Hollow carbon anchored highly dispersed Pd species for selective hydrogenation of 3-nitrostyrene: metal-carbon interaction

Article abstract of DOI:10.1039/C8CC07430E

Constructing Pd-C bond between Pd particles and defective hollow nanocarbons (h-NCs) not only enables facile H₂ dissociation but also diffusion of the dissociated H species, which makes the Pd/h-NC highly active with a TOF of 21?845 h^?1 (>80 times higher than that of the best catalyst in literature), selective (97%), and stable (4 cycles) for selective hydrogenation of 3-nitrostyrene to 3-ethylnitrobenze.

Full text of DOI:10.1039/C8CC07430E

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Hollow carbon anchored highly dispersed Pd
species for selective hydrogenation of
3-nitrostyrene: metal-carbon interaction†
Cite this: Chem. Commun., 2018,
54, 13248
Received 12th September 2018,
Accepted 19th October 2018
Yang Lou,
Jia Xu, Honglu Wu
and Jingyue Liu
*
DOI: 10.1039/c8cc07430e
rsc.li/chemcomm
Constructing Pd–C bond between Pd particles and defective hollow selectivity but at the expense of activity.11–13 For example, the
nanocarbons (h-NCs) not only enables facile H2 dissociation but also addition of alkali ions enables modulating the electronic proper-
diffusion of the dissociated H species, which makes the Pd/h-NC highly ties of supported active metal species, which controls the activity
active with a TOF of 21 845 hÀ1 (480 times higher than that of the best and selectivity for 3-nitrostyrene hydrogenation.11 Metal alloying is
catalyst in literature), selective (97%), and stable (4 cycles) for selective considered another efficient method to tune the electronic proper-
hydrogenation of 3-nitrostyrene to 3-ethylnitrobenze.
ties of active metal species and correspondingly enhance their
catalytic performance.8,9,14 Another approach is to choose the
Catalytic hydrogenation is considered an environmentally friendly appropriate reducible oxides as supports that can influence the
and efficient process for hydrogenation of nitroarenes to produce catalytic activity and selectivity of the active phases via strong
versatile intermediates for production of dyes, pharmaceuticals, metal-support interactions.1,15,16
flavors, agrochemicals and polymers.1–4 However, a catalyst that
For liquid phase reactions, carbon supports have been widely
possesses both high activity and selectivity, especially in the used because of their high chemical stability in either acid or base
presence of two or more reducible functional groups (e.g. selective solvents, high mechanical stability, high total surface area, and
hydrogenation of nitrostyrene), under mild reaction conditions is unique electronic properties.17,18 Graphitic carbon materials are
highly desirable. Most of the available supported metal catalysts generally not appropriate for anchoring metal species, especially
cannot meet such a demanding goal of selective hydrogenation. noble metals, due to the chemical inertness of the graphite basal
For example, unmodified Pd-based catalysts normally lead to planes.19 Therefore, strategies for engineering defects (e.g., topo-
overly hydrogenated products attributable to the strong hydroge- logical, dangling bonds, rehybridization and other types of
nation ability of Pd particles.5–7 For selective hydrogenation of defects20,21) of, introducing functional groups to, and/or incorpor-
targeted molecules and products, one needs to consider both the ating heteroatoms in, carbon structures have been proposed to
H2 activation process and the adsorption strength of dissociated strengthen the electronic interaction between active metal species
H atoms on the surfaces of the active species.8,9 A catalyst that and the functional moieties or defects on carbon surfaces.21,22 In
exhibits facile activation of H2 and weak adsorption of the this work, we propose a new strategy to enhance the catalytic
dissociated H atoms can exhibit optimal efficiency in balancing activity and selectivity for selective hydrogenation reactions: con-
activity and selectivity for the targeted product.8,10 The electronic structing strong metal–carbon bonding to finely tune the electronic
properties of active metal species play a crucial role in determining structure of active metal species through strong electronic inter-
the adsorption behavior of functional groups and the dissociation action between metal particles and edge/defect sites of carbon
behavior of H2.3,5,11 Hence, how to efficiently tune the electronic supports.
properties of active species/sites is critical to enhancing a catalyst’s
overall performance for selective hydrogenation reactions.
