Calcination Atmosphere Regulated Morphology and Catalytic Performance of Pt/SiO2 in Gas-phase Oxidative Dehydrogenation of KA-oil

Article abstract of DOI:10.1002/cctc.201801279

It is industrially attractive to produce cyclohexanone directly from gas-phase oxidative dehydrogenation (ODH) of KA-oil (a mixture of cyclohexanone and cyclohexanol) since extra alcohol-ketone separation process can be potentially omitted. Herein, by simply tuning the calcination atmosphere of Pt/SiO₂, we successfully regulated the morphology of Pt nanoparticles and optimized their catalytic performance in ODH of KA-oil. Pt/SiO₂ calcined in O₂ atmosphere showed a cube-like morphology and achieved a 78.1 % cyclohexanone yield at 170 °C, which surpassed its counterpart calcined in H₂ and most of the reported catalysts. Further experimental and theoretical calculation results indicated that cubic Pt nanoparticles possessed stronger adsorption ability to cyclohexanol and therefore performed better in ODH of KA-oil.

Full text of DOI:10.1002/cctc.201801279

DOI: 10.1002/cctc.201801279
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Calcination Atmosphere Regulated Morphology and
Catalytic Performance of Pt/SiO in Gas-phase Oxidative
2
Dehydrogenation of KA-oil
+
[a]
+ [b]
[a]
[a]
[a]
[a]
Wei Hong , Zhi-Qiang Wang , Shihui Zou,* Yuheng Zhou, Linfang Lu, Qiuyue Zhou,
[b]
[a]
Xue-Qing Gong,* and Jie Fan*
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It is industrially attractive to produce cyclohexanone directly
from gas-phase oxidative dehydrogenation (ODH) of KA-oil (a
mixture of cyclohexanone and cyclohexanol) since extra
alcohol-ketone separation process can be potentially omitted.
Herein, by simply tuning the calcination atmosphere of Pt/SiO2,
we successfully regulated the morphology of Pt nanoparticles
and optimized their catalytic performance in ODH of KA-oil. Pt/
SiO calcined in O atmosphere showed a cube-like morphology
2
2
and achieved a 78.1% cyclohexanone yield at 170°C, which
surpassed its counterpart calcined in H and most of the
2
reported catalysts. Further experimental and theoretical calcu-
lation results indicated that cubic Pt nanoparticles possessed
stronger adsorption ability to cyclohexanol and therefore
performed better in ODH of KA-oil.
Introduction
none further decreases the activity (entry 6 and 9 in Table 1). To
this end, developing advanced catalysts that can strengthen the
adsorption of cyclohexanol and weaken the adsorption of
cyclohexanone has become a focus in this area.
Cyclohexanone is a very important and versatile intermediate in
current chemical industrial practices as it is frequently used in
the production of ɛ-caprolactam for the manufacture of nylon-
It has long been recognized that the morphology (exposed
crystal planes) of the active nanoparticles is an important factor
affecting the adsorption ability and catalytic performance of the
[1]
6
.
Industrially, cyclohexanone is mainly produced in the form
of KA-oil (a mixture of cyclohexanone and cyclohexanol) by
selective oxidation of cyclohexane. Due to the close boiling
[2]
[4]
catalyst. For instance, Lee et al. found that the isomerization of
points of cyclohexanone and cyclohexanol (155°C vs. 161°C),
trans-2-butene to cis-2-butene was promoted by Pt(111) faces
due to the extra stability of cis-2-butene on hydrogen-saturated
Pt(111) surfaces. Considering Pt was recently reported as an
an energy-intensive distillation separation is generally required
[3]
[4c]
to produce pure cyclohexanone. For the purpose of simplify-
ing operations and saving energy, it is highly attractive to
develop gas-phase oxidative dehydrogenation (ODH) of KA-oil
that can potentially achieve a 100% yield of cyclohexanone.
However, the reported catalytic systems are still far from
affording a cyclohexanone yield (~100%) that is able to omit
the alcohol-ketone separation process. Typically, the reported
conversion in ODH of cyclohexanol is less than 80% and a high
reaction temperature is generally required (typically 230–340°C,
see Table 1 below). When KA-oil is used as the substrate, the
competitive adsorption between cyclohexanol and cyclohexa-
[5]
efficient catalyst for selective oxidation of KA-oil, we reasoned
that a precise control over the morphology might be able to
optimize the adsorption of cyclohexanol/cyclohexanone and
therefore further improve the catalytic performance of Pt in
ODH of KA-oil.
[6]
Unlike the sophisticated colloid synthesis, in this work, the
morphology of Pt nanoparticles (PtNPs) was tuned simply by a
calcination of Pt/SiO in different atmospheres. The absence of
2
ligand modification provided a clean surface to investigate the
correlation between Pt facets and activity. The cube-like PtNPs
obtained by calcinating Pt/SiO in O (denoted as Pt/SiO -O)
2
2
2
exhibited a much better catalytic performance in ODH of KA-oil
than round-edged PtNPs, which were produced by calcinating
Pt/SiO in H (denoted as Pt/SiO -H). Pt/SiO -O presented a yield
of cyclohexanone as high as 78.1% at 170°C, exceeding most of
the reported catalysts (Table 1). Combining the extensive kinetic
data with theoretical calculations, we successfully revealed the
relationship between the morphology of PtNPs and the
adsorption ability and catalytic performance of PtNPs.
