CN113430561B - Oxygen evolution electrocatalytic material based on transition metal salt, preparation method and application thereof - Google Patents

Abstract

The invention discloses an oxygen evolution electrocatalytic material based on transition metal salt, a preparation method and application thereof. The oxygen evolution electrocatalytic material can be prepared by adopting cobalt ions as central ions, doping a certain amount of nickel ions, taking potassium ions or sodium ions as charge balance ions, taking fluorine ions as ligands and carrying out coordination reaction of the cobalt ions and the ligands in a solvent. And the oxygen evolution electro-catalytic material has oxygen evolution overpotential obviously lower than that of an iridium electrode when being applied to water electrolysis hydrogen production, shows excellent oxygen evolution electro-catalytic performance and electro-catalytic stability, and is expected to be widely applied to the field of new energy.

Description

Oxygen evolution electrocatalytic material based on transition metal salt, preparation method and application thereof

Technical Field

The invention relates to an electrocatalytic oxygen evolution material, in particular to a preparation method of an electrocatalytic oxygen evolution material based on transition metal salt with cobalt ions as coordination center ions and fluorine ions as ligands, and application of the electrocatalytic oxygen evolution material in the aspect of electrocatalytic oxygen evolution in water electrolysis hydrogen production, and belongs to the technical field of renewable energy materials.

Background

At present, photovoltaic power generation, wind power generation and hydroelectric power generation are utilized, and then electrolysis water hydrogen evolution is an effective way for realizing carbon-to-peak carbon neutralization. In the existing electrolytic water hydrogen separation method, noble metals ruthenium, iridium and oxides thereof are mostly needed to be used as oxygen separation electrocatalysts, and the noble metals have high price and limited reserves, so that the noble metals are difficult to apply on a large scale. For a long time, the industry has long sought to develop inexpensive and efficient non-noble metal electrocatalysts to achieve low cost hydrogen production by electrolysis of water.

Although some transition metal oxides or hydroxides are suggested by researchers to be promising as oxygen evolution electrocatalytic materials, the oxygen evolution overpotential of the transition metal oxides or hydroxides is too large, and excessive hydrogen ions generated by oxygen evolution can locally dissolve the transition metal oxide or hydroxide electrodes, so that the electrolysis efficiency and the service life of the transition metal oxide or hydroxide electrodes are affected, and therefore, the requirements of practical application cannot be met.

Disclosure of Invention

In order to overcome the defects of the existing electrolytic water oxygen evolution electrocatalyst, reduce energy consumption and improve current efficiency, the invention aims to design a novel transition metal salt-based oxygen evolution electrocatalyst material, a preparation method thereof and application of the electrolytic water oxygen evolution electrocatalyst in hydrogen production.

In order to achieve the purpose of the invention, the technical scheme adopted by the invention comprises the following steps:

the embodiment of the invention provides a preparation method of an oxygen evolution electrocatalytic material based on transition metal salt, which comprises the following steps: the uniform liquid phase mixed reaction system containing hydrogen fluoride, hydroxide, cobalt salt and nickel salt is reacted for 0.5 to 2 hours under the protection of nitrogen at the temperature of-2 to 99 ℃ to obtain the oxygen evolution electrocatalytic material based on the transition metal salt, and the chemical formula of the oxygen evolution electrocatalytic material is MCo _(1-x) Ni _x F ₃ M represents a charge balance ion, and 0 < x < 1.

In some embodiments, the preparation method specifically includes:

electrolyte is added into the mixed solution of hydrogen fluoride and hydroxide, and the temperature of the mixed solution is controlled below minus 2 ℃;

and (3) mixing and grinding cobalt salt and nickel salt, directly adding the mixture into the mixed solution, carrying out ultrasonic oscillation, and then heating to 85-99 ℃ to continue to react for 0.5-2h to obtain the oxygen evolution electrocatalytic material based on the transition metal salt.

In some embodiments, the molar ratio of nickel salt to cobalt salt is y:1, wherein y > 0, preferably 0 < y < 1.

