Iron porphyrin-based cathode catalysts for PEM fuel cells: Influence of pyrolysis gas on activity and stability
Iron porphyrin-based cathode catalysts for PEM fuel cells: Influence of pyrolysis gas on activity and stability
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DOI：
10.1016/j.electacta.2009.06.058
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发表时间：
2009-11-01
影响因子：
6.6
通讯作者：
Dodelet, Jean-Pol
中科院分区：
文献类型：
--
作者：
Charreteur, Fanny;Jaouen, Frederic;Dodelet, Jean-Pol
将氯化铁四甲氧基苯基卟啉(Cl-FeTMPP)浸渍到非微孔炭黑上，在950℃的NH3(模式1)或Ar(模式2)中进行热处理，制备了用于酸性介质中02还原的铁基催化剂。在燃料电池中，采用模式I的催化剂活性最高，铁体积分数为0.4wt%，在0.8V时的活性为17 mA mg(-1)。这一活性由催化剂的微孔表面积控制。在燃料电池中，采用模式2的最高活性催化剂的铁体积含量为3.7wt%，在0.8V时的活性为1.9 mA mg(-1)。在模式2中，氮和/或铁表面浓度控制着活性。在稳定性方面，当至少66wt%的ClFeTMPP浸渍在N330上并在950℃下进行Ar处理时，模式1催化剂不稳定，而模式2催化剂至少稳定15h。用66wt%的ClFeTMPP制备的催化剂在0.8V下的体积铁含量为5.2wt%，活性为1.3 mA mg(-1)。因此，在本研究中，在NH3中热解得到活性较高但不稳定的催化剂，而在Ar中热解得到活性较低但较稳定的催化剂，当ClFeTMPP负载较高时。在氩气中热解时，Cl-FeTMPP的石墨化似乎提供了稳定性。尽管过氧化氢的产率高达26%，但模式2-催化剂是稳定的；而模式1-催化剂尽管过氧化氢的产率很低，但不稳定。皇冠版权所有(C)2009由爱思唯尔有限公司出版。保留所有权利。
Fe-based catalysts for the 02 reduction in acidic medium were prepared by impregnating chloro-iron tetramethoxyphenylporphyrin (Cl-FeTMPP) on a non-microporous carbon black and heat-treating the resulting material at 950 degrees C either in NH3 (Mode 1) or in Ar (Mode 2). The most active catalyst using Mode I has a Fe bulk content of 0.4 wt% and an activity of 17 mA mg(-1) at 0.8 V in fuel cell. This activity is controlled by the microporous surface area of the catalyst. The most active catalysts using Mode 2 has an Fe bulk content of 3.7 wt% and an activity of 1.9 mA mg(-1) at 0.8 V in fuel cell. In Mode 2, the nitrogen and/or the iron surface concentrations control the activity. Concerning stability, Mode 1-catalysts are unstable while Mode 2-catalysts show stability for at least 15 h when at least 66 wt% ClFeTMPP is impregnated onto N330 and heat-treated at 950 degrees C in Ar.The catalyst made with 66 wt% Cl-FeTMPP has a bulk Fe content of 5.2 wt% and an activity of 1.3 mA mg(-1) at 0.8 V in fuel cell. Thus, in the present study, pyrolysis in NH3 gives active but unstable catalysts while pyrolysis in argon gives less active but more stable catalysts at high Cl-FeTMPP loading. Graphitization of Cl-FeTMPP during pyrolysis in argon seems to impart stability. Mode 2-catalysts are stable in spite of a high peroxide yield of 26% while Mode 1-catalysts are unstable in spite of a low 5% peroxide yield. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.