PtRuNi/C novel nanostructures of platinum-ruthenium island-on-Ni/Ni(OH)2 nanoparticles for the selective hydrogenation of quinoline

Article abstract of DOI:10.1016/j.jallcom.2020.155203

Ni/C was successfully synthesized via hydrazine hydrate reduction at room temperature (RT). Pt/C, Ru/C and PtRu/C were prepared via an impregnation method. PtNi/C, RuNi/C and PtRuNi/C were synthesized via a chemical replacement method. The characterization results revealed that PtRuNi nanoparticles (NPs) were highly and uniformly dispersed on carbon black in PtRuNi/C. PtRuNi/C showed a novel nanostructure in which PtRu islands (PtRu nanoclusters or PtRu binary atoms) covered Ni/Ni(OH)₂ NPs. PtRuNi/C trimetallic nanomaterial exhibited an optimum catalytic performance (turnover frequency (TOF) = 211.4 h^?1 and selectivity for the production of 1,2,3,4-tetrahydroquinoline (py-THQ) > 99%) in the selective hydrogenation of quinoline at 60 °C under 5.0 MPa H₂. The catalytic properties of PtRuNi/C were significantly improved as compared to bimetallic (PtNi/C, RuNi/C and PtRu/C) and monometallic (Ni/C, Pt/C and Ru/C) nanomaterials due to its unique nanostructure, with an observed nano-synergy effect among Pt-, Ru- and Ni-related species.

Full text of DOI:10.1016/j.jallcom.2020.155203

Journal of Alloys and Compounds 834 (2020) 155203
Contents lists available at ScienceDirect
Journal of Alloys and Compounds
journal homepage: http://www.elsevier.com/locate/jalcom
PtRuNi/C novel nanostructures of platinum-ruthenium island-on-Ni/
Ni(OH) nanoparticles for the selective hydrogenation of quinoline
2
a
a
b
a
a
c
Huan Zhang , An Pei , Jianhua Liao , Luna Ruan , Kai Yang , Jiexiang Wang ,
Lihua Zhu
a
a, d, *
, Bing Hui Chen d
College of Chemistry and Chemical Engineering, Faculty of Materials Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou,
41000, Jiang Xi, China
School of Pharmaceutical Sciences, Gannan Medical University, Ganzhou, 341000, Jiangxi, China
Fine Chemical Industry Research Institute, School of Chemistry, Sun Yat-Sen University, Guangzhou, 510275, China
Department of Chemical and Biochemical Engineering, National Engineering Laboratory for Green Productions of Alcohols-Ethers-Esters, College of
3
b
c
d
Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 6 August 2019
Received in revised form
Ni/C was successfully synthesized via hydrazine hydrate reduction at room temperature (RT). Pt/C, Ru/C
and PtRu/C were prepared via an impregnation method. PtNi/C, RuNi/C and PtRuNi/C were synthesized
via a chemical replacement method. The characterization results revealed that PtRuNi nanoparticles
12 March 2020
(
NPs) were highly and uniformly dispersed on carbon black in PtRuNi/C. PtRuNi/C showed a novel
nanostructure in which PtRu islands (PtRu nanoclusters or PtRu binary atoms) covered Ni/Ni(OH) NPs.
PtRuNi/C trimetallic nanomaterial exhibited an optimum catalytic performance (turnover frequency
Accepted 13 April 2020
Available online 17 April 2020
2
ꢀ
1
(
TOF) ¼ 211.4 h and selectivity for the production of 1,2,3,4-tetrahydroquinoline (py-THQ) > 99%) in the
Keywords:
ꢁ
selective hydrogenation of quinoline at 60 C under 5.0 MPa H
2
. The catalytic properties of PtRuNi/C were
PtRuNi/C nanomaterial
Quinoline selective hydrogenation
PtRu islands
significantly improved as compared to bimetallic (PtNi/C, RuNi/C and PtRu/C) and monometallic (Ni/C, Pt/
C and Ru/C) nanomaterials due to its unique nanostructure, with an observed nano-synergy effect among
Pt-, Ru- and Ni-related species.
1,2,3,4-Tetrahydroquinoline
©
2020 Elsevier B.V. All rights reserved.
1
. Introduction
a great challenge to find a catalyst that offers high conversion and
high selectivity for quinoline hydrogenation under mild reaction
conditions [8,9].
Catalytic hydrogenation of aromatic compounds using metallic
catalysts is regarded as one of the most important reactions in the
synthesis of fine chemicals [1e3]. 1,2,3,4-tetrahydroquinoline (py-
THQ) is an important fine chemical intermediate widely used in the
synthesis of medicines, pesticides and dyes [4e6]. The method of
quinoline selective hydrogenation to obtain py-THQ is simple with
It is well known that most catalysts for the selective hydroge-
nation of quinoline contain noble metals [10]. A synergistic effect
occurs among the various metal-related species in multimetallic
catalysts, so their catalytic performance can be improved as
compared to those of monometallic catalysts [11e13]. In the past
few decades, precious metals including platinum [14e17], gold [10],
palladium [18e20], rhodium [21], iridium [22,23] and ruthenium
[24e28] deposited on various supports (e.g., carbon and metal
oxide) have been employed in quinoline-selective hydrogenation
reactions. Recently, Yu et al. found that an Ru/OMNC-700 catalyst
100% materials utilization, which attracts wide interests of re-
searchers. Many scientists have employed high reaction tempera-
tures (100e150 C), high reaction pressures (3e6 MPa) and long
reaction times (>10 h) in quinoline hydrogenation reaction. These
conditions increase the reaction rate of quinoline hydrogenation
but decrease the selective production of py-THQ [7]. Therefore, it is
ꢁ
ꢀ1
showed excellent catalytic activity and provided a TOF of 70.0 h
for quinoline hydrogenation with >99% THQ selectivity under mild
ꢁ
conditions (50 C and 1.0 MPa H
2
) [29]. In the study of Zhang et al.,
the as-prepared Pd@CIL-900 catalyst had large surface area, real-
*
Corresponding author. College of Chemistry and Chemical Engineering, Faculty
ꢀ1
izing a TOF of 179.2 h for quinoline hydrogenation and high
of Materials Metallurgy and Chemistry, Jiangxi University of Science and Technol-
ogy, Ganzhou 341000, Jiang Xi, China.
ꢁ
selectivity for THQ production (>99%) at 80 C under 0.1 MPa H
2
E-mail address: zhulihua156@163.com (L. Zhu).
[30]. Most of the above studies investigated the catalytic
https://doi.org/10.1016/j.jallcom.2020.155203
0925-8388/© 2020 Elsevier B.V. All rights reserved.

2
H. Zhang et al. / Journal of Alloys and Compounds 834 (2020) 155203
performance of monometallic or bimetallic catalysts for quinoline
hydrogenation. It is of great significance to find a highly efficient
trimetallic catalyst that has high selectivity for quinoline hydro-
genation under mild reaction conditions [31e34].
