In Situ Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy to Unravel Sequential Hydrogenation of Phenylacetylene over Platinum Nanoparticles

Article abstract of DOI:10.1021/acscatal.9b03010

Shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) is quickly developing into a powerful characterization tool in heterogeneous catalysis. In this work, we employ Pt catalysts supported on Au@SiO₂ shell-isolated nanoparticles to study hydrogenation reactions. First, we demonstrate the facile preparation of Pt/Au@SiO₂ and its characterization by using adsorption of CO as probe molecule. Next, we use the adsorption and hydrogenation of phenylacetylene as a model reaction for the interaction of triple bonds and aromatic rings with catalytic Pt surfaces. We show that the applicability of SHINERS is not limited to inherently gaseous compounds, thereby expanding the applicability of the technique to more complex systems. Furthermore, by using nonparticipating side groups as labels, we observe the sequential hydrogenation of phenylacetylene into styrene and ultimately ethylbenzene upon reaction with H₂. Upon the absence of H₂, the reverse reaction takes place with those molecules still adsorbed onto the catalyst surface, which allowed a more detailed understanding of the reaction mechanism and the assignment of Raman peaks. This strengthens the position of SHINERS as an easily applicable surface sensitive technique that can be used to study a wide variety of chemical reactions in the field of heterogeneous catalysis.

Full text of DOI:10.1021/acscatal.9b03010

Subscriber access provided by UNIV OF CAMBRIDGE
Article
In situ Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy to Unravel
Sequential Hydrogenation of Phenylacetylene over Platinum Nanoparticles
Caterina S. Wondergem, Thomas Hartman, and Bert M. Weckhuysen
ACS Catal., Just Accepted Manuscript • DOI: 10.1021/acscatal.9b03010 • Publication Date (Web): 11 Sep 2019
Downloaded from pubs.acs.org on September 18, 2019
Just Accepted
“Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted
online prior to technical editing, formatting for publication and author proofing. The American Chemical
Society provides “Just Accepted” as a service to the research community to expedite the dissemination
of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in
full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully
peer reviewed, but should not be considered the official version of record. They are citable by the
Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore,
the “Just Accepted” Web site may not include all articles that will be published in the journal. After
a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web
site and published as an ASAP article. Note that technical editing may introduce minor changes
to the manuscript text and/or graphics which could affect content, and all legal disclaimers and
ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or
consequences arising from the use of information contained in these “Just Accepted” manuscripts.
is published by the American Chemical Society. 1155 Sixteenth Street N.W.,
Washington, DC 20036
Published by American Chemical Society. Copyright © American Chemical Society.
However, no copyright claim is made to original U.S. Government works, or works
produced by employees of any Commonwealth realm Crown government in the course
of their duties.

Page 1 of 10
ACS Catalysis
1
2
3
4
5
6
In situ Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy
to Unravel Sequential Hydrogenation of Phenylacetylene over
Platinum Nanoparticles
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Caterina S. Wondergem, Thomas Hartman, Bert M. Weckhuysen*
Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg
99, 3584 CG Utrecht, The Netherlands
ABSTRACT: Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy (SHINERS) is quickly developing into a powerful
characterization tool in heterogeneous catalysis. In this work, we employ Pt catalysts supported on Au@SiO
Nanoparticles to study hydrogenation reactions. First, we demonstrate the facile preparation of Pt/Au@SiO
2
Shell-Isolated
and its
2
characterization by using adsorption of CO as probe molecule. Next, we use the adsorption and hydrogenation of
phenylacetylene as a model reaction for the interaction of triple bonds and aromatic rings with catalytic Pt surfaces. We show
that the applicability of SHINERS is not limited to inherently gaseous compounds, thereby expanding the applicability of the
technique to more complex systems. Furthermore, by using unparticipating side groups as labels, we observe the sequential
2 2
hydrogenation of phenylacetylene into styrene and ultimately ethylbenzene upon reaction with H . Upon the absence of H ,
the reverse reaction takes place with those molecules still adsorbed onto the catalyst surface, which allowed more detailed
understanding of the reaction mechanism and the assignment of Raman peaks. This strengthens the position of SHINERS as
an easily applicable surface sensitive technique that can be used to study a wide variety of chemical reactions in the field of
heterogeneous catalysis.
Raman Spectroscopy, Heterogeneous Catalysis, Au Nanoparticles, In Situ SHINERS, Hydrogenation
Introduction.
Understanding
metal-adsorbate
resonance SERS is based on can influence chemical
reactions to be studied by injecting ‘hot electrons’, causing
photocatalytic side-reactions. Furthermore, low stability
interactions is of fundamental importance for rational
1
4,13
catalyst design. Raman spectroscopy offers the ability to
study such interactions, making it a powerful tool in
heterogeneous catalysis research by offering fundamental
insights into structure-performance relationships. These
insights could help in the design of more optimal solid
catalysts for both new and already existing chemical
processes, increasing conversion, activity, and selectivity,
of the Ag and Au NPs limits reaction conditions to be
studied. These challenges can be overcome by using Shell-
Isolated Nanoparticle-Enhanced Raman Spectroscopy
1
4
(SHINERS). For SHINERS, the SERS-active NPs are coated
with a thin layer of dielectric oxide, for example SiO . This
2
thin layer not only increases the thermal and chemical
stability of the SERS-active core, several studies have
2
,3
and reducing waste and greenhouse gases.
showed that the SiO
2
layer also confines hot electrons to the
However, the applicability of Raman spectroscopy to
nanoscale systems is limited due to the poor detection limit,
typically around 1-10 wt% of the probed area. Surface-
1
3,15
core.
