Synthesis Of MOFs Derived Nitrogen-doped Porous Carbon Nanomaterial And Application In Electrochemical Sensing

Electrochemical sensing methods could achieve efficient,sensitive and specific detection of targets.Owing to its facile operation,low cost,fast response and easy miniaturization,it has drawn great attention and developed rapidly these years.The introduction of nanomaterials and biomaterials could further help to amplify the signal and improve the sensing performance.Among the numerous nanomaterials,porous carbon nanomaterial owns advantages of easy preparation,porous structure,large specific surface area,multiple active sites and good conductivity.However,pure carbon material generally has poor hydrophilicity.Besides,it suffers from disordered chemical structure and uneven pore structure attributed to the traditional synthetic methods,which restricts its further application.To solve this problem,nitrogen-doped porous carbon nanoframwork?N-CNF?was synthesized by taking nitrogen-containing MOFs?ZIF-8?as sacrificial template and using a direct calcination method.An electrochemical sensing platform was then created for determination of tannic acid.Furthermore,introduction of gold nanoparticles?AuNPs?to N-CNF helps broaden its application in electrochemical sensing fields.AuNPs served as immobilization platform for DNA.An electrochemical biosensor was then built for determination of hydroxyl radical.The main research contents and conclusions are as follows:?1?N-CNF was successfully synthesized by taking ZIF-8 as sacrificial template and using a mesoporous-silica?mSiO₂?-protected calcination strategy.The physicochemical properties and electrochemical properties of N-CNF were further studied.The results show that N-CNF owns regular dodecahedral shape as ZIF-8 with rich nitrogen and graphitic carbon inside.The specific surface area and total pore volume is 849.32 m²/g and 1.37 cm³/g,respectively,revealing that N-CNF owns large specific surface area and porous structure.Besides,the as-prepared N-CNF shows good stability and conductivity.It may contribute to the electron-transfer behavior on electrodes.Thus,N-CNF can be further utilized in electrochemical sensing fields.?2?An electrochemical sensor was created by using N-CNF as electrode material.It was further used for determination of tannic acid.The results show that the conductivity of the electrode was significantly improved after modification of N-CNF.Based on the signal amplification of N-CNF,this method could achieve sensitive detection of tannic acid.Under the optimal experimental condition,the linearity range of this method is 0.6?M²9.4?M,the limit of detection?3S/N?is 3.4?M,and the limit of quantitation?10S/N?is 11.4?M.Besides,the method also shows good reproducibility,stability and selectivity.Moreover,the recovery of this method is 90.31%¹06.20%for determination of tannic acid in real water.?3?An electrochemical biosensor was developed based on the combination of N-CNF and AuNPs.It was further used for determination of·OH.N-CNF served as loading platform for AuNPs,while AuNPs served as loading platform for ssDNA.The combination of N-CNF and AuNPs helped improve the conductivity and amplify the signal of the biosensor.·OH could cause oxidation damage to ssDNA,led to the breakage of ssDNA strand.Through the electrostatic bonding of electrochemical probe RuHex and phosphate backbone of ssDNA,the electrochemical detection of·OH could be achieved.The results show that under the optimal experimental condition,the linearity range of this method is 50?M⁵00?M,the limit of detection?3S/N?is 25?M,and the limit of quantitation?10S/N?is 83?M.Besides,the method also shows good selectivity and stability.