CoOx@Co Nanoparticle-based Catalyst for Efficient Selective Transfer Hydrogenation of α,β-Unsaturated Aldehydes

Article abstract of DOI:10.1002/cctc.201901996

Currently, developing simple and effective catalysts for selective hydrogenation of α,β-unsaturated aldehydes to unsaturated alcohols is challenging. Herein, an efficient CoO_x-shell/Co-core structured nanoparticle catalyst is synthesized by a facile ultrasonic-assisted carbothermal reduction method. The resultant catalyst exhibits outstanding catalytic performance toward the selective transfer hydrogenation of a wide spectrum of α,β-unsaturated aldehydes into corresponding unsaturated alcohols with over 90 % selectivity. This is the simplest nonprecious metal catalyst to be reported for the selective hydrogenation of unsaturated aldehydes.

Full text of DOI:10.1002/cctc.201901996

Accepted Article
Title: CoOx@Co Nanoparticle-based Catalyst for Efficient Selective
Transfer Hydrogenation of α,β-Unsaturated Aldehydes
Authors: Wanbing Gong, Miaomiao Han, Chun Chen, Yue Lin,
Guozhong Wang, Haimin Zhang, and Huijun Zhao
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To be cited as: ChemCatChem 10.1002/cctc.201901996
Link to VoR: http://dx.doi.org/10.1002/cctc.201901996
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ChemCatChem
10.1002/cctc.201901996
CoO @Co Nanoparticle-based Catalyst for Efficient Selective Transfer Hydrogenation
x
of α,β-Unsaturated Aldehydes
+
+
*
*
Wanbing Gong, Miaomiao Han, Chun Chen, Yue Lin, Guozhong Wang, Haimin Zhang
*
and Huijun Zhao
Dr. W. Gong, Dr. M. Han, Dr. C. Chen, Prof. G. Wang, Prof. H. Zhang, Prof. H. Zhao
Key Laboratory of Materials Physics, Centre for Environmental and Energy Nanomaterials,
Anhui Key Laboratory of Nanomaterials and Nanotechnology, CAS Center for Excellence in
Nanoscience, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, P.
R. China
E-mail: zhanghm@issp.ac.cn, h.zhao@griffith.edu.au
Dr. Y. Lin
Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and
Technology of China, Hefei 230026, P. R. China
E-mail: linyue@ustc.edu.cn
Prof. H. Zhao
Centre for Clean Environment and Energy, Griffith University, Gold Coast Campus,
Queensland 4222, Australia
+
These authors contributed equally to this work.
Keywords: unsaturated aldehydes, transfer hydrogenation, carbothermal, CoO , core-shell
x
1
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ChemCatChem
10.1002/cctc.201901996
Abstract
Currently, developing simple and effective catalysts for selective hydrogenation of α,β-
unsaturated aldehydes to unsaturated alcohols is challenging. Herein, an efficient CoOx-
shell/Co-core structured nanoparticle catalyst is synthesized by a facile ultrasonic-assisted
carbothermal reduction method. The resultant catalyst exhibits outstanding catalytic
performance toward the selective transfer hydrogenation of a wide spectrum of α,β-
unsaturated aldehydes into corresponding unsaturated alcohols with over 90% selectivity.
This is the simplest nonprecious metal catalyst to be reported for the selective hydrogenation
of unsaturated aldehydes.
2
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ChemCatChem
10.1002/cctc.201901996
Selective hydrogenation of the C=O group against the conjugated C=C group in α,β-
unsaturated aldehydes to produce the unsaturated alcohols is crucially important to meet the
[
1]
increasing demands of flavouring, perfume and pharmaceutical industries. However,
selective hydrogenation of α,β-unsaturated aldehydes is highly challenging because
[
2]
comparing to C=C, the hydrogenation of C=O is thermodynamically unfavoured. Although
the platinum group metals-based catalysts can achieve high conversion, they suffered from
[
3]
low selectivity to produce the desired unsaturated alcohols. Huge efforts have therefore
been devoted to develop new catalyst structures capable of overcoming the thermodynamic
limitation for selective production of unsaturated alcohols. A main strategy has been focused
[
4]
on enhancing the selectivity of Pt-based catalysts. For instance, Pan et al. synthesized a Fe-
doped PtFe /15AS catalyst and utilized the synergetic effects of Pt and FeO to achieve
x
x
[
4b]
selective hydrogenation of cinnamaldehyde (CAL) to cinnamyl alcohol (COL).
