Structural phase-dependent hydrogen permeation in WO3: a DFT study on lattice symmetry, free volume, and diffusion dynamics

Abstract

Tungsten trioxide (WO₃), as a typical polycrystalline metal oxide, has its lattice symmetry and atomic arrangement significantly influencing the geometric properties and hydrogen permeability of the material. Based on density functional theory (DFT), this study systematically investigates the effects of lattice parameters, pore characteristics, and interatomic interactions of different crystalline structures of WO₃ on hydrogen diffusion kinetics, in order to provide a theoretical basis for the design of special nanostructured WO₃. It is found that hexagonal WO₃, with its lower lattice density, larger free volume, and unique channel structure, shows the best performance in hydrogen atom permeation energy barrier and diffusion coefficient, and is an ideal candidate material for ultra-fast hydrogen response.