Anion-selective electrode, method for its production and use

Abstract

This invention discloses an anion-selective electrode, its preparation method, and its application. The anion-selective electrode consists of two electrodes with different loading amounts, each on a conductive substrate loaded with a metal / a sparingly soluble metal salt. The preparation method involves first depositing a large amount of metal on a conductive substrate, then using it as the anode and electrolyzing it for a long time in an anion solution containing anions capable of forming the sparingly soluble metal salt, resulting in an electrode composed of a large amount of metal and its sparingly soluble salt. Then, a small amount of metal is deposited on another conductive substrate, which is then used as the anode and electrolyzed for a short time in the same anion solution, resulting in an electrode composed of a small amount of metal and its sparingly soluble salt. The two electrodes form an electrode pair. The selective electrode of this invention consists of a pair of electrodes, exhibiting uniform size, high specific surface area, and abundant active sites. Compared with traditional electrodes, it is smaller in size. The preparation method is simple and reliable. When applied to fields such as anion detection, it demonstrates high selectivity and sensitivity, making it suitable for widespread application.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical sensors, specifically relating to an anion-selective electrode, its preparation method, and its application. Background Technology

[0002] Anion detection is increasingly attracting attention, as anion imbalance often has negative consequences. Ion imbalances in the natural environment lead to pollution, while imbalances in the human body can cause disease. Anion detection has important applications in environmental monitoring and drug analysis. Therefore, the qualitative and quantitative detection of these ions has always been a key research focus. Quantitative anion analysis methods include ion chromatography and ion-selective electrodes.

[0003] Ion chromatography (such as a method for simultaneous detection of 11 common substances in water using ion chromatography [P] patent CN113406221B, 2021.05.27) can separate and detect ions, but the equipment used is expensive, the operation requirements are high, and the time consumption is long. To solve these problems, ion selective electrodes have become the focus of attention and have been widely developed and utilized.

[0004] Traditional anion-selective electrodes include crystal membrane electrodes and fluidized carrier membrane electrodes (liquid membrane electrodes). MRGanjali, M. Tahami, et al. proposed a bromide liquid membrane electrode in Analytical Letters, using bis(4-hydroxyphenyl)1,4-diaza-1,3-butadiene-Hg(II) complex as the electroactive material, PVC membrane and potassium bromide as internal reference solutions, and silver / silver chloride electrode as internal reference electrode (MRGanjali, M. Tahami, T. Poursaberi, ARPazoukian, M. Javanbakht, M. Shamsipur, et al. Analytical Letters 2003 Vol. 36 Issue 2 Pages 347-360). JLCarey, A. Hirao, K. Sugiyama et al. proposed a membrane electrode using a semi-fluorinated polymer as the ion-selective electrode membrane matrix (JLCarey, A. Hirao, K. Sugiyama and P. Bühlmann, Electroanalysis 2017 Vol.29 Issue 3 Pages 739-747). Qin Wei and Wang Xuewei proposed a liquid membrane electrode sensitive to organoboronic acid compounds, which requires an embedded sensitive membrane that is immiscible with water and doped with organoboronic acid compound acceptors (Patent No. CN104422722B). These electrodes often need to be applied to liquid interface systems based on ion exchange membranes. Because an internal reference solution needs to be filled inside the electrode and a reference electrode needs to be built in, this traditional electrode has certain limitations in miniaturization and integration (Liao.C, Zhong.L, Tang.Y, Membranes, 2021, 11, 959), and cannot be made into a flexible sensor. Summary of the Invention

[0005] This invention aims to overcome the functional limitations of traditional anion-selective electrode structures and to provide a solid-contact ion-selective electrode, its preparation method, and its application.

[0006] This invention is achieved through the following technical solution:

[0007] An anion-selective electrode is characterized by comprising a high-load electrode and a low-load electrode, both of which are electrodes composed of a metal / metal sparingly soluble salt loaded on a conductive substrate, wherein the loading amount of the metal / metal sparingly soluble salt on the high-load electrode is greater than that on the low-load electrode; wherein the metal / metal sparingly soluble salt has a structure in which metal particles are coated with metal particles.

[0008] In the above technical solution, the conductive substrate material is any one or more of the following: laser-etched PI film, graphite, graphene, glassy carbon, inert metal, or semiconductor material; the inert metal is platinum, gold, or titanium; and the semiconductor material is a silicon wafer.

[0009] A method for preparing an anion-selective electrode includes the following steps:

[0010] (I) Preparation of a conductive substrate loaded with a large amount of target metal element

[0011] The conductive substrate was placed in a solution containing the target metal ions for long-term deposition. After deposition, the conductive substrate was removed, cleaned, and dried to obtain a conductive substrate loaded with a large amount of the target metal element.

[0012] (II) Fabrication of high-loading electrodes

[0013] The conductive substrate loaded with a large amount of target metal element obtained in step (I) is used as the anode. Electrolysis is carried out in an anionic solution containing anion that can form a sparingly soluble salt with the target metal ions. After electrolysis, the substrate is taken out, cleaned, and dried to obtain an electrode composed of the target metal and its sparingly soluble salt, which is used as a high loading electrode.

[0014] (III) Preparation of a conductive substrate loaded with a small amount of the target metal element

[0015] The conductive substrate was placed in the same solution containing the target metal ions as in step (I) for short-term deposition. After deposition, the conductive substrate was removed, cleaned, and dried to obtain a conductive substrate loaded with a small amount of the target metal element.

[0016] (IV) Fabrication of low-load electrodes

[0017] The conductive substrate loaded with a small amount of the target metal element obtained in step (III) is used as the anode. Electrolysis is carried out in an anionic solution containing anion that can form a sparingly soluble salt with the target metal ions. After electrolysis, the substrate is taken out, cleaned, and dried to obtain an electrode composed of the target metal and its sparingly soluble salt, which is used as a low-load electrode.

[0018] In the above technical solution, the duration of long-term deposition in step (I) is longer than the duration of short-term deposition in step (III); the duration of long-term deposition in step (I) is 2000s to 6000s, preferably 2400s to 3600s; the duration of short-term deposition in step (III) is 25s to 1600s, preferably 25s to 600s.

[0019] In the above technical solution, the electrodeposition method is electrochemical deposition, magnetron sputtering, or evaporation.

[0020] In the above technical solution, the electrolysis method is electrochemical deposition, the electrochemical deposition is constant current electrodeposition, and the current density of the constant current electrodeposition is 1 mA·cm⁻¹. -2 ~15mA·cm -2 Preferably 3mA·cm -2 ~10mA·cm -2 .

[0021] In the above technical solution, the concentration of the metal ion in the solution containing the target metal ion is 0.02-0.1M; the solution containing the target metal ion is a silver nitrate solution or a lead nitrate solution.