The embodiment of the invention also provides the oxygen evolution electrocatalytic material based on the transition metal salt, which is prepared by the method, and has a crystal structure of perovskite type cubic crystal system and a space group of P _m 3 _m A space group represented by the chemical formula MCo _(1-x) Ni _x F ₃ M represents a charge balance ion, and 0 < x < 1.

The embodiment of the invention also provides application of the oxygen evolution electrocatalytic material based on the transition metal salt as an oxygen evolution electrocatalytic agent in hydrogen production by water electrolysis.

Correspondingly, the embodiment of the invention also provides a method for producing hydrogen by water electrolysis, which comprises the following steps:

preparing the oxygen evolution electrocatalytic material based on the transition metal salt into a carbon paste electrode or a metal-based electrode;

and the carbon paste electrode or the metal-based electrode is used as an oxygen evolution electrode, nickel is used as a hydrogen evolution electrode, and the nickel is matched with an alkaline aqueous solution to form an electrolytic water hydrogen production system, and the electrolytic water hydrogen production is realized by electrifying between the oxygen evolution electrode and the hydrogen evolution electrode.

Compared with the prior art, the novel oxygen evolution electro-catalytic material based on the transition metal salt is generated by adopting cobalt ions as central ions, doping a certain amount of nickel ions, taking potassium ions or sodium ions as charge balance ions and taking fluorine ions as ligands through the coordination reaction of the cobalt ions and the ligands in the solvent, and the oxygen evolution electro-catalytic material has the oxygen evolution overpotential obviously lower than that of an iridium electrode when being applied to hydrogen production by water electrolysis, shows excellent oxygen evolution electro-catalytic performance and electro-catalytic stability, and is expected to be widely applied to the field of new energy.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments described in the present invention, and other drawings may be obtained according to the drawings without inventive effort to those skilled in the art.

FIG. 1 is a schematic illustration of KNIF in an exemplary embodiment of the invention ₃ 、KCoF ₃ 、KCo _0.75 Ni _0.25 F ₃ X-ray powder diffraction pattern of (2);

FIG. 2A is a KCo in an exemplary embodiment of the present invention _0.75 Ni _0.25 F ₃ Is a transmission electron microscope image;

FIG. 2B is a KCo in an exemplary embodiment of the present invention _0.75 Ni _0.25 F ₃ Is a pattern of electron diffraction patterns;

FIG. 2C is a KCo in an exemplary embodiment of the present invention _0.75 Ni _0.25 F ₃ Is a high power transmission electron microscope image;

FIG. 2D is a schematic illustration of KNIF in an exemplary embodiment of the invention ₃ Is a transmission electron microscope image;

FIG. 2E is a KNIF in an exemplary embodiment of the invention ₃ Is a pattern of electron diffraction patterns;

FIG. 2F is a KNIF in an exemplary embodiment of the invention ₃ Is high power transmissionA mirror image;

FIG. 2G is a KCoF in an exemplary embodiment of the invention ₃ Is a transmission electron microscope image;

FIG. 2H is a KCoF in an exemplary embodiment of the invention ₃ Is a pattern of electron diffraction patterns;

FIG. 2I is a KCoF in an exemplary embodiment of the invention ₃ Is a high power transmission electron microscope image;

FIG. 3 is a KCo in an exemplary embodiment of the present invention _0.7s Ni _0.25 F ₃ EDX profile of (c);

FIG. 4 is a diagram of graphite, KNIF in an exemplary embodiment of the invention ₃ 、KCo _0.5 Ni _0.5 F ₃ 、IrO ₂ 、KCoF ₃ 、KCo _0.2s Ni _0.75 F ₃ 、KCo _0.75 Ni _0.25 F ₃ Wherein curve a represents graphite and curve b represents KNIF ₃ Curve c represents KCo _0.5 Ni _0.5 F ₃ Curve d represents IrO ₂ Curve e represents kcofs ₃ Curve f represents KCo _0.25 Ni _0.75 F ₃ Curve g represents KCo _0.75 Ni _0.25 F ₃ ；

FIG. 5 is a KCo in an exemplary embodiment of the present invention _0.75 Ni _0.25 F ₃ Oxygen evolution i-t graph of (c).

