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RSC Advances
DOI: 10.1039/C6RA05967H
Journal Name
amount of broken pieces were also observed. Derived from 2.
both bright field and dark field TEM images (Fig. 5dꢀ5f), the
A. Cao, R. Luc and G. t. Veser, Physical Chemistry
Chemical Physics, 2010, 12, 13499ꢀ13510.
C. T. Campbell, S. C. Parker and D. E. Starr, Science,
3
.
average size of PtNPs of the CNR@Pt@CNP catalysts is 5.9 ±
.1 nm, which may explain the slightly decreased methane
conversion. The results suggest that PtNPs in the CNR@Pt
2
002, 298, 811ꢀ814.
2
4
.
C. Aydin, J. Lu, N. D. Browning and B. C. Gates, Angew.
Chem. Int. Ed. Engl., 2012, 51, 1ꢀ7.
catalysts sinter into large particles (Fig. 5aꢀ6c) and PtNPs in the 5.
CNR@Pt@CNP catalysts (Fig. 5dꢀ5f) are still small. Size
Y. Chen, H. Chen, L. Guo, Q. He, F. Chen, J. Zhou, J.
Feng and J. Shi, ACS Nano, 2010, 4, 529ꢀ539.
J. Lu, J. W. Elam and P. C. Stair, Acc. Chem. Res., 2013,
6
7
8
.
.
.
evolution of PtNPs also can be reflected from the XRD patterns
of the spent catalysts (Fig. S4). After 12ꢀhour reaction at 650
4
6, 1806ꢀ1815.
J. Wang, A.ꢀH. Lu, M. Li, W. Zhang, Y.ꢀS. Chen, D.ꢀX.
Tian and W.ꢀC. Li, ACS Nano, 2013, 7, 4902ꢀ4910.
G. Prieto, M. Shakeri, K. P. d. Jong and P. E. d. Jongh,
ACS Nano, 2014, 8, 2522ꢀ2531.
°
C, the XRD peak of metallic Pt phase at 39.5 ° is still very
weak for the CNR@Pt@CNP catalysts, similar to that of asꢀ
synthesized catalysts. While, the XRD peak of PtNPs for the
spent CNR@Pt is much stronger than that of the fresh CNR@Pt 9.
catalysts. The results also suggest the aggregated PtNPs in the
X. Liu, A. Wang, X. Yan, T. Zhang, C.ꢀY. Mou, D.ꢀS. Su
and J. Li, Chem. Mater., 2009, 21, 410ꢀ418.
G. Prieto, J. Zečević, H. Friedrich, K. P. d. Jong and P. E.
d. Jongh, Nat. Mater., 2013, 12, 34ꢀ39.
1
0.
CNR@Pt catalysts and preserved small PtNPs in the
CNR@Pt@CNP catalysts, which are consistent with the
observations in TEM images. The sum of the above
1
1.
J. A. Farmer and C. T. Campbell, Science, 2010, 329, 933ꢀ
9
36.
observations clearly indicate that the CeO
2
nanoparticle shell of 12.
X. Yan, X. Wang, Y. Tang, G. Ma, S. Zou, R. Li, X. Peng,
S. Dai and J. Fan, Chem. Mater., 2013, 25, 1556ꢀ1563.
H. S. Gandhi, G. W. Graham and R. W. McCabe, J.
Catal., 2003, 216, 433ꢀ442.
J. Lu, B. Fu, M. C. Kung, G. Xiao, J. W. Elam, H. H.
Kung and P. C. Stair, Science, 2012, 335, 1205ꢀ1208.
S. Damyanova, B. Pawelec, K. Arishtirova, M. V. M.
Huerta and J. L. G. Fierro, Appl. Catal., B, 2009, 89, 149ꢀ
159.
CNR@Pt@CNP functions as the stabilizer provides a physical
barrier to prevent PtNPs from sintering, and strengthens the
metalꢀsupport interface interaction and thermal stability of the
1
1
1
3.
4.
5.
2
CeO nanorod core. Thus, the remarkable thermal stability of
CNR@Pt@CNP catalysts can provide more accessible active
sites for catalytic reaction, leading to a stabilized activity at
high temperatures. The thermal stability and catalytic activity
of the CNR@Pt@CNP catalysts are comparable with or even 16.
