Catalysis Science & Technology
Paper
property of Au NPs to favor CAL adsorption and activation.
Also, the significantly larger Au sizes (11.6 6.5 nm) of the
Au-Citr/SiO2 sample would mean more or less Citr redistribu-
tion on these enlarged Au particles, which offered more open
Au surface and possibly more specific sites in favor of CAL
activation. All these factors would contribute to maintain a
balanced activation of both H2 and CAL, making the catalytic
sites in this Au-Citr/SiO2 specific and much more active for
CAL hydrogenation.
7 K. Y. Lee, Y. W. Lee, J. Lee and S. W. Han, Colloids Surf., A,
2010, 372, 146–150.
8 H. Tsunoyama, N. Ichikuni, H. Sakurai and T. Tsukuda,
J. Am. Chem. Soc., 2009, 131, 7086–7093.
9 A. Quintanilla, V. C. L. Butselaar-Orthlieb, C. Kwakernaak,
W. G. Sloof, M. T. Kreutzer and F. Kapteijn, J. Catal., 2010,
271, 104–114.
10 J. A. Lopez-Sanchez, N. Dimitratos, C. Hammond, G. L. Brett,
L. Kesavan, S. White, P. Miedziak, R. Tiruvalam, R. L. Jenkins,
A. F. Carley, D. Knight, C. J. Kiely and G. J. Hutchings, Nat.
Chem., 2011, 3, 551–556.
11 R. Y. Zhong, Thesis for Master Degree in Chemistry, Tsingua
University, 2012.
12 Y. Feng, S. Xing, J. Xu, H. Wang, J. W. Lim and H. Chen,
Dalton Trans., 2010, 39, 349–351.
13 X. Xia, M. Yang, Y. Wang, Y. Zheng, Q. Li, J. Chen and
Y. Xia, ACS Nano, 2012, 6, 512–522.
14 A. N. Shipway, M. Lahav, R. Gabai and I. Willner, Langmuir,
2000, 16, 8789–8795.
15 P. Pimpang and S. Choopun, Chiang Mai J. Sci., 2011,
38, 31–38.
16 N. Kristian, Y. Yan and X. Wang, Chem. Commun., 2008,
353–355.
17 K. Q. Sun, S. W. Luo, N. Xu and B. Q. Xu, Catal. Lett., 2008,
124, 238–242.
18 H. Shi, N. Xu, D. Zhao and B. Q. Xu, Catal. Commun., 2008,
9, 1949–1954.
4. Conclusions
This work demonstrates that citrate anion was a weak stabi-
lizer for Au NPs in the colloidal solution and can be easily
substituted with PVP, PVA and CTAB, respectively. The substi-
tution with the polymer stabilizers (PVP and PVA) showed not
only no impact on the Au size in the colloidal solution but
also “prevented” possible growth of the Au NPs during their
immobilization on the non-interacting SiO2 support. CTAB
appeared to be a relatively weaker stabilizer; its exchange with
Au-Citr was accompanied by significant enlargement of the
Au NPs. These stabilizer substitutions produced significant
impact on the catalysis of Au NPs for the hydrogenation of
both p-CNB and CAL, due to steric hindrance or electronic
modification, or both of the two effects imposed upon by the
different stabilizers. The distinctively varied Au activity of the
Au-Citr/SiO2 catalyst in the two hydrogenation reactions
would imply that the active Au sites for CAL activation were
different from those for p-CNB activation.
19 D. P. He, H. Shi, Y. Wu and B. Q. Xu, Green Chem., 2007,
9, 849–851.
20 K. Q. Sun, Y. C. Hong, G. R. Zhang and B. Q. Xu, ACS Catal.,
2011, 1, 1336–1346.
Acknowledgements
21 X. W. Yang, G. R. Zhang, Y. X. Li and B. Q. Xu, Acta Phys.-
Chim. Sin., 2009, 25, 2565–2569.
22 G. Kawamura, Y. Yang and M. Nogami, J. Phys. Chem. C,
2008, 112, 10632–10636.
23 Y. Yang, S. Matsubara, M. Nogami, J. Shi and W. Huang,
Nanotechnology, 2006, 17, 2821–2827.
24 P. Serna, P. Concepcion and A. Corma, J. Catal., 2009, 265,
19–25.
25 C. Milone, R. Ingoglia, L. Schipilliti, C. Crisafulli, G. Neri
and S. Galvagno, J. Catal., 2005, 236, 80–90.
26 X. Yang, A. Wang, X. Wang, T. Zhang, K. Han and J. Li,
J. Phys. Chem. C, 2009, 113, 20918–20926.
27 G. Kang, Z. Chen, Z. Li and X. He, J. Chem. Phys., 2009,
130, 034701.
28 M. Boronat, F. Illas and A. Corma, J. Phys. Chem. A, 2009,
113, 3750–3757.
29 A. Gole and C. J. Murphy, Chem. Mater., 2005, 17, 1325–1330.
This work was financially supported by the National Natural
Science Foundation of China (grants: 21033004 & 21221062)
and the Program for Basic Research of the Ministry of Science
and Technology of China (grant: 2013CB933103).
References
1 T. Takei, T. Akita, I. Nakamura, T. Fujitani, M. Okumura,
K. Okazaki, J. H. Huang, T. Ishida and M. Haruta, Adv.
Catal., 2012, 55, 1–126.
2 A. A. Herzing, C. J. Kiely, A. F. Carley, P. Landon and
G. J. Hutchings, Science, 2008, 321, 1311–1335.
3 N. Semagina and L. Kiwi-Minsker, Catal. Rev., 2009, 51, 147–217.
4 Y. Sun and Y. Xia, Science, 2002, 298, 2176–2179.
5 G. R. Zhang and B. Q. Xu, Nanoscale, 2010, 2, 2798–2804.
6 A. Villa, D. Wang, D. S. Su and L. Prati, ChemCatChem, 2009,
1, 510–514.
This journal is © The Royal Society of Chemistry 2013
Catal. Sci. Technol., 2013, 3, 3013–3019 | 3019