[0022] In the above technical solution, the anionic solution that can form a sparingly soluble salt with the target metal ion is a solution containing any one or more of chloride ions, bromide ions, iodide ions, sulfide ions or sulfate ions, and the concentration range of the anion in the anionic solution is 0.1 to 2.5 M.

[0023] In the above technical solution, the electrode composed of the target metal and its sparingly soluble salt is an Ag / AgCl electrode, an Ag / AgBr electrode, an Ag / Ag2S electrode, an Ag / AgI electrode, or an Ag / Ag2SO4 electrode.

[0024] An application of an anion-selective electrode for the selective determination of anion involves forming an electrode pair with a high-load electrode and a low-load electrode, which are placed in an anion solution containing anion capable of forming a sparingly soluble salt with the target metal ion. Within a certain concentration range, the open-circuit potential between the two electrodes exhibits a linear relationship with the logarithm of the anion concentration, thus enabling the selective determination of anion. The concentration range is 85.0 μM to 300 mM.

[0025] The beneficial effects of this invention are:

[0026] This invention provides a solid contact ion-selective electrode with a simple structure. The electrode is based on a metal / metal sparingly soluble salt structure, where the metal sparingly soluble salt and the solution can directly exchange the anions that make up the sparingly soluble salt. The electrode can produce a specific response to the anions that make up the sparingly soluble salt, which can meet the requirements of in-situ ion analysis in solution. Attached Figure Description

[0027] Figure 1 This is the X-ray diffraction pattern of Ag / AgCl obtained in Example 1 of the present invention;

[0028] Figure 2 These are scanning electron microscope (SEM) images of Ag / AgCl obtained in Example 1 of this invention (the left image is an SEM image of a small amount of Ag / AgCl, and the right image is an SEM image of a large amount of Ag / AgCl).

[0029] Figure 3The left side shows the potential response curves of the chloride ion selective electrode obtained in Example 1 of the present invention when 5 μM, 10 μM, 20 μM...50 mM chloride ion solutions were continuously injected into PBS buffer solution with pH 7.4 at open circuit potential. The right side shows the linear fitting graph of the obtained response potential and the corresponding logarithmic value of chloride ion concentration.

[0030] Figure 4 This is a scanning electron microscope image of Ag / AgBr obtained in Example 6 of the present invention;

[0031] Figure 5 The left side shows the potential response curves of the bromide ion selective electrode obtained in Example 6 of the present invention when 5 μM, 10 μM, 20 μM...20 mM bromide ion solutions were continuously injected into PBS buffer solution with pH 7.4 at open circuit potential. The right side shows the linear fitting graph of the obtained response potential and the corresponding logarithmic value of bromide ion concentration.

[0032] Figure 6 This is a scanning electron microscope image of Ag / AgI obtained in Example 11 of the present invention;

[0033] Figure 7 The potential response curves of the iodide ion selective electrode obtained in Example 11 of the present invention are obtained when 5 μM, 10 μM, 20 μM...5 mM iodide ion solutions are continuously injected into PBS buffer solution with pH 7.4 at open circuit potential.

[0034] Figure 8 This is a scanning electron microscope image of Ag / Ag2S obtained in Example 17 of the present invention;

[0035] Figure 9 The potential response curves of the sulfide ion selective electrode obtained in Example 17 of this invention are obtained when 5 μM, 10 μM...50 μM sulfide ion solutions are continuously injected into a PBS buffer solution with a pH of 7.4 at an open circuit potential.

[0036] For those skilled in the art, other related figures can be obtained from the above figures without any creative effort. Detailed Implementation

[0037] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0038] In the following embodiments, the cleaning process, laser engraving process, and sealing process all use the same process, specifically:

[0039] In the following embodiments, the cleaning steps are as follows: a PI film of appropriate size is ultrasonically cleaned with ethanol and distilled water for 10 minutes each, and then dried with nitrogen gas.

[0040] The method for preparing graphene conductive substrate by laser engraving of PI film is as follows: First, place the cleaned PI film under the laser engraving head and engrave the designed electrode pattern for 6 minutes with a power of 5W to 15W.

[0041] Apply silver paste to the connection points for sealing; after drying, cover the electrode and the connection points with insulating glue; after the insulating glue dries, soak it in an ethanol solution (distilled water and ethanol volume ratio = 1:1) for 10 minutes, then rinse and dry to obtain a flexible graphene conductive substrate.

[0042] Example 1

[0043] A chloride ion selective electrode is prepared by the following steps:

[0044] (I) The graphene conductive substrate material was placed in a mixed solution containing silver nitrate and sodium nitrate, wherein the concentration of silver nitrate was 0.05M and the concentration of sodium nitrate was 0.1M; a magnetic wave was added, and the rotation speed was 400 rpm. The solution was then subjected to a 5 mA / cm² flow rate at room temperature. 2 A constant current electrodeposition was performed at a current density for 30 seconds. The conductive substrate material was then removed, cleaned, and dried to obtain a conductive substrate material loaded with a small amount of elemental silver.

[0045] (II) The obtained conductive substrate material loaded with a small amount of elemental silver was used as the anode and placed in 2M hydrochloric acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and a 5 mA / cm² flow rate was applied at room temperature. 2 A constant current electrodeposition was performed at a current density for 600 s to obtain a conductive material loaded with a small amount of Ag / AgCl, which was used as electrode I.

[0046] (III) The conductive substrate material is placed in the solution described in step 1) for electrodeposition for 2400s, the conductive substrate material is taken out, cleaned, and dried to obtain a conductive substrate material loaded with a large amount of silver.

[0047] (IV) Using the conductive substrate material loaded with a large amount of elemental silver obtained in step (III) as the anode, place it in 2M hydrochloric acid; add a magnetic stir bar, rotate at 400 rpm, and apply 5 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 2400 s. After removal, the material was cleaned and dried to obtain a conductive material loaded with a large amount of Ag / AgCl, which was used as electrode II.

[0048] Figure 1 The X-ray diffraction pattern of Ag / AgCl obtained in this embodiment shows that, in addition to the diffraction peaks of AgCl, there are also diffraction peaks of elemental silver, indicating that Ag was partially oxidized to AgCl, and the composition of the resulting product is Ag / AgCl.

[0049] Figure 2The scanning electron microscope image of Ag / AgCl obtained in this embodiment shows that during the conversion to silver chloride, the morphology of silver changes from a regular geometric shape to an irregular structure of multiple small spheres clustered together. Based on this, it can be inferred that in the electrochemical reaction, elemental silver loses electrons, and the generated silver ions combine with ionized chloride ions in the solution. The formed silver chloride is randomly attached to the surface of the original silver particles, resulting in the generation of an irregular morphology.