+
[a] W. Hong, Dr. S. Zou, Y. Zhou, Dr. L. Lu, Q. Zhou, Prof. J. Fan
Key Lab of Applied Chemistry of Zhejiang Province
Department of Chemistry
Zhejiang University
Hangzhou 310027 (P.R. China)
E-mail: jfan@zju.edu.cn
xueshan199@163.com
b] Z.-Q. Wang, Prof. X.-Q. Gong
Key Laboratory for Advanced Materials
Centre for Computational Chemistry and Research Institute of Industrial
Catalysis
2
2
2
2
+
[
East China University of Science and Technology
Shanghai, 200237, (P.R. China)
E-mail: xgong@ecust.edu.cn
Results and Discussion
+
[
] These authors contributed equally to this work.
Shape-controlled synthesis of metal nanocatalysts is a very hot
topic in the catalysis research. In addition to the classic colloid
Supporting information for this article is available on the WWW under
https://doi.org/10.1002/cctc.201801279
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[
a]
Table 1. Gas-phase oxidative dehydrogenation of cyclohexanol or KA-oil to cyclohexanone.
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Entry
Catalyst
Substrate
Oxidant
Temperature [°C]
Cyclohexanol conversion [%]
Cyclohexanone yield [%]
Reference
1
2
3
4
5
6
7
8
ETS-10
Ag
Ag/ZFC
Mn/MCM-41
CoO/Ag
Au/SiO2
cyclohexanol
cyclohexanol
cyclohexanol
cyclohexanol
cyclohexanol
cyclohexanol
cyclohexanol
KA-oil
Air
Air
250
340
320
250
280
230
240
200
230
170
170
49.7
53
38
52
79
35.7
10.2
74
11.4
85.4
45.3
33.6
51
23
39
75
35.7
10.2
74
11.4
78.1
37.4
[1c]
[10]
[11]
[12]
[13]
[14]
[15]
[5]
O
2
:N
2
(1:15)
Air
O
2
:N
2
(1:7.45)
O2
AuNi/SiO
Pt/CuClP
2
O
2
Air
[b]
9
10
Au/SiO
Pt/SiO -O
2
KA-oil
KA-oil
KA-oil
O
2
This work
This work
This work
[
[
c]
c]
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Air
Air
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1
1
Pt/SiO
2
-H
[a] KA-oil consists of 1:1 weight ratio of cyclohexanone and cyclohexanol. [b] Reaction condition: 1 wt% Au loading, 0.1 g catalyst mixed with 1.2 g quartz
sand, O =4 mLmin , KA-oil=0.4 mLh . [c] Reaction condition: 1 wt% Pt loading, 0.2 g catalyst mixed with 1.2 g quartz sand, air=16 mLmin , KA-oil=
2
À 1
À 1
À 1
À 1
0
.4 mLh . The carbon balance is >95%.
[6]
synthesis, it is proposed recently that gas molecules adsorbed
cubic shapes, 34% irregular shapes and only 15% spherical
shapes. The high-resolution TEM (HRTEM) image (Figure 1b) of
[7]
on specific crystal faces can also induce a shape evolution.
While environmental transmission electron microscopy (ETEM)
studies and theoretical calculations have verified the feasibility
few studies have utilized it to rationally
design practical catalysts. Considering the different adsorption
behavior of O2 and H2 on Pt surface, we reason that
calcinating Pt precursors in O and H will produce different
a cube-like particle of Pt/SiO À O shows continuous lattice
2
fringes with a lattice spacing of 0.197 nm, which corresponds to
the (200) plane of Pt. The spots in the fast Fourier transform
[7a,8]
of this approach,
(FFT) pattern also confirm that PtNPs in Pt/SiO À O are single-
2
[8]
[9]
crystal Pt nanocubes (Figure 1b inset). In contrast, more
round-edged PtNPs are observed in Pt/SiO À H sample (Fig-
2
2
2
shaped PtNPs.
ure 1c and Figure S2). Pt particles in Pt/SiO À H consist of 83%
2
Figure 1a shows a typical TEM image of Pt/SiO À O. Clearly,
spherical shapes, 12% irregular shapes and only 5% cubic
shapes. The lattice fringes of a spherical Pt particle show an
interplanar spacing of 0.224 nm, corresponding to the (111)
plane of Pt (Figure 1d). The different morphology of PtNPs
obtained by calcinations can be well explained by the previous
reported theoretical calculations and ETEM studies. Yuan et al.
2
some cube-like Pt particles have formed after calcination in O
2
atmosphere (see Figure S1 for more TEM images). Statistical
analysis suggests that Pt particles in Pt/SiO À O consist of 51%
2
proposed that low coordinated Pt(100) surface binds O more
strongly compared to the closely packed Pt(111) surface. The
2
[
8a]
stronger adsorption of O might therefore lead to the extension
2
[7a]
of (100) faces and the shrink of (111) faces. On the other
[8b]
hand, H prefers to adsorb on Pt(111) surface, which might
2
consequently produce rounded shapes or truncated octahedral
[7a]
shapes.
Unlike the different morphology, Pt/SiO samples calcined
2
at different atmospheres show similar XRD patterns (Figure S3).
The characteristic diffraction peaks at 2θ=39.8, 46.3 and 67.5°
can be readily assigned to (111), (200), and (220) of Pt (PDF#04-
0
802). The average Pt particle size of Pt/SiO -O (21.5 nm) is
2
close to that of Pt/SiO -H (17.8 nm), indicating that the different
2
calcination atmospheres won’t significantly change the average
particle size. CO pulse chemisorption results indicate that the Pt
dispersions of Pt/SiO -O and Pt/SiO -H are similar (3.52% vs.
2
2
3
.71%, Table 2). X-ray photoelectron spectroscopy (XPS) analy-
sis shows no visible signals of chlorine (Figure S4), suggesting
that H PtCl is completely decomposed into PtNPs. Besides, Pt
2
6
0
4
f XPS data (Figure S5) also confirm that Pt is the major phase
in both samples. A small amount of Pt species is detected in
4
+
Figure 1. TEM images of Pt/SiO
statistic distribution of different shaped Pt NPs. HRTEM images of Pt particles
of Pt/SiO
2
À O (a) and Pt/SiO À H (c). The insets show the
2
fresh Pt/SiO À O, likely due to the formation of PtO on the
2
2
surface of PtNPs. This species can be easily reduced by
cyclohexanol and therefore disappears in the spent catalyst.