They demonstrated this by studying the reduction
4
of 4-nitrothiophenol (4-NTP) to 4-aminothiophenol (4-
ATP) over a Au catalyst. Hot electrons are known to
influence this reaction by catalyzing dimerization to 4,4’-
dimercaptoazobenzene (DMAB).
comprised of SERS-inactive colloidal Au NPs of <5 nm
supported on Au@SiO Shell-Isolated Nanoparticles
(SHINs) prevented the formation of DMAB, thus proving
that hot electrons could not participate in the reaction. A
similar principle where colloidal nanoparticle catalysts
were deposited on SHINs was used by the group of Tian to
Enhanced Raman Spectroscopy (SERS) solves that problem
4
–6
by employing gold and silver nanoparticles (NPs). Au and
Ag NPs of sufficient size (starting at >10 nm; optimum
16–18
Using a catalyst
7
around 100 nm) possess surface plasmons which, when
2
excited with light of the resonant frequency, can create an
electromagnetic field that enhances the Raman scattering of
species on or within several nm of the surface. Using this
principle, in ideal cases SERS has been reported to enhance
1
4
Raman signals with factors of up to 10 , corresponding to
1
9
8
–11
study hydrogenation of 4-NTP and CO adsorption and
even single molecule levels.
For catalysis this means that
2
0
oxidation
on transition metal/Au@SiO
2
SHINs.
SERS has the potential to not only elucidate structure-
performance relationships through studying adsorption of
species of interest on metal surfaces, but also through the
detection of short-lived intermediates or even transition
Furthermore, our group has recently reported that
catalyst/SHIN systems can also be prepared by
impregnation of SHINs with a catalyst precursor followed
21,22
1
2
by in situ reduction.
Subsequently, support effects were
states.
However, the surface plasmons and their
ACS Paragon Plus Environment

ACS Catalysis
Page 2 of 10
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Figure 1. (a) Schematic illustrating the goal of this study, which is to observe the conversion of phenylacetylene to styrene and
ethylbenzene over a Pt hydrogenation catalyst placed inside the enhanced electromagnetic field of a SERS-active Au@SiO
Isolated Nanoparticle (SHIN). (b) Schematic visualization of the Pt/Au@SiO cat/SHIN preparation. (c) Transmission electron
microscopy (TEM) images of the Au core nanoparticles, and (d) Au@SiO SHINs, and (e) of a Pt/Au@SiO catalyst/SHIN. (f) Size
distributions based on TEM measurements. The Au core (top, yellow) NPs have a mean diameter of 101 nm and are coated with a 2
nm layer of SiO (middle, green). Pt NPs (bottom, red) are ~3.8 nm in diameter. (g) Elemental map of (e) confirming the presence of
Pt (red) on top of the Au@SiO (yellow, green, respectively) SHINs. Note that the Pt/Au@SiO TEM samples were prepared after in
situ SHINERS experiments by redispersion from the Si wafer and transfer to a TEM grid. Therefore, the aggregation state and
dispersion of Pt NPs over the Au@SiO SHINs is not a representative image of their dispersion during in situ experiments.
studied by investigating CO hydrogenation over Ru and Rh styrene and finally ethylbenzene, on the surface of a
catalysts supported on Au@SiO and Au@TiO SHINs. Pt/Au@SiO catalyst, as shown in Figure 1a.
2
Shell-
2
2
2
2
2
2
2
2
2
2
In this study, we will extend the applicability of SHINERS
to reactions beyond those involving 4-NTP and simple
gases, such as CO. For the first time, we report an in situ
SHINERS study of sequential hydrogenation reactions of
organic molecules, more specifically phenylacetylene to
Normally, this chemical reaction is carried out in the
liquid phase, at slightly elevated temperatures and
23
pressures.
Furthermore, often
a
Lindlar catalyst
composed of Pd poisoned with S and Pb is used to
selectively produce alkenes and prevent further
2
4
hydrogenation to alkanes. However, we will prepare
ACS Paragon Plus Environment

Page 3 of 10
ACS Catalysis
2
SHINs and deposit catalytically active Pt catalysts connected to an Andor EMCCD detector equipped with a
Au@SiO
on the surface by wet impregnation and in situ reduction as
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
1200 l/mm grating.
2
1
reported by Hartman et al. We will show that SHINERS is
a suitable technique to study hydrogenation reactions of
alkynes and alkenes, and that aromatic side groups can be
used as spectroscopic tags to monitor the reaction.
Furthermore, by using phenylacetylene vapor saturated in
CO adsorption experiments. After in situ reduction, 10
mL/min CO and 40 mL/min Ar were introduced into the
Linkam Cell at 150 °C. Adsorption of CO was monitored with
in situ SHINERS on a Renishaw inVia confocal Raman
microscope using a 20x objective (NA = 0.4), 1200 l/mm
grating, 0.12-1.96 mW laser intensity with 785 nm laser
excitation.
2
N , we show that the application of SHINERS to
heterogeneous catalysis is not limited to intrinsically
gaseous compounds.
Phenylacetylene
adsorption
experiments.
N
2
Experimental Section
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
saturated with phenylacetylene was introduced into the
Linkam Cell. Adsorption was studied at 25, 40, 60 and 80 °C
for 30 min each and was monitored with in situ SHINERS on
a Renishaw inVia confocal Raman microscope using a 20x
objective (NA = 0.4), 1200 l/mm grating, 0.12-1.96 mW
laser intensity with 785 nm laser excitation.
Preparation of Au@SiO
Au@SiO
SHINs is described in detail elsewhere.25 In short,
gold seeds were synthesized using the Turkevich method
to obtain Au seeds of approximately 17 nm in MilliPore
water (MQ; resistivity 18.2 MΩ·cm) (HAuCl × 3H O 99.99%
2
SHINs. The preparation of
2
2
6
4
2
obtained from Alfa Aesar; sodium tricitrate dihydrate, 99%,
Sigma Aldrich). NPs were grown to a size of approximately
Phenylacetylene
Phenylacetylene hydrogenation was studied by flowing H
over the catalyst at 60 °C. The feed consisted of a 1:1
mixture of with either saturated with
phenylacetylene, or with Ar. Dehydrogenation conditions
were achieved by flowing only Ar. The total flow was always
hydrogenation
experiments.
2
1
00 nm using NH
mild reducing agent. Subsequent SiO
through the APTMS (99%, Sigma Aldrich)/sodium silicate
2
OH × HCl (99.995%, Sigma Aldrich) as a
27
2
growth was realized
H
2
N
2
25
(
2
27%, Sigma Aldrich) method to yield Au@SiO SHINs.
Successful synthesis of these particles was confirmed as per
the characterization data presented in Figure 1c,d,f and the
Supporting Info Figures S1-3.
