Significance of surface oxygen-containing groups and heteroatom P species in switching the selectivity of Pt/C catalyst in hydrogenation of 3-nitrostyrene

Article abstract of DOI:10.1016/j.jcat.2018.05.025

The selectivity of 3-nitrostyrene (NS) hydrogenation over 0.5 wt-% Pt catalysts supported on carbon materials can be switched simply by changing reduction temperature. When the reduction temperature was 150 °C, 1-ethyl-3-nitrobenzene (ENB) was mainly produced in a selectivity of 93% at a conversion of 95% (at 100 °C). When the reduction was conducted at a higher temperature of 450 °C, in contrast, the main product was switched to 3-aminostyrene (AS) in a selectivity of 96% at a conversion of 91%. That is, the Pt/C catalysts reduced at low and high temperatures could preferentially catalyze the hydrogenation of vinyl and nitro groups of NS, respectively. This switching of the product selectivity may be ascribed to actions of surface oxygen-containing functional groups and surface hetero P species. The quantity and nature of these surface species were examined in detail by a few different methods. For the low-temperature reduced catalyst, surface acidic groups present close to Pt nanoparticles (～2 nm) would interact with the nitro group of a NS molecule and make its vinyl group more likely to interact with the surface active metal species of Pt nanoparticles; this facilitates the hydrogenation of the latter and produces ENB selectively. For the high-temperature reduced catalyst, however, P species would interact with Pt and form Pt-PO_x complex, on which a NS molecule is likely to be adsorbed with its nitro group, facilitating the selective production of AS via its hydrogenation. It is demonstrated that surface functional groups and surface hetero atoms (like P), in addition to main active metal species (like Pt), should have direct actions in the catalysis for such a catalyst that exposes a larger quantity of surface functional groups and/or hetero atoms compared to the number of supported metal nanoparticles.

Full text of DOI:10.1016/j.jcat.2018.05.025

Journal of Catalysis 364 (2018) 297–307
Contents lists available at ScienceDirect
Journal of Catalysis
journal homepage: www.elsevier.com/locate/jcat
Significance of surface oxygen-containing groups and heteroatom
P species in switching the selectivity of Pt/C catalyst in hydrogenation
of 3-nitrostyrene
c
a
a
a
a
Qifan Wu a,b, Bin Zhang a, Chao Zhang a, , Xiangchun Meng , Xinluona Su , Shan Jiang , Ruhui Shi , Yan Li ,
⇑
Weiwei Lin a, Masahiko Arai a, Haiyang Cheng a, Fengyu Zhao a,
⇑
a State Key Laboratory of Electroanalytical Chemistry, Laboratory of Green Chemistry and Process, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences,
Changchun 130022, PR China
b University of Science and Technology of China, Hefei, Anhui 230026, PR China
c Changchun University of Technology, Changchun 130012, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
The selectivity of 3-nitrostyrene (NS) hydrogenation over 0.5 wt-% Pt catalysts supported on carbon
materials can be switched simply by changing reduction temperature. When the reduction temperature
was 150 °C, 1-ethyl-3-nitrobenzene (ENB) was mainly produced in a selectivity of 93% at a conversion of
95% (at 100 °C). When the reduction was conducted at a higher temperature of 450 °C, in contrast, the
main product was switched to 3-aminostyrene (AS) in a selectivity of 96% at a conversion of 91%. That
is, the Pt/C catalysts reduced at low and high temperatures could preferentially catalyze the hydrogena-
tion of vinyl and nitro groups of NS, respectively. This switching of the product selectivity may be
ascribed to actions of surface oxygen-containing functional groups and surface hetero P species. The
quantity and nature of these surface species were examined in detail by a few different methods. For
the low-temperature reduced catalyst, surface acidic groups present close to Pt nanoparticles (ꢀ2 nm)
would interact with the nitro group of a NS molecule and make its vinyl group more likely to interact
with the surface active metal species of Pt nanoparticles; this facilitates the hydrogenation of the latter
and produces ENB selectively. For the high-temperature reduced catalyst, however, P species would
interact with Pt and form Pt-POx complex, on which a NS molecule is likely to be adsorbed with its nitro
group, facilitating the selective production of AS via its hydrogenation. It is demonstrated that surface
functional groups and surface hetero atoms (like P), in addition to main active metal species (like Pt),
should have direct actions in the catalysis for such a catalyst that exposes a larger quantity of surface
functional groups and/or hetero atoms compared to the number of supported metal nanoparticles.
Ó 2018 Elsevier Inc. All rights reserved.
Received 4 January 2018
Revised 23 May 2018
Accepted 28 May 2018
Keywords:
Platinum
Carbon
Hydrogenation
3-Nitrostyrene
Selectivity
Support effects
1. Introduction
the surface structure, increase the hydrophilicity, enhance p-
binding ability, and improve electron transport [6,7].
Phosphorous-doped carbon materials have different geometrical
structure compared to parent materials and the electronic state
of neighboring C atoms can be altered by creating a negative
charge [8,9]. For carbon-supported metal catalysts, the SOFGs
and surface heteroatom dopants of carbon materials could influ-
ence the dispersion of metal nanoparticles thereon [10–14] and
the adsorption of organic substrates [15–19] and metal precursors
[20,21]. To design and fabricate carbon-supported metal catalysts
and understand reaction mechanisms on their surface, it is desir-
able to clarify the effects of SOFGs and heteroatom dopants on
their catalytic actions in detail. However, such a systematic study
still remains unexplored issues although the interactions between
Carbon materials, as versatile catalyst supports, have attracted
extensive attention [1,2], owing to their low cost, excellent chem-
ical stability, tunable electronic structure, optimum porosity, and
abundant surface oxygen functional groups (SOFGs). The SOFGs
(such as carboxyl, carbonyl, lactone, and phenolic hydroxyl) have
significant impacts on the properties such as polarity, hydropho-
bicity, acidity, and electronic state. The properties of carbon mate-
rials can be modified by heteroatom doping (N, P, S, etc.) [3–5]. The
doping of electron-rich nitrogen to carbon materials may change
⇑
Corresponding authors.
E-mail addresses: czhang@ciac.ac.cn (C. Zhang), zhaofy@ciac.ac.cn (F. Zhao).
https://doi.org/10.1016/j.jcat.2018.05.025
0021-9517/Ó 2018 Elsevier Inc. All rights reserved.

298
Q. Wu et al. / Journal of Catalysis 364 (2018) 297–307
metal nanoparticles and carbon surface have been investigated in
the past two decades [22,23].
activated coconut carbon (Fujian Xin Sen, C ꢁ 99.0%, ash ꢃ 0.5%,
bulk density 0.32–0.4 kg/L), which are abbreviated as ACH and
AC, respectively, in the following. Phytic acid solution (Aladdin,
70%) was used as phosphine resource.
