| Metal-organic frameworks(MOFs)have attracted much attention over the past two decades due to their unique properties,especially high surface area,high porosity,and designable functionalities,making them suitable for applications in gas adsorption and separation,catalysis and so on.However,despite all these encourage benefits offered by MOFs,their powder form makes them difficult to handle and recycle.Moreover,powder would lead to high pressure drop and tend to clog the reactor and pipes,thus limiting their application demonstration to lab-scale.In this regard,processing MOFs into monolithic composite materails is an attractive solution to address these challenges and can improve their mass transfer performance.Whereas,the fabrication methods of MOF composites still suffer from MOF agglomeration,cumbersome fabrication steps as well as low MOF ultilization rate.Precise control of the structure and increasing the content of MOF in the composite are the keys to realizing large-scale application of MOF.High internal phase emulsion(HIPE)represents a versatile and promising template to assemble nanomaterials into monolithic materials.This thesis presents a co-stabilizing strategy to construct hiearachically porous MOF/polymer composites by HIPE template.The porous structure can be well controlled and the nanoparticles can self-assemble at the interface,which significantly increase the MOF accessibility and enhance the mass transfer performance.Corresponding content are divided into three parts:(1)Interconnected porous MOF monoliths were prepared by MOF/surfactant costabilized HIPE templates.CO2 capture experiments were carried out to evaluate mass transfer performances.The pore size could be well controlled.The interconnected porous structure significantly accelerated the CO2 adsorption process,as well as enhanced the adsorption capacity.(2)The co-stabilization strategy was employed to prepare the first MOF stabilized water-in-oil HIPEs and the corresponding MOF-based poly-HIPEs.The effects of MOF loading on the pore structure,thermal stability,mechanical property,and MOF accessibility were systematically investigated.The obtained monolith showed enhanced mechanical properties and a hierarchically porous structure with up to 80%of MOF accessible.(3)A nearly pure MOF monolith was prepared by using amorphous MOF/metal oxide nanoparticles stabilized HIPE template,where MOF crystals formed and grew into continuous MOF skeleton in-situ at the oil/water interface.The monolith processed a good mechanical stability with ultrahigh MOF loading and low density.The BET surface area could reach as high as 961.3 m2 g-1.The as-prepared monolith exhibited high efficiency and good stability as catalysts in the Knoevenagel condensation reaction. |
