The simultaneous synthesis of carbon dots and carbon spheres with tunable sizes using a vertical chemical vapour deposition method

Abstract

Herein we report on the direct synthesis of solid hydrophobic carbon dots (CDs) and simultaneously carbon spheres (CSs), using a vertical chemical vapour deposition (CVD) reactor. The HRTEM data indicated that the CDs and CSs originated from different carbon building blocks indicated that the CDs and CSs originated from different carbon building blocks. The CDs were obtained by reacting acetylene (C2H2) and Ar mixtures at high flow rates (>500 sccm) and high temperatures (800-1000 °C). TEM studies indicated that the CDs produced were graphene-like quantum dots that increased in size from c. 3 nm to 8 nm as the Ar flow rate (constant C2H2 flow rate) was decreased, while small solid CSs (c. 100 nm) were also synthesised in the process. The CSs had a typical spherical layered structure with no graphitic core. A mechanism to rationalise the observation that the CDs and CSs grew simultaneously by different pathways with no formation of intermediate-sized particles is given. Keywords: carbon dots, chemical vapour deposition, nanostructure, spectroscopy

Role of Different Catalysts on a Direct Growth Carbon Nanotube for Supercapacitor Electrodes

“…Either hydrogen or nitrogen gases are used to react at the surface and to maintain the high temperature and pressure of the substrate. , Precursor gases such as carbon monoxide, ethane, ethylene, acetylene, benzene, and xylene mostly contain carbon sources. Methane, ethylene, and acetylene have linear dimmers of carbon atoms and they form a straight CNT, while benzene produces a curved CNT. , Acetylene has a major influence on CNT production manufactured by the CVD method. At high concentrations of acetylene, carbon nanoparticles grow, covering the entire surface of CNTs in compact coating, and control the morphology of nanotubes .…”

“…Methane, ethylene, and acetylene have linear dimmers of carbon atoms and they form a straight CNT, while benzene produces a curved CNT. 18,19 Acetylene has a major influence on CNT production manufactured by the CVD method. At high concentrations of acetylene, carbon nanoparticles grow, covering the entire surface of CNTs in compact coating, and control the morphology of nanotubes.…”