Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
권호 표지

An Oxyfluorination Effect of Carbon Nanotubes Supports on Electrochemical Behaviors of Platinum Nanoparticle Electrodes

백금 나노입자전극의 전기화학적 거동에 대한 카본나노튜브 지지체의 산소-불소 처리효과

  • Kim, Seok (Advanced Materials Division, Korea Research Institute of Chemical Technology) ;
  • Lee, Jae-Rock (Advanced Materials Division, Korea Research Institute of Chemical Technology) ;
  • Park, Soo-Jin (Department of Chemistry, Inha University)
  • 김석 (한국화학연구원 화학소재연구단) ;
  • 이재락 (한국화학연구원 화학소재연구단) ;
  • 박수진 (인하대학교 화학과)
  • Received : 2007.09.28
  • Accepted : 2007.10.15
  • Published : 2008.02.28
Download PDF
⟨ Previous Next ⟩

Abstract

In the present study, the effect of oxyfluorination treatment on multi-walled nanotubes (MWNTs) supports was investigated by analyzing surface functional groups. The surface characteristics were determined by Fourier transformed-infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS). After the deposition of platinum nanoparticles on the above treated carbon supports, a crystalline size and a loading level had been investigated. Electrochemical properties of the treated MWNTs-supported Pt (Pt/MWNTs) catalysts were analyzed by current-voltage curve measurements. From the results of surface analysis, an oxygen and fluorine-containing functional group had been introduced to the surface of carbon supports. The oxygen and fluorine contents were the highest value at the treatment of 100 temperature. The Pt/100-MWNTs showed the smallest particle crystalline size of 3.5 nm and the highest loading level of 9.4% at the treatment of 100 temperature. However, the sample treated at the higher temperature showed the larger crystalline size and the lower loading level. This indicated that the crystalline size and the loading level could be controlled by changing the temperature of oxyfluorination treatment. Accordingly, an electrochemical activity was enhanced by increasing the temperature of treatment upto 100, and then decreased in the case of 200 and 300. The highest specific current density of 120 mA/mg had been obtained in the case of Pt/100-MWNTs.

본 연구에서는 multi-walled nanotubes(MWNTs)를 산소-불소 혼합가스로 처리하여, 표면 관능기를 분석하고, 그 처리효과를 조사하였다. 산소-불소 처리된 MWNTs의 표면특성은 FT-IR 그리고 XPS로 분석하였다. 처리된 탄소지지체에 백금 나노입자를 담지시킨 후, 입자 결정성크기와 담지함량을 조사하였다. 위 탄소지지체에 담지된 촉매의 전기화학적 특성은 전류-전압 곡선을 측정하여 분석하였다. 표면분석의 결과로부터, 산소 및 불소를 포함한 화학관능기가 탄소지지체에 도입된 사실을 알 수 있었다. 산소-불소 함량은 처리온도가 $100^{\circ}C$ 일때 최고값을 나타냈다. Pt/100-MWNTs 샘플의 경우, 3.5 nm의 최소의 결정성 크기를 보였고, 9.4%의 가장 높은 담지율을 나타냈다. 그러나, 이보다 높은 온도에서 처리된 샘플의 경우, 결정성 크기가 증가하였고, 담지율은 감소하였다. 이러한 결과를 통해, 결정성 크기와 담지율을 산소-불소 처리온도를 변화시켜 제어할 수 있었음을 제시하였다. 이와 연관되어, 촉매의 전기화학적 활성이 $100^{\circ}C$ 처리까지는 증가하다가, $200^{\circ}C$와 $300^{\circ}C$의 경우에는 감소하였다. Pt/100-MWNTs 샘플은 비교샘플 중에서 최고의 비전류밀도(specific current density)인 120 mA/mg 수치를 나타냈다.

