The effect of current density on H2S-poisoning of nickel-based solid oxide fuel cell anodes
The effect of current density on H2S-poisoning of nickel-based solid oxide fuel cell anodes
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DOI：
10.1016/j.jpowsour.2010.09.089
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发表时间：
2011-09-01
影响因子：
9.2
通讯作者：
Brandon, N. P.
中科院分区：
文献类型：
--
作者：
Brightman, E.;Ivey, D. G.;Brandon, N. P.
含硫杂质即使在亚ppm浓度下也会对镍基SOFC阳极性能产生破坏性影响，但这种相互作用的电化学机制尚未完全了解。在这项工作中，三电极电池的Ni-Ce0.9Gd0.1O1.95/YSZ/（La0.8Sr0.2）MnO 3-x已被用于获得新的电化学数据的镍基SOFC阳极在不同的电流密度下运行在700-750 ℃的温度范围内的硫中毒行为。三电极的安排，使阳极过电位的直接测量，与并发的阻抗测量，以提供详细的电化学过程中发生在阳极硫poisoning.The初始，逐步降解暴露于0.5 ppm的H2S引起的阳极极化电阻的增加，这是几乎完全恢复的去除H2S。发现在较高电流密度下操作导致阳极极化电阻的较小增加。提出了这种初始中毒行为是由吸附的硫抑制表面扩散的H原子的活性sites.Exposure到1 ppm和3 ppm水平的H2S导致观察到的二次降解，这也是可恢复的硫去除。这种退化是由欧姆电阻增加引起的，并且在更高的温度下更严重。作者讨论了这种行为的可能解释。(C)2010 Elsevier B. V.保留所有权利。
Sulphur-containing impurities can have a damaging impact on nickel-based SOFC anode performance even at sub-ppm concentrations, but the electrochemical mechanism of this interaction is not fully understood. In this work, three-electrode cells of Ni-Ce0.9Gd0.1O1.95/YSZ/(La0.8Sr0.2)MnO3-x have been used to obtain new electrochemical data on the sulphur poisoning behaviour of Ni-based SOFC anodes operating at different current densities in the temperature range 700-750 degrees C. The three-electrode arrangement enabled direct measurement of anode overpotential, with concurrent impedance measurement to provide detail into the electrochemical processes occurring at the anode during sulphur poisoning.The initial, stepwise degradation on exposure to 0.5 ppm H2S caused an increase in anode polarization resistance, which was almost entirely recoverable on removal of H2S. Operation at higher current density was found to result in a smaller increase in anode polarization resistance. It is proposed that this initial poisoning behaviour is caused by adsorbed sulphur inhibiting surface diffusion of H atoms to active sites.Exposure to 1 ppm and 3 ppm levels of H2S led to an observed secondary degradation which was also recoverable on removal of sulphur. This degradation was caused by an increased ohmic resistance, and was more severe at higher temperatures. The authors discuss possible explanations for this behaviour. (C) 2010 Elsevier B.V. All rights reserved.