Herein, we successfully prepared Ni/C samples at RT via a simple
strategy of hydrazine hydrate reduction and the corresponding
PtNi/C, RuNi/C and PtRuNi/C catalysts by a chemical replacement
strategy. The effect of reaction temperature on the catalytic
behavior of the PtRuNi/C trimetallic nanocatalyst for quinoline
hydrogenation was investigated. The reasons for the differences in
the catalytic performances of the monometallic (Ni/C, Pt/C and Ru/
C), bimetallic (PtRu/C, PtNi/C and RuNi/C) and trimetallic (PtRuNi/C)
catalysts in the selective hydrogenation of quinoline are discussed.
The nanostructures of the as-prepared catalysts were characterized
by various analytical methods, including XRD, TEM, SEM, HAADF-
STEM, STEM-EDX mapping and line-scanning, XPS and HS-LEIS.
PtRuNi/C exhibited outstanding catalytic performance in quino-
line hydrogenation, providing >99% selectivity for the production
Fig. 2. (a) HAADF-STEM image of PtRuNi/C and (b) PtRuNi nanoparticles size distri-
bution of PtRuNi/C.
react at RT for 18.5 h. When the reaction was complete, the black
product was collected by filtration and washed several times with
deionized water and absolute ethanol. The black solid, which was
ꢀ1
of py-THQ and 211.4 h TOF under mild reaction conditions (re-
ꢁ
ꢁ
action temperature ꢀ60 C and 5.0 MPa H
2
).
designated Ni/C, was dried in a vacuum drying oven at 60 C for 6 h.
Preparation of PtNi/C and RuNi/C: Ni/C (0.3000 g) and a specific
2
. Experimental section
3 3 2
amount of aqueous RuCl solution (1.0000 g RuCl $xH O in 250 mL
deionized water) were mixed together and magnetically stirred for
6 h. The catalyst was collected by filtration and washed several
times, the resulting black solid, which was designated RuNi/C, was
2.1. Materials and reagents
ꢁ
All chemical reagents were of analytical grade and were pur-
chased from Shanghai Sinopharm Chemical Reagent Co., Ltd., The
reagents included nickel(II) chloride hexahydrate (NiCl $6H O),
ethanol, hexane, sodium hydroxide, hydrazine hydrate (85 wt%
$H O), carbon black (BP-2000), ruthenium trichloride hydrate
RuCl $xH O), chloroplatinic acid hexahydrate (H PtCl $6H O),
quinoline (C N), 1,2,3,4-tetrahydroquinoline (C 11N), 5,6,7,8-
tetrahydroquinoline (C 11N), decahydroquinoline (C 17N), dec-
ahydroisoquinoline (C 17N) and deionized water. All chemicals
were used without further purification.
dried in a vacuum drying oven at 60 C for 6 h. The steps in the
synthesis of the PtNi/C catalyst were similar to those of RuNi/C via a
chemical replacement method [36e40].
Preparation of PtRu/C: PtRu/C catalyst with 1.0 wt% Pt and 1.2 wt
% Ru loading was prepared by incipient wetness impregnation
2
2
N
(
2
H
4
2
method. A pre-calculated amount of aqueous H
(1.0000 g H PtCl $6H O in 250 mL deionized water) and aqueous
RuCl solution were placed in a beaker, and deionized water
2 6
PtCl solution
3
2
2
H
2
2
9
H
7
9
2
2
2
9
H
9
H
3
H
(100 mL) was added. Carbon black (BP-2000, 0.3000 g) was added
to the mixed solution under strong agitation. The mixture was
9
ꢁ
stirred continuously at 80 C until almost all of the water had
ꢁ
2.2. Preparation of the catalysts
evaporated. It was then placed in a blast oven and dried at 110 C for
3
h to obtain a dry sample. The sample was calcined under mixed
ꢀ1
ꢁ
Preparation of Ni/C: Ni/C was synthesized at room temperature
gas (90%N
2
þ10%H
2
, 20 mL min ) at 400 C for 2 h at a heating rate
ꢁ
ꢀ1
(
RT) via a hydrazine hydrate reduction [35]. Typically, 0.4500 g
of 2 C min , the product was designated PtRu/C. The steps in the
synthesis of Pt/C (with 2% Pt loading) and Ru/C (with 2.4% Ru
loading) catalysts were similar to those of PtRu/C.
nickel(II) chloride hexahydrate was added to a solution prepared by
mixing 82.5 mL deionized water with 12.5 mL anhydrous ethanol.
After 10 min magnetic stirring at RT, a green transparent solution
was obtained, 20 mL aqueous NaOH solution (containing 1.8130 g
NaOH) was then poured into the above-mentioned solution, and
the mixture was stirred for 10 min. Then, 25 mL hydrazine hydrate
was transferred to the above mixture as a reductant, and the
mixture was magnetically stirred for another 10 min. Next, 1.2500 g
carbon black (BP-2000) was injected into the mixture, the mixture
was stirred for 10 min, transferred to a Teflon cup, and allowed to
Synthesis of PtRuNi/C: A pre-calculated amount of aqueous
H
2
PtCl
0.3000 g Ni/C was added. After stirring for 2 h, a measured amount
of aqueous RuCl solution was added, and stirring was continued
2
solution was diluted in 200 mL deionized water, and
3
for an additional 2 h. After filtration and washing with ethanol and
deionized water, a black solid was obtained. The solid powder was
ꢁ
dried at 60 C for 6 h under vacuum and was designated PtRuNi/C.
The actual loading of Pt in PtNi/C and PtRuNi/C was 2% and 1%,
Fig. 1. Powder XRD patterns of the samples (A) (a) Ni/C, (b) Ru/C and (c) RuNi/C; (B) (a) Ni/C, (b) Pt/C and (c) PtNi/C; (C) (a) Ni/C, (b) PtRu/C and (c) PtRuNi/C.

H. Zhang et al. / Journal of Alloys and Compounds 834 (2020) 155203
3
Fig. 3. TEM images of PtRuNi/C at (a) 200 nm, (b) 100 nm, (c) 50 nm and (d) 10 nm scale, respectively.
respectively. The ruthenium mass fraction in RuNi/C and PtRuNi/C
2.3. Characterization
was 2.4 wt% and 1.2% wt%, respectively. The metal content of as-
obtained catalysts was determined by inductively coupled plasma
atomic mass spectrometry (Agilent ICP-MS 4500-300).
X-ray powder diffraction (XRD) measurements of as-
synthesized samples were performed on Rigaku Ultima IV X-ray
diffractometer with Cu Ka radiation as the X-ray resource
Fig. 4. (a) SEM image of PtRuNi/C and (b) SEM-EDX spectrum of PtRuNi/C; (c) SEM image of RuNi/C and (d) SEM-EDX spectrum of RuNi/C.

