RSC Advances
Paper
However, the actual promotional role of S is still unclear.
Some studies suggest that the promotional effect of S arise from
the modication of the electronic density of the carbon atoms
induced by the presence of S atoms.54 While other reports
8 N. Parveen, M. O. Ansari, S. A. Ansari and M. H. Cho, J. Mater.
Chem. A, 2016, 4, 233.
9 D. Huang, Y. Luo, S. Li, B. Zhang, Y. Shen and M. Wang,
Nano Res., 2014, 7, 1054.
suggest that the promotional effect of S co-doping is due to the 10 Z. S. Wu, L. Chen, J. Liu, K. Parvez, H. Liang, J. Shu,
¨
higher amount of N incorporated in the nal catalyst during the
H. Sachdev, R. Graf, X. Feng and K. Mullen, Adv. Mater.,
synthesis of the catalysts. Herein, from the above analysis of
2014, 26, 1450.
cobalt catalysts, it is reasonable to suggest that both assump- 11 Y. Su, Y. Zhu, H. Jiang, J. Shen, X. Yang, W. Zou, J. Chen and
tions are possible in this system. On one hand, high amount of C. Li, Nanoscale, 2014, 6, 15080.
N in catalysts leads to an increase in the active sites, Co–Nx, so 12 Z. Liu, L. Ji, X. Dong, Z. Li, L. Fu and Q. Wang, RSC Adv.,
as to lead to high activity. On the other hand, the modication 2015, 5, 6259.
of the electronic density of S in carbon matrix is probably 13 Z. Liu, L. Ji, J. Liu, L. Fu and S. Zhao, J. Mol. Catal. A: Chem.,
benecial to stabilize the Co–Nx, which is easy to deactivate.
2014, 395, 315.
14 L. Fu, Y. Chen and Z. Liu, J. Mol. Catal. A: Chem., 2015, 408,
91.
15 S. Bag, B. Mondal, A. K. Das and C. R. Raj, Electrochim. Acta,
2015, 163, 16.
4. Conclusions
In conclusion, we have successfully synthesized carbon catalysts
with cobalt(II) meso-tetraphenyl porphyrin (CoTPP) as precursor
and sublimed sulfur as external sulfur species. The results
reveal that the sulfur element not only changes the physical
properties but also is doped into the catalysts, both into the
carbon matrix and the metal components. The Co–N–C–S0.2
exhibits highest catalytic activity than the other cobalt catalysts
for the selective oxidation of ethylbenzene which is attributed to
more Co–Nx active sites due to the adding of sulfur during the
calcination process of CoTPP. What's more, Co–N–C–S0.2 also
presents a preferential reusability in the heterogeneous catalytic
oxidation reaction causing by the stabilization effect of doping S
atoms in the carbon matrix.
16 A. Dhakshinamoorthy, A. Primo, P. Concepcion, M. Alvaro
and H. Garcia, Chem.–Eur. J., 2013, 19, 7547.
17 H. C. Chang, W. C. Min, H. P. Sung and I. W. Seong, Phys.
Chem. Chem. Phys., 2013, 15, 1802.
18 M. Latorre-Sanchez, A. Primo and H. Garcia, Angew. Chem.,
Int. Ed., 2013, 52, 11813.
19 J. Zhang, M. Zhang, G. Zhang and X. Wang, ACS Catal., 2012,
2, 940.
20 F. He, G. Chen, Y. Yu, Y. zhou, Y. Zheng and S. Hao, Chem.
Commun., 2015, 51, 425.
21 D. H. Shen, L. T. Ji, Z. G. Liu, W. B. Sheng and C. C. Guo, J.
Mol. Catal. A: Chem., 2013, 15, 379.
22 G. Li, G. Li, S. Ye and X. Gao, Adv. Energy Mater., 2012, 2,
1238.
Acknowledgements
23 G. Zhang, J. Zhang, M. Zhang and X. Wang, J. Mater. Chem.,
2012, 22, 8083.
The authors gratefully acknowledge the nancial support from
National Natural Science Foundation of China (No. 21103045,
1210040, 1103312), the Fundamental Research Funds for the
Central Universities, the State Key Laboratory of Heavy Oil in
China (No. SKCHOP201504) and the Key Laboratory of Miner-
alogy and Metallogeny in Chinese Academy of Sciences (No.
KLMM20150103).
24 S. Zhao, Y. Chen and Z. Liu, RSC Adv., 2015, 5, 33299.
¨
25 I. Herrmann, U. I. Kramm, S. Fiechter, V. Bruser, H. Kersten
and P. Bogdanoff, Plasma Processes Polym., 2010, 7, 515.
26 P. Ganesan, M. Prabu, J. Sanetuntikul and S. Shanmugam,
ACS Catal., 2015, 5, 3625.
27 Y. J. Gao, G. Hu, J. Zhong, Z. J. Shi, Y. S. Zhu, D. S. Su,
J. G. Wang, X. H. Bao and D. Ma, Angew. Chem., Int. Ed.,
2013, 52, 2109.
28 I. Herrmann, U. I. Kramm, J. Radnik, S. Fiechter and
P. Bogdanoff, J. Electrochem. Soc., 2009, 156, B1283.
References
1 A. Dhakshinamoorthy, M. Latorre-Sanchez, A. M. Asiri, 29 L. He, Z. C. Li and Z. J. Zhang, Nanotechnology, 2008, 19,
A. Primo and H. Garcia, Catal. Commun., 2015, 65, 10.
155606.
2 K. Ai, Y. Liu, C. Ruan, L. Lu and G. Lu, Adv. Mater., 2013, 25, 30 M. A. Vuurman, D. J. Stuens, A. Oskam, G. Deo and
998. I. E. Wachs, J. Chem. Soc., Faraday Trans., 1996, 92, 3259.
3 M. Seredych, K. Lszlu and T. J. Bandosz, ChemCatChem, 31 A. Boix, E. E. Miro, E. A. Lombardo, M. A. Banares,
2015, 7, 2924. R. Mariscal and J. L. G. Fierro, J. Catal., 2003, 217, 186.
4 S. Yang, L. Zhi, K. Tang, X. Feng, J. Maier and K. Mullen, Adv. 32 M. C. Biesinger, B. P. Payne, A. P. Grosvenor, L. W. M. Lau,
´
˜
ˆ
¨
Funct. Mater., 2012, 22, 3634.
A. R. Gerson and R. S. C. Smart, Appl. Surf. Sci., 2011, 257,
5 W. Yang, X. Yue, X. Liu, J. Zhai and J. Jia, Nanoscale, 2015, 7,
2717.
´ ´
33 C. Domınguez, F. J. Perez-Alonso, S. A. Al-Thabaiti,
11956.
´
6 W. H. Chiang, G. L. Chen, C. Y. Hsieh and S. C. Lo, RSC Adv.,
2015, 5, 97579.
S. N. Basahel, A. Y. Obaid, A. O. Alyoubi, J. L. Gomez de la
Fuente and S. Rojas, Electrochim. Acta, 2015, 157, 158.
7 G. Jo, J. Sanetuntikul and S. Shanmugam, RSC Adv., 2015, 5, 34 Y. Su, Y. Zhu, H. Jiang, J. Shen, X. Yang, W. Zou, J. Chen and
53637.
C. Li, Nanoscale, 2014, 6, 15080.
19490 | RSC Adv., 2016, 6, 19482–19491
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