Although selective hydrogenation has widely been used in the
fine chemical industry, such as in the production of flavors, fra-
grances, pharmaceuticals, pigments, dyes, and agrochemicals
[24–27], the preparation of more active catalysts and the under-
standing of reaction mechanisms are still important topics in the
field of catalytic chemistry and chemical engineering [28]. Selec-
tive hydrogenation of 3-nitrostyrene (NS), having two functional
groups of nitro and vinyl in a molecule, is a useful model reaction
for the investigation of the catalysis of supported metal catalysts. It
is reported that metal-support cooperation [29,30], alloy [31–33],
intermetallic compounds [32,34], metal-ligand (modified with
organics) [2,35,36], and single-atom catalysis [37] are often used
as effective strategies for designing the catalysts that are selective
to the hydrogenation of nitro group of NS. It is indicated that the
2.2. Catalyst preparation
Onto those ACH and AC carbon supports, 0.5 wt-% Pt was loaded
by incipient wetness method. 13.3 mg H2PtCl6ꢂ6H2O was dissolved
in 10 mL ethanol and then 1.0 g carbon support was added to form
a slurry mixture. The slurry was dried at 80 °C in a water bath
while stirring and then kept at 80 °C in an oven overnight. Prior
to usage, the Pt-loaded samples were reduced under pure H2 flow
at 150 °C for 2 h. The catalysts so reduced at the final temperature,
T (150, 385, 450 and 500 °C), are referred to as Pt/ACH-T and Pt/AC-
T in the following.
chemoselectivity
of
NS
hydrogenation
(3-aminostyrene,
To modify the surface properties of carbon supports, the follow-
ing treatments were made for ACH and AC samples. The samples
were treated with a 5 mol/L HNO3 solution at 30 °C for 20 h, then
washed with H2O and ethanol independently, and dried at 80 °C
overnight, which were referred to as ACH-HNO3 and AC-HNO3. It
was also treated with pure water at 30 °C for 20 h, washed with
H2O until the filter liquor became neutral, and dried at 50 °C over-
night, which was referred to as ACH-H2O. The AC also was treated
with a phytic acid solution to dope heteroatom P in 1.7 wt-%, in
which carbon support was impregnated with phytic acid with a
weight ratio of 1000/517 in 10 mL ethanol solution at 30 °C for
24 h and then dried at 80 °C overnight, followed by calcination in
nitrogen at increasing temperatures up to 550 °C at 2 °C/min and
then at 550 °C for 2 h.
3-ethylnitrobenzene) can be switched over a Pt-quinoline@IL
(ionic liquid)/CNT (carbon nanotube) catalyst by adding acid or
basic organics into the reaction system [38]. In Rh/HAP (hydroxya-
patite) catalytic system, the chemoselectivity can be varied by
changing the source of hydrogen from H2NNH2 (product was
3-aminostyrene) to H2 (product was1-ethyl-3-nitrobenzene) [39].
Those results indicate that the product selectivity can be controlled
by reaction conditions for the same supported metal catalysts but
those catalytic systems need complicated catalyst synthesis proce-
dures and unfavorable additives. The present authors expected
that the product selectivity of conventional carbon-supported
metal catalysts could be modified by changing the amount and
nature of surface functional groups of the supports, which would
contribute directly or indirectly to the catalysis on their surface.
During the course of our investigation on the catalysis of ordi-
nary carbon-supported noble metal catalysts, we have examined
the activity of 0.5 wt-% Pt samples on a carbon material including
several different SOFGs and hetero P atoms in the selective hydro-
genation of NS in the present work. It is interesting to note that the
product selectivity can be dramatically switched by reduction tem-
perature; the low (150 °C) temperature reduced Pt catalyst selec-
tively produces 1-ethyl-3-nitrobenzene (ENB) in a selectivity of
93% at a conversion of 95% while the high (450 °C) temperature
reduced one 3-aminostyrene (AS) via hydrogenation of nitro group
in a selectivity of 96% at a conversion 91%. Several different carbon-
supported Pt samples were prepared using two parent carbon
materials and those prepared via their surface modification in dif-
ferent ways and these were tested in NS hydrogenation. Various
methods were used to characterize the surface of supported Pt
nanoparticles and carbon supports and significant factors deter-
mining the product selectivity were examined and discussed. It
should be noted that cooperation of Pt nanoparticles with SOFGs
(in particular acidic groups) and interactions between Pt and het-
ero P species are significant for the product selectivity of the
low-temperature and high-temperature reduced Pt/C catalysts,
respectively. The results obtained will give new insights into the
design, preparation, and catalysis of carbon-supported metal
catalysts.
2.3. Catalyst characterization
The carbon supports and 0.5 wt-% Pt loaded catalysts were
characterized by the following methods. Nitrogen adsorption-
desorption experiments (BET) were performed with
a
Micromeritics ASAP 2020 surface area and porosity analyzer.
X-ray photoelectron spectroscopy (XPS) measurements were car-
ried on VG Microtech 3000 Multilab without sputtering. Transmis-
sion electron microscopy (TEM) images were collected on a JEOL
JEM-2010 instrument operated at an accelerating voltage of 200
kV. Temperature programmed reduction (TPR) profiles were mea-
sured on Micromeritics AutoChem II 2920. For TPR, a sample (50
mg) was treated with argon at 100 °C for 1 h to remove H2O and
cooled to 50 °C. Then, the sample was heated at 5 °C/min to 700
°C in a stream of H2/Ar mixture at a flow rate of 50 mL/min. The
amount of H2 consumed was measured by a gas chromatograph
with thermal conductivity detector. The size and metal dispersion
of Pt nanoparticles were examined by CO pulse adsorption at 50 °C
with a pulse of CO/He (10%) on Micromeritics AutoChem II 2920. A
sample weight was 50 mg and the volume of pulse was 50 mL/min.
The nature and quantity of SOFGs were examined by temperature
programmed decomposition (TPD) on QIC-20, Hiden, UK, with a
mass spectrometer (TPD-MS). A sample (200 mg) was heated in
Ar stream at 30 mL/min and at 5 °C/min from 100 to 1000 °C.
The different SOFGs species were identified by analysis of TPD pro-
files obtained using the peak assignment and deconvolution proce-
dures described by Figueiredo et al [40,41]. The amounts of CO and
CO2 released from 200 mg carbon supports were calibrated by
those of CO and CO2 released from a reference of 200 mg calcium
oxalate. According to the chemical equation (CaC2O4 ? CaO + C
O2 + CO), CO2 and CO were released and the corresponding MS sig-
nals were obtained. These calibration data were used to measure
the amounts of CO and CO2 released from carbon supports. The
contents of P, S, and N contained in the carbon supports were mea-
sured by Inductively Coupled Plasma (ICP) on ThermoScientific
2. Experimental
2.1. Materials
Commercially available reagents, 3-nitrostyrene (Acros; ꢁ97%),
H2PtCl6ꢂ6H2O (Shanghai Jiu Ling; ꢁ99.9%), toluene, ethanol, and
nitric acid (Beijing chemicals; ꢁ 99.9%) were used as received.
Two different raw carbon materials were used, activated charcoal
(Sigma-Aldrich, untreated powder, 100–400 mesh, C3345) and

Q. Wu et al. / Journal of Catalysis 364 (2018) 297–307
299
XseriesII. The adsorption of 3-nitrostyrene was examined by in situ
diffuse reflectance infrared Fourier transform spectroscopy (DRIFT)
on Thermo Scientific Nicolet 6700 Fourier transform infrared spec-
troscopy. A catalyst sample was reduced at 150 or 450 °C for 30
min in FTIR cell with 10% H2/Ar mixture (30 mL/min) and then
cooled to 30 °C. The cell was purged with Ar (30 mL/min) for 30
min and the background spectrum was recorded. After the addition
of 94% in 480 min (entry 2). Further increase in the reduction tem-
perature further increased the selectivity to AS (entries 3 and 4),
which was 96% for the catalyst reduced at 450 °C at a conversion
of 91% in 1440 min (entry 3). Those results demonstrate that the
catalyst reduced at a low temperature of 150 °C selectively cat-
alyzes the hydrogenation of vinyl group of NS but not of vinyl
group of AS and nitro group of NS and ENB; however, those
reduced at higher temperatures selectively hydrogenate nitro
group of NS but not nitro group of ENB and vinyl group of NS
and AS. In addition, site-time-yield, STY, of the main product
decreases with the increasing reduction temperature in a range
of 150–500 °C to such a large extent as two or three orders of mag-
nitude, as shown in Table 1.
of 40
lL substrate (0.5 M in toluene) to the sample, the tempera-
ture of the cell was raised to 150 °C slowly while passing Ar flow
(30 mL/min). The spectrum was recorded at 150 °C every 30 min
until all the physically adsorbed species were removed.
