydrodeoxygenation activity, gener-
x
(
ating a high proportion of alkylated aromatics (alkylated
aromatics/benzene ratio ~2.9 C-mol%), while minimizing
the formation of undesirable products, namely methane,
due to close interaction between strong zeolitic Brønsted
acid sites and carbidic metallic sites (Figure 1).
lation peaks in Mo C were made using the PDFgui soft-
2
2
8
ware , and most correlations visible were found to origi-
nate from Mo-C correlations (at 2.0 Å) or Mo-Mo (other
correlations shown with dotted lines) due to the relatively
large X-ray scattering factor by Mo compared to C (Figure
S3). Further, correlations corresponding to hcp Mo
phase were confirmed in the d-PDF of the physical mixture
wherein standalone bulk Mo
of the zeolite crystal.
2
C
2
C species are present outside
Figure 1. Bifunctional anisole conversion by MoC
lated FAU zeolite catalyst for producing alkylated aromatics
and C ~C light gas elements by the combination of zeolitic
Brønsted acid sites and MoC deoxygenation sites.
x
encapsu-
2
5
x
The MoC
ion exchange of Mo6+ with (NH
a carburization treatment under CH
x
/FAU catalysts were synthesized by solid state
Mo O followed by
flow at 973 K.
4
)
6
7
O
and H
24∙4H
2
4
2
The Si/Al ratio of the zeolite was 15, and the Mo/Al ratio
was fixed to 0.5, resulting in a Mo loading of 5 wt%. Pris-
tine Mo
NH Mo
2
C
was prepared by carburization of
O at 923K for 3 h. Detailed catalyst prep-
(
4
)
6
7
O
24∙4H
2
aration procedures are summarized in the Supporting In-
formation.
As expected, conventional PXRD patterns associated
with Mo
Figure S1). Therefore, structural characterization of MoC
species was performed using differential pair distribution
2
C were not detected in the MoC
x
/FAU samples
(
x
2
2,27
function (d-PDF)
, an applied form of PDF analysis use-
Figure 2. A) Pair distribution function, G(r), of MoC
parent FAU and calculated d-PDF of occluded MoC element,
B) Pair distribution function, G(r), of a physical mixture of
Mo C and FAU (5 wt% Mo), parent FAU and calculated d-PDF
of Mo C element, C) Comparison of d-PDF results with the
simulated pair distribution function, G(r), of Mo C (hcp phase)
x
/FAU,
ful for determining specific phases in binary mixtures. This
technique involves taking the difference between the pair
distribution functions, G(r), of the mixture and the ad-
mixed secondary phase as shown in Eqs (1) and (1)’ be-
low:
x
2
2
2
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ACS Catalysis
2
8
using PDFgui software , and D) Typical TEM image of
MoC /FAU. Correlations corresponding to Mo C are shown
ergy with acid sites, control reactions were also performed
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x
2
using a pristine Mo C, a parent FAU zeolite, and a physical
2
with dotted lines, and the correlations assigned to MoO
cies are marked with an asterisk(*).
x
spe-
mixture of Mo
and/or Brønsted acid site loadings (designated as
Mo C+FAU; site count was performed by CO chemisorption
and NH -TPD, respectively, and the results are summa-
rized in Table S4). To assess the effectiveness of MoC /FAU
2
C and FAU zeolite with identical metal
2
3
The PDF analysis of the MoC
relations that did not belong to the Mo
and 4.4 Å (shown with asterisks(*)). A comparison with
various control materials including bcc Mo(0), MoO , and
MoO (Figure S4) confirms that the observed peaks match
those of MoO species, which are likely located on the sur-
face of the carbide as a passivation layer. The absence of
correlation peaks at r = 2.7 and 3.2 Å corresponding to
Mo(0) (bcc) denotes that any metallic molybdenum spe-
cies present in the sample are below the detection limit.
