阅读说明：本技术 形稳电极的涂层组合物、形稳电极、制备方法及应用 (Coating composition of dimensionally stable electrode, preparation method and application ) 是由 武晓峰 陈运法 于 2019-09-30 设计创作，主要内容包括：一种形稳电极的涂层组合物、形稳电极、制备方法及应用,其中形稳电极的涂层组合物,包括催化活性组分的前驱体溶液,以及添加剂；所述催化活性组分的前驱体溶液为含有Ti、Ru、Ir中的一种或多种元素的溶液,所述添加剂为包括多元羧酸和多元醇的混合溶液；所述添加剂中多元羧酸与多元醇配比按照羧基/羟基摩尔比例为1∶1～3∶1；且所述催化活性组分的前驱体溶液中Ru、Ir、Ti三种金属元素总摩尔与多元羧酸摩尔之比为1∶1～3∶1。采用本发明增加涂料与金属基体的润湿性与结合力,可有效调控电极活性表面积,增加电极催化活性组份的均匀分散、提高电极的运行稳定性。(A coating composition of a dimensionally stable electrode, the dimensionally stable electrode, a preparation method and application thereof, wherein the coating composition of the dimensionally stable electrode comprises a precursor solution of a catalytic active component and an additive; the precursor solution of the catalytic active component is a solution containing one or more elements of Ti, Ru and Ir, and the additive is a mixed solution containing polycarboxylic acid and polyhydric alcohol; in the additive, the ratio of polycarboxylic acid to polyol is 1: 1-3: 1 according to the molar ratio of carboxyl to hydroxyl; and the ratio of the total mole of three metal elements of Ru, Ir and Ti to the mole of the polycarboxylic acid in the precursor solution of the catalytic active component is 1: 1-3: 1. The invention can increase the wettability and binding force of the coating and the metal matrix, effectively regulate and control the active surface area of the electrode, increase the uniform dispersion of the catalytic active components of the electrode and improve the operation stability of the electrode.)

1. A dimensionally stable electrode coating composition comprising a solution of a precursor of a catalytically active component, and an additive; wherein:

the precursor solution of the catalytic active component is a solution containing one or more elements of Ti, Ru and Ir,

the additive is a mixed solution containing polycarboxylic acid and polyalcohol;

wherein the ratio of the polycarboxylic acid to the polyol in the additive is 1: 1-3: 1 according to the molar ratio of carboxyl to hydroxyl; and the ratio of the total mole of three metal elements of Ru, Ir and Ti to the mole of the polycarboxylic acid in the precursor solution of the catalytic active component is 1: 1-3: 1.

2. A dimensionally stable electrode coating composition according to claim 1, wherein the molar ratio of the three metal elements in the precursor solution of the catalytically active component is Ir/Ru/Ti ═ x/(3-x)/7, wherein x is in the range of 0 to 1.8;

preferably, the total molar concentration (Ru + Ir + Ti) of the three metal elements in the precursor solution of the catalytic active component is 0.3-0.5 mol/L.

3. A dimensionally stable electrode coating composition according to claim 2, characterized in that the precursor solution of the catalytically active component is TiO-containing₂Sol, RuCl₃、H₂IrCl₆A mixed aqueous solution of hydrochloric acid solution.

4. A dimensionally stable electrode coating composition according to claim 3, characterized in that said TiO₂The sol is Ti (O-t-C)₃H₇)₄Or Ti (O-n-C)₄H₉)₄Is obtained by catalytic hydrolysis of an acid catalyst;

preferably, the acid catalyst is one or more of hydrochloric acid, acetic acid and nitric acid.

5. A dimensionally stable electrode coating composition according to claim 1, characterized in that the polycarboxylic acid is a water-soluble polybasic organic carboxylic acid;

preferably, the polycarboxylic acid comprises one or more of oxalic acid, malonic acid, succinic acid, citric acid and malic acid;

preferably, the concentration of the polycarboxylic acid in the additive is 0.05-0.2 mol/L.