Huang’s
group constructed a Pt Co@Co(OH) catalyst for selective hydrogenation of CAL with a high
3
2
[
4c]
COL selectivity of 91.3%.
Significantly, they confirmed that the high electron-cloud
density of Pt sites resulting from the transferring electrons from Co(OH) can effectively
2
suppress the hydrogenation of C=C to enable selective hydrogenation of C=O. High COL
selectivities (> 90%) also achieved by creating electron-rich metallic Pt species using Pt-Co
[4d]
[5]
bimetallic in Pt-Co/MWCNTs
and interactions with CeO -ZrO substrate. We recently
2 2
reported that the interactions of MOF node-ions with α,β-unsaturated aldehydes make the Pt
[1a]
catalysed hydrogenation on C=O thermodynamically more favourable than that of C=C.
Despite the progress, the use of precious metal-based catalysts will never be a desire choice
due to their high costs, scarcity and difficulty for scalable synthesis. It is therefore necessary
to develop cheap and plentiful high performance nonprecious metal catalysts that can be
synthesized via a simple procedure and in large quantity. In this regard, Miura’s group
[
6]
reported the use of Co/Al O for selective hydrogenation of various unsaturated aldehydes.
2
3
Li’s group demonstrated the use of surface Lewis acid-promoted copper-based nanocatalysts
3
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ChemCatChem
10.1002/cctc.201901996
to achieve selective hydrogenation of citral (CTL) with over 75% selectivity toward allylic
[
7]
alcohol. Recently, Wei’s group used a CoGa catalyst to achieve selective hydrogenation of
3
[
2a]
CAL to COL with a high selectivity of 96%.
However, the reported selective
hydrogenation of α,β-unsaturated aldehydes to date was almost exclusively carried out via
direct hydrogenation. Compared to the direct hydrogenation, the transfer hydrogenation (TH)
can alleviate safety concerns of high-pressure and flammable hydrogen gas, and reduce the
[
8]
complexity and capital costs of the reactors. In this respect, Schüth’s group recently
demonstrated for the first time of using a nonprecious catalyst to achieve selective transfer
[
9]
hydrogenation (STH) of α,β-unsaturated aldehydes with 2-propanol as hydrogen donor.
o
With a 120 C reaction temperature, the reported mesoporous carbon supported Co O
3
4
nanoparticles (NPs) catalyst (Co O /MC) can completely convert furfural (FAL), CAL and
3
4
CTL to their corresponding unsaturated alcohols with 97%, 95% and 95% selectivity within 8,
2
4 and 48 h, respectively.
Herein, we report a facile and scalable method to synthesize an activated carbon (AC)
supported CoO @Co NPs as a highly efficient STH catalyst to convert a wide range of α,β-
x
unsaturated aldehydes into corresponding unsaturated alcohols with over 90% selectivities.
The synthetic method involves two steps (Figure S1). An ultrasonic-assisted impregnation
step was employed to achieve high Co precursor loading on AC in a highly dispersed forms.
The carbothermal reduction properties of AC was then applied to convert the loaded Co
precursors to CoO modified Co NPs (CoO @Co) via Co(NO ) + C  CoO @Co + CO/CO
x
x
3 2
x
2
[
10]
+
NO in a controllable manner.
The highly dispersed Co precursors resulting from the
x
ultrasonic-assisted impregnation adding to the limited mobility of the loaded Co under the
solid-state carbothermal reduction conditions enables us to control the resultant CoO @Co in
x
a form of uniformly dispersed small-sized NPs.
