Highly Networked Platinum–Tin Nanowires as Highly Active and Selective Catalysts towards the Semihydrogenation of Unsaturated Aldehydes

Article abstract of DOI:10.1002/cctc.201800238

The selective hydrogenation of α,β-unsaturated aldehydes to unsaturated alcohols is an important process for many industrial applications, whereas the realization of excellent conversion efficiency and selectivity remains a significant challenge. Herein, we report the preparation of a class of networked Pt–Sn nanowires (Pt–Sn NWs) for the selective hydrogenation of unsaturated aldehydes to the desired unsaturated alcohols. The optimized Pt_1.5Sn NWs delivered a high conversion efficiency (98.1 %) for the hydrogenation of cinnamaldehyde (CAL) and excellent selectivity to cinnamyl alcohol (COL) (90.6 %); thus, they outperformed Pt_1.5Sn nanoparticles (NPs) as well as Pt NPs. The high performance of the Pt_1.5Sn NWs was expanded to the hydrogenation of other α,β-unsaturated aldehydes. X-ray photoelectron spectroscopy revealed that a high ratio of metallic Pt in the Pt_1.5Sn NWs boosted the conversion of CAL and that a high Sn content favored the hydrogenation of the C=O bond, both of which lead to excellent activity and selectivity.

Full text of DOI:10.1002/cctc.201800238

Accepted Article
Title: Networked platinum-tin nanowires as highly active and selective
catalysts towards unsaturated aldehyde semihydrogenations
Authors: Xiaoqing Huang
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DOI: 10.1002/((please add manuscript number))
Article type: Communication
Highly Networked Platinum-Tin Nanowires as Highly Active and Selective
Catalysts towards Unsaturated Aldehyde Semihydrogenations
Meiwu Zhu,1,2,# Bin Huang,1,# Qi Shao,2 Yecan Pi,2 Yong Qian,1,* and Xiaoqing Huang2,*
M. Zhu, B. Huang, Prof. Y. Qian
1Jiangxi Province Key Laboratory of Polymer Micro/Nano Manufacturing and Devices, East
China University of Technology, Nanchang, Jiangxi 330013, China.
E-mail: yqianecit@163.com
M. Zhu, Q. Shao, Y. Pi, Prof. X. Huang
2College of Chemistry, Chemical Engineering and Materials Science, Soochow University,
Jiangsu, 215123, China.
E-mail: hxq006@suda.edu.cn
#M. Zhu and B. Huang contributed equally to this work.
Abstract: The selective hydrogenation of α,β-unsaturated aldehydes to unsaturated alcohols
is an important process for many industrial applications, while the realization of excellent
conversion efficiency and selectivity remains significant challenge. Herein, we reported the
preparation of a class of networked Pt-tin nanowires (Pt-Sn NWs) for selectively
hydrogenating unsaturated aldehydes to the desired unsaturated alcohols. The optimized
Pt1.5Sn NWs deliver high conversion efficiency for cinnamaldehyde (CAL) hydrogenation
(98.1 %) and excellent selectivity to cinnamyl alcohol (COL) (90.6 %), which outperform the
Pt1.5Sn nanoparticles (NPs) as well as the Pt NPs. The high performance of Pt1.5Sn NWs can
also be expanded to other α,β-unsaturated aldehydes hydrogenation. X-ray photoelectron
spectroscopy reveals that the high ratio of metallic Pt in the Pt1.5Sn NWs boosts the CAL
conversion and high content of Sn favors the C=O hydrogenation, respectively, which leads to
the excellent activity and selectivity.
Keyword: Platinum, Tin, Networked Nanowires, Selective Hydrogenation, Unsaturated
Aldehyde
1
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The selective hydrogenation of α,β-unsaturated aldehydes has aroused great attention
because it involves significant steps to yield the widely-used unsaturatured alcohols for the
synthesis of various fine chemicals, particularly in the field of pharmaceuticals, flavourings
and perfumes.[1-4] A typical example is the selective hydrogenation of cinnamaldehyde (CAL)
to cinnamyl alcohol (COL), which is the critical process for desired industrial products.