2.4. Hydrogenation
The size of supported Pt nanoparticles was examined by both
TEM and CO pulse adsorption methods (Fig. 1 and Table 1).
Although the product selectivity is significantly different between
the catalyst reduced at 150 °C (entry 1) and those at 385 and
450 °C (entries 2 and 3), the sizes of Pt nanoparticles are compara-
ble among these catalysts. A larger Pt particle size was observed for
the catalyst reduced at a higher temperature of 500 °C (entry 4) but
the product selectivity was the same as observed with the ones
reduced at 385 and 450 °C. Hence, the size of supported Pt
nanoparticles is not a factor responsible for the selectivity switch-
ing by the reduction temperature as observed.
The catalytic performance of Pt catalysts on raw and surface-
modified carbon supports were tested for the selective hydrogena-
tion of 3-nitrostyrene using a 50 mL stainless steel autoclave with
an inner Teflon coating. For a typical catalytic reaction, 0.5 mmol
3-nitrostyrene and 10–40 mg catalyst were mixed in 5 mL toluene.
The reactor was purged with 2 MPa H2 three times and it was
sealed. The reaction was conducted at 4 MPa H2 at 100 °C. The prod-
ucts were analyzed by gas chromatography (Shimadzu, 2010)
equipped with a capillary column (Restek-5 30 m ꢄ 0.25 mm ꢄ
0.25 lm) and a flame ionization detector (FID). Conversion was
determined by dividing the amount of NS consumed by the initial
amount of NS; product selectivity was calculated by dividing the
amount of a certain product by the amount of NS consumed.
Site-time-yield was calculated by dividing the amount a certain
product by the amount of exposed Pt atoms and reaction time.
3.2. Influence of SOFGs in NS hydrogenation
Next, the influence of SOFGs on the catalytic performance was
examined for Pt/ACH and Pt/AC samples, in which the carbon sup-
ports were treated with an acid of HNO3. Table 2 shows the results
of NS hydrogenation with Pt catalysts on HNO3-treated and
untreated supports reduced at 150 °C, which were collected at sim-
ilar high conversion levels. For the Pt/ACH samples, the acid treat-
ment of the support did not change the high selectivity to ENB but
decreased the rate of hydrogenation (entries 1 and 2). The activity
of Pt on untreated AC was comparable to that of Pt on untreated
ACH but the selectivity to ENB was smaller and that to EA was lar-
ger for the former catalyst compared to the latter one (entries 1
and 3). It is interesting to note that Pt/ACH catalyst catalyzes the
hydrogenation of vinyl group of NS (but not nitro group of ENB)
while Pt/AC one catalyzes the hydrogenation of both nitro group
and vinyl group. When AC was treated by HNO3, the rate of hydro-
genation was decreased but the ENB selectivity was enhanced
(entry 4), similar to the results with Pt/ACH samples.
3. Resulsts and discussion
The reaction pathway for the hydrogenation of 3-nitrostyrene
(NS) is shown in Scheme 1. Under the reaction conditions used,
1-ethyl-3-nitrobenzene (ENB), 3-aminostyrene (AS), and 3-
ethylaniline (EA) were formed with trace amounts of other minor
products of 3-hydroxylamine styrene, 3-azostyrene, 3-
azoxystyrene, and 3-vinylnitrosobenzene. The product selectivity
as well as the rate of hydrogenation was observed to be signifi-
cantly influenced by reduction temperature and the presence of
SOFGs and the surface heteroatom P species.
3.1. Influence of reduction temperature in NS hydrogenation
The TEM images of these catalysts were given in Fig. S1, and the
surface properties of supported Pt and carbon support materials
were examined by XPS, TPD, and TPR. Fig. 2 (and Fig. S2) gives Pt
4f XPS spectra for Pt/ACH and Pt/AC samples. Each spectrum was
fitted by four separated components with peaks at 71.8, 75.2,
73.3, and 76.5 eV; the former two were assignable to Pt0 species
(4f7/2, 4f5/2) while the latter two to Ptd+ species [22]. The ratio of
Ptd+ against Pt0 was calculated by dividing the total Ptd+ area by
the total Pt0 area. The results calculated are also given in Table 2,
indicating that the Ptd+/Pt0 ratio is larger for Pt on HNO3-treated
carbon than on untreated one for either Pt/ACH or Pt/AC samples
although the sizes of Pt nanoparticles are comparable. That is,
the surface of supported Pt nanoparticles becomes likely to expose
more Ptd+ species by the HNO3 treatment of carbon supports. This
suggests the existence of some metal-support interactions affect-
ing the chemical state of exposed Pt species.
Initially, the influence of reduction temperature on the catalytic
performance was examined for Pt/ACH samples, which were
reduced at temperatures of 150–500 °C. The results collected at
conversion levels of 86–95% are given in Table 1. The catalyst
reduced at 150 °C gave a conversion of 95% in 5 min and produced
ENB in a high selectivity of 93% (entry 1). When the reduction tem-
perature was raised to 385 °C, in contrast, the main product was
dramatically switched to AS in a selectivity of 81% at a conversion
NO2
H2
H2
ENB
(
)
NH2
NO2
The type and amount of SOFGs on the surface of Pt-loaded and
unloaded samples were examined by TPD-MS [42–44]. The TPD
pattern of either CO2 or CO desorption was observed in a wide
range of temperature of 100–1000 °C and it was separated to four
different desorption components (Figs. S3 and S4), which were car-
boxyl (peaks 1 and 2), anhydride (peak 3), and lactone (peak 4)
EA
(
)
NS
H2
H2
(
)
NH2
AS
(
)
Scheme 1. Reaction pathways for the hydrogenation of 3-nitrostyrene.

300
Q. Wu et al. / Journal of Catalysis 364 (2018) 297–307
Table 1
Catalytic performances of Pt/ACH-T catalysts in 3-nitrostyrene hydrogenation.
e
Entry
Catalyst
Time (min)
Conversion (%)
Selectivity (%)
Particle size (nm)b
Particle size (nm)c
Pt dispersion (%)d
STY (hꢅ1
)
AS
ENB
EA
Othersa
1
2
3
4
Pt/ACH-150
Pt/ACH-385
Pt/ACH-450
Pt/ACH-500
5.0
480
1440
1440
95
94
91
85
0
93
2
0
4
15
1
3
2
3
3
2.1
2.0
2.5
8.0
2.6
2.8
3.2
7.5
43
34
30
16
1.2 * 104 (ENB)
1.4 * 102 (AS)
60 (AS)
81
96
93
1
3
1.0 * 102 (AS)
Reaction conditions: 0.5 mmol 3-nitrostyrene, 40 mg catalyst (Pt loading was 0.5 wt-% for all catalysts), 4 MPa H2, 100 °C.
a
Others are traces of 3-hydroxylamine styrene, 3-azostyrene, 3-azoxystyrene and 3-vinylnitrosobenzene.
Determined by TEM images.
Determined by CO pulse adsorption.
STY = moles of EBN or AS produced per mole of exposed Pt per 1 h.
b
c,d
e
shows that the surface of AC exposes a smaller amount of SOFGs
than ACH (entries 1 and 7). Furthermore, note that there are a
number of acidic groups on the surface of carbon supports in the
present Pt/C catalysts; these groups may interact with a polar
group (nitro of NS in the present case) and affect its reactivity.
Finally, interactions between Pt species and carbon supports
were examined by TPR. Fig. 3 gives the results of TPR with Pt-
loaded and unloaded carbon samples. For Pt/ACH sample, four
peaks were detected at 150, 298, 430 and 550 °C, in which the peak
at 150 °C was assignable to the reduction to Pt0. The second peak at
298 °C was ascribed to reduction of Pt species having strong inter-
actions with the surface acidic groups and the one at 430 °C
resulted from the reduction of Pt-POx composites [43,44]. The
removal of SOFGs from support became more likely to take place
at 550 °C as indicated in Fig. 3b for carbon supports alone. This
interferes the measurement of H2 consumption on TPR and so
our discussion was limited to the data at lower temperatures. For
Pt on HNO3-treated ACH, the peak related to Pt species having
strong interactions with the surface acidic groups shifted to around
350 °C. A similar peak was also observed in Pt on HNO3-treated AC.