4
H. Zhang et al. / Journal of Alloys and Compounds 834 (2020) 155203
n
in ꢀ n
ðquinolineÞ
out
ðquinolineÞ
in
ðquinolineÞ
X ¼
ꢂ 100%
n
ꢀ
ꢁ . ꢀ
ꢁ
TOF ¼
n
ꢂ X
n
ꢂ t ꢂ D
ðnoble metalÞ
ðquinolineÞ
where X is the conversion of quinoline and nnoble metal, t and D
represent the total moles of noble metal, the reaction time and the
dispersion, respectively. The dispersion can be calculated as
follows:
D ¼ (6n
s
M)/(
p
rNd )
Fig. 5. (a) HAADF-STEM image of PtRuNi/C, (b) STEM-EDX elemental line-scanning
profile of an individual PtRuNi nanoparticle along the red arrow direction, red (Pt),
blue (Ru) and black (Ni). (For interpretation of the references to colour in this figure
legend, the reader is referred to the Web version of this article.)
Where n
s
signifies the number of metal atoms on the surface per
19
ꢀ2
19
ꢀ2
), M repre-
unit area (Pt: 1.12 ꢂ 10
m
and Ru: 1.63 ꢂ 10
m
g
ꢀ
1
sents the atomic mass of Pt or Ru (195.08
mol
and
ꢀ
1
101.07 g mol for Pt and Ru, respectively).
r
represents the density
(l
¼ 0.154 nm, 40 kV and 30 mA). Transmission electron micro-
ꢀ3
23
ꢀ3
of the metal (
rPt ¼ 21.45 g cm
,
r
Ru ¼ 12.1 g cm ). N is the
scopy images were captured on an FEI TECNAI F30 electron mi-
croscope at 300 kV acceleration voltage. X-ray photoelectron
spectra (XPS) of the samples were recorded on a PHI Quantum 2000
ꢀ1
Avogadro’s number (6.023 ꢂ 10 mol ), and d
p
is the average size
ꢀ9
of the metallic particles (d
p
¼ 6.52 ꢂ 10 m, from Fig. 3).
Scanning ESCA Microprobe analyzer with Al
Ka irradiation
3. Results and discussions
(hn
¼ 1486.6 eV), the binding energy of C 1s (284.6 eV) was used as
the internal standard. High-angle annular dark field scanning
transmission electron microscopy (HAADF-STEM) images and
STEM energy dispersive X-ray spectroscopy (STEM-EDX) elemental
mapping and line-scanning results of the catalysts were obtained
using a TECNAI F30 electron microscope at 300 kV acceleration
voltage. High-sensitivity low-energy ion scattering (HS-LEIS)
spectra of the catalysts were obtained on an IonTOF Qtac100 low-
energy ion scattering analyzer. The low ion flux was
3
.1. Characterization results of the samples
Fig. 1 shows the XRD patterns of as-synthesized samples that
were used to analyze the crystallite phase structures and dispersion
of the catalysts. Fig. 1A displays the XRD patterns of Ni/C, Ru/C and
RuNi/C. The diffraction peaks at 2
and 62.7 are assigned to the (001), (110), (101), (102), (110) and
(111) planes of Ni(OH)
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
q
¼ 19.2 , 33.1 , 38.1 , 52.1 , 59.1
ꢁ
ꢀ þ þ
2
4
20
2
, respectively (JCPDS card No. 04-0117) [43].
1
325 pA cm (3 keV He spectra). Ne ions with a kinetic en-
ꢁ
ꢀ
2
In addition, the diffraction peak at 2
q
¼ 44.4 corresponds to the
ergy of 5 keV were applied at a low ion flux of 1600 pA cm (5 keV
4
þ
ꢁ
(111) facet of fcc Ni (JCPDS card No. 04-0850) [44,45]. XRD patterns
indicate that Ni and Ni(OH) crystalline phases are present in Ni/C.
After ruthenium was supported on Ni/C (Fig. 1Ac), the intensity of
Ni(111) and Ni(OH) diffraction peaks decreased slightly. A possible
Ne spectra). The scattering angle was 145 . Scanning electron
2
microscopy (SEM) images and SEM-EDX spectra of the catalysts
were collected in a LEO-1530 scanning electron microscope.
2
reason for this is that ruthenium atoms replace some nickel atoms
during the synthesis of RuNi/C. Similar conclusions could be drawn
by analyzing the XRD patterns of the Ni/C, Pt/C and PtNi/C catalysts
2.4. Catalytic activity test
(Fig. 1B). Fig. 1C shows the XRD patterns of Ni/C, PtRu/C and PtRuNi/
The catalytic performance of as-synthesized catalysts for quin-
C. Only the characteristic diffraction peaks of Ni(OH) and Ni appear
2
oline hydrogenation was tested in an MS-50-316 L stainless steel
autoclave. In the experiment, 10 mL ethanol quinoline solution
in Fig. 1C, while the characteristic diffraction peaks associated with
Ru and Pt are not observed. This is probably because Ru and Pt are
(
0.69 wt%) and 0.0500 g catalyst was placed in the autoclave. After
2
coated on Ni/Ni(OH) nanoparticles in the form of particles too
the reaction device was installed, air in the reactor was replaced
small to be observed or as an amorphous coating.
with hydrogen, the reactor was then filled with hydrogen until the
Fig. 2 displays a HAADF-STEM image of PtRuNi/C (Fig. 2a) and
shows the size distribution of PtRuNi nanoparticles (Fig. 2b). It
demonstrates that the PtRuNi nanoparticles are highly dispersed on
the catalyst support (carbon black). Fig. 2b shows that PtRuNi
nanoparticles with an average diameter of 6.52 nm are obtained
and that the particle size distribution is narrow with small particle
size.
To further explore the nanostructure and morphology of the
catalyst, the PtRuNi/C catalyst was observed by TEM. The four TEM
images in Fig. 3 show the PtRuNi/C catalyst at various magnifica-
tions. In the TEM images of PtRuNi/C, many small black spots can be
observed on the surface of the support (Fig. 3a and b), and the
distribution of the PtRuNi metal nanoparticles is seen to be very
uniform.
ꢀ1
pressure reached 5.0 MPa and the stirring rate reached 870 r min
.
The reaction was conducted at the specified temperature (e.g.,
ꢁ
1
00 C) for a defined period of time (e.g., 1 h). When the reaction
was finished, the sample was quickly cooled to room temperature.
The filtered liquid products were analyzed by gas chromatography
on Shimadzu system using a DB-35 (60 m ꢂ 0.32 mm) capillary
column and a flame ionization detector (FID), and the products
were identified by gas chromatography ~ mass spectrometry using
a Shimadzu system.
