Effectiveness factor of Pt utilization in cathode catalyst layer of polymer electrolyte fuel cells
Effectiveness factor of Pt utilization in cathode catalyst layer of polymer electrolyte fuel cells
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DOI：
10.1139/v08-053
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发表时间：
2008-07
影响因子：
1.1
通讯作者：
Z. Xia;Qianpu Wang;M. Eikerling;Zhong‐sheng Liu
中科院分区：
文献类型：
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作者：
Z. Xia;Qianpu Wang;M. Eikerling;Zhong‐sheng Liu
在这项工作中，我们分析了在全氟磺酸盐离聚物（PFSI）粘结的聚合物电解质燃料电池阴极催化剂层的铂利用率的有效因素。我们将Pt利用率的有效因子定义为特定催化剂层设计表现出的电流转化表观速率除以在指定电极过电位和外部提供的反应物浓度下在电化学反应中同等使用所有Pt原子时获得的理想速率。该定义包括所有相关尺度的统计因素以及操作下反应速率分布的不均匀性。我们的模型是基于催化剂层的随机复合团聚形态。它解释了传输现象和电化学动力学的相互作用。在介观尺度上，Pt在团聚体中的利用率有限，主要是静电效应。我们确定了团聚体的有效因子的空间分布在…
In this work, we analyze effectiveness factors of Pt utilization in perfluorosulfonate ionomer (PFSI) bonded thin film cathode catalyst layers of polymer electrolyte fuel cells. We define the effectiveness factor of Pt utilization as the apparent rate of current conversion exhibited by a specific catalyst layer design divided by the ideal rate obtained if all Pt atoms were used equally in electrochemical reactions at the specified electrode overpotential and externally provided reactant concentrations. This definition includes statistical factors at all relevant scales as well as non-uniformities of reaction rate distributions under operation. Our model is based on the random composite agglomerated morphology of the catalyst layer. It accounts for the interplay of transport phenomena and electrochemical kinetics. At the mesoscopic scale, limited effectiveness of Pt utilization in agglomerates is mainly an electrostatic effect. We determined spatial distributions of effectiveness factors of agglomerates in...