Preparation method of basic cobalt chloride and ferrocobalt spinel composite electrode and application of seawater electrolysis for hydrogen production

Abstract

The invention relates to the field of electro-catalysis and nano materials, in particular to a preparation method and application of a basic cobalt chloride and ferrocobalt spinel composite electrode material. According to the method, an alkaline low-water high-viscosity alcohol reaction system is adopted, and basic cobalt chloride and a ferrocobalt spinel material are promoted to be deposited on a nickel net at the same time under the high-temperature condition. The prepared basic cobalt chloride and ferrocobalt spinel composite electrode has high catalytic activity and stability, shows good electrochemical performance in a seawater environment, and can be used as a high-activity and high-stability seawater electrolysis hydrogen production electrode.

Description

Technical Field

[0001] This invention relates to the field of electrocatalysis and nanomaterials, specifically to a method for preparing a basic cobalt chloride@cobalt iron spinel composite electrode and its electrochemical application. This material can be widely used in the field of seawater electrolysis for hydrogen production. Background Technology

[0002] Hydrogen energy, as a "carbon-free" energy source, boasts a high calorific value and produces only water as a combustion byproduct, making it a crucial component of the new energy structure. Existing mature hydrogen production methods, such as those from fossil fuel industries, yield hydrogen with low purity and generate carbon emissions during the process. Water electrolysis, particularly seawater electrolysis, produces hydrogen with extremely high purity and zero carbon emissions, making it a vital means of hydrogen energy production. However, seawater electrolysis currently faces two challenges: chlorine evolution and chlorine corrosion. Chlorine evolution is a competing reaction with oxygen evolution at the anode of seawater electrolysis, leading to reduced catalytic activity and electrode corrosion. Chlorine corrosion refers to the formation of soluble coordination ions by chloride ions in seawater that combine with metals on the electrode surface, causing electrode dissolution. This reaction is particularly severe at the anode, resulting in low catalytic activity and stability. Therefore, finding a highly active and stable anode catalyst for seawater electrolysis is crucial to addressing these two issues. Basic cobalt chloride@cobalt-iron spinel composite material, by combining highly active basic cobalt chloride and highly stable cobalt-iron spinel, is expected to become an electrode material with both high catalytic activity and stability, and thus one of the ideal electrode materials for seawater electrolysis. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a method for preparing a basic cobalt chloride@cobalt iron spinel composite electrode and its application in the field of seawater electrolysis for hydrogen production.

[0004] A method for preparing a basic cobalt chloride@cobalt-iron spinel composite electrode includes the following steps: S1. Pre-treat the nickel mesh; S2. A solution A is obtained by mixing a certain amount of deionized water, anhydrous ethanol and glycerol. S3. Weigh out a certain amount of CoCl2·6H2O and FeCl2·4H2O respectively and dissolve them in solution A to obtain solution B; S4. After adding the nickel mesh pretreated in S1 to solution B, add triethylamine and sonicate for a period of time to obtain suspension C. S5. After the suspension C and the nickel mesh are reacted under certain temperature conditions for a period of time, the basic cobalt chloride@cobalt iron spinel composite electrode is obtained.

[0005] Furthermore, in S1, the pretreatment process of the nickel mesh is as follows: after cutting the nickel mesh, it is ultrasonically cleaned with hydrochloric acid, anhydrous ethanol and deionized water for a period of time in sequence to obtain the treated nickel mesh.

[0006] Furthermore, in S1, the concentration of hydrochloric acid is 3 mol / L, and the time condition for ultrasonic cleaning with hydrochloric acid is 10-20 min; The ultrasonic cleaning time with anhydrous ethanol is 5-10 min. The ultrasonic cleaning time for deionized water is 5-10 minutes.

[0007] Furthermore, in S2, the volume ratio of deionized water: anhydrous ethanol: glycerol is 1:1:0.2-2.

[0008] Furthermore, in S3, the molar ratio of CoCl2·6H2O and FeCl2·4H2O is 2:1; The concentration of CoCl2·6H2O is 0.12 mol / L~0.15 mol / L; The concentration of FeCl2·4H2O is 0.06 mol / L to 0.075 mol / L.