These data are in agreement with X-ray photoelectron
spectroscopy (XPS) data probing molybdenum oxidation
states of surface passivated MoC
which similar amounts of Mo2+ species was observed with
the bulk surface-passivated Mo C sample (Figure S5). A
PDF comparison with the orthorhombic Mo C and α-MoC1-x
phases showed that distinguishing the hcp phase with the
orthorhombic Mo C phase is difficult through PDF analysis
x
/FAU material showed cor-
x
2
C phase at r = 3.3
catalysts on the formation of alkylated aromatics in com-
parison to benzene, the alkylation ratio was defined as
follows:
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Alkylationꢉratio
x
∑
ProducedꢉalkylatedꢉaromaticsꢉꢌC ꢊ mol%ꢍ
ꢋꢉ
ProducedꢉbenzeneꢉꢌC ꢊ mol%ꢍ
All the catalysts used were carburized in-situ at 973 K un-
der a CH /H atmosphere before the reaction to avoid the
4
2
formation of an oxide passivation layer prior to the intro-
duction of the feed.
x
/FAU at Mo 3d band, in
For all the catalysts, the conversion (Figure 3) and the
product selectivity values (Figure S8-S11) reached steady
state after ca. 1000 min on stream. Note that under identi-
cal reaction conditions and similar number of active sites,
2
2
the MoC
x
/FAU catalyst maintained high conversions, typi-
C+FAU
2
cally above ~97%, whereas the conversion of Mo
2
due to the high similarity in the peak positions of the two
phases (also the case with PXRD ), whereas the presence
of α-MoC1-x phase can be tentatively ruled out by compar-
ing the number of peaks between r = 5.8 ~ 6.2 Å (Figure
S6). Since it is difficult to unambiguously assign the stoi-
chiometry of the nanocluster and since it is not possible to
assign a crystal structure to a solid that does not possess
settled around ~61% after 1200 min of reaction after
reaching steady state, thereby displaying apparent higher
reactivity and stability by encapsulation.
8
diffraction patterns, the term MoC
x
is used herein to de-
scribe these moieties. The N physisorption data revealed
2
the decrease in micropore volume from 0.24 (FAU) to 0.21
-1
cc g (MoC
x
/FAU), showing the encapsulation of the MoC
x
nanoclusters in the zeolite micropores (Figure S7, and Ta-
ble S3). Taken together, our data imply that phase-pure
MoC nanoclusters of ~1 nm in size were effectively encap-
x
sulated within the pores of FAU. Clearly, the capability of
PDF analyses to extract the structural information up to 10
Å is essential for describing the architecture of the encap-
sulated MoC nanoclusters. To the best of our knowledge,
x
this represents the first example of a pair distribution
function analysis applied for the structural characteriza-
tion of transition metal carbide nanoclusters.
Figure 3. Conversion time profile of anisole over MoC
x
/FAU,
pristine Mo C, parent FAU, and Mo C+FAU catalysts. All cata-
2
2
MoC /FAU was used for the coupled HDO and alkylation
x
lysts possess same metal and/or Brønsted acid site loadings.
Reaction conditions: Reaction temperature:523 K, Anisole
of anisole with the aim to obtain a higher selectivity to al-
kylated aromatic groups (i.e. toluene, xylene etc.) in place
of the benzene/methane mixture traditionally obtained
feed: 150 μl/h, Catalyst loading: 750 mg for MoC
mg for Mo C, 600 mg for parent FAU, 922 mg for Mo
Total = 1.013 bar, panisole = 0.0079 bar, and balance H
x
/FAU, 322
2
2
C+FAU,
with bulk Mo
2
C catalysts. The reaction was performed at
p
2
.
