A density functional theory study on the conversion of polycyclic aromatic hydrocarbons in hydrogen plasma

Tar is the byproduct of fuel in the pyrolysis or gasification process. Hydrogen plasma could effectively promote the decomposition of tar into acetylene and hydrogen, but the detailed cracking mechanism is difficult to detect. The DMol(3) calculations, based on density functional theory (DFT), have been employed to explore the pyrolysis pathways of naphthalene. Naphthalene is chosen as the model compound for polycyclic aromatic hydrocarbons (PAHs), which are the main components of tar. Our calculations investigate that the energy barriers required for the reactions are greatly reduced due to the participation of active hydrogen atoms. Naphthalene is easily converted into acetylene, hydrogen and carbon black through two main routes. This is in good agreement with the experiment results. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.