Preparation method of iridium ruthenium alloy catalyst for PEM electrolytic water hydrogen production

Abstract

The present invention relates to a preparation method of an iridium-ruthenium alloy catalyst for PEM electrolytic water hydrogen production. The preparation method comprises the following steps: Step 1): Dissolve an iridium precursor in deionized water, and then add an alkaline solution to the iridium precursor solution, and heat and stir; Step 2): Adjust the pH of the solution obtained in step (1) to 1-6, filter and wash to obtain a solid powder; Step 3): Disperse the solid powder in a reducing agent solution to obtain solution A; then dissolve ruthenium chloride in the reducing agent solution to obtain solution B; add solution B to solution A under stirring to obtain solution C; add a dispersant solution to solution C and stir evenly, and then add sodium acetate trihydrate and stir evenly; Step 4): Heat and stir the mixed solution in an oil bath, filter and wash, and finally dry to obtain a solid powder of the iridium-ruthenium alloy. The iridium-ruthenium alloy catalyst prepared by the present invention exhibits high catalytic activity and stability, and has good application prospects in PEM electrolytic water hydrogen production.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalyst preparation methods, and more particularly to the technical field of a preparation method of an iridium-ruthenium alloy catalyst for PEM water electrolysis hydrogen production. Background Art

[0002] Hydrogen is one of the most promising clean energy carriers, and one of the most effective and environmentally friendly ways to produce hydrogen is electrochemical water splitting. PEM-based water electrolysis has the advantages of compact design, simplicity, rapid response, low ohmic loss, high voltage efficiency, and high gas purity. As a half-reaction, the oxygen evolution reaction (OER) plays a key role in PEM water electrolysis. Among them, ruthenium (Ru) and iridium (Ir)-based materials have excellent HER and OER performance. Ru-based catalysts usually have high electrochemical activity and stability in alkaline solutions, but are easily corroded under acidic conditions. On the contrary, although Ir-based materials can effectively reduce the degree of corrosion and significantly improve stability, due to their high overpotential, they still cannot meet the needs of actual PEM water electrolysis hydrogen production. Therefore, they are usually not ideal catalysts for electrochemical reactions. To solve the above problems, by strategies such as metal doping, hierarchical structure preparation, or alloying, developing Ru-based and Ir-based catalysts with enhanced activity and stability is expected to achieve both high activity and high stability.

[0003] Alloy catalysts utilize the synergistic effect between metals to enhance electron transfer and shorten the diffusion distance, which is one of the effective methods to obtain high catalytic activity and high stability water electrolysis catalysts. Currently, the commonly used preparation methods of IrRu alloy catalysts all require high-temperature heat treatment. However, during the high-temperature heat treatment process, the active metal particles of Ir and Ru are extremely easy to agglomerate, resulting in a decrease in the activity and stability of the alloy catalyst. Therefore, providing a preparation method of an IrRu alloy catalyst that does not require high-temperature heat treatment, avoiding the agglomeration of active metal particles, making the active metal particles in the alloy catalyst evenly dispersed, and achieving high activity and high stability of the alloy catalyst.

[0004] Overview of the defects of the prior art:

[0005] 1. The IrRu alloy catalysts synthesized by the above methods are prone to agglomeration and have relatively large particles.

[0006] 2. The IrRu alloy catalysts synthesized by the above methods have a relatively high overpotential for water electrolysis, which affects the performance of the electrolytic cell. Summary of the Invention

[0007] The present invention precisely aims to solve the above problems and deficiencies, and provides a preparation method of an iridium-ruthenium alloy catalyst for PEM electrolytic water hydrogen production. In the present invention, hydrated iridium oxide solid powder is obtained under alkaline conditions, and then an IrRu alloy catalyst is obtained by reduction using an alcohol + alcohol or alcohol + water mixed system. At the same time, sodium acetate is used as a morphology control agent to better disperse metal particles.

[0008] The present invention is realized by adopting the following technical solutions.

