CN-121994893-A - Solid contact layer of all-solid ion selective electrode, and preparation method and application thereof

CN121994893ACN 121994893 ACN121994893 ACN 121994893ACN-121994893-A

Abstract

The invention relates to the technical field of sensing for detecting ions in a culture water body, and discloses a solid contact layer of an all-solid ion selective electrode, which is prepared by synthesizing FeCoNi@ZIF-8 doped with three transition metals of iron, cobalt and nickel by a one-pot method, generating nano porous carbon based on ZIF-8 by pyrolysis, finally obtaining a transition metal doped ZIF-8 derived carbon nanomaterial, mixing the carbon nanomaterial with a hydrophobic material and an ionic liquid, and constructing the ion-electron conversion layer of the all-solid ion selective electrode with excellent hydrophobic performance. The solid contact layer prepared by the invention can not only effectively inhibit the formation of a water layer between the ion sensitive film and the conductive substrate and solve the potential drift problem of the ion selective electrode in measurement, but also improve the ion-electron transduction capability of the electrode under the combined action of the electric double-layer capacitance effect of the carbon nano material and the synergistic pseudo-capacitance effect between various transition metals.

Inventors

WANG CONG
FENG JINRU
WANG LIU
SUN LIANGYAN
LIN XIAOHAN
TIAN YUNING
WU SHUAI
LI DAOLIANG

Assignees

中国农业大学

Dates

Publication Date: 20260508
Application Date: 20260131

Claims (10)

1. The solid contact layer of the all-solid-state ion selective electrode is characterized in that transition metals Fe, co and Ni are doped in the process of preparing ZIF-8 by a one-pot method, and the transition metals Fe, co and Ni are grown at 0-5 ℃ to obtain FeCoNi@ZIF-8; the molar ratio of Fe, co and Ni to the ligand of the ZIF-8 is 0.006-0.007:0.006-0.007:0.015-0.02:1, and the mass ratio of FeCoNi@ZIF-8, hydrophobic material and ionic liquid is 6-8:1.7-2.2:0.7-1.2.
2. The solid state contact layer of all solid state ion selective electrode according to claim 1, wherein the hydrophobic material is polyvinylidene fluoride-hexafluoropropylene or polyvinylidene fluoride; the ionic liquid is 1-ethyl-3-methylimidazole bis (trifluoromethanesulfonyl) ammonium salt.
3. The solid state contact layer of an all solid state ion selective electrode according to claim 2, wherein the Fe is from FeSO 4 ·7H 2 O or Fe (NO 3 ） 2 ·6H 2 O; The Co is derived from Co (NO 3 ） 2 ·6H 2 O; The Ni is derived from Ni (NO 3 ） 2 ·6H 2 O).
4. A method of making a solid contact layer for an all-solid ion selective electrode according to claim 3, comprising the steps of: Dissolving FeSO 4 ·7H 2 O or Fe（NO 3 ） 2 ·6H 2 O、Co（NO 3 ） 2 ·6H 2 O、Ni（NO 3 ） 2 ·6H 2 O and zinc salt in an alcohol reagent to obtain a mixed solution A, dissolving 2-methylimidazole serving as an organic ligand in methanol to obtain a mixed solution B; Mixing the mixed solution A and the mixed solution B at 0-5 ℃ for reaction to obtain FeCoNi@ZIF-8; carrying out pyrolysis on FeCoNi@ZIF-8 under a protective atmosphere to obtain FeCoNi@ZIF-8-NPC; dissolving polyvinylidene fluoride-hexafluoropropylene in acetone, adding FeCoNi@ZIF-8-NPC for ultrasonic treatment, and adding ionic liquid for ultrasonic treatment to obtain dispersion liquid; And (3) coating the dispersion liquid on the electrode conductive substrate by adopting a liquid coating method to obtain the solid contact layer.
5. The method according to claim 4, wherein the pyrolysis temperature is 950 ℃ to 1050 ℃ and the pyrolysis time is 60min to 80min.
6. The method of claim 4, wherein the alcohol reagent is methanol.
7. The method according to claim 4, wherein the protective atmosphere is nitrogen.
8. Use of the solid contact layer of claim 3 for the preparation of an all-solid ion selective electrode, wherein the all-solid ion selective electrode consists of a conductive substrate, a solid contact layer, and a sensitive film; The conductive substrate is a rigid conductive substrate or a flexible conductive substrate; the solid contact layer is positioned between the ion sensitive membrane and the conductive substrate; the sensitive film is prepared from an ionophore, an ion exchanger, a polymer substrate material and a plasticizer.
9. Use of an all-solid-state ion-selective electrode according to claim 8 for detecting ion concentration in a water environment.
10. The use according to claim 9, wherein the adapted body of water environment is an aquaculture water body.

