Platinum Recycling from Fuel Cell MEA: Application of Oxygen-Free Pyrolysis,  Chloride Leaching and Hydro-Cyclone Electrowinning

Mooki Bae; Hyunju Lee; Sookyung Kim; Jong-Won Choi

doi:10.7844/kirr.2025.34.5.71

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2025 Vol.34, Issue 5 Preview Page Next Page

Research Paper

Platinum Recycling from Fuel Cell MEA: Application of Oxygen-Free Pyrolysis, Chloride Leaching and Hydro-Cyclone Electrowinning 연료전지 막전극접합체에서의 백금 재자원화: 무산소 열분해, 염산침출, 사이클론 전해채취의 적용

31 October 2025. pp. 71-81

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Abstract

This study presents an integrated approach for platinum recovery and recycling from spent fuel cell membrane electrode assemblies (MEAs) using oxygen-free pyrolysis, acid leaching, cyclone electrodeposition, and recycled electrode fabrication. Thermogravimetric analysis revealed 500–600°C as the optimal pyrolysis temperature range for effective removal of organics and fixed carbon. MEAs treated at 600°C showed over 71% Pt leaching efficiency (4800 mg/kg) under the following optimal conditions: stirring at 250 rpm, 5 g/L pulp density, 2 vol% H₂O₂, 6 M HCl, and 90°C. At 1000°C, Pt predominantly formed PtO₂, resulting in significantly reduced leaching efficiency owing to a positive Gibbs free energy (ΔG° = +32 kJ/mol) for dissolution in HCl. Cyclone electrowinning enabled rapid and efficient Pt recovery (98% in 120 min at 10 L/min) from dilute leachates. Scanning electron microscopy and X-ray diffraction analyses confirmed that the recovered Pt was highly pure and crystalline. Electrodes fabricated from cyclone-recovered Pt showed superior hydrogen evolution reaction performances compared with that of commercial Pt/C, with a lower overpotential (30 mV at 10 mA/cm²), smaller Tafel slope, and stable operation for 15 h. Overall, this study demonstrates a practical route for the efficient recovery and direct reuse of Pt from waste MEAs, supporting both high-value metal recycling and sustainable electrocatalyst production.

Keywords

Pt recovery

Fuel Cell MEA

Pyrolysis

Cyclone Electrowinning

Electrocatalyst

본 연구는 연료전지 제조공정에서 발생하는 MEA 폐촉매를 대상으로, 무산소 열분해 전처리-염산 침출-사이클론 전해채취-재활용 전극 제조로 이어지는 통합 백금 회수 및 재자원화 공정을 제안하고, 각 단계별 효율 및 소재 특성 변화를 체계적으로 평가하였다. TGA 분석 결과, 500~600°C 부근에서 MEA 내 유기물과 고정탄소가 효과적으로 제거됨을 확인하여 열처리 조건으로 선정하였다. 600°C에서 열처리한 MEA 시료의 백금 침출 실험에서는, 교반속도 250 rpm, 광액농도 5 g/L, H₂O₂ 2 vol%, 염산 6 M, 90°C 등 최적 조건에서 약 71% 이상의 침출 효율(4800 mg/kg)이 나타났다. 고온(1000°C) 열처리 시 백금이 주로 PtO₂ 형태로 변환되어, 염산 침출에서 ΔG°가 양수(+32 kJ/mol)로 전환됨에 따라 침출 효율이 현저히 저하되는 현상도 관찰되었다. 침출액 내 저농도 백금 회수를 위해 적용한 사이클론 전해채취 공정에서는 유량 10 L/min 조건에서 120분 이내에 98% 이상의 백금 회수 효율을 달성할 수 있었다. 전해로부터 회수된 백금은 XRD 및 SEM 분석을 통해 고순도, 결정성 금속 상태임이 확인되었다. 제조된 Cyclone Pt/C 전극은 상용 Pt/C 전극 대비 10 mA/cm²에서 더 낮은 과전압(30 mV), 더 작은 Tafel slope, 장시간(15시간) 내구성 유지 등 수소 발생 전극 촉매로서 뛰어난 성능과 안정성을 보였다. 이러한 결과는 폐 연료전지 MEA로부터 백금을 효율적으로 회수·재활용할 수 있는 실질적 공정 경로를 제시하며, 고부가가치 귀금속 자원순환 및 친환경 촉매 제조 분야에 기여할 수 있음을 시사한다.

키워드

백금 회수

연료전지 MEA

무산소 열분해

사이클론 전해채취

수전해 촉매

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Information

Publisher :The Korean Institute of Resources Recycling
Publisher(Ko) :한국자원리싸이클링학회
Journal Title :Resources Recycling
Journal Title(Ko) :자원리싸이클링
Volume : 34
No :5
Pages :71-81
Received Date : 2025-07-29
Revised Date : 2025-09-02
Accepted Date : 2025-09-05
DOI :https://doi.org/10.7844/kirr.2025.34.5.71

Resources Recycling ISSN:2765-3439(Print) 2765-3447(Online) 자원리싸이클링

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