Enhancement of oxygen reduction activity of nanoshell carbons by introducing nitrogen atoms from metal phthalocyanines
Enhancement of oxygen reduction activity of nanoshell carbons by introducing nitrogen atoms from metal phthalocyanines
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DOI：
10.1016/j.electacta.2009.10.037
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发表时间：
2010-02
影响因子：
6.6
通讯作者：
J. Ozaki;S. Tanifuji;Atsuya Furuichi;Katsutoshi Yabutsuka
中科院分区：
文献类型：
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作者：
J. Ozaki;S. Tanifuji;Atsuya Furuichi;Katsutoshi Yabutsuka
纳米壳碳是一种具有中空、圆形、壳状结构的催化生长的纳米碳，其直径在约20- 50 nm的范围内。它已被证明具有氧还原反应（ORR）的电催化活性，也有望成为聚合物电解质燃料电池的非铂催化剂。本文报道了氮原子共存对纳米壳碳的ORR活性的协同增强作用。以呋喃树脂为碳源，在乙酰丙酮化物（AAs）和酞菁（Pcs）存在下，通过碳化反应制备了含Fe、Co和Ni的纳米壳碳。当使用相同的金属元素时，Pc衍生的纳米壳（MP-T系列; M=Co或Fe，T=碳化温度）显示出比AA衍生的纳米壳（MA-T系列; M=Co或Fe，T=碳化温度）更高的ORR活性。XPS研究表明，氮物种被引入到纳米壳的表面时，PCS被用作纳米壳形成催化剂，并且没有金属物种留在纳米壳上。原则上，碳的ORR活性由纳米壳的存在决定，并且可以通过引入氮原子来实现进一步增强。在80°C、0.35MPa的压力条件下，由3CoP 1000阴极和商业Pt/C阳极组成的MEA燃料电池的OCV为0.78V，最大功率密度为0.21Wcm-2。
Nanoshell carbon is a type of catalytically grown nanocarbon with a hollow, round, shell-like structure, with a diameter in the range of approximately 20–50nm. It has been shown to possess the electrocatalytic activity for oxygen reduction reaction (ORR) and is also expected to be a non-Pt catalyst for polymer electrolyte fuel cells. This paper reports the synergetic enhancement of the ORR activity of nanoshell carbons caused by the coexistence of nitrogen atoms. The nanoshell carbons were prepared by the carbonization of furan resin in the presence of acetylacetonates (AAs) and of phthalocyanines (Pcs), which contained Fe, Co, and Ni. The Pc-derived nanoshells (MP-T series; M=Co or Fe, T=carbonization temperature) showed higher ORR activities than the AA-derived nanoshells (MA-T series; M=Co or Fe, T=carbonization temperature) when the same metal elements were employed. An XPS study revealed that nitrogen species were introduced to the surface of the nanoshells when Pcs were used as the nanoshell-forming catalysts, and that no metal species remained on the nanoshells. Principally, the ORR activity of the carbons was governed by the presence of the nanoshells and further enhancement could be achieved by the introduction of nitrogen atoms. 0.78V of OCV and 0.21Wcm−2of the maximum power density were observed for a fuel cell whose MEA consisted of 3CoP1000 cathode and a commercial Pt/C anode, when it was operated at 80°C under a pressurized condition of 0.35MPa.