Hydrogen evolution electrode and preparation method thereof

Abstract

The invention provides a hydrogen evolution electrode and a preparation method thereof, and belongs to the technical field of electrode preparation. The invention provides a preparation method of a hydrogen evolution electrode, which comprises the following steps: mixing a nickel net coated with a Raney nickel coating with a strong alkali solution for oxidation reaction, and removing aluminum in the Raney nickel coating to obtain a nickel net with a Raney nickel porous coating; mixing the nickel net with the Raney nickel porous coating with a solution containing a noble metal salt and / or a noble metal complex, carrying out a replacement reaction, reducing noble metal ions into metal elementary substances, loading the metal elementary substances on the Raney nickel porous coating, and obtaining a hydrogen evolution electrode precursor; and carrying out heat treatment on the hydrogen evolution electrode precursor to obtain the hydrogen evolution electrode. The activity of the hydrogen evolution electrode is improved by enlarging the specific surface area of the nickel net; the binding force between the precious metal and the coating is improved through heat treatment, so that the precious metal is not prone to falling off, and the activity of the hydrogen evolution electrode is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electrode preparation, and in particular to a hydrogen evolution electrode and a preparation method thereof. Background Art

[0002] Alkaline water electrolysis (ALK) has the characteristics of high technical maturity and low large-scale manufacturing cost. It is considered to be the best route for developing hydrogen energy by coupling with wind and solar power generation technology.

[0003] At present, the core components of commercial alkaline water electrolysis hydrogen production equipment are still mainly traditional nickel-based hydrogen evolution electrodes, including woven nickel wire mesh, nickel foam, etc., with low manufacturing costs. In actual application, the current density can only reach 2000-3000A / m 2 This makes it impossible to further effectively increase the current density of the electrolyzer in the final assembly process, and the material input for a single stack is too large. In addition, by linearly increasing the amount of materials used and improving the technical indicators of a single stack, not only the transportation and installation costs of the equipment are increased, but also the structural stability of the equipment is greatly improved, causing serious safety problems.

[0004] Therefore, in order to solve the technical problems of the industry development, it is necessary to develop electrodes with higher hydrogen evolution activity. Theoretically, precious metals such as platinum, palladium, and ruthenium have higher hydrogen evolution catalytic activity, so the modification of hydrogen evolution electrodes by precious metals has become an important trend in the development of the industry. For example, the electrochemical co-deposition method is used to co-deposit nickel and precious metals on the carrier surface, but the activity of the prepared electrode still needs to be improved. Summary of the invention

[0005] The object of the present invention is to provide a hydrogen evolution electrode and a preparation method thereof. The hydrogen evolution electrode provided by the present invention has high activity.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing a hydrogen evolution electrode, comprising the following steps:

[0008] The nickel mesh coated with the Raney nickel coating is mixed with a strong alkaline solution to undergo an oxidation reaction to remove aluminum in the Raney nickel coating to obtain a nickel mesh with a Raney nickel porous coating;

[0009] The nickel mesh having the Raney nickel porous coating is mixed with a solution containing a noble metal salt and / or a noble metal complex to carry out a replacement reaction, and the noble metal ions are reduced to metal elements and loaded onto the Raney nickel porous coating to obtain a hydrogen evolution electrode precursor;

[0010] The hydrogen evolution electrode precursor is subjected to heat treatment to obtain the hydrogen evolution electrode.

[0011] Preferably, the mass ratio of nickel to aluminum in the Raney nickel coating is 1:0.2-1.8.

[0012] Preferably, the solution containing a noble metal salt and / or a noble metal complex further comprises an auxiliary agent.

[0013] Preferably, the auxiliary agent includes one or more of hydrochloric acid, citric acid and polyvinyl pyrrolidone.

[0014] Preferably, the noble metal includes one or more of platinum, palladium and ruthenium.

[0015] Preferably, the ratio of the volume of the solution containing the noble metal salt and / or the noble metal complex to the area of ​​the nickel mesh having the Raney nickel porous coating is 1 to 3 mL / cm 2 .

