Evaluation of Ionomer Distribution on Electrocatalysts for Polymer Electrolyte Fuel Cells by Use of a Low Acceleration Voltage Scanning Electron Microscope
Evaluation of Ionomer Distribution on Electrocatalysts for Polymer Electrolyte Fuel Cells by Use of a Low Acceleration Voltage Scanning Electron Microscope
复制标题
DOI：
10.1149/1945-7111/abfa59
复制
发表时间：
2021-05
影响因子：
3.9
通讯作者：
K. Kakinuma;M. Kawamoto;Kayoko Tamoto;M. Yamaguchi;Satoru Honmura;A. Iiyama;M. Uchida
中科院分区：
文献类型：
--
作者：
K. Kakinuma;M. Kawamoto;Kayoko Tamoto;M. Yamaguchi;Satoru Honmura;A. Iiyama;M. Uchida
在不使用染色处理的情况下，使用电子显微镜对具有不同离聚物/碳混合比（I/C）的全氟磺酸离聚物（PFSI）的分散体进行定性评价。低加速电压透射电子显微镜（LAV-TEM）和超低加速电压扫描电子显微镜与减速法（ULV-SEM）使用一个典型的低加速电压，这使得敏感的离聚物形态的选择性检查。高性能的电荷耦合器件使人们能够获得高对比度的离聚物图像，而无需使用铅或铯染色，否则可能导致这些预处理过程中的形态变化。使用Pt/GCB的聚合物电解质燃料电池的电化学活性表面积随着PFSI含量的增加而增加，并且在离聚物/碳重量比（I/C）为1.2时饱和，其中通过LAV-TEM检测到离聚物的完全覆盖。ULV-SEM图像显示I/C= 1.2以上的Pt/GCB催化剂层的一次孔和二次孔的明显闭塞。通过使用淬灭固体密度泛函理论分析进行的氮气吸附测量也支持I/C= 1.2以上的Pt/GCB催化剂层的初级和次级孔的闭塞。
The qualitative evaluation of the dispersion of prefluorosulfonic ionomer (PFSI) with different ionomer/carbon mixing ratios (I/C) using electron microscopy was carried out without the use of a stain treatment. Both low acceleration voltage transmission electron microscopy (LAV-TEM) and ultralow acceleration voltage scanning electron microscopy with a retarding method (ULV-SEM) use a characteristically low acceleration voltage, which allows the selective examination of the sensitive ionomer morphology. The high-performance charge-coupled device enables one to obtain high contrast ionomer images without the use of lead or cesium staining, which could otherwise result in morphological changes during these pre-treatments. The electrochemically active surface area of the polymer electrolyte fuel cell using Pt/GCB increased with increasing PFSI content and saturated at an ionomer/carbon weight ratio (I/C) of 1.2, where full coverage of the ionomer was detected by LAV-TEM. The ULV-SEM images showed the obvious occlusion of the primary and secondary pores of the Pt/GCB catalyst layers above I/C= 1.2. The nitrogen gas adsorption measurement, carried out by use of quenched solid-density-functional theory analysis, also supported the occlusion of the primary and secondary pores of the Pt/GCB catalyst layers above I/C= 1.2.