Abstract
Metal-organic frameworks (MOFs) have attracted considerable research interest because of their unique structural flexibilitywith high porosity and a variety of applications including gas separation and storage, catalysis, drug delivery, and sensors.As a special class of MOFs, zeolitic imidazolate frameworks (ZIFs) are constructed by coordination bonds between transitionmetal cations (e.g., Cd, Co, Cu, and Zn) and imidazolate linkers. In this work, porous core-shell metal oxide composites weresuccessfully obtained through solid-state thermal decomposition of the as-prepared sodalite-ZIF crystals. Specifically, one-stepor two-step pyrolysis was conducted at different temperatures, which were chosen from the thermogravimetric analysis of theZIFs, and the structural properties of the metal oxide composites were investigated by scanning electron microscopy and X-raydiffraction. The optimal oxidation condition was determined so that the ZIF crystals are thermally decomposed to metal oxidewhile maintaining their original morphology.