Z.-X. Li, et al.
Molecular Catalysis 480 (2020) 110651
Fig. 1. XRD patterns of the samples.
FM in isopropanol (IP) or to THFM in water and LAH to VL in water.
. Experimental
2.4. Catalytic reaction
A substrate (50 μL), a Ni
x
Zn/NC
y
(50 mg), and a solvent (10 mL) are
2
added to an 60 mL magnetically stirred autoclave. After replacing air in
the autoclave with N , a certain amount of hydrogen was filled into the
2
2.1. Materials
autoclave. Then, the autoclave was heated to a required temperature
and maintained at the temperature for an indicated period of time at
Furfural (99.0%), LA (99.0%), FM (99.0%), THFM (99.0%), VL
1
50 rpm.
(
(
99.0%), IP, hexane, ethanol, methanol, butanol, 2-methylimidazole, Ni
NO
3
)
2
•6H
2
O, and Zn(NO
3
)
2
•6H
2
O
were purchased from Aladdin
and
Industrial Inc., Shanghai, China and used without purification. N
2
3
. Results and discussion
H used are highly pure gases.
2
3.1. Catalyst characterization
2.2. Catalyst preparation
The diffraction peaks shown in Fig. 1 at 31.7°, 34.4°, 36.3°, 47.5°,
6.6°, 62.8°, 66.4°, 67.9°, and 69.7° are attributed to representative
2
.2.1. Preparation of ZIFW-8
5
Typically, 10.4 g Zn(NO
3
)
2
•6H O and 7.4 g 2-methylimidazole are
2
diffractions of planes (100), (002), (101), (102), (110), (103), (200),
dissolved in 65 mL and 50 mL water, respectively [38,41]. Then, the
former is quickly poured into the latter one with rapidly appearing
white precipitates. After being stirred at 30 °C for 12 h, ZIFW-8 is col-
lected by centrifugation, washed with water and ethanol sequentially,
and dried at 80 °C in vacuum for 12 h.
(
112), and (201) of crystalline ZnO, respectively (PDF#36-1451), while
the characteristic diffraction peaks located at 42.7°, 49.7°, 73.1°, and
8
8.5° can be attributed to representative diffraction of planes (111),
(
200), (220), and (311) of Ni
3
ZnC0.7 (PDF#28-0713), respectively. The
diffraction peaks of Ni
3
ZnC0.7 were significantly enhanced with in-
creasing Ni loading. Transmission electron microscopic images (Fig. S1)
2
.2.2. Preparation of Ni
Typically, 2.47 g Ni(NO
Then, 5.00 g ZIFW-8 is dispersed in the Ni(NO
tion followed by agitation at 30 °C for 12 h to obtain Ni0.09/ZIFW-8 by
x
/ZIFW-8
of Ni
x
Zn/NC600 also show that the number of Ni ZnC0.7 particles in-
3
3
)
2
•6H
2
O is dissolved in 70 mL ethanol.
creased significantly with increasing Ni content. As observed from TG
3
)
2
•6H O/ethanol solu-
2
curves, Ni0.09/ZIFW-8 rapidly decomposed with raising the temperature
to 320 °C under flow N
2
(Fig. S2). Hence, Ni0.09Zn/NC were prepared
y
subsequent filtration, washing, and drying. Other Ni /ZIFW-8 species
x
at 400, 500, 600, and 700 °C. The diffraction peaks of ZnO and
Ni ZnC0.7 increased with raising CT, indicating that the crystal sizes of
ZnO and Ni
were prepared in the same way, where x represents the molar ratio of Ni
to Zn (x = 0.01, 0.05, 0.09, and 0.13).
3
3
ZnC0.7 tend to increase at higher temperatures (Fig. 1).
Ni, Zn, N, C, O, NiO, and ZnO were confirmed to exist in Ni0.09Zn/
2
.2.3. Preparation of Ni
Typically, Ni0.09Zn/NC600 is prepared by calcining Ni0.09/ZIFW-8
under N at 600 °C for 5 h. Other Ni Zn/NC species were prepared in
the same way, where x represents the molar ratio of Ni to Zn (x = 0.01,
.05, 0.09, and 0.13) and y represents the calcination temperature (CT)
of Ni /ZIFW-8 (y = 400, 500, 600, and 700 °C).
x
Zn/NC
y
NC
(Table S1, Figs. 2 and S3). Peaks for Ni 2p1/2 at 870.1 eV and Ni
6
00
2p3/2 at 852.8 eV correspond to metallic Ni and peaks of Ni 2p1/2 at
871.6 and 873.0 eV and Ni 2p3/2 at 854.8, 855.8, 857.3, 858.9, and
861.2 eV could be attributed to NiO [42–44], while the peaks of Ni 2p3/
2 at 853.6 eV suggest the existence of the carbide phase in the carbon
composite [45,46] (Fig. 2). The peak at 1021.8 eV was also identified
corresponding to ZnO (Fig. S3) [47]. Ni0.09Zn/NC600 contains pyridine
2
x
y
0
x
2.2.4. Preparation of Zn/NC and Ni/NC
Zn/NC and Ni/NC were prepared by calcining ZIFW-8 and Ni-ZIFW,
respectively, under N at 600 °C for 5 h.
2
2.3. Characterization techniques
Each catalyst structure was characterized with a Hitachi S-3700 N
scanning electron microscope combined with an energy dispersive
spectrometer (EDS), a JEM-2100 microscope transmission electron
microscope, an ESCALAB 250 X-ray photoelectron spectroscope, a
Bruker Advance X-ray diffraction (XRD), a Nicolet Magna IR-560
Fourier transform infrared spectrometer, a TP-5000 multi-function NH
3
temperature-programmed desorption (NH -TPD) instrument, a TA SDT-
3
Q600 thermo gravimetric (TG) analyzer, and a laser ablation in-
ductively coupled plasma mass spectrometer (LA/ICPMS).
Fig. 2. X-ray photoelectron spectrum of Ni0.09Zn/NC600
.
2