Bonding characteristics and surface reconstruction during Au adsorption and diffusion on anatase TiO₂ (101) and (001): A first-principles study

First-principles calculations were used to investigate Au adsorption and diffusion on anatase TiO 2 (101) and (001) surfaces. On these facets, Au preferentially bonds with surface oxygen, forming stronger Au-O than Au-Ti interactions while breaking original O-Ti bonds. The (101) surface exhibits asymmetric strain with dominant tensile deformation, where [010] diffusion primarily requires overcoming Au-O bond rupture. In contrast, the (001) surface shows more extensive reconstruction, with stress propagation to adjacent Ti-O units. Diffusion barriers involve both Au-O bond breaking and surface stress accommodation, with the [010] direction being energetically favored on both surfaces. The transition state structure reveals Au upward tilting and localized bond reorganization. These facet-dependent mechanisms provide atomic-scale insights into metal-oxide interactions, which are crucial for designing Au/TiO 2 catalytic systems.