Construction Of Polyoxometalate-based Metal-organic Frameworks And The Study Of Their Photocatalytic Hydrogen Evolution Property

In the past,fossil fuels have been widely used in industrial and daily life.Because of the non-renewable fossil fuels and environmental pollution caused by their combustion,more and more people pay attention to the new energy of solar energy.Polyoxometalates(POMs)have attracted considerable interest as photocatalysts for water splitting,because they can undergo fast,reversible,stepwise multiple electron transfer reactions without alteration to their structures.Metal-organic Framework(MOF)material is a kind of three-dimensional porous composite material that coordination with organic ligand and inorganic metal or metal cluster.Because of its structure porosity and stability,they can used as carrier in a variety of photocatalytic reactions and other fields.The charge of the cationic MIL-101 framework can be controlled by introducing Wells-Dawson-type POMs anions into the MOF.The cationic MIL-101 framework absorbs the anionic POMs,obtaining partially over anionic WDPOMs@MIL-101 composite to efficiently adsorb cationic photosensitizers ruthenium(II)tris(bipyridyl){Ru(bpy)32+} from the solution.The enriched photosensitizers WDPOMs@MIL-101 composites can be used in the field of photocatalytic hydrolysis of hydrogen.The resulting of heterogeneous photocatalytic hydrogen production of WDPOMs@MIL-101 composites higher than that of the corresponding WDPOMs homogeneous catalytic system.In addition,in order to prove the effectiveness and universality of the method,we also synthesized an anionic molecular cluster@Metal-organic Framework(Mo2S12@MIL-101)composites to further adsorb cationic photosensitizer {Ru(bpy)32+},it can also be used in the field of photocatalytic hydrolysis of hydrogen.These kind of materials can recycle and apply to more areas.Therefore,the main results are as follows:1.The synthesis of a series of WDPOMs@MOF composites and a molecular cluster-based Metal-organic Framework composites.The different composite materials were further confirmed by ICP,TG,XRD,FTIR,EDX and N2 Adsorption-Desorption tests.(1)P2W17(CoH2O)O61@MIL-101(PW17Co@MIL-101).A number of POM @ MOF composites were obtained by adjusting different amount of polyacid loading: Co-1,Co-2,...Co-7.(2)P2W17(NiH2O)O61@MIL-101(PW17Ni@MIL-101).A number of POM @ MOF composites were obtained by adjusting different amount of polyacid loading: Ni-1,Ni-2,......Ni-7.(3)P2W15V3O62 @MIL-101(P2W15V3@MIL-101).A number of POM @ MOF composites were obtained by adjusting different amount of polyacid loading: V-1,V-2,......V-7.(4)Mo2(S2)6@MIL-101(Mo2S12@MIL-101)2.Study on selective adsorption of anion and cations by WDPOMs@MIL-101 compositesThe WDPOMs@MIL-101 composites is an anionic framework,they can adsorptive cation composites,such as methylene blue(MB)and photosensitizer {Ru(bpy)32+}.3.Study on hydrogen production by a series of WDPOMs@MIL-101 composites and a molecular cluster metal-based organic framework composites.(1)PW17Co@MIL-101(Co-1),PW17Ni@MIL-101(Ni-1),P2W15V3@MIL-101(V-1)composites were used as catalyst in photocatalytic hydrolysis of water,corresponding to PW17 Co,PW17Ni,P2W15V3 homogeneous photocatalytic hydrolysis of water.After 8h visible light irradiation the hydrogen production WDPOM@MOF about 1.5 times higher than WDPOM.The hydrogen production is V-1> Ni-1> Co-1> P2W15V3> PW17Ni> PW17 Co.(2)Comparison of Mo2S12@MIL-101 composites and Mo2S12 photocatalytic decomposition of hydrogen production.In order to prove the universal of this method,we used Mo2S12@MIL-101 and Mo2S12 as control.After 8h visible light irradiation,Mo2S12@MIL-101 photocatalytic water decomposition of hydrogen production is about 2 times higher than Mo2S12.The rate of H2 production is 25578?mol·h-1·g-1.