In addition, the HNO3 treatment caused the peaks related to Pt0 to
shift to 210 °C on HNO3-treated ACH and 190 °C on HNO3-treated
AC, indicating that only partial reduction of Pt4+ took place at
150 °C and thus resulted in a lower Pt0 content. However, the Pt0
peak on AC was at 140 °C and more Pt0 species were formed at a
reduction temperature of 150 °C. That is, the amount of catalyti-
cally active Pt0 species is smaller for Pt on HNO3-treated ACH than
Pt on untreated one, which is responsible for the smaller rate of
hydrogenation observed with the former catalyst (Table 2 entries
1 and 2). This should also be the case for Pt on AC supports (Table 2
entries 3 and 4) but the difference between the two Pt catalysts on
HNO3-treated and untreated AC supports is less significant because
of their inherent smaller amounts of acidic functional groups.
From those reaction and characterization results, it is assumed
that the rate of NS hydrogenation of low-temperature (150 °C)
reduced Pt catalysts changes with the type and amount of SOFGs
of carbon supports, which influence the reduction behavior of
Fig. 1. TEM images and particle size distribution of Pt/ACH-150 (a), Pt/ACH-385 (b),
Pt/ACH-450 (c), and Pt/ACH-500 (d).
from the CO2 desorption and anhydride (peak 3), phenol (peak 5),
ether (peak 6), and carboxyl (peak 7) from CO desorption [13,40–
42]. The amounts of those different types of SOFGs determined
are given in Table 3. The total amount of SOFGs was little changed
by the loading of 0.5 wt-% Pt and the following reduction at 150 °C
(entries 1, 4; entries 7, 8). The treatment with HNO3 significantly
increased the amount of SOFGs including carboxyl and anhydride
groups, as expected (entries 1, 2). It was previously suggested that
such acidic groups on carbon supports were sites on which metal
nanoparticles were anchored and immobilized [12,13]. Table 3 also
Table 2
Catalytic performances of Pt supported on different carbon materials reduced at 150 °C in 3-nitrostyrene hydrogenation.
c
Entry
Catalyst
Time (min)
Conversion (%)
Selectivity (%)
Particle size (nm)
Pt dispersion (%)a
Ptd+/Pt0b
STYENB (hꢅ1
)
AS
ENB
EA
Others
1
2
3
4
Pt/ACH-150
Pt/(ACH-HNO3)-150
Pt/AC-150
5
180
5
95
97
94
85
0
1
5
2
93
97
53
95
4
0
35
2
3
2
7
1
2.6
2.6
1.7
2.3
43
43
59
51
0.8
2.6
0.5
2.3
1.2 * 104
3.8 * 102
9.9 * 103
7.7 * 102
Pt/(AC-HNO3)-150
240
Reaction conditions: 0.5 mmol 3-nitrostyrene, 40 mg catalysts (20 mg for entry 3, 10 mg for entry 4, Pt loading was 0.5 wt-% for all catalysts), 4 MPa H2, 100 °C.
a
Determined by CO pulse adsorption.
Determined by XPS.
STY = moles of EBN produced per mole of exposed Pt per 1 h.
b
c

Q. Wu et al. / Journal of Catalysis 364 (2018) 297–307
301
Fig. 2. Pt 4f XPS spectra of Pt/ACH-150, Pt/(ACH-HNO3)-150, Pt/AC-150, and Pt/(AC-HNO3)-150 (a–d).
Table 3
The amounts of SOFGs on different carbon supports and Pt-loaded catalysts.
Entry
Samples
Quantity (number of groups/nm2) of SOFGsa
Total quantity of
SOFGs
Area, m2/gb
Carboxyl peak
1 and 2
Anhydride peak
3
Lactone peak
4
Phenol peak
5
Ether peak
6
Carbonyl peak
7
1.
2.
3
4
5
6
7
8
9
ACH
ACH-HNO3
ACH-450
Pt/ACH-150
Pt/(ACH-HNO3)-150
Pt/ACH-450
AC
Pt/AC-150
Pt/AC-450
0.14
0.53
0.02
0.08
0.51
0.01
0.04
0.04
0.01
0.09
0.18
0.03
0.05
0.18
0.02
0.02
0.02
0.01
0.01
0.13
0.01
0.02
0.13
0.01
0.02
0.02
0.01
0.16
0.42
0.09
0.17
0.68
0.06
0.08
0.08
0.08
0.17
0.27
0.12
0.16
0.44
0.08
0.09
0.08
0.11
0.10
0.21
0.07
0.07
0.24
0.02
0.03
0.05
0.07
0.67
1.74
0.34
0.55
2.18
0.20
0.28
0.29
0.29
1262
744
1262
1262
744
1262
1851
1851
1851
a
Determined by deconvolution of the CO2 TPD-MS and CO TPD-MS spectra.
Determined by BET.
b
Fig. 3. TPR profiles of Pt/ACH, Pt/AC, Pt/(ACH-HNO3), and Pt/(AC-HNO3) catalysts unreduced (a) and the corresponding metal-free supports (b).
supported Pt precursors, changing the amount of exposed Pt0 spe-
cies although the size of Pt nanoparticles is not influenced.
nal content of P in AC was very small (0.034 wt-%, Tables S1 and 4).
Table 4 shows the results of selective NS hydrogenation obtained
with Pt catalysts on those supports. Either the product selectivity
or the hydrogenation rate was similar between Pt/AC-150 and
Pt/(AC-P)-150 (entries 1 and 2) although the P content was signif-
icantly different. Compared to Pt/AC-450, Pt/(AC-P)-450 showed a
smaller rate of NS hydrogenation and a larger selectivity to AS
3.3. Influence of surface hetero P species in NS hydrogenation
Furthermore, the influence of hetero P species on the catalytic
performance was examined for Pt/AC samples, in which the origi-

302
Q. Wu et al. / Journal of Catalysis 364 (2018) 297–307
Table 4
Catalytic performances of 0.5 wt-% Pt supported on different carbon materials reduced at 450 °C and 150 °C.
Entry Catalyst Time (min) Conversion (%) Selectivity (%)
Ptd+/Pt0a P, wt.-%b Particle size (nm)
AS ENB EA Others
53 35
d
Pt dispersion (%)d STY (hꢅ1
)
1
Pt/AC-150
5
94
94
99
99
91
91
5
7
0.5
0.5
0.5
0.9
2.5
1.4
0.034
1.700
0.034
1.700
1.680
0.716
1.7
2.6
2.0
3.4
3.2
2.0
59
43
54
34
30
55
9.9 * 103 (ENB)
9.5 * 103 (ENB)
3.1 * 103 (AS)
2.0 * 102 (AS)
60 (AS)
2c
3
Pt/(AC-P)-150
Pt/AC-450
5
60
11 37 41 11
35
83
96
0
0
0
56
9
9
8
2
2
4c
5
Pt/(AC-P)-450
Pt/ACH-450
360
1440
2
6
Pt/(ACH-H2O)-450 1080
55 10
33
25 (AS)
Reaction conditions: 0.5 mmol 3-nitrostyrene, 40 mg catalysts (20 mg for entries 1 and 2), 4 MPa H2, 100 °C.
a
Determined by XPS.
Determined by ICP.
AC-P carbon support was synthesized by doping the P heteroatom to AC.
