Study Of Chemically Modified Electrode Based On Fe₃O₄@Poly-dopamine Nanomaterials

Dopamine(DA)is the main ingredient of the protein secreted by the foot antennae of marine organisms-mussel.In recent years,many studies found that dopamine can auto-polymerize to form a polydopamine(PDA)coating on almost all material surfaces in weak alkaline solution.Morever,PDA is abundant in catechol and N-H groups which can stir the second reaction and serve a platform for the second reaction of the materials.Currently,the electrochemical sensors fabricated by the self-polymerization of dopamine have become a hot research.In this article,using the properties of dopamine referred above,two magnetic nano-materials composites were synthesized.At the same time,two kinds of new electrochemical sensors were constructed based on the force between magnetic nano-material composites and the magnetic glassy carbon electrode.The fabricated sensors were used to detect H2O2 and hydrazine hydrate.The main contents are as follows:1.A facile and novel strategy was successfully explored for the synthesis of Au and silver nanoparticles-deposited polydopamine(PDA)-coated Fe3O4 nano-materials.Firstly,the surfaces of the particles were functionalized by polydopamine(PDA),and then gold and silver nanoparticles were plated on the Fe3O4@PDA surface by electroless plating with the help of complexing capacity of the amino groups and weak oxidation reduction ability of the phenolic hydroxyl groups.2.A H2O2 electrochemistry sensors was fabricated by droping the synthesized Fe3O4@PDA-Ag nano-composites on the magnetic glassy carbon electrode.Results showed that the fabricated electrode had good performances in H2O2 reduction,lowered the reduction potential and increased the peak current.Reduction peak current has good linership with the H2O2 concentration in appropriate concentration range.Overall,in this work we constructed a H2O2 sensor with good selectivity and sensitivity.3.Benefiting from the advantages of nano gold in electrochemical sensing,a hydrazine hydrate electrochemistry sensor was constructed by dropping the synthesized Fe3O4@PDA-Au nanomaterials on the magnetic glassy carbon electrode.The electrochemical behavior of hydrazine hydrate on the modified electrode was also investigated carefully.The results showed that the sensor had good electrocatalytic activity toward the oxidation of hydrazine in the neutral phosphate buffer solution(pH=7.0).Under the optimal conditions,the sensor exhibited a low detection limit,a wide linear range,and high sensitivity as well as good stability and repeatability.The sensor has been successfully applied to determine hydrazine in real samples with good accuracy and precision.