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General Carbon-Supporting Strategy to Boost the Oxygen Reduction Activity of Zeolitic-Imidazolate-Framework-Derived Fe/N/Carbon Catalysts in Proton Exchange Membrane Fuel Cells
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2022-06-29 , DOI: 10.1021/acsami.2c04786
Peng-Yang Zhang 1 , Xiao-Hua Yang 2, 3 , Qiao-Rong Jiang 1 , Pei-Xin Cui 4 , Zhi-You Zhou 1 , Shu-Hui Sun 2 , Yu-Cheng Wang 1 , Shi-Gang Sun 1
Affiliation  

The oxygen reduction reaction (ORR) activity of the Fe/N/Carbon catalysts derived from the pyrolysis of zeolitic-imidazolate-framework-8 (ZIF-8) has been still lower than that of commercial Pt-based catalysts utilized in the proton exchange membrane fuel cells (PEMFCs) due to low density of accessible active sites. In this study, an efficient carbon-supporting strategy is developed to enhance the ORR efficiency of the ZIF-derived Fe/N/Carbon catalysts by increasing the accessible active site density. The enhancement lies in (i) improving the accessibility of active sites via converting dodecahedral particles to graphene-like layered materials and (ii) enhancing the density of FeNx active sites via suppressing the formation of nanoparticles as well as providing extra spaces to host active sites. The optimized and efficient Fe/N/Carbon catalyst shows a half-wave potential (E1/2) of 0.834 V versus reversible hydrogen electrode in acidic media and produces a peak power density of 0.66 W cm–2 in an air-fed PEMFC at 2 bar backpressure, outperforming most previously reported Pt-free ORR catalysts. Finally, the general applicability of the carbon-supporting strategy is confirmed using five different commercial carbon blacks. This work provides an effective route to derive Fe/N/Carbon catalysts exhibiting a higher power density in PEMFCs.

中文翻译:

提高质子交换膜燃料电池中沸石-咪唑酯骨架衍生的 Fe/N/碳催化剂的氧还原活性的一般碳支持策略

由 zeolitic-imidazolate-framework-8 (ZIF-8) 热解衍生的 Fe/N/Carbon 催化剂的氧还原反应 (ORR) 活性仍低于用于质子交换的商用 Pt 基催化剂膜燃料电池(PEMFCs)由于可接近的活性位点密度低。在这项研究中,开发了一种有效的碳负载策略,通过增加可接近的活性位点密度来提高 ZIF 衍生的 Fe/N/Carbon 催化剂的 ORR 效率。增强在于(i)通过将十二面体颗粒转化为类石墨烯层状材料来提高活性位点的可及性和(ii)提高 FeN x的密度活性位点通过抑制纳米粒子的形成以及提供额外的空间来承载活性位点。经过优化且高效的 Fe/N/Carbon 催化剂在酸性介质中与可逆氢电极相比,半波电位 ( E 1/2 ) 为 0.834 V,并在空气供给 PEMFC 中产生 0.66 W cm –2的峰值功率密度在 2 bar 的背压下,性能优于大多数先前报道的无 Pt ORR 催化剂。最后,使用五种不同的商业炭黑证实了碳支持策略的普遍适用性。这项工作提供了一种有效的途径来获得在 PEMFC 中表现出更高功率密度的 Fe/N/Carbon 催化剂。
更新日期:2022-06-29
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