Keywords

References

  1. Arico, A. S., Srinivasan, S. and Antonucci, V., "DMFCs: From Fundamental Aspects to Technology Development," Fuel Cells, 1(2), 133-161(2001). https://doi.org/10.1002/1615-6854(200107)1:2<133::AID-FUCE133>3.0.CO;2-5
  2. Chen, C. Y., Yang, P., Lee, Y. S. and Lin, K. F., "Fabrication of Electrocatalyst Layers for Direct Methanol Fuel Cells," J. Power Sources, 141(1), 24-29(2005). https://doi.org/10.1016/j.jpowsour.2004.09.011
  3. Joo, S. H., Choi, S. J., Oh, H., Kwak, J., Liu, Z., Terasaki, O. and Ryoo, R., "Ordered Nanoporous Arrays of Carbon Supporting High Dispersions of Platinum Nanoparticles," Nature, 412(6843), 169-172 (2001). https://doi.org/10.1038/35084046
  4. Gotz, M. and Wendt, H., "Binary and Ternary Anode Catalyst Formulations Including the Elements W, Sn and Mo for PEMFCs Operated on Methanol or Reformate Gas," Electrochim. Acta, 43(24), 3637-3644(1998). https://doi.org/10.1016/S0013-4686(98)00121-2
  5. Zhou, Z., Wang, S., Zhou, W., Wang, G., Jiang, L., Li, W., Song, S., Liu, J., Sun, G. and Xin, Q., "Novel Synthesis of Highly Active Pt/C Cathode Electrocatalyst for Direct Methanol Fuel Cell," Chem. Commun., 2003(3), 394-395(2003).
  6. Kwak, C., Park, T. J. and Suh, D. J., "Preferential Oxidation of Carbon Monoxide in Hydrogen-rich Gas over Platinum-cobaltalumina Aerogel Catalysts," Chem. Eng. Sci., 60(5), 1211-1217(2005). https://doi.org/10.1016/j.ces.2004.07.126
  7. Park, K. W. and Sung, Y. E., "Design of Nanostructured Electrocatalysts for Direct Methanol Fuel Cells", J. Ind. Eng. Chem., 12(2), 165-174(2006).
  8. Kim, D., Sauk, J., Kim, H., Lee, K. S. and Sung, J. Y., "Preparation of Composite Nafion/polyphenylene Oxide(PPO) with Hetropoly Acid(HPA) Membranes for Direct Methanol Fuel Cells," Korean Chem. Eng. Res., 44(2), 187-192(2006).
  9. Kim, S. and Park, S. J., "Effects of Chemically Modified Carbon Supports on Electrochemical Behaviors of Platinum Catalysts of Fuel Cells," J. Power Sources, 159(1), 42-45(2006). https://doi.org/10.1016/j.jpowsour.2006.04.041
  10. Kim, S. and Park, S. J., "Preparation and Electrochemical Behaviors of Platinum Nanoparticles Impregnated on Binary Carbon Supports as Catalyst Electrodes of Direct Methanol Fuel Cells," J. Solid State Electrochemistry, 11(6), 821-828(2007). https://doi.org/10.1007/s10008-006-0228-6
  11. Park, S. J., Jung, H. J. and Na, C. H., "Adsorption Properties of Fuel-Cell Electrode Produced from Activated Carbon Fibers in Three Phase Distribution," Polymer (Korea), 27(1), 46-51(2003).
  12. Kim, S. and Park, S. J., "Effect of Acid/Base Treatment to Carbon Blacks on Preparation of Carbon-Supported Platinum Nanoclusters," Electrochimica Acta, 52(9), 3013-3021(2007). https://doi.org/10.1016/j.electacta.2006.09.060
  13. Park, I. S., Park, K. W., Choi, J. H., Park, C. R. and Sung, Y. E., "Electrocatalytic Enhancement of Methanol Oxidation by Graphite Nanofibers with a High Loading of PtRu Alloy Nanoparticles," Carbon, 45(1), 28-33(2007). https://doi.org/10.1016/j.carbon.2006.08.011
  14. Yang, W., Yang, S. Guo, J., Sun, G. and Xin, Q., "Comparision of CNF and XC-72 Carbon Supported Palladium Electrocatalysts for Magnesium Air Fuel Cell," Carbon, 45(2), 397-401(2007). https://doi.org/10.1016/j.carbon.2006.09.003
  15. Frackowiak, E., Lota, G., Cacciaguerra, T. and Beguin, F., "Carbon Nanotubes with Pt-Ru Catalyst for Methanol Fuel Cell," Electrochemistry Comm., 8(1), 129-132(2006). https://doi.org/10.1016/j.elecom.2005.10.015
  16. Wang, H. J., Yu, H., Peng, F. and Lv, P., "Methanol Electrocatalytic Oxidation on Highly Dispersed Pt/Sulfonated-Carbon Nanotubes Catalysts, " Electrochemistry Comm., 8(3), 499-504(2006). https://doi.org/10.1016/j.elecom.2006.01.019
  17. Toit, F. J. and Sanderson, R. D., "Surface Fluorination of Polypropylene. 1. Characterization of Surface Properties," J. Fluor. Chem., 98(2), 107-114(1999). https://doi.org/10.1016/S0022-1139(99)00091-3
  18. Chtourou, H., Riedl, B. and Kokta, B.V., "ESCA and FTIR Study of Synthetic Pulp Fiber Modified by Fluorinated Gases and Corona Discharge," J. Colloid Interface Sci., 158(1), 96-104 (1993). https://doi.org/10.1006/jcis.1993.1233
  19. Nakajima, T., Gupta, V., Ohzawa, Y., Koh, M., Singh, R.N., Tressaud, A. and Durnad, E., "Electrochemical Behavior of Plasmafluorinated Graphite for Lithium Ion Batteries," J. Power Sources, 104(1), 108-114(2002). https://doi.org/10.1016/S0378-7753(01)00895-3
  20. Hruska Z. and Lepot, X., "Ageing of the Oxyfluorinated Polypropylene Surface: Ecolution of the Acid-Base Surface Characteristics with Time," J. Fluor. Chem., 105(1), 87-93(2000). https://doi.org/10.1016/S0022-1139(00)00292-X
  21. Gupta, V., Nakajima, T., Ohzawa, Y. and Iwata, H., "Electrochemical Characteristics and Structures of Surface-fluorinated Graphites with Different Particle Sizes for Lithium ion Secondary Batteries," J. Fluor. Chem., 112(2), 233-240(2001). https://doi.org/10.1016/S0022-1139(01)00517-6
  22. Kiplinger, C. L., Persico, D. F., Lagow, R. J. and Paul, D. R., "Gas Transport in Partilly Fluorinated Low-Density Polyethylene," J. Appl. Polym. Sci., 31(8), 2617-2626(1986). https://doi.org/10.1002/app.1986.070310818
  23. Nakajima, T., "Fluorine-containing Energy Conversion Materials," J. Fluor. Chem., 105(2), 229-238(2000). https://doi.org/10.1016/S0022-1139(99)00270-5
  24. Li, W., Liang, C., Qiu, J., Zhou, W., Han, H., Wei, Z., Sun, G. and Xin, Q. "Carbon nanotubes as Support for Cathode Catalyst of a Direct Methanol Fuel Cell,"Carbon, 40(5), 791-794(2002). https://doi.org/10.1016/S0008-6223(02)00039-8
  25. Kinoshita, K., "Carbon: Electrochemical and Physicochemical Properties," John Wiley, New York, 31-40(1988).