Amorphous Domains in Black Titanium Dioxide

Although oxygen vacancies (Ov s) play a critical role for many applications of metal oxides, a controllable synthetic strategy for anisotropic Ov s remains a great challenge. Here, a novel strategy is proposed to achieve the regional dual structure with anisotropic Ov s at both the surface and in the interior of TiO₂ by constructing amorphous domains. The as-prepared black TiO₂ with amorphous domains exhibits superior activity in degrading rhodamine B (RhB) solutions, which can instantly decompose RhB with just a shake. First-principle simulations reveal that subsurface Ov s in TiO₂ are energetically favored, resulting in the formation of amorphous domains in the interior region via diffusion of surface-formed Ov s into the subsurface. The stable Ov -induced amorphous domains in TiO₂ with enhanced catalytic performances provide a scalable strategy to practical Ov engineering in functional metal oxides.