Taking all together, Pt/SiO À O and Pt/SiO À H provide excellent
2
À O (b) and Pt/SiO À H (d). The insets show FFT patterns of the
2
lattice images in (b) and (d). The squares, circles and triangles in the figures
represent the cubic, spherical and irregular shapes, respectively.
2
2
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significant catalytic difference. Besides, as the temperature
2 2
Table 2. Characterization of Pt/SiO -O and Pt/SiO -H catalysts.
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increases from 165 to 180°C, the cyclohexanol conversion of Pt/
Catalyst
Pt surface area
Dispersion (D)
[%]
Particle size, d [nm]
Chemisorption
2
À 1 [a]
[a]
[b]
[c]
SiO À H increases from 29.8% to 64.3%. Further increasing the
[
m gcat.
]
XRD
2
temperature to 185°C, however, slightly decreases the con-
version of cyclohexanol, likely due to the competitive adsorp-
tion between cyclohexanol and cyclohexanone. The cyclo-
Pt/SiO -O
Pt/SiO -H
2
2
0.087
0.092
3.52
3.71
32.1
30.4
21.5
17.8
[
16]
[a] Estimated from CO pulse chemisorption; [b] Based on d (nm)=1.13/D.
c] Based on the Scherrer equation.
hexanone selectivity of Pt/SiO À O is always about 10% higher
2
[
than that of Pt/SiO À H in the temperature range of 165–185°C,
2
supporting an inference that Pt/SiO À O favors the adsorption of
2
cyclohexanol over cyclohexanone than Pt/SiO À H.
2
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models to investigate the morphology effect on their catalytic
performances.
To verify this inference, we conducted comparison studies
of the reaction kinetic on Pt/SiO À O and Pt/SiO À H. As shown in
2
2
Figure 2a shows the catalytic activity and selectivity of Pt/
SiO À O and Pt/SiO À H in ODH of KA-oil. In all cases, the main
Figure 2b, the apparent activation energies of cyclohexanol
ODH reaction over Pt/SiO À O and Pt/SiO À H are close (61.0 vs.
2
2
2
2
À 1
by-product is CO . Other by-products are benzene, cyclohexene
56.4 kJmol ), implying identical reaction pathways in these
2
and 2-cyclohexen-1-one and the selectivities of these com-
two cases. Additionally, O partial pressure experiments suggest
2
pounds are all less than 0.1%. Notably, Pt/SiO À O shows very
that there is only a small change of the apparent reaction order
2
good cyclohexanol conversion and cyclohexanone selectivity at
of O2 molecules on Pt/SiO À O and Pt/SiO À H (0.82 vs. 0.77,
2
2
full temperature ranges (165–185°C). The cyclohexanone yield
Figure 2c). However, the apparent reaction order of cyclo-
of Pt/SiO -O reaches 78.1% even at a temperature as low as
hexanol on Pt/SiO À O is 0.13 (Figure 2d), obviously smaller than
2
2
1
70°C, surpassing most of the literature results (Table 1). It is
that on Pt/SiO À H (0.36). Based on the classic theory, smaller
2
important to highlight that at 165°C, the cyclohexanone yield
reaction order indicates stronger adsorption on the surface of
[17]
of Pt/SiO À O is about 3 times larger than that of Pt/SiO À H
catalyst.
Therefore, we come to the conclusion that O2
2
2
(
74.3% vs. 24.2%), which clearly indicates the great influence of
adsorption is not the decisive factor for the activity difference,
whereas cyclohexanol adsorption is the key point.
the calcination atmosphere. The different morphology of PtNPs
induced by the calcination atmosphere might account for this
Figure 2. (a) Cyclohexanol conversion and cyclohexanone selectivity of Pt/SiO -O and Pt/SiO -H in ODH of KA-oil. Reaction condition: 0.2 g catalyst mixed with
2
2
À 1
À 1
1
.2 g quartz sand, air=16 mLmin , KA-oil=0.4 mLh . The carbon balance is >95%. (b) The Arrhenius plots of Pt/SiO
cyclohexanol. The influence of O (c) and cyclohexanol (d) partial pressure on catalytic activity of Pt/SiO
À O and Pt/SiO
activity is calculated based on the mole number of converted cyclohexanol molecules. Cyol represents cyclohexanol.
2
À O and Pt/SiO
2
À H in ODH of
2
2
2
À H in ODH of cyclohexanol. The
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Figure 3. (a) TPD curves of cyclohexanol and cyclohexanone on SiO support, Pt/SiO À O and Pt/SiO À H. (b) FID peaks of collected species desorbed in the
2
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high-temperature region of TPD experiments. (c) The corrected amount of chemisorbed cyclohexanol and cyclohexanone on Pt/SiO
and cyone represent cyclohexanol and cyclohexanone, respectively.
2
À O and Pt/SiO À H. Cyol
2
Temperature-programmed desorption (TPD) measurements
were then carried out to quantify the amount of chemisorbed
cyclohexanol and cyclohexanone on Pt/SiO À O and Pt/SiO À H.
15.1�2.5 nm (longer diagonal, Figure 4d), containing about
74% octahedrons (consisting of only Pt(111)). HRTEM images in
Figure 4b and 4e show the lattice spacing of 0.199 nm and
0.230 nm, corresponding to the typical (200) and (111) plane of
Pt cubes and octahedrons, respectively. The synthesized cubic
and octahedral nanoparticles were loaded onto SiO2 by a
colloid deposition method, followed by a thermal treatment at
250°C. As shown in Figure 4c and 4f, the PtNPs basically
maintain the sizes and the desired shapes. XRD patterns
(Figure S6) indicate that there is no detectable KCl or NaCl
residual from synthesis processes in these two catalysts.
