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Comparison of Catalyst Support Degradation of PEMFC Electrocatalysts Pt/C and PtCo/C

PEMFC 전극촉매 Pt/C와 PtCo/C의 촉매 지지체 열화비교

  • Sohyeong Oh (Department of Chemical Engineering, Sunchon National University) ;
  • Yoohan Han (Department of Chemical Engineering, Sunchon National University) ;
  • Minchul Chung (Department of Chemical Engineering, Sunchon National University) ;
  • Donggeun Yoo (Department of Chemical Engineering, Sunchon National University) ;
  • Kwonpil Park (Department of Chemical Engineering, Sunchon National University)
  • 오소형 (순천대학교 화학공학과) ;
  • 한유한 (순천대학교 화학공학과) ;
  • 정민철 (순천대학교 화학공학과) ;
  • 유동근 (순천대학교 화학공학과) ;
  • 박권필 (순천대학교 화학공학과)
  • Received : 2023.01.31
  • Accepted : 2023.04.11
  • Published : 2023.08.01

Abstract

In PEMFC, PtCo/C alloy catalysts are widely used because of good performance and durability. However, few studies have been reported on the durability of carbon supports of PtCo/C evaluated at high voltages (1.0~1.5 V). In this study, the durability of PtCo/C catalysts and Pt/C catalysts were compared after applying the accelerated degradation protocol of catalyst support. After repeating the 1.0↔1.5V voltage change cycles, the mass activity, electrochemical surface area (ECSA), electric double layer capacitance (DLC), Pt dissolution and the particle growth were analyzed. After 2,000 cycles of voltage change, the current density per catalyst mass at 0.9V decreased by more than 1.5 times compared to the Pt/C catalyst. This result was because the degradation rate of the carbon support of the PtCo/C catalyst was higher than that of the Pt/C catalyst. The Pt/C catalyst showed more than 1.5 times higher ECSA reduction than the PtCo/C catalyst, but the corrosion of the carbon support of the Pt/C catalyst was small, resulting in a small decrease in I-V performance. In order to improve the high voltage durability of the PtCo/C catalyst, it was shown that improving the durability of the carbon support is essential.

PEMFC(Proton Exchange Membrane Fuel Cells)에서 PtCo/C 합금 촉매가 성능이나 내구성에서 우수하여 많이 사용되고 있다. 그러나 높은 전압에서(1.0~1.5 V) 평가되는 촉매 지지체 내구성에 관한 연구는 별로 보고 되지 않았다. 본 연구에서는 PtCo/C 촉매와 Pt/C 촉매에 촉매 지지체 가속 열화 프로토콜을 적용한 후 내구성을 비교하였다. 1.0↔1.5V 전압 변화 사이클 반복 후에 촉매 비활성도(Mass activity)와 전기화학적 활성면적(ECSA), 전기이중층 용량(DLC), Pt 용해와 입자 성장 등을 분석하였다. 전압변화 2,000 사이클 후 PtCo/C 촉매는 Pt/C 촉매에 비해 0.9 V에서 촉매 무게당 전류밀도가 1.5배 이상 감소하였다. 이와 같은 결과는 PtCo/C 촉매의 카본지지체의 열화 속도가 Pt/C 촉매보다 높기 때문이었다. Pt/C 촉매는 PtCo/C 촉매보다 촉매층의 ECSA 감소가 1.5배 이상 높았지만 Pt/C 촉매의 카본 지지체 부식이 작아 I-V 성능 감소가 작았다. PtCo/C 촉매의 고전압 내구성 향상을 위해서는 카본 지지체 내구성 향상이 필수적임을 보였다.

Keywords

Acknowledgement

본 연구는 2021년도 산업통상자원부 및 산업기술평가관리원(KEIT) 연구비 지원에 의한 연구입니다(20015756).

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