A general approach towards multi-faceted hollow oxide composites using zeolitic imidazolate frameworks

To realize the various functionalities and maximize the structural advantages, hollow particles with multiple compositions and complex structures are highly desirable. However, the development of a convenient and scalable method for the synthesis of such multi-compositionally complex hollow structures remains a big challenge. Herein, we report an efficient and universal strategy to fabricate a variety of porous hollow oxide nanocomposites (Co₃O₄/SiO₂, Co₃O₄/TiO₂, ZnO/SiO₂, and ZnO/TiO₂) composed of nanosized subunits, which involves a sol-gel process to form a shell onto the dodecahedral zeolitic imidazolate framework (ZIF) template and a subsequent thermolysis-induced transformation of the template at appropriate temperatures. Such a multi-compositional hollow structure with a large surface area endows the materials with exceptional properties and performances. As an example, we demonstrated that these complex hollow oxide composites, especially the Co₃O₄/SiO₂ hollow dodecahedra, exhibit a significantly enhanced photocatalytic performance as oxygen evolution photocatalysts.