6. A dimensionally stable electrode coating composition according to claim 1, wherein the polyol comprises one or more of ethylene glycol, propylene glycol, trimethylene glycol and 1, 3-butanediol.

7. A method of making a dimensionally stable electrode comprising the steps of:

uniformly mixing the coating composition of the dimensionally stable electrode according to any one of claims 1 to 6, and carrying out a gelling reaction to obtain a mixed sol;

dipping a metal matrix in the mixed sol, and sintering the metal matrix dipped with the mixed gel to obtain the metal matrix containing the catalyst coating;

and repeating the dipping and sintering processes on the metal substrate containing the catalyst coating to obtain the dimensionally stable electrode.

8. The method for producing a dimensionally stable electrode according to claim 7, wherein the conditions of the gelation reaction include: stirring at a speed of 150-400 rpm at 90-120 ℃ for 1-3 hours;

preferably, the dipping and sintering process is repeated for 10-15 times;

preferably, the dipping time of the dipping is 10-20 minutes; then drying in an oven at 80-120 ℃;

preferably, the specific operating conditions of the sintering include: sintering at 350-550 ℃ for 10-20 minutes, and quickly cooling to room temperature after sintering;

preferably, the last sintering temperature is 350-550 ℃, and the sintering time is 1-2 hours.

9. A dimensionally stable electrode, characterized by being produced by the production method according to any one of claims 7 to 8.

10. Use of a dimensionally stable electrode according to claim 9 in the field of the electrolysis of sodium chloride solutions for the preparation of sterile water.

Technical Field

The invention relates to the field of electrochemical catalysis application, in particular to a coating composition of a dimensionally stable electrode, the dimensionally stable electrode, a preparation method and application.

Background

Hypochlorous acid or hypochlorite disinfectants are the most commonly used and most effective disinfectants in sewage treatment, food industry and environmental protection. Compared with solid chlorine-containing disinfectants (such as bleaching powder, trichloroisocyanuric acid and the like), chlorine dioxide disinfectant powder, potassium monopersulfate disinfectant powder, liquid chlorine, chlorine dioxide and other chlorine disinfection methods, hypochlorous acidThe acid or sodium hypochlorite disinfection technology is more broad-spectrum, safe and efficient; and the raw material salt (NaCl) is easy to obtain and convenient to purchase, transport and store. The process of preparing alkali by electrolysis with ion exchange membrane method is widely applied in chlor-alkali industry. Inserting a layer of ion selective permeation membrane between the cathode and the anode of the electrolytic cell to divide the electrolytic cell into an anode chamber and a cathode chamber; saturated saline solution is injected into the anode chamber, and NaOH solution is injected into the cathode chamber; after electrification, electrolysis of water at the cathode generates H₂And release OH^-And Na electromigration from the anode⁺Combining to form a high-concentration NaOH solution; anodic generation of Cl^-Electrocatalytic oxidation reaction to produce Cl₂(ii) a Because the ionic membrane is a cation selective permeable membrane; the anode chamber has the principle that no OH-is transferred into the anode chamber and only Cl is present^-(ii) a After gas-liquid separation, Cl is separated₂Introducing into alkaline solution generated at the cathode (mostly generated at the cathode) to absorb to form sodium hypochlorite solution with higher concentration (about 10%); however, the method usually causes larger internal resistance due to the ionic membrane and has higher energy consumption; in addition, the membrane is easy to pollute and the replacement cost is high; in addition, a large amount of corrosive Cl is generated near the electrode₂The operation cost and the environmental load of equipment are greatly increased by the high-concentration alkali liquor; for some special applications, such as: the safety and the economical efficiency are not good in the occasions of on-site disaster relief and disinfection and household sanitation and disinfection. In contrast, the method for preparing hypochlorous acid or hypochlorite by electrolyzing saline solution without diaphragm electrolyzer can utilize the generated OH-at the cathode to migrate to the vicinity of the anode under the action of electric field and generate Cl₂Reacting to produce HCl and HClO or NaClO, reducing Cl₂(iii) release overflow; the method for utilizing the diaphragm-free electrolysis has the advantages of simple equipment, low operation cost and the like; however, the method of producing hypochlorous acid or hypochlorite by non-diaphragm electrolysis of a saline solution has disadvantages such as low concentration of the disinfectant and low current efficiency. Therefore, the disinfectant prepared by electrolyzing the salt solution by the diaphragm-free method has the advantages and disadvantages for the technical requirements of specific occasions (such as household economy and convenience of disaster relief sites); combining the two electrolysis methods, the advantages and disadvantages of the two technologies are complemented to a certain extent, and specifically, a mixed solution of NaClO and NaCl can be obtained by electrolyzing saline solution without a diaphragm; electrolyzing the mixed solution of NaClO and NaCl by using an ion diaphragm methodHigh-concentration HClO disinfectant is obtained in the polar room.

