Preparation And Application Of Two Kinds Of MOFs Composite Modified Electrodes

In recent years,metal organic frameworks?MOFs?have been widely used in the fields of gas adsorption,separation and catalysis due to their porous properties,but the research on their electrochemical properties is still in its infancy.In this paper,we focus on the application of MOFs materials in the field of photoelectrochemical and electrochemical sensors.We prepared new photoelectrochemical and electrochemical sensors based on MOFs materials,and studied their photoelectrochemical and electrochemical properties.In the selection of MOFs materials,we chose two kinds of MOFs materials with more research:ZIF-8 and Ui O-66-NH₂.Using their porous properties or photoelectrochemical and electrical properties,different photoelectrochemical and electrochemical sensors were fabricated to realize the quantitative detection of chloride ions and carcinoembryonic antigen?CEA?.The main purpose of our research is to fully explore the advantages of MOFs materials and broaden the application field of MOFs materials.The contents and results of the study are as follows:?1?Silver nanoparticles?Ag NPs?were decorated into the cavities of ZIF-8 to fabricate a novel Ag NPs/ZIF-8 modified glassy carbon electrode?GCE?for electrochemical sensing of chloride ion.Benefiting from the synergistic properties of ZIF-8 and Ag NPs,the Ag NPs/ZIF-8/GCE showed favorable performance towards chloride ion.For comparison,the electrochemical activity of Ag NPs wrapped by ZIF-8?Ag NPs@ZIF-8?and Ag NPs coating on ZIF-8?Ag NPs-on-ZIF-8?were also investigated and it was found that Ag NPs/ZIF-8 possessed the best performance.Some experimental parameters including p H of the supporting electrolyte and scan rate were also investigated.Under optimal conditions,the proposed sensor exhibited excellent stability,reproducibility and selectivity for the determination of chloride ion with a wide linear detection range from 5 to 4000?mol dm^-3and a low detection limit of 0.61?mol dm^-3?S/N=3?.The proposed sensor was successfully applied to the determination of chloride ion spiked in human serum.?2?A label-free photoelectrochemical?PEC?immunosensor for the quantitative detection of carcinoembryonic antigen?CEA?was simply developed via drop-casting method and chemical bath deposition?CBD?approach.Under visible-light illumination,the resulting Ag₂S/Ui O-66?NH₂?/FTO electrode displayed high photocurrent intensity,attributed to the cascade band-edge between Ag₂S and Ui O-66?NH₂?,which not only facilitate the charge transfer but also effectively promote the separation of e^-/h⁺pairs.Moreover,the influence of the concentrations of Ui O-66?NH₂?,the thickness of Ag₂S,and the applied potential was also investigated.Under optimal conditions,the developed PEC immunosensor exhibited remarkable stability,reproducibility,and selectivity for the determination of CEA in a wide linear range from 1 pg m L^-1to 1?g m L^-1with a low detection limit of 0.9 pg m L^-1?S/N=3?.Besides,satisfactory results were obtained when the PEC immunosensor was applied to determine CEA in real human serum samples.