5
23 K, with pTotal = 1.013 bar, panisole = 0.0079 bar and bal-
ance H , under the absence of external and internal diffu-
2
The product distribution was significantly different
across all samples (Figure 4). For MoC /FAU, a significant
sion limitations (detailed experimental conditions are
summarized in the SI). The product distribution consisted
of benzene, toluene, alkylated aromatics C8+ (i.e. ethylben-
zene, xylenes and other deoxygenated aromatics with
more than eight carbons), phenol, alkylated phenols (phe-
nolic compounds with more than seven carbon atoms such
as cresols), alkylated anisoles (i.e. methyl anisole), and
light gas C5- (aliphatic hydrocarbons with carbon numbers
between one and five such as methane and ethane). To
understand the role of carbide encapsulation and its syn-
x
amount of alkylated aromatics was observed, with an al-
kylation ratio of 2.9 based on a yield of 17 C-mol% for al-
kylated products vs 5.8 C-mol% for benzene. This value
was maintained throughout the duration of the experi-
ment. In contrast, the experiment using the FAU zeolite
generated exclusively phenols and alkylated anisoles, both
of which are products formed by (trans)alkylation reaction
catalyzed by the Brønsted acid sites of the zeolites, thus
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Page 4 of 7
showing the lack of HDO reactivity by parent zeolite cata-
lyst. This observation confirms that MoC species are re-
gas C5- fraction (Figure 5 A)). This result is in stark contrast
to bulk Mo C catalysts, which showed selectivity values of
12 C-mol% to methane . The reaction pathway to gener-
ate C ~C light gas elements was investigated by monitor-
ing the aliphatic carbon/benzene ring molar ratio
throughout the reaction. We note that since the aim of the
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2
25
sponsible for the HDO reactivity. Bifunctional catalysis by
different materials has been performed for anisole HDO
2
5
2
9–33
reactions
(MoO /ZrO
, with maximum alkylation ratios only ~1.8
3
3
3
2
) . Evidently, the MoC /FAU catalyst is a high-
x
ly effective bifunctional catalyst with enhanced
HDO/alkylation performance over current state of the art
calculation was to elucidate the origin of C
2
~C elements,
5
cyclohexanes were lumped in into the aromatics portion
because they are produced by the hydrogenation of the
aromatic rings. As seen in Figure 5 B, the aliphatic car-
bon/benzene ring molar ratio was approximately 1
throughout the entire reaction, thereby suggesting that the
catalysts for anisole upgrading. While the Mo C+FAU mix-
2
ture also formed alkylated aromatics as products, the al-
kylation ratio only reached a value of 0.47, which is on par
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0
2
9–33
with other bifunctional catalysts
ity to alkylated anisoles was significantly higher for
Mo C+FAU (20 C-mol%) than for MoC /FAU (0.3 C-mol%).
. The product selectiv-
C
2
~C
5
light gas elements were not produced from hydro-
~C light gases are
2
x
genation/hydrocracking. Instead, C
2
5
The formation of alkylated aromatics can clearly be at-
tributed to the transalkylation of methoxy groups from one
anisole molecule to another by the Brønsted acid sites. The
prompt deoxygenation of the alkylated anisole species is
enabled by the molybdenum carbide species in close vicin-
likely formed from C-C coupling reactions of anisole-
derived methanol intermediates via methanol-to-olefin
pathways at the zeolite acid sites.
ity of the Brønsted acid sites for MoC
x
/FAU, whereas this is
not the case for Mo C+FAU, which has a significantly longer
2
physical distance between the two sites, allowing the de-
sorption of these intermediate species before the subse-
quent deoxygenation step. It should be noted that the bind-
ing energy of C-O bond in anisole was reported to be lower
3
1
in comparison to that of C-O bond in phenol , and we hy-
pothesize that this difference is likely the key factor for the
selective deoxygenation of the (alkylated) anisole inter-
mediate species by MoC /FAU compared to phenols.
