Research On Electrochemical Sensors Based On Carbon-based Composite Materials

At present,carbon-based materials,mainly graphyne,graphene,fullerene,nano-diamond and bio-carbon materials,are being explored more and more in electrochemistry,supercapacitors,and material catalysis.The main reason is that carbon materials have excellent physical properties,and good biocompatibility.The carbon material is used as the skeleton,through high-pressure hydrothermal,high-temperature calcination,electrostatic spinning and other technologies,the carbon-based composite material with large specific surface area and good electrical conductivity is prepared,which is more sensitive to sodium nitrite(Na NO₂)and hydrogen peroxide(H₂O₂),potassium bromate(KBr O₃)and luteolin for sensitive detection.In this paper,a series of materials have been prepared around the carbon base as the core.The thesis includes the following three parts:1.In this paper,nanodiamond(ND),electrochemically deposited gold nanoparticles(Au NPs),hemoglobin(Hb)and Nafion were modified on carbon ionic liquid electrodes(CILE)to prepare electrochemical biosensors(Nafion/Hb/Au NPs/ND/CILE).The morphology of ND and Au NPs were observed by scanning electron microscope(SEM),and the characterization results of ultraviolet-visible absorption spectroscopy(UV-Vis)and Fourier infrared transform spectroscopy(FT-IR)proved that Hb maintained its original protein structure and biology active.The presence of Au NPs and ND increased the effective surface area of electrode and accelerated electron transfer.Subsequently,the electrocatalytic reduction performance of the modified electrode on different substrates was explored,and the electrocatalytic reduction effect on trichloroacetic acid(TCA),sodium nitrite(Na NO₂),potassium bromate(KBr O₃)was excellent,The modified electrode has good reproducibility and stability,and could be used for the analysis of KBr O₃ content in seawater.2.Pt-Fe P-C catalyst was prepared by controlled etching and in-situ carbonization process when MOFs MIL-88A(Fe)was used as a template,it provided effective proton supply and accelerated electron transport.Pt-Fe P-C could provide effective proton supply and accelerate electron transport.Pt-Fe P-C,hemoglobin(Hb)and Nafion membrane were drip-coated on the prepared carbon ionic liquid electrode(CILE)to construct an enzyme sensing electrode.The morphology of Pt-Fe P-C was observed by scanning electron microscope(SEM)and transmission electron microscope(TEM),and structure and biological activity of Hb was proved by the characterization results of UV-Vis and FT-IR.Modified electrode had excellent catalytic performance for sodium nitrite(Na NO₂),hydrogen peroxide(H₂O₂),potassium bromate(KBr O₃),and trichloroacetic acid(TCA).The detection ranges are 0.20?7.00 mmol L^-1,0.30?7.00mmol L^-1,0.76?7.00 mmol L^-1,5.00?900 mmol L^-1,respectively,and the detection limit corresponds to 0.07 mmol L^-1,0.10 mmol L^-1,0.25 mmol L^-1,1.67 mmol L^-1.3.The petal-like Fe S@Mo S₂-C was synthesized on carbon fiber cloth(CFC)by hydrothermal method,and the material dispersed and hemoglobin(Hb)and Nafion on the prepared carbon ionic liquid electrode to construct(Nafion/Hb/Fe S@Mo S₂-C/CILE)electrode.The valence state and morphology of Fe S@Mo S₂-C were explored by SEM,TEM,XPS and other characterization methods.And through UV-Vis and FT-IR technology,it was found that Fe S@Mo S₂-C did not change the the biological activity of hemoglobin.The effective surface area of the electrode(0.920 cm²)and the electron transfer rate K_s(1.89 s^-1)were calculated using cyclic voltammetry.The modified electrode has excellent catalytic performance for sodium nitrite(Na NO₂),hydrogen peroxide(H₂O₂)and potassium bromate(KBr O₃),and the detection ranges were0.01?5.00 mmol L^-1,0.10?14.00 mmol L^-1,and 0.05?25.00 mmol L^-1,respectively.