The anode is a generating source of electrochemical catalytic oxidation reaction, and is directly oxidized or indirectly oxidized; the choice of anode material has a crucial influence on the effectiveness of electrochemical water treatment. The influence factors of hypochlorous acid or hypochlorite concentration are related to the electrode spacing, the applied voltage, NaCl concentration, pH value and other factors, and the key is the electrochemical activity of the catalytic coating of the anode^-The key factors of the electrocatalysis catalyst such as composition, structure, texture and the like. Beer invented a dimensionally stable anode (DSC) catalyst (such as: RuO) since 1968₂/TiO₂/Timesh), the DSC electrocatalyst greatly promotes the development of the chlor-alkali chemical industry due to the excellent characteristics of strong coating adhesion, good mechanical stability, high catalytic activity and the like, and is also an important electrocatalysis electrode system in the fields of seawater desalination, environmental purification and the like. Wherein Ti/IrO₂、Ti/RuO₂And Ti/IrO-RuO₂The electrode has a lower chlorine evolution potential and is more suitable to be used as an anode material for electrochemical water treatment. The DSC anode manufacturing process is to attach the metal with strong catalytic activity or the oxide coating thereof on the surface of a substrate by using methods such as brushing sintering or chemical deposition and the like, and then to obtain the catalyst after calcination. The wetting condition of the coating composition and system and the metal matrix and the control of the sintering process have important influence on the distribution of active components on the surface of the electrode, pores and adhesion; in the traditional process, an alcohol solution of metal salt is directly coated on a metal titanium sheet, and the metal titanium sheet is dried and then calcined at high temperature; because the salt precipitation caused by the volatilization of the used alcohol has poor binding force with the metal matrix, the catalyst coating usually falls off; in addition, the poor compatibility and the thermal property mismatch of different metal oxides after sintering cause a large number of cracks, and the stability and the service life of the electrode coating are reduced. Therefore, a chemical modification method is used to improve the compatibility between the sintered metal oxides; common modifiers include metal oxides such as Sn, Mn, Sb, Ir, and the like. Such as: sn element added modified Ti/IrO₂-RuO₂The surface crack distribution of the electrode is changed, and the flatness of the electrode is greatly improved; for weakening clustered grainsSeparate out and improve the para Cl^-Electrocatalytic activity of (a); but still has the problems of noble metal waste, uneven catalyst coating and the like caused by the falling of mixed metal salt due to solvent volatilization in the step of coating the electrocatalyst, and seriously influences the catalytic effect, the current efficiency and the service life of the electrode in the operation process of the electrode.

Disclosure of Invention

In view of the above, the main object of the present invention is to provide a coating composition for dimensionally stable electrodes, a dimensionally stable electrode, a method for preparing the same and applications thereof, which are intended to at least partially solve at least one of the above-mentioned technical problems.