[0050] Figure 3 The left side shows the potential response curves of the chloride ion selective electrode obtained in Example 1 of this invention, under open-circuit potential, as 5 μM, 10 μM, 20 μM...50 mM chloride ion solutions were continuously injected into PBS buffer solution with a pH of 7.4. The right side shows the linear fitting graph of the obtained response potential and the corresponding logarithmic value of chloride ion concentration. It can be seen that the electrode has a detection range of 0.085 mM to 258.885 mM, high sensitivity, wide detection limit, fast response, and good linear fitting effect, which is close to the Nernst equation.

[0051] Example 2

[0052] A chloride ion selective electrode is prepared by the following steps:

[0053] (I) The graphene conductive substrate material was placed in a mixed solution containing silver nitrate and sodium nitrate, wherein the concentration of silver nitrate was 0.05M and the concentration of sodium nitrate was 0.1M; a magnetic wave was added, and the rotation speed was 400 rpm. The solution was then subjected to a 3 mA / cm² flow rate at room temperature. 2 A constant current electrodeposition was performed at a current density for 30 seconds. The conductive substrate material was then removed, cleaned, and dried to obtain a conductive material loaded with a small amount of elemental silver.

[0054] (II) The obtained conductive substrate material loaded with a small amount of elemental silver was used as the anode and placed in 2M hydrochloric acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was applied at room temperature with a current of 3 mA / cm. 2 A constant current electrodeposition was performed at a current density for 400 s to obtain a conductive material loaded with a small amount of Ag / AgCl, which was used as electrode I.

[0055] (III) The conductive substrate material is placed in the solution described in step 1) for electrodeposition for 2400s, the conductive substrate material is taken out, cleaned, and dried to obtain a conductive substrate material loaded with a large amount of silver.

[0056] (IV) Using the conductive substrate material loaded with a large amount of elemental silver obtained in step (III) as the anode, place it in 2M hydrochloric acid; add a magnetic stir bar, rotate at 400 rpm, and apply 3 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 2400 s. After removal, the material was cleaned and dried to obtain a conductive material loaded with a large amount of Ag / AgCl, which was used as electrode II.

[0057] Example 3

[0058] A chloride ion selective electrode is prepared by the following steps:

[0059] (I) Carbon was placed in a mixed solution containing silver nitrate and sodium nitrate, wherein the concentration of silver nitrate was 0.05 M and the concentration of sodium nitrate was 0.1 M; a magnetic stir bar was added, the rotation speed was 400 rpm, and the solution was heated at room temperature with 5 mA / cm 2 A constant current electrodeposition was performed at a current density for 25 seconds. The conductive substrate material was then removed, cleaned, and dried to obtain a conductive material loaded with a small amount of elemental silver.

[0060] (II) The obtained conductive substrate material loaded with a small amount of elemental silver was used as the anode and placed in 2M hydrochloric acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and a 5 mA / cm² flow rate was applied at room temperature. 2 A constant current electrodeposition was performed at a current density for 400 s to obtain a conductive material loaded with a small amount of Ag / AgCl, which was used as electrode I.

[0061] (III) The conductive substrate material is placed in the solution described in step 1) for electrodeposition for 2400s, the conductive substrate material is taken out, cleaned, and dried to obtain a conductive substrate material loaded with a large amount of silver.

[0062] (IV) Using the conductive substrate material loaded with a large amount of elemental silver obtained in step (III) as the anode, place it in 2M hydrochloric acid; add a magnetic stir bar, rotate at 400 rpm, and apply 5 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 2400 s. After removal, the material was cleaned and dried to obtain a conductive material loaded with a large amount of Ag / AgCl, which was used as electrode II.

[0063] Example 4

[0064] A chloride ion selective electrode is prepared by the following steps:

[0065] (I) Carbon was placed in a mixed solution containing silver nitrate and sodium nitrate, wherein the concentration of silver nitrate was 0.05 M and the concentration of sodium nitrate was 0.1 M; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was heated at room temperature using 3 mA / cm 2 A constant current electrodeposition was performed at a current density for 25 seconds. The conductive substrate material was then removed, cleaned, and dried to obtain a conductive material loaded with a small amount of elemental silver.

[0066] (II) The obtained conductive substrate material loaded with a small amount of elemental silver was used as the anode and placed in 2M hydrochloric acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was applied at room temperature with a current of 3 mA / cm. 2 A constant current electrodeposition was performed at a current density for 400 s to obtain a conductive material loaded with a small amount of Ag / AgCl, which was used as electrode I.

[0067] (III) The conductive substrate material is placed in the solution described in step 1) for electrodeposition for 2400s, the conductive substrate material is taken out, cleaned, and dried to obtain a conductive substrate material loaded with a large amount of silver.

[0068] (IV) Using the conductive substrate material loaded with a large amount of elemental silver obtained in step (III) as the anode, place it in 2M hydrochloric acid; add a magnetic stir bar, rotate at 400 rpm, and apply 5 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 2400 s. After removal, the material was cleaned and dried to obtain a conductive material loaded with a large amount of Ag / AgCl, which was used as electrode II.

[0069] Example 5

[0070] A chloride ion selective electrode is prepared by the following steps:

[0071] (I) The graphene conductive substrate material was placed in a mixed solution containing silver nitrate and sodium nitrate, wherein the concentration of silver nitrate was 0.05M and the concentration of sodium nitrate was 0.1M; a magnetic wave was added, and the rotation speed was 300 rpm. The solution was then subjected to a 5 mA / cm² flow rate at room temperature. 2 A constant current electrodeposition was performed at a current density for 30 seconds. The conductive substrate material was then removed, cleaned, and dried to obtain a conductive material loaded with a small amount of elemental silver.

[0072] (II) The obtained conductive substrate material loaded with a small amount of elemental silver was used as the anode and placed in 2M hydrochloric acid; a magnetic stirrer was added, the rotation speed was 300 rpm, and a 5 mA / cm² voltage was applied at room temperature. 2 A constant current electrodeposition was performed at a current density for 600 s to obtain a conductive material loaded with a small amount of Ag / AgCl, which was used as electrode I.

[0073] (III) The conductive substrate material is placed in the solution described in step 1) for electrodeposition for 2400s, the conductive substrate material is taken out, cleaned, and dried to obtain a conductive substrate material loaded with a large amount of silver.

[0074] (IV) Using the conductive substrate material loaded with a large amount of elemental silver obtained in step (III) as the anode, place it in 2M hydrochloric acid; add a magnetic stir bar, rotate at 300 rpm, and apply 5 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 2400 s. After removal, the material was cleaned and dried to obtain a conductive material loaded with a large amount of Ag / AgCl, which was used as electrode II.