[0009] A preparation method of an iridium-ruthenium alloy catalyst for PEM electrolytic water hydrogen production, the preparation method of the present invention includes the following steps:

[0010] Step 1) Dissolve an iridium precursor in deionized water, stir evenly, then add an alkaline solution to the iridium precursor solution, adjust the pH to 9 - 13, then heat and stir the obtained solution in an oil bath, and then naturally cool to room temperature;

[0011] Step 2) Use an acid solution to adjust the pH of the solution obtained in step (1) to 1 - 6, stir overnight, and then filter and wash to obtain a solid powder;

[0012] Step 3) Disperse the solid powder obtained in step (2) in a reducing agent solution to obtain solution A;

[0013] Then dissolve ruthenium chloride in the reducing agent solution to obtain solution B;

[0014] Under stirring conditions, slowly add solution B to solution A to obtain solution C;

[0015] Add a dispersant solution to solution C, stir evenly, and then add sodium acetate trihydrate and stir evenly;

[0016] Step 4) Heat and stir the mixed solution obtained in step (3) in an oil bath, and then naturally cool to room temperature; filter and wash, and finally vacuum dry to obtain a solid powder of an iridium-ruthenium alloy.

[0017] Furthermore, the iridium precursor in step 1) of the present invention is iridium chlorate or iridium trichloride or iridium acetate.

[0018] Furthermore, the alkaline solution in step 1) of the present invention is sodium carbonate solution or sodium hydroxide or potassium hydroxide solution.

[0019] Furthermore, the oil bath temperature in step 1) of the present invention is 80 - 120 °C.

[0020] Furthermore, the acid solution in step 2) of the present invention is nitric acid or sulfuric acid.

[0021] Furthermore, the reducing agent in step 3) of the present invention is methanol or ethanol or ethylene glycol or isopropanol or glycerol; the dispersant in step 3) is isopropanol or water or ethylene glycol or ethanol.

[0022] Furthermore, the combination of the reducing agent and the dispersant in step 3) of the present invention is: methanol + isopropanol or methanol + ethylene glycol or ethylene glycol + isopropanol or methanol + water or methanol + ethanol or isopropanol + water or ethylene glycol + water.

[0023] Furthermore, the vacuum drying temperature in step 4) of the present invention is 60 °C.

[0024] Furthermore, the drying time in step 4) of the present invention is 12 hours.

[0025] Furthermore, the oil bath temperature in step 4) of the present invention is 60 °C - 160 °C.

[0026] The beneficial effects of the present invention are as follows: 1. By obtaining hydrated iridium oxide solid powder under alkaline conditions first, then using methanol and isopropanol simultaneously as the reducing agent and the dispersant, and sodium acetate as the morphology control agent, the iridium ruthenium alloy catalyst is synthesized without high-temperature heat treatment, avoiding the agglomeration of active metal particles.

[0027] 2. The iridium ruthenium alloy catalyst prepared by the present invention for hydrogen production by electrolyzing water shows high catalytic activity and stability in acidic electrolyte, with an overpotential reaching 223 mV, and at the same time has an ultra-high electrochemically active area and a low Tafel slope, having good application prospects in PEM electrolytic water hydrogen production.

[0028] The present invention will be further explained below in conjunction with the drawings and specific embodiments. Description of the Drawings

[0029] Figure 1 It is the TEM diagram of the iridium ruthenium alloy catalyst of the present invention;

[0030] Figure 2 It is the XRD curve of the iridium ruthenium alloy catalyst obtained in Example 1 of the present invention;

[0031] Figure 3 It is the oxygen evolution curve of the iridium ruthenium alloy catalysts obtained in Examples 1 - 7 of the present invention;

[0032] Figure 4 It is the stability curve of the iridium ruthenium alloy catalyst obtained in Example 1 of the present invention. Specific Embodiments

[0033] A preparation method of an iridium ruthenium alloy catalyst for PEM electrolytic water hydrogen production, the preparation method of the present invention includes the following steps:

[0034] Step 1) Dissolve the iridium precursor in deionized water, stir evenly, then add the alkaline solution to the iridium precursor solution, adjust the pH to 9 - 13, then heat and stir the obtained solution in an oil bath, and then naturally cool it to room temperature;

[0035] Step 2) Use an acid solution to adjust the pH of the solution obtained in step (1) to 1 - 6, and stir overnight, then filter and wash to obtain a solid powder;

[0036] Step 3) Disperse the solid powder obtained in step (2) in a reducing agent solution to obtain solution A;

[0037] Then dissolve ruthenium chloride in the reducing agent solution to obtain solution B;

[0038] Slowly add solution B to solution A under stirring to obtain solution C;

[0039] Add a dispersant solution to solution C and stir evenly, then add sodium acetate trihydrate and stir evenly;

[0040] Step 4) Heat and stir the mixed solution obtained in step (3) in an oil bath, and then naturally cool it to room temperature; filter and wash, and finally vacuum dry to obtain a solid powder of iridium ruthenium alloy.