However, CAL hydrogenation involves in multiple products owing to the competitive
hydrogenation between C=C double bond and C=O double bond, making it difficult to
achieve high selectivity to the targeted products, particularly in the heterogeneous catalysis.[1,
5, 6]
In addition, the hydrogenation of C=O is more unfavorable than that of C=C mainly
because of the thermodynamics favor of C=C hydrogenation over C=O hydrogenation, which
easily lead to the selective formation of hydrocinnamaldehyde (HCAL) rather than the desired
COL.[2, 7, 8] Therefore, improving the efficiency and selectivity of the CAL hydrogenation to
the desirable COL is challenging and significant.
Platinum (Pt)-based nanomaterials were widely studied and demonstrated as the effective
catalysts for hydrogenation.[8-15] However, monometallic Pt is difficult to selectively
hydrogenate C=O when served as the main sites, mainly because the thermodynamic favor of
C=C hydrogenation over C=O hydrogenation.[16-18] To promote the catalytic efficiency and
selectivity as well as minimize the usage of Pt, the classical strategy is to fabricate bimetallic
Pt-based nanostructures for enhancing the selectivity because of the modulated electronic
structure and surface atom arrangement.[19-21] Therefore, the introduction of second non-noble
metals into Pt for the enhanced hydrogenation has attracted tremendous attention.[21-30]
Despite the intense achievements, the development of unique nanostructures with excellent
efficiency and selectivity towards the hydrogenation of α,β-unsaturated aldehydes is still far
from desirable.
2
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Herein, we reported the preparation of a new class of networked bimetallic Pt-tin
nanowires (Pt-Sn NWs) with controlled compositions for the enhanced selective CAL
hydrogenation.[31] The abundant oxidized Sn presented on the surface of Pt-Sn NW promotes
the activation of C=O while decreases the activation of C=C. It turned out that the networked
Pt-Sn NWs showed the excellent activity for the CAL hydrogenation, and exhibited the
increased selectivity to the desired COL and decreased selectivity to hydrocinnamyl alcohol
(HCOL) with the Sn content of Pt-Sn NWs increased. Particularly, the optimized Pt1.5Sn NWs
delivered an outstanding activity of nearly 100% conversion and excellent selectivity to COL
(90.6%), which is superior to those of Pt1.5Sn nanoparticles (NPs) and Pt NPs, showing a new
class of Pt-based catalysts for α,β-unsaturated aldehydes hydrogenation with excellent
efficiency and selectivity.
We prepared the networked Pt-Sn NWs through a simple wet-chemical approach, in
which potassium tetrachloroplatinate (II) (K2PtCl4) and tin (II) chloride (SnCl2) were used as
the metal precursors, benzoin was chosen as shape-controlled agent, polyvinylpyrrolidone
(PVP) was applied as capping agent, and ethylene glycol (EG) was selected as solvent. The
homogeneous mixture was heated at 200 °C for 5 h in a Teflon-lined stainless-steel autoclave
(see the Experimental Section for details). Through the optimization of synthetic conditions,
the benzoin was considered as an essential shape-controlled agent for the preparation of well-
defined PtSn NWs (Figure S1). The product was first characterized by high-angle annular
dark field scanning transmission electron microscopy (HAADF-STEM) (Figure 1a) and
transmission electron microscopy (TEM) (Figure 1b), which clearly revealed that the
ultrathin networked nanostructures consisted of the interlaced NWs with an average diameter
of 2.7 ± 0.8 nm (Figure 1b inset). The atomic ratio of Pt to Sn for the NWs was calculated to
be around 1.5 : 1, by scanning electron microscopy energy-dispersive spectrometer (SEM-
EDS) (Figure 1c), which fit well with their feeding ratio and thus termed as Pt1.5Sn NWs. The
3
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crystalline nature of the networked Pt1.5Sn NWs was characterized by X-ray diffraction
(XRD) (Figure 1d). The representative diffraction peaks at 38.9°, 45.2°, 65.9°, and 79.3° are
close to the (111), (200), (220) and (311) planes of Pt3Sn (JCPDS No. 35-1360), in consistent
with the selected area electron diffraction (SAED) (Figure 1a, inset), confirming the
formation of the alloyed Pt1.5Sn NWs. We further characterized the NWs by high resolution
TEM (HRTEM) and STEM. As shown in Figure 1e, the HRTEM image of the NWs displays
the interplanar spacing of 0.230 nm, correspponding to the (111) plane of Pt3Sn (JCPDS No.