The catalytic properties of as-obtained catalysts were deter-
mined by calculating their conversion, selectivity and turnover
frequency (TOF). The Pt and Ru metal loadings were determined by
ICP-MS and the metal atoms were equally distributed on the sur-
face of catalysts. According to the literature [41,42], the dispersion
of the PtRu nanoparticles was calculated according to the equation
below. The Pt and Ru metal loadings were determined by ICP-MS,
and the metal atoms were found to be equally distributed on the
surface of the catalysts.
Typical SEM images of the PtRuNi/C and RuNi/C catalysts and
their SEM-EDX spectra are shown in Fig. 4. The images show that
PtRuNi and RuNi nanoparticles are too small to be detected by SEM,
demonstrating that the metallic nanoparticles are highly dispersed.
To further investigate the distribution of elements in the catalysts,

H. Zhang et al. / Journal of Alloys and Compounds 834 (2020) 155203
5
Fig. 6. Ni 2p XPS spectra of (a) Ni/C, (b) PtNi/C, (c) RuNi/C and (d) PtRuNi/C.
Fig. 7. Pt 4f XPS spectra for (a) Pt/C, (b) PtRu/C, (c) PtNi/C and (d) PtRuNi/C.
the PtRuNi/C and RuNi/C catalysts were characterized by SEM-EDX.
Platinum, ruthenium, oxygen, nickel and carbon are found in the
EDX spectrum of PtRuNi/C (Fig. 4b). In addition, elemental ruthe-
nium, oxygen, nickel and carbon are detected in the EDX spectrum
of the RuNi/C catalyst (Fig. 4d).
line-scanning result are shown in Fig. 5. In Fig. 5a, a number of
highly dispersed, bright nanoparticles are visible on the support.
Fig. 5b presents a STEM-EDX elemental line-scanning image in
which we can see that Ru, Pt and Ni occur together in selected
individual PtRuNi nanoparticles and that the Ru and Pt are centrally
distributed on particles with a diameter of 4e6 nm. Areas
HAADF-STEM image of PtRuNi/C and its STEM-EDX elemental

6
H. Zhang et al. / Journal of Alloys and Compounds 834 (2020) 155203
Fig. 8. Ru 3p XPS spectra for (a) Ru/C, (b) PtRu/C, (c) RuNi/C and (d) PtRuNi/C.
containing all three elements do not appear, consistent with the
previous XRD analysis results indicating that the PtRuNi alloy does
not exist in the PtRuNi/C catalyst.
The chemical states and surface compositions of the elements in
Ni/C, PtNi/C, RuNi/C and PtRuNi/C were analyzed using the XPS
technique. The Ni 2p XPS spectra of the catalysts are presented in
Fig. 6. The Ni 2p3/2 peaks appearing at binding energies of 852.7,
the Ru 2p XPS and Pt 4f XPS spectra shows that the ratio of oxidized
Pt in all Pt-related species is much larger than that of oxidized Ru in
all Ru-related species. This suggests that more Pt atoms than Ru
atoms are located on the surface, resulting in Pt being more easily
oxidized.
The atomic content on the outermost surface of the catalysts
was characterized by high-sensitivity low-energy ion scattering.
4
þ
20
þ
8
53.9, 855.4 and 857.1 eV belong to Ni(0), NiO, Ni(OH)
2
and NiOOH
3 keV He and 5 keV Ne HS-LEIS spectra of the as-prepared
catalysts are shown in Fig. 9. According to Fig. 9Ac, there are four
types of atoms (carbon, oxygen, nickel and platinum) on the surface
of PtNi/C, and the content of carbon and oxygen atoms on the
surface of each catalyst is almost the same. However, in the 3 keV
species, respectively [46e48]. Comparison of the peak areas shows
that the Ni species on the surface of the above-mentioned four
catalysts exists primarily in the form of oxidized Ni, with a small
amount of Ni(0) species. Combined with the XRD characterization
4
þ
results presented above, the results show that Ni(OH)
dominant Ni species present.
2
is the
He HS-LEIS spectrum of Pt/C (Fig. 9Ab), no signal from Pt atoms is
found, probably because high-sensitivity low-energy ion scattering
4
þ
Fig. 7 shows the Pt 4f XPS spectra of Pt/C, PtRu/C, PtNi/C and
PtRuNi/C. The binding energies observed at 71.5, 72.4 and 73.5 eV
(3 keV He ) is less sensitive to heavy atoms. Moreover, in the 3 keV
4
þ
He HS-LEIS spectra, the Ni signal of the Ni/C catalyst is much
2
þ
4þ
can be assigned to Pt(0), Pt and Pt , respectively. In the Pt 4f5/2
stronger than that of the other catalysts, mainly because some Ni
atoms were replaced with Pt atoms during the synthesis of the
2þ
4þ
XPS spectra, the Pt(0), Pt and Pt species have binding energies
of 74.9, 75.8 and 76.9 eV, respectively [49e51]. Through calculation
and comparison of each peak area, we find that Pt exists primarily
2
0
þ
PtNi/C catalyst. Fig. 9Fc (5 keV Ne HS-LEIS spectra for PtRuNi/C)
shows that the intensity of the Pt atom signal is much stronger than
that of the Ru atom signal, indicating either that Pt atoms have
higher dispersion than Ru atoms on the surface of the PtRuNi/C
catalyst or that most Ru atoms are covered by Pt atoms. The above
results are generally consistent with the results obtained with XPS.
To further investigate the microstructure and elemental distri-
bution of PtRuNi, the PtRuNi/C sample was characterized by
HAADF-STEM and STEM-EDX elemental mapping analysis. Fig. 10a
shows a HAADF-STEM image of the PtRuNi/C catalyst. Many
metallic nanoparticles are observed on the surface of the PtRuNi/C
catalyst. Fig. 10bed shows the STEM-EDX mappings of Ni (red), Pt
(dark cyan) and Ru (yellow) elements, respectively, the Ni signal is
clearly much stronger than that of Ru and Pt, and the intensity of Pt
is very difficult to distinguish because the Pt loading is low. It is
noted that the distribution of Ni element does not overlap that of Pt
and Ru elements. Taken together with the other characterization
in the form of Pt2 . The main reason for this is that Pt is located on
the surface of the catalysts and is thus easily oxidized in air.
Interestingly, the peak area of Pt(0) in Fig. 7a (Pt/C) and Fig. 7b
þ
(
(
PtRu/C) are much larger than those in Fig. 7c (PtNi/C) and Fig. 7d
PtRuNi/C), this may be due to the effect of the thermal reduction in
9
0%N
2
þ10%H
2
for Pt/C and PtRu/C and greater Pt dispersion in the
PtNi/C and PtRuNi/C catalysts.
The Ru 3p XPS spectra of the Ru/C, PtRu/C, RuNi/C and PtRuNi/C
catalysts are displayed in Fig. 8. The binding energies at 462 and
4
þ
4
64.2 eV are assigned to Ru(0) and Ru species, respectively [52].