As an aspect of the present invention, there is provided a coating composition for a dimensionally stable electrode, including a precursor solution of a catalytically active component, and an additive; wherein:

the precursor solution of the catalytic active component is a solution containing one or more elements of Ti, Ru and Ir,

the additive is a mixed solution containing polycarboxylic acid and polyalcohol;

wherein the ratio of the polycarboxylic acid to the polyol in the additive is 1: 1-3: 1 according to the molar ratio of carboxyl to hydroxyl; and the ratio of the total mole of three metal elements of Ru, Ir and Ti to the mole of the polycarboxylic acid in the precursor solution of the catalytic active component is 1: 1-3: 1.

As another aspect of the present invention, there is provided a method of preparing a dimensionally stable electrode, comprising the steps of:

uniformly mixing the coating composition of the dimensionally stable electrode, and carrying out a gelling reaction to obtain mixed sol;

dipping a metal matrix in the mixed sol, and sintering the metal matrix dipped with the mixed gel to obtain the metal matrix containing the catalyst coating;

and repeating the dipping and sintering processes on the metal substrate containing the catalyst coating to obtain the dimensionally stable electrode.

As a further aspect of the present invention, there is provided a dimensionally stable electrode prepared by the above-described preparation method.

As a further aspect of the invention, there is provided the use of a dimensionally stable electrode as described above in the field of the electrolysis of sodium chloride solutions for the preparation of sterile water.

Based on the technical scheme, the invention at least has one or part of the following beneficial effects:

(1) according to the invention, a hydrophilic viscous mixed sol is formed by utilizing the sol-gel reaction of organic polycarboxylic acid and polyhydric alcohol, so that the adhesive property of a catalytic active component on a metal titanium substrate is improved, and the high-temperature sintering property of an electrode catalyst coating is improved; the carbide degraded by the organic polymer at high temperature is used for inhibiting the excessive growth of electrode mixed oxide particles, preventing the shrinkage caused by thermal stress and inhibiting the growth of cracks; and the surface flatness of the electrode is improved.

(2) The preparation method of the invention takes water as the main solvent, greatly reduces the use of volatile organic solvent, does not need special reaction equipment, has simple operation process and is easy to amplify the preparation.

Drawings

FIG. 1 is a scanning electron microscope image of the surface of a dimensionally stable electrode DSC-1 catalyst coating prepared in example 1 of the present invention;

FIG. 2 is a scanning electron microscope image of the surface of a dimensionally stable electrode DSC-2 catalyst coating prepared in example 2 of the present invention;

FIG. 3 is a scanning electron microscope image of the surface of a dimensionally stable electrode DSC-3 catalyst coating prepared in example 3 of the present invention;

FIG. 4 is a scanning electron microscope image of the surface of a dimensionally stable electrode DSC-4 catalyst coating prepared in example 4 of the present invention;

FIG. 5 is a scanning electron microscope image of the surface of a dimensionally stable electrode DSC-5 catalyst coating prepared in example 5 of the present invention;

FIG. 6 is a scanning electron microscope image of the surface of a dimensionally stable electrode DSC-6 catalyst coating prepared in example 6 of the present invention;

FIG. 7 is a scanning electron microscope image of the surface of a dimensionally stable electrode DSC-R catalyst coating prepared in comparative example 1 of the present invention.

Detailed Description

In order that the objects, technical solutions and advantages of the present invention will become more apparent, the present invention will be further described in detail with reference to the accompanying drawings in conjunction with the following specific embodiments.

The patent provides a preparation method of a dimensionally stable electrode (DSC), which utilizes the reaction of organic polybasic acid and polyalcohol to form polymer sticky sol fixed catalytic active metal mixed salt and increase the adhesion of electrocatalyst precursor mixed salt on metal titanium; can effectively prevent falling off; in the sintering process, the mixed metal oxide can be fixed by partial pyrolysis of the polymer sol, so that the sintering performance is improved; the flatness and the electrocatalysis performance of the catalyst coating are improved; the method effectively overcomes the disadvantages of cracking, easy falling and the like of the catalyst coating of the electrolytic salt solution electrode prepared by the traditional method, which reduce the stability and the service life of the electrode.

