Research On The Preparation Of MOFs Derived Fe-based Catalysts And Their Properties For Hydrogenation Of Nitroarenes

Arylamines are key feedstocks and valuable intermediates in the industry for the production of dyes,pigments,agrochemicals and pharmaceuticals.Fe-based catalysts have been extensively employed for hydrogenation of nitroarenes due to their abundant,low price and catalytic activity comparable to those of precious metals(Pd,Pt,Au and Ru,etc.).However,conventional Fe-based catalysts are prone to agglomeration and migration,which leads to their reduced stability.Therefore,developing efficient and stable Fe-based catalysts to improve the catalytic performence for hydrogenation of nitroarenes is of significance.In this paper,a series of MOFs derived Fe-based catalysts were prepared from the viewpoint of improving the catalytic efficiencies and stabilities of supported Fe-based catalysts,and the relationship between their structures and catalytic activities has been explored,the main research contents are as follows:(1)Based on the hydrogen bonding,a N-containing Fe-based MOFs(denoted as Fe@HMTA MOFs)was synthesized by self-assembly method.Integrating with electrospun technique,Fe@HMTA MOFs were constructed into N-containing nanofibers(named as Fe@HMTA/CNFs).Subsequently,the N doped carbon supported Fe O_x-based catalyst(denoted as Fe O_x@CN-hpes)was prepared by the pyrolysis of Fe@HMTA/CNFs,and the effect of electrospun-dispersed method on the structural property and catalytic performance of Fe O_x-based catalyst for hydrogenation of nitroarenes was investigated.Furthermore,the catalyst(denoted as Fe O_x@CN-hpes-400)with the appropriate pyrolysis temperature could further improve hydrogenation activity and selectivity.(2)On the basis of Fe@HMTA MOFs,the spindle-shaped N-containing MIL88-HMTA was prepared by the ligand-assisted method with fumaric acid(FMA).The N-doped carbon supported Fe S_x-Fe₂O₃based catalyst(denoted as Fe S_x-Fe₂O₃@CN)was fabricated by sulfidation method.Furthermore,the effect of ligand-assisted-sulfidation strategy on the structural property and catalytic performance of Fe S_x-Fe₂O₃based catalyst was also investigated.In addition,the appropriate sulfidation ratio could effectively improve the catalytic performance of Fe S_x-Fe₂O₃@CN-8 for hydrogenation of nitroarenes.(3)According to post-modification method,the bi-MOFs(La-salen^Fe@HMTA)was synthesized from La-salen and Fe@HMTA MOFs by the coordination-assisted method.This post-modification method could immobilize the Fe atoms on their original position and prevent their agglomeration during the pyrolysis process.The developed La-salen^Fe@HMTA derived Fe La S_x-Fe S_xbased catalyst(denoted as Fe La S_x-Fe S_x-La OCl/CN)was prepared by sulfidation method.The experimental results have revealed that the post-modification-sulfidation strategy result in the synergistic effect between Fe La S_x and Fe S_x,large specific surface area,more Fe²⁺content and enhanced the electron transfer.In addition,the optimized Fe La S_x-Fe S_x-La OCl/CN-800 catalyst exhibits outstanding catalytic activity and stability for hydrogenation of nitroarenes,which has been endowed the potential application for catalytic reactions.