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Fe/N/C Nanotubes with Atomic Fe Sites: A Highly Active Cathode Catalyst for Alkaline Polymer Electrolyte Fuel Cells
ACS Catalysis ( IF 11.3 ) Pub Date : 2017-08-29 00:00:00 , DOI: 10.1021/acscatal.7b02340
Huan Ren , Ying Wang , Yao Yang 1 , Xun Tang , Yanqiu Peng , Hanqing Peng , Li Xiao , Juntao Lu , Héctor D. Abruña 1 , Lin Zhuang
Affiliation  

Fe-containing N-doped carbons (Fe/N/C) are a promising Pt-alternative catalyst for the oxygen reduction reaction (ORR) and are believed to be more stable in alkaline media than in acids and thus particularly suitable to be applied as the cathode catalyst for alkaline polymer electrolyte fuel cells (APEFCs). However, there has hitherto been no successful report on high-performance APEFC based on the Fe/N/C cathode, the reason for which is still not quite clear. Here we report a high-performance Fe/N/C catalyst and its application in APEFC. The catalyst precursor is adenosine, an environmentally benign N-rich biomolecule, which is polymerized via a solvothermal process and then carbonized through pyrolysis. The resulting Fe/N/C nanotubes are thoroughly characterized by a variety of microscopy and spectroscopy (SEM, TEM, XRD, XPS, Raman, Mössbauer, and STEM-EELS), which reveal a high surface N/C ratio (8 at%) and atomic Fe sites well dispersed at the wall of the nanotubes. The catalytic sites are identified to be Fe–N4. The volume-specific catalytic activity of the Fe/N/C catalyst toward the ORR is as good as that of the commercial 20 wt % Pt/C catalyst in alkaline solutions, and better in durability. The electronic conductivity of Fe/N/C turns out to be trivial in rotating-disk electrode experiments but key for fuel cell tests. The APEFC with Fe/N/C cathode (2 mg/cm2 in catalyst loading) exhibits a peak power density greater than 450 mW/cm2, the thus-far highest record in the literature for APEFC using a nonprecious metal cathode. Our findings not only deepen the understanding of the structure–activity relationship of the Fe/N/C catalyst but also mark a step toward its real application in APEFC.

中文翻译:

具有原子铁位点的Fe / N / C纳米管:碱性聚合物电解质燃料电池的高活性阴极催化剂

含铁的氮掺杂碳(Fe / N / C)是用于氧还原反应(ORR)的有前途的Pt替代催化剂,据信在碱性介质中比在酸中更稳定,因此特别适合用作碱性聚合物电解质燃料电池(APEFC)的阴极催化剂。但是,迄今为止,还没有关于基于Fe / N / C阴极的高性能APEFC的成功报道,其原因仍不清楚。在这里,我们报告了高性能的Fe / N / C催化剂及其在APEFC中的应用。催化剂前体是腺苷,一种对环境无害的富氮生物分子,它通过溶剂热过程聚合,然后通过热解碳化。通过各种显微镜和光谱学(SEM,TEM,XRD,XPS,Raman,Mössbauer,和STEM-EELS),它显示出较高的表面N / C比(8 at%),并且原子Fe位置很好地分散在纳米管的壁上。催化部位被确定为Fe–N4。Fe / N / C催化剂对ORR的体积比催化活性与碱溶液中商用20 wt%Pt / C催化剂的体积比催化活性一样好,并且耐久性更好。在转盘电极实验中,Fe / N / C的电子电导率微不足道,但却是燃料电池测试的关键。具有Fe / N / C阴极(催化剂负载量为2 mg / cm 2)的APEFC的峰值功率密度大于450 mW / cm 2,这是迄今为止使用非贵金属阴极的APEFC的最高记录。我们的发现不仅加深了对Fe / N / C催化剂的结构-活性关系的理解,而且标志着其在APEFC中的实际应用迈出了一步。
更新日期:2017-08-30
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