[0041] Furthermore, the iridium precursor in step 1) of the present invention is chloroiridic acid or iridium trichloride or iridium acetate.

[0042] Furthermore, the alkaline solution in step 1) of the present invention is sodium carbonate solution or sodium hydroxide or potassium hydroxide solution.

[0043] Furthermore, the oil bath temperature in step 1) of the present invention is 80 - 120 °C.

[0044] Furthermore, the acid solution in step 2) of the present invention is nitric acid or sulfuric acid.

[0045] Furthermore, the reducing agent in step 3) of the present invention is methanol or ethanol or ethylene glycol or isopropanol or glycerol; the dispersant in step 3) is isopropanol, water, ethylene glycol, ethanol.

[0046] Furthermore, the combination of the reducing agent and the dispersant in step 3) of the present invention is: methanol + isopropanol or methanol + ethylene glycol or ethylene glycol + isopropanol or methanol + water or methanol + ethanol or isopropanol + water or ethylene glycol + water.

[0047] Furthermore, the vacuum drying temperature in step 4) of the present invention is 60 °C.

[0048] Furthermore, the drying time in step 4) of the present invention is 12 hours.

[0049] Furthermore, the oil bath temperature in step 4) of the present invention is 60°C - 160°C.

[0050] A preparation method of an iridium-ruthenium alloy catalyst for PEM electrolytic water hydrogen production specifically comprises the following steps:

[0051] Step 1) Dissolve the iridium precursor in deionized water, stir evenly, then add the 2M / L sodium carbonate solution to the iridium precursor solution at a rate of 2 ml / min, adjust the pH to 10, then heat and stir the obtained solution in an oil bath at 90°C for 1 h, and then naturally cool to room temperature;

[0052] Step 2) Use the HNO3 solution to adjust the pH of the solution obtained in step (1) to 1, stir overnight at this pH, and then filter and wash to obtain a solid powder;

[0053] Step 3) Disperse the solid powder obtained in step (2) in a methanol solution to obtain solution A, then dissolve ruthenium chloride in the methanol solution to obtain solution B, and slowly add solution B to solution A under stirring to obtain solution C; add an isopropanol solution to solution C and stir evenly, and then add a certain amount of sodium acetate trihydrate and stir evenly;

[0054] Step 4) Heat and stir the mixed solution obtained in step (3) in an oil bath at 80°C for 5 h, and then naturally cool to room temperature; filter and wash with a mixed solution of ethanol and water, and finally vacuum dry at 60°C for 12 h to obtain a solid powder of the iridium-ruthenium alloy.

[0055] See Figure 1 , Figure 2 , Figure 3 , Figure 4 as shown.

[0056] Optimal experimental conditions:

[0057] (1) Dissolve 1 ml of 0.1M / L iridium precursor in 15 ml of deionized water, stir evenly, then add the 2M / L sodium carbonate solution to the iridium precursor solution at a rate of 1 ml / min, adjust the pH to 10, then heat and stir the obtained solution in an oil bath at 90°C for 1 h, and naturally cool to room temperature;

[0058] (2) Use 1M / L HNO3 solution to adjust the pH of the solution obtained in step (1) to 1, stir overnight at this pH, and then filter and wash to obtain a solid powder;

[0059] (3) Disperse the solid powder obtained in step (2) in 5 ml of methanol solution to obtain solution A. Then, dissolve 19 mg of ruthenium chloride in 5 ml of methanol solution to obtain solution B. Slowly add solution B to solution A under stirring to obtain solution C. Add 10 ml of isopropanol solution to solution C and stir evenly, and then add 130 mg of sodium acetate trihydrate and stir evenly.

[0060] (4) Heat and stir the mixed solution obtained in step (3) in an 80 °C oil bath for 5 h, and then naturally cool to room temperature; filter and wash with a mixed solution of ethanol and water, and finally dry in vacuo at 60 °C for 12 h to obtain a solid powder of iridium ruthenium alloy.