Determined by CO pulse adsorption.
b
c
d
(entries
3
and 4). Therefore, the difference in the catalysis
ified by 31P NMR (Fig. S6). Since P (organophosphorus com-
pounds) was both donor and acceptor, the p -d bond
(selectivity and rate) between Pt/AC-450 and the other catalysts
of Pt/(AC-P)-450, Pt/AC-450, and Pt/ACH-450 should be related to
the marked difference in the P species. Namely, the catalyst includ-
ing P in a larger content is more selective to the formation of AS but
less active. This trend was also observed with Pt/ACH samples
(entries 5 and 6).
r
p
p p
could be formed between phosphorus and Pt [48,49]. A similar
difference in the BE value of P 2p was also found between
Pt/(AC-P) samples reduced at 150 and 450 °C. Hence, the influ-
ence of surface P heteroatom is significant for Pt/C catalysts
reduced at a high temperature of 450 °C.
The above-mentioned results suggest the presence of interac-
tions between Pt and P species at a high reduction temperature
of 450 °C. The possibility of Pt-P interactions was examined by
XPS. The XPS results obtained are given in Figs. 4 and 5. Table 4
also shows the results of Ptd+/Pt0 ratio, which tends to be larger
for Pt on either ACH or AC support containing a larger amount
of P species (entries 1, 3; entries 2, 4). For Pt/AC samples reduced
at a lower temperature of 150 °C, however, the Ptd+/Pt0 ratios
were similar irrespective of the P content (Table 2 entry 3, Table 4
entry 2), suggesting no interactions between Pt and P species. The
P 2p XPS spectra were separated into two components (Fig. 5,
Fig. S5) and their peaks were located at binding energy (BE) val-
ues of 133.7 and 134.5 eV. The latter is assignable to the oxidized
phosphorus, P bound to at least three oxygen atoms while the
former to the P bound to one or two oxygen atoms, more likely
phosphite groups [45–47]. When compared to Pt/ACH reduced
at 150 °C, that reduced at 450 °C had a lower BE value of P 2p,
suggesting the partial reduction of -POx groups and the formation
of Pt-POx composites, in accordance with the TPR results (Fig. 3).
In addition, the chemical changes of P environment were also ver-
Note again that the product selectivity and the rate of NS hydro-
genation for Pt/carbon catalysts reduced at higher temperatures
(>385 °C) depend on the type and amount of hetero P species.
Increasing P content is likely to decrease the rate of NS hydrogena-
tion but increase the selectivity to AS. Interactions between Pt and
P species should appear when the catalyst is reduced at higher
temperatures, at which Pt-POx composite species are formed on
the surface of supported metal particles and influence the rate
and the product selectivity. These aspects will be discussed in more
detail later.
3.4. Influence of water and H2 treatment in NS hydrogenation
The effects of hetero P species and SOFGs were further exam-
ined for Pt/ACH samples, in which these were removed partly by
treatments with water at 30 °C and gaseous H2 at 450 °C.
Table S2 shows the results of NS hydrogenation with those Pt
catalysts. It was found that the P content in ACH support decreased
from 1.68% to 0.71% by the water-treatment and the SOFGs, in par-
ticular carboxyl and anhydride groups, were considerably removed
Fig. 4. Pt 4f XPS spectra of Pt/ACH, Pt/AC, and Pt/(AC-P) reduced at 450 °C (a–c).

Q. Wu et al. / Journal of Catalysis 364 (2018) 297–307
303
Fig. 5. P 2p XPS spectra of Pt/ACH, Pt/(AC-P), and Pt/(ACH-H2O) reduced at 150 °C (a–c) and 450 °C (a0–c0).
by the high-temperature H2 treatment (Table 3 entries 1 and 3). As
above-mentioned, Pt/ACH catalyst reduced at 150 °C was selective
to the hydrogenation of vinyl group of NS, giving ENB in a high
selectivity at a large average reaction rate (Table 1 entry 1). Such
catalytic features remained almost unchanged by the treatment
of ACH support with water when the reduction was made at the
same temperature (Table S2 entries 1 and 3). When Pt on water-
treated ACH was reduced at a higher temperature of 450 °C, the
ENB selectivity and the average reaction rate were similar to those
of Pt on untreated ACH (Table S2 entry 2, Table 1 entry 3). Both
catalysts were selective to the hydrogenation of nitro group of
NS, and the higher P content favors higher AS selectivity. Thus,
the switching of the product selectivity by the reduction tempera-
ture is possible for Pt on parent and water-treated ACH supports
that contain some P species. Although the amount of SOFGs was
significantly different between parent and H2-treated ACH sup-
ports, the low selectivity to ENB (the high selectivity to AS) was
the same for Pt on these supports reduced at 450 °C. It is likely
therefore that SOFGs are a less important factor for determining
the product selectivity for the Pt/ACH catalysts reduced at a high
temperature of 450 °C.
was examined by in-situ FTIR at 150 °C. Fig. 6 gives in-situ FTIR
spectra of NS adsorbed on the two Pt catalysts. The spectra were
initially measured at 150 °C just after the adsorption of NS, includ-
ing physically and chemically adsorbed species. The catalyst
samples were then exposed to an argon stream for 270 min to
remove the physically adsorbed species and again subjected to
FTIR measurements. The absorption bands with peaks at 1530
and 1350 cmꢅ1 are attributed to the anti-symmetric and symmet-
ric stretching vibration modes of ANO2, respectively [50,51]. Those
observed at around 3090 and 3040 cmꢅ1 are assigned to the phys-
ical and chemical adsorption of @CAH (stretching vibration),
respectively [52]. In addition, the three absorption bands at
2870–3000 cmꢅ1 are due to the stretching vibration of @CAH on
benzene ring [53]. After the argon treatment, the absorption bands
related to the chemical adsorption of ANO2 and C@C groups
appeared for one sample of Pt/ACH reduced at 150 °C. For the other
Pt/ACH sample reduced at 450 °C, however, only the absorption
bands due to the chemical adsorption of ANO2 at 1530 and 1350
cm-1 were observed. That is, the adsorption of a NS molecule
should occur with its nitro and vinyl groups on the low-
temperature reduced Pt/ACH catalyst but with its nitro group only
on the high-temperature reduced catalyst.
3.5. Influence of reduction temperature on NS adsorption
3.6. Hydrogenation of nitrobenzene and styrene
As above-mentioned, the product selectivity was significantly
different between Pt/C catalysts reduced at low and high tempera-
tures. Two Pt/ACH samples reduced at 150 and 450 °C were
selected and the adsorption of NS substrate on these catalysts
The catalytic activity of two selected Pt/ACH samples reduced at
150 and 450 °C was further examined for hydrogenation of mono-
functional substrates of nitrobenzene (NB) and styrene (ST) under

304
Q. Wu et al. / Journal of Catalysis 364 (2018) 297–307
Fig. 6. In-situ DRIFT adsorption spectra of 3-nitrostyrene (NS) over Pt/ACH-150 (a and b) and Pt/ACH-450 (c and d). Spectra were collected just after the adsorption of NS at
150 °C (upper results) and the treatment with an Ar stream for 270 min (lower results).
similar reaction conditions.[29] Table S3 summarizes the results
obtained. The catalyst reduced at 150 °C catalyzed the hydrogena-
tion of either NB or ST (entries 1 and 2) but, for a mixture of NB and
ST, ST was more preferentially hydrogenated than NB, in accor-
dance with the selective hydrogenation of vinyl group of NS. The
catalyst reduced at 450 °C was less active than that at 150 °C and
it catalyzed the hydrogenation of NB and ST but at a smaller rate
for ST (entries 4 and 5). For a mixture of NB and ST, the former
was hydrogenated but the latter was difficult, which was similar
to the selective hydrogenation of nitro group of NS to AS. Thus,
the catalytic features of Pt/ACH reduced at the same temperature
are the same for the substrate of NS including both nitro and vinyl
groups and those of NB and ST including either nitro or vinyl group
alone.