[0016] Preferably, the temperature of the replacement reaction is 25-80° C. and the time is 0.5-10 h.

[0017] Preferably, the heat treatment temperature is 350-650° C. and the time is 1-5 hours.

[0018] The present invention also provides a hydrogen evolution electrode prepared by the preparation method described in the above scheme, comprising a nickel mesh with a Raney nickel porous coating; the Raney nickel porous coating is loaded with a noble metal.

[0019] Preferably, the loading amount of the noble metal is 0.05 to 1 mg / cm 2 .

[0020] The present invention provides a method for preparing a hydrogen evolution electrode, comprising the following steps: mixing a nickel mesh coated with a Raney nickel coating with a strong alkaline solution for oxidation reaction, removing aluminum in the Raney nickel coating, and obtaining a nickel mesh with a Raney nickel porous coating; mixing the nickel mesh with the Raney nickel porous coating with a solution containing a noble metal salt and / or a noble metal complex for replacement reaction, reducing the noble metal ions to metal elements and loading them onto the Raney nickel porous coating, and obtaining a hydrogen evolution electrode precursor; and heat treating the hydrogen evolution electrode precursor to obtain the hydrogen evolution electrode. The present invention selects a nickel mesh coated with a Raney nickel coating as a substrate, and forms a porous structure by removing aluminum in the Raney nickel coating, thereby expanding the specific surface area of ​​the nickel mesh, thereby improving the activity of the hydrogen evolution electrode; in addition, the present invention improves the bonding force between the noble metal and the coating by heat treatment, so that the noble metal is not easy to fall off, and further improves the activity of the hydrogen evolution electrode.

[0021] In addition, the preparation method of the invention is simple, and batch production can be easily realized, with less emission pollution and simple wastewater treatment process. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1The process flow chart of preparing a hydrogen evolution electrode according to an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of an electrolytic cell according to an embodiment of the present invention;

[0024] Figure 3 It is a front view of a simulated mastoid plate in an electrolytic cell according to an embodiment of the present invention;

[0025] Figure 4 Polarization curves of the nickel mesh coated with Raney nickel coating and the hydrogen evolution electrodes of Examples 1 to 3 according to the present invention. DETAILED DESCRIPTION

[0026] The present invention provides a method for preparing a hydrogen evolution electrode, comprising the following steps:

[0027] The nickel mesh coated with the Raney nickel coating is mixed with a strong alkaline solution to perform an oxidation reaction to remove aluminum in the Raney nickel coating to obtain a nickel mesh with a Raney nickel porous coating;

[0028] The nickel mesh having the Raney nickel porous coating is mixed with a solution containing a noble metal salt and / or a noble metal complex to carry out a replacement reaction, and the noble metal ions are reduced to metal elements and loaded onto the Raney nickel porous coating to obtain a hydrogen evolution electrode precursor;

[0029] The hydrogen evolution electrode precursor is subjected to heat treatment to obtain the hydrogen evolution electrode.

[0030] The invention mixes a nickel mesh coated with a Raney nickel coating with a strong alkali solution to carry out an oxidation reaction, removes aluminum in the Raney nickel coating, and obtains a nickel mesh with a Raney nickel porous coating.

[0031] In the present invention, the coating method preferably includes spraying; and the nickel mesh is preferably subjected to sandblasting before spraying. Sandblasting can improve the adhesion strength of the coating.

[0032] In the present invention, the mesh number of the nickel mesh is preferably 40 to 50 meshes, and the wire diameter is preferably 0.1 to 0.5 mm.

[0033] Before the nickel mesh coated with the Raney nickel coating is mixed with the strong alkaline solution, the nickel mesh coated with the Raney nickel coating is preferably cut and shaped according to product requirements.

[0034] In the present invention, the mass ratio of nickel to aluminum in the Raney nickel coating is preferably 1:0.2-1.8, more preferably 1:0.5-1.5, further preferably 1:0.8-1.2, the purity of nickel is preferably 95-100%, and the purity of aluminum is preferably 95-100%.