4
þ
By calculating the peak areas associated with the Ru(0) and Ru
species in the Ru 3p3/2 XPS line, Ru species exists preferably in the
form of Ru4 rather than Ru(0). This is because Ru(0) is oxidized
under air, the results therefore indicate that there are Ru atoms on
the surfaces of the catalysts containing ruthenium. A comparison of
þ

H. Zhang et al. / Journal of Alloys and Compounds 834 (2020) 155203
7
Fig. 9. (A) 3 keV 4Heþ and (D) 5 keV Ne HS-LEIS spectra for (a) Ni/C, (b) Pt/C and (c) PtNi/C; (B) 3 keV 4He and (E) 5 keV 20Ne HS-LEIS spectra for (a) Ni/C, (b) Ru/C and (c) RuNi/
20
þ
þ
þ
4
þ
20
þ
C; (C) 3 keV He and (F) 5 keV Ne HS-LEIS spectra for (a) Ni/C, (b) PtRu/C and (c) PtRuNi/C.
results presented above, it can be inferred that PtRu islands are
loaded on the surface of the Ni/Ni(OH) nanoparticles (PtRu island-
on-Ni/Ni(OH) NPs).
decahydroisoquinoline. Based on analysis of data obtained for the
2
catalysis of quinoline hydrogenation, PtRuNi/C catalyst exhibited
excellent catalytic properties and high yield of py-THQ in this re-
2
ꢀ
1
action (yield of py-THQ
¼
69.4%, TOF
¼
329.3
h ,
3.2. Catalytic activity results
conversion ¼ 100%). The improved catalytic performance of
PtRuNi/C catalyst in the hydrogenation reaction may be due to a
synergistic effect among Pt-, Ru- and Ni-related species. It has been
reported that supported catalysts containing various noble metals
can catalyze the hydrogenation of quinolone under a variety of
conditions. PtRuNi/C described in this work exhibited relatively
excellent catalytic performance compared to previously reported
catalysts.
The catalytic performance of different catalysts for quinoline
selective hydrogenation is shown in Table 1. Quinoline hydroge-
ꢁ
nation reactions were performed at 100 C under 5.0 MPa H
2
for
1
h. When quinoline hydrogenation was catalyzed by the Ni/C
catalyst, no products were formed under the investigated reaction
conditions (entry 1 in Table 1). After platinum was supported on the
Ni/C sample, both quinoline conversion and TOF increased syn-
The catalytic performance of the PtRuNi/C catalyst in quinoline
hydrogenation at different reaction temperatures is shown in
ꢀ
1
chronously (conversion ¼ 68.8%, TOF ¼ 447.7 h , yield of py-
THQ ¼ 63.3%) (entry 4 in Table 1). The TOF of the Pt/C and Ru/C
catalysts was low with low yields to the products (py-THQ, bz-THQ,
decahydroquinoline and decahydroisoquinoline) (Table 1, entries 2,
ꢁ
Table 2. At a reaction temperature of 25 C, the conversion of
quinoline was only 1.1%, with 1.1% yield of py-THQ. Quinoline
conversion increased (100%) when the reaction temperature was
ꢁ ꢁ
3
). Furthermore, Pt/C provided 15.6% yield of py-THQ. The main
increased from 25 C to 80e100 C. TOF of the PtRuNi/C catalyst for
ꢀ
1
product of quinoline hydrogenation over the Ru/C catalyst was
quinoline hydrogenation gradually increased from 3.6 h to 329.3

8
H. Zhang et al. / Journal of Alloys and Compounds 834 (2020) 155203
Fig. 11. Stability results of the PtRuNi/C catalyst for quinoline selective hydrogenation.
Reaction conditions: ethanol quinoline solution-10 mL, reaction time-1 h, H pressure-
.0 MPa.
2
5
production of py-THQ. It can be concluded that PtRuNi/C catalyst
shows the optimum catalytic performance in the selective hydro-
ꢁ
1
genation of quinolone at 60 C (selectivity for the production of py-
ꢀ
THQ > 99%, TOF ¼ 211.4 h , yield of py-THQ ¼ 63.5%). Moreover,
the stability of PtRuNi/C for quinoline hydrogenation was also
investigated, and the results are displayed in Fig. 11. It was found
that selectivity for the production of py-THQ remained above 99%
and that the yield of py-THQ was almost unchanged, indicating that
the PtRuNi/C catalyst was very stable under the investigated reac-
tion conditions.
Fig. 10. (a) HAADF-STEM image of PtRuNi/C and STEM-EDX mappings of (b) Ni (red),
(
c) Pt (dark cyan) and (d) Ru (yellow), respectively. (For interpretation of the references
to colour in this figure legend, the reader is referred to the Web version of this article.)
h
ꢀ1. The selectivity for the production of py-THQ decreased, but the
yield of py-THQ only slightly changed at reaction temperatures
ꢁ
ꢁ
ranging from 60 C to 100 C. The main reason for this may be that
as the temperature increased, py-THQ was also further hydroge-
nated, yielding other products and reducing the selective
4. Conclusions
Ni/C was prepared at RT via hydrate hydrazine reduction, and Pt
and Ru were gradually loaded on the Ni/C in a chemical
Table 1
a
Catalytic performance of different catalysts for quinoline selective hydrogenation .
Xb (%)
Y1 (%)
c
S1d (%)
Y2 (%)
c
S2d (%)
Y3 (%)
c
S3d (%)
Y4 (%)
c
S4d (%)
ꢀ1
TOF (h )
Entry
Catalyst
t (h)
1
2
3
4
5
6
7
Ni/C
Pt/C
Ru/C
PtNi/C
RuNi/C
PtRu/C
PtRuNi/C
Pt/TiO
nanoRu@hectorite
1
1
1
1
1
1
1
6
3
0
0
0
93.2
7.7
91.9
58.9
16.0
69.4
>99
>99
0
0
0
0.9
0.7
0
1.4
e
0
0
0
1.3
1.3
0
1.4
<1
<1
0
0
0
0
e
16.8
32.3
68.8
55.1
87.1
100
>99
99.6
15.6
2.5
63.3
32.5
13.9
69.4
e
0.6
6.8
2.5
3.6
21.9
10.9
e
3.3
21.1
3.7
6.5
25.1
10.9
<1
0.6
23.1
2.1
18.3
51.3
18.3
e
3.5
71.2
3.1
33.3
58.9
18.3
e
33.5
67.9
447.7
115.8
286.9
329.3
5.8
e
8
9
2
-ED
f
e
e
e
e
e
e
222
a
ꢁ
Reaction conditions: ethanol quinoline solution-10 mL, catalyst-0.0500 g, reaction temperature-100 C, reaction time-1 h, H
2
pressure-5.0 MPa.
b
c
d
e
f
Conversion of quinoline.
Y1, Y2, Y3 and Y4 represent the yield to py-THQ, bz-THQ, decahydroquinoline, decahydroisoquinoline, respectively.
