Synthesis of Nano-engineered Catalysts Consisting of Co₃O₄ Nanoparticles Confined in Porous SiO₂

Here we exploit zeolitic imidazolate frameworks ZIF-67 and ZIF-8 as precursors to obtain nanorattle catalysts with Co₃O₄ nanoparticles confined inside porous SiO₂ shells. The method is simple and uses zeolitic imidazolate frameworks as both structural templates and sacrificial precursors. Nanorattle catalysts of different sizes and metal loadings are designed by varying the Co/Zn ratio in the zeolitic imidazolate frameworks. It is possible to obtain different metal loadings by introduction and removal of Zn using evaporation. Moreover, all produced catalysts contained small Co₃O₄ nanoparticles. Finally, the different catalysts are tested in CO oxidation to demonstrate the effect of variations as a proof of concept. Thus, the use of metal–organic frameworks to control properties in nanorattle catalysts proposes an alternative method for the preparation of novel catalysts and shows a new pathway for synthesis of nanostructured materials.