Fig. 6. Schematic illustration of the dynamic proton-concentrated catalyst surface.

The cleavage of water reactants is proceeded on WO₂ surface for the generation of protons (light blue surface), where the aggressive OH^- species can be rapidly repulsed from the electron-rich catalyst surface (orange layer), while the highly active protons prefer to transfer to the interface of WO₂ (light blue) and W (deep blue) components for the proton recombination and release of hydrogen gas.