S1, S2, S3 and S4 represent the selectivity to py-THQ, bz-THQ, decahydroquinoline, decahydroisoquinoline, respectively.
Reaction conditions: quinoline (0.1 mmol), catalyst (20 mg, N,N -(ethane-1,2-diyl)diformamide (ED)-reducing agent), T (30 C), H
0
ꢁ
2
pressure (1 MPa), solvent (toluene) [14].
ꢁ
Molar ratio of substrate to metal (665), T (100 C), H
2
pressure (3 MPa), solvent (water) [6].
Table 2
Catalytic performance of PtRuNi/C for quinoline hydrogenation at different reaction temperatures .
a
ꢁ
Xb (%)
c
S1d (%)
c
S2d (%)
c
S3d (%)
c
S4d (%)
ꢀ1
TOF (h )
Temperature ( C)
Y1 (%)
Y2 (%)
Y3 (%)
Y4 (%)
2
4
6
8
5
0
0
0
1.1
6.1
64.2
100
1.1
5.4
63.5
65.5
100
88.7
>99
65.5
0
0
0
24.8
0
0
0
24.8
0
0
0
3.2
0
0
0
3.2
0
0
3.6
0.7
<1
6.5
11.3
<1
6.5
20.1
211.4
329.3
a
b
c
Reaction conditions: ethanol quinoline solution-10 mL, PtRuNi/C catalyst-0.0500 g, reaction time-1 h, H
Conversion of quinoline.
Y1, Y2, Y3 and Y4 represent the yield to py-THQ, bz-THQ, decahydroquinoline, decahydroisoquinoline, respectively.
S1, S2, S3 and S4 represent the selectivity to py-THQ, bz-THQ, decahydroquinoline, decahydroisoquinoline, respectively.
2
pressure-5.0 MPa.
d

H. Zhang et al. / Journal of Alloys and Compounds 834 (2020) 155203
9
replacement reaction to form a PtRuNi/C trimetallic catalyst. PtNi/C
and RuNi/C bimetallic catalysts were obtained using the same
preparation method. The morphology, particle size, element dis-
tribution, and nanostructures of the PtNi, RuNi and PtRuNi nano-
particles were characterized by XRD, XPS, TEM, HAADF-STEM,
STEM-EDX elemental mapping and line-scanning and HS-LEIS
analysis. The results showed that PtRuNi/C has a novel nano-
for highly chemoselective hydrogenation of quinoline under mild conditions,
J. Catal. 297 (2013) 272e280.
6] B. Sun, D. Carnevale, G. Süss-Fink, Selective N-cycle hydrogenation of quino-
lines with sodium borohydride in aqueous media catalyzed by hectorite-
supported ruthenium nanoparticles, J. Organomet. Chem. 821 (2016)
[
197e205.
[
[
7] B. Sun, F.A. Khan, A. Vallat, G. Süss-Fink, Nano Ru@hectorite: a heterogeneous
catalyst with switchable selectivity for the hydrogenation of quinoline, Appl.
Catal., A 467 (2013) 310e314.
8] M.M. Dell’Anna, V.F. Capodiferro, M. Mali, D. Manno, P. Cotugno, A. Monopoli,
P. Mastrorilli, Highly selective hydrogenation of quinolines promoted by
recyclable polymer supported palladium nanoparticles under mild conditions
in aqueous medium, Appl. Catal., A 481 (2014) 89e95.
structure in which PtRu islands are supported on Ni/Ni(OH)
nanoparticles (PtRu island-on-Ni/Ni(OH) NPs). PtRuNi/C exhibited
the optimum catalytic performance (selectivity for the production
2
2
ꢀ
1
[9] L. Ye, Y. Yamamoto, A.I. Almansour, N. Arumugam, R.S. Kumar, M. Bao, Un-
supported nanoporous palladium-catalyzed chemoselective hydrogenation of
of py-THQ > 99% and TOF ¼ 329.3 h ) for selective quinolone
hydrogenation under mild reaction conditions (5.0 MPa H
2
and
2
quinolines: heterolytic cleavage of H molecule, Chin, J. Catal. 39 (2018)
1746e1752.
ꢁ
6
0 C). The PtRuNi/C trimetallic nanocatalyst showed significantly
[
10] D. Ren, L. He, L. Yu, R.S. Ding, Y.M. Liu, Y. Cao, H.-Y. He, K.-N. Fan, An unusual
chemoselective hydrogenation of quinoline compounds using supported gold
catalysts, J. Am. Chem. Soc. 134 (2012) 17592e17598.
[11] L. Zhu, J. Zheng, C. Yu, N. Zhang, Q. Shu, H. Zhou, Y. Li, B.H. Chen, Effect of the
thermal treatment temperature of RuNi bimetallic nanocatalysts on their
improved catalytic properties as compared to bimetallic (PtNi/C,
RuNi/C and PtRu/C) and monometallic (Ni/C, Pt/C and Ru/C) nano-
catalysts due to the synergistic effect among platinum-, ruthenium-
and nickel-related species originated from the novel PtRu island-
catalytic performance for benzene hydrogenation, RSC Adv.
3110e13119.
6 (2016)
2
on-Ni/Ni(OH) NPs nanostructure.
1
[
12] W. Chen, D. Li, C. Peng, G. Qian, X. Duan, D. Chen, X. Zhou, Mechanistic and
kinetic insights into the Pt-Ru synergy during hydrogen generation from
ammonia borane over PtRu/CNT nanocatalysts, J. Catal. 356 (2017) 186e196.
13] X. Shi, H. Yu, S. Gao, X. Li, H. Fang, R. Li, Y. Li, L. Zhang, X. Liang, Y. Yuan,
Synergistic effect of nitrogen-doped carbon-nanotube-supported Cu-Fe cata-
lyst for the synthesis of higher alcohols from syngas, Fuel 210 (2017)
Declaration of competing interest
[
The authors declare that no conflicts of interest to this work.
CRediT authorship contribution statement
2
41e248.
14] S. Li, Y. Yang, Y. Wang, H. Liu, J. Tai, J. Zhang, B. Han, A route to support Pt sub-
nanoparticles on TiO and catalytic hydrogenation of quinoline to 1,2,3,4-
tetrahydroquinoline at room temperature, Catal. Sci. Technol. (2018)
314e4317.
[
2
Huan Zhang: Formal analysis, Data curation, Methodology,
Software, Investigation, Writing - original draft. An Pei: Formal
analysis, Data curation, Validation, Visualization, Software. Jianhua
Liao: Writing - review & editing, Supervision. Luna Ruan: Formal
analysis, Data curation, Validation, Visualization. Kai Yang: Formal
analysis, Data curation, Validation. Jiexiang Wang: Formal analysis,
Writing - review & editing. Lihua Zhu: Conceptualization, Super-
vision, Visualization, Resources, Project administration, Funding
acquisition, Writing - review & editing. Bing Hui Chen: Writing -
review & editing, Supervision.
