Preparation Of Several Kinds Of Carbon-based Composites And Studies On Their Electrocatalytic Performances

In recent years,carbon-based composites have been uesd as the electrode modified materials due to their many superior properties.In this paper,four kinds of composites based on carbon materials,metal and metal oxides materials were prepared,then used for electrode modified materials in fields of the detection and electrocatalysis toward small molecules.This work not only broadens the scope of application of carbon-based composites in electrochemistry,but also enriches the research contents of electrochemical sensors and eletrocatalysis.The full text was as follows:1.The carbon quantumdots/cuprous oxide（CQDs/Cu₂O）composite has been synthesized by a facile method with ultrasonic treatment and was characterized by scanning electron microscopy（SEM）,fourier transform infrared spectroscopy（FT-IR）and UV-visible spectroscopy（UV-vis）.Above CQDs/Cu₂ O composite was used for modifying carbon paste electrode（CPE）,and non-enzymatic hydrogen peroxide（H2O2）sensor was designed based on the obtained CQDs/Cu₂O-CPE,which showed a linear response range from 1.0 to 3397 μM and a detection limit of 0.33 μM towards the determination of H2O2.2.Urchin-like NiCo₂O₄ hollow composite was synthsized by facil solvothermal method,and then three kinds of NiCo₂O₄-C/C composites in diferent mass ratio were furtherly prepared by ultrasonic method based on carbon/carbon composites（C/C）and NiCo₂O₄.Their physicochemical properties were also characterized.Subsequently,NiCo₂O₄ and NiCo₂O₄-C/C were dispersed in perfluorosulfonic acid solution（Nafion）to modify glassy carbon electrode（GCE）,respectively.The results of electrochemical experiments showed that NiCo₂O₄-NF-GCE exhibited better nonenzymatic catalyzing activity for the oxidation of glucose than NiCo₂O₄-C/C-GCE,a wide linear range（5.0 – 175500 μM）and a low detection limit（1.7 μM）were achieved;the electrocatalytic performance to the methanol oxidation reaction（MOR）is better when the mass ratio of NiCo₂O₄ and C/C is 1:1.In addition,three kinds of palladium-carbon/carbon（Pd-C/C）composites with different content of Pd were prepared by solvothermal method as multifunctional electrocatalysts for MOR and formic acid oxidation reaction（FAOR）.The resultsing Pd-C/C-2（wt%,25%）composites exhibited good catalytic activity toward both MOR and FAOR.The apparent activation energy（Ea）of Pd-C/C-2 for MOR and FAOR were 8.77 and 15.31 kJ/mol,respectively,which was significantly lower than the vaule of commercial Pd/C.3.Ni/NiO/C composites derived from Ni-based metal organic frameworks（Ni-BTC）were synthesized via solvothermal reaction and subsequent thermal annealing（successively in nitrogen and air atmosphere）.Then,Ni/NiO/C composite was mixed with ionic liquid（IL）to modify CPE and the modified electrode was used for the immobilization of Myoglobin（Mb）/Hemoglobin（Hb）toward the detection of nitrite（NO₂^-）.Among them,the Mb/Ni/NiO/C/IL-CPE showed a wider linear range from 4 to 40892 μM with a lower detection limit of 1.3 μM.