[0075] Example 6

[0076] A bromide ion selective electrode is prepared by the following steps:

[0077] (I) The graphene conductive substrate material was placed in a mixed solution containing silver nitrate and sodium nitrate, wherein the concentration of silver nitrate was 0.05M and the concentration of sodium nitrate was 0.1M; a magnetic wave was added, and the rotation speed was 400 rpm. The solution was then subjected to a 5 mA / cm² flow rate at room temperature. 2 A constant current electrodeposition was performed at a current density for 30 seconds. The conductive substrate material was then removed, cleaned, and dried to obtain a conductive material loaded with a small amount of elemental silver.

[0078] (II) The obtained conductive substrate material loaded with a small amount of elemental silver was used as the anode and placed in 0.5M hydrobromic acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was tested at room temperature using 5 mA / cm². 2 A constant current electrodeposition was performed at a current density for 600 s to obtain a conductive material loaded with a small amount of Ag / AgBr, which was used as electrode I.

[0079] (III) The conductive substrate material is placed in the solution described in step 1) for electrodeposition for 2400s, the conductive substrate material is taken out, cleaned, and dried to obtain a conductive substrate material loaded with a large amount of silver.

[0080] (IV) The conductive substrate material loaded with a large amount of elemental silver obtained in step (III) was used as the anode and placed in 0.5M hydrobromic acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was subjected to 5 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 2400 s. After removal, cleaning and drying were carried out to obtain a conductive material loaded with a large amount of Ag / AgBr, which was used as electrode II.

[0081] Figure 4 The scanning electron microscope images of the large amount of Ag / AgBr obtained in Example 6 of this invention show that during the conversion to silver bromide, the morphology of silver changes from a regular geometric shape to an irregular structure of multiple small spheres clustered together. Based on this, it can be inferred that in the electrochemical reaction, elemental silver loses electrons, and the generated silver ions combine with ionized bromide ions in the solution. The resulting silver bromide is randomly attached to the surface of the original silver particles, thus leading to the generation of an irregular morphology.

[0082] Figure 5 The left side shows the potential response curves of the bromide ion selective electrode obtained in Example 6 of this invention, when continuously injected with 5 μM, 10 μM, 20 μM...20 mM bromide ion solutions into a PBS buffer solution with a pH of 7.4 at open-circuit potential. The right side shows the linear fitting graph of the obtained response potential and the corresponding logarithmic value of the bromide ion concentration. It can be seen that the electrode has a detection range of 0.085 mM to 292.218 mM, high sensitivity, wide detection limit, fast response, and good linear fitting effect, which is close to the Nernst equation.

[0083] Example 7

[0084] A bromide ion selective electrode is prepared by the following steps:

[0085] (I) The graphene conductive substrate material was placed in a mixed solution containing silver nitrate and sodium nitrate, wherein the concentration of silver nitrate was 0.05M and the concentration of sodium nitrate was 0.1M; a magnetic wave was added, and the rotation speed was 400 rpm. The solution was then subjected to a 5 mA / cm² flow rate at room temperature. 2 A constant current electrodeposition was performed at a current density for 25 seconds. The conductive substrate material was then removed, cleaned, and dried to obtain a conductive material loaded with a small amount of elemental silver.

[0086] (II) The obtained conductive substrate material loaded with a small amount of elemental silver was used as the anode and placed in 0.5M hydrobromic acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was tested at room temperature using 5 mA / cm². 2 A constant current electrodeposition was performed at a current density for 400 s to obtain a conductive material loaded with a small amount of Ag / AgBr, which was used as electrode I.

[0087] (IV) The conductive substrate material is placed in the solution described in step 1) for electrodeposition for 2400s. The conductive substrate material is then removed, cleaned, and dried to obtain a conductive substrate material loaded with a large amount of elemental silver.

[0088] (IV) The conductive substrate material loaded with a large amount of elemental silver obtained in step (III) was used as the anode and placed in 0.5M hydrobromic acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was subjected to 5 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 2400 s. After removal, cleaning and drying were carried out to obtain a conductive material loaded with a large amount of Ag / AgBr, which was used as electrode II.

[0089] Example 8

[0090] A bromide ion selective electrode is prepared by the following steps:

[0091] (I) The graphene conductive substrate material was placed in a mixed solution containing silver nitrate and sodium nitrate, wherein the concentration of silver nitrate was 0.05M and the concentration of sodium nitrate was 0.1M; a magnetic wave was added, and the rotation speed was 400 rpm. The solution was then subjected to a 5 mA / cm² flow rate at room temperature. 2 A constant current electrodeposition was performed at a current density for 25 seconds. The conductive substrate material was then removed, cleaned, and dried to obtain a conductive material loaded with a small amount of elemental silver.

[0092] (II) The obtained conductive substrate material loaded with a small amount of elemental silver was used as the anode and placed in 0.7M hydrobromic acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was tested at room temperature using 5 mA / cm². 2 A constant current electrodeposition was performed at a current density for 400 s to obtain a conductive material loaded with a small amount of Ag / AgBr, which was used as electrode I.

[0093] (III) The conductive substrate material is placed in the solution described in step (I) for electrodeposition for 2400s. The conductive substrate material is then removed, cleaned, and dried to obtain a conductive substrate material loaded with a large amount of elemental silver.

[0094] (IV) The conductive substrate material loaded with a large amount of elemental silver obtained in step (III) was used as the anode and placed in 0.7M hydrobromic acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was subjected to 5 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 2400 s. After removal, cleaning and drying were carried out to obtain a conductive material loaded with a large amount of Ag / AgBr, which was used as electrode II.

[0095] Example 9

[0096] A bromide ion selective electrode is prepared by the following steps:

[0097] (I) Place the graphite sheet in a mixed solution containing silver nitrate and sodium nitrate, wherein the concentration of silver nitrate is 0.05M and the concentration of sodium nitrate is 0.1M; add a magnetic stir bar, rotate at 400 rpm, and use 3 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 25 seconds. The conductive substrate material was then removed, cleaned, and dried to obtain a conductive material loaded with a small amount of elemental silver.

[0098] (II) The obtained conductive substrate material loaded with a small amount of elemental silver was used as the anode and placed in 0.7M hydrobromic acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was tested at room temperature using 3 mA / cm². 2 A constant current electrodeposition was performed at a current density for 400 s to obtain a conductive material loaded with a small amount of Ag / AgBr, which was used as electrode I.

[0099] (III) The conductive substrate material is placed in the solution described in step (I) for electrodeposition for 2400s. The conductive substrate material is then removed, cleaned, and dried to obtain a conductive substrate material loaded with a large amount of elemental silver.

