ZnO@ZIFs Core-Shell Single Crystals Formed By In-Situ Conversion Of ZnO Particles

Metal-organic frameworks(MOFs), a class of porous crystalline materials with high surface areas, uniform pore sizes, and tailorable surface chemistry, have attracted considerable attentions due to their promising applications in fields of gas storage, separations, heterogeneous catalysis, sensing, drug delivery, etc. Typically, MOFs are synthesized by solvothermally reacting metal ions with organic ligands in appropriate solvents. Besides metal salts, some metal oxides and hydroxides are also used to prepare ZIF materials. Controlling the morphologies of oxides we can easily get oxide@MOFs composites with different morphologies such as rods, spheres, film, etc. Besides the typical solvothemal synthesis moyhod, solvent-free synthesis can also transform oxide to MOFs. In this thesis, we synthesize Zn O@ZIFs single crystal by taking Zn O nanospheres as template with optimized experimental parameters including reaction solvents, ligand concentration, and Zn O particle sizes. The related research mainly from the following three aspects:(1) Synthesize Zn O@ZIF-8 single-crystal by taking Zn O nanospheres as template with optimized experimental parameters including reaction solvents, ligand concentration, and Zn O particle sizes. We study its structure and formation process by a varity of characterizations and discuss the effects of different experimental conditions on the single-crystal composites formation.(2) Using 4,5-dichloroimidazole and benzimidazole as ligand to synthesize singlecrystal Zn O@ZIF-71 and Zn O@ZIF-7 composites, expanding the universalty of this synthesis method.(3) Achieving the conversion from Zn O nanorods, cobalt hydroxide carbonate nanorods, cobalt hydroxide flakes to MOFs by solvent-assisted vapor synthesis. Meanwhile, detailed study the impact of solvent, concentration, temperature and other conditions for the growth of MOFs.