Recent Advances in the Flame Synthesis of Carbon Nanotubes

Abstract

Significant progress has been made not only in improving the yields of carbon nanotubes, but also in gaining a profound fundamental understanding of the growth processes. Flames are emerging as a powerful tool for the synthesis of carbon nanotubes and carbon nanofibers. The flame volume provides a carbon-rich chemically reactive environment capable of generating nanostructures during short residence times in a continuous single-step process. The present work provides a concise review of the advances made over the past two decades in the areas of flame synthesis of carbon nanotubes and carbon nanofibers. An overview of existing flame methods to synthesize carbon nanotubes is first provided. Various catalytic materials, fuel types, and flame configurations have been employed in an attempt to achieve controlled synthesis of carbon nanotubes and carbon nanofibers. Diffusion and premixed flames in counter-flow and co-flow geometries are also discussed. Various hydrocarbon fuels, oxygen enrichment, and dilution with inert gases are then examined in detail. The ability to synthesize and control carbon nanotubes and carbon nanofibers is essential for the fabrication of nanomechanical and electrical devices. A fundamental understanding of the growth mechanism and development of control methods is critically important to address these issues. The purpose of the present review is to clarify the growth mechanisms and achieve controlled flame synthesis of carbon nanotubes and carbon nanofibers.

Effect of milling process on particle size, morphology and magnetization in non-stoichiometric Fe2O3-MnO2.

“…The processes used on the products and materials result from the characteristics or properties defined by customers or users [1,2], in the advanced materials the process is a specific requirement to have a control on morphology, size particle, properties, structure, mechanical resistance, magnetization, electric resistance [3,4,5], on results published in different investigations on synthesis methods as co-precipitation, sol gel, ceramic, electrochemical, polyol, flame and others has been analyzed the characteristics and properties [4,[6][7][8][9][10][11], in the case of high energy milling environmentally contributed in synthesis to avoid hazardous waste, it is a sustainable processes [12] and a simple method suitable for the production of powders composed of fine particles. There are two ways to carry out the synthesis, dry and wet; the dry way is preferable because the reactions are faster and with a lower pollution level than the wet on [13].…”