Preparation Of Porous Carbon Material And Its Application For The Detection Of Small Molecules

With the development of economy and society,people are paying more and more atten-tion to environmental pollution and physical health.The influence of many small molecules has also attracted the attention of researchers.Hydroquinone and catechol are widely used in sterilization,cosmetics,dyes and other fields,and are inevitably discharged into the nat-ural environment.Due to their high toxicity and carcinogenicity,they pose the greatest threat to the ecological environment and human health.Glucose,hydrogen peroxide,dopamine and uric acid are involved in human metabolic activities and are closely related to human health.Abnormal concentrations of these molecules in the human body can cause serious diseases.Therefore,it is necessary to detect these small molecules quickly and efficiently.Electro-chemical detection technology is admired for its advantages such as fast response,simple operation,and high sensitivity.The design of materials with excellent performance and the construction of sensors to achieve detection are the top priorities of electrochemical detec-tion.Based on these concepts,this paper describes three porous carbon materials,and estab-lishes sensors to achieve the detection of hydroquinone and catechol,glucose and hydrogen peroxide,dopamine and uric acid,respectively.（1）Polymer film was prepared via solvent evaporation self-assembly method,using F127 as template,tetraethyl orthosilicate as structural stabilizer,soluble phenolic resin as car-bon source,and cerium nitrate as modifier.Ceria/mesoporous carbon composite was synthe-sized successfully after high temperature carbonization and silicon removal.TEM charac-terization showed that ceria particles were evenly distributed on the mesoporous carbon sheet.Electrochemical test results showed that the sensor exhibited good electrocatalytic performance for the determination of hydroquinone and catechol.The detection ranges were0.5-500μM and 0.4-320μM,and the corresponding detection limits（S/N=3）of 0.24μM and 0.13μM,respectively.Meanwhile,the sensor also has good reproducibility,stability and anti-interference ability.Applied to the recovery test of spiked water in lake and tap water with satisfactory results.（2）The waste bamboo powder was dispersed in a copper nitrate solution,left to stand for 24 hours,filtered and dried to obtain a precursor,and then carbonized at high temperature to prepare a cuprous oxide/copper/biomass porous carbon composite material（Cu Ox@BPC）.Scanning electron microscopy showed that cuprous oxide/copper was uniformly distributed in the slits and folds on the surface of the carbon substrate;the results of nitrogen adsorption and desorption test showed that the introduction of copper ions increased the pore size and specific surface area.Under optimized conditions,the constructed sensor showed good de-tection performance for glucose and hydrogen peroxide with a wide detection range（glucose:0.5-4832μM,H₂O₂:1-8330μM）and low detection limit（S/N=3,glucose:0.1μM,H₂O₂:0.35μM）.The sensor also exhibited high stability,reproducibility and anti-interference abil-ity.（3）Hierarchical porous carbon was simply prepared through pyrolysis of sodium citrate and further used as modified material for the determination of dopamine and uric acid.Com-pared with a conventional glassy carbon electrode,the modified sensor achieved a larger active area and a faster electron transfer rate due to the high specific area and unique hierar-chical porous construction.It was applied to the detection of dopamine and uric acid with linear detection ranges of 0.04-100μM and 0.2-100μM,and the detection limits（S/N=3）of 0.018 and 0.07μM,respectively.In addition,the sensor is applied to simultaneous detec-tion of DA and UA in spiked samples of juice,milk and urine samples,and satisfactory recoveries were obtained（97.0-104.0%）.The results demonstrated that the modified HPC sensor has the advantages of simplicity,sensitivity,and practicality.