[0100] (IV) The conductive substrate material loaded with a large amount of elemental silver obtained in step (III) was used as the anode and placed in 0.7M hydrobromic acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was subjected to 5 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 2400 s. After removal, cleaning and drying were carried out to obtain a conductive material loaded with a large amount of Ag / AgBr, which was used as electrode II.

[0101] Example 10

[0102] A bromide ion selective electrode is prepared by the following steps:

[0103] (I) The graphene conductive substrate material was placed in a mixed solution containing silver nitrate and sodium nitrate, wherein the concentration of silver nitrate was 0.05M and the concentration of sodium nitrate was 0.1M; a magnetic wave was added, and the rotation speed was 400 rpm. The solution was then subjected to a 3 mA / cm² flow rate at room temperature. 2 A constant current electrodeposition was performed at a current density for 30 seconds. The conductive substrate material was then removed, cleaned, and dried to obtain a conductive material loaded with a small amount of elemental silver.

[0104] (II) The obtained conductive substrate material loaded with a small amount of elemental silver was used as the anode and placed in 0.5M hydrobromic acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was tested at room temperature using 5 mA / cm². 2 A constant current electrodeposition was performed at a current density for 600 s to obtain a conductive material loaded with a small amount of Ag / AgBr, which was used as electrode I.

[0105] (III) The conductive substrate material is placed in the solution described in step (I) for electrodeposition for 2400s. The conductive substrate material is then removed, cleaned, and dried to obtain a conductive substrate material loaded with a large amount of elemental silver.

[0106] (IV) The conductive substrate material loaded with a large amount of elemental silver obtained in step (III) was used as the anode and placed in 0.5M hydrobromic acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was subjected to 5 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 2400 s. After removal, cleaning and drying were carried out to obtain a conductive material loaded with a large amount of Ag / AgBr, which was used as electrode II.

[0107] Example 11

[0108] An iodide ion-selective electrode is prepared by the following steps:

[0109] (I) The graphene conductive substrate material was placed in a mixed solution containing silver nitrate and sodium nitrate, wherein the concentration of silver nitrate was 0.05M and the concentration of sodium nitrate was 0.1M; a magnetic wave was added, and the rotation speed was 400 rpm. The solution was then subjected to a 5 mA / cm² flow rate at room temperature. 2 A constant current electrodeposition was performed at a current density for 25 seconds. The conductive substrate material was then removed, cleaned, and dried to obtain a conductive material loaded with a small amount of elemental silver.

[0110] (II) The obtained conductive substrate material loaded with a small amount of elemental silver was used as the anode and placed in 0.5M hydroiodic acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was tested at room temperature with 5 mA / cm 2 A constant current electrodeposition was performed at a current density for 400 s to obtain a conductive material loaded with a small amount of Ag / AgI, which was used as electrode I.

[0111] (III) The conductive substrate material is placed in the solution described in step (I) for electrodeposition for 2400s. The conductive substrate material is then removed, cleaned, and dried to obtain a conductive substrate material loaded with a large amount of elemental silver.

[0112] (IV) The conductive substrate material loaded with a large amount of elemental silver obtained in step (III) was used as the anode and placed in 0.5M hydrobromic acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was subjected to 5 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 2400 s. After removal, cleaning and drying were carried out to obtain a conductive material loaded with a large amount of Ag / AgI, which was used as electrode II.

[0113] Figure 6 The scanning electron microscope images of the large amount of Ag / AgI obtained in Example 11 of this invention show that during the conversion to silver iodide, the morphology of silver changes from a regular geometric shape to an irregular structure of multiple small spheres clustered together. Based on this, it can be inferred that in the electrochemical reaction, elemental silver loses electrons, and the generated silver ions combine with ionized iodide ions in the solution. The formed silver iodide is randomly attached to the surface of the original silver particles, resulting in the generation of an irregular morphology.

[0114] Figure 7 The image shows the potential response curves of the iodide ion selective electrode obtained in Example 11 of this invention, under open-circuit potential, after continuous injection of 5 μM, 10 μM, 20 μM...5 mM iodide ion solutions into a PBS buffer solution with a pH of 7.4. It can be seen that the electrode exhibits a detection range of 0.085 mM to 248.885 mM, high sensitivity, wide detection limit, fast response, and good linear fitting effect, closely approximating the Nernst equation.

[0115] Example 12

[0116] An iodide ion-selective electrode is prepared by the following steps:

[0117] (I) The graphene conductive substrate material was placed in a mixed solution containing silver nitrate and sodium nitrate, wherein the concentration of silver nitrate was 0.05M and the concentration of sodium nitrate was 0.1M; a magnetic wave was added, and the rotation speed was 300 rpm. The solution was then subjected to a 5 mA / cm² flow rate at room temperature. 2 A constant current electrodeposition was performed at a current density for 25 seconds. The conductive substrate material was then removed, cleaned, and dried to obtain a conductive material loaded with a small amount of elemental silver.

[0118] (II) The obtained conductive substrate material loaded with a small amount of elemental silver was used as the anode and placed in 0.5M hydroiodic acid; a magnetic stirrer was added, the rotation speed was 300 rpm, and the solution was tested at room temperature using 5 mA / cm². 2 A constant current electrodeposition was performed at a current density for 400 s to obtain a conductive material loaded with a small amount of Ag / AgI, which was used as electrode I.

[0119] (III) The conductive substrate material is placed in the solution described in step (I) for electrodeposition for 2400s. The conductive substrate material is then removed, cleaned, and dried to obtain a conductive substrate material loaded with a large amount of elemental silver.

[0120] (IV) The conductive substrate material loaded with a large amount of elemental silver obtained in step (III) was used as the anode and placed in 0.5M hydrobromic acid; a magnetic stirrer was added, the rotation speed was 300 rpm, and the solution was subjected to 5 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 2400 s. After removal, cleaning and drying were carried out to obtain a conductive material loaded with a large amount of Ag / AgI, which was used as electrode II.

[0121] Example 13

[0122] An iodide ion-selective electrode is prepared by the following steps:

[0123] (I) The graphene conductive substrate material was placed in a mixed solution containing silver nitrate and sodium nitrate, wherein the concentration of silver nitrate was 0.05M and the concentration of sodium nitrate was 0.1M; a magnetic wave was added, and the rotation speed was 400 rpm. The solution was then subjected to a 3 mA / cm² flow rate at room temperature. 2 A constant current electrodeposition was performed at a current density for 30 seconds. The conductive substrate material was then removed, cleaned, and dried to obtain a conductive material loaded with a small amount of elemental silver.

[0124] (II) The obtained conductive substrate material loaded with a small amount of elemental silver was used as the anode and placed in 0.5M hydroiodic acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was tested at room temperature using 3 mA / cm². 2 A constant current electrodeposition was performed at a current density for 600 s to obtain a conductive material loaded with a small amount of Ag / AgI, which was used as electrode I.

