空氣吹離法與時間因子對PEMFC CO容忍度之改善研究

Abstract

摘要 本論文可分為三大部分。第一部分為運用不同的操作條件去做暫態CO毒化實驗。暫態實驗中操作條件分別為固定電池電位(0.5、0.6、0.7 )與固定電池電流(600、1000、1200 )，CO濃度為52.7ppm。由實驗結果可知，不論定何種電位執行暫態實驗所得到的穩態毒化性能都是一樣的。但發現如果固定越高的電流去做毒化實驗，電池的CO容忍度能夠被提升，相對地有較佳的電池性能。第二部分為討論空氣吹離法與其注入時機對燃料電池CO容忍度的影響。在暫態毒化實驗中空氣注入時間分別為三分鐘與三十分鐘。結果可知不論空氣何時注入都能有效提升電池的CO容忍度，使性能回復。但空氣越早注入越能更有效降低CO毒化效應，而所需的空氣量也會因此減少。第三部分為比較不同陽極觸媒(Pt alloy and Pt)對CO容忍度之差異。當沒有配合使用空氣吹離法時，使用Pt alloy陽極觸媒可以較有效地降低毒化效應，可得到較高的電池性能。但運用空氣吹離法後，發現陽極觸媒成分對CO容忍度的影響變的不明顯。那是因為不論何種觸媒(Pt alloy and Pt)空氣吹離法都能大幅提升電池對抗CO毒化的能力。

ABSTRACT This thesis consists of three parts. The first one carries out the transient CO (52.7ppm) poisoning test with fixed cell voltage (0.5, 0.6 and 0.7V) and current density conditions (600, 1000 and 1200 ), respectively. For the fixed cell voltage case, the results of transient CO poisoning test indicate that varying cell voltage does not change the stable poisoned polarization behaviors. For the fixed current density one, the higher current density can improve CO tolerance. The second one investigates the effects of air-bleeding with different introduced timing (3 and 30min) in the transient poisoning CO tests (10.1, 25 and 52.7ppm). With air-bleeding, it is able to improve the fuel cell CO tolerance and recover the poisoned performance no matter what the air introducing timing. With an earlier introducing timing, 3min, it can obtain a better recovery performance and the optimum ratio of air-bleeding is lower. The third one studies the effect of using different anode catalyst component (Pt alloy and Pt) on the cell performance in CO poisoning tests. Without air-bleeding, Pt alloy anode catalyst has a better CO tolerance comparing to pure Pt anode catalyst. With air-bleeding, it can increase CO tolerance effectively no matter what kind anode catalyst (Pt or Pt alloy) is used.