5
0 mL/min. Hydrogenation was monitored using in situ
SHINERS on a Renishaw inVia confocal Raman microscope
using a 20x objective, 1200 l/mm grating, 0.12-1.96 mW
laser intensity with 785 nm laser excitation.
Preparation of Pt/Au@SiO
PtCl (99.995%, Sigma Aldrich) solution was mixed with
0.5 mL Au@SiO SHINs. After mixing and equilibrating for
2
SHINs. 50 μL of a 10 mM
H
2
6
Results
2
Characterization of Pt/Au@SiO
Figure 1b shows a schematic representation of the
preparation of Pt/Au@SiO . The transmission electron
microscopy (TEM) images of the corresponding Au NPs at
the top, the Au@SiO shell-isolated nanoparticles (SHINs) in
the middle and the Pt/Au@SiO cat/SHINs at the bottom are
2
catalyst/SHINs.
~30 min, 15 μL of the mixture was dropcast on a Si wafer
and was vacuum dried. The sample was cleaned in Ossila
E511 UV-Ozone Cleaner for 15 min before in situ SHINERS
experiments. The sample was placed in a Linkam Cell and Pt
2
2
2
was reduced in situ at 150 °C under 50% H flow in Ar for 1
2
h, while monitoring the process with SHINERS on a
Renishaw inVia confocal Raman microscope using a 20x
objective (NA = 0.4), 1200 l/mm grating, 0.12-1.96 mW
laser intensity with 785 nm laser excitation.
shown in Figure 1c-e, respectively, along with the
accompanying particle size distributions in Figure 1f. The
101 nm diameter of the Au core lies close to the reported
7
optimum for enhanced Raman scattering , whereas the
2
Characterization. Au and Au@SiO NP size and LSPR
2
ultrathin SiO coating of 2.0±0.5 nm is a good trade-off
were investigated with UV-Vis absorption spectroscopy on
a Varian Cary 50 UV-Visible spectrophotometer in quartz
cuvettes with an optical path length of 10.00 mm. Au and
between minimizing the loss in signal intensity and
19,25,28
obtaining a pinhole-free coating.
Small nanostructures
SHINs, which were
can be observed covering the Au@SiO
2
2
Au@SiO NP size and layer thickness were investigated on
confirmed to consist of Pt by the Energy Dispersive X-ray
Spectroscopy (EDX) map in Figure 1g. Particle size analysis
of 740 Pt NPs gives an average size of 3.8 nm and a standard
deviation of 1.1 nm. Taking into account the thickness of the
a FEI Tecnai 12 and FEI Tecnai 20 transmission electron
microscope (TEM), operating at 120 keV and 200 keV,
respectively. Samples were prepared by drying 15 μL of the
dispersions onto Formvar/carbon-coated 300 mesh copper
SiO layer, this means that on average the outer surface of
2
TEM grids (Van Loenen Instruments). The Pt/Au@SiO
catalyst/SHINs were investigated with elemental analysis
using High-Angle-Annular Dark Field Scanning
2
the Pt NPs is about 5.5 nm away from the Au core. As the
SERS effect is a very local effect with most intense
enhancement factors arising within ~5 nm of the Au NP
4
Transmission Electron Microscopy (HAADF-STEM) and
Energy Dispersive X-ray Spectroscopy (EDX) on a FEI Talos
F200 electron microscope operating at 200 keV. Samples
were prepared by redispersing in situ reduced samples in
isopropanol and subsequent transfer to Formvar/carbon-
coated 300 mesh copper TEM grids.
surface , this potentially means that we cannot observe
processes occurring on the entire Pt NP surface. In order to
test this, we performed CO adsorption experiments on the
Pt/Au@SiO2 samples. First, samples were cleaned with
UV/Ozone and then reduced in situ in a Linkam Cell at 150
°C for 1 h in a 1:1 mixture of H and Ar. The Raman spectra
2
were recorded using a 785 nm excitation source, which is
known to give limited potential plasmonic side reactions in
Raman spectroscopy of reference compounds. Raman
spectra of pure phenylacetylene, styrene and ethylbenzene
were measured in a quartz cuvette with an optical path
length of 10.00 mm using an Avantes Raman probe in
combination with a 532 nm Cobalt laser set to 51 mW
combination with Au nanoparticles (NPs) under the applied
12, 22
conditions.
Figure 2a shows the SHINER spectra during
reduction. At the start of the experiment, two broad bands
-1
can be observed, namely one around 330 cm for Pt-Cl
ACS Paragon Plus Environment

ACS Catalysis
Page 4 of 10
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
-
1
-1
Figure 2. (a) In situ SHINER spectra of reduction of Pt
cm originating from the Si wafer used to support the Pt/Au@SiO
1
x
Cl
y
(330 cm ) and Pt
x z
O (560 cm ) to metallic Pt. Note the sharp peak at 520
-1
2
catalyst/SHINs. (b, c) In situ SHINER spectra of CO adsorption at
-1
-1
-1
-1
50 °C. Both peaks assigned to CO in a bridge (b, 430 cm ; c, 2010 cm ) and linear (b, 505 cm ; c, 2070 cm ) configuration on Pt
were observed. (d-g) Phenylacetylene adsorption on activated Pt/Au@SiO catalyst/SHINs. (d) Metal-adsorbate stretching region
where a peak assigned to Pt-C stretching can be observed at different temperatures. (e) Peak height for the Pt-C stretching vibration
showing an optimum at 60 °C. (f) C≡C stretching region. The reference spectrum of phenylacetylene exhibits an intense peak
originating from free C≡C-H at 2105 cm , whereas phenylacetylene chemisorbed on Pt at 60 °C shows three peaks at 1960, 2010
and 2190 cm , indicated with asterisks. (g) Schematic of phenylacetylene chemisorption on Pt NPs through σ and π interactions.
