Preparation Of Iron-Nitrogen Doped Porous Carbon Nanomaterial Modified Electrode And Their Electrochemical Sensing Performance

At present,more and more attention are paid to the harm caused by environmental pollutants to the ecological environment balance and human health.Therefore,the search for highly sensitive detection methods has become a hot issue.Among various analytical techniques,electrochemical sensing method has its unique advantages in detecting chemicals,such as simple equipment,convenient operation,rapid response,low cost,and low quantitative limit.However,there is still room for improvements in the detection effect.Recently,the modification of electrode material has become an important way to improve the efficiency of electrical analysis.Among the new materials,porous carbon-based materials show promising potential in the field of electrochemical sensing due to their unique chemical/physical properties?e.g.,thermal stability,corrosion resistance,large specific surface area,and ultra-high conductivity?.However,the pure porous carbon as electrode material has some limitations on the catalytic activity.Therefore,the iron and nitrogen elements are used at the same time to play an auxiliary role to make up for the deficiency of porous carbon material.Nevertheless,the agglomeration phenomenon of iron nanoparticles?FeNPs?can affect the catalytic activity and stability of materials,it is still a huge challenge to reasonably prepare iron-doped porous carbon materials with high catalytic activity and stability.In this paper,the materials were synthesized by pyrolysis method using metal organic framework?MOF?and natural material composite,respectively.And then the electrochemical luminescence and electrochemical platforms were constructed for hydrogen peroxide and nitrobenzene detection.There are the main research contents and conclusions:?1?The metal organic framework?MOF?NH₂-MIL-101?Fe?containing Fe,N,C elements was synthesized by hydrothermal method,and iron-nitrogen doped porous carbon composite?Fe/N-C?was successfully obtained by pyrolysis.The as-prepared material was applied to the modification of electrode,luminol as the luminescent material,so as to realize the electrochemical luminescence?ECL?detection of trace hydrogen peroxide?H₂O₂?.In the process of detection,Fe/N-C nanocomposites remarkably promoted the H2O2 to superoxide free radical transformation,then the electrochemical luminescence intensity of luminol was enhanced.The sensor system to detect H₂O₂ has an excellent linear relationship in the concentration range of 1-300 nM,and the detection limit?LOD?reaches 0.93 nM?signal-to-noise ratio?S/N?=3?.Moreover,this ECL sensor has excellent selectivity.According to the results,Fe/N-C nanocomposites significantly improved the electron transfer process and enhanced the catalytic activity of ECL sensors in the detection of trace H2O2.Simultaneously,this ECL sensing method enables the detection of H2O2 in real water samples and renal epithelial 293T cells.This method provides a new approach for the application of iron-nitrogen doped porous carbon composites in the field of electrochemical luminescence sensing of H2O2.?2?The original iron-nitrogen doped carbon structure of hemin was used,and carbon nanotubes?CNTs?were served as the support to obtain Fe-N doped porous carbon composite?Fe-N-C?as the modified electrode material after high-temperature carbonization.And it was applied to the electrochemical sensing?EC?detection of nitrobenzene.The loading of hemin on carbon nanotubes can avoid the decrease of catalytic activity which caused by the aggregation of active sites and improve the conductivity of the electrode.By comparing with the bare electrode,it was found that the Fe-N-C modified electrode significantly enhanced the detection sensitivity of electrochemical sensing for nitrobenzene.The EC sensor method laid a foundation for the application of electrochemical detection of nitrobenzene in actual wastewater.