The effect of calcination treatment temperature was firstly investigated. The samples
o
subjected to 400, 500 and 600 C treatments are denoted as CoO -400, CoO @Co-500 and
x
x
4
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ChemCatChem
10.1002/cctc.201901996
CoO @Co-600, respectively. The obtained TEM images (Figures S2a-c) reveal that Co NPs
x
are uniformly distributed within the carbon matrix and an increase in the calcination
temperature leads to an increase in NPs’ size. The mean NPs sizes for CoO -400, CoO @Co-
x
x
5
00 and CoO @Co-600 are 5.6, 6.2 and 6.4 nm, respectively (Table S1). CoO @Co-500 was
x x
o
further treated at 450 C for 4 h under a constant flow of 10 vol % H /N (denoted as Co-500-
2
2
4
50). The TEM image of Co-500-450 (Figure S2d) reveals slightly aggregated Co NPs with
an increased mean NPs size from 6.2 nm to 10.2 nm (Table S1). Despite this, the Co NPs in
all ultrasonically treated samples are uniformly distributed in the carbon matrix with relatively
small particle sizes. For comparative purpose, a sample (denoted as CoO @Co-500-c) was
x
synthesised using the same synthetic procedure as that of CoO @Co-500, except ultrasonic
x
treatment. In strong contrast to the ultrasonically treated samples, the Co NPs in CoO @Co-
x
5
00-c are severely aggregated (Figure S3). This confirms the important role of the ultrasonic-
assisted impregnation in preventing Co NPs from aggregation. Figure S4 shows the X-ray
diffraction (XRD) patterns of the ultrasonically treated samples. The CoO -400 is dominated
x
by CoO phase due to the weak carbothermal reduction capability under such a low
x
temperature. The CoO and metallic Co phases are co-existed in CoO @Co-500 and
x
x
CoO @Co-600. Nevertheless, the intensities of metallic Co peaks are increased with the
x
increased calcination temperature due to the increased strength of carbothermal reduction
under higher temperatures. The Co-500-450 is dominated by the metallic Co phase, resulting
from the strong reduction ability of H . The X-ray photoelectron spectroscopy (XPS) spectra
2
(
Figure S5) further confirm the dominant CoO phase in CoO -400, co-existence of CoO and
x x x
metallic Co phases in CoO @Co-500 and CoO @Co-600, and the dominant metallic Co
x
x
phase in Co-500-450. The O 1s XPS spectra indicate the presence of lattice oxygen species
(O1, ~530.2 eV), surface oxygen species (O2, ~531.8 eV) and adsorbed oxygen species (O3,
[
11]
~
533.2 eV). The Raman spectra also confirm the increased contents of metallic Co when
o
o
the calcination temperature increased from 400 C to 600 C (Figure S6), consistent with the
5
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ChemCatChem
10.1002/cctc.201901996
[12]
obtained XPS results. The specific surface area and porous structure of the ultrasonically
treated samples were investigated (Figure S7 and Table S1). The dominant pore sizes of < 2
nm are observed from all samples investigated, indicating a microporous dominated porous
structure. The specific surface areas and the pore volumes follow an order of CoO -400
x
(
727/0.283) < CoO @Co-500 (774/0.311) < CoO @Co-600 (874/0.337) < Co-500-450 (875
x
x
2
-1
3
-1
m g /0.369 cm g ). Interestingly, the inductively coupled plasma spectroscopy (ICP)
analysis data reveal that the Co contents in all samples are essentially the same (15.5% -
1
5.9%, Table S1), suggesting that the calcination temperature has insignificant effect on the
Co content. However, when CoO and metallic Co are co-exist, to depict the catalytic activity
x
origin, the compositional structures of Co NPs need to be confirmed.
6
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ChemCatChem
10.1002/cctc.201901996
Figure 1. (a) Typical TEM images (Inset: high magnification image); (b) HAADF-STEM
image and EDX mapping; (c) HRTEM image; (d) FFT images; (e) EELS elemental maps of
one particle of CoO @Co-500 catalyst.
x
The structural characteristics of CoO @Co-500 was therefore investigated in details. The
x
transmission electron microscopy (TEM) images (Figure 1a) reveal a uniformly dispersed Co
NPs on the AC carbon matrix. The corresponding elemental mapping images from high-angle
annular dark-field scanning transmission electron microscopy (HAADF-STEM) indicate the
homogeneously distributed Co, O and C throughout the entire architecture (Figure 1b). The
aberration-corrected high resolution TEM (HRTEM) image (Figure 1c) shows the lattice
spacing of 0.204/0.177 nm, and 0.245/0.212 nm from the core and outer regions of a NP,
which can be respectively indexed to the (111) and (002) planes of metallic Co, and the (111)
and (200) planes of CoO, confirming a Co-core/CoO-shell NP structure. The average CoO-
shell thickness is found to be ~1 nm. It should be noted that the presence of metallic Co in the
CoO-shell is clearly visible, indicating the shell is a CoO/metallic Co composite. The fast
Fourier transform (FFT) patterns (Figure 1d) further confirm the co-existence of the metallic
Co and CoO. The Co-core and CoO-shell NP structure can also be directly visualized from
the spatial elemental distribution within a single NP (Figure 1e) mapped by the electron
energy loss spectroscopy (EELS).