[0035] In the present invention, the cutting and forming method preferably includes laser cutting and / or water jet cutting; the power of the laser cutting is preferably 1500-3000W.

[0036] In the present invention, the weight of the Raney nickel coating in the nickel mesh is 100 to 300 g / m 2 , more preferably 150 to 250 g / m 2 , more preferably 180 to 200 g / m 2 .

[0037] In the present invention, the mixing method preferably includes impregnation.

[0038] In the present invention, the strong alkali solution preferably includes potassium hydroxide solution and / or sodium hydroxide solution, and the mass concentration is preferably 10-30%. During the oxidation reaction, the strong alkali solution reacts with the aluminum in the Raney nickel coating to generate water-soluble salts, which can increase the porosity of the coating.

[0039] In the present invention, the oxidation reaction time is preferably 3 hours.

[0040] After obtaining the nickel mesh with the Raney nickel porous coating, the present invention mixes the nickel mesh with the Raney nickel porous coating with a solution containing a noble metal salt and / or a noble metal complex to carry out a replacement reaction, and reduces the noble metal ions to metal elements and loads them onto the Raney nickel porous coating to obtain a hydrogen evolution electrode precursor.

[0041] In the present invention, the ratio of the volume of the solution containing the noble metal salt and / or the noble metal complex to the area of ​​the nickel mesh having the Raney nickel porous coating is preferably 1 to 3 mL / cm 2 , more preferably 1.5 to 2 mL / cm 2 The total concentration of the noble metal salt and / or noble metal complex in the solution containing the noble metal salt and / or noble metal complex is preferably 0.1-1 mg / mL, more preferably 0.2-0.8 mg / mL, and further preferably 0.4-0.6 mg / mL; the noble metal includes one or more of platinum, palladium and ruthenium. In the present invention, the noble metal complex preferably includes chloroplatinic acid.

[0042] In the present invention, the solution containing a noble metal salt and / or a noble metal complex preferably includes an auxiliary agent; the auxiliary agent preferably includes one or more of hydrochloric acid, citric acid and polyvinyl pyrrolidone. When the auxiliary agent is hydrochloric acid, the pH value of the solution containing a noble metal salt and / or a noble metal complex is preferably 2 to 3. Hydrochloric acid can regulate the speed of the replacement reaction.

[0043] In the present invention, the temperature of the replacement reaction is preferably 25 to 80° C., more preferably 40 to 60° C., and further preferably 45 to 50° C.; the time is preferably 0.5 to 10 hours, more preferably 2 to 8 hours, and further preferably 4 to 6 hours. During the replacement reaction, the noble metal ions undergo a replacement reaction with nickel to generate a metal element.

[0044] After obtaining the hydrogen evolution electrode precursor, the present invention performs heat treatment on the hydrogen evolution electrode precursor to obtain the hydrogen evolution electrode.

[0045] In the present invention, the temperature of the heat treatment is preferably 350-650°C, more preferably 400-600°C, and further preferably 450-500°C; the time is preferably 1-5h, and more preferably 2-4h. In the present invention, the heat treatment is preferably carried out in an annealing furnace, a trolley furnace or a kiln. The electrode after the noble metal deposition is subjected to high temperature annealing treatment to form a metal structure with a stable surface structure, and the noble metal elements form a strong bonding force with the coating surface.

[0046] The present invention also provides a hydrogen evolution electrode prepared by the preparation method described in the above scheme, comprising a nickel mesh with a Raney nickel porous coating; the Raney nickel porous coating is loaded with noble metals and / or noble metal oxides.

[0047] In the present invention, the loading amount of the noble metal element is preferably 0.05 to 1 mg / cm 2 .

[0048] The process flow chart of preparing the hydrogen evolution electrode according to the embodiment of the present invention is as follows: Figure 1 As shown: After spraying Raney nickel on the nickel mesh, cutting, activation, deposition of precious metals and high-temperature heat treatment are carried out in sequence to obtain a hydrogen evolution electrode.