2
2
As shown in Figure 3a, TPD curves of cyclohexanol- or cyclo-
hexanone-adsorbed Pt/SiO catalysts show two distinct signals.
2
The one located at low-temperature region belongs to the
physical adsorption and the other located at high-temperature
region is assigned to the chemisorbed molecules which have
stronger interaction with Pt/SiO catalysts. Control experiments
2
show that SiO2 support seldom chemisorbs cyclohexanol or
cyclohexanone. Thus, the chemisorbed molecules are contrib-
uted by PtNPs. To further understand the TPD data, we
collected the desorbed species in the high-temperature region
and analyzed them with GCÀ FID and GCÀ MS. As shown in
Figure 3b, benzene, cyclohexene, phenol and 1,1-diethoxy-2-
hexene (possibly deriving from 2-hexenal and ethanol) in
addition to cyclohexanol and cyclohexanone are detected,
indicating that the chemisorbed cyclohexanol and cyclohexa-
none are decomposed on Pt surfaces at high temperatures
before desorbed into gas phase. Thus, in this situation, the
desorption temperature cannot stand for the adsorption
strength. By adding together the amount of all products, we
could infer the initial adsorption amount of cyclohexanol or
cyclohexanone. As shown in Figure 3c, the initial adsorption
The catalytic activity and selectivity of Pt cubes/SiO and Pt
2
octahedrons/SiO in ODH of KA-oil are shown in Figure 5a. The
2
cyclohexanone selectivity of cubes is close to that of octahe-
drons, whereas the cyclohexanol conversion of cubes is higher
than that of octahedrons by about 25–35% in the temperature
range of 165–185 °C, in good agreement with the catalytic
performances of Pt/SiO À O and Pt/SiO À H. Moreover, the
2
2
apparent reaction order of cyclohexanol on Pt cubes/SiO is
2
smaller than that on Pt octahedrons/SiO as expected (0.26 vs.
2
0.41, Figure 5b), suggesting stronger cyclohexanol adsorption
ability of cubes. A similar situation is observed in the apparent
reaction order of O molecules on cubes and octahedrons (0.59
2
vs. 0.79, Figure 5c). Furthermore, TPD measurements (Figure S7
À 1
amount of cyclohexanol on Pt/SiO À O (47.0 mgg ) is obvi-
and 5d) suggest the initial adsorption amount of cyclohexanol
2
Pt
À 1
À 1
ously larger than that on Pt/SiO À H (29.0 mgg ), in good
on cubes (40.1 mggPt ) is not only larger than that on
2
Pt
À 1
agreement with their activity difference. Moreover, on Pt/
octahedrons (28.0 mggPt ) but also larger than the initial
À 1
SiO À O, the initial adsorption amount of cyclohexanol is 1.69
adsorption amount of cyclohexanone on cubes (26.5 mggPt ).
2
À 1
times as large as that of cyclohexanone (27.8 mgg ), which
This result provides another convincing evidence that cyclo-
hexanol can be adsorbed on cubic Pt particles more easily,
which leads to a better catalytic performance in ODH of KA-oil.
To rationalize the experimental observations, we further
performed density functional theory (DFT) calculations to
determine the adsorption properties of cyclohexanol and cyclo-
hexanone at PtNPs. The cubic and octahedral PtNPs were
modelled by Pt(100) and Pt(111) facets, respectively. As shown
in Figure 6, the adsorption energy of the most stable binding
configuration for cyclohexanol on Pt(100) is obviously higher
Pt
further explains its excellent catalytic performance in ODH of
KA-oil.
To further prove that the catalytic difference between Pt/
SiO À O and Pt/SiO À H is caused by the different morphology,
2
2
PtNPs with specific shapes were synthesized using reported
[18]
methods. As shown in Figure 4a, the synthesized cubic PtNPs
have an average size of 15.3�1.7 nm (diagonal), containing
about 68% cubes (consisting of only Pt(100)). On the other
hand, the synthesized octahedral PtNPs have an average size of
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Figure 4. TEM images of cubic particles (a), cubes/SiO
a cube (b) and an octahedron (e). The insets show FFT patterns of the lattice images in (b) and (e).
2 2
after calcination (c), octahedral particles (d) and octahedrons/SiO after calcination (f). HRTEM images of
Figure 5. (a) Cyclohexanol conversion and cyclohexanone selectivity of Pt cubes/SiO
2
and Pt octahedrons/SiO
catalyst mixed with 1.2 g quartz sand, air=16 mLmin , KA-oil=0.4 mLh . The main byproduct is CO and the carbon balance is >95%. The influence of
cyclohexanol (b) and O (c) partial pressure on catalytic activity in ODH of cyclohexanol. The activity is calculated based on the mole number of converted
cyclohexanol molecules. (d) The amount of chemisorbed cyclohexanol and cyclohexanone on Pt cubes/SiO and Pt octahedrons/SiO
2
in ODH of KA-oil. Reaction condition: 0.2 g
À 1
À 1
2
2
2
2
.
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than on Pt(111), being consistent with the result obtained from
partial pressure experiments. Besides, the adsorption energies
of the most stable binding configurations for cyclohexanone
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(Figure S8) on both Pt(100) and Pt(111) are smaller than those
for cyclohexanol, which is consistent with the relative good
selectivity of cyclohexanone on Pt cubes/SiO and Pt octahe-
2
drons/SiO (Figure 5a).
