Synthesis of Carbon Nanotubes (CNT) by Chemical Vapor Deposition (CVD) using a biogas-based carbon precursor: A review

Abstract

Carbon is the fourth most abundant element in the universe. Among all carbon allotropes, carbon nanotube (CNT) with a cylindrical tube structure becomes an attractive carbon nanomaterial due to its unique physical and chemical properties. The typical gas sources that are usually used in CNT synthesis are mostly hydrocarbons, e.g., alcohol, methanol, methane (CH4), ethylene (C2H4), acetylene (C2H2), propane (C3H8), and cyclohexane (C6H12). Unfortunately, those carbon precursors are not environmentally friendly due to their origin from fossil fuels. Considering its continuity production, utilizing “green” alternatives and inexpensive materials will be more promising for industrial-scale production. Biogas is one of the alternative ideas as a carbon precursor in the process of CNT synthesis. Biogas consists of 40–60% methane (CH4), 40–60% carbon dioxide (CO2), and traces of nitrogen (N2), oxygen (O2), hydrogen sulfide (H2S), hydrogen (H2), and ammonia (NH3). The most commonly used to produce CNT is CH4 through chemical vapor deposition (CVD). CVD is the most expectant and scalable method for future power and electronic devices with its economical and straightforward friendly design.