In-situ Modification Of Graphite Electrode And Its Sensitive Properties

Electro-activation treated sheet graphite column electrodes（SGE）were loaded Cu-MOF,MnO₂ and NiCu-LDH sensitive materials by in-situ modification method.The morphology and composition of the electrodes were characterized by SEM,XRD and XPS.The sensing performance of the modified electrodes to nitrite and H2O₂ were tested by cyclic voltammetry and potentiostatic method.The detail results are as follows:Cu-MOF in situ modified sheet pencil graphite electrodes（SPGE）was prepared in methanol solution（abbreviation:Cu-MOF/SPGE）.The sensing performance of Cu-MOF/SPGE to nitrite was investigated.The experimental results show that Cu-MOF/SPGE has the strongest electrocatalytic activity for nitrite（pH=7,0.75 V）.The concentration range of nitrite could be detected from 2 to 2500 μM and the sensitivity is up to 0.12 μA ·μM-1·cm^-2.The modified electrode has good selectivity and stability.Nanosheet and nanowire MnO₂ in situ modified SGE were prepared by water bath method and hydrothermal method,respectively（abbreviation:s-MnO₂/SGE,w-MnO₂/SGE）.The sensing performances of these MnO₂/SGEs to H2O₂ were investigated.The experimental results show that the sensitivity of the s-MnO₂/SGE is 0.446 μA·μM-1·cm^-2 in H2O₂ concentration range of 5 μM～1500 mM.The concentration range of w-MnO₂/SGE for H2O₂ detection is 2 μM～8.0 mM,and the sensitivity is 0.16μA·μM-1·cm^-2.The above two modified electrodes have good selectivity and stability.NiCu-LDH,Ni（OH）₂ and Cu（OH）₂ in-situ modified SGE were prepared by hydrothermal method（abbreviation:NiCu-LDH/LDH,Ni（OH）₂/LDH,Cu（OH）₂/LDH）.The sensing performance of the three modified electrodes to H2O₂ was investigated.The experimental results show that under the optimal detection conditions（pH8 and potential-0.80 V）,the concentration of H2O₂ detected by NiCu-LDH/SGE ranges from 40 μM～80 mM with the sensitivity as 0.08 μA·μM-1·cm^-2,Ni（OH）₂/SGE can detect H2O₂ concentration from 40 μM～80 mM with sensitivity as 0.06 μA·M-1·cm^-2.Under the optimal detection conditions（pH7 and potential-0.75 V）,the concentration of H2O₂ detected by Cu（OH）₂/SGE ranges from 40 μM～1.2 mM with the sensitivity as 0.41μA·μM-1·cm^-2.Figure52;Table4;Reference76...