Hierarchically porous Co-N-C cathode catalyst layers for anion exchange membrane fuel cells.
Hierarchically porous Co-N-C cathode catalyst layers for anion exchange membrane fuel cells.
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DOI：
10.1002/cssc.201901668
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发表时间：
2019-09
期刊：
影响因子：
8.4
通讯作者：
Junfeng Zhang;Weikang Zhu;Yabiao Pei;Yang Liu;Yanzhou Qin;Xiangwen Zhang;Qingfa Wang;Yan Yin;M. Guiver
中科院分区：
文献类型：
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作者：
Junfeng Zhang;Weikang Zhu;Yabiao Pei;Yang Liu;Yanzhou Qin;Xiangwen Zhang;Qingfa Wang;Yan Yin;M. Guiver
作为一类新型的具有三维微结构的金属-氮-碳（M-N-C）材料，咪唑骨架分子筛（ZIFs）被用来合成高活性的ORR催化剂，以替代商用Pt/C用于阴离子交换膜燃料电池。然而，为了形成有效的催化剂层（CL），必须研究ZIF衍生的催化剂的微观结构与燃料电池性能之间的关系。本研究以钴基ZIF的可控合成为基础，构建了一种多级多孔CL，以优化三相界面（TPB）和传质。使用ZIF-CB-700（95.4mW cm-2）作为阴极催化剂的功率密度比40 ℃下的ZIF-67高约4倍，并且与商业60%Pt/C催化剂（112.0mW cm-2）的功率密度相当。在线和离线测量表明，CL的形态和微观结构是至关重要的，形成活性TPB区域，主导燃料电池的性能，而不仅仅是高催化剂活性。
As a new class of metal-nitrogen-carbon (M-N-C) material with 3D microstructure, zeolitic imidazolate frameworks (ZIFs) are explored to synthesize highly active ORR catalysts as substitutes for commercial Pt/C in anion exchange membrane fuel cells. However, to form an effective catalyst layer (CL), the relationship between the microstructure of ZIF-derived catalyst and fuel cell performance must be investigated. In this work, a hierarchically porous CL based on the controllable synthesis of Co-based ZIF was constructed to optimize the triple-phase-boundary (TPB) and mass transfer. The power density with ZIF-CB-700 (95.4 mW cm-2) as cathode catalyst is about 4 times higher than that of ZIF-67 at 40 oC and is comparable to that of the commercial 60% Pt/C catalyst (112.0 mW cm-2). Both online and offline measurements suggest that the morphology and microstructure of CL is crucial to form active TPB region, dominating the fuel cell performance rather than only high catalyst activity.