7
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ChemCatChem
10.1002/cctc.201901996
Figure 2. (a) Effect of reaction temperature (Solvent: 2-propanol, Reaction time: 5 h), (b)
o
Reaction time (Solvent: 2-propanol, Reaction temperature: 120 C) and (c) Solvent (Reaction
o
temperature: 120 C, Reaction time: 5 h) on conversion and selectivity; (d) Reusability
o
(
Solvent: 2-propanol, Reaction temperature: 120 C, Reaction time: 3 h). All reactions were
carried out using 30 mg CoO @Co-500 with 0.3 mmol CAL in 5 mL solvent at atmospheric
x
N .
2
The STH performance of CoO @Co-500 to convert CAL to COL was investigated. As can
x
be seen from Figure 2a, when the reaction time is fixed at 5 h, the conversion of CAL
increases evidently from 13.1% to 89.7% as the reaction temperature increased from 80 °C to
1
20 °C and further increases to 100% at 140 °C due to the high temperature accelerated
[
13]
dehydrogenation of 2-propanol. In contrast, an increased reaction temperature from 80 °C
to 120 °C leads to a decreased COL selectivity from 100% to 90.9%. A further temperature
increase to 140 °C results in a sharply decreased COL selectivity to 20.9% because the C-C or
o
C-O bonds are activated at high temperatures. Under a fixed temperature of 120 C, when the
reaction time is from 3 h to 8 h, the conversion of CAL is increased from 56.8% to 97.5%,
while the COL selectivity is decreased from 93.5% to 90.1% (Figure 2b). Although 100%
conversion of CAL is achievable when the reaction time is further increased to 14 h, the COL
selectivity is rapidly deceased to 80.1%. The effect of solvent was also investigated (Figure
8
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ChemCatChem
10.1002/cctc.201901996
2
c). High COL selectivities (> 85%) can be obtained from all solvents investigated. However,
the conversion of CAL varies significantly between 10.6% and 89.7%, following a decreased
order of: 2-propanol > ethanol > 2-butanol > 2-pentanol > methanol. The reusability was also
examined (Figure 2d). The experiments were carried out using a short reaction time of 3 h.
Although the selectivity remains essentially unchanged, a noticeable decrease in CAL
conversion during the fourth reuse cycle is observed. Compared to the fresh CoO @Co-500
x
(
Figure 1a), an increased CoO content (Figure S8a) and slightly aggregated Co NPs (Figure
x
S8b) are observable from the reused catalyst (CoO @Co-500-reused), which could be
x
responsible for the observed performance decay. An attempt was then made to regenerate the
catalyst. The result indicates that after the fourth reuse experiment, a simple thermal treatment
o
of CoO @Co-500-reused at 500 C for 2 h in N atmosphere can recover 100% of the lost
x
2
conversion activity (Figure 2d). XRD pattern (Figure S8a) and TEM image (Figure S8c)
reveal that both CoO content and Co NP size in CoO @Co-500-regenerated are reduced. In
x
x
order to evaluate the practicality, a gram-scale experiment was carried out using 0.5 g of CAL
o
as substrate under atmospheric N and 130 C for 12 h. An impressive CAL conversion of
2
8
0.1% and a COL selectivity of 90.3% can be achieved.
a)
Table 1. STH of α,β-unsaturated aldehydes
o
En Substrate Product Temp ( C) Time (h) Conv (%) Sel (%)
1
2
120
120
8
12
97.5
91.7
90.1
92.3
3
120
13
98.9
94.8
4
5
6
7
120
100
120
140
8
12
10
8
98.9
91.6
92.6
90.9
96.9
90.9
90.3
91.1
a)
All reactions were carried out using 30 mg CoO @Co-500 and 0.3 mmol substrate in 5 mL
x
2
-propanol at atmospheric N2.
