In Situ Raman Monitoring and Manipulating of Interfacial Hydrogen Spillover by Precise Fabrication of Au/TiO2/Pt Sandwich Structures

Article abstract of DOI:10.1002/anie.202000426

The spillover of hydrogen species and its role in tuning the activity and selectivity in catalytic hydrogenation have been investigated in situ using surface-enhanced Raman spectroscopy (SERS) with 10 nm spatial resolution through the precise fabrication

Full text of DOI:10.1002/anie.202000426

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Accepted Article
Title: In situ Raman monitoring and manipulating of interfacial
hydrogen spillover via precise fabrication of Au/TiO2/Pt sandwich
structures
Authors: Jie Wei, Si-Na Qin, Jing-Li Liu, Xiang-Yu Ruan, Zhiqiang
Guan, Hao Yan, Di-Ye Wei, Hua Zhang, Jun Cheng,
Hongxing Xu, Zhong-Qun Tian, and Jian-Feng Li
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To be cited as: Angew. Chem. Int. Ed. 10.1002/anie.202000426
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COMMUNICATION
In situ Raman monitoring and manipulating of interfacial hydrogen
spillover via precise fabrication of Au/TiO /Pt sandwich structures
2
[
a]
[a]
[a]
[b]
[b]
[a]
[a]
Jie Wei, Si-Na Qin, Jing-Li Liu, Xiang-Yu Ruan, Zhiqiang Guan, Hao Yan, Di-Ye Wei, Hua
[
a]
[a]
[b]
[a]
[a],[c]
Zhang,* Jun Cheng, Hongxing Xu, Zhong-Qun Tian, and Jian-Feng Li*
Abstract: Understanding the activation and transfer of hydrogen
species at interfacial sites is essential for catalytic hydrogenation, yet
still remains a significant challenge. Herein, the spillover of hydrogen
species and its role in tuning the activity and selectivity in catalytic
hydrogenation have been investigated in situ using surface-enhanced
Raman spectroscopy (SERS) with 10 nm spatial resolution through
hydrogenation of species adsorbed there.[5] It significantly affects
the intrinsic catalytic behavior of catalysts thus changes their
activity or selectivity.[6] Consequently, great efforts have been
denoted to promoting the understanding on hydrogen spillover.
Temperature-programmed desorption and temperature-
[
7]
programmed reduction studies first evidence the existence of
hydrogen spillover between metals and oxides.[8] Recently,
the precise fabrication of Au/TiO
SERS study reveals that hydrogen species can efficiently spillover at
Pt-TiO -Au interfaces, and the ultimate spillover distance on TiO is
50 nm. Combining kinetic isotope experiment and density functional
2
/Pt sandwich nanostructures. In situ
2 2 3
hydrogen spillover at Pd-Cu and Pt-TiO -Fe O interfaces was
2
2
directly observed using scanning tunneling microscopy and
~
single-particle
X-ray
absorption
spectromicroscopy,
respectively.[ Density functional theory (DFT) calculations
indicate hydrogen spillover might proceed via the migration of
proton and electron pairs on the surface.[10]
9]
theory calculation, we find that the hydrogen spillover proceeds via
the water-assisted cleavage and formation of surface hydrogen-
oxygen bond. More importantly, the selectivity in the hydrogenation of
the nitro or isocyanide group is manipulated by controlling the
hydrogen spillover. This work provides molecular insights to deepen
the understanding of hydrogen activation and boosts the design of
active and selective catalysts for hydrogenation.
Nevertheless, more insightful information, especially that is
acquired in situ, is needed to understand hydrogen spillover at a
molecular level. Surface-enhanced Raman spectroscopy (SERS)
is an ultrasensitive vibrational technique that can provide
fingerprint molecular information,[ thus is promising for tracking
catalytic reactions in situ.[12] Using in situ SERS, we have directly
proved that hydrogen species can be transferred across the Pt-
11]
The development of efficient catalysts relies on the insightful
understanding of the reaction mechanism and structure-activity
Au and Pt-TiO
2
-Au interfaces, but would be blocked at the Pt-
[
1]
relationship. An outstanding catalyst usually consists of different
catalytic sites that function individually, at the same time, interact
synergistically or work cooperatively to achieve the catalytic
cycle.[2] Therefore, revealing the fundamental interactions among
different active sites and their influence on the catalytic behaviors
is emerging as a central issue yet a major challenge in catalysis.[
One typical example is the interfacial hydrogen spillover
phenomenon in catalytic hydrogenation.[4]
SiO
2
-Au interfaces.[13] However, more fundamental aspects about
hydrogen spillover, including the distance and molecular
mechanism of hydrogen spillover and its influence on the catalytic
performance, still remain unclear.