35-1360), in agreement with the XRD result. Moreover, a number of kinks with defects and
atoms steps were observed in the inset of Figure 1e, which can offer vital chances for the
enhanced catalytic system.[32, 33] The alloyed structure of Pt1.5Sn NWs was also confirmed by
the HAADF-STEM elemental mapping (Figure 1f), where the homogeneous distributions of
Pt and Sn in the whole NW were observed.
Interestingly, the presented wet-chemical synthetic method for networked NWs is facile
and robust, which can be extended to the synthesis of other noble metal alloy NWs, including
networked Ru1.5Sn NWs, Rh1.5Sn NWs, and Ir1.5Sn NWs (Figure S2). Although networked
Pt-Sn NWs with different compositions were obtained by varying the content of Sn precursor
supplied (Figure S3), only the pure Pt nanoparticle can be obtained in the absence of Sn
precursor (Figure S4), indicating that the introduction of Sn precursor is critical for the
formation of NWs. To comprehend the composition and structure features of these different
Pt-Sn NWs, we further characterized SEM-EDS and XRD characterizations. The SEM-EDS
spectra show that the atomic ratios of the Pt-Sn NWs were all coherent with the their own
feeding ratios and the composition of spherical Pt1.5Sn NPs was close to that of Pt1.5Sn NWs
(Figure S5, S6). As shown in Figure S7, the XRD patterns of Pt2Sn NWs, Pt3Sn NWs and
Pt4Sn NWs are analogous to that of Pt1.5Sn NWs, all which show obvious peak shift
4
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benchmark with those of the Pt NPs and the standard Pt3Sn XRD card (JCPDS No. 35-1360),
revealing the alloyed properties of the these Pt-Sn NWs.
The as-prepared Pt NPs, Pt1.5Sn NPs and Pt1.5Sn NWs were then evaluated as catalysts
for the selective hydrogenation of CAL. Figure 2a shows the possible reaction pathways of
CAL hydrogenation, where the hydrogenation of C=O double bonds yields the targeted COL,
that of C=C double bonds produces HCAL, and the consecutive hydrogenation of either COL
34]
or HCAL produces HCOL.[15,
Although COL is industrially desired product, the
hydrogenation of C=O double bonds is more unfavorable than that of C=C double bonds
according to the thermodynamics and kinetics.[8, 22, 34] To this end, the kinetic mechanisms of
Pt NPs, Pt1.5Sn NPs and Pt1.5Sn NWs for the hydrogenation of CAL were carefully
investigated by the comparison of the time-tracing reactions. Before the catalytic tests, the
catalysts were dispersed in a mixed solution of CAL and ethanol. The reactions were
performed in the stainless-steel autoclave with fixed stirring speed at near room temperature
and definite hydrogen pressure. The loading amounts of Pt were fixed at 2 mg for all the Pt-
based catalysts, which were determined by the inductively coupled plasma atomic emission
spectroscopy (ICP-AES).
The specific catalytic conversion efficiency and selectivity were presented in Figure 2b-
2d. As shown in Figure 2b, the Pt NPs shows a low selectivity to the desired COL. With the
reaction time changes from 15 min to 60 min, the conversion efficiency of the whole product
increases gradually with no obvious selectivity to COL, HCAL or HCOL. With the similar
spherical shape as Pt NPs, the Pt1.5Sn NPs exhibited a stable selectivity of roughly 83 % to
COL and the conversion efficiency strengthened from 27.2 % to 87.3 % for the duration of 60
min reaction (Figure 2c), revealing the enhanced conversion efficiency and selectivity
achieved by the introduction of Sn. The networked Pt1.5Sn NWs with similar composition but
different shape compared with Pt1.5Sn NPs were further explored for the hydrogenation of
5
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CAL in details. As shown in Figure 2d, the product after 15 min reaction shows 55.3 %
conversion efficiency and high selectivity of 87.2 % to the targeted COL, and negligible
selectivity to HCAL and HCOL. As reaction time is extended to 30 min, the conversion
efficiency of product increases to 94.3 % and the selectivity to COL is up to 88.9 %, whereas
the selectivity to HCAL or HCOL is still extremely low. With the reaction going to 45 min,
the content of COL product slowly increases to 89.6 % while the conversion efficiency
maintains above 90 %, indicating the excellent catalytic efficiency and the COL selectivity.