In this present study, we fabricated hollow nanocarbons
(h-NCs) that possess high number density of surface edge/defect
The use of transition metals or other types of additives to sites, high total surface area, and highly accessible mesopores. Our
modify the electronic structure of active sites can enhance concurrent research work has confirmed that these edge/defect
sites of the synthesized h-NCs efficiently modulate the electronic
Department of Physics, Arizona State University, Tempe, Arizona 85287, USA.
structure of anchored single Pt atoms and significantly enhance
their chemical reactivity. We hypothesize that strong interaction
between small Pd clusters and the carbon edge atoms forming
E-mail: jingyue.liu@asu.edu
† Electronic supplementary information (ESI) available: Experimental details,
HAADF-STEM images of h-NCs and Pd1/h-NC SAC; defect density, Raman and
Pd–C bonds can tune the hydrogenation ability of the Pd clusters
to a degree that both the H2 dissociation and the adsorption of the
XPS spectra of Pd/HC and Pd/XC-72 catalysts; activity and selectivity comparison
with other published catalysts. See DOI: 10.1039/c8cc07430e
13248 | Chem. Commun., 2018, 54, 13248--13251
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Table 1 Catalytic activity and selectivity of selective hydrogenation of
dissociated H atoms are appropriate for the targeted selective
hydrogenation of 3-nitrostyrene to 3-ethylnitrobenze with high
activity and selectivity.
3-nirostyrene over carbon supported Pd catalystsa
Selectivity/%
Our experimental results demonstrate that the synthesized
h-NCs supported Pd particles are highly active and selective for
the hydrogenation of 3-nitrostyrene to 3-ethylnitrobenze, under very
mild reaction conditions (40 1C and 5 bar H2) with ethanol as the
reaction medium, with a selectivity of 97% and a turnover frequency
(TOF) as high as 21 845 per Pd atom per hour (21 845 hÀ1), more
than 80 times higher than that of the best catalyst reported in
literature.23
The h-NCs are synthesized by a template-assisted catalytic deposi-
tion and evaporation process by using ZnO nanowires as template
(see sample preparation details in the supporting materials). The
h-NCs possess a BET surface area of B1100 m2 gÀ1 and a tube
Catalyst
Conversion/%
3-VA
3-EA
3-ENB
Other
Pd/h-NC
94.9
12.8
99.9
24.2
0
0
7
0
3.7
0
3.0
12.8
50.4
13.7
0
97.0
80.2
37.5
82.7
0
0
0
12.1
0
0
0
Pd/XC-72
10 wt% Pd/Cb
Pd1/h-NC
Pure h-NCc
Pure XC-72d
0
0
0
0
a
Reaction conditions: 40 1C for 10 min, 5bar H2 as hydrogen donor,
8 ml ethanol as reaction solvent, 0.33 mmol 3-nitrostyrene, Pd/substrate
ratio is 0.14%. 3-VA: 3-vinylaniline; 3-EA: 3-ethylaniline; 3-ENB:
b
3-ethylnitrobenze. Commercial 10 wt% Pd/C from Sigma-Aldrich.
c
d
Reaction time is 60 min. Reaction time is 30 min.
morphology with inner diameters ranging from 20 to 100 nm and carbon, widely used in a variety of catalytic reactions,25 was used to
lengths ranging from 1 to 20 micrometers (Fig. S1, ESI†). The wall synthesize a control catalyst. The XC-72 carbon, with a BET surface
thicknesses of the h-NCs range from 2–5 nm with numerous area of 254 m2 gÀ1, consists of aggregated spherical particles with a
mesopores (an average pose diameter of B4.3 nm) on the side walls compact, onion-like graphitic structure (Fig. S4, ESI†). The Pd
(Fig. S2, ESI†). The synthesized h-NCs consist of stacked hyper-cross- particles supported on the XC-72 carbon powders (Fig. 1b), denoted
linked graphene sheets with sizes ranging from 0.5 to 3.1 nm, as Pd/XC-72 with a Pd loading of 0.58 wt%, have slightly larger sizes
resulting in disordered and defective graphene-like structures with an average size of 3.1 Æ 0.1 nm.
