10.1021/acs.jpcc.5b09026.s003
Ryuhei Sato
Ryuhei
Sato
Shohei Ohkuma
Shohei
Ohkuma
Yasushi Shibuta
Yasushi
Shibuta
Fuyuki Shimojo
Fuyuki
Shimojo
Shu Yamaguchi
Shu
Yamaguchi
Proton Migration on Hydrated Surface of Cubic ZrO<sub>2</sub>: <i>Ab initio</i> Molecular Dynamics Simulation
American Chemical Society
2015
chain protonation reaction
H 2O adsorbates
zirconium atoms
proton transfer
ZrO 2 surface
equilibrium state
H 2O molecules chemisorbed
H 2O dissociation
proton conduction
Proton Migration
dynamics simulation
oxide surface
ab initio
H 2O molecules
OH
Hydrated Surface
h 2O molecules form
base sites
2015-12-31 00:00:00
Media
https://acs.figshare.com/articles/media/Proton_Migration_on_Hydrated_Surface_of_Cubic_ZrO_sub_2_sub_i_Ab_initio_i_Molecular_Dynamics_Simulation/2093428
The proton migration on a cubic ZrO<sub>2</sub> (110) surface is
investigated by <i>ab initio</i> molecular dynamics simulation.
H<sub>2</sub>O molecules form a hydrated multilayer on a ZrO<sub>2</sub> surface consisting of terminating H<sub>2</sub>O adsorbates and
hierarchically hydrogen-bonded H<sub>2</sub>O layers. A portion of
H<sub>2</sub>O molecules chemisorbed on zirconium atoms (Zr–OH<sub>2</sub>) dissociates into H<sup>+</sup> and OH<sup>–</sup>, forming polydentate and monodentate hydroxyls (>OH<sup>+</sup> and
Zr–OH<sup>–</sup>). The coexistence of acid and base
sites (Zr–OH<sub>2</sub> and Zr–OH<sup>–</sup>) in the equilibrium state is confirmed by analyses of both forward
and reverse reactions of H<sub>2</sub>O dissociation on the ZrO<sub>2</sub> surface. Proton hopping from Zr–OH<sub>2</sub> to
Zr–OH<sup>–</sup> occurs by both a direct proton transfer
and a chain protonation reaction via surrounding H<sub>2</sub>O molecules.
During these processes, Zr–OH<sub>2</sub> donates an extra
proton to Zr–OH<sup>–</sup> directly or via H<sub>2</sub>O molecules in the multilayers, indicating that the coexistence of
Zr–OH<sub>2</sub> and Zr–OH<sup>–</sup> is a
necessary condition for the proton conduction on the oxide surface
with various basicities.