Amorphous Domains in Black Titanium Dioxide

Abstract

Although oxygen vacancies (O_v s) play a critical role for many applications of metal oxides, a controllable synthetic strategy for anisotropic O_v s remains a great challenge. Here, a novel strategy is proposed to achieve the regional dual structure with anisotropic O_v 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 O_v s in TiO₂ are energetically favored, resulting in the formation of amorphous domains in the interior region via diffusion of surface-formed O_v s 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.

Keywords: amorphous domains; black titanium dioxide; defect engineering; oxygen vacancies.