(Fig. S3, ESI†). The presence of numerous edge sites in the synthe-
sized h-NCs can be effectively utilized to anchor single metal atoms, hydrogenation of 3-nitrostyrene with a selectivity of 97.0% toward
clusters or nanoparticles. 3-ethylnitrobenzene under mild reaction conditions (40 1C and 5 bar
As shown in Table 1, the synthesized Pd/h-NC is highly active for
The aberration-corrected high-angle annular dark-field scanning H2). The 3-ethylaniline was the only by-product and hydroxylamine
transmission electron microscopy (HAADF-STEM) imaging techni- or other types of side products were not detectable. The catalyst
que (Fig. 1), indispensable for determining the dispersion of maintained its selectivity (491%) toward 3-ethylnitrobenzene even
supported metal catalysts,24 was used to examine the spatial and after 4 cycles (Fig. S5, ESI†). Electron microscopy characterizations
size distribution of Pd particles supported on the h-NCs (denoted as and metal analyses did not reveal recognizable sintering of Pd
Pd/h-NC with Pd loading of 0.49 wt%): The Pd particles are nanoparticles (Fig. S6, ESI†) or leaching of Pd during the catalytic
uniformly distributed across the h-NCs with an average size of reactions. The slight decrease in conversion rate during the stability
2.8 Æ 0.2 nm. To compare with literature results, the Vulcan XC-72 test originated from the loss of catalyst powders during the filtering
processes since we used only 5 mg catalysts for the hydrogenation
reactions. The TOF of the Pd/h-NC was calculated to be 21845 hÀ1
,
B84 times higher than that of the best catalyst reported in
literature.23 The recently developed single-atom catalysts (SACs)
normally exhibit high selectivity toward selective hydrogenation
reactions due to the uniformity of isolated active sites.26–30 However,
when downsizing the Pd particles to single atoms (Fig. S7, ESI†) the
Pd1/h-NC SAC (with a Pd loading of 0.19 wt%) exhibited a much
lower selectivity toward 3-ethylnitrobenze (82.7%) under the same
reaction conditions (Table 1) although the TOF was estimated to be
22 070 hÀ1, similar to that of the Pd/h-NC catalyst. Compared to
other highly selective catalysts for hydrogenation of 3-nitrostyrene
(Table S1, ESI†), the use of ethanol as the reaction medium, as
practiced here on the synthesized Pd/h-NC, is much greener
and more environmentally friendly than that by using toxic
and/or environmentally unfriendly solvents such as heptane,
toluene, and tetrahydrofuran as the reaction medium to
enhance the catalytic selectivity of 3-nitrostyrene hydrogenation
to 3-ethylnitrobenze.4,14,23,31,32 The catalytic evaluation results
indicate that the Pd/h-NC catalyst not only provides better
performance but also enables catalytic transformation of
important molecules in a more environmentally friendly reac-
tion medium.
Fig. 1 HAADF-STEM images and particle size distributions of fresh Pd/h-
NC and Pd/XC-72.
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When different types of carbon supports were used the corres- particles.42–44 The strong edge anchoring of the Pd particles not
ponding supported Pd catalysts exhibited much lower selectivity only makes them stable during hydrogenation reactions but also
toward 3-ethylnitrobenzene (Table 1). For example, the commercial tunes their catalytic properties to yield higher selectivity for
Pd/C catalyst (purchased from Sigma-Aldrich) yielded a selectivity hydrogenation of 3-nitrostyrene to 3-ethylnitrobenze.
of only 37.5% toward 3-ethylnitrobenzene and the reaction product
When the Pd particles were deposited on the XC-72, the ID1/IG
was dominated by 3-ethylaniline. Furthermore, the total activity for ratio dropped only slightly by B1% compared to that of the pure
hydrogenation of 3-nitrostyrene on the commercial Pd/C catalyst XC-72 (Fig. S9, ESI†), suggesting that the deposition of the Pd
(TOF = 8768 hÀ1) was much lower than on the Pd/h-NC. The particles did not significantly affect the carbon structure due to a
selectivity toward 3-ethylnitrobenzene on the control Pd/XC-72 weak interaction between them. The slight decrease (6–8%) of defect
catalyst was 80.2% with a total TOF of 9300 hÀ1, B2.3 times lower number density (Table S2, ESI†) further indicates that the graphitic
than that on the Pd/h-NC catalyst. The pure h-NCs and XC-72 XC-72 carbon cannot efficiently bond with and anchor Pd particles,
carbon, under the same reaction conditions, were not active resulting in the lower stability of the Pd/XC-72 catalyst during
(Table 1). These results suggest that the physicochemical proper- selective hydrogenation of 3-nitrostyrene to 3-ethylnitrobenze.