2
Taking all these results together, both the experimental
data and theoretical calculations show that cubic PtNPs possess
stronger adsorption ability to cyclohexanol than octahedral
PtNPs and therefore display better catalytic activity in ODH of
1
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1
1
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KA-oil. In the case of Pt/SiO À O, many cube-like particles have
2
formed after calcination in O atmosphere and these particles
2
help to improve the catalytic performance as a consequence.
Moreover, the catalytic stability of Pt/SiO À O catalyst was
2
investigated under the applied reaction condition. As shown in
Figure 7a, the cyclohexanone selectivity is maintained at about
8
8% all the time, whereas the cyclohexanol conversion
Figure 6. Calculated binding configurations and corresponding adsorption
energies of the cyclohexanol at Pt(100) and Pt(111). Pt atoms are in blue, C
in gray, O in red and H in white. Cyol represents cyclohexanol.
decreases from 87.6% to 72.1% (17.7% activity loss) after a
100-hour test. XRD analysis in Figure 7b shows that the average
particle size of PtNPs after reaction is nearly the same as that of
fresh catalyst. Figure 7c displays a TEM image of spent Pt/SiO2-
O catalyst. As we can see, the cube-like PtNPs formed by
calcination in O2 atmosphere are quite stable during low-
temperature gas-phase ODH reaction. Thus, the deactivation is
than that on Pt(111) (1.60 eV vs. 1.21 eV). This result clearly
indicates stronger chemisorption of cyclohexanol on Pt(100)
Figure 7. (a) Long-term stability test of Pt/SiO À O catalyst. Reaction condition: 0.2 g catalyst mixed with 1.2 g quartz sand, temperature=175°C,
2
À 1
À 1
air=16 mLmin , KA-oil=0.4 mLh . (b) XRD patterns of fresh and spent Pt/SiO
2
À O catalyst. (c) TEM image of spent Pt/SiO
2
À O catalyst. The squares, circles
and triangles in the figure represent the cubic, spherical and irregular shapes, respectively. (d) TGA curve of spent Pt/SiO
2
À O catalyst. Test condition: O
2
À 1
À 1
flow=50 mLmin , heating rate=10°Cmin
.
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not likely caused by the change of size or morphology. Further
thermogravimetric analysis (TGA) in Figure 7d indicates that
there are 2.5 wt% carbon species formed, which are believed to
result in a mild deactivation. Strategies that can further improve
the yield of cyclohexanone and the catalytic stability merit
further study beyond the scope of this paper.
Finally, the pale-yellow powder was calcined in H or O for 5 h,
2 2
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
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0
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0
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denoted as Pt/SiO À H and Pt/SiO À O, respectively. Due to the high
2
2
thermal decomposition temperature of PtCl (570 C under non-
reductive atmosphere), the calcination temperature was set to
°
2
[21]
600
°
C.
Synthesis of Pt cubes. The synthesis of Pt cubes was performed
[4e,18a]
using TTAB as a protector and NaBH as a reductant.
A solution
containing 9.3 mL of deionized water, 7.5 mL of 0.4 M TTAB
aqueous solution and 2.0 mL of 15.0 mM K PtCl aqueous solution
4
2
4
Conclusions
was introduced in a 50 mL vial. The vial reactor was kept at 50°C
with magnetic stirring. After the solution became clear, 1.2 mL of a
1
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fresh 0.75 M NaBH aqueous solution was added. The vial reactor
In summary, we have successfully regulated the morphology of
PtNPs by tuning the calcination atmosphere and applied them
in gas-phase ODH of KA-oil. The strong interaction between O2
and Pt(100) plane ensures the production of cube-like PtNPs by
calcinating Pt/SiO in O atmosphere. The cyclohexanone yield
4
kept connected to the open air for 10 min and was then sealed for
6 h. The product was centrifuged at 3 krpm for 30 min. The
supernatant solution was further centrifuged at 14 krpm for 10 min.
The black precipitate was redispersed in deionized water and the
solution was centrifuged at 14 krpm for 10 min. Finally, the
precipitate was collected and redispersed in deionized water.
2
2
of Pt/SiO À O catalyst can reach up to 78.1% at a relatively low
2
temperature of 170°C, surpassing most of the reported results.
Experimental and theoretical calculation results reveal that
these cube-like PtNPs help to strengthen the adsorption of
cyclohexanol, which is vitally important to the outstanding
catalytic performance in ODH of KA-oil. Though the current
catalytic system is still far from achieving a 100% cyclo-
hexanone yield to omit extra alcohol-ketone separation process,
it takes a valuable step forward. It is expected that the outcome
of this work will help to accelerate the design of more efficient
and durable catalysts not only for gas-phase ODH of KA-oil but
Synthesis of Pt octahedrons. The Pt octahedrons were synthesized
by the reduction of H PtCl by EG in the presence of PVP and
2
6
[18b]
NaNO
under air.
Briefly, 1 mL of 80 mM H PtCl solution in EG
3
2 6
was rapidly added to 7 mL EG (kept at 160°C) which contained
both PVP and NaNO . The final solution consisted of 10 mM H PtCl ,
3
2
6
30 mM PVP and 55 mM NaNO . After reacting for 20 min, the
3
product was precipitated by adding 24 mL of acetone and was
then washed twice by a mixed solvent consisting of 5 mL of
ethanol and 15 mL of n-hexane. Finally, the product was redis-
persed in ethanol using sonication.
Preparation of 1wt% Pt cubes/SiO and 1wt% Pt octahedrons/
2
[4b,e,19]
also for other structure-sensitive reactions.
SiO . 0.5 g of silica nanospheres were added to Pt colloidal solution
2
containing 5 mg Pt (verified by inductively coupled plasma-atomic
emission spectrometry). The mixture was stirred vigorously at room
temperature until the solvent was evaporated to dryness and was
then transferred into a 65°C oven for 3 h. In order to minimize the
Experimental Section
contamination on the surface of Pt particles and preserve the
desired particle shape simultaneously, the grey powder was
Materials and Reagents
[
4b]
calcined at 250°C in O for 1 h and then in H for another 1 h.