3.7. Origin of the selectivity switching
The present results demonstrate that the product selectivity of
NS hydrogenation over 0.5 wt-% Pt/C catalysts can be switched by
the reduction temperature. The low-temperature (150 °C) reduced
catalyst is selective to the hydrogenation of vinyl group of NS, giv-
ing ENB in a high selectivity, at a large average reaction rate

Q. Wu et al. / Journal of Catalysis 364 (2018) 297–307
305
Fig. 7. Schematic illustration of the selective hydrogenation of NS over the Pt/ACH-150 and Pt/ACH-450 catalysts selectively producing ENB and AS, respectively. In the above
the Pt nanoparticles are depicted in a larger size as compared to their experimentally determined size (ꢀ2 nm) for explanation of idea.
(Table 1). In contrast, the high-temperature (> 385 °C) catalyst
selectively catalyzes the hydrogenation of nitro group, resulting
in a high selectivity to AS, but at an even smaller average reaction
rate. The change of the product selectivity with reaction time was
examined for selected catalysts of Pt/ACH that were highly selec-
tive to the formation of either ENB or AS (Figs. S7a and 7b; Tables
S4 and S5). It was shown that the high selectivity remained almost
unchanged with conversion. For comparison, the time dependence
of the product selectivity was also examined for Pt/AC catalysts
that were less selective and the hydrogenation of NS to ENB and
AS simultaneously occurred (Figs. S7c and 7d; Tables S6 and S7).
The product selectivity was observed to change with time; with
Pt/AC-150 the selectivity to ENB and that to EA increased while
that to AS decreased as its further hydrogenation to EA was likely
to occur; with Pt/AC-450, the selectivity to AS and that to EA
increased while that to ENB decreased which was further hydro-
genated to EA. It is important to note that the above-mentioned
catalysts did not show any deactivation during the reaction, as
the reaction goes up smoothly and the conversion increases to near
100% with reaction time under the reaction conditions used. It is
also worth noting that the highly selective catalysts of Pt/ACH con-
tain a large amount of surface acidic groups or hetero P species but
the other less selective catalysts of Pt/AC contain a less amount of
these surface functional species. Those results indicate the signifi-
cant roles of SOFGs and hetero P atoms for determining the pro-
duct selectivity in NS hydrogenation over Pt/C catalysts.
The catalytic performance and surface properties were dis-
cussed in detail for various Pt/C catalysts where the amounts of
SOFGs and hetero P species were varied by different treatments.
The results indicate that the SOFGs and hetero P species are signif-
icant factors for determining the product selectivity for the Pt/C
catalysts reduced at low and high temperatures, respectively, and
the size of supported Pt nanoparticles is insignificant. Note, for
the present Pt/C catalysts containing Pt in 0.5 wt-%, that the num-
ber of SOFGs is even larger by more than three orders of magni-
tudes than that of Pt nanoparticles (assuming hemispherical
shape with a diameter of 2 nm (Tables 1 and 2). This implies that
there are a number of free exposed SOFGs on the surface of support
and some groups should exist close to the Pt nanoparticles. Note
also that a number of hetero P atoms (assuming 1.7 wt-% shown
in Table 4) is larger by more than one order of magnitude than that
of the Pt nanoparticles. It is thus likely that SOFGs, probably acidic
groups, and hetero P atoms contribute to the catalysis in the selec-
tive hydrogenation of NS over Pt/C catalysts. Fig. 7 illustrates
hydrogenation models for the Pt/C catalysts reduced at low and
high temperatures. For the former catalyst, the acidic groups close
to Pt nanoparticles should control the adsorption of an NS mole-
cule; these groups interact with the polar nitro group via hydrogen
bonding [54] and facilitate its adsorption on Pt nanoparticles with
the vinyl group (a similar adsorption mode was reported in cin-
namaldehyde hydrogenation) [55]. As a result, the vinyl group is
more likely to be hydrogenated compared to the nitro group and
ENB is selectively produced. For the high-temperature reduced
catalyst, Pt-POx composites should be formed and partially cover
the surface of Pt nanoparticles. The composites facilitate the selec-
tive adsorption of an NS molecule with its polar nitro group, result-
ing in an enhanced selectivity to AS. The number of exposed Pt0
species is decreased by the formation of Pt-POx composites and
the catalytic features (for example, hydrogen adsorption and acti-
vation ability) of the composites are different from those of Pt0.
Those factors would be responsible for the significant decrease in
the total rate of hydrogenation as observed. That is, supported Pt
nanoparticles cooperate with SFOGs and hetero P atoms in the
low-temperature and high-temperature reduced Pt/C catalysts,
respectively, which causes the switching of the product selectivity
in NS hydrogenation.
In the absence of the contribution of SOFGs and hetero P spe-
cies, an NS molecule can be adsorbed via its vinyl and nitro groups
on the surface of Pt nanoparticles; therefore, ENB and AS are less
selectively produced and their further hydrogenation to EA also
occurs.
4. Conclusions
The present work demonstrates the significance of SOFGs and
heteroatom P species on the catalytic performance of carbon-
supported 0.5 wt-% Pt catalysts in the selective NS hydrogenation.
It is interesting that the product selectivity can be completely
switched by the reduction temperature. A selectivity of 93% to
ENB was obtained over the catalyst reduced at 150 °C while that
of 96% to AS over those at higher temperatures (>385 °C). Namely,
the former catalyst catalyzes the hydrogenation of vinyl group of
NS but, in contrast, the latter the hydrogenation of its nitro group.
For the low-temperature reduced catalyst, the cooperation of Pt
nanoparticles and SOFGs (in particular acidic groups) close to the
nanoparticles facilitates the adsorption of NS with vinyl group on
the surface of Pt nanoparticles assisted by the adsorption/interac-
tion of its polar nitro group on/with SOFGs. The vinyl group is more
likely to be hydrogenated compared to the nitro group, giving ENB
selectively. For the high-temperature reduced catalysts, on the
other hand, Pt-POx composites are formed on the surface of Pt
nanoparticles and promote the selective adsorption/activation of
polar nitro group, resulting in an enhanced selectivity to its hydro-
genation product AS. The surface of supported Pt nanoparticles is
partially covered by Pt-POx composites and the total activity is
decreased significantly. These results provide useful knowledge
for the design and synthesis of heterogeneous metal catalysts with
carbon supports in which the metal loading is small and free

306
Q. Wu et al. / Journal of Catalysis 364 (2018) 297–307
temperature catalyzed by platinum supported on carbon activated with
potassium hydroxide, ChemCatChem 8 (2016) 1699–1707.
[18] M. Almarri, X. Ma, C. Song, Role of surface oxygen-containing functional
groups in liquid-phase adsorption of nitrogen compounds on carbon-based
adsorbents, Energy Fuels 23 (2009) 3940–3947.
surface functional groups such as SOFGs and hetero P atoms are
abundant for selective hydrogenation and other reactions with
organic substrates including two or more functional groups differ-
ent in the nature like vinyl and nitro groups.
[19] M.L. Toebes, Y.H. Zhang, J. Hájek, T. Alexander Nijhuis, J.H. Bitter, A. Jos van
Dillen, D.Y. Murzin, D.C. Koningsberger, K.P. De Jong, Support effects in the
hydrogenation of cinnamaldehyde over carbon nanofiber-supported platinum
catalysts: characterization and catalysis, J. Catal. 226 (2004) 215–225.
[20] V.Z. Radkevich, T.L. Senko, K. Wilson, L.M. Grishenko, A.N. Zaderko, V.Y. Diyuk,
The influence of surface functionalization of activated carbon on palladium
dispersion and catalytic activity in hydrogen oxidation, Appl. Catal. A: Gen.
335 (2008) 241–251.
[21] M.C. Román Martínez, D. Cazorla Amorós, A. Linares Solano, C.S.M. De Lecea, H.
Yamashita, M. Anpo, Metal-support interaction in Pt/C catalysts: influence of
the support surface chemistry and the metal precursor, Carbon 33 (1995) 3–
13.