The investigation was also carried out to evaluate the STH performance of CoO @Co-500
x
for other important α,β-unsaturated aldehydes including α-methylcinnamylaldhyde (MCAL),
9
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ChemCatChem
10.1002/cctc.201901996
CTL, FAL, 3-(2-Furyl)acrolein (FAC), 2-methyl-2-pentenal (MPL) and crotonaldehyde
CTA) (Table 1). Impressively, over 90% conversion and selectivity can be achieved for all
(
cases investigated, confirming a generic applicability of CoO @Co-500 for STH of α,β-
x
unsaturated aldehydes. For methyl-containing MCAL, a 91.7% conversion to α-methyl
cinnamyl alcohol (key intermediate for production of medicine, perfume and additives) with
o
9
2.3% selectivity can be achieved within 12 h at 120 C (entry 2, Table 1). CTL contains two
o
C=C bonds and one C=O bond. Under 120 C, 98.9% of CTL can be converted to nerol and
geraniol (highly demanded precursors for production of flavours, cosmetics, pharmaceuticals
[
7, 14]
and insect repellants)
with 94.8% selectivity in 13 h (entry 3, Table 1). Comparatively,
under the same reaction temperature, the STH of CTL by the reported Co O /MC catalyst
3
4
[
9]
requires 48 h to achieve a 99% conversion with 95% selectivity. Selective hydrogenation of
biomass-derived FAL to furfuryl alcohol (FOL) is another class of important hydrogenation
[
15]
reactions to produce fine and bulk chemicals. A FAL conversion efficiency of 98.9% with
o
a FOL selectivity of 96.9% can be achieved in 8 h at 120 C (entry 4, Table 1). FAC can be
considered as a heterocyclic analogue of CAL and used to produce 3-(2-Furyl)allyl alcohol,
which is a key chemical intermediate for synthesising fine chemicals, polymers and
[
16]
biofuels. A 91.6% conversion with 90.9% selectivity can be achieved within 12 h at a low
o
reaction temperature of 100 C (entry 5, Table 1). MPL contains no ring structure and its
selective hydrogenation product, 2-methyl-2-pentenol, is demanded for production of fine
[
17]
o
chemicals. A 92.6% conversion with 90.3% selectivity can be obtained at 120 C within 10
h (entry 6, Table 1). CTA also contains no ring structure and has been used to produce crotyl
[
3b]
alcohol, a key intermediate in the chemical industry. Over 90% CTA conversion and crotyl
o
alcohol selectivity are achievable within 8h, however, a higher reaction temperature of 140 C
is required (entry 7, Table 1). These results show that such an oxide-modified Co catalyst is
highly efficient for STH of a wide spectrum of α,β-unsaturated aldehydes with high
conversion and selectivity. In contrast, extremely poor selectivities (6.5% - 20.2%) toward the
1
0
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ChemCatChem
10.1002/cctc.201901996
unsaturated alcohols are obtained when such a catalyst is used for direct hydrogenation with
H as the hydrogen source (Table S2), suggesting that different catalytically active site
2
structures are required to achieve efficient selective hydrogenation of unsaturated aldehydes via
direct and transfer hydrogenation routes.
a)
Table 2. STH of CAL to COL over the different Co catalysts
b)
-1
En
1
Catalyst
AC
Conv (%)
--
Sel (%)
--
TOF (h )
--
2
3
4
5
CoO -400
36.8
89.7
25.8
24.5
76.5
90.9
98.5
99.7o
1.6
4.2
1.2
1.9
x
CoO @Co-500
x
CoO @Co-600
x
Co-500-450
a)
Reaction conditions: 30 mg catalyst, 0.3 mmol CAL, 120 C ,atmospheric N , 5 h, 5 mL 2-
2
propanol as solvent.
b)
TOF = molconverted CAL/(molexposed surface Co·h).
The STH performances of cobalt-containg catalysts for converting CAL to COL were
examined to depict catalytic activity of CoO modified Co catalysts (Table 2). First, the AC is
x
inactive in this STH process, suggesting that Co sites account for the hydrogenation
performance. Although ICP analysis indicates essentially same total cobalt contents (15.5% -
1
5.9%) in these catalysts, the XRD and XPS results confirm that the metallic Co contents of
these catalysts follow an increasing trend of CoO -400 < CoO @Co-500 < CoO @Co-600 <
x
x
x
Co-500-450. Interestingly, the COL selectivity increase follows the same order: 76.5% for
CoO -400 < 90.9% for CoO @Co-500 < 98.5% for CoO @Co-600 < 99.7% for Co-500-450,
x
x
x
indicating higher metallic Co contents are favourable for STH of CAL. However, the effect of
cobalt composition on CAL conversion is more complex. Very poor CAL conversions of
3
6.8% and 24.5% are obtained from the CoO dominated CoO -400 and the metallic Co
x x
dominated Co-500-450. Although CoO and metallic Co co-exist in both catalysts, the CAL
x
conversion achieved by CoO @Co-500 (89.7%) is more than three-fold of that achieved by
x
CoO @Co-600 (25.8%). Meanwhile, the CoO @Co-500 catalyst possesses highest TOF
x
x
-1
value (4.2 h ). In addition, it can be found that the catalysts with different Co loadings show
Co-core and CoO-shell NP structure, and the particle sizes increase gradually with the
1
1
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10.1002/cctc.201901996
increase of Co loading (Figure S9). As can be seen from Figure S10, we could find that Co
loading has a great influence on CAL conversion. The CAL conversion increases first and
then remains unchanged with the increase of Co loading, and a 89.7% conversion is obtained
over the optimum 15.6 wt% CoOx@Co-500 catalyst. These evidences indicate that a balanced
CoO and metallic Co contents in this type of catalyst is critically important for achieving
x
high CAL conversion.
