Study On Electrochemical Sensor Based On Layered Double Transition Metal Hydroxide

Layered doubled hydroxides(Layered doubled hydroxides,LDH)is a two-dimensional material with a layered structure formed by alternately stacking metal hydroxides with a regular octahedral structure.It is composed of positively charged metal hydroxide laminates,negatively charged interlayer anions and water molecules.It has the advantages of large specific surface area,adjustable metal,adjustable anion and open metal sites.It is used in electrocatalysis and energy Storage,electrochemical sensing and other fields have broad application prospects.However,due to the non-covalent interaction between the positively charged laminates and the anions between the layers,the LDH materials obtained by conventional preparation methods tend to accumulate easily,resulting in poor application performance.In this dissertation,the design idea of synthesizing single-layer LDH material and compounding with carbon material improves the accumulation of LDH material,and applies the obtained LDH material to the electrochemical sensing and detection of glucose and hydrogen peroxide(H₂O₂),used in real-time rapid monitoring of diabetic patients.The NiFe-FLDH(Formamide-LDH)with a single-layer dispersion structure of Ni and Fe is obtained by a simple co-precipitation method and the addition of a formamide inhibitor,and it is prepared by the urea synthesis method.The NiFe-ULDH(Urea-LDH)material was used for comparative study.The results show that the NiFe-FLDH material prepared by the co-precipitation method has a radial size of25 nm and a height of less than 1 nm.Compared with the NiFe-ULDH obtained by the urea synthesis method,the ultra-thin NiFe-FLDH material has a larger specific surface area,more active sites,better conductivity and ion adsorption/transport capabilities.The glucose sensor based on NiFe-FLDH material has good glucose detection ability,its linear range is 10-1680?M,the detection limit is as low as 5.84?M,and the sensitivity is as high as 3353.16?A·mM^-1·cm^-2.Through a simple hydrothermal reaction method,using 2-Methylimidazole(2-MIM)as a source of alkalinity on multi-walled carbon nanotubes(MWCNT),a network structure of MWCNT-CuAl-MLDH(Methylimidazole-LDH)was prepared,and compare it with MWCNT-CuAl-ULDH synthesized by urea synthesis method.The results show that the LDH in MWCNT-CuAl-MLDH is connected to MWCNT in a lamellar form.Compared with MWCNT-CuAl-ULDH,it has a larger specific surface area and low crystallinity,which makes MWCNT-CuAl-MLDH more exposed The active site has excellent electrical conductivity and charge transfer and H2O2 adsorption and diffusion capabilities.The H₂O₂sensor based on the MWCNT-CuAl-MLDH material has good H₂O₂detection ability,with a linear range of 0.1-20.8m M,a detection limit as low as 12?M,and the sensitivity is as high as 241.33?A·mM^-1·cm^-2.