[0061] Preferred condition parameter details:

[0062] In step (1):

[0063] Iridium precursor: chloroiridic acid, iridium trichloride, iridium acetate

[0064] Alkaline solution: sodium carbonate solution, sodium hydroxide, potassium hydroxide solution

[0065] pH: 9 - 13

[0066] Heating temperature: 80 - 120 °C

[0067] In step (2)

[0068] Acid: nitric acid, sulfuric acid

[0069] pH: 1 - 6

[0070] In step (3)

[0071] Reducing agent: methanol, ethanol, ethylene glycol, isopropanol, glycerol

[0072] Dispersant: isopropanol, water, ethylene glycol, ethanol

[0073] In step (4)

[0074] Reduction temperature: 60 °C - 160 °C

[0075] Some examples of the present invention are shown in Table 1:

[0076] Table 1 Comparison table of conditions and experimental results of some examples of the present invention

[0077]

[0078] The above are only some specific embodiments of the present invention (since the present invention includes a numerical range, the embodiments cannot be exhausted, and the protection scope recorded in the present invention includes the numerical range of the present invention and the scope of other technical points). The specific content or common knowledge known in the solution is not described in detail here (including but not limited to abbreviations, contractions, and units commonly used in the art). It should be noted that the above embodiments do not limit the present invention in any way. For those skilled in the art, any technical solutions obtained by means of equivalent substitution or equivalent transformation fall within the protection scope of the present invention. The protection scope claimed in this application shall be subject to the content of its claims, and the specific implementation manners and the like recorded in the specification can be used to interpret the content of the claims.

Claims

1. A preparation method of an iridium-ruthenium alloy catalyst for PEM electrolytic water hydrogen production, characterized in that The preparation method includes the following steps: Step 1) Dissolve the iridium precursor in deionized water, stir evenly, then add the alkaline solution to the iridium precursor solution, adjust the pH to 9 - 13, then heat and stir the obtained solution in an oil bath, and then naturally cool it to room temperature; Step 2) Use an acid solution to adjust the pH of the solution obtained in step (1) to 1 - 6, and then filter and wash to obtain a solid powder; Step 3) Disperse the solid powder obtained in step (2) in a reducing agent solution to obtain solution A; Then dissolve ruthenium chloride in the reducing agent solution to obtain solution B; Slowly add solution B to solution A under stirring conditions to obtain solution C; Add a dispersant solution to solution C, stir evenly, and then add sodium acetate trihydrate and stir evenly; Step 4) Heat and stir the mixed solution obtained in step (3) in an oil bath, and then naturally cool it to room temperature; filter and wash, and finally vacuum dry to obtain a solid powder of the iridium alloy.

2. The preparation method of an iridium-ruthenium alloy catalyst for PEM electrolytic water hydrogen production according to claim 1, wherein, The iridium precursor in step 1) is iridium chloride or iridium trichloride or iridium acetate.

3. The preparation method of an iridium-ruthenium alloy catalyst for PEM electrolytic water hydrogen production according to claim 1, characterized in that, The alkaline solution in step 1) is sodium carbonate solution or sodium hydroxide or potassium hydroxide solution.

4. The preparation method of an iridium-ruthenium alloy catalyst for PEM electrolytic water hydrogen production according to claim 1, characterized in that, The oil bath temperature in step 1) is 80 - 120 °C.

5. The preparation method of an iridium-ruthenium alloy catalyst for PEM electrolytic water hydrogen production according to claim 1, characterized in that, The acid solution in step 2) is nitric acid or sulfuric acid.

6. The preparation method of an iridium-ruthenium alloy catalyst for PEM electrolytic water hydrogen production according to claim 1, characterized in that, The reducing agent in step 3) is methanol or ethanol or ethylene glycol or isopropyl alcohol or glycerol; the dispersant in step 3) is isopropyl alcohol or water or ethylene glycol or ethanol.

7. The preparation method of an iridium-ruthenium alloy catalyst for PEM electrolytic water hydrogen production according to claim 6, characterized in that, The combinations of the reducing agent and the dispersant in step 3) are: methanol + isopropyl alcohol or methanol + ethylene glycol or ethylene glycol + isopropyl alcohol or methanol + water or methanol + ethanol or isopropyl alcohol + water or ethylene glycol + water.

8. The preparation method of an iridium-ruthenium alloy catalyst for PEM electrolytic water hydrogen production according to claim 1, characterized in that, The vacuum drying temperature in step 4) is 60 °C.

9. The preparation method of an iridium-ruthenium alloy catalyst for PEM electrolytic water hydrogen production according to claim 1, characterized in that, The drying time in step 4) is 12 hours.

10. The preparation method of an iridium-ruthenium alloy catalyst for PEM electrolytic water hydrogen production according to claim 1, characterized in that, The oil bath temperature in step 4) is 60 °C - 160 °C.

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