Figure 3. Optimized geometry for the most stable configuration of CAL on the catalyst
surfaces: (a) Co (111), (b) 9O/Co (111) and (c) CoO (111). Blue, red, brown, and white
spheres represent cobalt, oxygen, carbon and hydrogen atoms, respectively.
Considering these cobalt-containg catalysts are a Co-core and CoO -shell structured NPs,
x
an increased metallic Co contents means a decreased CoO shell thickness. The catalyst
x
performance should therefore be dependent on the composition and thickness of the CoOx-
shell. DFT calculations were subsequently employed to illustrate the effect of surface
composition on possible reaction pathways. Based on HRTEM results (Figure 1c), the (111)
plane is chosen for DFT calculations. Figure 3 shows the most stable CAL adsorption
configurations via C=O on the surface of (111) plane with different contents of CoO. For
metallic Co (111), the calculated adsorption energy is -45 kJ/mol (Figure 3a), indicating a
relatively weak CAL adsorption, unfavourable for efficient conversion. When the oxides is
presence (e.g., 9O/Co (111)), the calculated adsorption energy is decreased to -50 kJ/mol
(Figure 3b), indicating an increased adsorption ability toward CAL that is favourable for CAL
conversion. With the pure CoO (111) surface, surprisingly, the adsorption energy is found to
be dramatically reduced to -1912 kJ/mol (Figure 3c), indicating an extremely strong CAL
1
2
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10.1002/cctc.201901996
adsorption, which infers a decreased turnover frequency and increased probability to
hydrogenate C=C. The combined experimental observations and DFT calculated results
depict that the pure metallic Co (111) with weak adsorption toward C=O favours the STH to
produce COL but unfavourable for efficient conversion, while the pure CoO (111) with
exceptionally strong adsorption toward CAL could lead to decrease in both COL selectivity
and CAL conversion efficiency. That is, for such core-shell composite cobalt nanoparticulate
catalysts, an optimal CoO composition is required to simultaneously achieve efficient
x
conversion and high selectivity.
In summary, we demonstrated the use of an ultrasonic-assisted carbothermal reduction
method to controllably synthesise the core-shell structured CoO @Co NPs based catalyst. The
x
resultant catalyst possesses superior performance toward selective transfer hydrogenation of a
wide spectrum of α,β-unsaturated aldehydes to corresponding unsaturated alcohols.
Importantly, we depict the need of an optimal CoO composition to simultaneously achieve
x
efficient conversion and high selectivity.
Supporting Information
Supporting Information is available from the Wiley Online Library or from the author.
Acknowledgements
This work was financially supported by the Natural Science Foundation of China (Grant No.
5
1432009, 51871209 and 51902311), the Postdoctoral Science Foundation of China (Grant
No. 2019M652223).
Conflicts of interest
There are no conflicts to declare.
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))
1
3
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ChemCatChem
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A facile ultrasonic-assisted carbothermal reduction method is innovatively utilized to prepare
core-shell structured CoO @Co nanoparticle catalyst as high performance selective transfer
x
hydrogenation catalyst to convert α,β-unsaturated aldehydes into corresponding unsaturated
alcohols with over 90% selectivity.
+
+
*
*
Wanbing Gong, Miaomiao Han, Chun Chen, Yue Lin, Guozhong Wang, Haimin Zhang
*
and Huijun Zhao
CoO @Co Nanoparticle-based Catalyst for Efficient Selective Transfer Hydrogenation of α,β-
x
Unsaturated Aldehydes
TOC figure
1
6
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