Preparation And Electrochemical Sensing Of Functional Carbon-based Composites

Owing to the advantages of high earth-abundance,high conductivity and thermal conductivity,chemical stability,large specific surface area,biocompatibility and easy functionalization,carbon-based materials have been widely used in environmental remediation and as electrochemical biosensors to diagnose some diseases.The composites of carbon-based materials with metal nanoparticles not only increase the effective active area of the material on the electrode,but also have a faster electron conduction rate,showing stronger catalytic,electrical conductivity and better quality transport.Based on these,the carbon-based composites modified by metal nanoparticles were constructed,and the electrochemical sensing properties of TNT and glucose related to human health were studied.The primary contents are as follows:（1）The porous 3D flower-like AgPtPd nanoparticles anchored on reduced graphene oxide（Ag Pt Pd NPs/r GO）have been developed as a novel material for high-performance electrochemical TNT detection by a wet-chemical reduction strategy.The results show that Ag Pt Pd NPs/r GO shows a wide linear range（0.1-8 ppm）and a low detection limit（0.95 ppb）for the electrochemical detection of TNT.The composite has high selectivity and good reproducibility for TNT determination.The remarkable features are probably attributed to the synergistic effect of the high electrocatalytic activity of Ag Pt Pd nanoparticles for TNT reduction,the large surface area of r GO and the excellent adsorption performance for TNT.（2）Cu-Cu₂O nanoparticles supported on carbon paper（Cu/Cu₂O-CP）were synthesized by electrodeposition method,and copper nanofiber grown on carbon fiber paper（Cu-CP）were generated by the calcination with melamine in nitrogen at high temperature.The two sensors were used for electrochemical determination of glucose.The sensor based on Cu/Cu₂O-CP composites shows remarkable electrocatalytic activity towards glucose oxidation comparing to the Cu-CP.This may be attributed to the nanostructured copper oxide（Cu₂O）and Cu composites,which promotes the redox reaction through the multiple valences and redox couples on the surface oxide layer,and the material with high electrical conductivity,large active area and abundant active sites.When used for glucose detection,the testing results show a good linear relationship from 0.05 to 3 m M with a detection limit of 0.038 m M and the sensitivity（S）of 3 m A m M^-1 cm^-2.Moreover,the sample has good anti-interference and stability.（3）Cu-Co based nanosheets modified on carbon paper（Cu/Co-NSs）were firstly synthesized by hydrothermal method.Then,Cu-Co based nitrogen-doped carbon nanotubes（Cu/Co-NCNTs）supported on carbon paper was successfully synthesized by calcination of melamine and Cu/Co-NSs in nitrogen.They are used in the electrochemical determination of glucose.The testing results show that the sensitivity（S）is 0.84 m A m M^-1 cm^-2 in the linear range of 0.05-5 m M and the limit of detection（LOD）is calculated to be as low as 18μM according to the signal-to-noise ratio of three（S/N=3）.Moreover,the composites show high selectivity and stability for the determination of glucose.The remarkable performance were probably ascribed to its unique structure,high electrocatalytic activity of multivalent Cu-Co based metal oxides for glucose oxidation,and significant synergistic effect of nitrogen-doped carbon.Additionally,the material has high electrical conductivity,large active area and abundant active sites,which further promoted the electrochemical determination of glucose.