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Calculations of adsorption energies, coadsorptions, and diffusion barriers of H atoms, and the H 2 formation on a nanographene surface (coronene)
Author(s) -
Sánchez Morella,
Ruette Fernando
Publication year - 2019
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.25893
Subject(s) - coronene , adsorption , hydrogen , desorption , diffusion , chemistry , atom (system on chip) , chemical physics , materials science , computational chemistry , crystallography , molecule , thermodynamics , physics , organic chemistry , computer science , embedded system
Adsorption and diffusion of ortho , meta , and para cis hydrogen dimers, on central and edge rings of coronene (nanographene), were studied by using the DFT‐D method, considering different multiplicities. Calculated values of adsorption energy, coadsorption energy, diffusion barriers, and reaction barriers for the H 2 formation (Langmuir‐Hinshelwood (LH) mechanism) were evaluated for ortho and para locations. The adsorption of an • H atom increases the adsorption energy of another hydrogen (coadsorption). The most stable dimers are those where an • H is adsorbed on hydrogenated‐edge sites. Dimers with multiplicity M = 1, with • H separated by an odd number of bonds, have higher coadsorption energies (higher diffusion barriers) than those where the separation is by an even number. The H 2 formation is more feasible on edge‐edge and edge‐center sites; however, on ortho hydrogenated‐edge sites, it is not energetically favored. For M = 3, H 2 formation is not observed because desorption of • H occurs.