[0049] The hydrogen evolution electrode and the preparation method thereof provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0050] Example 1

[0051] A 46-mesh woven nickel wire mesh with a wire diameter of 0.2 mm was sandblasted and then sprayed with Raney nickel (the mass ratio of nickel to aluminum was 8:2, the purity of nickel was 99.5%, and the purity of aluminum was 99.5%) to form a gram weight of 240 g / m 2 A Raney nickel coating is formed on the nickel mesh to obtain a nickel mesh coated with the Raney nickel coating.

[0052] A nickel mesh coated with Raney nickel coating with a diameter of 54 mm was cut by a 1500W laser, and then the nickel mesh coated with Raney nickel porous coating was immersed and activated in a potassium hydroxide solution with a mass concentration of 30% for 3 hours to obtain a nickel mesh with Raney nickel porous coating.

[0053] Mix a precious metal aqueous solution containing 0.1 mg / mL chloroplatinic acid, hydrochloric acid, and with a pH of 2 - 3 with a nickel mesh having a Raney nickel porous coating, and perform a displacement reaction at 60 °C for 6 h to obtain a hydrogen evolution electrode precursor. Among them, the ratio of the volume of the precious metal aqueous solution to the electrode area is 1.2 mL / cm 2 .

[0054] Perform heat treatment on the hydrogen evolution electrode precursor at 500 °C for 1 h to obtain the hydrogen evolution electrode (the loading amount of platinum element is 0.12 mg / cm 2 ).

[0055] Example 2

[0056] Sandblast a 46 - mesh woven nickel wire mesh with a wire diameter of 0.2 mm and then spray Raney nickel (the mass ratio of nickel to aluminum is 8:2, nickel purity 99.5%, aluminum purity 99.5%) to form a Raney nickel coating with a grammage of 240 g / m 2 to obtain a nickel mesh coated with a Raney nickel coating.

[0057] Use a 1500 - W laser to cut and form a nickel mesh coated with a Raney nickel coating with a diameter of 54 mm. Then, soak and activate the nickel mesh coated with a Raney nickel porous coating with a 30% mass concentration of potassium hydroxide solution for 3 h to obtain a nickel mesh with a Raney nickel porous coating.

[0058] Mix a precious metal aqueous solution containing 0.1 mg / mL chloroplatinic acid, hydrochloric acid, and with a pH of 2 - 3 with a nickel mesh having a Raney nickel porous coating, and perform a displacement reaction at 60 °C for 6 h to obtain a hydrogen evolution electrode precursor. Among them, the ratio of the volume of the precious metal aqueous solution to the electrode area is 2.4 mL / cm 2 .

[0059] Perform heat treatment on the hydrogen evolution electrode precursor at 500 °C for 1 h to obtain the hydrogen evolution electrode (the loading amount of platinum element is 0.24 mg / cm 2 ).

[0060] Example 3

[0061] Sandblast a 46 - mesh woven nickel wire mesh with a wire diameter of 0.2 mm and then spray Raney nickel (the mass ratio of nickel to aluminum is 8:2, nickel purity 99.5%, aluminum purity 99.5%) to form a Raney nickel coating with a grammage of 240 g / m 2 to obtain a nickel mesh coated with a Raney nickel coating.

[0062] A nickel mesh with a diameter of 54 mm coated with a Raney nickel coating is cut and formed by a 1500W laser. Then, the nickel mesh coated with the Raney nickel porous coating is soaked and activated with a potassium hydroxide solution with a mass concentration of 30% for 3 hours to obtain a nickel mesh with a Raney nickel porous coating.

[0063] A noble metal aqueous solution containing 0.5 mg / mL ruthenium chloride, hydrochloric acid, and with a pH of 2 - 3 is mixed with the nickel mesh with a Raney nickel porous coating, and a displacement reaction is carried out at 60 °C for 6 hours to obtain a hydrogen evolution electrode precursor. Among them, the ratio of the volume of the noble metal aqueous solution to the electrode area is 2.4 mL / cm 2 .

