Discovering positively charged Pt for enhanced hydrogenolysis of glycerol to 1,3-propanediol

Article abstract of DOI:10.1039/d0gc03364b

Atomically-dispersed Pt supported on WOx-modified tantalum oxide was developed as a highly active catalyst for selective hydrogenolysis of glycerol, with the productivity of 30.80 g gPt-1 h-1 toward 1,3-propanediol. The WOx species pre-deposited on T-Ta2O5 were found to assist the atomic dispersion of platinum. The WOx-stabilized Ptδ+ species adsorb hydrogen easily and facilitate the hydrogen heterolytic dissociation, which significantly enhances the capability of in situ generated Br?nsted acid sites and the hydrogenation activity. This provides a new strategy for developing bi-functional catalysts for a broad range of hydrogen and acid-involved reaction.

Full text of DOI:10.1039/d0gc03364b

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Discovering positively charged Pt for enhanced
hydrogenolysis of glycerol to 1,3-propanediol†
Cite this: DOI: 10.1039/d0gc03364b
a,c
Binbin Zhao,a Yu Liang,a Lei Liu, *a Qian He *b and Jinxiang Dong
Received 6th October 2020,
Accepted 16th November 2020
DOI: 10.1039/d0gc03364b
rsc.li/greenchem
Atomically-dispersed Pt supported on WOx-modified tantalum atomic utilization efficiency and unsatisfying catalytic
oxide was developed as a highly active catalyst for selective hydro- results.8,11,16–18 Therefore, improving the platinum and WOx
−1
genolysis of glycerol, with the productivity of 30.80 g gPt h−1 dispersion and further optimize their interaction promises
toward 1,3-propanediol. The WOx species pre-deposited on further enhancements for the overall catalytic performance.
T-Ta2O5 were found to assist the atomic dispersion of platinum.
It is now widely accepted that glycerol hydrogenolysis to
The WOx-stabilized Ptδ+ species adsorb hydrogen easily and facili- 1,3-PDO over bi-functional catalysts proceeds through dehydra-
tate the hydrogen heterolytic dissociation, which significantly tion of glycerol to 3-hydroxypropanal (3-HPA) over Brønsted
enhances the capability of in situ generated Brønsted acid sites acidic sites followed by consecutive hydrogenation over Pt
and the hydrogenation activity. This provides a new strategy for metal nanoparticles.19–26 The intermediate of 3-HPA is very
developing bi-functional catalysts for a broad range of hydrogen unstable and fast hydrogenation of 3-HPA is very crucial to
and acid-involved reaction.
achieve a high selectivity toward 1,3-PDO.27
Recently, atomically dispersed platinum catalysts as hydro-
genation active sites were widely studied, showing high activity
and selectivity for the hydrogenation of substrates containing
polar functional groups.28–30 For example, Yan et al. reported a
stable Pt single-atom catalyst using phosphomolybdic acid-
modified active carbon as support, in which the positively
charged Pt could adsorb hydrogen easily, showing a high
hydrogenation activity in the case of the substrate containing
–CvO group.29 Inspired by this, we prepared a positively
charged single/pseudo-single atom Pt catalyst on WOx-modi-
fied tantalum oxide, achieving high productivity of 1,3-PDO
The boom in the biodiesel industry brings about a significant
amount of surplus glycerol, thus converting glycerol into
value-added chemicals is of great importance to the sustain-
ability of global biodiesel production.1 Converting glycerol to
1,3-propanediol (1,3-PDO), an important monomer for produ-
cing polytrimethylene terephthalate, is an attractive approach
that could reduce our dependence on fossil feedstock.2,3
Among many recent works on searching for suitable
catalysts,4–13 supported Pt and WOx catalysts show high com-
mercialization potential due to their superior catalytic per-
formance and high stability. Normally, high loadings of tung-
(30.80 g gPt h−1) for glycerol hydrogenolysis. Such high cata-
−1
sten (e.g. 10 wt%) and platinum (e.g. 2 wt%) are required to
lytic performance was attributed to both the high dispersion
of Pt and an optimized interface between Pt and WOx species.
