Amorphous Domains in Black Titanium Dioxide

Although oxygen vacancies (O_vs) play a critical role for many applications of metal oxides, a controllable synthetic strategy for anisotropic O_vs remains a great challenge. Here, a novel strategy is proposed to achieve the regional dual structure with anisotropic O_vs 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 O_vs in TiO₂ are energetically favored, resulting in the formation of amorphous domains in the interior region via diffusion of surface-formed O_vs into the subsurface. The stable O_v-induced amorphous domains in TiO₂ with enhanced catalytic performances provide a scalable strategy to practical O_v engineering in functional metal oxides.