Electrochemical Synthesis Of Low-nuclearity Copper-cluster-MOFs Materials For Catalytic Oxidation And Dyes Adsorption

Metal Organic Framework(MOFs),have attracted wide attention as a new material,which can be simply self-assembled by corresponding inorganic metal ions or metal clusters and organic ligands.Because of its adjustable pores,large specific surface area and functional modification,metal-organic framework has great potential in catalysis,dye adsorption,gas storage and separation,chemical sensing and drug transport.Electrochemical synthesis method has been gradually applied to the synthesis of MOFs because of its high yield,high speed,low energy consumption,avoiding additional metal salts and mild reaction conditions.As a common non-precious metal coordination metal,Cu is widely used in MOFs synthesis because of its low price and superior performance.In this paper,the bulk crystals of compounds H-1 and H-2 were synthesized by solvothermal method.The crystal data were obtained by X-ray single crystal diffraction and the structure of the compound was obtained by analysis.Then H-1e was synthesized by electrochemical method with high efficiency and short time.In the mixed solvent of DMF/H₂O containing ligand,ionic liquid Omim BF₄ and appropriate amount of dilute hydrochloric acid were added,and copper mesh was used as cathode and anode respectively.96%yield was obtained at 20 min through screening conditions.By means of XRD,FT-IR,it was found that all the materials were synthesized successfully and had good crystallinity,and the structures of H-l and H-1e were basically the same.The morphology of H-1e was observed by OM and SEM&EDS.It was found that the particle size of H-1e was about 10?m and the elements were uniformly distributed in the compound.The results of thermogravimetric analysis showed that all the synthesized materials were stable at 200?.The oxidation of alcohols is one of the most important organic transformations in academic and industrial research.Carbonyl compounds are compounds of industrial value,which are mainly used as precursors for the manufacture of various key chemicals in the pharmaceutical and food industries.Taking the oxidation of benzyl alcohol as a model reaction,the optimal reaction conditions were obtained by screening different bases and solvents by simple H-1e.Comparing the catalytic performance of three kinds of crystals H-1,H-1e and H-2,it is found that H-1e with smaller size and pore structure has the best catalytic effect.A series of aerobic oxidation reactions catalyzed by H-1e have achieved good yields,and the reactions have significant size selectivity due to the pores in the materials.The yield and selectivity of small molecular substrates are 99%at 8 h,and a higher yield can be obtained after the reaction of large substrates for 16 h.Through four catalytic cycle tests,it is found that the material has excellent stability and recyclability.In recent years,with the development of economy,a large number of dyes used in industry are discharged,and the problem of water pollution is becoming more and more serious.The adsorption method shows excellent ability in treating dyes in water.Taking advantage of the high stability of materials in aqueous solution,the adsorption properties of H-1e for rhodamine B(Rh B),methylene blue(MB),malachite green(MG),orange G(OG)and methyl orange(MO)in water were studied.The experimental results show that the maximum adsorption amount of cationic dyes MG and MB with concentration of 100 mg·L^-1 is 396.23 mg·g^-1 and 377.2 mg·g^-1,respectively,and the adsorption rate is fast,but almost no adsorption for anionic dyes.Cationic dyes can be selectively separated from mixed dye solutions and can be recycled.It shows that H-1e material has great potential in catalytic oxidation of alcohols and treatment of water pollution.