The crystalline T-phase Ta2O5 (T-Ta2O5) was prepared from
hydrated oxide (Ta2O5·nH2O) by calcination at 900 °C,31 and
was chosen as support owing to its outstanding thermal and
hydrothermal stability, and the high similarity with W-species
in electronegativity and ionic radius which would be helpful to
enhance the dispersion of WOx species on its surface.32
Especially, the negligible acidic property for T-Ta2O5 could
minimize glycerol dehydration on the support, and allow us to
investigate the reaction mechanism over the Pt and WOx-based
catalysts. T-Ta2O5 with nano-scale size (∼200 nm) was prepared
using a solvothermal method followed by calcination at 900 °C
(ESI†). To ensure the high dispersion of WOx on the T-Ta2O5
surface, a simple impregnation–centrifugation method has
−1
achieve the desired productivity of 1,3-PDO (15.2 g gPt h−1
,
Table S1†). The active sites are thought to be the interface
between the Pt and WOx species, which are optimized to a
certain extent by increasing their loadings.11,14,15 However,
such high loading of Pt and W often results in inactive highly
polymerized WOx species or large particles, leading to a low
aCollege of Chemistry and Chemical Engineering, Taiyuan University of Technology,
Taiyuan, Shanxi 030024, P. R. China. E-mail: liulei@tyut.edu.cn
bDepartment of Materials Science and Engineering, National University of Singapore,
Singapore 117575. E-mail: heqian@nus.edu.sg
cSchool of Chemical Engineering and Light Industry, Guangdong University of
Technology, Guangzhou 510006, P. R. China
†Electronic supplementary information (ESI) available. See DOI: 10.1039/
d0gc03364b
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been developed to load the WOx species. Platinum was further (HAADF) Z-contrast STEM images of the Ptδ+/WOx/T-Ta2O5
dispersed onto the WOx/T-Ta2O5 with a second impregnation catalyst are shown in Fig. 1(a and b). Ultra-small (e.g. 1 nm or
step (denoted as Ptδ+/WOx/T-Ta2O5). The essential physico- less) species can be found on the T-Ta2O5 support. The small
chemical properties of T-Ta2O5 before and after loading W and size and similarity of the atomic number of Ta (Z = 73),
Pt were summarized in Table S2,† wherein the actual loading W (Z = 74) and Pt (Z = 78) made it difficult to directly differen-
of W and Pt was determined by ICP-AES method, with tiate these elements.9 Therefore, two additional samples were
0.68 wt% for Pt and 0.51 wt% for W in a typical Ptδ+/WOx/ studied for comparison, namely WOx/T-Ta2O5 and Pt/T-Ta2O5.
T-Ta2O5 catalyst, respectively (Scheme 1).
WOx clusters can be found in the WOx/T-Ta2O5 (Fig. 1(c and
The structure of T-Ta2O5 remains unchanged after loading d)) which are very similar in size compared to the ones in the
WOx and platinum species, as evidenced by powder XRD pat- Ptδ+/WOx/T-Ta2O5 catalyst. And Pt nanoparticles can be
terns (Fig. S1†). The absence of Pt and WO3 nanoparticles clearly seen from the Pt/T-Ta2O5 sample (Fig. 1(e and f)).
diffraction peaks revealed the homogeneous dispersion of Pt From these comparisons, it is reasonable to speculate that Pt
metal and low polymerized tungsten oxide species on the dispersion has been significantly improved due to the pres-
support surface.17,25,33
ence of WOx species deposited priority on the support, acting
Raman and UV-vis characterization was also used to as anchoring sites. Since no obvious size increase was
identify the dispersion and the polymerization degree of observed in those clusters shown in Fig. 1(a) compared to
WOx species. For WOx/T-Ta2O5 and Ptδ+/WOx/T-Ta2O5 samples, Fig. 1(c), it can be inferred that no Pt nanoparticles were
Raman spectra (Fig. S2†) show there is no typical characteristic formed onto WOx and Pt is likely to be atomically dispersed
peaks for crystalline WO3 (805 cm−1 for W–O stretching, on the entire WOx/T-Ta2O5 surface.