2
-1
-1
-1
stretching vibrations from the platinum precursor, and one
cm . Characteristic peaks for these two configurations can
also be found in the high wavenumber region, looking at the
C-O stretching vibration. Again, we observe a vibration
-1
around 560 cm , which does not originate from Pt-Cl
2
9
vibrations. During UV-Ozone treatment, the platinum
chloride precursor becomes partially oxidized, resulting in
the appearance of Pt-O stretching vibrations of amorphous
-1
associated with bridged CO as a shoulder at 2010 cm ,
-1
while at 2070 cm we can see C-O stretching of CO adsorbed
in a linear configuration. These experiments show that: (1)
The Pt NPs are within the range for signal enhancement
from the SERS effect; (2) We can observe interactions of
adsorbates with multiple sites of the Pt catalyst, and; (3) we
have sufficient accessible Pt surface that can be used to
study heterogeneous catalytic reactions. Finally, as no shift
in the stretching vibrations or bands corresponding to CO
3
0–32
platinum oxide.
Upon introducing reducing conditions,
the bands start to decrease in intensity and after an hour
they are completely gone, indicating the formation of
33
(
Raman-inactive) metallic Pt. Subsequently, the in situ cell
was flushed with Ar and CO was introduced at 150 °C.
Figure 2b and 2c show the low and high wavenumber region
of the SHINER spectra obtained during in situ CO
adsorption. The low wavenumber region is known to show
bands arising from metal-adsorbate stretching vibrations.
Indeed, when we compare our CO adsorption spectra to
those in literature, we can see that we observe similar peaks
on Au were observed, we can state that our SiO
2
layer is
pinhole-free and our SHINs are stable (for additional tests,
1
4,35
see Figure S3-S5).
Phenylacetylene
phenylacetylene on Pt/Au@SiO
investigated at various temperatures to determine the
optimum conditions for hydrogenation reactions. N was
flowed through a bubbler filled with phenylacetylene to
adsorption.
Adsorption
catalyst/SHINs was
of
2
0,21,34
corresponding to CO adsorption on a Pt surface.
In
2
particular, we observe two different vibrations, one due to
CO adsorbed on Pt in a bridge configuration at 430 cm and
one corresponding to CO adsorbed in a linear fashion at 505
-
1
2
ACS Paragon Plus Environment

Page 5 of 10
ACS Catalysis
obtain a saturated gas feed that was led over the catalyst
placed in a Linkam Cell (See Figure S6 for the experimental
setup). Figure 2d and e report on the Pt-C vibration
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
-1
observed at 405 cm as we regard it as a measure of the
3
6,37
amount of phenylacetylene present on the Pt surface.
Therefore, phenylacetylene hydrogenation will be studied
at the temperature for which we find an optimum in
adsorption. Although no internal standard is present, by
examining and focusing on the same spot on the sample,
peak intensities can be reliably compared to one another
within one experiment. Fitting and integration of the peak
originating from the Pt-C stretching vibration in Figure 2d
shows that an optimum in peak height exists at 60 °C, as
displayed in Figure 2e. Figure 2f shows the C≡C stretching
region where for pure phenylacetylene we expect to see one
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
-1
sharp peak at 2105 cm . However, we observe that upon
adsorption on the Pt catalyst, it splits into two distinct peaks
-1
at 2190 and 2010 cm with the latter possessing a shoulder
-1
around 1960 cm . This indicates that adsorption only takes
place through the acetylene group, and not through the
aromatic ring. These observations are in line with
adsorption reported of phenylacetylene and other alkynes
3
8–46
on different transition metals
and are attributed to
chemisorption; σ-bonding, and σπ-complexation of a weak
nature with different sites on the Pt surface, based on the
relatively small shift in the C≡C vibrations compared to free
43,45
(
phenyl)acetylene.
Furthermore, surface science
experiments have shown that the aromatic ring in
substituted benzenes orients itself away from the surface
and is therefore not involved in adsorption.43,46
Phenylacetylene adsorption SHINERS experiments were
also performed on Au NPs and Au@SiO
2
SHINs for
comparison (Figure S7). A discussion of these spectra
shown in Figure S7 can be found in the Supporting
Information.
ACS Paragon Plus Environment

ACS Catalysis Page 6 of 10
2
shows After 30 min, the Ar flow was switched to H and
Phenylacetylene hydrogenation. Figure
3
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
SHINER spectra from hydrogenation of phenylacetylene to
styrene and ultimately ethylbenzene at 60 °C with time-on-
immediately a decrease in C≡C stretching was observed,
whereas a similar decrease was not observed in the other
spectral regions. Only after ~60 min of simultaneous
phenylacetylene adsorption and hydrogenation did we
observe a decrease, alongside an even further decrease in
C≡C stretching peak intensity. Additionally, we observe the
appearance of two new peaks in the C=C region.
Comparison to reference spectra shown in Figures 3e and
stream (TOS) under different conditions. First, N
2
saturated
with phenylacetylene and Ar were led over the catalyst in a
1
:1 ratio. As expected based on the adsorption experiments,
-1
we observe a peak attributed to Pt-C stretching at 405 cm
in Figure 3a and three peaks in the C≡C region in Figure 3d.
Furthermore, Figure 3b shows peaks originating from ring
breathing vibrations of a monosubstituted benzene around
-1
S8 shows that the peak at ~1634 cm can be attributed to
C=C stretching originating from the ethylene group in
-
1
-1
1
000 cm and 1030 cm and in Figure 3c we observe a peak
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
-1
-1
from aromatic C=C stretching at 1592 cm . All of the peaks
originating from aromatic ring vibrations appear
unperturbed compared to the reference spectra in Figure 3f
styrene, whereas the peak at ~1571 cm does not match
any of the peaks in the reference spectra. However, Mrozek
and Weaver have reported similar peaks for π-bound
36
31
and literature. This indicates a lack of interaction between
ethylene on Pt electrodes studied with SERS. Monitoring
the phenyl ring and the Pt surface, and further supports
adsorption solely through C≡C as previously discussed.
the presence of this band over the experiment as displayed
in Figure S9 shows that it is only present alongside the 1634
2
Figure 3. (a-d) Hydrogenation of phenylacetylene over Pt/Au@SiO catalyst/SHINs at 60 °C with time-on-stream (TOS). (a) Pt-C
stretching region. Upon hydrogenation of phenylacetylene, the peak attributed to Pt-C stretching decreases slightly and then remains
constant. (b) Spectral region showing ring vibrations. Upon hydrogenation a shift to higher frequencies is observed, indicating
hydrogenation occurs. (c) C=C stretching region indicating C=C stretching from the phenyl group. Two additional peaks attributed
to C=C stretching can be observed during hydrogenation; at higher frequencies due to C=C stretching of the ethylene group present
in styrene, and at lower frequencies due to π-bound ethylene from styrene. (d) C≡C stretching region which shows complete
disappearance of alkyne vibrations over the course of hydrogenation. (e) Reference spectra of phenylacetylene (PA, red), styrene
(Sty, blue) and ethylbenzene (EB, green) in which ring breathing vibrations and the aromatic C=C stretching vibrations used for
further analysis are indicated. (f) Tracking the peak position of the ring breathing vibration with TOS shows a clear shift towards
the reference position of ethylbenzene (green dashed line). Gas feed composition is indicated at the top of the graph. (g) Ratio
I
1592/I999 with TOS compared to reference values of phenylacetylene (red), styrene (blue) and ethylbenzene (green) indicates the
formation of ethylbenzene.
