Study of the degradation mechanisms of carbon-supported platinum fuel cells catalyst via different accelerated stress test
Study of the degradation mechanisms of carbon-supported platinum fuel cells catalyst via different accelerated stress test
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DOI：
10.1016/j.jpowsour.2014.09.012
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发表时间：
2015
影响因子：
9.2
通讯作者：
Yuanliang Zhang;Siguo Chen;Yao Wang;W. Ding;Rui Wu;Li Li-Li;X. Qi;Zidong Wei
中科院分区：
文献类型：
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作者：
Yuanliang Zhang;Siguo Chen;Yao Wang;W. Ding;Rui Wu;Li Li-Li;X. Qi;Zidong Wei
采用三种不同加速应力测试（AST）方法，结合电化学表面积（ECSA）、氧还原反应（ORR）活性、x射线光电子能谱（XPS）、透射电子显微镜（TEM）和电化学阻抗谱（EIS）响应监测，研究了碳负载铂（Pt/C）催化剂的降解机理。通过比较不同AST协议下ECSA和ORR的活动损失，我们发现AST的活动损失可分为可恢复的活动损失和不可恢复的活动损失。可恢复的活度损失是由于氧化铂的减少或部分由于碳腐蚀过程中形成的CO的去除。不可恢复的活度损失主要是由于铂的溶解/再沉积、团聚、脱离和碳腐蚀造成的。XPS结果表明，利用更负的电位窗口可以检测AST中Pt的溶解/再沉积。TEM图像和分析证实，本研究中Pt的生长方式主要是由于Pt的团聚而不是溶解/再沉积。EIS分析表明，含氧基团随时间的交替分解/形成是碳载体的主要腐蚀途径。这些发现对于理解Pt/C催化剂的降解非常重要，也有助于开发筛选新型耐用催化剂材料的快速测试方案。
A combination method based on three different accelerated stress test (AST) protocols along with the monitoring of electrochemical surface area (ECSA), oxygen reduction reaction (ORR) activities, X-Ray photoelectron spectrometer (XPS), transmission electron microscopy (TEM), and electrochemical impedance spectroscopy (EIS) response is introduced to investigate the degradation mechanisms of carbon-supported platinum (Pt/C) catalyst. By comparing the ECSA and ORR activity loss under different AST protocols, we revealed that the activity loss in AST can be divided into recoverable activity loss and unrecoverable activity loss. The recoverable activity loss is attributed to the reduction of Pt oxide or partially due to the removal of CO formed during carbon corrosion. The unrecoverable activity loss is ascribed to the Pt dissolution/re-deposition, agglomeration, detachment and carbon corrosion. XPS results show that the Pt dissolution/re-deposition in AST can be detected by using a more negative potential window. TEM images and analysis confirmed that the Pt growth mode in this study is mainly due to the Pt agglomeration rather than dissolution/re-deposition. EIS analysis reveals that the alternative decomposition/formation of oxygen containing groups over time is the main corrosion pathway of carbon support. These findings are very important for understanding Pt/C catalyst degradation and are also useful for developing fast test protocol for screening new durable catalyst materials.