270 cm−1 for W–O–W deformation).17,18 And only the band at
Probe molecule infrared (IR) spectroscopy with CO has
950–1000 cm−1 corresponding to the stretching mode of WvO been widely used to identify the valence state and dispersion
in the highly dispersed WOx species was observed.34–36 The for Pt species on the catalyst. Because the adsorbed CO could
absorption edge of WOx/T-Ta2O5 in UV-vis spectra move to a not be detected on the bare WOx/T-Ta2O5, the peaks upon
higher wavelength of 315 nm compared with pristine T-Ta2O5 loading Pt were derived from the CO adsorbed on different Pt
(Fig. S3†), confirming that no high polymerized WOx species species (Fig. 2a). Two dominant peaks at 2138 cm−1 and
were formed on the T-Ta2O5 surface.37,38 And the band cen- 2091 cm−1 for Ptδ+/WOx/T-Ta2O5 were ascribed to the linearly
tered around 225nm-260 nm is attributed to isolated tungsten bonded CO on isolated Ptδ+ species and PtOx clusters (<1 nm),
species or low polymeric tungsten oxide species in a distorted
tetrahedral or an octahedral coordination environment,39 the
similar results were also observed on the W/SiO2, and further
confirmed by X-ray absorption spectroscopy study.40 From
these results, it can be seen that the developed impregnation–
centrifugation method is a powerful strategy to achieve highly-
dispersed WOx species with a low polymeric state on T-Ta2O5
surface, which was suggested to be the actual active com-
ponents combining with Pt species for glycerol hydrogenolysis
to 1,3-PDO.8,11,14
SEM images show that Ptδ+/WOx/T-Ta2O5 has a coral-
shaped morphology with a particle size of 100–200 nm
(Fig. S4†). The dispersion of Pt and WOx were further investi-
gated using aberration-corrected scanning transmission
electron microscopy (STEM). High angle annular dark-field
Fig. 1 STEM-HAADF images of (a and b) Ptδ+/WOx/T-Ta2O5 catalyst, (c
and d) WOx/T-Ta2O5 catalyst and (e and f) Pt/T-Ta2O5 catalyst.
Scheme 1 Illustration of preparation process of Ptδ+/WOx/T-Ta2O5.
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species between those of Pt(II) and Pt(IV) were detected in Ptδ+/
WOx/T-Ta2O5 catalysts. It should be noted that the Pt 4f bands
shift to the higher binding energies (Pt 4f5/2 72.98 eV and Pt
4f7/2 76.36 eV) after depositing WOx species on the support,
indicating the strong interaction between the Pt and WOx
species behaved on the support surface. According to H2-TPR
test results (Fig. S5†), the main reduction peaks of Ptδ+ species
on Ptδ+/WOx/T-Ta2O5 occurs at 545 °C that is higher than that
of WOx-free catalysts, while the H2 consumed for reduction of
Ptδ+ species is greater than that observed on Ptδ+/T-Ta2O5 with
the same Pt content, indicating that the strong metal–support
interaction (SMSI) between Pt and WOx/T-Ta2O5 as well as a
more high-dispersion of Pt species on WOx/T-Ta2O5. Based on
TEM, IR, XPS, and H2-TPR results, we can conclude that the
isolated Ptδ+ species and platinum oxide clusters were highly
dispersed on the surface of the support, and the SMSI between
Pt and WOx assure the Ptδ+ species to disperse at the atomic-
level.9,49
Fig. 2 IR spectra of CO adsorbed on various catalysts during desorp-
tion processes, and XPS spectra of Pt 4f: Ptδ+/WOx/T-Ta2O5 (a and c),
Pt/T-Ta2O5 (b and d).