x
Figure 5. A) Final product selectivity (TOS = 1200 min)
among the light gas C5- products (Conversion = 97% for
MoC
results for aliphatic carbon/benzene ring molar balance
throughout the reaction run for MoC /FAU. Reaction condi-
x
/FAU; Conversion = 49% for Mo
2
C), and B) Calculated
Figure 4. Reaction selectivity of MoC
parent FAU, and Mo C+FAU catalysts at the final point of
reaction run (TOS = 1200 min). The conversions of these
catalysts were 97% (MoC /FAU), 49% (Mo C), 31% (FAU),
and 61% (Mo C+FAU). Reaction conditions are identical to
x
/FAU, pristine Mo C,
2
x
2
tions identical to those described in Figure 3.
x
2
2
The fate of methoxy groups during the reaction with
those described in Figure 2. Aromatics C8+ include
ethylbenzene, xylenes and the other deoxygenated aromat-
ics having more than eight carbons. Alkylated phenols in-
clude phenolic compounds with more than seven carbon
atoms such as cresols. Alkylated anisoles include substitut-
ed anisoles with more than eight carbon atoms such as
methyl anisole. Light gas C5- includes aliphatic hydrocar-
bons with carbon numbers between one and five such as
methane and ethane.
MoC
routes, namely: 1) hydrodeoxygenation (benzene ring-
oxygen bonding cleavage) by MoC nanoclusters followed
x
/FAU catalysts should result in two distinct reaction
x
by alkylation of the intermediate methanol groups to the
aromatics; and 2) transalkylation of methoxy group to the
aromatics followed by the deoxygenation of the phenolic
hydroxy group. To realize such tandem reaction mecha-
nism, the presence of both selective deoxygenation sites by
molybdenum carbide nanoclusters, as well as the strong
Brønsted acidity of zeolites are required.
Nanocluster agglomeration in MoC /FAU during the re-
x
Remarkably, when using the bifunctional MoC
terials, methane formation was severely hindered (0.2 C-
mol% in selectivity), while C ~C hydrocarbons (~2.6 C-
mol% selectivity in total) was confirmed inside the light
x
/FAU ma-
action was ruled out from TEM images showing similar
particle sizes as those observed before reaction (Figure
S12). Also, the deactivaton of MoCx/FAU was investigated
2
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with an experiment using a reduced catalyst loading (1/3
The High Energy Total X-ray Scattering experiments conduct-
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ed at SPring-8 were approved by the Japan Synchrotron Radi-
ation Research Institute (Proposal Nos. 2015B0115 and
2016A0115). T. I. thanks the Japan Society for the Promotion
of Science for a Grant-in-aid for Scientific research, and the
Program for Leading Graduate Schools, “Global Leader Pro-
gram for Social Design and Management (GSDM)”, by the Min-
istry of Education, Culture, Sports, Science and Technology, for
the financial support. This work was supported by the U.S.
Department of Energy, Office of Basic Energy Sciences under
Award No. DE-SC0016214.
of the original loading) to operate at conversion values
under 100% (Figure S13). At these conditions, this catalyst
featured two deactivation profiles: one during the transi-
ent period (TOS < 400 min), followed by a more gradual
one thereafter. Notably, the catalyst was fully regenerated
by a hydrogen treatment at 500°C for 4 h, thus confirming
that catalyst deactivation was reversible and also ruling
out nanocluster sintering. TGA measurements revealed the
presence of 8.6 wt% of carbon deposits relative to the cata-
lyst mass, pointing at coking as a possible deactivation
mode. Although XPS does not show that bulk oxidation of
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REFERENCES
the MoC nanoclusters occurred even after exposure to air,
x
(
1)
Jiao, F.; Li, J. J.; Pan, X. L.; Xiao, J. P.; Li, H. B.; Ma, H.; Wei,
we cannot rule out the formation of an oxycarbide layer
during reaction.
M. M.; Pan, Y.; Zhou, Z. Y.; Li, M. R.; Miao, S.; Li, J.; Zhu, Y. F.; Xiao,
D.; He, T.; Yang, J. H.; Qi, F.; Fu, Q.; Bao, X. H. Science 2016, 351,
1065–1068.