[0009] Furthermore, in S4, the volume ratio of triethylamine to solution B is 1:3-10, and the sonication time is 10~30 s.

[0010] Furthermore, in S5, the reaction temperature is 200~240 °C and the reaction time is 24~48 h.

[0011] The basic cobalt chloride@cobalt iron spinel composite electrode prepared by the above method.

[0012] Furthermore, the basic cobalt chloride@cobalt iron spinel composite electrode is composed of basic cobalt chloride particles, cobalt iron spinel particles and a nickel mesh substrate, and both the basic cobalt chloride particles and the cobalt iron spinel particles are loaded on the nickel mesh substrate. Furthermore, the diameter of basic cobalt chloride particles is 10 nm to 20 nm; The diameter of cobalt-iron spinel particles is 100~300 nm.

[0013] The above-mentioned basic cobalt chloride@cobalt iron spinel composite electrode is used for the electrolysis of seawater to produce hydrogen.

[0014] The beneficial effects of the present invention are: (1) The preparation method of the present invention has the advantages of simple synthesis process and short operation cycle; (2) The basic cobalt chloride@cobalt-iron spinel composite electrode material prepared by this invention can be used as a highly active and stable anode catalyst for seawater electrolysis. By oxidizing cobalt-iron spinel with basic cobalt chloride, the catalyst activity is increased. At the same time, since cobalt-iron spinel has a stable octahedral structure, it can resist chlorine corrosion in seawater, prolong the catalytic stability, effectively reduce the overpotential of the seawater electrolysis reaction, and improve the service life of the electrode material for hydrogen production from seawater electrolysis. (3) The self-supporting basic cobalt chloride@cobalt iron spinel composite electrode prepared by the present invention is formed by heterogeneous nucleation growth of cobalt iron ion precipitation on the surface of nickel mesh during hydrothermal process. The self-supporting electrode structure is beneficial to increasing the specific surface area of ​​the active material and fully exposing the catalytic sites, thereby improving the catalytic activity of the electrode material. Attached Figure Description

[0015] Figure 1 This is a SEM image of the composite electrode in Comparative Example 1 of the present invention; Figure 2 This is a scanning electron microscope image of the basic cobalt chloride@cobalt iron spinel composite electrode in Example 1 of the present invention; Figure 3 This is the XRD data diagram of the basic cobalt chloride@cobalt iron spinel composite electrode in Example 1 of the present invention; Figure 4 This is a corrosion polarization curve of the basic cobalt chloride@cobalt iron spinel composite electrode in Example 1 of the present invention.

[0016] Figure 5 This is the LSV curve of the basic cobalt chloride@cobalt iron spinel composite electrode in Example 1 of the present invention; Figure 6 This is a diagram showing the stability of the basic cobalt chloride@cobalt iron spinel composite electrode used in seawater electrolysis in Example 1 of this invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through specific embodiments. The specific embodiments described in detail herein are merely illustrative of the invention and are not intended to limit its scope.

[0018] It should be noted that, unless otherwise specified, the experimental methods described in the following implementation scheme are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified.

[0019] The first aspect of this invention is to protect a method for preparing a basic cobalt chloride@cobalt-iron spinel composite electrode, comprising the following steps: S1. After cutting, the nickel mesh is ultrasonically cleaned sequentially with hydrochloric acid, anhydrous ethanol, and deionized water for a period of time to obtain the pretreated nickel mesh. The shape of the cut nickel mesh is not limited, such as a rectangle; the optimal cutting size is 1*2cm. 2 Optimal ultrasonic cleaning conditions are as follows: hydrochloric acid concentration 3 mol / L, ultrasonic cleaning time 10-20 min; anhydrous ethanol ultrasonic cleaning time 5-10 min; and deionized water ultrasonic cleaning time 5-10 min.

[0020] S2. A certain amount of deionized water, anhydrous ethanol, and glycerol are mixed to obtain solution A; wherein, by volume ratio, deionized water: anhydrous ethanol: glycerol = 1:1:0.2~2. Specifically, the volume ratio of deionized water, anhydrous ethanol, and glycerol can be 1:1:0.2, 1:1:0.4, 1:1:0.6, 1:1:0.8, 1:1:1, 1:1:1.2, 1:1:1.4, 1:1:1.6, 1:1:1.8, or 1:1:2.

