Preparation Of Metal Nickel And Nickel Oxide Catalytic Materials And Supported By Graphene And Their Application In Glucose Detection

Rapid and accurate determination of blood glucose concentration is important for the diagnosis and treatment of diabetes.In addition,the detection of glucose also has important applications in bioengineering and food testing.Electrochemical glucose sensor has attracted wide attention because of its fast,accurate and efficient characteristics.Electrode material is the key factor to determine the performance of electrochemical detection of glucose.Non-noble metals and oxides nanomaterials as electrode materials provide a new direction for the development of non-enzymatic glucose electrochemical sensors.Transition metals and oxides nanomaterials are widely used in non-enzymatic glucose electrochemical sensors due to their low cost and excellent redox properties.Graphene,as a two-dimensional carbon nano-material,is an ideal carrier material for electroactive catalysts because of large specific surface area and great conductivity.In this paper,the precursor of nano-nickel oxide was prepared by hydrothermal method and liquid precipitation method,then nano-nickel oxide were obtained by high temperature heat treatment.The effects of preparation method,alkali source,solvent composition and dispersant on the structure and morphology and glucose detection performance of nickel oxide in hydrothermal process were investigated.Secondly,the graphene oxide was prepared by the modified Hummers method,then the graphene oxide was added to the hydrothermal kettle for preparing the precursor of nickel oxide before preparation,next the graphene-loaded nano-nickel oxide composite NiO/rGO was obtained by high temperature treatment.In addition,nano-nickel was prepared by liquid phase reduction method.The effect of solvent and reducing agent on the structure and morphology and glucose detection performance of nano-nickel electrode materials were investigated.Then,the reduced graphene oxide was added before preparation,the graphene-loaded nano-nickel composite Ni/rGO was prepared by liquid phase reduction method.XRD,SEM,FT-IR,CV and I-t were used to characterize the structure,composition,morphology and glucose detection performance of the above materials.The results are as follows:?1?NiO-urea-HT prepared by hydrothermal method with urea as an alkali source exhibits a morphology in which microparticles and nanofibers coexist,with a microparticle size below 100 nm and a nanofiber diameter of about 25 nm.NiO-urotropine-HT prepared with urotropine as an alkali source exhibits a nanosheet structure?sheet thickness is below 10 nm?,and these sheets are further disorderly stacked to form a superficially porous spherical structure with a diameter of 10?m.The nano-nickel oxide NiO-80%DMF-HT,NiO-50%DMF-HT and NiO-20%DMF-HT prepared by different solvent compositions in hydrothermal method all exhibited irregular spherical morphology with dimensions of 160,100 and 120 nm respectively.Nano-nickel oxide were prepared in the presence of a dispersant?sodium dodecyl sulfate SDS,polyvinylpyrrolidone PVP and polyethylene glycol PEG?,wherein NiO-SDS-HT and NiO/rGO composite both show 3D thin-walled porous structure,and the wall thickness is about 100 nm.In summary,nickel oxide and graphene-supported nickel oxide?NiO/rGO?prepared by hydrothermal preparation at 180?in the presence of urea as an alkali source and an SDS dispersant are 3D porous materials.?2?The electrochemical test results show that the 3D thin-walled porous nickel oxide NiO-SDS-HT prepared with nickel nitrate as the nickel source,urea as the alkali source,water as the solvent and SDS as the dispersing agent shows the best performance for glucose,and the sensitivity is 665.4?A·mM^-1·cm^-2,detection range is 0.004-4.27 mM,the limit of detection is 1.10?M.The detection performance of the composite NiO/rGO for glucose is further improved,the sensitivity is 983.5?A·mM^-1·cm^-2,the detection range is 0.004-6mM,and the limit of detection is 2.40?M.The large specific surface area and good electrical conductivity of graphene provide more reaction sites for the catalytic reaction.In addition,NiO/rGO composites show good anti-interference properties for ascorbic acid,uric acid and dopamine,and good selectivity for glucose.?3?The nickel electrode material prepared by a liquid phase reduction method,the nano-Ni-Et-N₂H₄-4?200 nm diameter sphere?prepared with ethanol as solvent has smaller size than Ni-H₂O-N₂H₄-4?agglomerated microspheres with diameter of 2?m?prepared with water as solvent.With the increase of hydrazine hydrate content from 4 mL to 12 mL,the morphology of nickle changes from smooth spheres to rough spheres,and nanoscale disordered porous three-dimensional lamellar structure was formed finally.In addition,the Ni/rGO composites prepared by adding graphene support exhibited disordered porous morphology.?4?The electrochemical tests showed that the three-dimensional nickel nanosheet prepared with ethanol as solvent and hydrazine hydrate as 12 mL show the best detection performance for glucose.The Sensitivity is 791.4?A·mM^-1·cm^-2 in the range of 0.01-1.10 mM and 387.8?A·mM^-1·cm^-2 in the range of 1.10-4.40 mM,and the limit of detection limit is 2.52?M;The sensitivity of the composite Ni/rGO for glucose detection is 1129.2?A·mM^-1·cm^-2 in the range of 0.004-1.87 mM and 660.6?A·mM^-1·cm^-2 in the range of 1.87-3.37 mM.The limit of detection is 4.44?M.In addition,the composite Ni/rGO exhibits good selectivity for glucose and good anti-interference properties for other substances such as dopamine,ascorbic acid and uric acid.