Herein, hydrogen spillover at Pt-TiO -Au interfaces and its
2
influences on selective hydrogenation of the nitro group have
been investigated with nanoscale spatial resolution. An exquisite
3]
Au/TiO
activation of hydrogen, hydrogen spillover, and hydrogenation
reaction to proceed separately on Pt, TiO , and Au. Combining in
situ SERS study, kinetic isotope experiment, and DFT calculation,
we find that hydrogen species can efficiently spillover on the TiO
2
/Pt sandwich nanostructure is fabricated, allowing the
Hydrogen spillover is a ubiquitous interfacial process in which
active hydrogen species generated on one site via the
dissociation of H may migrate to other sites and participate in the
2
2
2
surface for 50 nm via the cleavage and formation of hydrogen-
oxygen bond linked to titanium. Moreover, the selectivity of the
hydrogenation of the nitro group in the presence of an isocyanide
group can be significantly improved by precisely manipulating the
hydrogen spillover distance.
Generally, the active sites for hydrogen activation and
molecule hydrogenation in most traditional catalysts are the same
or locate so close to each other that it is too challenging to
investigate these processes separately. To overcome this
[
a]
J. Wei, S. N. Qin, J. L. Liu, H. Yan, D. Y. Wei, Prof. H. Zhang, Prof.
Z. Q. Tian, Prof. J. Cheng, Prof. J. F. Li
State Key Laboratory of Physical Chemistry of Solid Surfaces,
iChEM, College of Chemistry and Chemical Engineering, Fujian Key
Laboratory of Advanced Materials, College of Materials, College of
Energy, Xiamen University
Xiamen, 361005, (China)
E-mail: Li@xmu.edu.cn
zhanghua@xmu.edu.cn
X. Y. Ruan, Prof. Z. Guan, Prof. H. Xu
School of Physics and Technology, Center for Nanoscience and
Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-
structures of Ministry of Education, Wuhan University
Wuhan, 430072 (China)
Shenzhen Research Institute of Xiamen University
Shenzhen, 518000 (China)
[
b]
c]
bottleneck, we design an Au/TiO
achieves the spatial isolation of the active sites for hydrogen
activation (Pt), spillover (TiO ), and hydrogenation (Au). As the Au
2
/Pt sandwich configuration that
2
[
nanoparticles used here have a very large size, they are inert
towards hydrogen activation.[14] Thus, hydrogen can only be
Supporting information for this article is given via a link at the end of
the document.
activated and dissociated to active hydrogen species at the
underlying Pt surface (Figure 1a). These hydrogen species will
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Angewandte Chemie International Edition
10.1002/anie.202000426
COMMUNICATION
spillover along the TiO
2
surface to the Au nanoparticles and
substrate, forming the Au/TiO
(denoted as Au/x-nm-TiO
of the TiO layer). The multilayer structure of Au/TiO
illustrated by the cross-sectional TEM image in Figure 1e. The
TiO layer is sandwiched between the Pt film and the Au
nanoparticle monolayer. Such a sandwich structure is further
confirmed by scanning transmission electron microscope (STEM),
elemental mapping and scanning electron microscope (SEM)
(Figures 1f and S4).
2
/Pt multilayer nanostructure
trigger the hydrogenation of molecules adsorbed there.
Meanwhile, the Au nanoparticles can generate strong
electromagnetic fields to significantly enhance the Raman signals
of species nearby,[15] allowing the in situ Raman monitoring of the
hydrogenation reaction.[16] Therefore, interfacial hydrogen
spillover can be in situ investigated using such a configuration,
and the spillover distance can be precisely measured and
2
/Pt, where x-nm indicates the thickness
/Pt is clearly
2
2
2
manipulated by simply changing the thickness of the TiO
2
layer.
