The catalyst in the CCVD of carbon nanotubes-a review

Since their discovery [Ijima, 1991, Nature, 354, 56], carbon nanotubes (CNTs) have been widely studied due to their large potential applications. First produced in arc-discharge process or by laser-ablation, the CNTs grown by catalytic chemical vapor deposition (CCVD) have been showing however a large expansion for the past decade. A fundamental question remains after this 10-year experience: What is actually the role played by the catalyst in the CCVD of CNTs? This review intends to synthesize the data published in the scientific literature on this topic in order to better understand the parameters governing the catalytic properties of the metal nanoparticles. In particular, we will discuss the influence of the composition of the catalyst material, of the morphology of the catalyst nanoparticles, of the support, of the preparation method of the nanoparticles and of the reduction pretreatment.