Preparation method of copper-gallium alloy electrode and application thereof in electrocatalysis field

Abstract

The application is suitable for the field of material preparation, and provides a copper-gallium alloy electrode preparation method and application in the field of electrocatalysis.The copper-gallium alloy electrode preparation method comprises the following steps: step 1: immersing foamed copper and gallium-indium liquid alloy into an aqueous solution of sodium hydroxide, and keeping the two in contact; step 2: introducing direct current into the system composed of foamed copper, gallium-indium liquid alloy and aqueous solution of sodium hydroxide; step 3: ultrasonicating the foamed copper obtained in step 2; and step 4: treating the foamed copper obtained in step 3 at a constant potential for a certain time.The application forms a dense copper-gallium alloy layer on the surface of foamed copper by means of infiltration reaction-physical removal-electrochemical removal, using foamed copper and gallium-indium liquid alloy as raw materials.The copper-gallium alloy electrode prepared by the application has excellent electrocatalytic nitrate reduction performance, and the ammonia yield reaches 10 mg / h.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of material preparation, and particularly relates to a copper-gallium alloy electrode preparation method and application thereof in the field of electrocatalysis. BACKGROUND

[0002] The electrochemical nitrate reduction to ammonia (NO3RR) reaction is a green way to synthesize ammonia. It can not only harmlessly treat the nitrate-containing wastewater discharged by factories, but also reduce the consumption of fossil fuels and the emission of greenhouse gases in the traditional ammonia synthesis process, and is a technology with great development prospects. The electrochemical nitrate reduction to ammonia reaction depends on a suitable electrocatalyst. Research results show that platinum, copper, iron, ruthenium, nickel, silver and cobalt can be used as cathode materials for NO3RR. Compared with other metals, copper has the fastest speed in the rate-determining step of nitrate conversion to nitrite, and has the highest electrocatalytic reduction kinetics in NO3RR, so copper-based catalysts are considered to be the most potential non-noble metal catalysts. However, the current catalysts have problems such as complex synthesis process and difficulty in large-area preparation for large-scale production.

[0003] Therefore, in view of the above status, there is an urgent need for an electrocatalyst with a simple synthesis process and easy large-area preparation. Since gallium has good wettability to copper, the wetting method is a convenient material synthesis method. SUMMARY

[0004] The present application aims to provide a copper-gallium alloy electrode preparation method and application, and aims to solve the problems in the above background.

[0005] The present application is implemented as follows: a copper-gallium alloy electrode preparation method, which comprises the following steps:

[0006] Step 1: immerse the foamed copper and gallium-indium liquid alloy in a sodium hydroxide solution, and keep the two in contact;

[0007] Step 2: pass direct current into the system composed of foamed copper, gallium-indium liquid alloy and sodium hydroxide solution;

[0008] Step 3: ultrasonic the foamed copper obtained in step 2;

[0009] Step 4: treat the foamed copper obtained in step 3 under constant potential for a certain time.

[0010] As a further scheme of the present application: in step 1, the length and width of the foamed copper are 1.5 cm and 1 cm respectively.

[0011] As a further scheme of the present application: in step 1, the preparation method of the gallium-indium liquid alloy is to place 8.63 g of gallium and 1.37 g of indium in a box-type resistance furnace, heat to 300 DEG C in 2 hours under a nitrogen atmosphere, and then keep the temperature for 2 hours.

[0012] As a further scheme of the present application: in step 1, the concentration of the sodium hydroxide solution is 0.05-0.5 mol / L.

[0013] As a further scheme of the present application: in step 2, the foam copper contacts the negative pole of the power supply, the sodium hydroxide solution contacts the positive pole of the power supply, and the voltage of the power supply is 8-16 v.

[0014] As a further scheme of the present application: in step 3, the ultrasonic power is 600 w-1000 w, and the ultrasonic time is 0.5-2 h.

[0015] As a further scheme of the present application: in step 4, the electrolyte is a mixed solution of 0.5 mol / L sodium sulfate and 0.1 mol / L sodium nitrate, the potentiostatic treatment potential is -0.8 v--1.2 v (relative to a silver / silver chloride reference electrode), and the cycle time is 0.5-2 h.

[0016] The application of a copper-gallium alloy electrode prepared by a copper-gallium alloy electrode preparation method in the field of electrocatalysis is characterized in that the application of the copper-gallium alloy electrode in electrocatalytic synthesis of ammonia from nitrate achieves an ammonia yield of 10 mg in 0.5 mol / L sodium sulfate and 0.1 mol / L sodium nitrate mixed solution within one hour.