When reaction time is 60 min, the selectivity to COL and the conversion of product have
slight improvements with limited selectivity to HCOL. These time-tracing conversion
efficiency and intermediates changes for the hydrogenation of CAL revealed several attractive
features as follows: (1) Pure Pt NPs is unfavorable for selectively hydrogenating CAL to COL
but can promote the conversion efficiency due to the high active sites from ultrasmall
nanostructure,[16] (2) Pt-Sn alloy can favor the adsorption of C=O double bonds to the
desirable COL, and (3) the networked NWs structure is of more active sites and higher
utilization efficiency to hydrogenate CAL than spherical NPs likely due to the unique
nanostructure and alloy effect.[35, 36] Furthermore, we also studied the stability of Pt1.5Sn NWs
for CAL hydrogenation by five recycle tests, where the selectivity to COL keeps high, while
the conversion efficiency drops from 99.4% to 34.0%, which may be attributed to the heavy
aggregation of the catalysts (Figure S8).
To deeply understand the role of Pt-Sn NWs in the selective CAL hydrogenation, a series
of composition-controlled networked Pt-Sn NWs and spherical Pt-based NPs were further
investigated. For a comprehensive evaluation of the catalytic properties of CAL
hydrogenation, these Pt-based catalysts with the same Pt loadings were carried out under the
same experimental conditions. As shown in Table 1 and Figure S9a, the Pt1.5Sn NWs exhibit
the best selectivity (90.6 %) to COL and excellent conversion (98.1 %) among all the Pt-Sn
6
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NWs within 1 h. Particularly, the hydrogenation products of C=C are negligible (the
selectivities of both HCAL and HCOL are less than 10 %), which displays the optimal
composition of Pt-Sn NWs for the adsorption of C=O double bonds to the desirable COL. In
the case of the networked Pt2Sn NWs, almost 100 % conversion of the product and 87.6 %
selectivity to COL and 12.2 % selectivity to HCOL are observed, indicating that distinct
selective hydrogenation of C=O. With decreasing the Sn content, the networked Pt3Sn NWs is
of same high CAL conversion (99.7 %), in which negligible catalytic performance for
selective activation of C=C (3.3 %) while the selectivity toward COL decreases to 69.1 %
with that of HCOL increases to 27.6 %, suggesting the interaction with the C=O and further
hydrogenation of COL to HCOL. Remarkably, the lowest Sn content of networked Pt4Sn
NWs shows roughly 100 % CAL conversion within 1 h, with a relatively high selectivity of
84.7 % to HCOL and limited selectivity to COL or HCAL. The preferential absorption of
C=O diminishes distinctly, attributing to the consecutive hydrogenation of COL. Moreover,
the spherical Pt1.5Sn NPs with the same composition as the optimal Pt1.5Sn NWs was also
compared (Table 1 and Figure S9b), which exhibited relatively high conversion (87.3 %) and
high selectivity toward COL (86.3 %) despite inferior to that of Pt1.5Sn NWs, indicating the
favorable hydrogenation of the C=O rather than that of the C=C for the composition-
controlled Pt1.5Sn nanomaterials. On the other hand, to gain better understanding of the role of
Sn on the reaction, the activity of pure Pt NPs was further explored for comparison. Although
no noticeable selectivity to the desired COL, HCAL or HCOL was found, Pt NPs benefitted
the hydrogenation of CAL due to the appearance of good conversion efficiency (76.3 %).[10]
This result confirms that pure Pt NPs interact with both C=O and C=C without performing the
specific selective CAL hydrogenation to the definite products.[5] With the introduction of Sn
in Pt NPs, the Pt1.5Sn NPs exhibited superior performance to activate C=O to the desired COL.
Furthermore, the increased selectivity to the targeted COL (from 14.5 % to 90.6 %) and
decreased selectivity to HCOL (from 84.7 % to 8.2 %) with the Sn content increased in
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various Pt-Sn NWs, in which Pt1.5Sn NWs presented the excellent conversion and enhanced
selectivity to the targeted COL, indicating the well-tunable adsorption of C=O bonds to the
desired COL in the Pt1.5Sn NWs.