Description

Solid contact layer of all-solid ion selective electrode, and preparation method and application thereof Technical Field The invention relates to the field of all-solid-state ion selective electrodes, in particular to a solid-state contact layer of an all-solid-state ion selective electrode, and a preparation method and application thereof. Background The Ion Selective Electrode (ISE) can perform rapid and direct in-situ analysis, eliminates errors caused by sample preservation or storage and environmental condition change, has the advantages of easy miniaturization, low power consumption, rapid detection, low manufacturing cost and the like, and becomes the most attractive sensing platform for environmental water analysis. The solid contact ion selective electrode (SC-ISE) directly deposits the ISM on the surface of the solid electrode, and a solid contact layer (SC) is added between the ISM and the conductive substrate to serve as an ion-electron transduction layer to replace internal liquid filling, so that the ISM is directly deposited on the surface of the solid electrode, cumbersome liquid phase contact of the liquid contact ion selective electrode (LC-ISE) is eliminated, and the stability and reliability of the electrode are improved. In the use process of the solid ion selective electrode, a thin water layer formed at the interface of the solid contact layer and the ion selective membrane is a water layer, the water layer can cause potential drift and delay response, and as all ISMs can absorb water to a certain extent, the solid contact layer with hydrophobicity is critical in avoiding the formation and accumulation of the water layer. Graphene is of a single-layer hexagonal honeycomb structure, has excellent conductivity, large specific surface area and hydrophobicity, has an electric double layer capacitance when used as a solid contact layer, and has proved an important effect on the electrode in inhibiting the improvement of the water layer. The ultra-thin and defect-free graphene sheet can be produced by a hydrodynamic auxiliary layering technology, has high conductivity and uniform porosity, so that the effective surface area for forming an electric double layer is increased, the electric double layer is dripped on the surface of an electrode substrate to serve as a solid contact layer, the electric double layer capacitance is enhanced, the potential drift of an electrode under continuous operation and external interference is effectively reduced, the excellent chemical inertness and extremely low reactivity under environmental conditions are realized, the interference of oxygen, carbon dioxide and light is reduced to the greatest extent, and the electrode potential is further stabilized. In addition to direct drop coating, graphene can also be used for directly depositing graphene oxide (CRGO or ERGO) on the surface of an electrode in a chemical reduction mode, and in an inkjet printing mode, a laser induction mode and the like. In addition, graphene needs to be used in combination with other materials such as metal oxides, metal nanoparticles, and polymers to improve sensing performance, these compounds increase the cost, complexity, and manufacturing time of the sensor, and may reduce the flexibility and biocompatibility of the sensor, and graphene has a limited surface area and is easy to stack, and the sensitivity of the prepared ion-selective electrode still does not reach a desired level. Other carbon nanomaterials can also be used as a complement to graphene, such as carbon nanotubes, carbon black, 3DOM carbon, which have enabled sensors with low detection limits and excellent stability in a diverse and challenging real world environment. However, most of the carbon material surface reacts with water or oxygen, and additional functional groups may be introduced when preparing the electrode, resulting in additional drift, so that stability and anti-interference performance are affected. Disclosure of Invention In order to solve the problems, the invention provides a solid contact layer of an all-solid ion selective electrode, and a preparation method and application thereof. The invention provides a solid contact layer of an all-solid ion selective electrode, which is prepared by doping transition metals Fe, co and Ni in a one-pot method ZIF-8 process, and growing at 0-5 ℃ to obtain FeCoNi@ZIF-8; the molar ratio of Fe, co and Ni to the ligand of the ZIF-8 is 0.006-0.007:0.006-0.007:0.015-0.02:1, and the mass ratio of FeCoNi@ZIF-8, hydrophobic material and ionic liquid is 6-8:1.7-2.2:0.7-1.2. The transition metals Fe, co and Ni selected by the invention not only have good electron conductivity, but also have various oxidation states, can efficiently participate in the oxidation-reduction process through the available electrons, and are the main sources of oxidation-reduction capacitors (pseudocapacitors). In the transition metal, the cost of iron, cobalt and nickel is low, the electroch