ACS Paragon Plus Environment

Page 7 of 10
ACS Catalysis
cm-1 peak from the ethylene group in styrene, thereby
indicating that the peak at 1571 cm can be attributed to π-
bound styrene on Pt. Subsequently, we turned off the
phenylacetylene flow and continued the experiments with a
vibration at 999 cm (I999) differs amongst phenylacetylene,
styrene, and ethylbenzene. Upon fitting of the experimental
-1
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
-1
4
7
spectra , the ratio I1592/I999 was compared to those of the
reference compounds and again a trend was observed that
indicates the formation of ethylbenzene, as illustrated in
Figure 3g. Interestingly, switching back to pure Ar flow
leads to an upwards shift of the ratio I1592/I999, back to the
values of styrene and phenylacetylene (Figure S11).
gas feed composed of H
2
and Ar to ensure full
hydrogenation of all adsorbed species. A further decrease in
peaks originating from C≡C stretching vibrations is
observed, alongside the disappearance of those
corresponding to ethylene. The aromatic C=C stretching
To
determine
whether
we
are
witnessing
-1
vibrations at 1592 cm remain present, although with very
little intensity. Furthermore, both Pt-C vibrations and ring
breathing vibrations remain present, but whereas the Pt-C
dehydrogenation or simply readsorption of residual
phenylacetylene, cycles of hydrogenation-dehydrogenation
experiments were performed, as reported in Figure 4.
Figure 4a shows the ratio I1592/I999 with TOS under different
gas feed compositions: pure phenylacetylene in N
and H , Ar and H , and pure Ar as indicated above the graph.
Upon introduction of hydrogen, the ratio I1592/I999 decreases
to indicate ethylbenzene formation. However, as soon as H
is removed from the gas feed and we flow pure Ar, the ratio
starts to increase again, away from the ethylbenzene
reference value. This trend can be observed throughout the
entire experiment, and is also reflected in the ring breathing
peak position (Figure S12). After leaving the cell under
continuous Ar flow for three days, the ratio I1592/I999 reaches
the reference values for styrene and phenylacetylene. Over
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
-1
stretching vibrations remains at 405 cm , the ring
breathing vibrations exhibit a shift to higher frequencies.
Based on the reference spectra in Figure 3e and S8 this shift
indicates a decrease in conjugation. Tracking the position of
2
(PA), PA
2
2
-1
the ring breathing vibration at 999 cm by deconvolution of
2
4
7
the spectra (See Figure S10) and subsequent comparison
with reference spectra as displayed in Figure 3f show that
the peak position moves in the direction of the reference
value for ethylbenzene under hydrogenation conditions.
Further inspection of the reference spectra also shows that
the ratio of the peak intensity of the aromatic C=C stretching
vibration (I1592) to the peak intensity of the ring breathing
Figure 4. (a) Monitoring the ratio I1592/I999 with TOS in hydrogen-rich and hydrogen-poor gas feeds compared to the reference
compounds phenylacetylene (PA, red), styrene (Sty, blue) and ethylbenzene (EB, green). The gas feed composition is indicated
above the figure. In hydrogen-rich environments, a clear shift towards the reference value for ethylbenzene is observed, whereas
the reverse shift occurs in the absence of hydrogen. (b) Spectra of phenylacetylene adsorption at the start of the experiment (Ads),
after hydrogenation (TOS = 860 min) and after 3 days under pure Ar flow. (c) Scheme of phenylacetylene hydrogenation and
dehydrogenation including all observed species. Note that upon changing the gas feed composition, and especially when
introducing H
2 2
, the ratio I1592/I999 tends to drop. We attribute this to the high heat capacity of H and the fluctuations in conditions
this brings about before equilibration.
ACS Paragon Plus Environment

ACS Catalysis
Page 8 of 10
the course of this experiment, the intensity of the Pt-C generally applicable characterization method in the field of
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
stretching vibration was monitored for changes in the
amount of adsorbates, presented in Figure S13. Inspection
of this intensity shows that after equilibration the Pt-C peak
height remains at constant values, excluding the possibility
for readsorption of residual phenylacetylene which would
be reflected in an increase in peak height. Figure 4b shows
spectra at the start of the experiment, when
phenylacetylene was adsorbed, at the end of the
hydrogenation experiments at TOS = 860 min and after
keeping the sample under constant Ar flow for 3 days. Ring
breathing, C=C and C≡C stretching vibrations indicated in
the figure show that first, the aromatic ring stays intact,
second, that no peaks ascribed to styrene are observed (see
also Figure S9) and third, C≡C stretching vibrations
disappear upon hydrogenation but return in the absence of
hydrogen, showing that the ethylbenzene that remains on
the catalyst surface after hydrogenation is dehydrogenated
back to phenylacetylene.
heterogeneous catalysis. By employing a setup and method
that allows the reverse reaction to be studied, we were able
to give more detailed Raman peak assignment and gain
understanding of the reaction mechanism. Furthermore, we
show that spectator or unreacting side groups can be used
as internal reference, opening up the possibility to study
reactions of chemical groups with an inherent low Raman
cross-section and reactions of complicated molecules over
heterogeneous catalysts using in situ SHINERS.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
ASSOCIATED CONTENT
Supporting Information.
The Supporting Information is available free of charge via the
Internet at http://pubs.acs.org.
