Jeong Beomgyun, Shin Dongyoon, Jeon Hongrae, Ocon Joey D, Mun Bongjin Simon, Baik Jaeyoon, Shin Hyun-Joon, Lee Jaeyoung
School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (South Korea).
ChemSusChem. 2014 May;7(5):1289-94. doi: 10.1002/cssc.201301374. Epub 2014 Apr 3.
Platinum (Pt) is the best electrocatalyst for the oxygen reduction reaction (ORR) in hydrogen fuel cells, but it is an extremely expensive resource. The successful development of a cost-effective non-Pt ORR electrocatalyst will be a breakthrough for the commercialization of hydrogen-air fuel cells. Ball milling has been used to incorporate metal and nitrogen precursors into micropores of carbon more effectively and in the direct nitrogen-doping of carbon under highly pressurized nitrogen gas in the process of the preparation of non-noble ORR catalysts. In this study, we first utilize ball milling to excavate the ORR active sites embedded in Fe-modified N-doped carbon nanofibers (Fe-N-CNFs) by pulverization. The facile ball-milling process resulted in a significant enhancement in the ORR activity and the selectivity of the Fe-N-CNFs owing to the higher exposure of the metal-based catalytically active sites. The degree of excavation of the Fe-based active sites in the Fe-N-CNFs for the ORR was investigated with cyclic voltammetry, X-ray photoelectron spectroscopy, and pore-size distribution analysis. We believe that this simple approach is useful to improve alternative ORR electrocatalysts up to the level necessary for practical applications.
铂（Pt）是氢燃料电池中氧还原反应（ORR）的最佳电催化剂，但它是一种极其昂贵的资源。成功开发出具有成本效益的非铂ORR电催化剂将是氢空气燃料电池商业化的一项突破。在制备非贵金属ORR催化剂的过程中，球磨已被用于更有效地将金属和氮前驱体引入碳的微孔中，以及在高压氮气下对碳进行直接氮掺杂。在本研究中，我们首先利用球磨通过粉碎挖掘嵌入在铁改性氮掺杂碳纳米纤维（Fe-N-CNFs）中的ORR活性位点。由于金属基催化活性位点的更高暴露，这种简便的球磨过程导致Fe-N-CNFs的ORR活性和选择性显著提高。通过循环伏安法、X射线光电子能谱和孔径分布分析研究了Fe-N-CNFs中用于ORR的铁基活性位点的挖掘程度。我们相信，这种简单的方法有助于将替代ORR电催化剂改进到实际应用所需的水平。