Significantly, the high activity and selectivity of Pt1.5Sn NWs can be expanded to other
α,β-unsaturated aldehydes hydrogenation, where the desirable other industrially unsaturated
alcohol can be readily realized by hydrogenating corresponding α,β-unsaturated aldehydes
(Table 2 and Figure S10). For example, as a typical unsaturated aldehyde, furfural (FAL)
hydrogenation can be happened under mild reaction by adding the Pt1.5Sn NWs, in which the
FAL hydrogenation was of 100 % conversion efficiency and the C=O was readily
hydrogenated to furfuryl alcohol with especial high selectivity (99.2 %). Similar phenomenon
also appeared in the 3-methyl-2-butenal (MBL) hydrogenation, which exhibited 100 %
conversion with pretty high selectivity to 3-methyl-2-butenol (91.0 %) and low selectivities to
3-methyl butyraldehyde as well as the over-hydrogenation product. For the hydrogenation of
crotonaldehyde (CTL), high conversion efficiency (88.8 %) and selectivity of C=O to crotyl
alcohol (71.3 %) were also achieved under mild condition by using Pt1.5Sn NWs as the
catalysts.
The enhanced activity and selectivity for the CAL hydrogenation on the composition-
controlled Pt-Sn NWs can be related to the chemical states of Pt and Sn. We thus investigated
the surface states of these Pt-based nanomaterials by X-ray photoelectron spectroscopy (XPS).
As shown in Figure 3a, the Pt in these Pt-based nanomaterials are all composed of the
metallic state Pt (Pt0) and oxidized state Pt (Pt2+). The binding energy of Pt0 shifts slightly to
higher position with the content of Sn increased in the Pt-Sn NWs, which is higher than that
of Pt NPs, revealing the electron-transferred effect from electropositive Sn to electronegative
Pt. The Sn 3d XPS spectra of these Pt-Sn nanomaterials are also analyzed in Figure 3b,
which can be split into two doublets peaks of Sn2+ and Sn4+ with no distinct metallic Sn is
8
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observed, revealing the presence of abundant oxidized Sn on the surface of these Pt-Sn NWs
and the Pt1.5Sn NPs. Furthermore, the atomic ratios of Pt0/Pt2+ and the corresponding
conversion efficiency are plotted in Figure 3c, in which the composition-controlled Pt-Sn
NWs shows higher Pt0/Pt2+ ratio than the Pt NPs while the Pt0/Pt2+ ratio of the Pt-Sn NWs is
higher than that of Pt1.5Sn NPs, indicating the addition of Sn leads to the improved atomic
ratio of Pt0/Pt2+. In addition, all these Pt-Sn NWs showed almost 100 % conversion for the
CAL hydrogenation, where the conversion efficiency is higher than that of the Pt1.5Sn NPs
and Pt NPs with the Pt1.5Sn NPs excelled the Pt NPs. The change in the Pt0/Pt2+ atomic ratio is
in consistent with the activity trends of CAL hydrogenation, where the increased the Pt0/Pt2+
atomic ratio results in the improved hydrogenation activity, indicating that the metallic Pt is
the main active sites for the hydrogenation.[37] Moreover, the atomic ratios of Sn/Pt were
further calculated and the selectivity for hydrogenating CAL to COL of various catalysts are
shown in Figure 3d. The Sn/Pt ratio of the various Pt-Sn NWs increased with Sn content
increased, indicating the successful introduction of Sn into Pt-Sn NWs. The high Sn/Pt ratio
in Pt1.5Sn NPs further demonstrated the existence of high content Sn. Especially, the volcano-
type plot of Sn/Pt ratios matched well with the corresponding selectivity plot for the CAL
hydrogenation to COL. Lowering the Sn/Pt ratio in the various Pt-Sn NWs associated with the
decrease of the COL selectivity, indicating that abundant oxidized Sn boosts the COL
selectivity and can turn the selectivity to desired COL. The addition of oxidized Sn in Pt
favored the hydrogenation of C=O double bonds to COL, which was also confirmed by
comparing the Sn/Pt ratio plot and selectivity plot of the Pt1.5Sn NPs and pure Pt NPs (Figure
3d).
In summary, we have demonstrated a facile method for the preparation of a class of Pt-
Sn NWs with networked structure and controlled composition. Benefitting from the unique
structure and alloy effect, the networked Pt1.5Sn NWs exhibit promising performance for
9
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selective hydrogenation of CAL to the industrially required COL, outperforming both the
spherical Pt1.5Sn NPs and the spherical Pt NPs. The Pt-Sn NWs show the increased selectivity
(from 14.5 % to 90.6 %) to the targeted COL and decreased selectivity (from 84.7 % to 8.2 %)
to over-hydrogenation HCOL with the content of Sn increased. XPS studies demonstrated that
the enhanced activity arises from the high ratio of metallic Pt and the high COL selectivity
attributes to high content of Sn. The present work provides a promising strategy to enhance
the hydrogenation reaction through precise structure and composition tuning of the alloyed
catalysts.