[0021] S3. Weigh out certain amounts of CoCl2·6H2O and FeCl2·4H2O respectively and dissolve them in solution A to obtain solution B. Optimally, the molar ratio of CoCl2·6H2O to FeCl2·4H2O is 2:1. The concentration of CoCl2·6H2O in solution B is 0.12 mol / L to 0.15 mol / L. Optimal concentrations of CoCl2·6H2O can be 0.12 mol / L, 0.125 mol / L, 0.13 mol / L, 0.135 mol / L, 0.14 mol / L, 0.145 mol / L, or 0.15 mol / L. The optimal concentration of FeCl2·4H2O is 0.06 mol / L to 0.075 mol / L, with the best values ​​being 0.06 mol / L, 0.07 mol / L, and 0.075 mol / L.

[0022] S4. After adding the nickel mesh pretreated in S1 to solution B, add triethylamine and sonicate for a period of time to obtain suspension C. The optimal volume ratio of triethylamine to solution B is 1:3~10, which can be 1:3, 1:4, 1:5, 1:7, 1:9, or 1:10, and the sonication time is 10~30 s.

[0023] S5. The suspension C and the nickel mesh are placed together in a polytetrafluoroethylene stainless steel reactor and reacted at a temperature of 200~240 ℃ for 24~48 h to obtain a basic cobalt chloride@cobalt iron spinel composite electrode.

[0024] The second aspect of this invention is to protect the basic cobalt chloride@cobalt-iron spinel composite electrode obtained by the above preparation method. Furthermore, the obtained basic cobalt chloride@cobalt-iron spinel composite electrode is composed of basic cobalt chloride particles, cobalt-iron spinel particles, and a nickel mesh substrate. Both the basic cobalt chloride particles and the cobalt-iron spinel particles are loaded on the nickel mesh substrate. The diameter of the basic cobalt chloride particles is 10 nm to 20 nm; the diameter of the cobalt-iron spinel particles is 100 nm to 300 nm.

[0025] The third aspect of this invention is to protect the key application of the above-mentioned basic cobalt chloride@cobalt iron spinel composite electrode in the field of seawater electrolysis for hydrogen production.

[0026] <Comparative Example 1> A method for preparing a composite electrode includes the following steps: S1. Weigh out 0.0025 mol CoCl2·6H2O and 0.00125 mol FeCl2·4H2O respectively and dissolve them in 50 mL of deionized water to obtain solution B; S2. Add the nickel mesh to solution B, then add 1 mL of triethylamine, and sonicate for 30 s to obtain suspension C; S3. Add the suspension C and the nickel mesh together into a 100 mL polytetrafluoroethylene stainless steel reactor and react at 200 °C for 24 h to obtain the composite electrode.

[0027] After removing the composite electrode sheet, it was found that there was virtually no basic chloride or cobalt-iron spinel growing on the nickel mesh (e.g. Figure 1 (As shown).

[0028] <Example 1> S1. Cut the nickel mesh into 1*2 cm pieces. 2 After forming a rectangle, the nickel mesh was ultrasonically cleaned for 20 min with 3 mol / L hydrochloric acid, 5 min with anhydrous ethanol, and 5 min with deionized water to obtain a cleaned nickel mesh. S2. Mix 20 mL of deionized water, 20 mL of anhydrous ethanol and 10 mL of glycerol to obtain solution A; S3. Weigh out 0.0025 mol CoCl2·6H2O and 0.00125 mol FeCl2·4H2O respectively and dissolve them in solution A to obtain solution B; S4. Add the cleaned nickel mesh to solution B, then add 10 mL of triethylamine, and sonicate for 30 s to obtain suspension C. S5. Add the suspension C and the cleaned nickel mesh together into a 100 mL polytetrafluoroethylene stainless steel reactor, and react at 200 °C for 24 h to obtain a basic cobalt chloride@cobalt iron spinel composite electrode.

