Construction Of Low-dimensional Organic Framework Nanomaterials And Exploration For Application Of Their Functional Material

Low-dimensional organic framework nanomaterials are a vital branch of functional materials with porous and highly ordered crystal structure constructed from single 0-D materials,1-D materials and 2-D materials or their hierarchical hybrids.By controlling the dimensionalities at morphological and molecular levels,low-dimensional organic framework nanomaterials are endowed with unique physical/chemical characteristics or superior property（e.g.,electronics,magnetics,optics,mechanics,and thermology）due to quantum confinement effect and thus have emerged as promising candidates for molecular storage and separation,drug delivery and light therapy,electrochemical energy storage and conversion,photocatalytic devices,and so forth.Despite much investigation into their preparation and application,the research on low-dimensional organic framework nanomaterials is in dire need of the exploitation of novel approaches for efficient and controllable synthesis,the elaboration of the relationship between structure and characteristic combined with theoretical calculation,and the performance tuning of their functional materials satisfied with the specific application.Aimed at the above-mentioned issue,low-dimensional organic framework nanomaterials comprised of metal organic frameworks（MOFs）as the essential ingredient,including 2-D MOFs nanosheets,MOFs-graphene hierarchical structure and nanocage heterostructure,were synthesized and engineered to construct the corrosion-resistance coating,intelligent-healing coating,and antibacterial material with visible-light response,and investigated for their functional property on metal corrosion inhibition and visible-light photocatalytic disinfection by means of experimental method assisted with theoretical calculation.The main contents of this research include the following aspects:（1）A surfactant-assisted approach is developed by confining the pre-assembly and coordination between Cu（II）ions and porphyrin ligands in 2-D plane to build porphyrin-paddlewheel MOFs nanosheets（Cu-TCPP）with more uniform scale and higher yield than those of MOFs nanosheets obtained by traditional liquid exfoliation,and further prepare their composite coating.As proven by electrochemical methodology,corrosion-resistance coating integrated with Cu-TCPP nanosheets displays superior barrier performance against corrosive media（i.e.,H₂O and Cl^-）relative to pure sample and bulk material sample,which can be ascribed to the water resistance,ion-penetration resistance and good compatibility with polymeric matrix from Cu-TCPP nanosheets.（2）Inspired by the wide applications of MOFs in drug delivery,a nanocarrier system（Ui O-66-NH₂@r GO）consisted of“MOFs plus graphene”hierarchical material is proposed by in situ synthesis method and gallic acid（GA）stored into MOF cages by the impregnation,which possesses the prominent stability,abundant encapsulation and sustained release.The special point-by-point scanning method,monitoring the micron-grade electrochemical signals on mild steel,proves that the model coating with GA-loaded nanocarrier shows pronounced suppression against local coating delamination and active corrosion as a result of rust-induced healing at target site.（3）Layered double hydroxides（Ni Co LDH）-assembled hollow nanocages are constructed from utilizing zeolite imidazole frameworks（ZIF67）as the templates by simultaneous precipitation and acidic etching for surface growth of Ag₃PO₄ to prepare Ag₃PO₄@Ni Co LDH heterostructure.In vitro disinfection and biofilm permeation results demonstrate its remarkable photodynamic rapid sterilization performance,which depends on the intermediary role and surface plasmon resonance of emerged Ag in heterostructure to accelerate the photo-induced charge transfer process from the density-functional-theory（DFT）calculation.（4）The hierarchical structure（ZIF8@GO）integrated with zeolite imidazole frameworks and graphene oxide is constructed successfully by one-step in situ growth strategy.In vitro disinfection and biofilm ablation experiments show that the stable crystal structure,uniform distribution and flat shape contribute to the thorough photocatalytic disinfection performance of ZIF8@GO hierarchical material under visible-light irradiation.In summary,the main idea conveyed from this research is that the controllable synthesis of low-dimensional organic framework nanomaterials plays an essential role on the physical/chemical characteristics and property of nanomaterials and their functional materials.Besides,it is hoped that this work can remind researchers to pay close attention to the relationship between material structure and property and the interface effect of multi-component devices,as well as provide novel strategy for the construction of other functional materials.