Dimerization of dehydrogenated polycyclic aromatic hydrocarbons on graphene

Abstract

Dimerization of polycyclic aromatic hydrocarbons (PAHs) is an important, yet poorly understood, step in the on-surface synthesis of graphene (nanoribbon), soot formation, and growth of carbonaceous dust grains in the interstellar medium (ISM). The on-surface synthesis of graphene and the growth of carbonaceous dust grains in the ISM require the chemical dimerization in which chemical bonds are formed between PAH monomers. An accurate and cheap method of exploring structure rearrangements is needed to reveal the mechanism of chemical dimerization on surfaces. This work has investigated the chemical dimerization of two dehydrogenated PAHs (coronene and pentacene) on graphene via an evolutionary algorithm augmented by machine learning surrogate potentials and a set of customized structure operators. Different dimer structures on surfaces have been successfully located by our structure search methods. Their binding energies are within the experimental errors of temperature programmed desorption measurements. The mechanism of coronene dimer formation on graphene is further studied and discussed.

Stability of PdxOy Particles Supported on Strontium Titanate Perovskite under Three-Way Catalyst Operating Conditions: Implications for Sintering Resistance

“…The structures of Pd x O y clusters supported on STO surfaces were investigated using the global optimization with first-principles energy expression (GOFEE) algorithm, − which is based on the evolutionary algorithm and Gaussian process regression. The GOFEE method has been successfully applied for finding stable structures of supported metal clusters, , ultrathin oxide overlayer, and aromatic hydrocarbons supported on graphene . DFT calculations within GOFEE were performed using the grid-based projector augmented wave code with the Perdew–Burke–Ernzerhof (PBE) functional, double-ζ-polarized basis, and a grid spacing of ≈0.20 Å.…”