Local geometry and energetics of hydrogen in orthorhombic SrZrO3

The local geometry around hydrogen and activation energies for hydrogen transfer in undoped, Y-and Al-doped SrZO(4), have been studied using the density functional theory under the generalized gradient approximation. It is shown that strong, O-H bond is formed and orientated towards the outside of the ZrO6 octahedron in SrZrO3. The hydrogen tends to approach the dopant ion in the doped oxides. It is found that large local distortion is induced around hydrogen and dopant ion, and affects the activation energy of hydrogen transfer largely. The calculated activation energies are in agreement with the experimental values in the doped oxides.