Size-Selective Catalytic Growth of Nearly 100% Pure Carbon Nanocoils with Copper Nanoparticles Produced by Atomic Layer Deposition

Abstract

In this paper, Cu nanoparticles with narrow size distribution are synthesized by reduction of CuO films produced by atomic layer deposition (ALD), which are used as catalysts for the catalytic growth of carbon nanostructures. By properly adjusting the ALD cycle numbers, the size of produced Cu nanoparticles can be well controlled. Uniform carbon nanocoils with near 100% purity can be obtained by using 50-80 nm Cu nanoparticles, while thin straight fibers and thick straight fibers are produced by applying 5-35 and 100-200 nm Cu nanoparticles, respectively. The mechanism of the particle size-dependent growth of the carbon nanostructure was analyzed based on the experimental results and theoretical simulation. Our results can provide important information for the preparation of helical carbon nanostructures with high purity. Moreover, this work also demonstrates that ALD is a viable technique for synthesizing nanoparticles with highly controllable size and narrow size distribution suitable for studying particle size-dependent catalytic behavior and other applications.

Remarkable improvement in microwave absorption by cloaking a micro-scaled tetrapod hollow with helical carbon nanofibers

“…33,34 To obtain high-purity helical nanofibers, a uniform Cu catalyst is essential, since the morphology of this kind of nanofiber is related to the polygonal nature of Cu particles. 25,35 By optimizing the content of Cu, we obtain highpurity helical nanofibers around the T-ZnO particles. Firstly, the molar ratio of Cu to T-ZnO is controlled to be B0.6 mol%.…”

Growth of morphology-controllable carbon nanocoils from Ni nanoparticle prepared by spray-coating method

“…3d (seen enlarged image inserted) and the majorities are CNTs. In the spray-coating case, adjacent Ni nanoparticles are inclined to create polyhedral particles which perform catalytic anisotropy obviously, on the contrary, the isolated ones with smaller diameters tend to adopt spherical structures and exhibit catalytic isotropy to lower their surface energy [8] in the dip-coating case. As a consequence, the polyhedral particles catalyze the formation of CNCs while those isolated ones for that of CNTs.…”

One-Dimensional Carbon Nanostructures: Low-Temperature Chemical Vapor Synthesis and Applications

“…In terms of CNs, by applying high-temperature CVD processes, various CNs have been synthesized, including CNTs [101], nanocones [12], Y-junctions [102,103], nanocoils [104], fullerenes [105], etc. They are actually quite useful since specific CNs are preferred for some special applications [106][107][108]. However, comparing with the results achieved on metal nanocrystals [93,95,97], metal oxides, and semiconductors [92,98], the morphology control of CNs is far less precise.…”