[0029] Scanning electron microscope (SEM) images of the basic cobalt chloride@cobalt iron spinel composite electrode prepared in this embodiment were obtained respectively. Figure 2 ) and XRD ( Figure 3 The results showed diffraction peaks for both basic cobalt chloride and cobalt-iron spinel, indicating the formation of the composite material structure.

[0030] The corrosion polarization curve of the basic cobalt chloride@cobalt iron spinel composite electrode prepared in this embodiment is as follows: Figure 4 As shown, its corrosion potential (0.01 V) is higher than that of the cobalt-iron spinel electrode (-0.21 V) and the basic cobalt chloride electrode (-0.11 V), indicating an improvement in corrosion resistance.

[0031] Electrocatalytic performance testing of basic cobalt chloride@cobalt-iron spinel composite electrode: In the seawater oxidation electrocatalytic performance test, the basic cobalt chloride@cobalt-iron spinel composite electrode achieved a performance of 100 mA / cm². 2 Under these conditions, the overpotential is only 295 mV (e.g. Figure 5 As shown), it is higher than that of commercial ruthenium dioxide electrodes (396 mV). And at 100 mA / cm²... 2 Under certain conditions, it can continuously and stably catalytically electrolyze seawater for more than 100 hours, indicating its good stability (e.g., Figure 6 (As shown).

[0032] <Example 2> S1. Cut the nickel mesh into 1*2 cm pieces. 2 After forming a rectangle, the nickel mesh was ultrasonically cleaned for 20 min with 3 mol / L hydrochloric acid, 5 min with anhydrous ethanol, and 5 min with deionized water to obtain a cleaned nickel mesh. S2. Mix 10 mL of deionized water, 10 mL of anhydrous ethanol and 20 mL of glycerol to obtain solution A; S3. Weigh out 0.0025 mol CoCl2·6H2O and 0.00125 mol FeCl2·4H2O respectively and dissolve them in solution A to obtain solution B; S4. Add the cleaned nickel mesh to solution B, then add 10 mL of triethylamine, and sonicate for 30 s to obtain suspension C. S5. Add the suspension C and the cleaned nickel mesh together into a 100 mL polytetrafluoroethylene stainless steel reactor, and react at 200 °C for 24 h to obtain a basic cobalt chloride@cobalt iron spinel composite electrode.

[0033] The basic cobalt chloride@cobalt-iron spinel composite electrode prepared in this embodiment operates at 100 mA / cm². 2 Under certain conditions, the overpotential is 298 mV, indicating good electrocatalytic seawater oxidation performance.

[0034] <Example 3> S1. Cut the nickel mesh into 1*2 cm pieces. 2 After forming a rectangle, the nickel mesh was ultrasonically cleaned for 20 min with 3 mol / L hydrochloric acid, 5 min with anhydrous ethanol, and 5 min with deionized water to obtain a cleaned nickel mesh. S2. Mix 20 mL of deionized water, 20 mL of anhydrous ethanol and 10 mL of glycerol to obtain solution A; S3. Weigh out 0.0025 mol CoCl2·6H2O and 0.00125 mol FeCl2·4H2O respectively and dissolve them in solution A to obtain solution B; S4. Add the cleaned nickel mesh to solution B, then add 5 mL of triethylamine, and sonicate for 30 s to obtain suspension C; S5. Add the suspension C and the cleaned nickel mesh together into a 100 mL polytetrafluoroethylene stainless steel reactor, and react at 200 °C for 24 h to obtain a basic cobalt chloride@cobalt iron spinel composite electrode.

[0035] The basic cobalt chloride@cobalt-iron spinel composite electrode prepared in this embodiment operates at 100 mA / cm². 2 Under certain conditions, the overpotential is 299 mV, indicating good electrocatalytic seawater oxidation performance.