[0064] The hydrogen evolution electrode precursor is heat-treated at 500 °C for 1 hour to obtain the hydrogen evolution electrode (the loading amount of ruthenium element is 1.0 mg / cm 2 ).

[0065] The noble metal-based hydrogen evolution electrodes of Examples 1 - 3 are tested. The electrolytic cell structure is assembled as Figure 2 shown (1 - simulated mastoid plate, 2 - cathode, 3 - diaphragm, 4 - anode, 5 - simulated mastoid plate; the front view of the simulated mastoid plate is as Figure 3 shown). The hydrogen evolution electrode is used as the cathode, the anode uses a bare woven nickel wire mesh of the same specification, and the diaphragm uses Agfa UPT500; a potassium hydroxide aqueous solution with a mass concentration of 30% is configured as the electrolyte, and a peristaltic pump is used to transport the electrolyte to the cathode and anode of the electrolytic cell respectively. The flow rate of the electrolyte is 100 mL / min, and the ambient temperature is 25 °C. The input power supply of the electrolytic cell is adjusted to 1.4 - 2.4 V through a constant current and constant voltage power supply, and the polarization curves of the nickel mesh coated with the Raney nickel coating (Raney nickel electrode) of the examples and the hydrogen evolution electrodes of Examples 1 - 3 are monitored by measuring the corresponding output current. The results are as Figure 4 shown.

[0066] It can be seen from Figure 4 that for the four electrodes, as the cell voltage increases, their electrolytic current gradually increases, and as the noble metal loading rate increases, the output current of the electrodes gradually increases. For the electrode mesh loaded with noble metals, its output current in the low polarization region increases with the increase of voltage. When the voltage rises above 2.2 V, the curves coincide, indicating that above this voltage, the electrode current density reaches the limit, and the overall mass transfer performance of the electrolytic cell limits the further improvement of the cell performance.

[0067] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of a hydrogen evolution electrode, characterized in that, The following steps are involved: The nickel mesh coated with the Raney nickel coating is mixed with a strong alkaline solution to undergo an oxidation reaction to remove aluminum in the Raney nickel coating to obtain a nickel mesh with a Raney nickel porous coating; The nickel mesh having the Raney nickel porous coating is mixed with a solution containing a noble metal salt and / or a noble metal complex to carry out a replacement reaction, and the noble metal ions are reduced to metal elements and loaded onto the Raney nickel porous coating to obtain a hydrogen evolution electrode precursor; The hydrogen evolution electrode precursor is subjected to heat treatment to obtain the hydrogen evolution electrode.

2. The preparation method according to claim 1, characterized in that, The mass ratio of nickel to aluminum in the Raney nickel coating is 1:0.2-1.

8.

3. The preparation method according to claim 1, characterized in that, The solution containing the noble metal salt and / or the noble metal complex further comprises an auxiliary agent.

4. The preparation method according to claim 3, characterized in that, The auxiliary agent includes one or more of hydrochloric acid, citric acid and polyvinyl pyrrolidone.

5. The preparation method according to claim 1, characterized in that, The ratio of the volume of the solution containing the precious metal salt and / or the precious metal complex to the area of the nickel mesh with a Raney nickel porous coating is 1 to 3 mL / cm 2 .

6. The preparation method according to claim 1, characterized in that, The noble metal includes one or more of platinum, palladium and ruthenium.

7. The preparation method according to claim 1, characterized in that, The temperature of the replacement reaction is 25-80° C., and the time is 0.5-10 h.

8. The preparation method according to claim 1, characterized in that, The heat treatment temperature is 350-650° C. and the time is 1-5 hours.

9. The hydrogen evolution electrode prepared by the preparation method according to any one of claims 1 to 8, characterized in that, The invention comprises a nickel mesh with a Raney nickel porous coating layer; the Raney nickel porous coating layer is loaded with a noble metal and / or a noble metal oxide.

10. The hydrogen evolution electrode according to claim 9, characterized in that, The loading amount of the noble metal element is 0.05 to 1 mg / cm 2 .

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