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.