Synthesis,Structure,and Photocatalytic Properties Of Rare-earth Metal-organic Frameworks Based On Metalloporphyrin

Porphyrins widely exist in nature mainly in the form of light-harvesting and catalytic active sites.Because porphyrin has the characteristics of rigid structure and easy-to-modify functional groups,and has excellent light absorption properties in the visible light region,it is often used as the building block for constructing of photonic functional materials.The combination of porphyrin and metal-organic framework(MOF)can be used to construct a variety of crystalline photonic functional materials with multifunctions,which expands the application fields of porphyrin.In this thesis,tetrakis(4-carboxyphenyl)porphyrin and rare earth/transition metal ions are used as precursors to construct a series of three-dimensional MOFs based on porphyrin/metalporphyrin through in-situ solvothermal synthesis and their potential photocatalytic functions are deeply studied.The crystal structures of 12 porous MOF materials(M-TCPP-Ln)show that the porphyrin center can be metallized in-situ,and only three carboxyl groups in the porphyrin ligand coordinate with rare earth metals.Through a series of characterization,it can be proved that these materials have good physical and chemical stability.M-TCPP-La materials inherits the excellent light-harvesting ability of porphyrin groups,and can produce singlet oxygen(¹O₂)and superoxide anion radical(O₂^·-)in varying degrees under visible light irradiation,which is verified by electron paramagnetic resonance and active oxygen capture experiments.In contrast,nonmetallic TCPP-La can only produce ¹O₂ under the same conditions.M-TCPP-La is used for the photocatalytic oxidation of 2-chloroethylethyl sulfide(CEES),a mustard gas simulant.The results show that CEES can be converted to non-toxic sulfoxide product(CEESO)in 5-11minutes under the synergistic effect of ¹O₂and O₂^·-,and Fe-TCPP-La shows the best catalytic efficiency.In this paper,it is found for the first time that MOF materials can efficiently and selectively catalyze the oxidation of CEES by O₂^·-under light irradiation,which provided a new way for efficient degradation of mustard gas.