Preparation Of MOFs/SiO₂ Composites With Complex Structure Assisted By 3D Printing

Metal-organic frameworks?MOFs?with inorganic and organic properties,are one of the most widely studied materials in the 21st century.However,MOFs materials were solid powder with low mechanical stre ngth.In the reaction system,MOFs materials are easy to agglomerate and difficult to recycle,which limits its development to some extent.At present,MOFs materials have been combined with support materials such as carbon materials,ceramics,and polymers to improve their mechanical stability and recycleability.Silica ceramic?SiO₂?is a non-toxic material.Silica ceramic has broad prospects in many fields due to its physicochemical properties,such as low density,high temperature resistance and corrosion resistance.The SiO₂ ceramic prepared by 3D printing technology provide model support for MOFs,which can improve the mechanical strength of MOFs materials.Porous ceramic structure is easy to transport materials,which is expected to maximize the catalytic and adsorption properties of MOFs materials.In this paper,silicone acrylate(AgiSyn^{T M} 250),?-methacryloxypropyl trimethoxysilane?KH-570?,and trimethylolpropane triacrylate?TMPTA?are used as raw materials.The organic precursor resin solution of SiO₂ ceramic was printed into a three-dimensional shape by digital light processing?DLP?.SiO₂ ceramic was prepared by high-temperature pyrolysis.Subsequently,HKUST-1/SiO₂,ZIF-8/SiO₂composites were prepared by in-situ growth using silica ceramics as the substrate.The composites were characterized by FT-IR,XRD,TG,SEM,and EDS,which indicated that the target composites were sucessfully synthesized by in-situ growth method.The HKUST-1/SiO₂ composite has a good catalytic effect on the oxidation of benzyl alcohol using 2,2,6,6-tetramethylpiperidine oxide?TEMPO?as a promoter.The yield of benzaldehyde is 95%.At three cycles,the yield of benzaldehyde was still up to 73%,indicating that the HKUST-1/SiO₂ composite has a good recycling performance.ZIF-8/SiO₂ composite material has a good adsorption effect on malachite green.After five cycles of adsorption-desorption,the adsorption efficiency of ZIF-8/SiO₂ material is still higher than 80%,which indicates that it has a good recycling performance.The adsorption process follows the pseudo-second-order kinetic model.In addition,after excessive using,the two composite materials can be immersed in HCl to recover the SiO₂ ceramic.