Synthesis Of Cu₂O NPs Catalysts For Fabrication Of E-DNA Sensors Based On CuAAC

The Cu(?)-catalyzed alkynyl-azide cycloaddition(Cu AAC)reaction is a"near-perfect"bonding reaction,and it has been widely used in chemistry,biology and materials science.In recent years,Cu(?)is used as an indispensable catalyst in the reaction,so researchers have developed a variety of Cu(?)species(homogeneous and heterogeneous)to catalyze the Cu AAC reaction,including Cu(?)/reducing agent,Cu(0)/oxidant,Cu(?)/auxiliary ligands and Cu(?)compounds.It is difficult to separate the Cu(?)catalyst from the final product in a homogeneous catalytic system,which results in economic and environmental problems and hinders its application.Therefore,it is particularly important to remove the catalyst from the final product.The heterogeneous catalyst has characteristics of easy recovery and reusability.The thesis aims to study the Cu(?)heterogeneous catalytic system.Researchers have been extensively focused on the Cu AAC catalyzing ability of Cu₂O due to its cheapness,availability,as well as its nature of being a transition metal oxide.However,Cu₂O nanomaterials are easily oxidized in the air,which decreases the catalytic activity of the catalyst.This thesis focuses on the synthesis of different Cu₂O nanomaterials to improve their stability and catalytic activity in Cu AAC reaction.The main research contents are as follows:g-C₃N₄Cu₂O composite materials were synthesized in order to enhance the stability of Cu₂O nanomaterials in the air.Two-dimensional nanomaterial g-C₃N₄with chemically stable is synthetized by a simple approach.Therefore,in the first part of this thesis,we choose g-C₃N₄as the load.Various amounts of cuprous oxide(Cu₂O)modified graphitic carbon nitride(g-C₃N₄)denoted as n%g-C₃N₄Cu₂O composites were successfully synthetized via a facile solvethermal method.In order to obtain the optimal conditions,different g-C₃N₄Cu₂O composites were synthetized by adjusting the amount of g-C₃N₄,the reaction time,the amount of surfactant PVP and the dosage of the particle growth inhibitor sodium citrate.The FTIR,SEM,TEM,XPS,XRD etc.characterizations revealed the chemical composition,bond structure and morphologies of as-synthesized n%g-C₃N₄Cu₂O composites.The results showed that composite materials with uniform particle size(30±5 nm)and good dispersion on g-C₃N₄were successfully synthesized.In the second part of this thesis,Cu₂O nanowires with high yield and easy recycling were synthesized.In order to obtain the optimal conditions,different Cu₂O nanowires were synthetized by adjusting experimental condition such as the reaction temperature,HAc concentration,surfactant PTCDA dosage.The FTIR,SEM,TEM,XPS,XRD etc.characterizations revealed the chemical composition,bond structure and morphologies of as-synthesized Cu₂O nanowires.Cu₂O nanowires with uniform linear morphology,uniform arrangement and 50±5nm diameter were successfully synthetized.The catalytic activity of as-synthesized g-C₃N₄Cu₂O composites and Cu₂O nanowires were estimated by fabricating electrochemical DNA sensors based on Cu AAC reaction.The ACV peak current and the electrochemical probe density(?*)were acquired by electrochemical measurements.The results indicated that5%g-C₃N₄Cu₂O composites kept high catalytic activity after 30 days.Similarly,the catalytic activities of Cu₂O nanowires under a variety of synthesis conditions were also compared by fabricating different electrochemical DNA sensors.The results showed that Cu₂O nanowires with optimal catalytic activity were synthetized under the condition containing 10 m M HAc,1.5 mg PTCDA,and the temperature of 180?.