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the following detailed description of the embodiments of the present invention will be given with reference to the accompanying drawings. Examples of these preferred embodiments are illustrated in the accompanying drawings. The embodiments of the invention shown in the drawings and described in accordance with the drawings are merely exemplary and the invention is not limited to these embodiments.

It should be noted here that, in order to avoid obscuring the present invention due to unnecessary details, only structures and/or processing steps closely related to the solution according to the present invention are shown in the drawings, while other details not greatly related to the present invention are omitted.

One aspect of the embodiment of the invention provides a preparation method of a novel oxygen evolution electrocatalytic material based on transition metal salt and application of the material in water electrolysis and hydrogen production. The preparation method adopts cobalt ions as central ions, is doped with a certain amount of nickel ions, adopts potassium ions or sodium ions as charge balance ions, adopts fluorine ions as ligands, and generates the novel oxygen evolution electrocatalytic material based on transition metal salt through the coordination reaction of the cobalt ions and the ligands in a solvent.

In some exemplary embodiments, the method of preparing includes: the uniform liquid phase mixed reaction system containing hydrogen fluoride, hydroxide, cobalt salt and nickel salt is reacted for 0.5 to 2 hours under the protection of nitrogen at the temperature of-2 to 99 ℃ to obtain the oxygen evolution electrocatalytic material based on the transition metal salt, and the chemical formula of the oxygen evolution electrocatalytic material is MCo _(1-x) Fe _x F ₃ M represents a charge balance ion, and 0 < x < 1.

Further, M includes potassium ions, sodium ions, etc., but is not limited thereto.

In some exemplary embodiments, the method of preparing further comprises: introducing nitrogen into the uniform liquid phase mixed reaction system to deoxidize for more than 20 minutes.

In some exemplary embodiments, the preparation method specifically includes:

adding electrolyte into the mixed solution of hydrogen fluoride and hydroxide, introducing nitrogen to remove oxygen for more than 20 minutes, and controlling the temperature of the mixed solution below-2 ℃;

grinding cobalt salt and nickel salt, directly adding the ground cobalt salt and nickel salt into the mixed solution for introducing nitrogen and deoxidizing, carrying out ultrasonic oscillation, and then heating to 85-99 ℃ for continuous reaction for 0.5-2h to obtain the oxygen evolution electrocatalytic material based on transition metal salt.

In other exemplary embodiments, the preparation method may further include: directly taking fluoride solution, introducing nitrogen to remove oxygen for more than 20 minutes, and controlling the temperature of the solution to be-2 ℃ in order to prevent metal ions from hydrolyzing. To reach-2 ℃, electrolyte is added according to a numerical principle.

Further, the fluoride used in the present invention includes potassium fluoride, sodium fluoride, etc., but is not limited thereto.

Further, the electrolyte includes any one or a combination of two or more of calcium chloride, potassium sulfate, sodium sulfate, potassium nitrate, sodium nitrate, potassium chloride, sodium chloride, glucose, and the like, but is not limited thereto.

Further, the ultrasonic oscillation time is less than 10 hours.

In some exemplary embodiments, the preparation method specifically includes: mixing hydrofluoric acid and hydroxide solution to obtain the fluoride solution, wherein the hydroxide solution comprises potassium hydroxide and/or sodium hydroxide solution and the like.

In some exemplary embodiments, the molar ratio of nickel salt to cobalt salt is y:1, where y > 0, preferably 0 < y < 1.

In some exemplary embodiments, the cobalt salt includes, but is not limited to, cobalt sulfate (CoSO) ₄ ) Cobalt chloride (CoCl) ₂ ) Cobalt nitrate Co (NO) ₃ ) ₂ And the like, or a combination of any one or two or more thereof.

In some exemplary embodiments, the nickel salt includes, but is not limited to, nickel sulfate (NiSO ₄ ) Nickel chloride (NiCl) ₂ ) Nickel nitrate (Ni (NO) ₃ ) 2), or the like.

In some exemplary embodiments, the method of preparing further comprises: after the reaction is completed, standing and layering are carried out, solids are separated out, washing and drying are carried out, and the oxygen evolution electrocatalytic material based on the transition metal salt is obtained.

