Preparation Of Polypyrrole Modified Hierarchically Nanoporous Carbon Materials And Application In Electrochemical Analysis Of Hydrogen Peroxide

Hydrogen peroxide(H₂O₂)has a widely application in many fields such as daily life,bioprocess,green energy chemistry,etc.However,high concentration of H₂O₂ not only can easily pollute the water and environment,but also can cause organism damage and even organism death.Therefore,the analysis of level concentration of H₂O₂ is of great practical significance.Recently,the electrochemical method for H₂O₂ detection has attracted much attention due to the advantages of low-cost and simple operation.Therefore,it is very important to construct H₂O₂ electrochemical sensor with high sensitivity,reproducibility and stability.The research center of H₂O₂electrochemical sensor is to develop the materials,which can be used to modify electrode.In various materials,hierarchically nanoporous carbon materials(HNCMs)possesses high specific surface area,good hydrothermal stability,rich pore structure,and good electrical conductivity.Secondly,palladium(Pd)nanoparticles are natural benign conductor materials with excellent electro-catalytic activity.Finally,polypyrrole(PPy)has strong mechanical properties,good stability,and strong electrical conductivity.Therefore,the synthesized HNCMs by dynamic template method is used to load Pd nanoparticles to obtain HNCMs-Pd,then the electrochemical sensor of PPy/HNCMs-Pd modified glassy carbon electrode(GCE)is constructed for H₂O₂ detection.The experimental results show that it has good selectivity,high sensitivity,good stability,anti-interference,and low detection limit.This thesis mainly includes the following two aspects:(1)Controllable synthesis,electrochemical properties and superelectric properties of hierarchically nanoporous carbon materials with different morphologyBy dynamic template method,using the mesocrystalline complex formed by anionic polyelectrolyte polyacrylic acid(PAA)and cationic surfactant cetylpyridinium monohydrate(CPC)as templates,silica formed by ethyl orthosilicate(TEOS)as the supporting framework,sucrose as carbon source to synthesize carbon materials.By adjusting the amount of PAA,four kinds of hierarchically nanoporous carbon materials(HNCMs)with clear shape,interconnected micropores,ordered mesopores and larger secondary nanopores were obtained,including submicrosphere(HNCMs-S),hexagonal nanoplates(HNCMs-N),dumbbell-like particles(HNCMs-D),and hexagonal microprism particles(HNCMs-P).The electrochemical properties of HNCMs as an electrode material were detected.The results showed that HNCMs-S base electrode has a maximum specific capacitance of 233.8 F g^-1 at a current density of 1 A g^-1 due to its large specific surface area and clear hierarchical nanoporous structure.HNCMs were successfully assembled into the symmetric capacitor devices(HNCMs-X//HNCMs-X),and the test of electrical properties showed that all four HNCMs materials have excellent capacitance properties,including high capacitance,high rate performance,low resistance,and excellent cycle stability.By comparison,the HNCMs-S//HNCMs-S supercapacitor has a superior specific capacitance of55.5 F g^-1 at a current density of 0.5 A g^-1,higher energy density(7.7 Wh kg^-1at 250 W kg^-1).(2)Construction of PPy-HNCMs-Pd modified electrode and their electrochemical analysis of H₂O₂In process of chemical reduction,HNCMs prepared by the"dynamic template"were used as a carrier to support noble metal palladium to obtain HNCMs-Pd catalyst.The catalytic material HNCMs-Pd were fully mixed with pyrrole(Py)monomer and were coated on the surface for glass carbon electrode(GCE),then the PPy-HNCMs-Pd modified electrode for hydrogen peroxide detection was constructed in the presence of Fe Cl₃solution as initiator.By optimizing the process conditions,(including the amount of Pd,electrolyte p H value,the ratio of HNCMs-Pd and Py,the concentration of Fe Cl₃,polymerization temperature,polymerization time,etc).The electrode sensor of 1-PPy/1-HNCMs-Pd/GCE was prepared by the optimal condition(the loading of the Palladium was 1 wt%,the p H value of the 0.1 M PBS was7.0,the mass ratio of catalytic material HNCMs-Pd to Py feed was 1:1,the molar ratio of Py to Fe Cl₃ was 1:2,the process of polymerization was conducted in ice water bath with 8 h),the detection limit of this electrode at low concentration of H₂O₂(range from 0.1 to10.0?M)is 0.087?M(S/N=3)with a sensitivity of 4182.86?A/m M·cm^-2.