Preparation And Performance Study Of Core-shell Metal Organic Framework Heterogeneous Composite Materials

This study concentrated on the preparation,catalytic performance properties of MOFs composites and derivatives.and we further applied to the degradation of organic pollutant fuels.Metal-Organic Frameworks(MOFs)A novel porous material with a pore structure that is formed by the self-assembly of inorganic metal ions and organic ligands by coordination.The porous polymer has ultra-high specific surface area and porosity and structure.Flexible tunability provides an excellent platform for the development of heterogeneous catalysts,and it also makes it the best candidate for constructing biomimetic catalytic systems.This is because uniform and regular pores can produce high-density living-like sites,The metal clusters can be constructed into chemically and thermodynamically stable MOFs structures,and the closed cavities formed by the pore structure not only protect the active catalytic center,but also greatly improve the specificity of substrate selection.Therefore MOFs are ideal candidates for catalyst materials.Prussian blue crystal PBAs of different metals were synthesized by aging precipitation.Then PBAs@ZIFs were synthesized by ultrasonic temperature control.The Prussian blue crystals were used as the core,and then the ZIFs were wrapped in the outer layer of PBAs to form the core-shell type MOFs composite PBAs@ZIFs,and the material was stabilized.The PBAs@ZIFs-derived composites were obtained by calcining PBAs@ZIFs as precursors and calcining under inert gas N2 conditions at 650℃.PBAs@ZIFs and PBAs@ZIFs derived composites were applied to catalytically degrade the target Rhodamine B and methylene blue.PBAs@ZIFs and PBAs@ZIFs-derived composites completely degraded rhodamine B at room temperature for 5 min and 12 min,respectively;at the same time,PBAs@ZIFs and PBAs@ZIFs-derived composites at 4 min and 8 min completely degraded methylene blue at room temperature.The results show that the catalytic degradation follows the first-order kinetics,and the PBAs@ZIFs and PBAs@ZIFs-derived composites degrade the rhodamine B rate constant 0.745min-1,0.326 min-1;the PBAs@ZIFs and PBAs@ZIFs-derived composites degrade the methylene blue rate constant.0.802 min-1,0.796 min-1.It shows that both PBAs@ZIFs and PBAs@ZIFs derived composites have high efficiency and excellent catalytic activity.At the same time,PBAs@ZIFs derived composites still maintain more than 90%through several cycles of testing.It shows that PBAs@ZIFs derived composites have good stability.The metal-organic framework Ni-Co-BTC with different morphology and particle size was prepared by solvothermal method.By controlling the molar ratio of Ni/Co metal,the material with particle size of 100 nm-2 μm can be obtained.At the same time,Ni-Co-Cu-BTC of ternary metal was synthesized under the same experimental conditions,and then calcined under inert gas N2 conditions at 430 ℃ for 8 h to obtain Ni-Co-Cu-BTC derivative composites.The catalytic degradation of the organic dye methyl violet derived from Ni-Co-Cu-BTC was completely degraded within 10 min at room temperature.