Understanding the Chemistry of Metal Oxide to Metal-Organic Framework Reactions for Morphology Control

Metal-organic frameworks (MOFs) are a class of porous materials that have been thoroughly investigated in the past two decades; however, three-dimensional (3D) morphological control is still not established to an adequate degree. The use of metal oxides (MOs) with controllable morphology as precursors is a promising approach to overcome this limitation. Here, we investigate the formation of MOFs from different MOs and carry out a detailed case study to rationalize the factors governing the conversion of zinc oxide nanowires into ZIF-8 with the same morphology. This knowledge is then applied to generate complex 3D ZIF-8 and ZnO@ZIF-8 composite structures from different ZnO precursors. In addition, we show that this approach can be used to access new MOF structures, which are not achievable by standard synthetic methods. This study showcases how a deep understanding of the MO-to-MOF conversion can be used for the fabrication of MOF materials with precisely tailored morphology.