[0125] (III) The conductive substrate material is placed in the solution described in step (I) for electrodeposition for 2400s. The conductive substrate material is then removed, cleaned, and dried to obtain a conductive substrate material loaded with a large amount of elemental silver.

[0126] (IV) The conductive substrate material loaded with a large amount of elemental silver obtained in step (III) was used as the anode and placed in 0.5M hydrobromic acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was subjected to 3 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 2400 s. After removal, cleaning and drying were carried out to obtain a conductive material loaded with a large amount of Ag / AgI, which was used as electrode II.

[0127] Example 14

[0128] An iodide ion-selective electrode is prepared by the following steps:

[0129] (I) The graphene conductive substrate material was placed in a mixed solution containing silver nitrate and sodium nitrate, wherein the concentration of silver nitrate was 0.05M and the concentration of sodium nitrate was 0.1M; a magnetic wave was added, and the rotation speed was 400 rpm. The solution was then subjected to a 5 mA / cm² flow rate at room temperature. 2 A constant current electrodeposition was performed at a current density for 30 seconds. The conductive substrate material was then removed, cleaned, and dried to obtain a conductive material loaded with a small amount of elemental silver.

[0130] (II) The obtained conductive substrate material loaded with a small amount of elemental silver was used as the anode and placed in 0.5M hydroiodic acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was tested at room temperature with 5 mA / cm 2 A constant current electrodeposition was performed at a current density for 600 s to obtain a conductive material loaded with a small amount of Ag / AgI, which was used as electrode I.

[0131] (III) The conductive substrate material is placed in the solution described in step (I) for electrodeposition for 2400s. The conductive substrate material is then removed, cleaned, and dried to obtain a conductive substrate material loaded with a large amount of elemental silver.

[0132] (IV) The conductive substrate material loaded with a large amount of elemental silver obtained in step (III) was used as the anode and placed in 0.5M hydrobromic acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was subjected to 5 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 2400 s. After removal, cleaning and drying were carried out to obtain a conductive material loaded with a large amount of Ag / AgI, which was used as electrode II.

[0133] Example 15

[0134] An iodide ion-selective electrode is prepared by the following steps:

[0135] (I) The graphene conductive substrate material was placed in a mixed solution containing silver nitrate and sodium nitrate, wherein the concentration of silver nitrate was 0.05M and the concentration of sodium nitrate was 0.1M; a magnetic wave was added, and the rotation speed was 400 rpm. The solution was then subjected to a 3 mA / cm² flow rate at room temperature. 2 A constant current electrodeposition was performed at a current density for 30 seconds. The conductive substrate material was then removed, cleaned, and dried to obtain a conductive material loaded with a small amount of elemental silver.

[0136] (II) The obtained conductive substrate material loaded with a small amount of elemental silver was used as the anode and placed in 0.7M hydroiodic acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was tested at room temperature using 3 mA / cm². 2 A constant current electrodeposition was performed at a current density for 400 s to obtain a conductive material loaded with a small amount of Ag / AgI, which was used as electrode I.

[0137] (III) The conductive substrate material is placed in the solution described in step (I) for electrodeposition for 2400s. The conductive substrate material is then removed, cleaned, and dried to obtain a conductive substrate material loaded with a large amount of elemental silver.

[0138] (IV) The conductive substrate material loaded with a large amount of elemental silver obtained in step (III) was used as the anode and placed in 0.7M hydrobromic acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was subjected to 3 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 2400 s. After removal, cleaning and drying were carried out to obtain a conductive material loaded with a large amount of Ag / AgI, which was used as electrode II.

[0139] Example 16

[0140] An iodide ion-selective electrode is prepared by the following steps:

[0141] (I) The graphene conductive substrate material was placed in a mixed solution containing silver nitrate and sodium nitrate, wherein the concentration of silver nitrate was 0.05M and the concentration of sodium nitrate was 0.1M; a magnetic wave was added, and the rotation speed was 400 rpm. The solution was then subjected to a 5 mA / cm² flow rate at room temperature. 2 A constant current electrodeposition was performed at a current density for 30 seconds. The conductive substrate material was then removed, cleaned, and dried to obtain a conductive material loaded with a small amount of elemental silver.

[0142] (II) The obtained conductive substrate material loaded with a small amount of elemental silver was used as the anode and placed in 0.7M hydroiodic acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was tested at room temperature using 5 mA / cm². 2 A constant current electrodeposition was performed at a current density for 600 s to obtain a conductive material loaded with a small amount of Ag / AgI, which was used as electrode I.

[0143] (III) The conductive substrate material is placed in the solution described in step (I) for electrodeposition for 2400s. The conductive substrate material is then removed, cleaned, and dried to obtain a conductive substrate material loaded with a large amount of elemental silver.

[0144] (IV) The conductive substrate material loaded with a large amount of elemental silver obtained in step (III) was used as the anode and placed in 0.7M hydrobromic acid; a magnetic stirrer was added, the rotation speed was 400 rpm, and the solution was subjected to 5 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 2400 s. After removal, cleaning and drying were carried out to obtain a conductive material loaded with a large amount of Ag / AgI, which was used as electrode II.

[0145] Example 17

[0146] A sulfide ion selective electrode is prepared by the following steps:

[0147] (I) The graphene conductive substrate material was placed in a mixed solution containing silver nitrate and sodium nitrate, wherein the concentration of silver nitrate was 0.05M and the concentration of sodium nitrate was 0.1M; a magnetic wave was added, and the rotation speed was 400 rpm. The solution was then subjected to a 5 mA / cm² flow rate at room temperature. 2 A constant current electrodeposition was performed at a current density for 25 seconds. The conductive substrate material was then removed, cleaned, and dried to obtain a conductive material loaded with a small amount of elemental silver.

[0148] (II) The obtained conductive substrate material loaded with a small amount of elemental silver was used as the anode and placed in a solution of 0.2 mM Na2S. x In the solution; add a magnetic wave, rotate at 400 rpm, and use 5 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 400 s to obtain a conductive material loaded with a small amount of Ag / Ag2S, which served as the first electrode.

[0149] (III) The conductive substrate material is placed in the solution described in step (I) for electrodeposition for 2400s. The conductive substrate material is then removed, cleaned, and dried to obtain a conductive substrate material loaded with a large amount of elemental silver.

[0150] (IV) Using the conductive substrate material loaded with a large amount of elemental silver obtained in step (III) as the anode, place it in Na2S x In the solution; add a magnetic wave, rotate at 400 rpm, and use 5 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 2400 s. After removal, the material was cleaned and dried to obtain a conductive material loaded with a large amount of Ag / Ag2S, which was used as the second electrode.