The catalytic properties in the glycerol hydrogenolysis were
shown in Table 1. It can be seen that Ptδ+/WOx/T-Ta2O5 catalyst
respectively.41–45 For Pt supported catalysts, the peak position exhibits significantly high catalytic activity and selectivity
for the adsorbed CO molecules are closely associated with the toward 1,3-PDO (1,3-PDO/1,2-PDO molar ratio = 68.61) com-
electronic structure of Pt species and the bonding configur- pared to the pristine T-Ta2O5 supported Pt catalyst. Moreover,
ation of the Pt to CO.46,47 The bonding energy of Pt species in the catalytic results of glycerol hydrogenolysis over Ptδ+/WOx/
Pt/T-Ta2O5 is less than that of Ptδ+/WOx/T-Ta2O5, as confirmed T-Ta2O5 (Table S3†) during the reaction process indicated that
by X-ray photoelectron spectroscopy (Fig. 2), as a result, the the selectivity of 1,3-PDO was stable, showing excellent per-
peak corresponding to CO adsorbed on isolated Ptδ+ species formance for the selective cleavage of the second C–O bond of
was red shifted to 2124 cm−1 from 2138 cm−1 for Pt/T-Ta2O5. glycerol. The nature and the number of acidic sites on catalysts
The peaks at 2078 cm−1 and 1830 cm−1 are assigned to the lin- are also very important to glycerol hydrogenolysis. The NH3-
early bonded CO on Pt nanoparticles and the bridge-bonded TPD and FTIR of adsorbed pyridine over catalysts were per-
CO on Pt nanoparticles in more large size, respectively, while formed to reveal the acidic property (Fig. S6 and S7†), however,
the latter is not observed on Ptδ+/WOx/T-Ta2O5.41,42,48 Also, the only the weak Lewis acid sites in Py-IR spectra were observed
peak intensity corresponding to the isolated Ptδ+ species in on Ptδ+/WOx/T-Ta2O5, which is associated with the presence of
Ptδ+/WOx/T-Ta2O5 is much higher than that of Pt/T-Ta2O5, terminal WvO group upon loading WOx species on T-Ta2O5.
showing that much more isolated Pt species were formed on Generally, Brønsted acid sites play a crucial role to achieve a
WOx/T-Ta2O5. The Pt species could be well held in a highly dis- high selectivity toward 1,3-PDO in glycerol hydrogenolysis over
persed state by their strong interaction with WOx islands bi-functional catalysts.5,8,17 To confirm if the protonic acid site
formed on the T-Ta2O5 surface.
could be in situ generated on Ptδ+/WOx/T-Ta2O5 catalyst during
The electronic state of the two supported Pt catalysts were the glycerol hydrogenolysis, the control Py-IR experiment was
further investigated with X-ray photoelectron spectroscopy conducted by co-feeding H2 with pyridine. Interestingly, we
(XPS). XPS spectra (Fig. 2c) show that only cationic platinum observed a new peak at 1540 cm−1 corresponding to the pyri-
Table 1 Catalytic results of glycerol hydrogenolysis over various catalysts in aqueous mediaa
Selectivity (%)
Selectivity ratio
Entry
Catalyst
Time (h)
Conversion (%)
1,3-PDO
1,2-PDO
2-PrOH
1-PrOH
(1,3/1,2)
1
2
3
4
5
WOx/T-Ta2O5
Pt/T-Ta2O5
12
12
12
12
12
24
—
3.77
89.88
22.71
53.71
87.00
—
—
—
—
—
0.34
68.61
14.53
30.88
63.96
7.24
44.8
54.35
49.41
45.61
21.02
0.65
3.74
1.60
0.76
5.83
4.42
5.18
5.58
4.15
60.93
42.36
30.92
35.50
38.56
Ptδ+/WOx/T-Ta2O5
Pt0/WOx/T-Ta2O5
b
Ptδ+/WOx/T-Ta2O5
b
a Reaction conditions: 6.184 g of 3 wt% glycerol solution, 0.2 g of catalyst, 160 °C, 5.0 MPa H2 pressure, stirring rate of 600 rpm. 1-PrOH, 2-PrOH,
and 1,2-PDO refer to 1-propanol, 2-propanol, and 1,2-propanediol, respectively. b 30 wt% glycerol solution was applied under identical reaction
condition.
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dine on Brønsted acid sites (Fig. S8†), indicating that the that Ptδ+/WOx/T-Ta2O5 has potential in successive hydration–
Brønsted acid sites could be available for the first-step de- hydrogenation reaction.