Guided by the above idea, a monolayer of TiO nanoparticles
2
2 2
As mentioned above, Pt, TiO , and Au in the Au/TiO /Pt
with a diameter of ~10 nm was prepared via the Langmuir-
Blodgett (LB) method (Figure 1b and S1) and deposited on a Pt
film (Figure S2). The atomic force microscope (AFM)
sandwich nanostructure work as the active sites for hydrogen
dissociation, spillover, and hydrogenation, respectively. To test
such an idea and confirm that the Au nanoparticles are unable to
activate hydrogen, we first investigate the hydrogenation of pNTP
on bare Au nanoparticles and Au/Pt nanocomposites. No reaction
happens on bare Au nanoparticles, but pNTP is efficiently
hydrogenated to para-aminothiophenol (pATP) on Au/Pt (Figures
S5 and S6). These results corroborate that the hydrogen can only
be activated on the Pt surface and the active hydrogen species
generated on Pt will migrate across the Pt-Au interfaces and
hydrogenate pNTP adsorbed on Au to pATP.
characterization illustrates that the height of the TiO
is ~10 nm (Figure 1c), well consistent with the TEM results.
Furthermore, the height of the TiO , i.e., the hydrogen spillover
distance, can be tuned from 10 to 50 nm by increasing the number
of the TiO layers (Figure 1d). Finally, a monolayer of 55 nm Au
2
monolayer
2
2
nanoparticles with para-nitrothiophenol (pNTP), the probe
molecule for the hydrogenation reaction, adsorbed on their
surface was prepared (Figure S3) and transferred on the TiO /Pt
2
Figure 1. a) Schematic illustration of hydrogen spillover on Au/TiO
the TiO nanoparticle monolayer assembled on a smooth Pt film (TiO
Cross-sectional TEM image and f) elemental mapping of the Au/TiO /Pt sandwich nanostructure using a focused ion beam (FIB) system, respectively. Pt signals
2
/Pt sandwich nanostructures. b) TEM image of a TiO
2
nanoparticle monolayer. c) AFM image of
2
2
/Pt). d) Cross-sectional SEM images of TiO /Pt structure with 10, 30, and 50 nm TiO
2
2
. e)
2
on the top region in f) result from the Pt nanoparticles introduced during the TEM sample preparation using FIB. The scale bar of all panels is 50 nm, except that of
panel c) is 500 nm.
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The hydrogenation of pNTP was further investigated on the
0.34 eV, well consistent with the activation energy from the
Arrhenius plots. Without water, electron and proton transfer occur
in a concerted manner with a much higher activation energy of
3.09 eV (Figure S9). These theoretical results indicate that the
Au/TiO
nm-TiO
2
/Pt sandwich nanostructures using SERS. As for Au/10-
-
1
2
/Pt, the Raman peaks at 1337 and 1570 cm , assigned
to the symmetric nitro stretching vibration and the phenyl ring
modes of pNTP, respectively, decrease gradually with the
increased reaction time (Figure 2a). Meanwhile, a new Raman
band at 1586 cm-1 attributed to the benzene ring mode of pATP
appears and rises. These results mean pNTP is efficiently
spillover of hydrogen on TiO
generation of the surface Obr-H and trace water adsorbed on the
TiO surface plays an essential role on it.
2
involves the cleavage and
2
converted into pATP on Au/10-nm-TiO
hydrogen can spillover from Pt to TiO
2
/Pt, demonstrating that
and finally reaches the
2
surface of Au. This is well consistent with our previous results,[
13]
and is reasonable in terms of that TiO
2
is a well-known “active”
support and has strong interactions with Pt or Au.[ Additional
17]
control experiments show that the spillover of hydrogen proceeds
at the TiO
2
2
surface rather than the TiO bulk phase and it cannot
2
occur at the Pt-SiO -Au interface (Figure S7).
Figure 3. a) DFT simulation of the migration of hydrogen on TiO
red, O; sliver, H; blue, Ti. b) Reaction kinetics and c) kinetic isotope effects of
the reduction of pNTP over different TiO distance using H or D
2
. Color coding:
2
2
2
.
