On the Mechanisms of Hydrogen Spillover in MoO₃

Hydrogen spillover on the MoO3 (010) surface in the presence of a platinum catalyst was modeled using periodic density functional theory (DFT). The migration of H from a saturated Pt6 cluster to the MoO3 (010) surface was found to undergo a transition from repulsive electrostatic to attractive proton−oxygen interactions. The hydrogen is able to move nearly freely on the surface and diffuse into the bulk lattice at ambient temperatures, leading to the formation of hydrogen molybdenum bronze. We show that the high proton mobility is largely attributed to the massive H-bonding network in the MoO3 lattice.