hydration of glycerol by H2 dissociation over the interface of Pt
It has been recognized that fast hydrogenation of 3-HPA
and WOx during the reaction. Hydrogen activation is signifi- over Pt is a key step for the formation of 1,3-PDO from glycerol
cantly important for the selective hydrogenolysis of glycerol to hydrogenolysis.22,23 Since 3-HPA is not stable and not commer-
1,3-PDO, which is associated with the in situ Brønsted acid cially available, we attempted to use propanal as a model mole-
generation for dehydration and the activated H-species for cular to evaluate the hydrogenation activity of the carbonyl
hydrogenation.9,10,12 The activation mode of H2 on atomically group on various Pt containing catalysts. Ptδ+/WOx/T-Ta2O5
dispersed metal species is closely related to the local coordi- catalyst exhibited much higher activity than that of the
nation environment, the hydrogen heterolytic dissociation is reduced catalyst of Pt0/WOx/T-Ta2O5 in the hydrogenation of
more favored on positively charged single atoms than that on propanal to 1-PrOH (Fig. 3d) at room temperature. Based on
metallic atoms.30 The positively charged Pt species in Ptδ+/ this fact, we infer that the positively charged Pt species in
WOx/T-Ta2O5 enable H2 to heterolytically dissociate to Hδ+ and atomic-level dispersion are ideal active sites compared with
Hδ− species, and Hδ+ species spilled over the surface of metal Pt for the fast hydrogenation of 3-HPA intermediate to
support via Pt–O–W interfacial, forming O–Hδ+ and Pt–Hδ− 1,3-PDO, further illustrating the applied potential of the posi-
species.9,50 A control experiment was conducted on Pt0/WOx/ tively charged single metal atoms in hydrogen-involved
T-Ta2O5 catalyst obtained from Ptδ+/WOx/T-Ta2O5 by H2 reaction.29
reduction treatment, in which the Pt species mainly existed in
Combining the current characterization and catalytic reac-
the form of Pt0, as evidenced by XPS (Fig. S9†). The catalytic tion results, a plausible reaction scheme was proposed for gly-
results (Table 1, entry 4) show the glycerol conversion on Ptδ+ cerol hydrogenolysis on the studied catalyst (Scheme 2). First,
catalyst is about 2.5 times higher than that on Pt0 catalyst, hydrogen was absorbed and heterolytically dissociated to Hδ+
indicating that the high catalytic activity is attributed to the and Hδ− species over the positively charged Pt single atoms,
Ptδ+–O–W species.51
and Hδ+ species could spillover from Pt atoms to the support
H2–O2 titration experiment was carried out to investigate via Pt–O–W interfacial leading to the generation of W–(OH)–Ta
the hydrogen absorption performance of Pt-based catalysts. species as Brønsted acid sites.12,52,53 The primary –OH group
The H2 consumption was not detected on WOx/T-Ta2O5 of glycerol molecular was inclined to chemisorb on the cat-
(Fig. S10†) and consequently, any H2 uptake is attributed to ionic Pt cluster owing to the high charge density. The in situ
the presence of Pt species on support. Control experiments generations of Brønsted acid sites are favorable for eliminating
demonstrate that Ptδ+/WOx/T-Ta2O5 exhibits a significantly the secondary –OH group to form a secondary carbenium,
high H2 adsorption capacity compared to the two other cata- then 3-HPA by keto–enol tautomerism. The high activity of Ptδ+
lysts with the same Pt loading (Fig. 3). The excellent H2 absorp- species assured the speedy hydrogenation of 3-HPA to 1,3-
tion capability was attributed to the atomically dispersed plati- PDO.
num species, as well as the maximized interface between Pt
The reusability and stability of Ptδ+/WOx/T-Ta2O5 were firstly
and WOx which facilitates the dissociated H-species spillover investigated with four successive runs under the regular reac-
and form the Brønsted acid sites on the catalyst,9 implying tion condition (Table 1, entry 3). After each reaction run, the
catalyst was recovered, washed with distilled water and dried at
110 °C temperature before the next reaction. As shown in
Fig. 3 H2–O2 titration profiles Ptδ+/WOx/T-Ta2O5 (a), Pt/T-Ta2O5 (b),
Ptδ+/WOx/T-Ta2O5 (c) and the catalytic results (d) of propanal hydrogen-
ation over various Pt-containing catalysts.
Scheme 2 Proposed reaction mechanism of glycerol hydrogenolysis to
1,3-PDO over Ptδ+/WOx/T-Ta2O5.
