The combined catalytic action of solid acids with nickel for the transformation of polypropylene into carbon nanotubes by pyrolysis
The combined catalytic action of solid acids with nickel for the transformation of polypropylene into carbon nanotubes by pyrolysis
复制标题
固体酸与镍的联合催化作用将聚丙烯热解转化为碳纳米管
DOI：
10.1002/chem.200601018
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发表时间：
2007-01-01
影响因子：
4.3
通讯作者：
Tang, Tao
中科院分区：
文献类型：
--
作者：
Song, Rongjun;Jiang, Zhiwei;Tang, Tao
研究了有机改性蒙脱土（OMMT）和Ni 2 O3对聚丙烯（PP）热解炭化过程的影响。TEM和拉曼光谱分析结果表明，PP的热解产物主要是多壁碳纳米管。令人惊讶的是，OMMT和Ni 2 O3的组合导致MWNTs的高产率形成。采用X射线粉末衍射（XRD）和GC-MS分析了该组合方法从PP高产率制备MWNTs的机理。通过改性剂的热分解，在降解的OMMT层中产生布朗斯台德酸位点。生成的碳正离子在PP的碳化和MWNTs的形成中起着重要的作用。碳正离子的存在诱导PP的降解，以形成主要的产物具有较低的碳数，可以很容易地由镍催化剂的MWNTs的生长催化。此外，碳正离子是活性中间体，其促进具有较高碳数的降解产物通过碳转移反应生长多壁碳纳米管。XRD测试表明，Ni 2 O3被原位还原为金属镍（Ni），为MWNTs的生长提供了活性中心。
The effects of both organically modified montmorillonite (OMMT) and Ni2O3 on the carbonization of polypropylene (PP) during pyrolysis were investigated. The results from TEM and Raman spectroscopy showed that the carbonized products of PP were mainly multiwalled carbon nanotubes (MWNTs). Surprisingly, a combination of OMMT and Ni2O3 led to high-yield formation of MWNTs. X-ray powder diffraction (XRD) and GC-MS were used to investigate the mechanism of this combination for the high-yield formation of MWNTs from PP. Bronsted acid sites were created in degraded OMMT layers by thermal decomposition of the modifiers. The resultant carbenium ions play an important role in the carbonization of PP and the formation of MWNTs. The degradation of PP was induced by the presence of carbenium ions to form predominantly products with lower carbon numbers that could be easily catalyzed by the nickel catalyst for the growth of MWNTs. Furthermore, carbenium ions are active intermediates that promote the growth of MWNTs from the degradation products with higher carbon numbers through hydride-transfer reactions. The XRD measurements showed that Ni2O3 was reduced into metallic nickel (Ni) in situ to afford the active sites for the growth of MWNTs.