2
2
H
PtCl
·6H O (AR), NaNO (AR), NaBH (98%), tetraethyl orthosilicate
6 2 3 4
2
The oxidation-reduction cycle was repeated twice.
(TEOS, AR), ethylene glycol (EG, AR), cyclohexanone (AR) and
ammonium hydroxide aqueous solution (25%) were purchased
from Sinopharm Chemical Reagent Co., Ltd. Poly(vinylpyrrolidone)
Characterization
(
(
PVP, M =58 000) and tetradecyltrimethylammonium bromide
W
TTAB, 99%) were purchased from Aladdin. K PtCl (99.9%) was
2
4
Transmission electron microscopy (TEM) images were recorded on
the Hitachi HT-7700 microscope operated at 100 kV. High-resolu-
tion TEM images were recorded on the FEI Tecnai G2 F20 S-TWIN
microscope operated at 200 kV. Wide-angle X-ray diffraction (XRD)
patterns were recorded on a Rigaku Ultimate IV diffractometer
purchased from Alfa Aesar. Cyclohexanol (AR,ꢀ98.5%) was ob-
tained from Macklin. KA-oil consisted of 1:1 weight ratio of
cyclohexanone (AR) and cyclohexanol (AR,ꢀ98.5%). All chemicals
were used without further purification.
using Cu K radiation. The average particle size was derived from
α
the Scherrer equation based on the peak width of the Pt(111)
reflection. Thermogravimetric analysis (TGA) curve was recorded
with STA409PC TG-DTA/DSC analyzer. The temperature-pro-
Catalysts preparation
Synthesis of silica nanospheres. Silica nanospheres were synthe-
[20]
grammed desorption (TPD) curves were recorded using GC-FID. N
was used as carrier gas and was controlled at 100 mLmin . The
prepared Pt/SiO2 catalysts were pretreated by cyclohexanol or
2
sized using a classic Stöber method.
Typically, 18 mL of
À 1
ammonium hydroxide aqueous solution (25%) and 6 mL of
deionized water were mixed with 360 mL of ethanol, followed by
vigorous stirring for 0.5 h at 25°C. Subsequently, 13.8 mL of TEOS
was added to this solution. The mixture was stirred vigorously for
cyclohexanone supplied through a syringe pump at a speed of
À 1
0
1
.6 mLh at 165°C for 1 h. Then, N continued to sweep at
2
À 1
00 mLmin for 2 h to remove the weakly adsorbed species.
Subsequently, 10 mg of the pretreated sample was placed in a
6
6
h and was then centrifuged, washed with ethanol and dried at
5°C. The obtained silica nanospheres were calcined at 600°C in
quartz tube fixed by silica wool. The sample was swept by N
at
2
dry air for 5 h to remove residual organic groups and most of
surface hydroxyl groups before use.
À 1
room temperature at a speed of 200 mLmin . The sweeping N2
flow was then introduced into GC-FID. After the baseline of GC-FID
became stable, the TPD was carried out from 25 to 690°C with a
Preparation of 1wt% Pt/SiO . 3.32 mL of 7.72 mM H PtCl ·6H O
2
2
6
2
À 1
ethanol solution was mixed with 0.5 g of silica nanospheres at
room temperature. The mixture was evaporated slowly with
vigorous stirring and was then transferred into a 65°C oven for 3 h.
heating rate of 5°C min . For the offline collection experiment,
2
.5 g of the pretreated sample (40–100 mesh) and a cold trap filled
with ethanol were used. The collection started from 290°C to
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5
20°C and held at 520°C for 1 h. Chlorobenzene was used as the
along with a 2×2×1 Monkhorst-Pack grid for the different surface
slabs.
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internal standard for quantitative analysis of the desorbed species.
Catalytic Reaction
Acknowledgements
The gas-phase oxidative dehydrogenation (ODH) of KA-oil was
performed within an electronically controlled furnace in a fixed bed
vertical glass reactor (length=250 mm, inner diameter=12 mm),
fitted with a glass frit carrying the catalyst mixed with quartz sand.
Standard air (21% O and 79% N ) was used as oxidant. The air
This work was supported by National Natural Science Foundation
of China (91545113, 91545103, 21573067), China Postdoctoral
Science Foundation (512200-X91701), Shell Global Solutions
International B. V. (PT71423, PT74557), Fok Ying Tong Education
Foundation (131015) and the Fundamental Research Funds for
the Central Universities (2014XZZX003-02).
2
2
À 1
stream (16 mLmin ) was controlled by a mass flow instrument and
the liquid reagent (0.4 mLh ) was supplied through a syringe
1
1
1
1
1
1
1
1
1
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À 1
pump. Liquid vaporization occurred on the reactor wall prior to the
catalytic bed. The reaction ran for 1.5 h to reach equilibrium before
every sampling. Afterwards, liquid- and gas-phase products were
collected at the same time. Liquid-phase products were analyzed
by GC-FID equipped with a 30 m SE-54 column using 2 M Conflict of Interest
triethylene glycol dimethyl ether in acetone as internal standard.
Gas-phase products were analyzed by GC-TCD equipped with a 1 m
The authors declare no conflict of interest.
TDX-01 column and CO2 was the only gas-phase product.
Conversion and selectivity were calculated combing both liquid-
and gas-phase analytic results.
Keywords: Pt/SiO2 · Calcination atmosphere · Morphology ·
Oxidative dehydrogenation · KA-oil
Partial Pressure Experiments
The catalytic bed temperature was kept at 170°C during partial
pressure experiments. The charging rate of gas stream and cyclo-
hexanol were controlled by a mass flow instrument and a syringe
pump, respectively. For the control of O partial pressure, N was
[1] a) B. M. Nagaraja, V. Siva Kumar, V. Shashikala, A. H. Padmasri, S.
