The determination of catalyst stability is as important as the determination of catalyst activity but receives much less attention because of the time required for measurement. Accelerated potential cycling tests do not always reflect the conditions experienced by catalysts operating in a fuel cell environment. Pt cathode electrodes operating at high steady-state potentials (0.8–1 V) in proton exchange membrane fuel cells (PEMFCs) have been reported to degrade due to Pt migration. Whether this phenomenon also occurs in anion exchange membrane fuel cells (AEMFCs) is not clear. In this study, an AEMFC with a Pt on Vulcan® carbon (Pt/C) cathode electrode was operated at 0.9 V steady-state potential for 1500 h. The electrode activity measured using an in situ reference electrode was found to decrease with time. Two significant changes in the Pt catalyst were found; the first was that the finely dispersed Pt catalyst agglomerated on the carbon substrate to form large clusters. The second change was that Pt was found in the polymer membrane structure. The results show that AEMFCs have similar stability concerns as PEMFCs regarding Pt catalyst material at cathodes electrodes.

Graphical Abstract

催化剂稳定性的测定与催化剂活性的测定一样重要，但是由于测量所需的时间而受到的关注较少。加速的潜在循环测试并不总是能反映出在燃料电池环境中运行的催化剂所经历的条件。据报道，在质子交换膜燃料电池（PEMFC）中，在高稳态电位（0.8-1 V）下工作的Pt阴极电极会因Pt迁移而降解。目前尚不清楚这种现象是否还会在阴离子交换膜燃料电池（AEMFC）中发生。在这项研究中，在Vulcan®碳（Pt / C）阴极电极上带有Pt的AEMFC在0.9 V稳态电势下工作1500 h。发现使用原位参比电极测量的电极活性随时间降低。在铂催化剂中发现了两个重大变化；首先是精细分散的Pt催化剂在碳基材上附聚形成大簇。第二个变化是在聚合物膜结构中发现了Pt。结果表明，关于阳极电极上的Pt催化剂材料，AEMFC与PEMFC具有相似的稳定性问题。

图形概要