To test the proposed mechanism, we conducted isotopic
experiments by using D in the hydrogenation of pNTP to quantify
2
the kinetic isotope effect (KIE), which is a key factor to elucidate
the reaction mechanism.[18] As shown in Figure 3b, all the
reactions using H
reaction rate becomes significantly slower when changing H
, and this trend is more obvious with the increase of the
thickness of the TiO layer. The KIE, i.e., the ratio of reaction rate
under H relative to that under D (k /k ), for Au/Pt is about 3.5
(Figure 3c), which is a typical value for primary isotope effect. The
KIE values increase to 9.9 and 13.7 for Au/10-nm-TiO /Pt and
Au/30-nm-TiO /Pt, respectively (Figure 3c). Such a big increase
of the KIE with the thickness of the TiO layer directly evidences
that the formation and cleavage of the O-H bond occur during the
2
or D
2
follow first-order kinetics. However, the
Figure 2. In situ SERS spectra of the hydrogenation of pNTP on a) Au/10-nm-
TiO /Pt and b) Au/50-nm-TiO /Pt at 60 °C. c) Time-dependent intensity of the
Raman band for pNTP (at ∼1337 cm−1) on Au/TiO
/Pt with different thicknesses
of TiO layer. d) Arrhenius plot and the activation energy (inset) for the
hydrogenation of pNTP over Au/TiO /Pt with different thicknesses of TiO layer.
2
to
2
2
D
2
2
2
2
2
2
H
D
2
2
2
Different from Au/10-nm-TiO
pNTP remains almost unchanged during the hydrogenation on
Au/50-nm-TiO /Pt (Figure 2b). Quantitatively, with the increase in
the thickness of the TiO layer from 0 to 50 nm, the rate of pNTP
hydrogenation on Au/TiO /Pt rapidly decreases, and the reaction
is almost blocked when the TiO thickness is 50 nm (Figure 2c).
These results manifest that the thickness of the TiO layer
strongly influences hydrogen spillover and the hydrogen spillover
distance on TiO is less than 50 nm under the test conditions. The
Arrhenius plots based on kinetic studies demonstrate that the
activation energy slightly increases with the thickness of the TiO
2
/Pt, the in situ SERS spectra of
2
2
2
2
spillover of hydrogen species on TiO
DFT calculations.
2
, well consistent with the
2
2
More importantly, hydrogen spillover can be used to tune the
selectivity in catalytic hydrogenation. As a reaction barrier exists
during hydrogen spillover on TiO , the coverage of active
2
2
2
hydrogen species at the Au sites decreases after a longer
spillover distance (Figure 4a). The influence of the coverage of a
surface species on its chemical potential can be expressed as:[
2
19]
layer (Figures 2d and S8), implying that the spillover of active
hydrogen species is essential for the catalytic hydrogenation.
DFT calculations are performed to further reveal the
ꢃꢁ
ꢅ
ꢀ
ꢂꢃꢄ � ꢀ � ꢆꢇ ln
ꢁ
ꢁ
ꢃ∗
Where ꢃꢁ and ꢃ∗ are coverages of adsorbed species ꢈ and
fundamental mechanism of the hydrogen spillover over the TiO
2
ꢅ
available sites * on the surface, respectively, and ꢀꢁ is the
surface. As shown in Figure 3a, electron and hydrogen transfer
occur in a sequential mechanism. Hydrogen is transferred from
one bridge oxygen (Obr) to the next Obr with a water molecule
acting as a bridge for the hydrogen relay. The energy barrier is
standard chemical potential of species ꢈ at temperature T. This
means the chemical potential of the active hydrogen species after
a longer spillover distance is lower. Hence, with decreased
chemical potentials, the hydrogen species can only participate in
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the hydrogenation pathway needing lower energies, thus leading
to a higher selectivity (Figure 4a).
the hypothesis proposed in Figure 4a and demonstrate that
manipulation of the hydrogen spillover is an efficient strategy to
tune the selectivity in catalytic hydrogenation.
2
In summary, the spillover of hydrogen at Pt-TiO -Au
interfaces and its role on the activity as well as selectivity in
catalytic hydrogenation have been investigated using in situ
2
SERS through the fabrication of Au/TiO /Pt sandwich
nanostructures. In situ SERS results directly show that active
hydrogen species generated on Pt can be transferred to Au via
the TiO
species on TiO
experiment and DFT calculation reveal the molecular mechanism
of hydrogen spillover on the surface of TiO , which involves the
2
surface and the spillover distance of such hydrogen
2
is measured to be ~50 nm. Kinetic isotope
2
water-assisted cleavage and formation of surface hydrogen-
oxygen bond. Furthermore, the selectivity in catalytic
hydrogenation can be tuned by controlling the hydrogen spillover
distance. With increased hydrogen spillover distance, the
2
selectivity towards the hydrogenation of the NO group in the
presence of the N≡C group is significantly improved. This work
provides fundamental insights to boost the understanding of
hydrogen spillover at metal-oxide interfaces.
