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虫号: 3290608
注册: 2014-06-24
性别: MM
专业: 碳素材料与超硬材料

[交流] 用CVD方法在离子改性的石墨化碳气凝胶上生长CNTs

CVD grown CNTs within iron modiﬁed and graphitized carbon aerogel as durable oxygen reduction catalysts in acidic medium，Carbon79（2014）518-528. 影响因子：6.16

原文摘要：CNTs were grown on iron-modiﬁed mesoporous graphitized carbon aerogel (GCA) at 700 ℃,800℃and 900℃ using catalytic CVD method. Resultant CNT/GCA materials composition, morphology and structure were studied to understand their electrochemical stability and performance for oxygen reduction reaction (ORR) in acidic medium. CNT growth was increased from 700 ℃ to 800 ℃, dominated by MWCNTs formation. In the temperature range from 800 ℃to 900 ℃, the growth was reduced by forming nanoﬁber/nanoribbon structures accompanied by MWCNTs. Mesoporosity of CNT/GCA composites declined at 700 ℃and 800 ℃ due to MWCNT formation. However, CNT/GCA growth at 900 ℃improved mesoporosity with substantial increase in pore volume (～3 times of GCA) due to formation of nanoﬁbers and nanoribbons. The structure of CNT/GCAmaterials revealed nitrogen dop-ing and dispersion of FeNx phase. A synergistic contribution of CNT/GCA material structure and morphology to ORR activity was noticed. Among CNT/GCA materials, CNT-800 ℃/GCA material showed ORR activity at lowest onset potential of 0.5 V. However, CNT-900 ℃/GCA exhibits the highest ORR mass activity, with a half-wave onset potential difference of 120 mV with Pt (40 wt.%)/C. Moreover, CNT-900 ℃/GCA demonstrates high selectivity (>3.97) to 4 electron ORR path, excellent methanol tolerance and electrochemical durability which makes it a potential DMFC cathode candidate.
摘要中文翻译：用催化CVD方法，分别在700℃、800℃和900℃的条件下，在离子改性的介孔石墨化碳气凝胶（GCA）上生长CNTs。研究了合成的CNT/GCA材料的组成，形貌和结构来了解它们在酸性介质中用于氧还原反应（ORR）的电化学稳定性和性能。由700℃到800℃CNT的生长速率增加，由MWCNTs的形成控制。温度由800℃变化到900℃，生长速率降低因为伴随MWCNTs形成了纳米纤维/纳米带结构。在700℃和800℃CNT/GCA复合材料的中孔率降低因为MWCNT的形成。然而，在900℃生长的CNT/GCA提高了中孔率，因为纳米纤维和纳米带的形成大幅度提高了孔体积。CNT/GCA材料的结构呈现出掺杂的氮和分散的FeNx相。CNT/GCA材料的结构和形貌对ORR活性的协同作用是值得注意的。在CNT/GCA材料中，CNT-800℃/GCA材料呈现出ORR活性在最低的起始电压0.5V。然而，CNT-900℃/GCA表现出最高的ORR块体活性，具有起始的电势不同于120mV Pt（40wt%）/C半波。然而，CNT-900℃/GCA呈现出高选择性（大于3.97）到4电子ORR路径，极好的耐甲醇性和电化学稳定性使得该材料应用在DMFC阴极上具有很好的前景。

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