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productivity of 1,3-PDO in the hydrogenolysis of glycerol,
which is much higher than the reported results so far with Pt-
WOx-based catalysts. The superior catalytic performance was
attributed to the highly-dispersed Ptδ+ and the strong inter-
action between Pt and WOx/T-Ta2O5, which facilitates the
hydrogen heterolytic dissociation and H-species spillover to
produce Brønsted acid sites, and affords a high catalytic
activity for hydrogenation. This discovery will be helpful to
understand the glycerol hydrogenolysis mechanism, and also
provide an ideal in designing powerful bi-functional catalysts
for the hydrogen and acid-involved reaction.
Conflicts of interest
There are no conflicts to declare.
Fig. 4 The conversion and product distribution in glycerol hydrogeno-
lysis over the Ptδ+/WOx/T-Ta2O5 catalyst in four successive runs.
Acknowledgements
Fig. 4, the conversion rate of glycerol showed a small decrease
from 89.88% to 78.56% after four successive runs, while the
selectivity toward 1,3-PDO kept stable at about 45%. It should
be noted that, the glycerol conversion dropped relatively
quickly (about 6%) after the first run, then very slowly in the
next successive runs. Elemental analysis for the reaction liquid
was done and no leaching of Pt or W from the catalyst was
detected. XPS was used to identify the valence states of Pt-
species in the catalyst after the first and 4th run (Fig. S11†),
and the fitting results are summarized in Table S4.† It was
found that the surface Ptδ+/(Ptδ+ + Pt0) ratio in catalyst rapidly
decreased to about 55% from 100% after the first run,
however, the further reduction of Ptδ+ species had not been
obviously observed in the next runs, and there is still more
than 44% Ptδ+ species remained on the catalyst even after the
4th run. Therefore, the obvious drop in activity for the 2nd run
probably resulted from the reduction of a portion of Ptδ+
species during the reaction, and this easily reducible Ptδ+
species could be ascribed to their weak interaction with WOx.
By contrast, the Ptδ+ species having strong interaction with
WOx could be well kept during reaction owing to its high
reduction temperature as confirmed by H2-TPR results
(Fig. S5†), which showed much higher catalytic activity com-
pared to the easily reducible ones. Consequently, the catalytic
activity for Ptδ+/WOx/T-Ta2O5 could remain at a high level in
the next successive runs. Moreover, only one peak corres-
ponding PtOx clusters (<1 nm) was detected in the IR spectra
of CO adsorbed on the used catalyst (Fig. S12†), indicating
that high dispersed WOx could enhance the stability of plati-
num species and effectively inhibit their agglomeration during
the reaction. These results certify that Ptδ+/WOx/T-Ta2O5 cata-
lyst has an operational reusability and remarkable stability in
our current reaction condition for the hydrogenolysis of gly-
cerol, and potential in a candidate for practical application.
In conclusion, we prepared a stable positively charged Pt
catalyst with atomic-level dispersion by loading an extremely
low content of WOx species on T-Ta2O5, exhibiting remarkable
This work was financially supported by the National Natural
Science Foundation (21978194 and U1910202), the Natural
Science Foundation of Shanxi Province (Grant No.
201801D121055), and Program for the Shanxi Young Sanjin
Scholar. Qian He would like to acknowledge the support by
National Research Foundation (NRF) Singapore, under its NRF
Fellowship (NRF-NRFF11-2019-0002).
Notes and references
1 M. Pagliaro, R. Ciriminna, H. Kimura, M. Rossi and
C. D. Pina, Angew. Chem., Int. Ed., 2007, 46, 4434–4440.
2 A. M. Ruppert, K. Weinberg and R. Palkovits, Angew. Chem.,
Int. Ed., 2012, 51, 2564–2601.
3 U. Witt, R.-J. Müller, J. Augusta, H. Widdecke and
W.-D. Deckwer, Macromol. Chem. Phys., 1994, 195, 793–802.
4 L. Z. Qin, M. J. Song and C. L. Chen, Green Chem., 2010, 12,
1466–1472.
5 S. Zhu, X. Gao, Y. Zhu, Y. Zhu, X. Xiang, C. Hu and Y. Li,
Appl. Catal., B, 2013, 140–141, 60–67.
6 R. Arundhathi, T. Mizugaki, T. Mitsudome, K. Jitsukawa
and K. Kaneda, ChemSusChem, 2013, 6, 1345–1347.