Sreevardhan Reddy, B. David Raju, K. S. Rama Rao, J. Mol. Catal. A 2004,
223, 339–345; b) S. A. Chavan, D. Srinivas, P. Ratnasamy, J. Catal. 2002,
212, 39–45; c) A. Valente, Z. Lin, P. Brandão, I. Portugal, M. Anderson, J.
Rocha, J. Catal. 2001, 200, 99–105; d) H. Liu, T. Jiang, B. Han, S. Liang, Y.
Zhou, Science 2009, 326, 1250–1252.
2
2
À 1
used as balance gas and total flow rate was kept at 16 mLmin , of
À 1
which the air flow rate (0 to 16 mLmin ) was adjusted to certain
À 1
ratios with cyclohexanol (0.4 mLh ). For the control of cyclo-
hexanol partial pressure, air flow rate was fixed at 16 mLmin
[2] a) X. Fang, Z. Yin, H. Wang, J. Li, X. Liang, J. Kang, B. He, J. Catal. 2015,
À 1
3
29, 187–194; b) A. A. Alshaheri, M. I. M. Tahir, M. B. A. Rahman,
while the charging rate of cyclohexanol was adjusted (0 to
T. B. S. A. Ravoof, T. A. Saleh, Chem. Eng. J. 2017, 327, 423–430; c) R. Raja,
G. Sankar, J. M. Thomas, J. Am. Chem. Soc. 1999, 121, 11926–11927; d) Y.
Liu, H. Tsunoyama, T. Akita, S. Xie, T. Tsukuda, ACS Catal. 2011, 1, 2–6;
e) Z. Xiao, W. Zhan, Y. Guo, Y. Guo, X. Gong, G. Lu, Chin. J. Catal. 2016,
À 1
1
.2 mLh ). Product analysis was similar to the gas-phase ODH of
KA-oil.
3
7, 273–280.
[
3] a) K. Tan, K. Fujii, M. Nakamura, K. Hanada (Mitsubishi Kasei Corpo-
ration), US 5168983, 1992; b) C. L. Becker, J. D. Davis, J. M. Dakka, K. C.
Nadler (ExxonMobil Chemical Patents Inc.), US 9868687 B2, 2018.
DFT Calculations
Density functional theory (DFT) calculations were carried out using
[
22]
[4] a) Y. Zhou, Y. Zhu, Z. Q. Wang, S. Zou, G. Ma, M. Xia, X. Kong, L. Xiao,
X. Q. Gong, J. Fan, J. Am. Chem. Soc. 2017, 139, 13740–13748; b) I. Lee,
R. Morales, M. A. Albiter, F. Zaera, Proc. Natl. Acad. Sci. USA 2008, 105,
the Vienna Ab-initio Simulation Package (VASP).
polarized projector augmented wave (PAW) method
Perdew–Burke–Ernzerhof (PBE)
The spin-
[
23]
and the
electron exchange-correlation
functional of the generalized gradient approximation (GGA) were
applied in our calculations. The kinetic energy cut-off for the wave
function expanded in the plane-wave basis was set as 400 eV. To
optimize the structures, the calculation was performed until the
[
24]
15241–15246; c) I. Lee, F. Delbecq, R. Morales, M. A. Albiter, F. Zaera,
[25]
Nat. Mater. 2009, 8, 132–138; d) M. Englisch, A. Jentys, J. A. Lercher, J.
Catal. 1997, 166, 25–35; e) K. M. Bratlie, H. Lee, K. Komvopoulos, P. Yang,
G. A. Somorjai, Nano Lett. 2007, 7, 3097–3101.
5] A. M. Gill, C. S. Hinde, R. K. Leary, M. E. Potter, A. Jouve, P. P. Wells, P. A.
Midgley, J. M. Thomas, R. Raja, ChemSusChem 2016, 9, 423–427.
6] a) T. S. Ahmadi, Z. L. Wang, T. C. Green, A. Henglein, M. A. El-Sayed,
Science 1996, 272, 1924–1925; b) A. R. Tao, S. Habas, P. Yang, Small
[
[
À 1
maximum force upon each relaxed atom was less than 0.05 eVÅ .
The vacuum height was set as 15 Å to eliminate the interaction
between neighboring slabs.
2
008, 4, 310–325; c) J. Chen, B. Lim, E. P. Lee, Y. Xia, Nano Today 2009, 4,
81–95; d) Z. Peng, H. Yang, Nano Today 2009, 4, 143–164.
The adsorption energy (Eads) was calculated as follows [Eq. (1)]:
[
7] a) M. Cabié, S. Giorgio, C. R. Henry, M. R. Axet, K. Philippot, B. Chaudret,
J. Phys. Chem. C 2010, 114, 2160–2163; b) A. S. Ramachandran, S. L.
Anderson, A. K. Datye, Ultramicroscopy 1993, 51, 282–297; c) G.
Rupprechter, H.-J. Freund, Top. Catal. 2000, 14, 3–14; d) M. McLean, H.
Mykura, Surf. Sci. 1966, 5, 466–481; e) F. Mittendorfer, N. Seriani, O.
Dubay, G. Kresse, Phys. Rev. B 2007, 76, 233413; f) H. Graoui, S. Giorgio,
C. R. Henry, Surf. Sci. 1998, 417, 350–360; g) S. Giorgio, S. Sao Joao, S.
Nitsche, D. Chaudanson, G. Sitja, C. R. Henry, Ultramicroscopy 2006, 106,
Eads ¼ À ðEtotalÀ EsubstrateÀ Egas-phase adsorbateÞ
ð1Þ
where Etotal is the calculated total energy of the adsorption system,
Esubstrate is the energy of the clean substrate and Egas-phase adsorbate is the
energy of the gas-phase molecule.