ties of the carbon supports play a significant role in determining
both the selectivity and activity of selective hydrogenation of supported Pd nanoparticles, the X-ray photoelectron spectroscopy
3-nitrostyrene on carbon supported Pd nanoparticle catalysts. (XPS) experiments were conducted on the Pd/h-NC and Pd/XC-72
In order to further unravel the electronic properties of the
In order to understand why the Pd/h-NC catalyst is more active catalysts (Fig. S10, ESI†). After a deconvolution processing of the
and selective, we characterized this catalyst in detail. With similar Pd 3d5/2 peak obtained on the Pd/XC-72, the two peaks located at
Pd loading, the HAADF-STEM images show that the size and 338.0 eV and 337.3 eV were assigned to the oxidation states of
spatial distribution of the Pd particles are similar in both the PdO2 and PdO, respectively.45,46 For the Pd/h-NC catalyst, the two
Pd/h-NC and the Pd/XC-72 catalysts, suggesting that the size and peaks are located at 337.9 eV (assignable to the PdO2 species) and
shape of the Pd particles may not play a significant role in 337.0 eV. The peak at 337.0 eV, however, is between the values of
differentiating the performance of these two catalysts. The geo- Pd1+ (335.5 eV) and Pd2+ (337.3 eV).47 Therefore, this peak can be
metric and electronic properties of the carbon supports play an attributed to the electron-depleted Pd atoms (Pdn+, 1 o n o 2),
important role in stabilizing metal species and tuning their resulting from electron transfer from the Pd species to the carbon
electronic properties.33 Raman spectroscopy, capable of providing support,33 corroborating the Raman result (Fig. S8, ESI†). Under
useful information on the density of defects in carbon hydrogenation reaction conditions, the Pd oxide species can be
materials,34–36 was used to characterize the as-prepared h-NCs easily reduced to metallic state and form PdHx species,48 resulting
and the XC-72. The peak at 1591 cmÀ1 of the Raman spectra in decrease of selectivity.5 The carbon-bonded Pd species maintain
(Fig. S8 and S9, ESI†) is assigned to the G-band, corresponding to their valence state due to charge transfer and the electron deple-
the bond stretch of all pairs of sp2 in both carbon ring and chain tion induces downshift of the d-band center of the Pdn+ species
and the peak at 1345 cmÀ1 is assigned to the D1-band, corres- and thus reduces the binding strength of the dissociatively
ponding to the defects within the carbon structure.37 The ratio adsorbed hydrogen.5,49 The weakly bound, active hydrogen species
between the D1 and G band intensities (ID1/IG) is used to quantify associated with the interfacial regions between the Pd particles
the degree of structural disorder in the carbon materials.34 The and the graphene pieces enable selective hydrogenation on Pd/h-
ID1/IG value of the h-NCs was estimated to be B1.1 while that of the NC catalyst with high activity.8,9,50
XC-72 was estimated to be B0.85 (Fig. S7 and S8, ESI†), suggesting
The active centers that weakly bind dissociated hydrogen species
that the defect density in the h-NCs is much higher.38,39 Based on the may exhibit high selectivity but they often have high activation
empirical formula models,40,41 we estimated that the crystallite size energy for H2 dissociation since the activation energy of a reaction is
(related to the amount of crystal boundary, including dislocations, usually inversely proportional to the adsorption strength of the
vacancies and so on)35 of the h-NCs (B6.6 nm) is much smaller than intermediates, limiting the activity of these catalysts.8,50,51 In order
that of the XC-72 (B14.2 nm). Correspondingly, the defect density of to unravel the nature of H2 activation on the h-NC supported Pd
the h-NCs is roughly 5 times higher than that of the XC-72 (Table S2, particles, we conducted the hydrogen oxidation experiment on the
ESI†). Both the atomic resolution STEM images and the Raman Pd/h-NC and Pd/XC-72 catalysts. In the temperature range of 20 1C
spectra confirm the existence of numerous edge defect sites in the to 50 1C, the H2 reaction rate on the Pd/h-NC is much higher than
synthesized h-NCs.