[0036] <Example 4> S1. Cut the nickel mesh into 1*2 cm pieces. 2 After forming a rectangle, the nickel mesh was ultrasonically cleaned for 20 min with 3 mol / L hydrochloric acid, 5 min with anhydrous ethanol, and 5 min with deionized water to obtain a cleaned nickel mesh. S2. Mix 20 mL of deionized water, 20 mL of anhydrous ethanol and 10 mL of glycerol to obtain solution A; S3. Weigh out 0.0025 mol CoCl2·6H2O and 0.00125 mol FeCl2·4H2O respectively and dissolve them in solution A to obtain solution B; S4. Add the cleaned nickel mesh to solution B, then add 10 mL of triethylamine, and sonicate for 30 s to obtain suspension C. S5. Add the suspension C and the cleaned nickel mesh together into a 100 mL polytetrafluoroethylene stainless steel reactor, and react at 240 °C for 48 h to obtain a basic cobalt chloride@cobalt iron spinel composite electrode.

[0037] The basic cobalt chloride@cobalt-iron spinel composite electrode prepared in this embodiment operates at 100 mA / cm². 2 Under certain conditions, the overpotential is 296 mV, indicating good electrocatalytic seawater oxidation performance.

[0038] Where there is no conflict, the above embodiments and features described herein can be combined with each other.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a basic cobalt chloride@cobalt-iron spinel composite electrode, characterized in that, Includes the following steps: S1. Pre-treat the nickel mesh; S2. A solution A is obtained by mixing a certain amount of deionized water, anhydrous ethanol and glycerol. S3. Weigh out a certain amount of CoCl2·6H2O and FeCl2·4H2O respectively and dissolve them in solution A to obtain solution B; S4. After adding the nickel mesh pretreated in S1 to solution B, add triethylamine and sonicate for a period of time to obtain suspension C. S5. After the suspension C and the nickel mesh are reacted under certain temperature conditions for a period of time, the basic cobalt chloride@cobalt iron spinel composite electrode is obtained.

2. The method for preparing the basic cobalt chloride@cobalt-iron spinel composite electrode according to claim 1, characterized in that, In S1, the pretreatment process of the nickel mesh is as follows: after cutting the nickel mesh, it is ultrasonically cleaned with hydrochloric acid, anhydrous ethanol and deionized water for a period of time in sequence to obtain the treated nickel mesh.

3. The method for preparing the basic cobalt chloride@cobalt-iron spinel composite electrode according to claim 2, characterized in that, In S1, the concentration of hydrochloric acid is 3 mol / L, and the time condition for ultrasonic cleaning with hydrochloric acid is 10-20 min; The ultrasonic cleaning time with anhydrous ethanol is 5-10 min. The ultrasonic cleaning time for deionized water is 5-10 minutes.

4. The method for preparing the basic cobalt chloride@cobalt-iron spinel composite electrode according to claim 1, characterized in that, In S2, the volume ratio of deionized water: anhydrous ethanol: glycerol is 1:1:0.2~2.

5. The method for preparing the basic cobalt chloride@cobalt-iron spinel composite electrode according to claim 1, characterized in that, In S3, the molar ratio of CoCl2·6H2O and FeCl2·4H2O is 2:

1. The concentration of CoCl2·6H2O is 0.12 mol / L~0.15 mol / L; The concentration of FeCl2·4H2O is 0.06 mol / L to 0.075 mol / L.

6. The method for preparing the basic cobalt chloride@cobalt-iron spinel composite electrode according to claim 1, characterized in that, In S4, the volume ratio of triethylamine to solution B is 1:3~10, and the sonication time is 10~30 s.

7. The method for preparing the basic cobalt chloride@cobalt-iron spinel composite electrode according to claim 1, characterized in that, In S5, the reaction temperature is 200~240 ℃ and the reaction time is 24~48 h.

8. The basic cobalt chloride@cobalt iron spinel composite electrode prepared by the preparation method according to any one of claims 1-7.

9. The basic cobalt chloride@cobalt-iron spinel composite electrode according to claim 8, characterized in that, The basic cobalt chloride@cobalt iron spinel composite electrode is composed of basic cobalt chloride particles, cobalt iron spinel particles and a nickel mesh substrate, with both the basic cobalt chloride particles and the cobalt iron spinel particles loaded on the nickel mesh substrate. Furthermore, the diameter of basic cobalt chloride particles is 10 nm to 20 nm; The diameter of cobalt-iron spinel particles is 100~300 nm.

10. The application of the basic cobalt chloride@cobalt iron spinel composite electrode for seawater electrolysis to produce hydrogen according to claim 9.

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