Synthesis of aligned and length-controlled carbon nanotubes by chemical vapor deposition

Abstract

We investigated the effects of parametric synthesis conditions of catalysts such as sintering temperature, sorts of supports and compositions of catalysts on alignment and length-control of carbon nanotubes (CNTs) using catalyst powders. To obtain aligned CNTs, several parameters were changed such as amount of citric acid, calcination temperature of catalysts, and the sorts of supports using the combustion method as well as to prepare catalyst. CNTs with different lengths were synthesized as portions of molybdenum and iron using a chemical vapor deposition reactor. In this work, the mechanisms of alignment of CNTs and of the length-control of CNTs are discussed.

Novel Method of Evaluating the Purity of Multiwall Carbon Nanotubes Using Raman Spectroscopy

“…Since multiwall carbon nanotubes (MWCNTs) possess high electrical conductivity, high thermal conductivity, and excellent mechanical properties [1][2][3], they have been extensively studied for being used in the electrical, thermal, and mechanical applications [4][5][6][7]. In order to achieve better characteristics of application products, the advancement in the synthesis technology has been tried to improve the properties of MWCNTs, including crystallinity, dispersibility, and purity [8][9][10]. Among these characteristics, purity is one of the most important properties from the viewpoint of better performance of application products.…”

“…The purity was evaluated from comparing -band to -band intensity ratio ( / ) of sample with / of reference materials. MWCNTs have been synthesized by either arcdischarge [18,19] or chemical vapor deposition (CVD) [1][2][3][4][5][6][7][8][9][10]. Since the MWCNTs synthesized by arc-discharge have higher crystallinity, -band is scarcely seen in the Raman spectrum.…”

Atmospheric chemical vapor deposition of graphene on molybdenum foil at different growth temperatures

“…This method is particularly appealing because it is the most scalable and inexpensive deposition technique [5,6]. Graphene has been deposited via CVD on different transition metals (e.g., Pt [7], Pd [8], Re [9], Ni [10], Cu [3], Ru [11], Ir [12], Co [13], Rh [14], and W [15]), but very few groups have investigated the role of molybdenum (Mo) as a catalyst for graphene synthesis, despite that early studies showed that Mo may act as an effective catalyst for CNTs [16]. Also, using CVD, iron-Mo can act as a very efficient catalyst for the synthesis of single-walled and multi-walled CNTs [17].…”

Catalytic Synthesis of Substrate-Free, Aligned and Tailored High Aspect Ratio Multiwall Carbon Nanotubes in an Ultrasonic Atomization Head CVD Reactor

“…By selecting the appropriate catalyst-substrate pair, one can produce CNTs of different types, such as horizontally/ vertically aligned, short/long, and crystalline/amorphous structures [5,13,20]. Moreover, in most previous studies, CNTs were produced on a small area of substrate, which could be made of silica, alumina, zeolite, or quartz.…”