Construction Of Functionalized Graphene Electrochemical Sensors And Their Application In Environmental Detection

Graphene is a single-atom-thick flat sheet with excellent optical,electrical and mechanical properties,and can be widely used to construct electrochemical sensors.Graphene oxide is an oxide of graphene,which has excellent physical,chemical,and electrical properties.By functionalizing its surface,more excellent materials can be obtained.Metal nanoparticles have large specific surface area,high conductivity,and good catalytic activity.Thus,the metal nanoparticles can be loaded on the surface of the functionalized graphene to form a graphene-based metal nanoparticle composite material,thereby improving the sensitivity and selectivity of the electrochemical sensor.In this paper,functionalized graphene materials were prepared by sulfonation and pyridine functional modification of graphene oxide,and then combined with tin and silver metal nanoparticles to construct three kinds of graphene-based composite modified electrochemical sensors.The main research contents of this paper are as follows:(1)Electrochemical sensor based on tin metal nanoparticles/sulfonated graphene(SnNPs/SGO)composite material and its research on paracetamol detectionIntroduce sulfonate on the surface of graphene oxide to obtain SGO.Combine the successfully prepared SGO graphene with SnNPs to obtain SnNPs/SGO composite materials.FT-IR,SEM and EDS were used to characterize the composite.The SnNPs/SGO aqueous solution was applied to the surface of the glassy carbon electrode(GCE)by a drop coating method,and a SnNPs/SGO/GCE sensor was constructed using cyclic voltammetry(CV),differential pulse voltammetry(DPV)and electrochemical impedance spectroscopy(EIS)studied the electrochemical behavior of paracetamol on the modified electrode.Within the concentration range of 0.20～500.00 μM,the peak current of paracetamol showed a good linear relationship with the detection limit was0.06 μM(S/N=3).(2)Electrochemical sensor based on silver metal nanoparticles/pyridine(AgNPs/Py-GO)composite material and its simultaneous detection of catechol and hydroquinoneThrough simple heat treatment of GO and pyridine,Py-GO was prepared,and AgNPs/Py-GO nanocomposites were prepared by combining successfully prepared Py-GO with AgNPs.The AgNPs/Py-GO aqueous solution was dispersed on the surface of the glassy carbon electrode by the drop coating method,and dried at room temperature.The AgNPs/Py-GO aqueous solution was dispersed on the surface of the glassy carbon electrode by the drop coating method,and dried at room temperature to prepare the AgNPs/Py-GO electrochemical sensor.The electrochemical behavior of catechol and hydroquinone on the above working electrode was studied.The results show that the sensor realizes hydroquinone and catechol For the simultaneous detection of hydroquinone,the linear range of catechol detection is 0.46～500.00 μM,the detection limit is 0.97 μM(S/N=3),and the linear detection range of hydroquinone is0.85～500.00 μM,the detection limit is 0.62 μM(S/N=3),which is used for the detection of hydroquinone and catechol in tap water and lake water,and the recovery rates are93.40%-101.70(4)and 91.90%-103.00%,the detection effect is good.(3)Electrochemical sensor based on tin metal nanoparticles/pyridine functionalized graphene(SnNPs/Py-GO)composite material and its simultaneous detection of nitrite and ascorbic acidSnNPs/Py-GO nanocomposites were obtained by loading tin metal nanoparticles on the surface of pyridine-functionalized graphene by hydrazine hydrate reduction method,and SnNPs/Py-GO sensors were obtained by modifying the glassy carbon electrode with its aqueous solution.The electrochemical performance of the sensor is studied,and the results show that the sensor has good reproducibility,stability,selectivity and electrocatalytic activity,and the separation of the electrooxidation peaks of nitrite and ascorbic acid is good,which can realize the sensitive detection of both at the same time.The linear response range and detection limit of nitrite are 0.40～150.00μM and 0.006 μM(S/N =3)respectively,and the response range and detection limit of ascorbic acid are 0.35～200.00 μM and 0.019 μM(S/N=3).