Construction And Application Of Electrochemical Sensors Based On Graphene Composites

Electrochemical sensors show good accuracy and sensitivity,and have also been widely used in drug,food and environmental detection due to their advantages such as simple operation,low instrument cost and short response time.Graphene is a good material used in modified electrode for electrochemical sensor.Graphene is easily agglomerated and difficult to be dispersed in water or some organic solvents,and it limits the application range of graphene.Relatively speaking,graphene composite materials can make up for those shortcomings.These composite materials have the advantages of high catalytic activity,large specific surface area,strong adsorption performance and good biocompatibility.In this thesis,several different graphene composite materials were developed and used to construct electrochemical sensors.These sensors have helped realizing a series of application researches.The main works are expressed as follows:（1）Reduced graphene oxide loaded flower-like bismuth subcarbonate composite（Bi₂O₂CO₃-rGO）has been successfully synthesized by a facile hydrothermal method.The prepared Bi₂O₂CO₃-rGO was applied to construct a new voltammetric sensor（Bi₂O₂CO₃-rGO/GCE）,which was used for the determination of the active ingredient urapidil.Under optimum conditions,a lower detection limit(1.5×10^-9 mol L^-1)and wider linear range(5.0×10^-9 mol L^-1-4.0×10^-6 mol L^-1)were achieved by the proposed sensor.Finally,the proposed method was applied to the analysis of real sample,and the results showed applicablity and reliablity.（2）A new nanocomposite,molybdenum copper selenide（MoCuSe）nanoparticles decorated with reduced graphene oxide（rGO）,was successfully prepared by a facile hydrothermal method.The MoCuSe-rGO modified glassy carbon electrode（MoCuSe-rGO/GCE）was fabricated for the first time,which provided a large surface area and exhibited a rapid electron transport rate for the bisphenol A（BPA）.The electrochemical behavior of BPA was investigated with various techniques and a new electroanalytical method was established with differential pulse voltammetry.Under optimum conditions,the proposed sensor showed an excellent electrochemical response to BPA with detection limit of 9.0×10^-10 mol L^-1 and wider linear range of 3.0×10^-9 mol L^-1-1.0×10^-4 mol L^-1.Finally,the proposed method was successfully applied to determine BPA in real samples.（3）NiCoMnO₄ nanoparticles decorated reduced graphene oxide composite（NiCoMnO₄-rGO）has been successfully synthesized by a facile hydrothermal method and used as modification composite to construct a new voltammetric sensor（NiCoMnO₄-rGO/GCE）,which exhibited high electrochemical response to bisphenol AP（BPAP）.The electrochemical behavior of BPAP was studied by linear sweep voltammetry in detail.Under optimum conditions,the electrochemical response of designed sensor for BPAP had a good linear relationship in the range of 5.0×10^-9 mol L^-1-7.0×10^-6 mol L^-1 and a low detection limit of 1.5×10^-9 mol L^-1.The proposed method was successfully applied to the analysis of real sample with safactory results.