| Because of the rules and uniform and tunable pore structure, poros Metal-Organic Framework ?MOFs? have large specific surface area, in adsorption, catalysis, fluorescence, magnetism, drug delivery, and many other fields has a broad application prospect. Polyoxometlates ?POMs? is a kind of unique nanoscale metal oxygen cluster. The adjustable composition, structure, variety and oxygen-rich surface have a rich variety of physical and chemical properties. Very recently, more and more attention has been paid to introducing POMs into frameworks to functionalize MOF materials. To date, two main synthetic strategies have been developed to synthesize POM-based MOF materials. ?1? POMs could be used as secondary building units ?SBUs? linked by metal-organic groups to construct POM-based framework materials. ?2? MOFs materials have emerged as an interesting class of porous solids, which could act as the solid container for POMs as template.In the present work, POM-based MOF materials were obtained by the two strategies, respectively. The syntheses, structures and properties of these compounds were investigated. The new compounds were characterized by X-ray analysis, TG, IR, element analysis, SEM, TEM. And the therml stabilities, adsorption, photocatalysis, magnetic and electrochemical properties of the compounds have been partially investigated.1. A series of remarkable crystalline compounds were constructed from the different transition metal-centered, Keggin-type compounds are obtained, by hydrotheremal synthesis. Structur alanalysis reveals that the 2D metal-organic coordination polymer sheets in the compound 3 and 4 are constructed from the transition-metal ?TM? cations and the flexible N-donor ligand bix, which are further pillared by POM clusters into the 3D porous frameworks. And they can stable in aqueous solution with a wide pH range of 1 to 11, and in common organic solvents. Photocatalytic studies indicate that compounds 3 and 4 are not only active photocatalysts for degradation of rhodamine B ?RhB?, but very stable and easily separated from the photocatalytic system for reuse as well. Compound 5 contains a transition metal-centered, bicapped Keggin-type{VW12O40?VO?2} core, connected by nickel linkers into a 1-D chain. These 1D chains interdigitated with each other, achieving an interdigitated 3D supermolecular architecture. Photocatalytic studies indicate that compound 5 exhibits not only active photocatalytic degradation of dye molecules, but also selective photocatalytic activity for degradation of cationic dyes in aqueous solution.[Ni2?H2O?2?bipy?4?Hbipy?][AlW12O40]·7H2O ?1?[N12Cl2?bipy?3?Hbipy?2][SiW12O40]·2.5H2O ?2?[Ni?bix?2][YW12O40]·?H2bix?·H2O ?3?[Co?bix?2][VW12O40]·?H2bix?-H2O ?4?[Ni?bix?4V?W10?W2?O40(V?O)2] ?5?bipy= 4,4'-bipy; bix= 1,4-bis?imidazol-1-yhnethyl?-benzene2. Extended structural materials composed of transition-metal-substituted arsenicniobates and their photocatalytic activity. Polyoxoanions in 6 and 7 could be regarded as the Keggin polyoxoniobates [AsNb9V3O40] or [AsNb8V4O40] capped by four VO5 units. The high-nuclear vanadium clusters were firstly introduced into the Keggin-type arsenicniobates. Further, polyoxoanions in 6 and 7 were connected by the metal-organic linkers into the 1D chain and 2D layer-like framework, respectively. Photocatalytic studies indicated that compounds 6 and 7 are both active for photocatalytic degradation of organic dye in aqueous solution, and they are stable and easily separated from thephotocatalytic system for reuse as well.[Cu?en?2?H2O?][Cu?en?2]4{AsNb9V7O44}·8H2O ?6?[Cu?en?2?H2O?][Cu?en?2]4H{AsNb8V8O44} · 11H2O ?7?3. A series of inorganic aggregates composed of [MnV13O38]7- polyoxoanionsand transition metal cations. The structure analyses reveal that the polyoxoanions in compounds 8-10 are isostructural, which can be described as two transition metal-supported {M2?H2O?10(MnV13O38)} (M=Co2+,Mn2+and Ni2+) units connected by a K+. And then the polyoxoanions are stacked by the electrostatic interactions with other K+ and Na+ cation to form a 2D layer. The variable-temperature magnetic susceptibility of compound 8 has been studied as the example, which shows an antiferromagnetic interaction.K0.5Na2.5Co2[MnV13O38]·22H2O ?8?K1.5Na1.5Mn2[MnV13O38]·22H2O ?9?K0.5Na2.5Ni2[MnV13O38]·22H2O ?10?4. POM@MOFs were synthesized by conventional solution, realize the formation of ZIF-67 framework and POMs just successful encapsulation ZIF-67 in a cage. We obtained three different compounds:ZW-1, ZW-2, ZW-3 by adjust POMs content. After thermal treatment, three POM@Co3O4 composite materials were obtained. This method avoids using Teflon-lined autoclave, using more safly.[Co?C4H5N2?2]159H3PW12O40 ?ZW-1?[Co?C4H5N2?2]96H3PW12O40 ?ZW-2?[Co?C4H5N2?2]36H3PW12O40 ?ZW-3?PW12?Co3O4?53 ?CW-1?PW12?Co3O4?32 ?CW-2?PW12?Co3O4?12 ?CW-3?Photocatalytic study indicated that their water oxidation catalytic performance was significantly improved compared to that of the pure MOF derived nanostructure. The systematic synthesis of these composite nanocrystals allowed optimize the conditions, and the results revealed that their respective water oxidation catalytic performance could be efficiently adjusted by varying the thermal treatment temperature and the feeding amount of the POM. CW-3 water oxidation catalytic activity is comparable with those of the best existing Co3O4-based materials. |
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