[22] W. Shi, B.S. Zhang, Y.M. Lin, Q. Wang, Q. Zhang, D.S. Su, Enhanced
chemoselective hydrogenation through tuning the interaction between Pt
nanoparticles and carbon supports: insights from identical location
transmission electron microscopy and X-ray photoelectron spectroscopy,
ACS Catal. 6 (2016) 7844–7854.
Acknowledgements
We gratefully acknowledge the financial support provided by
the
National
Program
on
Key
Research
Project
(2016YFA0602900), National Natural Science Foundation of China
(21473179), the Youth Innovation Promotion Association
(2014203), Chinese Academy of Science, and International Cooper-
ation Project of Jilin Province (20170414012GH), Jilin Provincial
Science and Technology Program of China (20150204050GX).
Appendix A. Supplementary material
[23] B.S. Zhang, L.D. Shao, W. Zhang, X.Y. Sun, X.L. Pan, D.S. Su, Interaction between
palladium nanoparticles and surface-modified carbon nanotubes: role of
surface functionalities, ChemCatChem 6 (2014) 2607–2612.
[24] D. Cantillo, M. Baghbanzadeh, C.O. Kappe, In situ generated iron oxide
nanocrystals as efficient and selective catalysts for the reduction of
Supplementary data associated with this article can be found, in
the online version, at https://doi.org/10.1016/j.jcat.2018.05.025.
nitroarenes using
(2012) 10190–10193.
a continuous flow method, Angew. Chem. Int. Ed. 51
References
[25] S. Zhang, C.R. Chang, Z.Q. Huang, J. Li, Z.M. Wu, Y.Y. Ma, Z.Y. Zhang, Y. Wang, Y.
Q. Qu, High catalytic activity and chemoselectivity of sub-nanometric Pd
clusters on porous nanorods of CeO2 for hydrogenation of nitroarenes, J. Am.
Chem. Soc. 138 (2016) 2629–2637.
[1] S.H. Joo, S.J. Choi, I. Oh, J. Kwak, Z. Liu, O. Terasaki, R. Ryoo, Ordered nanoporous
arrays of carbon supporting high dispersions of platinum nanoparticles, Nature
412 (2001) 169–172.
[26] L. Liu, P. Concepción, A. Corma, Non-noble metal catalysts for hydrogenation: a
facile method for preparing Co nanoparticles covered with thin layered carbon,
J. Catal. 340 (2016) 1–9.
[27] A. Corma, P. Serna, Chemoselective hydrogenation of nitro compounds with
supported gold catalysts, Science 313 (2006) 332–334.
[28] Z. Wei, S. Mao, F. Sun, J. Wang, B. Mei, Y. Chen, H. Li, Y. Wang, The synergic
effects at the molecular level in CoS2 for selective hydrogenation of
nitroarenes, Green Chem. 20 (2018) 671–679.
[2] F.A. Westerhaus, R.V. Jagadeesh, G. Wienhöfer, M.M. Pohl, J. Radnik, A.E.
Surkus, J. Rabeah, K. Junge, H. Junge, M. Nielsen, A. Brückner, M. Beller,
Heterogenized cobalt oxide catalysts for nitroarene reduction by pyrolysis of
molecularly defined complexes, Nature Chem. 5 (2013) 537–543.
[3] Z.Z. Wei, J. Wang, S.J. Mao, D.F. Su, H.Y. Jin, Y.H. Wang, F. Xu, H.R. Li, Y. Wang, In
situ-generated Co0-Co3O4/N-doped carbon nanotubes hybrids as efficient and
chemoselective catalysts for hydrogenation of nitroarenes, ACS Catal. 5 (2015)
4783–4789.
[29] M. Boronat, P. Concepción, A. Corma, S. González, F. Illas, P. Serna, A molecular
mechanism for the chemoselective hydrogenation of substituted
nitroaromatics with nanoparticles of gold on TiO2 catalysts: a cooperative
effect between gold and the support, J. Am. Chem. Soc 129 (2007) 16230–
16237.
[30] A. Corma, P. Serna, P. Concepción, J.J. Calvino, Transforming nonselective into
chemoselective metal catalysts for the hydrogenation of substituted
nitroaromatics, J. Am. Chem. Soc. 130 (2008) 8748–8753.
[31] O. Metin, A. Mendoza Garcia, D. Dalmzrak, M.S. Gultekin, S. Sun, FePd alloy
nanoparticles assembled on reduced graphene oxide as a catalyst for selective
transfer hydrogenation of nitroarenes to anilines using ammonia borane as a
hydrogen source, Catal. Sci. Technol. 6 (2016) 6137–6143.
[32] H.S. Wei, X. Wei, X.F. Yang, G.Z. Yin, A.Q. Wang, X.Y. Liu, Y.Q. Huang, T. Zhang,
Supported Au-Ni nano-alloy catalysts for the chemoselective hydrogenation of
nitroarenes, Chin. J. Catal. 36 (2015) 160–167.
[33] A. Yarulin, C. Berguerand, I. Yuranov, F. Cárdenas Lizana, I. Prokopyeva, L. Kiwi
Minsker, Pt–Zn nanoparticles supported on porous polymeric matrix for
selective 3-nitrostyrene hydrogenation, J. Catal. 321 (2015) 7–12.
[34] S. Furukawa, Y. Yoshida, T. Komatsu, Chemoselective hydrogenation of
nitrostyrene to aminostyrene over Pd- and Rh-based intermetallic
compounds, ACS Catal. 4 (2014) 1441–1450.
[35] M. Makosch, W.I. Lin, V. Bumbálek, J. Sá, J.W. Medlin, K. Hungerbühler, J.A. Van
Bokhoven, Organic thiol modified Pt/TiO2 catalysts to control chemoselective
hydrogenation of substituted nitroarenes, ACS Catal. 2 (2012) 2079–2081.
[36] R.V. Jagadeesh, A.E. Surkus, H. Junge, M.M. Pohl, J. Radnik, J. Rabeah, H. Huan, V.
Schünemann, A. Brückner, M. Beller, Nanoscale Fe2O3-based catalysts for
selective hydrogenation of nitroarenes to anilines, Science 342 (2013) 1073–
1076.
[37] H. Wei, X. Liu, A. Wang, L. Zhang, B. Qiao, X. Yang, Y. Huang, S. Miao, J. Liu, T.
Zhang, FeOx-supported platinum single-atom and pseudo-single-atom
catalysts for chemoselective hydrogenation of functionalized nitroarenes,
Nat. Comm. 5 (2014) 5634.
[38] M.J. Beier, J.M. Andanson, A. Baiker, Tuning the chemoselective hydrogenation
of nitrostyrenes catalyzed by ionic liquid-supported platinum nanoparticles,
ACS Catal. 2 (2012) 2587–2595.
[4] K. Chu, F. Wang, Y. Tian, Z. Wei, Phosphorus doped and defects engineered
graphene for improved electrochemical sensing: synergistic effect of dopants
and defects, Electrochim. Acta 231 (2017) 557–564.
[5] Y. Cao, S. Mao, M. Li, Y. Chen, Y. Wang, Metal/porous carbon composites for
heterogeneous catalysis: old catalysts with improved performance promoted
by N-doping, ACS Catal. 7 (2017) 8090–8112.
[6] D. Liu, X.F. Chen, G.Q. Xu, J. Guan, Q. Cao, B. Dong, Y.F. Qi, C.H. Li, X.D. Mu,
Iridium nanoparticles supported on hierarchical porous N-doped carbon: an
efficient water-tolerant catalyst for bio-alcohol condensation in water, Sci.
Rep. 6 (2016) 21365.
[7] J. Liu, Y. Liu, N.Y. Liu, Y.Z. Han, X. Zhang, H. Huang, Y. Lifshitz, S.T. Lee, J. Zhong,
Z.H. Kang, Metal-free efficient photocatalyst for stable visible water splitting
via a two-electron pathway, Science 347 (2015) 970–974.
