Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Preparations of SPE Electrocatalysts Modified with Polypyrrole and Its Application for PEMFC

폴리피롤로 개질된 SPE 전극촉매의 제조 및 PEMFC로의 응용

  • Kim, Jung-Hoon (Department of Chemical Engineering, Yonsei University) ;
  • Oh, Seung-Duck (Department of Chemical Engineering, Yonsei University) ;
  • Kim, Han-Sung (Hyosung Corporation R&D Center for Chemical Technology) ;
  • Park, Jong-Ho (SKC Central R&D Center) ;
  • Han, Jung-Woo (Hanwha Chemical Research & Development Center) ;
  • Lee, Kang Taek (Department of Chemical Engineering, Yonsei University) ;
  • Joe, Yung-Il (Department of Chemical Engineering, Yonsei University)
  • 김정훈 (연세대학교 화학공학과) ;
  • 오승덕 (연세대학교 화학공학과) ;
  • 김한성 ((주)효성 화학연구소) ;
  • 박종호 (SKC(주) 중앙연구소) ;
  • 한정우 (한화석유화학(주) 중앙연구소) ;
  • 이강택 (연세대학교 화학공학과) ;
  • 조영일 (연세대학교 화학공학과)
  • Received : 2003.10.14
  • Accepted : 2004.10.19
  • Published : 2005.02.28
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Abstract

In this study, a novel deposition method of Pt catalysts onto Nafion membranes modified with polypyrrole (PPy) has been proposed for PEMFC application. The PPy/Nafion composite membranes were fabricated by chemical polymerization of pyrrole using $FeCl_3$ and $Na_2S_2O_8$ as initiator. The proton conductivity and water uptake of the chemically prepared PPy/Nafion composites were investigated. The ionic conductivity and water uptake of PPy/Nafion composite membrane prepared with $Na_2S_2O_8$ were decreased with polymerization time of pyrrole. In the case of $FeCl_3$, the ionic conductivity was almost retained and the water uptake was decreased with polymerization time of pyrrole. When the Pt particle was deposited on PPy/Nafion composites membrane by chemical reduction of $H_2PtCl_6$, the Pt loading on Nafion membrane was enhanced by polypyrrole due to electronic conduction property. The performance evaluation with membrane electrode assembly composed of Pt/PPy/Nafion composite and diffusion electrode was carried out using a single cell. As a result of fuel cell test, current density of $569mA/cm^2$ at 0.3 V has been obtained for MEA contained with Pt/PPy/Nafion composite. This study shows that direct deposition of Pt catalysts on Nafion impregnated polypyrrole is a promising method to prepare thin catalyst layer for the PEMFC.

본 연구에서는 폴리피롤로 개질된 Nafion 막에 직접적으로 백금촉매를 담지하는 방법을 제시하고 PEMFC로의 응용을 검토하였다. 개시제로 $FeCl_3$ 및 $Na_2S_2O_8$을 사용하여 피롤을 Nafion 막에 중합하였다. 제저된 PPy/Nafion 복합체 막의 양이온 전도도와 함수율을 측정한 결과, $Na_2S_2O_8$을 사용하여 제조된 복합체 막은 피롤 중합시간이 증가할수록 양이온 전도도와 함수율은 감소하였고, $FeCl_3$의 경우 함수율은 감소하지만 양이온 전도도는 유지되었다. 폴리피롤로 개질된 Nafion 막에 백금 촉매를 화학적 환원법에 의해 함침한 결과, 폴리피롤의 전자 전도성 특성에 의해 백금 담지가 향상됨을 알 수 있었다. 또한 Pt/PPy/Nafion 전극촉매와 확산 전극으로 구성된 MEA를 단위 연료전지 성능평가를 행한 결과, 0.3 V의 전위에서 $569mA/cm^2$의 전류밀도 값을 갖는 연료전지 성능을 얻을 수 있었다.

Keywords

Acknowledgement

Supported by : 학술진흥재단

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