In an embodiment of the present invention, there is provided a coating composition for a dimensionally stable electrode, including a precursor solution of a catalytically active component, and an additive; wherein:

the precursor solution of the catalytic active component is a solution containing one or more elements of Ti, Ru and Ir,

the additive is a mixed solution containing polycarboxylic acid and polyalcohol;

wherein, the ratio of the polybasic carboxylic acid to the polyhydric alcohol in the additive is 1: 1-3: 1 according to the molar ratio of carboxyl to hydroxyl; and the ratio of the total mole of three metal elements of Ru, Ir and Ti in the precursor solution of the catalytic active component to the mole of the polycarboxylic acid is 1: 1-3: 1.

Further, the molar ratio of three metal elements in the precursor solution of the catalytic active component is Ir/Ru/Ti ═ x/(3-x)/7, wherein the value range of x is 0-1.8;

preferably, the total molar concentration (Ru + Ir + Ti) of the three metal elements in the precursor solution of the catalytic active component is 0.3-0.5 mol/L.

Further, the precursor solution of the catalytic active component contains TiO₂Sol, RuCl₃、H₂IrCl₆A mixed aqueous solution of hydrochloric acid solution.

Further, TiO₂The sol is Ti (O-t-C)₃H₇)₄Or Ti (O-n-C)₄H₉)₄Catalyzed by acid catalystsChemical hydrolysis is carried out to obtain;

preferably, the acid catalyst is one or more of hydrochloric acid, acetic acid, and nitric acid.

Further, the polycarboxylic acid is a water-soluble polybasic organic carboxylic acid;

preferably, the polycarboxylic acid comprises one or more of water-soluble polybasic organic carboxylic acids such as oxalic acid, malonic acid, succinic acid, citric acid, malic acid and the like;

preferably, the concentration of the polycarboxylic acid in the additive is 0.05-0.2 mol/L.

Further, the polyhydric alcohol comprises one or more of ethylene glycol, propylene glycol, glycerol and 1, 3-butanediol.

In an embodiment of the present invention, there is also provided a method of preparing a dimensionally stable electrode, including the steps of:

uniformly mixing the coating composition of the dimensionally stable electrode, and carrying out a gelling reaction to obtain mixed sol;

dipping a metal matrix in the mixed sol, and sintering the metal matrix dipped with the mixed gel to obtain the metal matrix containing the catalyst coating;

and repeating the dipping and sintering processes on the metal matrix containing the catalyst coating to obtain the dimensionally stable electrode.

Further, the conditions of the gelling reaction include: stirring at a speed of 150-400 rpm at 90-120 ℃ for 1-3 hours;

preferably, the dipping and sintering process is repeated for 10-15 times;

preferably, the dipping time of the dipping is 10 to 20 minutes; then drying in an oven at 80-120 ℃;

preferably, the specific operating conditions of sintering include: sintering at 350-550 ℃ for 10-20 minutes, and quickly cooling to room temperature after sintering;

preferably, the last sintering temperature is 350-550 ℃, and the sintering time is 1-2 hours.

In the embodiment of the invention, the dimensionally stable electrode is also provided and is prepared by the preparation method.

In the embodiment of the invention, the application of the dimensionally stable electrode in the field of preparing sterilized water by electrolyzing sodium chloride solution is also provided.

The following examples further illustrate the preparation of dimensionally stable anodes for the preparation of sodium hypochlorite by electrocatalysis of NaCl, but are not limited to the following examples, and any equivalent changes made according to the technical solution of the present invention are within the scope of the present invention.