The Preparation Of Fe-based Hypercrosslinked Polymer Materials And Application In Catalysis

Supported metal catalysts occupy an important position in the field of catalysis.Hypercrosslinked polymers are used as carriers to prepare heterogeneous catalysts.However,the structure,morphology and loading mode of the carriers after loading have changed the chemical environment around the catalytically active sites.The optimal conditions for catalyst synthesis were explored through various control variables,and it was more difficult for the substrate to approach the active site.Therefore,one of the ideas of this thesis is to use the advantages of the hyper-crosslinked polymer synthesis strategy to explore the simple and efficient method for synthesizing heterogeneous catalysts by functionally designing monomers to anchor metals and weaving porous organic materials.In addition,it is necessary to develop cheap metal catalysts.A large number of studies have proved that iron-carbon compounds and iron-nitrogen compounds have electronic structures similar to noble metals?Pt,Pd,etc.?and have considerable catalytic activity.Therefore,it is valuable to investigate the synthesis and application of Fe-based heteroatom-doped carbon catalysts.The thesis mainly includes the following:?1?Improved homogeneous catalyst bis?diphenylphosphine?ferrocene?DPPF?and its catalytic performance:The resulting HCP-DPPF exhibited remarkable catalytic activity and excellent durability for the Cr?VI?removal and reduction of 4-nitrophenol?4-NP?to 4-aminophenol?4-AP?in an aqueous solution.The results illustrate in situ immobilization of DPPF onto hyper-cross-linked polymers which improve the stability and electron transfer of the catalyst,while enhancing the activity of HCP-DPPF toward Cr?VI?removal and reduction of 4-NP.?2?The iron-porphyrin-modified lignin polymer?P-?L-FeTPP??was synthesized,and iron-porphyrin was used as the active center under solvent-free conditions,which effectively catalyzed the cycloaddition reaction of epoxide and CO₂.After 12 h reaction at 1 MPa CO₂ and 70°C,the product yield reached 99.6%.TON reached 1481,indicating that the catalyst is more active than its homogeneous catalyst.?3?In this paper,we explore the Fe-based hypercrosslinked polymer and ZIF-8composite material derived Fe₃O₄ enhance the oxygen reduction performance of Fe-NC catalyst.The optimal catalyst FeTPP_0.64-NC-800 was obtained by doping ZIF-8 at different ratios and pyrolysis at different temperatures.The limiting current density reached 5.1 mA·cm^-2,while the commercial 20 wt%Pt/C was 4.7 mA·cm^-2.Ag/AgCl is the reference electrode,the corresponding half-wave potentials and initial potentials are-0.14 V and-0.055 V,which are close to-0.12 V and-0.035 V of commercial Pt/C.XPS comparative analysis and electrochemical test of different comparative catalysts confirmed that Fe₃O₄ can change the electronic structure of the surrounding active sites,thereby improving the intrinsic catalytic activity of the catalyst.In addition,the catalyst also shows good stability and methanol resistance.