Study on the Influence of Ionomer on the Durability of Pt/C Catalyst
-
摘要: 离子交换树脂(Ionomer)是质子交换膜燃料电池催化层的重要组成部分,它在催化层中的主要作用是作为质子传导相传导质子.本文采用旋转圆盘电极法(RDE),在模拟燃料电池真实的运行环境(模式一)和模拟燃料电池启停环境(模式二)两种模式下,研究了Ionomer对铂碳催化剂电压循环耐久性的影响.通过相同位置透射电镜分析法(IL-TEM),分析了铂碳催化剂经历模式二耐久性测试后的结构变化.发现:Ionomer的存在可以提高铂碳催化剂的耐久性.在模式一的测试后,添加Ionomer后,其氧还原半波电位下降值△E从23mV下降至11mV;没有发生碳的腐蚀,Pt颗粒的长大是催化剂性能下降的主要原因.Ionomer的存在延缓了Pt电化学比表面积(ECSA)的降低有利于Pt活性的保持.在模式二的测试后,其氧还原半波电位下降值△E从25mV下降至5mV.除了铂颗粒的长大还发生了载体碳的腐蚀。Ionomer的存在同样可以保持Pt的活性,铂颗粒长大的主要是因为碳的腐蚀.IL-TEM分析可以看到明显的铂颗粒长大和碳腐蚀。碳载体的腐蚀造成了铂的严重流失和团聚,样品一的铂颗粒平均粒径从2.7nm增加到了3.76nm,样品二的铂颗粒平均粒径从2.44nm增加到了4.19nm.
-
关键词:
- 质子交换膜燃料电池 /
- 离子交换树脂 /
- Pt/C催化剂 /
- 耐久性 /
- 相同位置透射电镜(IL-TEM)
Abstract: Ionomer is an important part of catalytic layer in Proton exchange membrane fuel cell.membrane electrode. Its main role in the catalytic layer is to conduct protons. In this paper, the effect of ionomer on the Pt/C catalyst was studied using the rotating disk electrode (RDE) under two modes, which simulated the real operating environment (mode 1) and simulated the start-stop environment in the fuel cell (mode 2). The structural changes of Pt/C catalyst after the durability test were analyzed by identical location transmission electron microscopy (IL-TEM). The results showed that ionomer could improve the durability of Pt/C catalysts. After the durability test of mode 1, adding ionomer can reduce the △E1/2 of oxygen reduction reaction from 23mV to 11mV. There is not carbon corrosion, and the growth of Pt particles was the main reason for the degradation of Pt/C catalyst. Ionomer delayed the decrease of electrochemical specific surface area (ECSA) of Pt/C catalyst, which was beneficial to the maintenance of Pt activity. After the durability test of mode 2, adding ionomer can reduce the △E1/2 of oxygen reduction reaction from 25mV to 5mV. In addition to the growth of platinum particles, carbon corrosion occurred in the catalyst layer. The presence of ionomer can also maintain the activity of Pt, and the growth of platinum particles is mainly due to carbon corrosion. The growth of platinum particles and carbon corrosion can be clearly seen by IL-TEM. The corrosion of carbon resulted in the loss and agglomeration of platinum. The average particle size of platinum in sample 1 increased from 2.7nm to 3.76nm, while that of sample 2 increased from 2.44nm to 4.19nm. -

计量
- 文章访问数: 57
- HTML全文浏览量: 14
- 被引次数: 0