7 D. D. Falcone, J. H. Hack, A. Y. Klyushin, A. Knop-Gericke,
R. Schlögl and R. J. Davis, ACS Catal., 2015, 5, 5679–5695.
8 S.
García-fernández,
I.
Gandarias,
J.
Requies,
M. B. Güemez, S. Bennici, A. Auroux and P. L. Arias,
J. Catal., 2015, 323, 65–75.
9 J. Wang, X. Zhao, N. Lei, L. Li, L. Zhang and S. Xu,
ChemSusChem, 2016, 9, 784–790.
10 Y. Fan, S. Cheng, H. Wang, D. Ye, S. Xie, Y. Pei, H. Hu,
W. Hua, Z. H. Li, M. Qiao and B. Zong, Green Chem., 2017,
19, 2174–2183.
11 W. Zhou, J. Luo, Y. Wang, J. Liu, Y. Zhao, S. Wang and
X. Ma, Appl. Catal., B, 2019, 242, 410–421.
12 T. Aihara, H. Miura and T. Shishido, Catal. Sci. Technol.,
2019, 9, 5359–5367.
This journal is © The Royal Society of Chemistry 2020
Green Chem.

View Article Online
Communication
Green Chemistry
13 W. Zhou, Y. Zhao, Y. Wang, S. Wang and X. Ma, 34 T. Tsuchiya, H. Imai, S. Miyoshi, P. A. Glans, J. Guo and
ChemCatChem, 2016, 8, 3663–3671.
14 N. Lei, X. Zhao, B. Hou, M. Yang, M. Zhou, F. Liu, A. Wang
and T. Zhang, ChemCatChem, 2019, 11, 3903–3912.
S. Yamaguchi, Phys. Chem. Chem. Phys., 2011, 13, 17013–
17018.
35 Y. Chen and I. E. Wachs, J. Catal., 2003, 217, 468–477.
15 S. García-Fernández, I. Gandarias, Y. Tejido-Núñez, J. Requies 36 U. Balachandran and N. G. Eror, J. Mater. Sci. Lett., 1982, 1,
and P. L. Arias, ChemCatChem, 2017, 9, 4508–4519. 219–222.
16 Y. Fan, S. Cheng, H. Wang, J. Tian, S. Xie, Y. Pei, M. Qiao 37 Q. Lin, K. Ichi Shimizu and A. Satsuma, Appl. Catal., A,
and B. Zong, Appl. Catal., B, 2017, 217, 331–341. 2009, 365, 55–61.
17 S. Zhu, X. Gao, Y. Zhu and Y. Li, J. Mol. Catal. A: Chem., 38 D. G. Barton, M. Shtein, R. D. Wilson, S. L. Soled and
2015, 398, 391–398. E. Iglesia, J. Phys. Chem. B, 1999, 103, 630–640.
18 S. García-Fernández, I. Gandarias, Y. Tejido-Núñez, 39 S. Maksasithorn, P. Praserthdam, K. Suriye and
J. Requies and P. L. Arias, ChemCatChem, 2017, 9, 4508–
4519.
D. P. Debecker, Microporous Mesoporous Mater., 2015, 213,
125–133.
19 J. Chaminand, L. A. Djakovitch, P. Gallezot, P. Marion, 40 C. Bisio, A. Gallo, R. Psaro, C. Tiozzo, M. Guidotti and
C. Pinel and C. Rosier, Green Chem., 2004, 6, 359–361. F. Carniato, Appl. Catal., A, 2019, 581, 133–142.
20 T. Miyazawa, Y. Kusunoki, K. Kunimori and K. Tomishige, 41 M. J. Kale and P. Christopher, ACS Catal., 2016, 6, 5599–
J. Catal., 2006, 240, 213–221. 5609.
21 E. Tsukuda, S. Sato, R. Takahashi and T. Sodesawa, Catal. 42 K. Ding, A. Gulec, A. M. Johnson, N. M. Schweitzer,
Commun., 2007, 8, 1349–1353.
22 T. Miyazawa, S. Koso, K. Kunimori and K. Tomishige, Appl.
Catal., A, 2007, 318, 244–251.
