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Strategic implementation of pulsed oxidation for mitigation of CO poisoning in polymer electrolyte fuel cells
Journal of Power Sources ( IF 9.2 ) Pub Date : 2020-06-02 , DOI: 10.1016/j.jpowsour.2020.228352
Paran Jyoti Sarma , Christopher L. Gardner , Sachin Chugh , Alok Sharma , Erik Kjeang

Hydrogen generated by reforming various hydrocarbons contains impurities such as carbon monoxide (CO) and carbon dioxide (CO2) in varying concentrations. These impurities are known to poison the platinum and platinum alloy catalysts used in polymer electrolyte fuel cells (PEFCs) even at elevated temperatures. Amongst other approaches, pulsed oxidation for CO conversion has been proposed to enable usage of impure hydrogen fuel in PEFC applications. The present work evaluates the pulsed oxidation technique experimentally for practical implementation under high CO contamination levels. The implementation and effects of key operating parameters such as pulse width, current, and threshold potential for activation are systematically analyzed in terms of CO mitigation effectiveness. These parameters determine the extent of CO stripping and consequently the performance and energy conversion efficiency of the PEFC. Implementation of pulsing at set threshold potential rather than at fixed time intervals is shown to improve performance recovery up to 95% of the baseline performance under pure hydrogen. Technical means of utilizing the electrical energy generated during pulsing are discussed and measured, indicating a boost in the overall energy efficiency of the cell. Extended duration testing shows the feasibility of this technique to sustain CO poisoning in PEFCs at practical current densities.



中文翻译:

减轻聚合物电解质燃料电池中CO中毒的脉冲氧化的战略实施

重整各种碳氢化合物产生的氢气包含一氧化碳(CO)和二氧化碳(CO 2)的浓度。已知即使在高温下,这些杂质也会使聚合物电解质燃料电池(PEFC)中使用的铂和铂合金催化剂中毒。在其他方法中,已经提出了用于CO转化的脉冲氧化,以使得能够在PEFC应用中使用不纯的氢燃料。本工作通过实验评估了脉冲氧化技术在高CO污染水平下的实际应用。根据CO缓解效果,系统分析了关键操作参数(例如脉冲宽度,电流和激活阈值电位)的实现方式和效果。这些参数决定了CO汽提的程度,进而决定了PEFC的性能和能量转换效率。在纯氢气条件下,以设定的阈值电势而不是以固定的时间间隔执行脉冲可提高性能恢复,最高可达基线性能的95%。讨论和测量了利用在脉冲过程中产生的电能的技术手段,这表明电池的整体能效得到了提高。延长的持续时间测试表明,该技术在实际电流密度下维持PEFC中CO中毒的可行性。

更新日期:2020-06-02
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