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[Pt or Ptvoid@MOF (Y)] can be calculated with Equation (1):[19,24]
Synthesis of yolk–shell Ptvoid@MOF(Y) microspheres
In a typical procedure, as-synthesized Pt NPs solution (8 mL),
H2BDC (0.06 g), Ni(NO3)2·6H2O (0.1 g), and Zn(NO3)2·6H2O (0.1 g)
were dissolved in a mixture of DMF (16 mL) and ethylene glycol
(10 mL) with stirring for 1 h, and then the solution was aged at
1508C for 1.5 h. As-synthesized Pt NPs solution (8 mL, 0.6 mm) was
added dropwise with vigorous stirring for 2 h, and then the mixed
solution was further aged at 1508C for 4.5 h. Subsequently, the
precipitate was washed with DMF and alcohol several times and
then dried under vacuum at 608C overnight. The Pt content
(0.15 wt%) of the composites was measured by inductively cou-
pled plasma atomic emission spectroscopy (Varian 710-OES). Pt
NPs, yolk–shell Ni/Zn-MOF(Y), Pt/MOF(S), Pt@MOF(S), and yolk–
shell Ptin@MOF(Y) microspheres were fabricated (see Supporting In-
formation).
Eads ¼ Esurfaceþadsorbate ꢀ ðEsurface þ Eadsorbate
Þ
ð1Þ
where Esurface is the energy of the investigated surface, Eadsorbate the
energy of CAL or COL, and Esurface+adsorbate the energy of Pt or
Ptvoid@MOF(Y) with CAL or COL adsorbed.
Characterization
PXRD patterns were recorded by using a Rigaku XRD-6000 diffrac-
tometer with CuKa (l=1.542 ꢂ) radiation (40 kV, 30 mA). XPS was
performed with an ESCA LAB250 spectrometer (Thermo Electron)
by using AlKa radiation. The specific surface area was determined
with a Micrometitics Surface Area Analyzer (ASAP 2020). The mor-
phology of the materials was investigated by SEM (Zeiss SUPRA 55)
with an accelerating voltage of 20 kV, combined with EDS for ele-
mental analysis. TEM and HRTEM images were were obtained with
a JEOL JEM-2100 microscope at an accelerating voltage of 200 kV.
The X-ray absorption near-edge structure (XANES) was performed
at beamline 1W1B of the Beijing Synchrotron Radiation Facility
(BSRF), Institute of High Energy Physics (IHEP), Chinese Academy of
Sciences (CAS). The electron beam energy of the storage ring was
2.5 GeV with a stored current of 200 mA.
Catalytic selective hydrogenation of cinnamaldehyde (CAL)
to cinnamyl alcohol (COL)
Typically, CAL (0.5 mmol) and catalyst (0.1 mol% Pt NPs) were dis-
persed in isopropyl alcohol (5 mL). After flushing with N2, the auto-
clave was purged with H2 five times, and the final H2 pressure of
the autoclave was set at 1.0 MPa, and it was stirred at 508C. Then,
the catalysts were separated by centrifugation and washed with
ethanol for reuse, and the obtained reaction solution was filtered
through a filter membrane (0.22 mm) and then analyzed by GC-MS
(Bruker Scion TQ GC-MS/MS equipped with HP-5MS capillary
column).
Acknowledgements
This work was supported by the Natural Science Foundation of
China (21576006, 21606006, 51621003). We also thank the Na-
tional Supercomputing Center in Shenzhen for providing compu-
tational resources.
Model construction
The model of Pt was built by using the XRD data (space group
¯
FM3M, with a=b=g=908, a=b=c=3.9239 ꢂ). The supercell of
Pt is 5ꢁ5ꢁ2 in the a, b, and c directions. Then the (111) facet of Pt
was cleaved with a vacuum layer of 15 ꢂ, since the (111) facet has
been determined to be the exposed surface by HRTEM. Therefore,
the chemical formula of model Pt is Pt100. The model of Ni/Zn-MOF
Conflict of interest
The authors declare no conflict of interest.
¯
was also built from the XRD data (space group P1, with a=
10.2077, b=8.0135, c=6.3337 ꢂ and a=97.701, b=97.213, g=
108.7678). The supercell of Ni/Zn MOF is 2ꢁ2ꢁ1 in the a, b, and c
directions. Thus, the chemical formula of model Ni/Zn-MOF is
Ni6Zn6C64H72O56. The model of Ptvoid@MOF(Y) was constructed by
putting one layer of Pt atoms on Ni/Zn-MOF, and the vacuum layer
was 15 ꢂ.
Keywords: heterogeneous catalysis · hydrogenation · metal–
organic frameworks · nanoparticles · supported catalysts
[1] a) M. Behrens, F. Studt, I. Kasatkin, S. Kuehl, M. Haevecker, F. Abild-Ped-
ersen, S. Zander, F. Girgsdies, P. Kurr, B.-L. Kniep, M. Tovar, R. W. Fischer,
Chen, W. Li, L. Lin, M. Li, Y. Deng, X. Wang, B. Ge, C. Yang, S. Yao, J. Xie,
mannsdçrfer, M. Friedrich, N. Miyajima, R. Q. Albuquerque, S. Kummel,
Computational Method
All calculations are performed by employing the DFT plane-wave
pseudopotential method with the CASTEP code in the Accelrys ma-
terials studio version 6.1 software package.[19] The generalized gra-
dient approximation (GGA) Perdew–Burke–Ernzerhof (PBE) func-
tional and the ultrasoft pseudopotentials were used.[20,21] The
cutoff energy and Monkhorst–Pack mesh of k points were 380 eV
and (6ꢁ6ꢁ1), respectively. The Broyden–Fletcher–Goldfarb–
Shanno (BFGS) algorithm was applied in searching the potential-
energy surface during optimization.[22] The structure optimization
was based on the following three points: 1) an energy tolerance of
[3] a) M. Yang, S. Li, Y. Wang, J. A. Herron, Y. Xu, L. F. Allard, S. Lee, J. Huang,
1501; b) G.-H. Wang, J. Hilgert, F. H. Richter, F. Wang, H.-J. Bongard, B.
Spliethoff, C. Weidenthaler, F. Schueth, Nat. Mater. 2014, 13, 294–300;
1.0ꢁ10ꢀ5 eVatomꢀ1, 2) a maximum force tolerance of 0.03 eVꢂꢀ1
,
and 3) a maximum displacement tolerance of 1.0ꢁ10ꢀ3 ꢂ. A Fermi
smearing of 0.1 eV and Pulay mixing were employed to guarantee
fast convergence of the self-consistent field iterations.[23] The ad-
sorption energy Eads of the adsorbate (CAL or COL) on the surface
&
ChemSusChem 2019, 12, 1 – 8
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ÝÝ These are not the final page numbers!