[8] H.M. Wang, H.X. Wang, Y. Chen, Y.J. Liu, J.X. Zhao, Q.H. Cai, X.Z. Wang,
Phosphorus-doped graphene and (8, 0) carbon nanotube: Structural,
electronic, magnetic properties, and chemical reactivity, Appl. Surf. Sci. 273
(2013) 302–309.
[9] F. Wang, C. Hu, J. Lian, M. Zhou, K. Wang, J. Yan, K. Jiang, Phosphorus-doped
activated carbon as a promising additive for high performance lead carbon
batteries, RSC Adv. 7 (2017) 4174–4178.
[10] L. Xin, F. Yang, S. Rasouli, Y. Qiu, Z.F. Li, A. Uzunoglu, C.J. Sun, Y. Liu, P. Ferreira,
W.Z. Li, Y. Ren, L.A. Stanciu, J. Xie, Understanding Pt nanoparticle anchoring on
graphene supports through surface functionalization, ACS Catal. 6 (2016)
2642–2653.
[11] A.E. Aksoylu, M. Madalena, A. Freitas, M.F.R. Pereira, J.L. Figueiredo, The effects
of different activated carbon supports and support modifications on the
properties of Pt/AC catalysts, Carbon 39 (2001) 175–185.
[12] G. Peng, F. Gramm, C. Ludwig, F. Vogel, Effect of carbon surface functional
groups on the synthesis of Ru/C catalysts for supercritical water gasification,
Catal. Sci. Technol. 5 (2015) 3658–3666.
[13] B.F. Machado, M. Oubenali, M. Rosa Axet, T. Trang Nguyen, M. Tunckol, M.
Girleanu, O. Ersen, I.C. Gerber, P. Serp, Understanding the surface chemistry of
carbon nanotubes: toward a rational design of Ru nanocatalysts, J Catal. 309
(2014) 185–198.
[14] G. Szöllösi, B. Török, L. Baranyi, M. Bartók, Chemoselective hydrogenation of
cinnamaldehyde to cinnamyl alcohol over Pt/K-10 catalyst, J Catal. 179 (1998)
619–623.
[15] D.J. Li, Y.S. Wu, L. Feng, L.Q. Zhang, Surface properties of SAC and its adsorption
mechanisms for phenol and nitrobenzene, Bioresour. Technol. 113 (2012)
121–126.
[39] L. Huang, P.F. Luo, W.G. Pei, X.Y. Liu, Y. Wang, J. Wang, W.H. Xing, J. Huang,
Selective hydrogenation of nitroarenes and olefins over rhodium nanoparticles
on hydroxyapatite, Adv. Synth. Catal. 354 (2012) 2689–2694.
[40] J.L. Figueiredo, M.F.R. Pereira, M.M.A. Freitas, J.J.M. Órfão, Modification of the
surface chemistry of activated carbons, Carbon 37 (1999) 1379–1389.
[41] J.L. Figueiredo, M.F.R. Pereira, M.M.A. Freitas, J.J.M. Órfão, Characterization of
active sites on carbon catalysts, Ind. Eng. Chem. Res. 46 (2007) 4110–4115.
[42] G. de la Puente, A. Centeno, A. Gil, P. Grange, Interactions between
molybdenum and activated carbons on the preparation of activated carbon-
supported molybdenum catalysts, J. Colloid Interf. Sci. 202 (1998) 155–166.
[16] S. Haydar, M.A. Ferro, Garcıa, J. Rivera Utrilla, J.P. Joly, Adsorption of p-
´
nitrophenol on an activated carbon with different oxidations, Carbon 41
(2003) 387–395.
[17] H. Tan, O.E. Tall, Z. Liu, N. Wei, T. Yapici, T. Zhan, M.N. Hedhill, Y. Han, Selective
oxidation of glycerol to glyceric acid in base-free aqueous solution at room

Q. Wu et al. / Journal of Catalysis 364 (2018) 297–307
307
[43] X.H. Lu, Y. Shen, J. He, R. Jing, P.P. Tao, A. Hu, R.F. Nie, D. Zhou, Q.H. Xia,
Selective hydrogenation of benzoic acid to cyclohexane carboxylic acid over
microwave-activated Ni/carbon catalysts, Molec. Catal. 444 (2018) 53–61.
[44] J.J. Musci, A.B. Merlo, M.L. Casella, Aqueous phase hydrogenation of furfural
using carbon-supported Ru and RuSn catalysts, Catal. Today 296 (2017) 43–50.
[45] M.A. Patel, F. Luo, M.R. Khoshi, E. Rabie, Q. Zhang, C.R. Flach, R. Mendelsohn, E.
Garfunkel, M. Szostak, H. He, P-doped porous carbon as metal free catalysts for
selective aerobic oxidation with an unexpected mechanism, ACS Nano 10
(2016) 2305–2315.
[46] G. Hasegawa, T. Deguchi, K. Kanamori, Y. Kobayashi, H. Kageyama, T. Abe, K.
Nakanishi, High-level doping of nitrogen, phosphorus, and sulfur into
activated carbon monoliths and their electrochemical capacitances, Chem.
Mater. 27 (2015) 4703–4712.
[47] S. Suzuki, Y. Ohbu, T. Mizukami, Y. Takamori, M. Morishima, H. Daimon, M.
Hiratani, Platinum–phosphorus nanoparticles on carbon supports for oxygen-
reduction catalysts, J Electrochem. Soc 156 (2009) B27.
[48] Y.C. Tong, X.Y. Zhang, Q.Y. Wang, X.J. Xu, The adsorption mechanism of
platinum on phosphorus-doped single walled carbon nanotube, Comput.
Theor. Chem. 1059 (2015) 1–6.
triarylphosphine-stabilized Pt nanoparticle catalysts by X-ray absorption
spectroscopy, J. Phys. Chem. C 112 (2008) 4961–4970.
[50] Y. Tan, X.Y. Liu, L. Zhang, A. Wang, L. Li, X. Pan, S. Miao, M. Haruta, H. Wei, H.
Wang, F. Wang, X. Wang, T. Zhang, ZnAl-hydrotalcite-supported Au25
nanoclusters as precatalysts for chemoselective hydrogenation of 3-
nitrostyrene, Angew. Chem. Int. Ed. 56 (2017) 2709–2713.
[51] K.-I. Shimizu, Y. Miyamoto, T. Kawasaki, T. Tanji, Y. Tai, A. Satsuma,
Chemoselective hydrogenation of nitroaromatics by supported gold
catalysts: mechanistic reasons of size- and support-dependent activity and
selectivity, J. Phys. Chem. C 113 (2009) 17803–17810.
[52] J. Nan, H.B. Yu, Q.S. Xue, Y.D. Li, In situ FT-IR study on hydrogenation of olefin and
aromatic on Pd-based metal catalysts, Chem. Eng. Oil Gas 38 (2009) 183–188.
[53] C. Minejima, T. Ebata, N. Mikami, C-H stretching vibrations of benzene and
toluene in their S1 states observed by double resonance vibrational
spectroscopy in supersonic jets, PCCP 4 (2002) 1537–1541.
[54] A.K. Sharma, R.B. Sunoj, Refined transition-state models for proline-catalyzed
asymmetric michael reactions under basic and base-free conditions, J. Org.
Chem. 77 (2012) 10516–10524.
[55] K.R. Kahsar, D.K. Schwartz, J.W. Medlin, Control of metal catalyst selectivity
through specific noncovalent molecular interactions, J Am. Chem. Soc. 136
(2014) 520–526.
[49] D.S. Gatewood, T.L. Schull, O. Baturina, J.J. Pietron, Y. Garsany, K.E. Swider-
Lyons, D.E. Ramaker, Characterization of ligand effects on water activation in