Preparation And Catalytic Performance Of Catalysts Originated From Three Different MOFS Precursors

Metal organic frameworks(MOFs)is a class of coordination polymer with porous structure and big surface area,which is a kind of infinite orderly connected by metal ions or metal clusters with organic ligand through a three-dimensional direction.MOFs materials owns large specific surface area and high porosity,regular pore structure and adjustable properties of structure and features,and it can be applied in catalysis,gas storage,separation,drug delivery and other fields.Based on the large specific surface area,rich carbon and metal source of MOFs,it can be applied for the synthesis of nano-size porous carbon or metal compounds.This thesis mainly focuses on different MOFs as precursor or template to synthesize new nano-catalyst material with unique structure composite.According to the structure characteristics of the corresponding unique complex,we have explored its applications such as reduction of nitro-compounds in heterogeneous catalytic field.The details are as follows:1.The development of highly efficient and stable inexpensive catalysts for the reduction of 4-nitrophenol(4-NP)to 4-aminophenol(4-AP)by NaBH4 in an aqueous solution by utilizing metal-organic frameworks(MOFs)as precursor and template remains a hot topic.Herein,a simple self-template strategy was developed to synthesize porous Zn0.3Co2.7@NC catalyst by thermal annealing of the bimetallic MOFs(Zn0.3Co2.7-ZIF)crystals.The resulting Zn0.3Co2.7@NC catalyst shows a excellent catalytic activity for reduction of 4-NP and the reduction reaction was completed only in 5 min with nearly 100% conversion.The apparent rate constant for the reaction of 4-NP reduction was estimated to be 0.683 min-1.Moreover,the catalyst was extended to reduce other nitrocompounds and exhibited excellent catalytic activity.When compared to other related catalysts in literature,the rate constants of the reaction were better than the existing literature.2.Metal organic framework(MOFs),as a kind of hybrid material crystallization containing inorganic and organic compounds and extended structure coordination bond,has become a very attractive research direction in the studies of condensed matter.If the starting material,metal ions,short ligands,Co-ligands,the template,et.all are carefully chosen and correctly grouped into solid state,then the magnetic coupling organization and topology can be further adjusted or controlled.In this aspect,our study on the magnetic metal-formic acid framework of 3D two valence metal system,using protonated amine cations as template has been investigated with interesting results.In this chapter we synthesized a perovskite type catalyst originated from the precursor [NH(CH3)][Co2+(COOH)].The precursor is synthesized of cobalt nitrate,formic acid and dimethylamine in ethanol solvent.Through further pyrolysis in an inert atmosphere,getting the catalyst composed with metal cobalt coated with carbon.We applied the catalyst Co@NC for the reduction of p-nitrophenol(4-NP),getting good catalytic performance where the reaction time is 16 min with nearly 100% conversion.In addition,after three times of continuous experiment,the catalyst shows certain reuse performance.3.FeCo nanocrystals is an important magnetic metal alloys which has been applied for many areas.However,the problems of their easy oxidation and potential toxicity have impeded their wide applications.Therefore,finding a material to coat FeCo nanocrystals for their practical applications is always a hot topic scientists cared.We synthesized a catalyst originated from Prussian blue type precursor Co3[Fe(CN)6]2,and the precursor was further heated cracking in argon,getting the nitrogen doped carbon skeleton material with matallic iron and cobalt.The catalyst CoFe@NC was applied for reduction of p-nitrophenol,the reaction was completed only in 7 min with nearly 100% conversion,showing good catalytic performance.Because of its high catalytic activity,it is hopeful to bring it to more catalytic areas.