In some more specific exemplary embodiments, the preparation method of the oxygen evolution electrocatalytic material based on the transition metal salt specifically comprises the following steps:

(1) Taking 50mL of 3mol/L KF, and controlling the temperature of the solution to be minus 2 ℃ to prevent metal ions from hydrolyzing;

(2) In order to reach-2 ℃, a certain amount of electrolyte is added according to a principle of digitality, so that the temperature of the solution can be reduced to-2 ℃; and then taking 0.05mol of cobalt salt, adding a certain amount of Ni (II) salt into the cobalt salt, wherein the molar ratio of Ni (II) to Co can be (0-1) to 1, and even the molar amount of Ni (II) can be larger than that of Co. The XRD diffraction peak of the alloy shifts according to the different content of Ni (II);

(3) Electrolytes added according to the principle of colligation include, but are not limited to, calcium chloride, potassium sulfate, sodium sulfate, potassium nitrate, sodium nitrate, potassium chloride, sodium chloride, and even substances with colligation such as glucose that can reduce temperature;

(4) Grinding cobalt salt and Ni (II) salt, directly adding into the KF solution, and stirring for 0.0-10.0h by ultrasonic; then the temperature is increased to 85-99 ℃, and the product is obtained after continuous reaction. Standing for layering, separating out solid, washing and drying to obtain the nickel doped trifluoro cobaltate oxygen evolution electrocatalyst.

In another aspect, the invention provides an oxygen evolution electrocatalytic material based on a transition metal salt prepared by the method, which has a perovskite type cubic crystal system and a space group of P _m 3 _m A space group represented by the chemical formula MCo _(1-x) Ni _x F ₃ M represents a charge balance ion, and 0 < x < 1.

Further, M includes potassium ions, sodium ions, etc., but is not limited thereto.

Another aspect of the embodiment of the invention provides the application of the oxygen evolution electrocatalytic material based on transition metal salt as an oxygen evolution electrocatalyst in the hydrogen production by water electrolysis.

Accordingly, another aspect of an embodiment of the present invention also provides a method for producing hydrogen by electrolysis of water, including:

preparing the oxygen evolution electrocatalytic material based on the transition metal salt into a carbon paste electrode or a metal-based electrode;

with the transition metal salt based oxygen evolution electrocatalytic material (MCo _(1-x) Ni _x F ₃ ) The prepared carbon paste electrode or metal-based electrode is an oxygen evolution electrode, nickel is used as a hydrogen evolution electrode and is matched with an alkaline aqueous solution to form an electrolytic water hydrogen production system, and the electrolytic water hydrogen production is realized by electrifying between the oxygen evolution electrode and the hydrogen evolution electrode.

By means of the technical scheme, cobalt ions are adopted as central ions, a certain amount of nickel ions are doped, potassium ions or sodium ions are adopted as charge balance ions, fluorine ions are adopted as ligands, and novel electrocatalytic oxygen evolution materials are generated through coordination reaction of the cobalt ions and the ligands in a solvent, and oxygen evolution overpotential of the oxygen evolution electrocatalytic materials is obviously lower than that of iridium electrodes when the oxygen evolution electrocatalytic materials are applied to hydrogen production by water electrolysis, so that the oxygen evolution electrocatalytic materials have excellent oxygen evolution electrocatalytic performance and electrocatalytic stability, and are expected to be widely applied to the field of new energy.

The technical solution of the present invention will be described in further detail below with reference to a number of preferred embodiments and accompanying drawings, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments. It should be noted that the examples described below are intended to facilitate the understanding of the present invention and are not intended to limit the present invention in any way. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention. The experimental methods, in which specific conditions are not noted in the following examples, are generally conducted under conventional conditions or under conditions recommended by the manufacturer.

Comparative example 1

Potassium trifluorocobaltate KCoF ₃ Is prepared from the following steps: to prevent metal ions from hydrolyzing, 3mol/LKF mL was taken and the temperature of the solution was controlled to-2 ℃. In order to reach-2 ℃, solid NaCl is added according to the principle of digitality to saturate the mixture; taking 0.05mol of cobalt salt, grinding, directly adding into the KF solution, and carrying out ultrasonic oscillation for 0.0-10.0h; then keeping the temperature rising rate of 1 ℃/min to 85 ℃, and continuing the reaction for 0.5-2h to obtain the product. Standing for layering, separating out solid, washing and drying to obtain oxygen evolution electrocatalyst KCoF ₃ The X-ray powder diffraction pattern is shown as curve a in FIG. 1, and corresponds to the diffraction pattern corresponding to the standard card number JCPDS 18-1006.

