ChemCatChem
10.1002/cctc.201601196
FULL PAPER
procedures. Benzene was degassed and stored under argon prior to use.
All of the other chemicals were purchased from commercial sources and
used without further purification. NMR spectra were recorded on a Varian
VNMR spectrometer (300 MHz).
The sample was investigated using the long scan, Ru 3d, Ru 3p3/2, Pt 4f,
O 1s and C 1s scan regions. The spectra were collected using an InSb
(111) double crystal monochromator at fixed photon energies of 1840
and 3000 eV. The hemispherical electron analyser (PHOIBOS HSA3500
1
50 R6) was set at a pass energy of 30 eV, and the energy step was 0.1
eV, with an acquisition time of 100 ms/point. The overall resolution was
around 0.3 eV. The base pressure used inside the chamber was around
GC and GC-MS. GC analyses were run with an Agilent Technologies GC
System 6820 with a FID detector and a DB-17 column (T injector =
-
9
1
.0 × 10 mbar. The monochromator photon energy calibration was done
2
2
50 °C; P = 103 kPa; T program = 10 min at 40 °C, 10 °C/min until
50 °C, then 10 min at 250 °C). GC-MS analyses were run with a
at the Si K edge (1839 eV). An additional calibration of the analyser’s
energy was performed using a standard Au foil (Au 4f7/2 peak at 83.8 eV).
We also considered the C 1s peak value of 284.5 eV as reference to
verify possible charging effects. The XPS measurements were obtained
at a 45° take off angle at room temperature.
Shimadzu QP50 with a Rtx-5MS column; T injector = 250 °C; P = 103
kPa; T program = 10 min at 40 °C, 10 °C/min until 250 °C, then 10 min at
2
50 °C; EI = 70 eV).
Preparation of Ru@Pt NPs. A standard reaction: a Fischer-Porter bottle
was loaded in the dry-box with the precursor [Ru(COD)(2-methylallyl)
64.5 mg, 0.2 mmol) and 6 mL BMI.PF . The system was stirred under
XRD. The XRD patterns were recorded for a 2θ range of 20° to 90° with
a 0.05° step size and measurement time of 1 s per step with Cu Kα
radiation (λ = 1.54 Å) and monochromator of graphite. Data processing
was performed by the Rietveld method using FullProf software. The
instrumental resolution function (IRF) of the diffractometer was obtained
2
]
(
6
vacuum for 20 min and heated until 75 °C. Then, 5 bar hydrogen was
added to the system and kept reacting for 18 h at 75 °C. The obtained
black suspension was evacuated to remove the volatiles. Then, to the
6
from the LaB standard.
2 3
formed Ru nanoparticles, a solution of [Pt (dba) ] (110 mg, 0.1 mmol) in
1
0 mL acetonitrile was added. All volatile compounds were removed
under reduced pressure at 75 °C and 4 bar of hydrogen were added.
After 24 h the black solution was washed with benzene (3 x 20 mL),
ethanol (3 x 10 mL) and pentane (3 x 30 mL). Again, the system was
evacuated to remove all volatile compounds. The formed nanoparticles
were stored under argon at -20 °C. The nanoparticles were analysed by
transmission electron microscopy (TEM), scanning transmission electron
microscopy (STEM), energy-dispersive X-ray spectroscopy (EDS), X-ray
photoelectron spectroscopy (XPS) and electron and X-ray diffraction
Acknowledgements
The authors thank NULAM/DIMAT-INMETRO and LNLS for the
use of the TEM microscopes and the beam-line, respectively. A.
W. acknowledges the DAAD for a scholarship. M. H. G. P. is
grateful for financial support by the DFG (Heisenberg-Program).
(
XRD). For XRD analysis the NPs were isolated by centrifugation with the
addition of THF (10 mL) and washed with DCM (10 x 10 mL), ethanol (10
x 10 mL) and pentane (3 x 10 mL) and dried under reduced pressure.
Keywords: nanoparticles • ionic liquids • hydrogenation • non-
equilibrium • arenes
Hydrogenation of Benzene. As a general procedure, a solution of
benzene (4 mL, benzene/catalyst = 670) with a co-solvent n-heptane (2
[
1]
L. Foppa, J. Dupont, Chem. Soc. Rev. 2015, 44, 1886-1897.
J. A. Don, J. J. F. Scholten, Faraday Discuss. 1981, 72, 145.
M. Boudart, Adv. Catal. 1969, 20, 153-166.
mL) was added to
appropriate amount of catalyst (67 µmol of metal NPs) dissolved in
BMI.PF (1 mL). The reactor was pressurised with 6 bar of H at 60 °C.
a Fischer–Porter reactor that contained the
[2]
[
[
3]
4]
G. A. Somorjai, J. Carrazza, Ind. Eng. Chem. Fund. 1986, 25, 63-
6
2
6
9.