In summary, d-PDF analyses confirmed that MoC /FAU
x
catalysts comprising molybdenum carbide nanoclusters
with ~1 nm diameter were successfully encapsulated with-
in the pores of FAU zeolite with high uniformity. This ma-
terial was shown to be an efficient catalyst for the produc-
tion of alkylated aromatics (alkylation ratio: 2.9) from ani-
sole, while preventing the formation of methane byprod-
(2)
Sartipi, S.; Makkee, M.; Kapteijn, F.; Gascon, J. Catal. Sci.
Technol. 2014, 4, 893–907.
(
(
(
3)
4)
5)
Guisnet, M. Catal. Today 2013, 218–219, 123–134.
Levy, R. B.; Boudart, M. Science 1973, 181, 547–549.
Esposito, D. V; Hunt, S. T.; Kimmel, Y. C.; Chen, J. G. G. J.
Am. Chem. Soc. 2012, 134, 3025–3033.
6) Hunt, S. T.; Milina, M.; Alba-Rubio, A. C.; Hendon, C. H.;
Dumesic, J. A.; Roman-Leshkov, Y. Science 2016, 352, 974–978.
7) Xiong, K.; Yu, W.; Vlachos, D. G.; Chen, J. G. ChemCatChem
2015, 7, 1402–1421.
(
ucts (0.2 C-mol%) in comparison to the pristine Mo C cata-
2
lyst (12 C-mol%). From the control experiments, the close
proximity of the Brønsted acid sites around the metallic
sites was suggested to be the key factor for enabling such
reaction selectivity values and for increasing on-stream
stability. The current findings not only suggest the exist-
ence of important advantages from having transition metal
carbide nanoclusters inside zeolite structure for catalytic
applications in HDO processes, but also open up new ave-
nues for other chemical reactions that can make good use
of bifunctionality of the metallic sites and zeolitic Brønsted
acid sites.
(
(8)
Sullivan, M. M.; Chen, C. J.; Bhan, A. Catal. Sci. Technol.
2016, 6, 602–616.
(9)
Santos, V. P.; Wezendonk, T. A.; Jaen, J. J. D.; Dugulan, A.
I.; Nasalevich, M. A.; Islam, H. U.; Chojecki, A.; Sartipi, S.; Sun, X.;
Hakeem, A. A.; Koeken, A. C. J.; Ruitenbeek, M.; Davidian, T.; Mei-
ma, G. R.; Sankar, G.; Kapteijn, F.; Makkee, M.; Gascon, J. Nat. Com-
mun. 2015, 6, 6451.
(
10) Zhong, L. S.; Yu, F.; An, Y. L.; Zhao, Y. H.; Sun, Y. H.; Li, Z.
J.; Lin, T. J.; Lin, Y. J.; Qi, X. Z.; Dai, Y. Y.; Gu, L.; Hu, J. S.; Jin, S. F.;
Shen, Q.; Wang, H. Nature 2016, 538, 84–87.
(
11) Borry, R. W.; Kim, Y. H.; Huffsmith, A.; Reimer, J. A.; Igle-
sia, E. J. Phys. Chem. B 1999, 103, 5787–5796.
12) Li, W.; Meitzner, G. D.; Borry, R. W.; Iglesia, E. J. Catal.
000, 191, 373–383.
13) Kosinov, N.; Coumans, F. J. A. G.; Uslamin, E. A.; Wijp-
ASSOCIATED CONTENT
(
Supporting Information. PXRD patterns, further d-PDF anal-
ysis results, XPS spectra, BET specific surface areas, micropore
volumes, Ziman-Faber total structure factor, S(Q), used for
calculating the pair distribution functions, G(r), selectivity
time profile of various catalysts, evaluation of external and
internal mass transfer, TEM image of catalyst after reaction.