UV-Vis spectroscopy of Au seeds, Au NPs and
Au@SiO
seeds, Au NPs, Au@SiO
of Pt/Au@SiO catalyst/SHINs after reaction; pinhole
SERS-activity test for Au@SiO SHINs;
2
SHINs dispersions; TEM analysis data of Au
2
SHINs and additional images
2
&
2
Based on the spectral observations we made, we propose
that in our experiments phenylacetylene hydrogenation
occurs as follows: Phenylacetylene is adsorbed on the Pt
Experimental setup for in situ SHINERS experiments;
Additional SHINER spectra; Full reference spectra of
phenylacetylene,
styrene
and
ethylbenzene;
-1
surface, giving rise to a Pt-C stretch at 405 cm and a
monitoring presence of peaks related to styrene;
Fitting of spectra; Monitoring Pt-C stretching peak
intensity; Tracking ring breathing peak positions
with TOS.
splitting of the C≡C band into three bands at 1960, 2010 and
-1
2
190 cm due to chemisorption (σ-bonding and weak σπ-
complexation) and physisorption. The absence of free
≡C -H stretching vibrations and lack of distortion in ring
C
2
1
vibrations confirm adsorption takes place solely through
the triple bond. Upon hydrogenation, we observe styrene
AUTHOR INFORMATION
-1
both in a linear, σ-bound fashion at 1621 cm and π-bound
-1
through its ethylene group at 1571 cm , depending on
Corresponding Author
b.m.weckhuysen@uu.nl
1 2
whether a hydrogen is inserted first in C or C , respectively.
*
Upon complete disappearance of both the C≡C stretching
vibrations and vibrations ascribed to styrene, ethylbenzene
is observed. The presence of the Pt-C stretching peak allows
us to assign this peak to linear σ-bonding of the terminal
Author Contributions
The manuscript was written through contributions of all
authors. All authors have given approval to the final version of
the manuscript.
alkyl C
presented in Figure 4c. This is in line with the observation
of lack of π–bonding styrene species upon
1
atom to the Pt surface, resulting in the scheme
Funding Sources
a
This work is financially supported by a Technology Area (TA)
grant from the Netherlands Organization of Scientific
Research (NWO), Albemarle Catalysts, BASF, and TNO.
dehydrogenation, as logically linearly bound styrene should
be formed. Furthermore, after dehydrogenation the peak
ratios of the different C≡C stretching vibrations differ from
those observed during adsorption. The peaks at 2010 and
ACKNOWLEDGMENT
We acknowledge Hans Meeldijk for (HAADF)-STEM and EDX
measurements.
-
1
1
960 cm we attribute therefore to chemisorbed species:
-1
2 1
The most intense peak at 2010 cm we assign to C ≡C -Pt σ-
-1
bonding, and its shoulder at 1960 cm to the weak σπ-
complexation of the acetylene group with Pt, as π –
interaction of conjugated bonds parallel to the surface is
often reported to result in a redshift in wavenumber.
Finally, we propose the peak at 2190 cm arises from
adsorption at a less stable configuration or site, based on
the low intensity of the peak observed upon
dehydrogenation.
REFERENCES
31,48,49
(1)
Bell, A. T. The Impact of Nanoscience on Heterogeneous
Catalysis. Science 2003, 299, 1688–1691.
-1
(
(
2)
3)
2
Lee, E. L.; Wachs, I. E. In Situ Raman Spectroscopy of SiO -
4
0
18
Supported Transition Metal Oxide Catalysts: An Isotopic O-
1
6
O Exchange Study. J. Phys. Chem. C. 2008, 112, 6487–6498.
Lee, E. L.; Wachs, I. E. In Situ Spectroscopic Investigation of
the Molecular and Electronic Structures of SiO Supported
2
Conclusions. Herein, we showed that in situ SHINERS
allows for identification of catalyst-adsorbate interactions
on the nanoscale, using the sequential gas-phase
hydrogenation of phenylacetylene to styrene and ultimately
Surface Metal Oxides. J. Phys. Chem. C 2007, 111, 14410–
14425.
(4)
Schlücker, S. Surface-Enhanced Raman Spectroscopy:
Concepts and Chemical Applications. Angew. Chemie - Int. Ed.
2014, 53, 4756–4795.
2
ethylbenzene over Pt/Au@SiO catalyst/SHINs as a model
(
5)
Fleischmann, M.; Hendra, P. J.; McQuillan, A. J. Raman Spectra
reaction. This work demonstrates that in situ SHINERS can
be used to monitor hydrogenation reactions while they
occur on the surface of the catalyst, proving its value as a
of Pyridine Adsorbed at a Silver Electrode. Chem. Phys. Lett.
1974, 26, 163–166.
(6)
Hartman, T.; Wondergem, C. S.; Kumar, N.; Van Den Berg, A.;
ACS Paragon Plus Environment

Page 9 of 10
ACS Catalysis
Weckhuysen, B. M. Surface- and Tip-Enhanced Raman
Spectroscopy in Catalysis. J. Phys. Chem. Lett. 2016, 7, 1570–
584.
Fang, P.-P.; Li, J.-F.; Yang, Z.-L.; Li, L.-M.; Ren, B.; Tian, Z.-Q.
Optimization of SERS Activities of Gold Nanoparticles and
Gold-Core-Palladium-Shell Nanoparticles by Controlling Size
and Shell Thickness. J. Raman Spectrosc. 2008, 39, 1679–
Phenylacetylene Hydrogenation with Pd, Pt and Pd-Pt Alloy
Catalysts Dispersed on Amorphous Supports: Effect of Pt/Pd
Ratio on Catalytic Activity and Selectivity. J. Mol. Catal. 1984,
26, 375–384.
Lindlar, H.; Dubuis, R. Palladium Catalyst for Partial
Reduction of Acetylenes. Org. Synth. 1966, 46, 89–92.
Li, J. F.; Tian, X. D.; Li, S. B.; Anema, J. R.; Yang, Z. L.; Ding, Y.;
Wu, Y. F.; Zeng, Y. M.; Chen, Q. Z.; Ren, B.; Wang, Z. L.; Tian, Z.
Q. Surface Analysis Using Shell-Isolated Nanoparticle-
Enhanced Raman Spectroscopy. Nat. Protoc. 2013, 8, 52–65.