Figure 4. a) Schematic illustration of the selective hydrogenation of R-NO
the presence of R-N≡C by controlling the hydrogen spillover distance. b), c) In
situ SERS spectra of the selective hydrogenation of R-NO in the presence of
R-N≡C on Au/Pt and Au/30-nm-TiO /Pt, respectively. d) Selectivity of the
hydrogenation of R-NO in the presence of R-N≡C over Au/TiO /Pt with different
thicknesses of TiO layer.
2
in
Acknowledgements
2
This work was supported by NSFC (21925404, 21972117,
2
21703181, 21775127, and 21673187), the Fundamental
2
2
Research Funds for the Central Universities (20720190044),
Natural Science Foundation of Guangdong Province
2
To testify such a hypothesis, the selective hydrogenation of
the nitro group (pNTP, R-NO ) in the presence of the isocyanide
(
2016A030308012), and Natural Science Foundation of Fujian
2
Province (2019J01030).
group (phenyl isocyanide (PIC), R-N≡C), which is a key reaction
for the industrial production of fine chemicals,[ was studied. PIC
is vertically adsorbed on the Au surface with the C-terminus of the
N≡C group, and it can be hydrogenated then desorbed from the
surface.[21] This is demonstrated by the in situ SERS study, which
shows that the Raman peaks of PIC are gradually weakened in
2c]
Conflict of interest
[
20]
The authors declare no conflict of interest.
H
2
but remained unchanged under Ar (Figure S11).
Keywords: surface-enhanced Raman spectroscopy • in situ •
Hydrogenation of pNTP and PIC was carried out over
hydrogen spillover • catalytic hydrogenation
Au/TiO
shows the in situ SERS spectra of the selective hydrogen of R-
NO and R-N≡C over Au/Pt. The Raman bands for the N≡C and
N-O stretch mode locate at 2171 and 1337 cm , respectively.
With prolonged reaction time, both R-N≡C and R-NO are
2 2
/Pt with different thicknesses of TiO layer. Figure 4b
[1]
[2]
a) L. Liu, A. Corma, Chem. Rev. 2018, 118, 4981-5079.
a) A. A. Herzing, C. J. Kiely, A. F. Carley, P. Landon, G. J. Hutchings,
Science 2008, 321, 1331-1335; b) Q. Fu, W.-X. Li, Y. Yao, H. Liu, H.-Y.
Su, D. Ma, X.-K. Gu, L. Chen, Z. Wang, H. Zhang, B. Wang, X. Bao,
Science 2010, 328, 1141-1144; c) A. Corma, P. Serna, Science 2006,
2
-
1
2
efficiently hydrogenated on Au/Pt, leading to the simultaneous
decline of their Raman intensities. However, when using Au/30-
313, 332-334.
[
3]
4]
a) L. Cao, W. Liu, Q. Luo, R. Yin, B. Wang, J. Weissenrieder, M. Soldemo,
H. Yan, Y. Lin, Z. Sun, C. Ma, W. Zhang, S. Chen, H. Wang, Q. Guan, T.
Yao, S. Wei, J. Yang, J. Lu, Nature 2019, 565, 631-635; b) I. X. Green,
W. Tang, M. Neurock, J. T. Yates, Science 2011, 333, 736-739; c) Y.
Yamada, C. K. Tsung, W. Huang, Z. Huo, S. E. Habas, T. Soejima, C. E.
Aliaga, G. A. Somorjai, P. Yang, Nat. Chem. 2011, 3, 372-376.
S. Khoobiar, J. Phy.Chem. 1964, 68, 411-412
nm-TiO
N≡C is much slower than that of NO
mean the hydrogenation of NO is dominant on Au/30-nm-TiO
2
/Pt as the catalyst, the decrease of the Raman band of
(Figure 4c). These results
/Pt.