Supporting Information
Supporting Information is available from the Wiley Online Library or from the author.
Acknowledgements
This work was financially supported by the Ministry of Science and Technology
(2016YFA0204100, 2017YFA0208200), the National Natural Science Foundation of China
(21571135), Young Thousand Talented Program, the start-up fundings from Soochow
University, the Priority Academic Program Development of Jiangsu Higher Education
Institutions (PAPD).
Received: ((will be filled in by the editorial staff))
Revised: ((will be filled in by the editorial staff))
Published online: ((will be filled in by the editorial staff))
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ChemCatChem
Figures
Figure 1. (a) HAADF-STEM image and SAED pattern in the inset, (b) TEM image and size distribution
pattern of the product in the inset, (c) SEM-EDS, (d) XRD pattern, (e) HRTEM image, and (f) HAADF-
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10.1002/cctc.201800238
ChemCatChem
STEM image and elemental mappings of the networked Pt1.5Sn NWs. Dashed lines and red dots in (e)
indicate the defects and atom steps, respectively.
Figure 2. (a) Scheme of hydrogenation pathway of CAL. Time-tracing reactions of (b) Pt NPs, (c) Pt1.5Sn
NPs and (d) Pt1.5Sn NWs for selective hydrogenation of CAL to COL, HCAL and HCOL. Reaction
conditions: catalyst (contains 2 mg Pt), CAL (0.8 mmol), ethanol (5 mL), stirred speed (500 rpm), 30 °C,
and H2 (3 MPa).
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10.1002/cctc.201800238
ChemCatChem
Table 1. Selective hydrogenation of CAL by different catalysts.
Catalysts
T
(°C)
Time
(h)
Conv.
(%)
Select. (%)
HACL
1.2
COL
90.6
87.6
69.1
14.5
86.3
39.4
HCOL
8.2
Pt1.5Sn NWs
Pt2Sn NWs
Pt3Sn NWs
Pt4Sn NWs
Pt1.5Sn NPs
Pt NPs
30
30
30
30
30
30
1
1
1
1
1
1
98.1
99.3
99.7
99.9
87.3
76.3
0.2
12.2
27.6
84.7
7.0
3.3
0.8
6.7
33.2
27.4
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Table 2. Selective hydrogenation of different α,β-unsaturated aldehydes with
Pt1.5Sn NWs.
FAL
MBL
CTL
Substrat
es
T
Time
(h)
Conv.
(%)
Select. (%)
C=C
(°C)
C=O
C=C
C=O
0
FAL
MBL
CTL
40
40
40
2
2
1
100
100
88.8
99.2
91.0
71.3
0.8
9.0
4.0
0
24.7
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Figure 3. (a) Pt 4f XPS spectra. (b) Sn 3d XPS spectra of various catalysts. (c) Plots of atomic ratios of
Pt0/Pt2+ and conversion of CAL toward different Pt-based catalysts and the corresponding conversion
efficiencies for CAL hydrogenation. (d) Plots of atomic ratios of Sn/Pt and selectivity to COL toward
different Pt-based catalysts.
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The table of contents entry
Composition-controlled networked Pt-Sn nanowires (NWs) were successfully prepared
through a facile wet-chemical approach. The Pt-Sn NWs show a volcano-type activity and
selectivity of cinnamaldehyde hydrogenation to cinnamyl alcohol (COL) as a function of Sn
content. The optimized Pt1.5Sn NWs is highly active and selective towards cinnamaldehyde
hydrogenation with the conversion of 98.13 % and the COL selectivity of 90.62 %, as well as
towards the other α,β-unsaturated aldehydes hydrogenation.
Keyword: Platinum, Tin, Networked Nanowires, Selective Hydrogenation, Unsaturated
Aldehyde
Meiwu Zhu,1,2,# Bin Huang,1,# Qi Shao,2 Yecan Pi,2 Yong Qian,1,* and Xiaoqing Huang2,*
Highly Networked Platinum-Tin Nanowires as Highly Active and Selective Catalysts towards
Unsaturated Aldehyde Semihydrogenations
TOC figure
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