[0151] Figure 8 The scanning electron microscope images of the large amount of Ag / Ag2S obtained in Example 17 of this invention show that during the conversion to silver sulfide, the morphology of silver changes from a regular geometric shape to an irregular structure of multiple small spheres clustered together. Based on this, it can be inferred that in the electrochemical reaction, elemental silver loses electrons, and the generated silver ions combine with ionized sulfur ions in the solution, forming silver sulfide that is randomly attached to the surface of the original silver particles, thus resulting in the generation of an irregular morphology.

[0152] Figure 9 The image shows the potential response curves of the sulfide ion selective electrode obtained in Example 17 of this invention, obtained by continuously injecting 5 μM, 10 μM...50 μM sulfide ion solutions into a PBS buffer solution with pH 7.4 at open-circuit potential. It can be seen that the electrode exhibits high sensitivity, a wide detection limit, fast response, and good linear fitting, closely approximating the Nernst equation, within a detection range of 0.085 mM to 82.218 mM.

[0153] Example 18

[0154] A sulfide ion selective electrode is prepared by the following steps:

[0155] (I) The graphene conductive substrate material was placed in a mixed solution containing silver nitrate and sodium nitrate, wherein the concentration of silver nitrate was 0.05M and the concentration of sodium nitrate was 0.1M; a magnetic wave was added, and the rotation speed was 400 rpm. The solution was then subjected to a 3 mA / cm² flow rate at room temperature. 2 A constant current electrodeposition was performed at a current density for 30 seconds. The conductive substrate material was then removed, cleaned, and dried to obtain a conductive material loaded with a small amount of elemental silver.

[0156] (II) The obtained conductive substrate material loaded with a small amount of elemental silver was used as the anode and placed in a solution of 0.2 mM Na2S. x In the solution; add a magnetic wave, rotate at 400 rpm, and use 3 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 600 s to obtain a conductive material loaded with a small amount of Ag / Ag2S, which was used as electrode I.

[0157] (III) The conductive substrate material is placed in the solution described in step (I) for electrodeposition for 2400s. The conductive substrate material is then removed, cleaned, and dried to obtain a conductive substrate material loaded with a large amount of elemental silver.

[0158] (IV) Using the conductive substrate material loaded with a large amount of elemental silver obtained in step (III) as the anode, place it in Na2S x In the solution; add a magnetic wave, rotate at 400 rpm, and use 3 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 2400 s. After removal, the material was cleaned and dried to obtain a conductive material loaded with a large amount of Ag / Ag2S, which was used as electrode II.

[0159] Example 19

[0160] A sulfide ion selective electrode is prepared by the following steps:

[0161] (I) The graphene conductive substrate material was placed in a mixed solution containing silver nitrate and sodium nitrate, wherein the concentration of silver nitrate was 0.05M and the concentration of sodium nitrate was 0.1M; a magnetic wave was added, and the rotation speed was 400 rpm. The solution was then subjected to a 3 mA / cm² flow rate at room temperature. 2 A constant current electrodeposition was performed at a current density for 25 seconds. The conductive substrate material was then removed, cleaned, and dried to obtain a conductive material loaded with a small amount of elemental silver.

[0162] (II) The obtained conductive substrate material loaded with a small amount of elemental silver was used as the anode and placed in a solution of 0.2 mM Na2S. x In the solution; add a magnetic wave, rotate at 400 rpm, and use 3 mA / cm at room temperature. 2A constant current electrodeposition was performed at a current density for 400 s to obtain a conductive material loaded with a small amount of Ag / Ag2S, which was used as electrode I.

[0163] (III) The conductive substrate material is placed in the solution described in step 1) for electrodeposition for 2400s, the conductive substrate material is taken out, cleaned, and dried to obtain a conductive substrate material loaded with a large amount of silver.

[0164] (IV) Using the conductive substrate material loaded with a large amount of elemental silver obtained in step (III) as the anode, place it in Na2S x In the solution; add a magnetic wave, rotate at 400 rpm, and use 3 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 2400 s. After removal, the material was cleaned and dried to obtain a conductive material loaded with a large amount of Ag / Ag2S, which was used as electrode II.

[0165] Example 20

[0166] A sulfide ion selective electrode is prepared by the following steps:

[0167] (I) The graphene conductive substrate material was placed in a mixed solution containing silver nitrate and sodium nitrate, wherein the concentration of silver nitrate was 0.05M and the concentration of sodium nitrate was 0.1M; a magnetic wave was added, and the rotation speed was 400 rpm. The solution was then subjected to a 5 mA / cm² flow rate at room temperature. 2 A constant current electrodeposition was performed at a current density for 25 seconds. The conductive substrate material was then removed, cleaned, and dried to obtain a conductive material loaded with a small amount of elemental silver.

[0168] (II) The obtained conductive substrate material loaded with a small amount of elemental silver was used as the anode and placed in a solution of 0.2 mM Na2S. x In the solution; add a magnetic wave, rotate at 400 rpm, and use 5 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 400 s to obtain a conductive material loaded with a small amount of Ag / Ag2S, which was used as electrode I.

[0169] (III) The conductive substrate material is placed in the solution described in step (I) for electrodeposition for 2400s. The conductive substrate material is then removed, cleaned, and dried to obtain a conductive substrate material loaded with a large amount of elemental silver.

[0170] (IV) Using the conductive substrate material loaded with a large amount of elemental silver obtained in step (III) as the anode, place it in Na2S x In the solution; add a magnetic wave, rotate at 400 rpm, and use 5 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 2400 s. After removal, the material was cleaned and dried to obtain a conductive material loaded with a large amount of Ag / Ag2S, which was used as electrode II.

[0171] Example 21

[0172] A sulfide ion selective electrode is prepared by the following steps:

[0173] (I) The graphene conductive substrate material was placed in a mixed solution containing silver nitrate and sodium nitrate, wherein the concentration of silver nitrate was 0.05M and the concentration of sodium nitrate was 0.1M; a magnetic wave was added, and the rotation speed was 400 rpm. The solution was then subjected to a 5 mA / cm² flow rate at room temperature. 2 A constant current electrodeposition was performed at a current density for 25 seconds. The conductive substrate material was then removed, cleaned, and dried to obtain a conductive material loaded with a small amount of elemental silver.

[0174] (II) The obtained conductive substrate material loaded with a small amount of elemental silver was used as the anode and placed in a solution of 0.2 mM Na2S. x In the solution; add a magnetic wave, rotate at 400 rpm, and use 5 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 600 s to obtain a conductive material loaded with a small amount of Ag / Ag2S, which was used as electrode I.