2
2
2
This can be further quantitatively revealed by the rate
constants of Au/Pt and Au/30-nm-TiO /Pt. The rate constant of
the hydrogenation of R-N≡C (kN≡C) is slightly bigger than that of
R-NO (kNO2) (kN≡C > kNO2) for Au/Pt (inset of Figure 4b). On the
contrary, as for Au/30-nm-TiO /Pt, kN≡C becomes much smaller
than kNO2 (kN≡C << kNO2). Thus, the selectivity towards the NO
hydrogenation is remarkably improved with the increase of the
thickness of the TiO layer (Figure 4d). Such results directly verify
2
[
[5]
a) W. C. Conner, J. L. Falconer, Chem. Rev. 1995, 95, 759-788; b) R.
Prins, Chem. Rev. 2012, 112, 2714-2738; c) M. D. Marcinkowski, A. D.
Jewell, M. Stamatakis, M. B. Boucher, E. A. Lewis, C. J. Murphy, G.
Kyriakou, E. C. H. Sykes, Nat. Mater. 2013, 12, 523-528.
2
2
2
[6]
a) J. Im, H. Shin, H. Jang, H. Kim, M. Choi, Nat. Commun. 2014, 5, 3370;
b) S. S. E. Collins, M. Cittadini, C. Pecharromán, A. Martucci, P.
Mulvaney, ACS Nano 2015, 9, 7846-7856; c) S. K. Beaumont, S.
2
This article is protected by copyright. All rights reserved.

Angewandte Chemie International Edition
10.1002/anie.202000426
COMMUNICATION
Alayoglu, C. Specht, N. Kruse, G. A. Somorjai, Nano Lett. 2014, 14,
[13] H. Zhang, X. G. Zhang, J. Wei, C. Wang, S. Chen, H. L. Sun, Y. H. Wang,
B. H. Chen, Z. L. Yang, D. Y. Wu, J. F. Li, Z. Q. Tian, J. Am. Chem. Soc.
2017, 139, 10339-10346.
4
792-4796; d) S. Wang, Z. J. Zhao, X. Chang, J. Zhao, H. Tian, C. Yang,
M. Li, Q. Fu, R. Mu, J. Gong, Angew. Chem. Int. Ed. 2019, 58, 7668-
672.
7
[14] a) B. Hammer, J. K. Norskov, Nature 1995, 376, 238-240; b) T. Fujitani,
I. Nakamura, T. Akita, M. Okumura, M. Haruta, Angew. Chem. Int. Ed.
2009, 48, 9515-9518.
[7]
a) T. Huizinga, R. Prins, J. Phy.Chem. 1981, 85, 2156-2158; b) G. Zhan,
H. C. Zeng, Nat. Commun. 2018, 9, 3778.
[
[
8]
9]
R. Kramer, M. Andre, J. Catal. 1979, 58, 287-295.
[15] a) M. J. Banholzer, J. E. Millstone, L. Qin, C. A. Mirkin, Chem. Soc. Rev.
2008, 37, 885-897; b) S. Guan, O. Donovan-Sheppard, C. Reece, D. J.
Willock, A. J. Wain, G. A. Attard, ACS Catal. 2016, 6, 1822-1832.
[16] a) W. Xie, B. Walkenfort, S. Schlücker, J. Am. Chem. Soc. 2013, 135,
1657-1660; b) E. Cortes, W. Xie, J. Cambiasso, A. S. Jermyn, R.
Sundararaman, P. Narang, S. Schlücker, S. A. Maier, Nat. Commun.
2017, 8, 14880.
a) W. Karim, C. Spreafico, A. Kleibert, J. Gobrecht, J. VandeVondele, Y.
Ekinci, J. A. van Bokhoven, Nature 2017, 541, 68-71; b) G. Kyriakou, M.
B. Boucher, A. D. Jewell, E. A. Lewis, T. J. Lawton, A. E. Baber, H. L.
Tierney, M. Flytzani-Stephanopoulos, E. C. H. Sykes, Science 2012, 335,
1209-1212.
[
10] a) L. R. Merte, G. Peng, R. Bechstein, F. Rieboldt, C. A. Farberow, L. C.
Grabow, W. Kudernatsch, S. Wendt, E. Laegsgaard, M. Mavrikakis, F.
