Water-Assisted Proton Diffusion Proton diffusion on metal oxide surfaces can play an important role in many catalytic processes. The presence of water is thought to accelerate proton diffusion. Merte et al. (p. 889 ) used high-speed, high-resolution scanning tunneling microscopy to study proton diffusion on an iron oxide. On oxygen-terminated FeO monolayer films formed on Pt, molecular water accelerated proton diffusion. Density function theory calculations implicated a H 3 O + transition state in the diffusion process.

Water-Mediated Proton Hopping on an Iron Oxide Surface