Hydrogen diffusion in amorphous ZrO2

• Diffusivity and activation energies for H and H2 have been computed via molecular dynamic simulations.
• Various hydrogen transport mechanisms in amorphous zirconium oxide have been identified.
• A relation between diffusion activation energy and oxygen atomic coordination is reported.

The diffusivities and activation energies of atomic and molecular hydrogen in amorphous ZrO2 (a-ZrO2) of different densities were calculated using molecular dynamics methods. Atomic hydrogen was found to be diffusing via forming and dissociating bonds with oxygen atoms in a-ZrO2. The energy barriers for three H transport means were calculated and the most significant component of short term H transport was identified.