Besenbacher, Science 2012, 336, 889-893; b) G. N. Vayssilov, B. C.
Gates, N. Rosch, Angew. Chem. Int. Ed. 2003, 42, 1391-1394.
[17] a) A. Grirrane, A. Corma, H. García, Science 2008, 322, 1661-1664; b)
J. Zhang, Z. Gao, S. Wang, G. Wang, X. Gao, B. Zhang, S. Xing, S. Zhao,
Y. Qin, Nat. Commun. 2019, 10, 4166; c) L. DeRita, S. Dai, K. Lopez-
Zepeda, N. Pham, G. W. Graham, X. Pan, P. Christopher, J. Am. Chem.
Soc. 2017. 40, 14150-14165.
[
11] a) S. Nie, S. R. Emory, Science 1997, 275, 1102-1106; b) K. Kneipp, Y.
Wang, H. Kneipp, L. T. Perelman, I. Itzkan, R. Dasari, M. S. Feld, Phys.
Rev. Lett. 1997, 78, 1667-1670; c) J. F. Li, Y. F. Huang, Y. Ding, Z. L.
Yang, S. B. Li, X. S. Zhou, F. R. Fan, W. Zhang, Z. Y. Zhou, D. Y. Wu,
B. Ren, Z. L. Wang, Z. Q. Tian, Nature 2010, 464, 392-395.
[18] a) Y. Chen, H. Li, W. Zhao, W. Zhang, J. Li, W. Li, X. Zheng, W. Yan, W.
Zhang, J. Zhu, R. Si, J. Zeng, Nat. Commun. 2019, 10, 1885; b) P. Liu,
Y. Zhao, R. Qin, S. Mo, G. Chen, L. Gu, D. M. Chevrier, P. Zhang, Q.
Guo, D. Zang, B. Wu, G. Fu, N. Zheng, Science 2016, 352, 797-800.
[19] J. Cheng, P. Hu, Angew. Chem. Int. Ed. 2011, 50, 7650-7654.
[20] J. H. Zhong, X. Jin, L. Meng, X. Wang, H. S. Su, Z. L. Yang, C. T. Williams,
B. Ren, Nat. Nanotechnol. 2017, 12, 132-136.
[
12] a) T. Hartman, R. G. Geitenbeek, G. T. Whiting, B. M. Weckhuysen, Nat.
Catal. 2019, 2, 986-996; b) V. Joseph, C. Engelbrekt, J. Zhang, U.
Gernert, J. Ulstrup, J. Kneipp, Angew. Chem. Int. Ed. 2012, 51, 7592-
7596. c) W. Xie, R. Grzeschik, S. Schlücker, Angew. Chem. Int. Ed. 2016,
55, 13729-13733; d) W. Xie, C. Herrmann, K. Kompe, M. Haase, S.
[21] D. H. Kang, M. Trenary, J. Am. Chem. Soc. 2001, 123, 8432-8433.
Schlücker, J. Am. Chem. Soc. 2011, 133, 19302-19305; e) H. Zhang, C.
Wang, H. L. Sun, G. Fu, S. Chen, Y. J. Zhang, B. H. Chen, J. R. Anema,
Z. L. Yang, J. F. Li, Z. Q. Tian, Nat. Commun. 2017, 8, 15447.
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Angewandte Chemie International Edition
10.1002/anie.202000426
COMMUNICATION
COMMUNICATION
Spillover of hydrogen species at Pt-
J. Wei, S.-N. Qin, J.-L. Liu, X.-Y. Ruan,
Z. Guan, H. Yan, D.-Y. Wei, H. Zhang,*
J. Cheng, H. Xu, Z.-Q. Tian, and J.-F.Li*
2
TiO -Au
interfaces
has
been
investigated in situ using SERS with
nanoscale spatial resolution through
the precise fabrication of Au/TiO
2
/Pt
Page 1. – Page 6.
sandwich nanostructures, and the
fundamental mechanism of hydrogen
spillover and its influence on selective
hydrogenation are revealed.
In situ Raman monitoring and
manipulating of interfacial hydrogen
spillover via precise fabrication of
(
(Insert TOC Graphic here))
2
Au/TiO /Pt sandwich structures
This article is protected by copyright. All rights reserved.