Sample was taken from the reaction mixture every 10 min. After the
desired reaction time, the reactor was cooled to room temperature and
depressurised. GC and GC-MS analysis (Figures S8-S10) of the samples
were used to determine conversions and selectivities.
[
5]
K. M. Bratlie, H. Lee, K. Komvopoulos, P. Yang, G. A. Somorjai,
Nano Lett. 2007, 7, 3097-3101.
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, Small 2015, 11,
[6]
4
385-4393.
[
7]
M. M. Stalzer, C. P. Nicholas, A. Bhattacharyya, A. Motta, M.
Delferro, T. J. Marks, Angew. Chem. Int. Ed. 2016, 55, 5263-5267.
P. J. Dyson, Dalton Trans. 2003, 2964-2974.
RBS measurements were carried out in a 3 MV Tandetron accelerator
+
[8]
using a He ion beam of 1.5 MeV at IF/UFRGS. The Si surface-barrier
[
[
9]
H. Nagahara, M. Ono, Y. Fukuoka, Stud. Surf. Sci. Catal. 1995, 92,
detector was positioned at a scattering angle of 165°.
3
75-378.
10]
K. Yamashita, H. Obana, I. Katsuta, Vol. EP552809A1, Asahi
Kasei Kogyo K. K., 1993, p. 31 pp.
TEM and STEM. TEM analysis was performed using a JEOL JEM 1200
ExII operating at 80 kV. TEM samples were prepared by dropping the
acetone-diluted solution of the isolated Ru@Pt nanoparticles onto a
copper TEM grid. Ruthenium and Platinum content were determined by
EDS using a NORAM Pioneer spectrometer with a beam energy of 200
kV. STEM and high-resolution TEM (HRTEM) were performed using a
XFEG Cs-corrected FEI Titan 80/300 microscope at INMETRO operated
at 80 and 300 kV. High Z-contrast images were acquired through STEM
using a high angle annular dark field detector (HAADF) and a semi-
convergence angle of 27.4 mrad. Spatial-correlated EDS profile
experiments were carried out using K and L lines from Ru and Pt. The
typical lateral resolution was greater than 0.1 nm.
[
[
11]
12]
C. Morin, D. Simon, P. Sautet, Surf. Sci. 2006, 600, 1339-1350.
M. Saeys, M. F. Reyniers, M. Neurock, G. B. Marin, J Phys Chem
B 2005, 109, 2064-2073.
H. Imamura, K. Nishimura, K. Sumioki, M. Fujimoto, Y. Sakata,
Chem. Lett. 2001, 450-451.
[13]
14]
[15]
[
X. Su, K. Kung, J. Lahtinen, R. Y. Shen, G. A. Somorjai, Catal. Lett.
1
998, 54, 9-15.
B. E. Koel, D. A. Blank, E. A. Carter, J. Mol. Catal. A: Chem. 1998,
131, 39-53.
F. Schwab, M. Lucas, P. Claus, Angew. Chem. Int. Ed. 2011, 50,
[
[
16]
17]
1
0453-10456.
E. T. Silveira, A. P. Umpierre, L. M. Rossi, G. Machado, J. Morais,
G. V. Soares, I. L. R. Baumvol, S. R. Teixeira, P. F. P. Fichtner, J.
Dupont, Chem. Eur. J. 2004, 10, 3734-3740.
S. Alayoglu, P. Zavalij, B. Eichhorn, Q. Wang, A. I. Frenkel, P.
Chupas, ACS Nano 2009, 3, 3127-3137.
[
[
18]
19]
XPS. For the XPS measurements, the powder of the Ru@Pt
S. Alayoglu, A. U. Nilekar, M. Mavrikakis, B. Eichhorn, Nature
Mater. 2008, 7, 333-338.
nanoparticles was spread out over the carbon tape and introduced into
[
6]
the analysis chamber at the D04A-SXS beam-line endstation at LNLS.
This article is protected by copyright. All rights reserved.