503–507.
[8] a) W. Yuan, Y. Jiang, Y. Wang, S. Kattel, Z. Zhang, L.-Y. Chou, C.-K. Tsung,
To study the adsorption of cyclohexanol and cyclohexanone on Pt
111) and Pt(100) surfaces, we used the following models: a 4×4
surface cell was used to construct a six-layer Pt(111) and Pt(100)
slab, the top three layers of the Pt(111) and Pt(100) slab were
allowed to relax. The Brillouin-zone integration was performed
X. Wei, J. Li, X. Zhang, G. Wang, S. X. Mao, Z. Zhang, Chem. Commun.
(
2
015, 51, 350–353; b) Z.-F. Gao, H. Chen, S.-T. Qi, C.-H. Yi, B.-L. Yang,
Acta Phys. -Chim. Sin. 2013, 29, 1900–1906.
[9] Y.-W. Lee, S.-B. Han, D.-Y. Kim, K.-W. Park, Chem. Commun. 2011, 47,
6296–6298.
10] Z. Yang, J. Li, X. Yang, X. Xie, Y. Wu, J. Mol. Catal. A 2005, 241, 15–22.
[
ChemCatChem 2018, 10, 1–10
www.chemcatchem.org
8
© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
��
These are not the final page numbers!

Full Papers
[
11] J. Shen, W. Shan, Y. Zhang, J. Du, H. Xu, K. Fan, W. Shen, Y. Tang, J.
[19] a) A. Miyazaki, I. Balint, Y. Nakano, J. Nanopart. Res. 2003, 5, 69–80;
b) J. W. Yoo, D. J. Hathcock, M. A. El-Sayed, J. Catal. 2003, 214, 1–7; c) R.
Narayanan, M. A. El-Sayed, J. Phys. Chem. B 2005, 109, 12663–12676;
d) J. C. Serrano-Ruiz, A. López-Cudero, J. Solla-Gullón, A. Sepúlveda-
Escribano, A. Aldaz, F. Rodríguez-Reinoso, J. Catal. 2008, 253, 159–166.
[20] W. Stöber, A. Fink, E. Bohn, J. Colloid Interface Sci. 1968, 26, 62–69.
[21] G. J. Butterworth, Fusion Technol. 1992, 21, 1994–2000.
[22] G. Kresse, J. Furthmüller, Phys. Rev. B 1996, 54, 11169–11186.
[23] P. E. Blöchl, Phys. Rev. B 1994, 50, 17953–17979.
[24] J. P. Perdew, K. Burke, M. Ernzerhof, Phys. Rev. Lett. 1996, 77, 3865–3868.
[25] M. P. Teter, M. C. Payne, D. C. Allan, Phys. Rev. B 1989, 40, 12255–12263.
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
2
3
4
5
6
7
Catal. 2006, 237, 94–101.
[12] D. Santhanaraj, C. Suresh, P. Vijayan, N. Venkatathri, K. Shanthi, React.
Kinet. Mech. Catal. 2010, 99, 439–446.
[13] G. Zhao, F. Yang, Z. Chen, Q. Liu, Y. Ji, Y. Zhang, Z. Niu, J. Mao, X. Bao, P.
Hu, Y. Li, Nat. Commun. 2017, 8, 14039–14046.
[14] W. Hong, X. Yan, R. Li, J. Fan, Chin. J. Catal. 2017, 38, 545–553.
[15] W. Yi, W. Yuan, Y. Meng, S. Zou, Y. Zhou, W. Hong, J. Che, M. Hao, B. Ye,
L. Xiao, Y. Wang, H. Kobayashi, J. Fan, ACS Appl. Mater. Interfaces 2017,
9, 31853–31860.
[16] H. Song, R. M. Rioux, J. D. Hoefelmeyer, R. Komor, K. Niesz, M. Grass, P.
Yang, G. A. Somorjai, J. Am. Chem. Soc. 2006, 128, 3027–3037.
[
17] a) R. Dittmeyer, G. Emig, in Handbook of Heterogeneous Catalysis (Eds.:
G. Ertl, H. Knözinger, F. Schüth, J. Weitkamp), Wiley-VCH, Weinheim,
2008, pp. 1727–1784; b) Y. Moro-Oka, Y. Morikawa, A. Ozaki, J. Catal.
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
1967, 7, 23–32.
[
18] a) H. Lee, S. E. Habas, S. Kweskin, D. Butcher, G. A. Somorjai, P. Yang,
Angew. Chem. 2006, 118, 7988–7992; Angew. Chem. Int. Ed. 2006, 45,
7824–7828; b) T. Herricks, J. Chen, Y. Xia, Nano Lett. 2004, 4, 2367–2371.
Manuscript received: August 7, 2018
Revised manuscript received: October 2, 2018
Version of record online: ■■■, ■■■■
ChemCatChem 2018, 10, 1–10
www.chemcatchem.org
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© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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FULL PAPERS
Pt does it again! The morphology of
Pt nanoparticles was successfully
regulated by calcinating Pt/SiO2
catalysts in different atmospheres
and achieved a 78.1% cyclohexa-
none yield at 170°C in oxidative de-
W. Hong, Z.-Q. Wang, Dr. S. Zou*, Y.
Zhou, Dr. L. Lu, Q. Zhou, Prof. X.-Q.
Gong*, Prof. J. Fan*
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Calcination Atmosphere Regulated
Morphology and Catalytic Perform-
hydrogenation of KA-oil.
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ance of Pt/SiO in Gas-phase
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Oxidative Dehydrogenation of KA-
oil