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言語:
eng - English
日付:
2011
出版の状態:
出版
ページ:
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出版情報:
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目次:
Kinetic investigations in the oscillatory state have been carried out in order to shed light on the interplay between the complex kinetics exhibited by a proton exchange membrane fuel cell fed with poisoned H2 (108 ppm of CO) and the other in serie process. The apparent activation energy (Ea) in the stationary state was investigated in order to clarify the Ea observed in the oscillatory state. The apparent activation energy in the stationary state, under potentiostatic control, rendered (a) Ea ≈ 50–60 kJ mol–1 over 0.8 V < E < 0.6 V and (b) Ea ≈ 10 kJ mol–1 at E = 0.3 V. The former is related to the H2 adsorption in the vacancies of the surface poisoned by CO and the latter is correlated to the process of proton conductivity in the membrane. The dependence of the period-one oscillations on the temperature yielded a genuine Arrhenius dependence with two Ea values: (a) Ea around 70 kJ mol–1, at high temperatures, and (b) Ea around 10–15 kJ mol–1, at lower temperatures. The latter Ea indicates the presence of protonic mass transport coupled to the essential oscillatory mechanism. These insights point in the right direction to predict spatial couplings between anode and cathode as having the highest strength as well as to speculate the most likely candidates to promote spatial inhomogeneities.
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学位:
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