Turkevich, J.; Stevenson, P. C. A Study of the Nucleation and
Growth Processes in the Synthesis of Colloidal Gold. Discuss.
Faraday Soc. 1951, 11, 55–75.
Cao, L.; Zhu, T.; Liu, Z. Formation Mechanism of Nonspherical
Gold Nanoparticles during Seeding Growth: Roles of Anion
Adsorption and Reduction Rate. J. Colloid Interface Sci. 2006,
293, 69–76.
Kobayashi, Y.; Correa-Duarte, M. A.; Liz-Marzán, L. M. Sol-Gel
Processing of Silica-Coated Gold Nanoparticles. Langmuir
2001, 17, 6375–6379.
1
2
1
(
7)
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
(24)
(25)
1
687.
(
(
8)
9)
Zhang, R.; Zhang, Y.; Dong, Z. C.; Jiang, S.; Zhang, C.; Chen, L. G.;
Zhang, L.; Liao, Y.; Aizpurua, J.; Luo, Y.; Yang, J. L.; Hou, J. G.
Chemical Mapping of a Single Molecule by Plasmon-Enhanced
Raman Scattering. Nature 2013, 498, 82–86.
Sigle, D. O.; Kasera, S.; Herrmann, L. O.; Palma, A.; De Nijs, B.;
Benz, F.; Mahajan, S.; Baumberg, J. J.; Scherman, O. A.
Observing Single Molecules Complexing with Cucurbit[7]Uril
through Nanogap Surface-Enhanced Raman Spectroscopy. J.
Phys. Chem. Lett. 2016, 7, 704–710.
Etchegoin, P. G.; Le Ru, E. C. A Perspective on Single Molecule
SERS: Current Status and Future Challenges. Phys. Chem.
Chem. Phys. 2008, 10, 6079.
Pozzi, E. A.; Zrimsek, A. B.; Lethiec, C. M.; Schatz, G. C.; Hersam,
M. C.; Van Duyne, R. P. Evaluating Single-Molecule Stokes and
Anti-Stokes SERS for Nanoscale Thermometry. J. Phys. Chem.
C 2015, 119, 21116–21124.
(26)
(27)
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
(
(
10)
11)
(28)
(29)
Ren, B.; Yao, J. L.; Li, X. Q.; Cai, W. B.; Mao, B. W.; Tian, Z. Q. A
New Progress in Surface Raman Spectroscopy of Platinum
Electrode Surfaces. Internet J. Vib. Spectrosc. 1996,
[www.ijvs.com] 1, 7.
Graham, G. W.; Weber, W. H.; McBride, J. R.; Peters, C. R.
Raman Investigation of Simple and Complex Oxides of
Platinum. J. Raman Spectrosc. 1991, 22, 1–9.
(
12)
Van Schrojenstein Lantman, E. M.; De Peinder, P.; Mank, A. J.
G.; Weckhuysen, B. M. Separation of Time-Resolved
Phenomena in Surface- Enhanced Raman Scattering of the
(30)
(31)
Photocatalytic
Reduction
of
p-Nitrothiophenol.
Mrozek, M. F.; Weaver, M. J. Periodic Trends in Electrode-
Chemisorbate Bonding: Ethylene on Platinum-Group and
Gold Electrodes as Probed by Surface-Enhanced Raman
Spectroscopy. J. Phys. Chem. B 2001, 105, 8931–8937.
Huang, Y. F.; Kooyman, P. J.; Koper, M. T. M. Intermediate
Stages of Electrochemical Oxidation of Single-Crystalline
Platinum Revealed by in Situ Raman Spectroscopy. Nat.
Commun. 2016, 7, 1–7.
Lin, W.; Herzing, A. A.; Kiely, C. J.; Wachs, I. E. Probing Metal-
Support Interactions under Oxidizing and Reducing
Conditions: In Situ Raman and Infrared Spectroscopic and
Scanning Transmission Electron Microscopic-X-Ray Energy-
Dispersive Spectroscopic Investigation of Supported
Platinum Catalysts. J. Am. Chem. Soc. 2008, 112, 5942–5951.
Williams, C. T.; Tolia, A. A.; Weaver, M. J.; Takoudis, C. G.
Surface-Enhanced Raman Spectroscopy as an In Situ Real-
Time Probe of No Reduction over Rhodium at High Gas
Pressures. Chem. Eng. Sci. 1996, 51, 1673–1682.
ChemPhysChem 2015, 16, 547–554.
Zhang, K.; Xu, N.; Jia, M.; Li, R.; Huang, M. In Situ Detection of
Hot-Electron-Induced Photocatalytic Reduction Using
(
(
13)
14)
Au@Ag, Au@Ag
2
S, and Au@SiO
2
Core-Shell Nanoparticles. J.
(32)
(33)
Appl. Phys. 2019, 125, 183101.
Li, J. F.; Huang, Y. F.; Ding, Y.; Yang, Z. L.; Li, S. B.; Zhou, X. S.;
Fan, F. R.; Zhang, W.; Zhou, Z. Y.; Wu, D. Y.; Ren, B.; Wang, Z. L.;
Tian, Z. Q. Shell-Isolated Nanoparticle-Enhanced Raman
Spectroscopy. Nature 2010, 464, 392–395.
Xie, W.; Walkenfort, B.; Schlücker, S. Label-Free SERS
Monitoring of Chemical Reactions Catalyzed by Small Gold
Nanoparticles Using 3D Plasmonic Superstructures. J. Am.
Chem. Soc. 2012, 135, 1657-1660.
Van Schrojenstein Lantman, E. M.; Gijzeman, O. L. J.; Mank, A.
J. G.; Weckhuysen, B. M. Investigation of the Kinetics of a
Surface Photocatalytic Reaction in Two Dimensions with
Surface-Enhanced Raman Scattering. ChemCatChem 2014, 6,
(15)
(16)
(34)
(35)
3
342–3346.
Li, J. F.; Anema, J. R.; Wandlowski, T.; Tian, Z. Q. Dielectric Shell
Isolated and Graphene Shell Isolated Nanoparticle Enhanced
Raman Spectroscopies and Their Applications. Chem. Soc. Rev.
2015, 44, 8399–8409.