that on the Pd/XC-72 (Fig. S11a and b, ESI†). The activation energy
When the Pd particles were deposited on the h-NCs, the ID1/IG (Ea) of H2 oxidation on the Pd/h-NC is 11 kJ molÀ1 while the Ea of
ratio dropped by B19% (Fig. S8, ESI†) and the defect density the Pd/XC-72 is 31 kJ molÀ1, clearly suggesting that the h-NC
dropped by B20% (Table S2, ESI†). The significant decrease in the supported Pd nanoparticles can much more easily dissociate H2.
ID1/IG ratio and the defect density is most probably a result of From the above experiments we conclude that when compared with
strong metal-support interaction: the Pd particles interacted with that on the Pd/XC-72, the synthesized Pd/h-NC catalyst provides
the edges/defects of the h-NCs to form strong Pd-carbon bonds. It more activated and weakly bound hydrogen species. As a result, the
has been reported that hybridization of the d orbitals of the Pd Pd/h-NC catalyst exhibits the excellent activity and selectivity for
atoms with the s and p orbitals of the adjacent C atoms leads to selective hydrogenation of 3-nitrostyrene.
strong electronic interaction and electron transfer from the Pd
In summary, we developed a mesoporous nanocarbon
particles to the carbon support, resulting in positively charged Pd supported Pd nanoparticle catalyst for selective hydrogenation of
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16 M. Boronat, P. Concepcion, A. Corma, S. Gonzalez, F. Illas and
P. Serna, J. Am. Chem. Soc., 2007, 129, 16230–16237.
17 D. S. Su, G. Wen, S. Wu, F. Peng and R. Schlogl, Angew. Chem., Int.
Ed., 2017, 56, 936–964.
18 J. Zhu, A. Holmen and D. Chen, ChemCatChem, 2013, 5, 378–401.
19 S. A. Park, D. S. Kim, T. J. Kim and Y. T. Kim, ACS Catal., 2013, 3,
3067–3074.
20 T. W. Ebbesen and T. Takada, Carbon, 1995, 33, 973–978.
21 J. C. Charlier, Acc. Chem. Res., 2002, 35, 1063–1069.
22 V. Lordi, N. Yao and J. Wei, Chem. Mater., 2001, 13, 733–737.
23 M. J. Beier, J. M. Andanson and A. Baiker, ACS Catal., 2012, 2,
2587–2595.
24 J. Liu, Chin. J. Catal., 2017, 38, 1460–1472.
25 J. Xia, G. He, L. Zhang, X. Sun and X. Wang, Appl. Catal., B, 2016,
180, 408–415.
26 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.
27 X. F. Yang, A. Q. Wang, B. T. Qiao, J. Li, J. Y. Liu and T. Zhang, Acc.
Chem. Res., 2013, 46, 1740–1748.
the CQC bond in the presence of –NO2 (selective hydrogenation of
3-nitrostyrene). The presence of high number density edge/defect
sites in the synthesized h-NCs enhances the interaction between
Pd species and the carbon support, resulting in electron transfer
from Pd to carbon and thus forming a strong Pd–C bond. Such
strong electronic interaction not only enables facile H2 dissocia-
tion but also enhances the diffusion of the dissociated H species.
The synthesized Pd/h-NC catalyst yielded a selectivity of 97%,
stable up to 4 cycles, and a TOF of 21 845 hÀ1 for selective
hydrogenation of 3-nitrostyrene to 3-ethylnitrobenzene, more than
80 times higher than that of the best catalyst reported in
literature.23 This work provides insights in understanding the
effect of anchoring metal nanoparticles by edge/defect sites in
carbon supports on selective hydrogenation reactions. The strategy
of engineering carbon edge/defect sites to anchor Pd nanoparticles
to tune catalytic properties can be applied to other types of metals
for various types of catalytic reactions.
