10.1002/cctc.201700111
ChemCatChem
COMMUNICATION
Cu+ species by the unique core-shell structure of Cu@CeO2
catalysts. We found out that the surface area of Cu cores, i.e. the
interface area between Cu and CeO2 species (SXCu),
demonstrates a positive correlation with the total surface areas of
Cu0 and Cu+ species (Table 1), indicating a uniform distribution of
the two active sites on the interface between Cu core and CeO2
shell. Thus, according to the Cu+ species formed by the Cu-CeOx
species, both of the Cu0 and Cu+ would generate on the interface
between the Cu core and CeO2 shell. This distribution manner
(Scheme 1c) can achieve a close relative position of the two
active sites, which would effectively enhance the synergetic effect
on the catalysis for MA hydrogenation.
was tabled, crushed and sieved to 40-60 mesh for reaction. Additionally,
the contrastive Cu/CeO2-IM sample was prepared by a typical incipient-
wetness impregnation method. The support CeO2 nanoparticles were
synthesized through procedures as the same as above without the addition
of copper nitrate, but only calcined at 300oC for 2 h. After impregnation,
the obtained solid was calcined again at 400 oC for 2 h.
The materials information, detailed procedures of characterizations
(such as TEM, XRD, XPS, and N2O-CO titration), catalytic activity
evaluation and products analysis were described in the Supporting
Information.
Acknowledgements
This research was supported by the National Natural Science
Foundation of China (21325626, 91434127) and the Program of
Introducing Talents of Discipline to Universities (B06006).
Keywords: Copper-based catalyst • core-shell structure •
ethanol • heterogeneous catalysis • hydrogenation
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Figure 5. Effects of a) Cu+ active sites and b) Cu0 active sites of Cu@CeO2
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Experimental Section
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The Cu@CeO2 catalyst was fabricated by a facile and efficient sol-gel
method. Briefly, copper nitrate and cerium nitrate with calculated
proportions were dissolved with 25 mL deionized water. Meanwhile,
dissolve a certain amount of citric acid (the mole ratio of citric acid / (copper
nitrate + cerium nitrate) is 1:1) into another 25 mL deionized water. These
two solutions were blended together and kept stirring for 1 h at room
temperature. Then, the mixture was heated to 65 oC for 1 h under vacuum
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100 C for 10 h, the sample was calcined in static air at 300oC for 2 h to
decompose the citric acid and then heated to 400 oC for 2 h. The
temperature ramp for calcination was 1 oC/min. Then the resulting solid
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