[0175] (III) The conductive substrate material is placed in the solution described in step (I) for electrodeposition for 2400s. The conductive substrate material is then removed, cleaned, and dried to obtain a conductive substrate material loaded with a large amount of elemental silver.

[0176] (IV) Using the conductive substrate material loaded with a large amount of elemental silver obtained in step (III) as the anode, place it in Na2S x In the solution; add a magnetic wave, rotate at 400 rpm, and use 5 mA / cm at room temperature. 2 A constant current electrodeposition was performed at a current density for 2400 s. After removal, the material was cleaned and dried to obtain a conductive material loaded with a large amount of Ag / Ag2S, which was used as electrode II.

[0177] Working principle of the invention:

[0178] This invention employs deposition and electrodeposition methods, controlling the preparation conditions to prepare the target metal and its sparingly soluble salt, and loads them onto a conductive substrate. Using this method, two electrodes with significantly different metal / corresponding sparingly soluble salt loadings are prepared to form an electrode pair. According to the Nernst equation, the potential is related to the ion activity in the solution. By successively adding the analyte ion to the substrate solution to change the ion activity, the corresponding potential response can be obtained. The combined effect of these characteristics results in an anion-selective electrode exhibiting excellent response performance, high sensitivity, and a wide detection limit.

[0179] This invention employs a simple deposition and electrolysis method to enable target metals and sparingly soluble metal salts to autonomously load onto a prepared conductive substrate. The invention regulates the growth patterns of Ag / AgCl, Ag / AgBr, Ag / AgI, and Ag / Ag2S by controlling the concentration ratio of target metal ions (silver ions, lead ions) and the solution of the anion to be tested, as well as the electrodeposition time and current density. If the deposition time is too long, the electrodeposited material, such as Ag / AgCl, will grow out of the substrate surface in a dendritic pattern, or even detach from the substrate surface and precipitate at the bottom of the solution, resulting in a lower than expected deposition amount on the substrate. This affects the electrode's response to the ion to be tested, leading to insufficient speed and a less obvious response potential. Similarly, excessive concentration or current density can also cause the deposit to detach. Controlling the surface spatial structure and actual surface area further controls the performance of this anion-selective electrode; and by controlling the concentration ratio, electrodeposition time, and current density, the amount of target products generated on the two electrodes is controlled to create a potential difference between the two electrodes in the solution to be tested, thereby altering the ion activity of the electrodes. This invention uses non-precious metal salts and conductive substrate materials as the main raw materials, which are abundant in nature and inexpensive, thus facilitating industrial production. The preparation method involved in this invention is simple and reliable, with uniform electrode size, large specific surface area, high electrochemical activity, high sensitivity and wide detection limit, high selectivity, and superior performance, providing a new approach for the industrialization of anion-selective electrodes.

[0180] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing an anion-selective electrode, characterized in that: Includes the following steps: (I) Preparation of a conductive substrate loaded with a large amount of the target metal element: The conductive substrate was placed in a solution containing the target metal ions for long-term deposition. After deposition, the conductive substrate was removed, cleaned, and dried to obtain a conductive substrate loaded with a large amount of the target metal element. (II) Preparation of high-loading electrodes: The conductive substrate loaded with a large amount of target metal element obtained in step (I) is used as the anode. Electrolysis is carried out in an anionic solution containing anion that can form a sparingly soluble salt with the target metal ions. After electrolysis, the substrate is taken out, cleaned, and dried to obtain an electrode composed of the target metal and its sparingly soluble salt, which is used as a high loading electrode. (III) Preparation of a conductive substrate loaded with a small amount of the target metal element: The conductive substrate was placed in the same solution containing the target metal ions as in step (I) for short-term deposition. After deposition, the conductive substrate was removed, cleaned, and dried to obtain a conductive substrate loaded with a small amount of the target metal element. (IV) Fabrication of low-load electrodes: The conductive substrate loaded with a small amount of the target metal element obtained in step (III) is used as the anode. Electrolysis is performed in an anionic solution containing anion that can form a sparingly soluble salt with the target metal ions. After electrolysis, the substrate is taken out, cleaned, and dried to obtain an electrode composed of the target metal and its sparingly soluble salt, which is used as a low-load electrode. The electrode composed of the target metal and its sparingly soluble salt is an Ag / AgCl electrode, an Ag / AgBr electrode, an Ag / Ag2S electrode, an Ag / AgI electrode, or an Ag / Ag2SO4 electrode.

2. The method for preparing anion-selective electrode according to claim 1, characterized in that: The duration of long-term deposition in step (I) is longer than the duration of short-term deposition in step (III); the duration of long-term deposition in step (I) is 2000s to 6000s; the duration of short-term deposition in step (III) is 25s to 1600s.

3. The method for preparing anion-selective electrode according to claim 1, characterized in that: The deposition method is electrochemical deposition, magnetron sputtering, or vapor deposition.

4. The method for preparing anion-selective electrode according to claim 1, characterized in that: The electrolysis method is electrochemical deposition, which is constant current electrodeposition, and the current density of the constant current electrodeposition is 1 mA·cm². -2 ~15mA·cm -2 .

5. The method for preparing anion-selective electrode according to claim 1, characterized in that: The concentration of the target metal ion in the solution is 0.02–0.1 M; the solution containing the target metal ion is a silver nitrate solution or a lead nitrate solution.

6. The method for preparing anion-selective electrode according to claim 1, characterized in that: The anionic solution that can form a sparingly soluble salt with the target metal ion is a solution containing any one or more of chloride ions, bromide ions, iodide ions, sulfide ions, or sulfate ions, and the concentration of the anion in the anionic solution ranges from 0.1 to 2.5 M.

7. An anion-selective electrode prepared by the method according to any one of claims 1 to 6, characterized in that: It includes a high-load electrode and a low-load electrode. Both the high-load electrode and the low-load electrode are electrodes composed of a conductive substrate loaded with a metal / metal sparingly soluble salt. The loading amount of the metal / metal sparingly soluble salt on the high-load electrode is greater than that on the low-load electrode. The metal / metal sparingly soluble salt has a structure in which metal particles are coated with metal particles.

8. The anion-selective electrode according to claim 7, characterized in that: The conductive substrate material is any one or more of the following: laser-etched PI film, graphite, graphene, glassy carbon, inert metal, or semiconductor material; the inert metal is platinum, gold, or titanium; and the semiconductor material is a silicon wafer.

9. An application of an anion-selective electrode prepared by the method according to any one of claims 1 to 6, characterized in that: An electrode pair consisting of a high-load electrode and a low-load electrode is placed in an anionic solution containing anions that can form sparingly soluble salts with the target metal ions. Within a certain concentration range, the open-circuit potential between the two electrodes exhibits a linear relationship with the logarithm of the anion concentration, which is used for the selective determination of anions.

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