This material is available free of charge on the Internet at
http://pubs.acs.org.
2
(
kema, A. S. G.; Mezari, B.; Hensen, E. J. M. ACS Catal. 2017, 7, 520–
529.
(14) Farrusseng, D.; Tuel, A. New J. Chem. 2016, 40, 3933–
3949.
(15) Alexeev, O.; Gates, B. C. Top. Catal. 2000, 10, 273–293.
(16) Hammer, B.; Morikawa, Y.; Norskov, J. K. Phys. Rev. Lett.
996, 76, 2141–2144.
1
(17) Lee, W.; Kumar, A.; Wang, Z.; Bhan, A. ACS Catal. 2015,
5, 4104–4114.
AUTHOR INFORMATION
Corresponding Author
(
(
18) Oyama, S. T. Catal. Today 1992, 15, 179–200.
19) Gao, J.; Zheng, Y.; Fitzgerald, G. B.; de Joannis, J.; Tang, Y.;
*wakihara@chemsys.t.u-tokyo.ac.jp
Wachs, I. E.; Podkolzin, S. G. J. Phys. Chem. C 2014, 118, 4670–
679.
20) Proffen, T.; Billinge, S. J. L.; Egami, T.; Louca, D.
*yroman@mit.edu
4
(
Zeitschrift für Krist. 2003, 218, 132–143.
(21) Billinge, S. J.; Kanatzidis, M. G. Chem. Commun. 2004,
749–760.
(22) Chupas, P. J.; Chapman, K. W.; Chen, H. L.; Grey, C. P.
Catal. Today 2009, 145, 213–219.
(23) Petkov, V.; Jeong, I.-K.; Chung, J. S.; Thorpe, M. F.; Kycia,
S.; Billinge, S. J. L. Phys. Rev. Lett. 1999, 83, 4089–4092.
(24) Zakzeski, J.; Bruijnincx, P. C. A.; Jongerius, A. L.; Weck-
huysen, B. M. Chem. Rev. 2010, 110, 3552–3599.
Present Addresses
†
If an author’s address is different than the one given in the
affiliation line, this information may be included here.
Author Contributions
The manuscript was written through contributions of all au-
thors.
(
25) Lee, W. S.; Wang, Z.; Wu, R. J.; Bhan, A. J. Catal. 2014,
ACKNOWLEDGMENT
3
19, 44–53.
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Page 6 of 7
(
26) Jae, J.; Tompsett, G. A.; Foster, A. J.; Hammond, K. D.; Au-
erbach, S. M.; Lobo, R. F.; Huber, G. W. J. Catal. 2011, 279, 257–
68.
27) Chapman, K. W.; Chupas, P. J.; Kepert, C. J. J. Am. Chem.
Soc. 2005, 127, 11232–11233.
28) Farrow, C. L.; Juhas, P.; Liu, J. W.; Bryndin, D.; Božin, E.
(30) Foo, G. S.; Rogers, A. K.; Yung, M. M.; Sievers, C. ACS
Catal. 2016, 6, 1292–1307.
(31) Prasomsri, T.; Shetty, M.; Murugappan, K.; Román-
Leshkov, Y. Energy Environ. Sci. 2014, 7, 2660–2669.
(32) Anderson, E.; Crisci, A.; Murugappan, K.; Roman-
Leshkov, Y. ChemSusChem 2017, 10, 2226–2234.
1
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2
(
(
S.; Bloch, J.; Proffen, T.; Billinge, S. J. L. J. Phys. Condens. Matter
2007, 19, 335219.
(29) Zhu, X. L.; Lobban, L. L.; Mallinson, R. G.; Resasco, D. E. J.
Catal. 2011, 281, 21–29.
(33) Shetty, M.; Murugappan, K.; Green, W. H.; Roman-
Leshkov, Y. ACS Sustain. Chem. Eng. 2017, 5, 5293–5301.
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