Chemical kinetics of catalytic chemical vapor deposition of an acetylene/xylene mixture for improved carbon nanotube production

Carbon nanotubes (CNTs) are synthesized by catalytic chemical vapor deposition (CCVD) from xylene, acetylene and their mixture. The addition of acetylene significantly increases the decomposition rate of xylene and decreases the benzene concentration in the effluent gas, as well as improving the quality of the CNTs obtained. There is a strong interaction between acetylene and xylene during the CCVD process. Various chemical components at different positions of the CVD reactor are classified and identified by mass spectrometry. Reaction kinetics constants are determined numerically based on the in situ measurement. Chemical kinetics of CCVD process is analyzed based on a detailed mechanism (88 species and 322 reactions), which successfully demonstrates the decomposition of the used carbon sources, and the synergistic effect of the addition of acetylene. The generation of hexagonal carbon rings from the dehydrogenation of benzene rings is described and discussed combined with the formation of CNT structures.