Comparative example 2

Similarly, potassium trifluorocobaltate KNIF ₃ As comparative example 2, the resulting diffraction pattern is shown as curve b in FIG. 1.

Comparative example 3

Taking 0.15mmol KF or NH ₄ F, taking 0.0375mol of cobalt chloride, taking 0.0125mol of nickel chloride, grinding and mixing, placing into a tube furnace, heating to 350 ℃ under the protection of nitrogen flow, keeping the temperature for 2-5 hours, collecting the obtained product, measuring XRD diffraction data of the obtained product, and measuring the diffraction pattern and the diffraction pattern of the obtained productCurve a in fig. 1 is similar.

Example 1

KCo _0.75 Ni _0.25 F ₃ Is prepared from the following steps: taking 50mL of hydrofluoric acid with the concentration of 3mol/L, adding 55mL of KOH with the concentration of 3mol/L, introducing nitrogen, and deoxidizing for 20 minutes; mixing and grinding 0.0375mol of cobalt sulfate and 0.0125mol of nickel sulfate, directly adding the mixture into the solution, maintaining the temperature at 95 ℃ under the condition of ultrasonic oscillation, and reacting for 1h to obtain the product. Standing for layering, separating out solid, washing and drying to obtain oxygen evolution electrocatalyst KCo _0.75 Fe _0.25 F ₃ The XRD diffraction pattern is shown in curve c of FIG. 1.

Example 2

KCo _0.5 Ni _0.5 F ₃ Is prepared from the following steps: taking 50mL of 3mol/L KF, introducing nitrogen, and deoxidizing for 25 minutes; to prevent the metal ions from hydrolyzing, the solution temperature was controlled to-2 ℃. In order to reach-2 ℃, solid NaCl is added according to the principle of digitality to saturate the mixture; grinding 0.025mol of cobalt chloride and 0.025mol of nickel sulfate, directly adding the ground cobalt chloride and the nickel sulfate into the solution, and carrying out ultrasonic oscillation for 0.0-10.0h; then the temperature is increased to 99 ℃ and the reaction is continued for 0.5h to obtain the product. Standing for layering, separating out solid, washing and drying to obtain oxygen evolution electrocatalyst KCo _0.5 Ni _0.5 F ₃ The XRD diffractogram is similar to curve c in figure 1.

Example 3

KCo _0.6 Ni ₀₄ F ₃ Is prepared from the following steps: taking 50mL of 3mol/L KF, introducing nitrogen, and deoxidizing for 30 minutes; to prevent the metal ions from hydrolyzing, the solution temperature was controlled to-2 ℃. In order to reach-2 ℃, solid NaCl is added according to the principle of digitality to saturate the mixture; then 0.03mol of cobalt nitrate and 0.02mol of nickel sulfate are taken, ground and then directly added into the solution, and ultrasonic oscillation is carried out for 0.0-10.0h; then the temperature is increased to 85 ℃, and the reaction is continued for 2 hours to obtain the product. Standing for layering, separating out solid, washing and drying to obtain oxygen evolution electrocatalyst KCo _0.6 Ni _0.4 F ₃ The XRD diffractogram is similar to curve c in figure 1.

