Research On Solid-contact Lead Ion Selective Electrodes Based On Ti₃C₂ And Nb₂C With Different Morphologies

Solid contact ion-selective electrodes have the characteristics of easy preparation,easy miniaturization,and convenient detection,and are widely used in environmental testing.Due to the influence of the water layer,electric double layer and charge transfer impedance between the interface between the ion-selective sensitive membrane and the conductive substrate,the potential drift of the solid-contact ion-selective electrode will affect the potential test.If the solid contact layer is introduced between the ion-selective sensitive membrane and the conductive substrate,it is expected to greatly improve the potential stability.MXenes nanomaterials have properties such as high electrical conductivity and large specific surface area,and are widely used in sensing,and catalysis.In this study,Ti₃C₂ or Nb₂C in MXenes nanomaterials were used as a solid contact layer,an ion-selective sensitive membrane(Pb²⁺-ISM)was prepared with lead ionophore IV,and the two were drop-coated on a glassy carbon electrode（GC）to construct a new solid state Contacting lead ion selective electrode,using calomel electrode as reference electrode,constructing measurement battery,by measuring the electromotive force to detect lead ion concentration,focusing on the effect of different morphologies of carbides on potential drift,The main contents are as follows:（1）Multilayer Ti₃C₂ was successfully prepared by HF etching of ternary Ti₃Al C₂,and prepared a solid-contact lead ion selective electrode based on multilayer m-Ti₃C₂(Pb²⁺-ISM/m-Ti₃C₂/GC).In the range of10^-3-10^-7M,Pb²⁺-ISM/m-Ti₃C₂/GC has a stable potential response with a Nernst slope of 28.3 m V/decade and a detection limit of 6.3×10^-8 M.The introduction of multi-layer Ti₃C₂ as the transduction layer is beneficial to the ion-electron transduction process and helps to improve the long-term stability of the potential,but the potential cannot be quickly stabilized in a short time.The ion-electron transduction of Pb²⁺-ISM/m-Ti₃C₂/GC is based on the principle of electric double layer capacitance,and the correspondingtransductionmechanismisproposed.Pb²⁺-ISM/m-Ti₃C₂/GC was successfully used in the detection of spiked recovery of actual samples.（2）Using the method of dimethyl sulfoxide intercalation and ultrasonic peeling,few-layer Ti₃C₂ and single-layer Ti₃C₂ were successfully prepared.A new type of solid-contact lead Ion selective electrode based on Ti₃C₂ with different morphologies was prepared.In the range of 10^-3-10^-7 M,the electrode potential of Pb²⁺-ISM/f-Ti₃C₂/GC responds rapidly and is stable with the change of concentration,showing the best detection performance,and its Nernst slope is 24.3 m V/decade,the detection limit is 7.9×10^-8 M.Chronopotential and impedance tests show that the few-layer Ti₃C₂ as the transduction layer is most beneficial to the ion-electron transduction process and improves the potential stability.the ion-electron transduction of Ti₃C₂ is based on the principle of electric double layer capacitance,and proves that few-layer Ti₃C₂ has the largest electric double layer capacitance.The water layer test shows that a few layers of Ti₃C₂ can effectively eliminate the influence of the water layer in the electrode.It is proved that among the different morphologies of Ti₃C₂,few-layer Ti₃C₂ is the most suitable for solid transduction layer.Compared with multi-layer Ti₃C₂ and single-layer Ti₃C₂,few-layer Ti₃C₂ has smaller interface resistance and shorter ion diffusion path,so it is most conducive to the ion-electron transduction process in the solid-state ion-selective electrode transduction layer.Pb²⁺-ISM/f-Ti₃C₂/GC has the best electrode performance.（3）Multilayer Nb₂C,few-layer Nb₂C and single-layer Nb₂C were successfully prepared,and a new solid-contact lead ion selective electrode based on Nb₂C with different morphologies were prepared in this work.In the range of Pb（NO₃）₂ from 10^-3 to 10^-6 M,the electrode potential of Pb²⁺-ISM/f-Nb₂C/GC responds rapidly and stabilizes with the change of concentration,showing the best detection performance,and its Nernst slope was 29.9 m V/decade,the detection limit was 1.3×10^-6 M.Chronopotentiometry and impedance tests show that the few-layer Nb₂C as the transduction layer is most beneficial to the ion-electron transduction process and enhances the potential stability.Cyclic voltammetry tests proves that the ion-electron transduction of solid-contact lead ion selective electrodes based on Nb₂C with different morphologies is based on the principle of electric double layer capacitance,and proves that few-layer Nb₂C has the largest electric double layer capacitance.The water layer test shows that few-layer Nb₂C can effectively eliminate the influence of water layer in the electrode.The anti-interference test shows that the prepared solid contact electrodes based on Nb₂C with different morphologies have good anti-interference performance against light,CO₂ and O₂.It is proved that with different morphologies of Nb₂C,few-layer Nb₂C is most suitable for solid transduction layer.Compared with multi-layer Nb₂C and single-layer Nb₂C,few-layer Nb₂C has smaller interface resistance and shorter ion diffusion path,so it is most conducive to the ion-electron transduction process in the solid-state ion-selective electrode transduction layer.Pb²⁺-ISM/f-Nb₂C/GC has the best electrode performance.The morphology of Ti₃C₂ and Nb₂C were regulated by intercalation and ultrasonic exfoliation,which were used to construct a new solid contacting lead ion selective electrode.The experimental results show that few-layer MXenes have smaller interfacial resistance and shorter ion diffusion paths,which are most favorable for the ion-electron transduction process in the solid-state ion-selective electrode transduction layer.Among the two MXenes nanomaterials,Ti₃C₂ and Nb₂C,few-layer Ti₃C₂ is the most suitable material for the transduction layer of solid-contact lead-ion selective electrodes.The feasibility of using MXenes nanomaterials in the transduction layer of solid-contact ion-selective electrodes is demonstrated,which broadens the application of MXenes nanomaterials in the field of electrochemistry.In this paper,there are 42 pictures,10 tables,and 117 references...