title: Density functional theory study of ethanol decomposition on 3Ni/α-Al₂O₃(0001) surface.
abstract: We have investigated the decomposition of ethanol (EtOH) on a 3Ni/α-Al₂O₃(0001) surface using periodic density functional theory calculations. A triangular Ni trimer doped on a 2 × 2 α-Al₂O₃(0001) surface was used to represent the 3Ni/α-Al₂O₃(0001) surface. We considered several possible pathways for EtOH decomposition over the 3Ni/α-Al₂O₃(0001) surface, including dehydrogenation and C-C bond cleavage. Our calculated results indicated that (i) the 3Ni/α-Al₂O₃(0001) surface possesses high activity to inhibit coke formation and (ii) the CH₂CH₂O((a)) → CH₂CHO((a)) + H((a)) reaction is the rate-determining step for the overall reaction [CH₃CH₂OH((a)) → CH(2(a)) + CO((a)) + 4 H((a))] with an energy barrier of 1.20 eV. One feasible channel leading to C-C bond cleavage is weakening of the C-C bond in the stable CH₂CO intermediate via transformation of the adsorbed structure to a metastable structure, thereby increasing the coordination number of the two C atoms to the Ni trimer. In addition, we also investigated the nature of the metal-ethanol bonding through scrutiny of density of states (DOS) and electron density difference contour plots. The DOS analysis allowed us to characterize the state interactions between ethanol and the surfaces; the electron density difference plots provide evidence that is consistent with the prediction from DOS analysis.
authors.affiliation: Department of Chemical Engineering, National Taiwan University of Science and Technology, 43, Keelung Road, Section 4, Taipei, 106, Taiwan.
authors.forename: Hsin-Ni
authors.initials: HN
authors.lastname: Chiang
authors.forename: Chia-Ching
authors.initials: CC
authors.lastname: Wang
authors.forename: Ya-Chin
authors.initials: YC
authors.lastname: Cheng
authors.forename: Jyh-Chiang
authors.initials: JC
authors.lastname: Jiang
authors.forename: Horng-Ming
authors.initials: HM
authors.lastname: Hsieh