| Zinc-tin nanocomposites are the most typical materials in the semiconductor family.Due to their obvious characteristics in optics,electrochemistry,and physics,they can be applied to sensors,electrocatalysis,and supercapacitors.It is considered to be a potential material for making electrochemical sensors.Due to their different shapes and sizes,nanomaterials exhibit many excellent properties,typically including high catalytic activity,large specific surface area,strong adsorption and high surface activity.For nanomaterials,cubic zinc stannate as a micro-nano-semiconductor metal oxide has shown broad application prospects as electrocatalysts.As a new type of semiconductor electrocatalyst,zinc hydroxystannate(Zn Sn(OH)6)has a wide band gap and a large number of hydroxyl groups distributed on the surface,which can form hydroxyl radicals(·OH)during the electrocatalytic reaction.It can be used as the active center in the electrocatalytic reaction process to exhibit excellent electrocatalytic performance.As a metal-semiconductor oxide,zinc hydroxystannate can offer significant advantages for sensors by promoting an increase in free electron density.Multi-walled carbon nanotubes have a wider range of applications and can attract the focus of the research community;nano-tin sulfides,as transition metal sulfides,have attracted extensive attention due to their excellent physical and chemical properties,the integration and synergy of binary metal sulfides Increased selectivity and activity.Therefore,the synthesis of binary metal sulfides is considered to be the most simple and effective method to improve the performance of electrochemical sensors,catalysis and energy applications.Metal oxide nanoparticles have the characteristics of high free energy and large specific surface area.When the modified electrode is on the surface of the electrode,the sensitivity of the electrode can be significantly improved.By introducing the two-dimensional(2D)nanomaterial zinc oxide(Zn O)into the modified electrode,the catalytic effect of the sensor can be improved,and it can also be promising for rapid detection.Zinc oxide has high application value in the fabrication of high-performance electrochemical sensors due to its excellent physical and chemical properties resulting from its two-dimensional structure.Carbon material targets represented by graphene,carbon nanotubes,and carbon black have been widely used in the field of electrochemical detection of inorganic ions and biomolecules.Among the above materials,carbon nanotubes and carbon black have more obvious advantages,such as good electrical conductivity,low application cost,strong adsorption performance and large specific surface area,so they are widely used in electrochemical detection of various substances.favored by researchers.With the excellent conductivity of multi-walled carbon nanotubes,by modifying cubic zinc stannate,nano-tin sulfide,and nano-zinc oxide materials to synthesize nano-composite modified electrodes,the application range can be further expanded due to the synergistic effect,and can be greatly improved.To improve the electrochemical signal,then improve the sensitivity and reduce the detection limit.Therefore,this thesis is mainly devoted to the construction of the sensor based on Zn-Sn nanocomposite and its application in electrochemical analysis.The main content is divided into the following three parts:1.Preparation of Zn Sn(OH)6/MWCNTs modified electrode and its determination of L-tyrosineIn this work,a well-dispersed Zn Sn(OH)6/MWCNTs composite was successfully prepared and modified on the electrode surface,which can be used for electrochemical detection of L-tyrosine.The electrochemical behavior of the electrode was analyzed by cyclic voltammetry(CV)and electrochemical impedance spectroscopy(EIS).The experimental results showed that the modified electrode Zn Sn(OH)6/MWCNTs/GCE improved the oxidation peak current of L-tyrosine.Differential pulse voltammetry(DPV)was used to detect L-tyrosine.The results showed that in the concentration range of 2.5×10-6?1×10-3 mol·L-1,the peak current was linearly related to the concentration.The detection limit was 1×10-7 mol·L-1(S/N=3).This experiment shows that the Zn Sn(OH)6/MWCNTs composite has a good response to L-tyrosine,and good determination results are obtained.It can be applied to the detection of L-tyrosine in actual milk.2.Preparation of Sn S2/MWCNTs modified electrode and its determination of dopamineIn this work,the Sn S2/MWCNTs/GCE modified electrode can significantly enhance the redox peak current corresponding to dopamine(DA).The electrochemical behavior of the modified electrode was analyzed by differential pulse voltammetry(DPV)and other methods,and it was found that the modified electrode could exhibit an ideal electrochemical response to ascorbic acid.Under the optimal detection conditions,the detection linear range of dopamine is 2.5×10-8?1×10-3mol·L-1,and the detection limit is 2×10-8 mol·L-1(S/N=3).In addition,glucose,uric acid,hydrogen peroxide and other substances have no obvious interference in the detection of ascorbic acid,and can be used for the detection of dopamine in actual substances,and the detection results are relatively satisfactory.3.Preparation of Zn O/MWCNTs modified electrode and its determination of folic acidIn this work,MWCNT and Zn O nanocomposites were used to modify the electrode layer by layer and successfully used for electrochemical detection of folic acid.The performance of the electrodes was investigated by electrochemical methods such as CV and DPV.The experimental results show that the linear range of Zn O/MWCNTs/GCE electrode for the detection of folic acid is 5×10-8?1×10-3mol·L-1,and the detection limit is 3×10-8mol·L-1(S/N=3).The method is fast,simple and efficient,and good results have been achieved in the detection of folic acid in fruit juice. |
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