23 I. Gandarias, P. L. Arias, J. Requies, M. B. Güemez and
J. L. G. Fierro, Appl. Catal., B, 2010, 97, 248–256.
24 S. Zhu, Y. Qiu, Y. Zhu, S. Hao, H. Zheng and Y. Li, Catal.
Today, 2013, 212, 120–126.
25 S. Zhu, X. Gao, Y. Zhu, J. Cui, H. Zheng and Y. Li, Appl.
Catal., B, 2014, 158–159, 391–399.
G. D. Stucky, L. D. Marks and P. C. Stair, Science, 2015, 350,
189–192.
43 M. J. Kappers and J. H. van der Maas, Catal. Lett., 1991, 10,
365–373.
44 E. V. Ramos-Fernández, B. Samaranch, P. R. de la Piscina,
N. Homs, J. L. G. Fierro, F. Rodríguez-Reinoso and
A. Sepúlveda-Escribano, Appl. Catal., A, 2008, 349, 165–
169.
45 O. Pozdnyakova, D. Teschner, A. Wootsch, J. Kröhnert,
B. Steinhauer, H. Sauer, L. Toth, F. C. Jentoft, A. Knop-
Gericke, Z. Paál and R. Schlögl, J. Catal., 2006, 237, 1–16.
26 D. Coll, F. Delbecq, Y. Aray and P. Sautet, Phys. Chem.
Chem. Phys., 2011, 13, 1448–1456.
27 M. R. Nimlos, S. J. Blanksby, X. Qian, M. E. Himmel and 46 E. Ivanova, M. Mihaylov, F. Thibault-Starzyk, M. Daturi and
D. K. Johnson, J. Phys. Chem. A, 2006, 110, 6145–6156. K. Hadjiivanov, J. Mol. Catal. A: Chem., 2007, 274, 179–184.
28 H. Wei, X. Liu, A. Wang, L. Zhang, B. Qiao, X. Yang, 47 G. J. Kim, D. W. Kwon and S. C. Hong, J. Phys. Chem. C,
Y. Huang, S. Miao, J. Liu and T. Zhang, Nat. Commun.,
2014, 5, 1–8.
29 B. Zhang, H. Asakura, J. Zhang, J. Zhang, S. De and N. Yan,
Angew. Chem., Int. Ed., 2016, 55, 8319–8323.
2016, 120, 17996–18004.
48 B. Qiao, A. Wang, X. Yang, L. F. Allard, Z. Jiang, Y. Cui,
J. Liu, J. Li and T. Zhang, Nat. Chem., 2011, 3, 634–641.
49 O. S. Alexeev, G. W. Graham, M. Shelef and B. C. Gates,
J. Catal, 2000, 190, 157–172.
30 Y. Chen, S. Ji, W. Sun, W. Chen, J. Dong, J. Wen, J. Zhang,
Z. Li, L. Zheng, C. Chen, Q. Peng, D. Wang and Y. Li, J. Am. 50 L. Bai, X. Wang, Q. Chen, Y. Ye, H. Zheng, J. Guo, Y. Yin
Chem. Soc., 2018, 140, 7407–7410. and C. Gao, Angew. Chem., Int. Ed., 2016, 55, 15656–15661.
31 T. Kitano, S. Okazaki, T. Shishido, K. Teramura and 51 M. N. Taylor, W. Zhou, T. Garcia, B. Solsona, A. F. Carley,
T. Tanaka, Chem. Lett., 2011, 40, 1332–1334. C. J. Kiely and S. H. Taylor, J. Catal., 2012, 285, 103–114.
32 L. Xu, Y. Wang, X. Yang, X. Yu, Y. Guo and J. H. Clark, 52 T. Kitano, T. Hayashi, T. Uesaka, T. Shishido, K. Teramura
Green Chem., 2008, 10, 746–755. and T. Tanaka, ChemCatChem, 2014, 6, 2011–2020.
33 W. Zhang, J. Chen, A. I. Minett, G. F. Swiegers, C. O. Too 53 T. Murayama, N. Kuramata and W. Ueda, J. Catal., 2016,
and G. G. Wallace, Chem. Commun., 2010, 46, 4824–4826. 339, 143–152.
Green Chem.
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