Synthesis,Structure And Photocatalytic Properties Of Porous Crystalline Materials Based On Organic Ligands Containing Nitrogen And Oxygen

Metal-Organic Frameworks（MOFs）as a new material in the field of porous materials began to enter the public in the early nineties.It is a kind of porous material with specific structure,which is synthesized by self-assembly through organic ligands with specific functional groups and inorganic metal ions or metal clusters.Because of its unique hybrid structure by organic and inorganic,the pore shape and pore size of the material can be regulated by the system,and the functional groups are easy to modify.By virtue of the higher specific surface area,porosity and special functional pore surface,MOFs are widely used in gas storage and separation,optical,electrical materials,magnetic materials,chemical sensing,catalysis and biomedical fields.In recent years,with the rapid development of MOFs in the field of porous materials,a large number of MOFs materials with special structures were synthesized,and the development of MOFs material has gradually change from the simple design of MOFs materials with unique structure to prepare a function-oriented porous material by rational design and regulation.The study on the structure of the MOFs materials provides the necessary basis for the functional study of MOFs,and the research on the functionalization of MOFs has become a hot topic in the field of porous materials.Although,MOFs materials have shown excellent performance in many fields,but there are still some important problems need to be studied in some fields.Therefore,it is great significance to design and synthesize MOFs materials with special structure and function in the development of new functional porous materials.In this paper,we reported the synthesis of a hexanuclear cobalt-clust MOF,named as[Co₃（NTB）（4,4’-bpy）_1.5（OH）₃]·DEF（Co₆-MOF）,in which Co₆（μ3-OH）₆ and 4,4’,4’’-nitrilotribenzoic acid（NTB）constituted a layer cooperating with pillar ligand 4,4’-bipyridine（4,4’-bpy）formed a 3 D structure.Co₆-MOF has the traditional 3 D pillared structure and the larger 1D carbon nanotubes.From the topological analysis,the Co₆-MOF can be reduced to a3,8-connected network with the point symbol of（4³）2(4⁶.6¹⁸.8⁴).The material exhibits good adsorption of N₂ and CO₂ because of its interlayer distance,extra-large pore volume and extra-high pore surface.In addition,Co₆-MOF can be stable in acid and alkali solution and the air.Due to the existence of hexanuclear cobalt-clust structurein Co₆-MOF,it shows good anti ferromagnetic properties.The Co₆-MOF material is particularly characterized by a special connection between the Co₆（μ3-OH）₆ and ligands,which exhibits a better catalytic effect inthe photocatalytic CO₂ reduction.In this article,we made a deep research on the catalytic properties of MOFs materials in the photocatalytic CO₂ reduction,and we also speculate on the catalytic mechanism,which had been verified by the theoretical calculation.