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Table 2 Effect of activation step on ethanol electrooxidation
Pdꢁ
1
ꢁ2
Pdꢁ1
ꢁ2
f b
I /I
Eop (V)
J
f
(mA mg
cm
)
E
f
(V)
J
b
(mA mg
cm
)
E
b
(V)
Activated Pd/PMo12/GNSs
Pd/PMo12/GNSs
ꢁ0.68
ꢁ0.53
31 668
2341
ꢁ0.275
ꢁ0.210
7722
836
ꢁ0.409
ꢁ0.300
4.1
2.8
Table 2 shows the effect of activation step on the perfor-
mance of the catalyst towards the catalytic electrooxidation of
ethanol. Comparison of the CVs indicates the excellent perfor-
mance of the activated Pd/PMo /GNSs catalyst.
3 S. M. Choi, M. H. Seo, H. J. Kim and W. B. Kim, Carbon, 2011,
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4 L. Gao, W. Yue, S. Tao and L. Fan, Langmuir, 2012, 29, 957–
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1
2
5
6
R. Kannan, A. Kim and D. Yoo, J. Appl. Electrochem., 2014, 44,
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A. Santasalo-Aarnio, Y. Kwon, E. Ahlberg, K. Kontturi,
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13, 466–469.
8
Conclusion
We have shown that the tri-component of Pd/PMo12/GNSs
nanohybrid can be used as an efficient electrocatalyst for
oxidation of ethanol. This material has been prepared using the
Keggin-type polyoxometalate phosphomolybdic acid (PMo ) as
7 J. L. Dongyao Wang, Z. Wu, J. Zhang, Y. Su, Z. Liu and C. Xu,
Int. J. Electrochem. Sci., 2009, 4, 1672–1678.
1
2
both a reducing and stabilising agent. A novel method for
activation of the catalyst has also been described and the elec-
trochemical investigations here within indicate that this acti-
vation process substantially enhances the electrocatalytic
8 S. C. Si-Wen Xie, Z.-Q. Liu and C.-W. Xu, Int. J. Electrochem.
Sci., 2011, 6, 882–888.
9 Z. Cui, P. J. Kulesza, C. M. Li, W. Xing and S. P. Jiang, Int. J.
Hydrogen Energy, 2011, 36, 8508–8517.
activity of the catalyst. Consequently, the as-prepared tri- 10 X.-M. Chen, Z.-J. Lin, T.-T. Jia, Z.-M. Cai, X.-L. Huang,
component nanohybrid catalyst showed a considerably higher
electrocatalytic activity towards ethanol oxidation. The superior
Y.-Q. Jiang, X. Chen and G.-N. Chen, Anal. Chim. Acta,
2009, 650, 54–58.
electrocatalytic performance is a synergic effect resulting prin- 11 R. N. Singh, A. Singh and Anintida, Carbon, 2009, 47, 271–
cipally from: (i) the superior electron mobility of GNSs and ionic
278.
conductivity of PMo12; (ii) the small size and high dispersion of 12 R. N. Singh and R. Awasthi, Catal. Sci. Technol., 2011, 1, 778–
PdNPs on the GNS support; (iii) a possible synergic and
783.
42
bifunctional effect between PdNPs and PMo12
;
and (iv) 13 N. Tian, Z.-Y. Zhou, N.-F. Yu, L.-Y. Wang and S.-G. Sun, J. Am.
formation of abundant Pd-OHads sites in the activation step.
Moreover, because of the higher ECSA, better tolerance towards 14 C. W. Xu, H. Wang, P. K. Shen and S. P. Jiang, Adv. Mater.,
poisoning carbonaceous species and improve onset potential, 2007, 19, 4256–4259.
the Pd/PMo /GNSs shows an enhanced catalytic activity 15 P. K. Shen and C. Xu, Electrochem. Commun., 2006, 8, 184–
Chem. Soc., 2010, 132, 7580–7581.
1
2
compared to Pd/PMo12/CNTs. In summary, the activated
188.
Pd/PMo12/GNSs nanohybrid showed highly promising features 16 H. Wang, C. Xu, F. Cheng and S. Jiang, Electrochem.
for development of Pd-based catalysts to be used in alkaline
direct ethanol fuel cells.
Commun., 2007, 9, 1212–1216.
17 S. Park and R. S. Ruoff, Nat. Nanotechnol., 2009, 4, 217–224.
18 S. Rajabzadeh, G. Ronagi, M. H. Arbab Zavar and N. Ashraf,
Electrochim. Acta, 2014, 135, 543–549.
Acknowledgements
19 A. Ahmadpour, A. Ayati, H. Rashidi and B. Tanhaei, Synth.
React. Inorg., Met.-Org., Nano-Met. Chem., 2012, 42, 209–230.
The authors would like to thank Mrs S. Rajabzade for her help
with the electrochemical measurements. TEM, HAADF-STEM 20 A. Ahmadpour, B. Tanhaei and A. Ayati, Curr. Nanosci., 2012,
measurements have been performed through part of the fund
8, 880–884.
of the Marie Curie Intra-European Fellowship 328985-COCO- 21 A. Ayati and A. Ahmadpour, Gold Bull., 2012, 45, 145–151.
POPS and ERC-Starting Grant 239931-NANOPUZZLE. Dr 22 A. Ayati, A. Ahmadpour, H. Rashidi and B. Tanhaei, Journal
Rodrigo Fern ´a ndez-Pacheco (LMA-UNIZAR) provided invalu-
of Nanostructure in Chemistry, 2011, 2, 15–22.
able advice and assistance with the electron microscopy data 23 S. G. Mitchell and J. M. de la Fuente, J. Mater. Chem., 2012,
collection.
22, 18091–18100.
2
2
4 Y. Wang and I. A. Weinstock, Chem. Soc. Rev., 2012, 41, 7479–
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