The inventors also compared KCoF of comparative example 1 ₃ KFEF of comparative example 2 ₃ And KCo obtained in example 1 _0.75 Fe _0.25 F ₃ Characterization and testing of various properties were performed with the following results:

in the first embodiment 1 of the present invention, a certain amount of Ni (II) salt is added to the cobalt salt, and the molar ratio of Ni (II) to Co may be (0 to 1) to 1, and even the molar amount of Ni (II) may be larger than that of Co. The XRD diffraction peak shifts according to the content of Ni (II) added. Referring to FIG. 1, KCoF ₃ 、KNiF ₃ And KCo _0.75 Ni _0.25 F ₃ XRD pattern of the sample. From the diffraction pattern, KCoF ₃ Diffraction peaks of the electrocatalyst at 2θ= 21.842 °,31.064 °,38.285 ° correspond to kcofs, respectively ₃ (100), (110) and (111) crystal face indices (JCPDS 18-1006), KNIF ₃ Diffraction peaks of the sample at 2θ= 22.143 °,31.484 °,38.806 ° correspond to KNiF, respectively ₃ The (100), (110) and (111) crystal face index (JCPDS 72-0112). Nickel doped fluoride KCo _0.75 Ni _0.25 F ₃ Both the diffraction angle and interplanar spacing at 2θ= 21.982 °,31.264 °,38.506 ° are between those of the single metal fluoride kcofs ₃ With KNIF ₃ In between, it is shown that the bi-metals of Co and Ni change the unit cell size.

Second, the present inventors also compared KCoF of comparative example 1 ₃ KNIF of comparative example 2 ₃ And KCo obtained in example 1 _0.75 Ni _0.25 F ₃ Transmission electron microscopy was performed and the results showed that KCo _0.75 Ni _0.25 F ₃ The morphology, diffraction spots and interplanar spacing of KNIF are shown in FIGS. 2A-2C ₃ The morphology, diffraction spots and interplanar spacing of KCoF are shown in FIGS. 2D-2F ₃ The morphology, diffraction spots and interplanar spacing of (c) are shown in figures 2G-2I. The results of the interplanar spacing are consistent with those of powder diffraction, further showing that the resulting product is perovskite-type fluoride.

Third, the inventor of the present invention refers to KCo _0.75 Ni _0.25 F ₃ EDX spectroscopy was performed as shown in fig. 3A and 3B. Fig. 3A shows that the synthesized sample contains K, co, ni, F elements (Cu from the carrier copper mesh). The element content in the energy spectrum is carried out to obtain FIG. 3B, wherein the atomic percent of Co is 14.43 percent, and the atomic percent of NiThe percentage content is 3.53 percent, and the ratio of Co to Ni is 4.1 to 1, which indicates that Ni replaces part of Co. F was 63.37 atomic percent and K was 18.65 atomic percent, again demonstrating the synthesis of KCo _0.75 Ni _0.25 F ₃ 。

Fourth, the present inventors also compared KCoF of comparative example 1 ₃ KNIF of comparative example 2 ₃ And KCo obtained in example 1 _0.75 Ni _0.25 F ₃ After oxygen evolution performance test, the inventor synthesizes a series of KCo _(1-x) Ni _x F ₃ Electrocatalyst, 0.15g KCo was weighed _(1-x) Ni _x F ₃ The catalyst is made into carbon paste electrode, and the linear scanning curve in 1.0mol/LKOH is shown in figure 4, wherein curve a represents graphite and curve b represents KNIF ₃ Curve c represents KCo _0.5 Ni _0.5 F ₃ Curve d represents IrO ₂ Curve e represents kcofs ₃ Curve f represents KCo _0.25 Ni _0.75 F ₃ Curve g represents KCo _0.75 Ni _0.25 F ₃ 。KCoF ₃ And the oxygen evolution overpotential of the nickel doped potassium trifluorocobaltate is lower than that of the noble metal iridium. The oxygen evolution parameters of each electrode material at a current density of 30 milliamp/cm are shown in table 1. KCo (KCo) _(1-x) Ni _x F ₃ (x < 1.0) the oxygen evolution of the electrocatalyst has an overpotential ratio to the noble metal Ir or IrO ₂ And the oxygen evolution performance is excellent, and the energy consumption of the electrolyzed water can be effectively reduced.

TABLE 1 KCo _(1-x) NI _x F ₃ Electrochemical parameters

*η ₃₀ Is a current density of 30mV/cm ² Over-potential at that time.

Fifth, the inventors also directed to a synthetic KCo _0.75 Ni _0.25 F ₃ Stability of electrocatalyst was tested

To test KCo _0.75 Ni _0.25 F ₃ The i-t curve of the electrode at 0.6V (vs. SCE) is shown in FIG. 5. The current for water electrolysis for 16 hours is 28mA/cm ² The current density of the electrode is essentially unchanged at the end.