(17)
Liu, Y.; Zhao, Y.; Zhang, L.; Yan, Y.; Jiang, Y. Controllable
Plasmon-Induced Catalytic Reaction by Surface-Enhanced
and Tip-Enhanced Raman Spectroscopy. Spectrochim. Acta -
Part A Mol. Biomol. Spectrosc. 2019, 219, 539–546.
Kumar, N.; Wondergem, C. S.; Wain, A. J.; Weckhuysen, B. M. In
Situ Nanoscale Investigation of Catalytic Reactions in the
Liquid Phase Using Zirconia-Protected Tip-Enhanced Raman
Spectroscopy Probes. J. Phys. Chem. Lett. 2019, 10, 1669–
(36)
(37)
Socrates, G. Infrared and Raman Characteristic Group
rd
(
18)
Frequencies, 3 ed.; John Wiley & Sons Ltd: Chichester,
England, 2001.
Shen, W.; Lin, X.; Jiang, C.; Li, C.; Lin, H.; Huang, J.; Wang, S.; Liu,
G.; Yan, X.; Zhong, Q.; Ren, B. Reliable Quantitative SERS
Analysis Facilitated by Core-Shell Nanoparticles with
Embedded Internal Standards. Angew. Chemie - Int. Ed. 2015,
54, 7308–7312.
Ando, J.; Asanuma, M.; Dodo, K.; Yamakoshi, H.; Kawata, S.;
Fujita, K.; Sodeoka, M. Alkyne-Tag SERS Screening and
Identification of Small-Molecule-Binding Sites in Protein. J.
Am. Chem. Soc. 2016, 138, 13901–13910.
Weckhuysen, B. M. Catalysts Live and up Close. Nature 2006,
439, 548.
Jang, Y. H.; Hwang, S.; Oh, J. J.; Joo, S. W. Adsorption Change of
Cyclohexyl Acetylene on Gold Nanoparticle Surfaces. Vib.
Spectrosc. 2009, 51, 193–198.
Joo, S. W.; Kim, K. Adsorption of Phenylacetylene on Gold
Nanoparticle Surfaces Investigated by Surface-Enhanced
Raman Scattering. J. Raman Spectrosc. 2004, 35, 549–554.
Kennedy, D. C.; McKay, C. S.; Tay, L.; Rouleau, Y.; Pezacki, J. P.
Carbon-Bonded Silver Nanoparticles: Alkyne-Functionalized
Ligands for SERS Imaging of Mammalian Cells. Chem.
Commun. 2011, 47, 3156–3158.
1
675.
(19)
(20)
Zhang, H.; Zhang, X. G.; Wei, J.; Wang, C.; Chen, S.; Sun, H. L.;
Wang, Y. H.; Chen, B. H.; Yang, Z. L.; Wu, D. Y.; Li, J. F.; Tian, Z.
Q. Revealing the Role of Interfacial Properties on Catalytic
Behaviors by in Situ Surface-Enhanced Raman Spectroscopy.
J. Am. Chem. Soc. 2017, 139, 10339–10346.
Zhang, H.; Wang, C.; Sun, H. L.; Fu, G.; Chen, S.; Zhang, Y. J.;
Chen, B. H.; Anema, J. R.; Yang, Z. L.; Li, J. F.; Tian, Z. Q. In Situ
Dynamic Tracking of Heterogeneous Nanocatalytic Processes
(38)
(39)
(40)
by
Spectroscopy. Nat. Commun. 2017, 8, 1–8.
Hartman, T.; Weckhuysen, B. M. Thermally Stable TiO
SiO -Shell-Isolated Au Nanoparticles for In Situ Plasmon-
Shell-Isolated
Nanoparticle-Enhanced
Raman
(
21)
2
- and
2
(41)
(42)
Enhanced Raman Spectroscopy of Hydrogenation Catalysts.
Chem. - A Eur. J. 2018, 24, 3734–3741.
Hartman, T.; Wondergem, C.; Weckhuysen, B. M. Practical
Guidelines for Shell-Isolated Nanoparticle-Enhanced Raman
Spectroscopy of Heterogeneous Catalysts. ChemPhysChem
(22)
2018, 19, 2461–2467.
(
23)
Carturan, G.; Cocco, G.; Facchin, G.; Navazio, G.
(43)
Sohn, Y.; Wei, W.; White, J. M. Phenylacetylene on Cu(111):
ACS Paragon Plus Environment

ACS Catalysis
Page 10 of 10
Adsorption Geometry, Interfacial Electronic Structures and
Polyphenylacetylene. J. Electron Spectros. Relat. Phenomena
Thermal Chemistry. J. Phys. Chem. C 2007, 111, 5101–5110.
Parker, W. L.; Siedle, A. R.; Hexter, R. M. Raman Spectroscopic
Study of Acetylene on Supported Rhodium Catalysts. J. Am.
Chem. Soc. 1985, 107, 264–266.
Feilchenfeld, H.; Weaver, M. J. Adsorption of Acetylene on
Rhodium- or Platinum-Modified Silver and Gold Electrodes: A
Surface-Enhanced Raman Study. J. Phys. Chem. 1991, 95,
2002, 98–99, 175–187.
Wojdyr, M. Fityk: A General-Purpose Peak Fitting Program. J.
Appl. Crystallogr. 2010, 43, 1126–1128.
Gómez, R.; Solla-Gullón, J.; Pérez, J. M.; Aldaz, A. Surface-
Enhanced Raman Spectroscopy Study of Ethylene Adsorbed
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
(
44)
(47)
(48)
(45)
(46)
on
a Pt Electrode Decorated with Pt Nanoparticles.
ChemPhysChem 2005, 6, 2017–2021.
7
771–7777.
(49)
Heaviside, J.; Hendra, P. J.; Tsai, P.; Cooney, R. P. Adsorption
and Polymerization of Acetylene on Oxide Surfaces. A Raman
Study. J. Chem. Soc. Faraday Trans. 1 1978, 74, 2542–2549.
Polzonetti, G.; Carravetta, V.; Russo, M. V.; Contini, G.; Parent,
P.; Laffon, C. Phenylacetylene Chemisorbed on Pt (111),
Reactivity and Molecular Orientation as Probed by NEXAFS
Comparison
with
Condensed
Multilayer
and
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
ACS Paragon Plus Environment