Self-templated formation of AgCl/TiO2 hollow octahedra for improved visible-light photocatalytic activity

Composite semiconductor photocatalysts with hollow structures can present excellent photocatalytic performance by combining the advantages of composite photocatalyst and hollow structures. However, it is a great challenge to develop a facile synthetic route to realize the composite hollow nanostructures. In the paper, AgCl/TiO₂ composite hollow octahedra were synthesized by a facile self-templated method via the direct addition of Ag₂O octahedron template into TiCl₄ ethanol solution. In the case, AgCl and TiO₂ nanoparticles can be simultaneously formed to construct the shell of hollow octahedra along with the alcoholysis and hydrolysis of TiCl₄ and the reaction of releasing H⁺ and Cl⁻ ions with Ag₂O template. Obviously, the synthetic method showed some advantages of economic reaction steps and uniform component distribution. After AgCl/TiO₂ is illuminated by visible light, partial Ag metal can form in the sample due to the photosensitive property. Further photocatalytic results indicated that the Ag/AgCl/TiO₂ hollow octahedron photocatalyst exhibited excellent photocatalytic activity and stability of performance. Importantly, the present Ag₂O self-template method was also extended for the synthesis of other hollow octahedra such as AgCl/Bi₂O₃, AgCl/SnO₂ and AgCl. Thus, the present work may provide new insights into design and synthesis of other hollow octahedron photocatalysts.