M. Cargnello, N. L. Wieder, T. Montini, R. J. Gorte and P.
Fornasiero, J. Am. Chem. Soc., 2010, 132, 1402ꢀ1409.
X. Wang, D. Liu, S. Song and H. Zhang, J. Am. Chem.
Soc., 2013, 135, 15864ꢀ15872.
better than those of similar Pt/CeO core/shell catalysts for high
2
1
7, 20, 22, 41ꢀ43
17.
temperature methane oxidation.
1
1
2
2
8.
9.
0.
1.
S. H. Joo, J. Y. Park, C.ꢀK. Tsung, Y. Yamada, P. Yang
and G. A. Somorjai, Nat. Mater., 2009, 8, 126ꢀ131.
Y. Chen, H. Chen, L. Guo, Q. He, F. Chen, J. Zhou, J.
Feng and J. Shi, ACS Nano, 2010, 4, 529ꢀ539.
Conclusions
The sandwichꢀtype CNR@Pt@CNP catalysts, prepared via a
facile wet chemical synthetic route, exhibited a high activity
and stability for the methane oxidation at high temperatures.
The high activity and stability of the CNR@Pt@CNP can be
S. Song, X. Wang and H. Zhang, NPG Asia Materials,
2
015, 7, e179.
G. Chen, F. Rosei and D. Ma, Nanoscale, 2015, 7, 5578ꢀ
591.
5
ascribed to their unique physical structure by providing a thin 22.
ceria nanoparticle shell to prevent PtNPs from sintering,
K. Yoon, Y. Yang, P. Lu, D. Wan, H.ꢀC. Peng, K. S.
Masias, P. T. Fanson, C. T. Campbell and Y. Xia, Angew.
Chem. Int. Ed. Engl., 2012, 51, 9543ꢀ9546.
strengthen the thermal stability of the core of CeO nanorods
2
2
2
2
2
3.
4.
5.
6.
K. An, Q. Zhang, S. Alayoglu, N. Musselwhite, J.ꢀY. Shin
and G. A. Somorjai, Nano Letters, 2014, 14, 4907ꢀ4912.
J. C. Park, J. U. Bang, J. Lee, C. H. Ko and H. Song, J.
Mater. Chem., 2009, 20, 1239ꢀ1246.
Y. Wang, J. Liu, P. Wang, C. J. Werth and T. J.
Strathmann, ACS Catal., 2014, 4, 3551ꢀ3559.
and enhance the PtꢀCeO interaction. Hence, the sandwichꢀtype
2
CNR@Pt@CNP catalysts with good activity and stability may
serve as potential catalysts for the catalytic processes at high
temperature, especially for those involving hydrocarbon
molecules.
J. Xu, Y.ꢀQ. Deng, X.ꢀM. Zhang, Y. Luo, W. Mao, X.ꢀJ.
Yang, L. Ouyang, P. Tian and Y.ꢀF. Han, ACS Catal.,
2
014, 4, 4106ꢀ4115.
Acknowledgements
2
7.
E. Aneggi, D. Wiater, C. d. Leitenburg, J. Llorca and A.
Trovarelli, ACS Catal., 2014, 4, 172ꢀ181.
We acknowledge the financial support from a NSFC Grant
2
1401148, the Ministry of Science and Technology of China 28.
J. Li, Z. Zhang, Z. Tian, X. Zhou, Z. Zheng, Y. Ma and Y.
Qu, J. Mater. Chem. A, 2014, 2, 16459ꢀ16466.
S. Zhang, J. Li, W. Gao and Y. Qu, Nanoscale 2015, 7,
through a 973ꢀprogram under Grant 2012CB619401 and the
Fundamental Research Funds for the Central Universities.
Technical supports for TEM experiments from State Key
Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong
University, is also acknowledged.
2
3
3
9.
0.
1.
3
016ꢀ3021.
W. Tang, Z. Hu, M. Wang, G. D. Stucky, H. Metiu and E.
W. McFarland, J. Catal., 2010, 273, 125ꢀ137.
A. P. Ferreira, D. Zanchet, J. C. S. Araújo, J. W. C.
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| J. Name., 2012, 00, 1ꢀ3
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