Preparation, Properties And Applaications Of Metal-Organic Framework And The Derived Hierarchy Composites

Recent years, metal-organic framework, or MOFs have emerged as an extensive class of crystalline materials with enormous internal surface areas, ultrahigh porosity, unsaturated metal sites, tunable cavities and tailorable chemistry. These characteristics make themvery promising for a variety of applications, including gas storage and separation, catalysis, drug delivery and optoelectronic Materials. An increasing number of MOFs have been synthesized, but the research of MOFs still development. As the chemical tailoring and tuneable dimensionality of MOFs, a a mass of functional modified MOFs also have been sprouted. Meantime, some porous structures of special morphologies and sizes have been fabricated by using MOFs as precursors/templates. All of these broaden the application of MOFs.In recently, considerable attention has been devoted to methods for decreasing environmental contamination from organic pollutant. In this paper, magnetic MOFs as adsorbent have been fabricated by decorating dispersed Fe3O4 nanoparticles, and some porous metal/metal-oxide were made from the MOF template, and photocatalytic degradation of organic pollutant in the visible-light range. The main contents of this thesis are as follows:1. Well dispersed Fe3O4 decorated magnetic ZIF-8 nanocrystals were synthesized through a facile co-precipitation approach at room temperature. Brunauer-Emmett-Teller (BET) and magnetic hysteresis loop analysis revealed that the hybrid nanoparticles with large surface areas exhibited good magnetic properties. The magnetic Fe3O4/ZIF-8 nanocomposites were used to remove hydroquinone (HQ) from an aqueous solution. HQ adsorption kinetics followed the pseudo-second-order, and the adsorption isotherms of nanocomposites could be described very well by the Langmuir equation with ultra-high maximum adsorption capacity of 2527 mg g-1. Besides, the regeneration efficiency could remain 90% after 3 cycles of the regeneration. Along with magnetic separation ability, the as-prepared Fe3O4/ZIF-8 nanocomposites show a promising candidate for efficient wastewater purification.2. To improve the stability and photocatalytic activity of metal-oxide, the porousAg/α-Fe2O3 composites with special morphologies and sizes have been fabricated through a annealing process by using Ag+/MIL-88 as precursors/templates. This photocatalytic materials have a high surface areas compared with conventional materials. The photocatalytic degradation of Rhodamine B (RhB) over Ag/α-Fe2O3 and α-Fe2O3 are investigated. The increasing Ag content in the composite resulted in a significant increase in photocataytic activity. This result implies that the synergy between the Ag nanopaticles in α-Fe2O3 phases can make photocataytic activity improved. It will provide an new strategy to development of metal/metal-oxide composite.3. To improve the stability of metal-oxide and made to trigger photocatalytic activity in the visible region, the porous Ag/ZnO composites with special morphologies and sizes have been obtained through a two-step annealing process by using Ag+/ZIF-8 as precursors/templates. This photocatalytic material have a high surface areas compared with conventional materials. The photocatalytic degradation of methylene blue (MB) over Ag/ZnO and ZnO are investigated. The increasing Ag content in the composite resulted in a significant increase in photocataytic activity, and in the proper percentage led to a optimal photocatalytic activity. It could be widely applied in the wastewater treatment.