8
4
[
15] X. Xue, M. Zeng, Y. Wang, Highly active and recyclable Pt nanocatalyst for
hydrogenation of quinolines and isoquinolines, Appl. Catal., A 560 (2018)
37e41.
16] D. Ge, L. Hu, J. Wang, X. Li, F. Qi, J. Lu, X. Cao, H. Gu, Reversible hydrogenation-
oxidative dehydrogenation of quinolines over a highly active Pt nanowire
catalyst under mild conditions, ChemCatChem 5 (2013) 2183e2186.
[17] S. Zhang, Z. Xia, T. Ni, Z. Zhang, Y. Ma, Y. Qu, Strong electronic metal-support
interaction of Pt/CeO enables efficient and selective hydrogenation of quin-
olines at room temperature, J. Catal. 359 (2018) 101e111.
18] Y. Ren, Y. Wang, X. Li, Z. Zhang, Q. Chi, Selective hydrogenation of quinolines
into 1,2,3,4-tetrahydroquinolines over a nitrogen-doped carbon-supported Pd
catalyst, New J. Chem. 42 (2018) 16694e16702.
[
2
[
[
19] N. Hashimoto, Y. Takahashi, T. Hara, S. Shimazu, T. Mitsudome, T. Mizugakiet,
K. Jitsukawa, K. Kaneda, Fine tuning of Pd0 nanoparticle formation on hy-
droxyapatite and its application for regioselective quinoline hydrogenation,
Chem. Lett. 39 (2010) 832e834.
Acknowledgments
This research was supported by the National Natural Science
Foundation of China (Grant No. 21763011), Natural Science Foun-
dation of Jiangxi Province for Distinguished Young Scholars (Grant
No. 20192BCB23015), Youth Jinggang Scholars Program in Jiangxi
Province ([2019]57), China Postdoctoral Science Foundation (Grant
No. 2018M642597), Foundation of State Key Laboratory of Coal
Conversion (Grant No. J20-21-609), Research Foundation of the
Education Bureau of Jiangxi Province of China (GJJ190429), Post-
doctoral Science Foundation of Jiangxi Province of China, Program
of Qingjiang Excellent Young Talents, Jiangxi University of Science
and Technology (JXUSTQJBJ2019002), Program of Technology
Innovation Talents of Ganzhou. The support of these organizations
is gratefully acknowledged.
[
20] M.M. Dell’Anna, G. Romanazzi, S. Intini, A. Rizzuti, C. Leonelli, A.F. Piccinni,
P. Mastrorilli, A polymer supported palladium(II) b-ketoesterate complex as
active and recyclable pre-catalyst for selective reduction of quinolines in
water with sodium borohydride, J. Mol. Catal. A 402 (2015) 83e91.
21] M. Niu, Y. Wang, P. Chen, D. Du, J. Jiang, Z. Jin, Highly efficient and recyclable
rhodium nanoparticle catalysts for hydrogenation of quinoline and its de-
rivatives, Catal. Sci. Technol. 5 (2015) 4746e4749.
[
[
22] B.C. Ledesma, M.L. Martínez, A.R. Beltramone, Iridium-supported SBA-15
modified with Ga and Al as
a highly active catalyst in the hydro-
denitrogenation of quinoline, Catal. Today (2018), https://doi.org/10.1016/
j.cattod.2018.04.061.
[23] M.G. Manas, L.S. Sharninghausen, E. Lin, R.H. Crabtree, Iridium catalyzed
reversible dehydrogenation-Hydrogenation of quinoline derivatives under
mild conditions, J. Organomet. Chem. 792 (2015) 184e189.
[
24] L. Zhang, X. Wang, Y. Xue, X. Zeng, H. Chen, R. Li, S. Wang, Cooperation be-
tween the surface hydroxyl groups of Ru-SiO @mSiO and water for good
catalytic performance for hydrogenation of quinoline, Catal. Sci. Technol. 4
2014) 1939e1948.
2
2
(
References
[25] Z.J. Yao, N. Lin, X.C. Qiao, J.W. Zhu, W. Deng, Cyclometalated half-sandwich
iridium complex for catalytic hydrogenation of imines and quinolines, Or-
ganometallics 37 (2018) 3883e3892.
[26] X. Wang, W. Chen, L. Zhang, T. Yao, W. Liu, Y. Lin, H. Ju, J. Dong, L. Zheng,
W. Yan, X. Zheng, Z. Li, X. Wang, J. Yang, D. He, Y. Wang, Z. Deng, Y. Wu, Y. Li,
Uncoordinated amine groups of metal-organic frameworks to anchor single
Ru sites as chemoselective catalysts towards the hydrogenation of quinoline,
J. Am. Chem. Soc. 139 (2017) 9419e9422.
[27] M. Campanati, M. Casagrande, I. Fagiolino, M. Lenarda, L. Storaro,
M. Battagliarin, A. Vaccari, Mild hydrogenation of quinoline: 2. A novel Rh-
containing pillared layered clay catalyst, J. Mol. Catal. A 184 (2002) 267e272.
[28] C. Chaudhari, H. Imatome, Y. Nishida, Y. Sato, K. Nagaoka, Recyclable Rh-PVP
nanoparticles catalyzed hydrogenation of benzoic acid derivatives and quin-
olines under solvent-free conditions, Catal. Commun. 126 (2019) 55e60.
[29] X. Yu, R. Nie, H. Zhang, X. Lu, D. Zhou, Q. Xia, Ordered mesoporous N-doped
carbon supported Ru for selective adsorption and hydrogenation of quinoline,
[
[
[
1] R. Kuwano, R. Ikeda, K. Hirasada, Catalytic asymmetric hydrogenation of
quinoline carbocycles: unusual chemoselectivity in the hydrogenation of
quinolines, Chem. Commun. 51 (2015) 7558e7561.
2] J.M. Campelo, D. Luna, R. Luque, J.M. Marinas, A.A. Romero, Sustainable
preparation of supported metal nanoparticles and their applications in
catalysis, ChemSusChem 2 (2009) 18e45.
3] M. Fang, R.A. S aꢀ nchez-Delgado, Ruthenium nanoparticles supported on
magnesium oxide: a versatile and recyclable dual-site catalyst for hydroge-
nation of mono- and poly-cyclic arenes, N-heteroaromatics, and S-hetero-
aromatics, J. Catal. 311 (2014) 357e368.
[
[
4] R. He, P. Cui, D. Pi, Y. Sun, H. Zhou, High efficient iron-catalyzed transfer hy-
drogenation of quinolines with Hantzsch ester as hydrogen source under mild
conditions, Tetrahedron Lett. 58 (2017) 3571e3573.
3 4
5] Y. Gong, P. Zhang, X. Xu, Y. Li, H. Li, Y. Wang, A novel catalyst pd@ompg-C N

10
H. Zhang et al. / Journal of Alloys and Compounds 834 (2020) 155203
Microporous Mesoporous Mater. 256 (2017) 10e17.