28 J. Y. Liu, ACS Catal., 2017, 7, 34–59.
29 B. C. Gates, M. Flytzani-Stephanopoulos, D. A. Dixon and A. Katz,
Catal. Sci. Technol., 2017, 7, 4259–4275.
30 A. Wang, J. Li and T. Zhang, Nat. Rev. Chem., 2018, 2, 65–81.
This work was supported by the National Science Foundation
under CHE-1465057. The authors gratefully acknowledge the use
of facilities within the Eyring Materials Center and the John M.
Cowley Center for High Resolution Electron Microscopy at Arizona
State University.
˘
31 M. M. Trandafir, L. Pop, N. D. Hadade, M. Florea, F. Neatu, C. M.
ˆ
Teodorescu, B. Duraki, J. A. van Bokhoven, I. Grosu, V. I. Parvulescu
and H. Garcia, Catal. Sci. Technol., 2016, 6, 8344–8354.
32 T. Ishida, Y. Onuma, K. Kinjo, A. Hamasaki, H. Ohashi, T. Honma,
T. Akita, T. Yokoyama, M. Tokunaga and M. Haruta, Tetrahedron,
2014, 70, 6150–6155.
33 R. G. Rao, R. Blume, T. W. Hansen, E. Fuentes, K. Dreyer, S. Moldovan,
O. Ersen, D. D. Hibbitts, Y. J. Chabal, R. Schlogl and J. P. Tessonnier,
Nat. Commun., 2017, 8, 340.
Conflicts of interest
¨
34 A. Sadezky, H. Muckenhuber, H. Grothe, R. Niessner and U. Poschl,
Carbon, 2005, 43, 1731–1742.
There are no conflicts to declare.
35 F. Tuinstra and J. L. Koenig, J. Compos. Mater., 1970, 4, 492–499.
36 A. C. Ferrari and J. Robertson, Phys. Rev. B: Condens. Matter Mater.
Phys., 2000, 61, 14095–14107.
37 K. Teii, S. Shimada, M. Nakashima and A. T. H. Chuang, J. Appl.
Phys., 2009, 106, 084303.
Notes and references
1 A. Corma and P. Serna, Science, 2006, 313, 332–334.
2 G. Booth, Ullmann’s Encyclopedia of Industrial Chemistry, Wiley-VCH, 38 L. Wang, Z. Sofer, D. Bousa, D. Sedmidubsky, S. Huber, S. Matejkova,
Weinheim, 2012, ch. 2.
3 H. U. Blaser, H. Steiner and M. Studer, ChemCatChem, 2009, 1,
210–221.
4 L. Huang, P. Luo, W. Pei, X. Liu, Y. Wang, J. Wang, W. Xing and
J. Huang, Adv. Synth. Catal., 2012, 354, 2689–2694.
5 M. Armbru¨ster, M. Behrens, F. Cinquini, K. Fottinger, Y. Grin,
A. Michalcova and M. Pumera, Angew. Chem., Int. Ed., 2016, 55,
13965–13969.
39 G. Wen, B. Wang, C. Wang, J. Wang, Z. Tian, R. Schlogl and D. S. Su,
Angew. Chem., Int. Ed., 2017, 56, 600–604.
40 J. H. Zhong, J. Zhang, X. Jin, J. Y. Liu, Q. Li, M. H. Li, W. Cai,
D. Y. Wu, D. Zhan and B. Ren, J. Am. Chem. Soc., 2014, 136,
16609–16617.
¨
¨
A. Haghofer, B. Klotzer, A. Knop-Gericke, H. Lorenz, A. Ota, S. Penner,
´
J. Prinz, C. Rameshan, Z. Revay, D. Rosenthal, G. Rupprechter, P. Sautet, 41 L. G. Cançado, K. Takai, T. Enoki, M. Endo, Y. A. Kim, H. Mizusaki,
¨
´
˜
R. Schlogl, L. Shao, L. Szentmiklosi, D. Teschner, D. Torres, R. Wagner,
A. Jorio, L. N. Coelho, R. Magalhaes-Paniago and M. A. Pimenta,
R. Widmer and G. Wowsnick, ChemCatChem, 2012, 4, 1048–1063.
Appl. Phys. Lett., 2006, 88, 163106.