Example 4

Taking a series of KCos prepared by the invention _(1-x) Ni _x F ₃ 0.15g of the carbon paste is added into 0.45 g of graphite powder, ground by a mortar, added with a proper amount of silica gel oil and uniformly mixed to obtain the carbon paste. Injecting carbon paste into polytetrafluoroethylene tube with diameter of 3mm, compacting and copper wire to form KCo-containing material _(1-x) Ni _x F ₃ Carbon paste electrodes of oxygen evolution electrocatalysts. The carbon paste electrode is used as an oxygen evolution electrocatalyst, the foam nickel is used as a hydrogen evolution electrode, water is electrolyzed in 1.0mol/LKOH alkaline solution under the pressure of 1.6V tank, oxygen evolution can be observed at the anode, and hydrogen evolution can be observed at the cathode.

In summary, cobalt ions are adopted as central ions, a certain amount of nickel ions are doped, potassium ions or sodium ions are adopted as charge balance ions, fluorine ions are adopted as ligands, and the cobalt ions and the ligands react in a solvent to generate the novel oxygen evolution electro-catalytic material based on transition metal salt, so that the oxygen evolution performance is more excellent after nickel doping, and the electro-catalytic performance is stable.

It should be understood that the above embodiments are merely for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the present invention and implement the same according to the present invention without limiting the scope of the present invention. All equivalent changes or modifications made in accordance with the spirit of the present invention should be construed to be included in the scope of the present invention.

Claims (7)

1. A method for preparing an oxygen evolution electrocatalytic material based on transition metal salts, which is characterized by comprising the following steps: adding electrolyte into the mixed solution of hydrogen fluoride and potassium hydroxide, introducing nitrogen to remove oxygen for more than 20 minutes, and controlling the temperature of the mixed solution below-2 ℃;

mixing and grinding cobalt salt and nickel salt, directly adding the mixture into the mixed solution, carrying out ultrasonic oscillation, and then heating to 85-99 ℃ to continue to react 05-2h to obtain the oxygen evolution electrocatalytic material based on transition metal salt, wherein the chemical formula of the oxygen evolution electrocatalytic material is KCo _0.75 Ni _0.25 F ₃ The crystal structure of the oxygen evolution electrocatalytic material based on the transition metal salt is a perovskite type cubic crystal system, and the space group is P _m 3 _m Space group.

2. The method of manufacturing according to claim 1, characterized in that: the electrolyte is selected from any one or more than two of potassium sulfate, sodium sulfate, potassium nitrate, sodium nitrate, potassium chloride, sodium chloride, calcium chloride and glucose; and/or the ultrasonic oscillation time is less than 10 hours.

3. The method of manufacturing according to claim 1, characterized in that: the cobalt salt is selected from any one or more than two of cobalt sulfate, cobalt chloride and cobalt nitrate; and/or the nickel salt is selected from any one or more than two of nickel sulfate, nickel chloride and nickel nitrate.

4. The method for producing according to claim 1, characterized by further comprising: after the reaction is completed, standing and layering are carried out, solids are separated out, washing and drying are carried out, and the oxygen evolution electrocatalytic material based on the transition metal salt is obtained.

5. An oxygen evolution electrocatalytic material based on a transition metal salt prepared by a process as claimed in any one of claims 1 to 4.

6. The use of the oxygen evolution electrocatalytic material based on transition metal salts as claimed in claim 5 as an oxygen evolution electrocatalyst for the production of hydrogen by electrolysis of water.

7. A method for producing hydrogen by electrolysis of water, comprising:

forming the oxygen evolution electrocatalytic material based on a transition metal salt of claim 5 into a carbon paste electrode or a metal-based electrode;

and the carbon paste electrode or the metal-based electrode is used as an oxygen evolution electrode, nickel is used as a hydrogen evolution electrode, and the nickel is matched with an alkaline aqueous solution to form an electrolytic water hydrogen production system, and the electrolytic water hydrogen production is realized by electrifying between the oxygen evolution electrode and the hydrogen evolution electrode.

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