Formation of uncapped nanometre-sized metal particles by decomposition of metal carbonyls in carbon nanotubes
Formation of uncapped nanometre-sized metal particles by decomposition of metal carbonyls in carbon nanotubes
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DOI：
10.1039/c2sc01026g
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发表时间：
2012-01-01
期刊：
影响因子：
8.4
通讯作者：
Khlobystov, Andrei N.
中科院分区：
文献类型：
--
作者：
Chamberlain, Thomas W.;Zoberbier, Thilo;Khlobystov, Andrei N.
插入单壁碳纳米管（SWNT，直径1.5 nm）中的过渡金属（M-x（CO）（y），其中对于M = W、Re或Os，x = 1、2或3，y = 6、10或12）的羰基络合物在热处理或电子束照射下转变成金属纳米颗粒（MNP）。宿主纳米管作为一个有效的模板，控制MNP的生长，直径接近1 nm。纳米颗粒形成的唯一副产物一氧化碳（CO）气体在纳米颗粒之间产生高压袋，从而防止它们碰撞和合并成更大的结构。结果，MNP在形状上基本保持球形，并且均匀地分布在SWNT的整个长度上。尽管它们的尺寸非常小（平均每个MNP包含30-90个原子），并且它们的表面没有分子覆盖层的保护，但封装在纳米管中的金属纳米颗粒在环境条件下甚至在高温下都非常稳定。像差校正的高分辨率透射电子显微镜揭示了MNP的结晶性质，探测它们与纳米管内部的相互作用，并说明了实时和直接空间中受限MNP的复杂动力学。
Carbonyl complexes of transition metals (M-x(CO)(y), where x = 1, 2, or 3 and y 6, 10, or 12 for M = W, Re, or Os, respectively) inserted into single walled carbon nanotubes (SWNT, diameter 1.5 nm) transform into metallic nanoparticles (MNPs) under heat treatment or electron beam irradiation. The host-nanotube acts as an efficient template, controlling the growth of MNPs to similar to 1 nm in diameter. The only co-product of nanoparticle formation, carbon monoxide (CO) gas, creates pockets of high pressure between nanoparticles, thus preventing their collision and coalescence into larger structures. As a result, the MNPs stay largely spheroidal in shape and are uniformly distributed throughout the entire length of the SWNT. Despite their extremely small size (on average each MNP contains 30-90 atoms) and no protection of their surface by a capping layer of molecules, the metallic nanoparticles encapsulated in nanotubes are very stable under ambient conditions and even at elevated temperatures. Aberration-corrected high-resolution transmission electron microscopy reveals the crystalline nature of the MNPs, probes their interactions with the nanotube interior and illustrates the complex dynamics of confined MNPs in real-time and direct-space.