42 I. Efremenko, J. Catal., 2003, 214, 53–67.
´
6 A. Borodzinski and G. C. Bond, Catal. Rev., 2006, 48, 91–144.
7 M. Chen, D. Kumar, C. W. Yi and D. W. Goodman, Science, 2005, 43 T. Prasomsri, D. Shi and D. E. Resasco, Chem. Phys. Lett., 2010, 497,
310, 291–293. 103–107.
8 F. R. Lucci, M. T. Darby, M. F. Mattera, C. J. Ivimey, A. J. Therrien, 44 F. Cardenas-Lizana, Y. Hao, M. Crespo-Quesada, I. Yuranov,
´
A. Michaelides, M. Stamatakis and E. C. Sykes, J. Phys. Chem. Lett.,
2016, 7, 480–485.
X. Wang, M. A. Keane and L. Kiwi-Minsker, ACS Catal., 2013, 3,
1386–1396.
9 G. Kyriakou, M. B. Boucher, A. D. Jewell, E. A. Lewis, T. J. Lawton, 45 Y. Lou, J. Ma, W. D. Hu, Q. G. Dai, L. Wang, W. C. Zhan, Y. L. Guo,
A. E. Baber, H. L. Tierney, M. Flytzani-Stephanopoulos and
E. C. H. Sykes, Science, 2012, 335, 1209–1212.
10 F. R. Lucci, M. D. Marcinkowski, T. J. Lawton and E. C. H. Sykes,
J. Phys. Chem. C, 2015, 119, 24351–24357.
X. M. Cao, Y. Guo, P. Hu and G. Z. Lu, ACS Catal., 2016, 6, 8127–8139.
46 R. Rahul, R. K. Singh, B. Bera, R. Devivaraprasad and M. Neergat,
Phys. Chem. Chem. Phys., 2015, 17, 15146–15155.
47 Z. Zhao, X. Huang, M. Li, G. Wang, C. Lee, E. Zhu, X. Duan and
Y. Huang, J. Am. Chem. Soc., 2015, 137, 15672–15675.
11 H. Wei, Y. Ren, A. Wang, X. Liu, X. Liu, L. Zhang, S. Miao, L. Li, J. Liu,
J. Wang, G. Wang, D. Su and T. Zhang, Chem. Sci., 2017, 8, 5126–5131. 48 Y. Feng, L. Zhou, Q. Wan, S. Lin and H. Guo, Chem. Sci., 2018, 9,
´
´
12 M. Makosch, W. I. Lin, V. Bumbalek, J. Sa, J. W. Medlin, K. Hungerbu¨hler
5890–5896.
and J. A. van Bokhoven, ACS Catal., 2012, 2, 2079–2081.
49 K. Namba, S. Ogura, S. Ohno, W. Di, K. Kato, M. Wilde, I. Pletikosic,
P. Pervan, M. Milun and K. Fukutani, Proc. Natl. Acad. Sci. U. S. A.,
2018, 115, 7896–7900.
50 J. K. Nørskov, T. Bligaard, A. Logadottir, S. Bahn, L. B. Hansen,
M. Bollinger, H. Bengaard, B. Hammer, Z. Sljivancanin, M. Mavrikakis,
Y. Xu, S. Dahl and C. J. H. Jacobsen, J. Catal., 2002, 209, 275–278.
51 B. Hammer and J. K. Norskov, Nature, 1995, 376, 238–240.
¨
13 K. Mobus, D. Wolf, H. Benischke, U. Dittmeier, K. Simon,
U. Packruhn, R. Jantke, S. Weidlich, C. Weber and B. Chen, Top.
Catal., 2010, 53, 1126–1131.
14 S. Furukawa, Y. Yoshida and T. Komatsu, ACS Catal., 2014, 4, 1441–1450.
15 A. Corma, P. Serna, P. Concepcion and J. J. Calvino, J. Am. Chem.
Soc., 2008, 130, 8748–8753.
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