30] F. Zhang, C. Ma, S. Chen, J. Zhang, Z. Li, X.M. Zhang, N-doped hierarchical
particles alloying on the performances of Pt-Ru/CNT catalysts for selective
hydrogenation, J. Catal. 278 (2011) 59e70.
[42] Z. Yang, W. Chen, J. Zheng, Z. Yang, N. Zhang, C.J. Zhong, B.H. Chen, Efficient
low-temperature hydrogenation of acetone on bimetallic Pt-Ru/C catalyst,
J. Catal. 363 (2018) 52e62.
[
[
[
[
[
[
porous carbon anchored tiny Pd NPs: a mild and efficient quinolines selective
hydrogenation catalyst, Mol. Catal. 452 (2018) 145e153.
31] M. Niu, Y. Wang, W. Li, J. Jiang, Z. Jin, Thermoregulated poly (ethylene glycol)
biphasic system with Pd nanoparticle catalysts for selective hydrogenation of
cinnamaldehyde, Chin. J. Catal. 34 (2013) 674e678.
[43] C. Wei, C. Liu, L. Gao, Y. Sun, Q. Liu, X. Zhang, J. Guo, MoS
decorated Ni(OH) nanorod array for active overall water splitting, J. Alloys
Compd. 796 (2019) 86e92.
[44] L. Zhu, H. Sun, J. Zheng, C. Yu, N. Zhang, Q. Shu, B.H. Chen, Combining Ru, Ni
and Ni(OH) active sites for improving catalytic performance in benzene hy-
2
nanosheets
2
32] K. Li, B. Hao, M. Xiao, Y. Kuang, H. Shang, J. Ma, Y. Liao, H. Mao, Encapsulated
metal catalyst for selective hydrogenation of quinoline under atmospheric
conditions, Appl. Surf. Sci. 478 (2019) 176e182.
2
33] Z. Vít, D. Gulkov ꢀa , L. Kalu ꢁz a, M. Zdra ꢁz il, Synergetic effects of Pt and Ru added
drogenation, Mater. Chem. Phys. 192 (2017) 8e16.
to Mo/Al
2
O
3
sulfide catalyst in simultaneous hydrodesulfurization of thio-
[45] W. Jiang, L. Shen, K. Wang, M. Xu, Z. Tian, Study on Ni-Ni(S)-Ni(P) multilayer
coating by friction-assisted jet electroplating on sintered NdFeB, J. Alloys
Compd. 787 (2019) 1089e1096.
[46] V.Y. Pereyma, O.V. Klimov, I.P. Prosvirin, E.Y. Gerasimov, S.A. Yashnik,
A.S. Noskov, Effect of thermal treatment on morphology and catalytic per-
formance of NiW/Al O catalysts prepared using citric acid as chelating agent,
2 3
Catal. Today 305 (2018) 162e179.
[47] Y. Sun, C. Li, A. Zhang, Preparation of Ni/CNTs catalyst with high reducibility
and their superior catalytic performance in benzene hydrogenation, Appl.
Catal., A 522 (2016) 180e187.
phene and hydrogenation of cyclohexene, J. Catal. 232 (2005) 447e455.
34] I. Sorribes, L. Liu, A. Dom eꢀ nech-Carb oꢀ , A. Corma, Nanolayered cobalt-
molybdenum sulfides as highly chemo- and regioselective catalysts for the
hydrogenation of quinoline derivatives, ACS Catal. 8 (2018) 4545e4557.
35] L. Zhu, S. Shan, V. Petkov, W. Hu, A. Kroner, J. Zheng, C. Yu, N. Zhang, Y. Li,
R. Luque, C.J. Zhong, H. Ye, Z. Yang, B.H. Chen, Ruthenium-nickel-nickel hy-
droxide nanoparticles for room temperature catalytic hydrogenation, J. Mater.
Chem. A 5 (2017) 7869e7875.
36] L. Zhu, Y. Jiang, J. Zheng, N. Zhang, C. Yu, Y. Li, C.W. Pao, J.L. Chen, C. Jin, J.F. Lee,
C.J. Zhong, B.H. Chen, Ultrafine nanoparticle-supported Ru-nanoclusters with
ultrahigh catalytic activity, Small 11 (2015) 4385e4393.
37] J. Chen, Z.H. Lu, W. Huang, Z. Kang, X. Chen, Galvanic replacement synthesis of
NiPt/graphene as highly efficient catalysts for hydrogen release from hydra-
zine and hydrazine borane, J. Alloys Compd. 695 (2017) 3036e3043.
38] L. Zhu, T. Zheng, C. Yu, J. Zheng, Z. Tang, N. Zhang, Q. Shu, B.H. Chen, Platinum-
nickel alloy nanoparticles supported on carbon for 3-pentanone hydrogena-
tion, Appl. Surf. Sci. 409 (2017) 29e34.
[
[
[
[
[
[
2
[48] Y. Chen, J. Chen, Selective hydrogenation of acetylene on SiO supported Ni-In
bimetallic catalysts: promotional effect of in, Appl. Surf. Sci. 387 (2016)
16e27.
[49] L.P.C. Silva, L.E. Terra, A.C.S.L.S. Coutinho, F.B. Passos, Sour water-gas shift
2
reaction over Pt/CeZrO catalysts, J. Catal. 341 (2016) 1e12.
[50] A.V. Nartova, A. Gharachorlou, A.V. Bukhtiyarov, R.I. Kvon, V.I. Bukhtiyarov,
New Pt/Alumina model catalysts for STM and in situ XPS studies, Appl. Surf.
Sci. 401 (2017) 341e347.
[51] X.T. Li, H. Lei, C. Yang, Q.B. Zhang, Electrochemical fabrication of ultra-low
loading Pt decorated porous nickel frameworks as efficient catalysts for
methanol electrooxidation in alkaline medium, J. Power Sources 396 (2018)
64e72.
[52] C. Wang, X. Han, P. Xu, J. Wang, Y. Du, X. Wang, W. Qin, T. Zhang, Controlled
synthesis of hierarchical nickel and morphology-dependent electromagnetic
properties, J. Phys. Chem. C 114 (2010) 3196e3203.
39] Y. Huang, Y. Ma, Y. Cheng, L. Wang, X. Li, Supported nanometric platinum-
nickel catalysts for solvent-free hydrogenation of tetralin, Catal. Commun.
69 (2015) 55e58.
40] Y. Huang, Y. Ma, Y. Cheng, L. Wang, X. Li, Dimethyl terephthalate hydroge-
nation to dimethyl cyclohexanedicarboxylates over bimetallic catalysts on
carbon nanotubes, Ind. Eng. Chem. Res. 53 (2014) 4604e4613.
41] J. Teddy, A. Falqui, A. Corrias, D. Carta, P. Lecante, I. Gerber, P. Serp, Influence of