[0017] Compared with the prior art, the present application has the following beneficial effects:

[0018] The present application uses foam copper and a gallium-indium liquid alloy as raw materials, and prepares a copper-gallium alloy electrode with a novel structure by means of infiltration reaction-physical removal-electrochemical removal; by virtue of the rapid reaction of gallium and foam copper, a dense copper-gallium alloy compound is formed on the surface of the foam copper, the excess liquid metal on the electrode surface is removed by physical and electrochemical methods, and the copper-gallium alloy compound with excellent intrinsic properties is exposed; the preparation process of the present application is simple, has good repeatability, can be carried out at room temperature, and is easy to prepare large-area electrodes to adapt to industrial production; the copper-gallium alloy electrode prepared by the present application has excellent NO3RR catalytic performance, and the linear sweep voltammetry test results in different environments show that the current density difference at a high potential is close to 100 mA / cm 2 , and the ammonia yield reaches 10 mg / h. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a digital photo of foam copper (left) and foam copper after gallium infiltration (right).

[0020] Figure 2A scanning electron microscope photo of the copper-gallium alloy electrode.

[0021] Figure 3 A linear scan voltammogram of the copper-gallium alloy electrode in a 0.5 mol / L sodium sulfate solution and a mixed solution of 0.5 mol / L sodium sulfate and 0.1 mol / L sodium nitrate.

[0022] Figure 4 A time-current curve of the copper-gallium alloy electrode in a mixed solution of 0.5 mol / L sodium sulfate and 0.1 mol / L sodium nitrate. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application. The specific implementation of the present application will be described in detail below with reference to specific embodiments.

[0024] Please refer to Figures 1-4 The preparation method of the copper-gallium alloy electrode provided in the embodiments of the present application includes the following steps:

[0025] Step 1: immerse the foamed copper and a gallium-indium liquid alloy into a sodium hydroxide solution, and keep the two in contact; wherein the length and width of the foamed copper are 1.5 cm and 1 cm respectively; the preparation method of the gallium-indium liquid alloy is to place 8.63 g of gallium and 1.37 g of indium in a box-type resistance furnace, heat to 300 ℃ within 2 h under a nitrogen atmosphere, and then keep the temperature for 2 h; the concentration of the sodium hydroxide solution is 0.05-0.5 mol / L;

[0026] Step 2: pass direct current into the system composed of the foamed copper, the gallium-indium liquid alloy and the sodium hydroxide solution; wherein the foamed copper is connected to the negative pole of the power supply, the sodium hydroxide solution is connected to the positive pole of the power supply, and the voltage of the power supply is 8-16 V;

[0027] Step 3: ultrasonic the foamed copper obtained in step 2; wherein the ultrasonic power is 600-1000 W, and the ultrasonic time is 0.5-2 h;

[0028] Step 4: treat the foamed copper obtained in step 3 under constant potential for a certain time; wherein the electrolyte is a mixed solution of 0.5 mol / L sodium sulfate and 0.1 mol / L sodium nitrate, the constant potential treatment potential is -0.8 V to -1.2 V (relative to a silver / silver chloride reference electrode), and the cycle time is 0.5-2 h.

[0029] In the embodiment, the copper-gallium alloy electrode with novel structure is prepared by the method of infiltration reaction-physical removal-electrochemical removal, using foamed copper and gallium-indium liquid alloy as raw materials; a dense copper-gallium alloy compound is formed on the surface of the foamed copper by the rapid reaction of gallium and foamed copper; the excess liquid metal on the electrode surface is removed by physical and electrochemical methods, and the copper-gallium alloy compound with excellent intrinsic performance is exposed; the preparation process of the application is simple, has good repeatability, can be carried out at room temperature, and is easy to prepare large-area electrodes to adapt to industrial production; the copper-gallium alloy electrode prepared by the application has excellent NO3RR catalytic performance; the linear sweep voltammetry test results in different environments show that the current density difference at high potential is close to 100mA / cm 2 , and the ammonia production reaches 10mg / h.

[0030] Example one

[0031] Step 1: immerse the foamed copper and gallium-indium liquid alloy in a sodium hydroxide solution and keep them in contact; wherein the length and width of the foamed copper are 1.5cm and 1cm respectively; the preparation method of the gallium-indium liquid alloy is to place 8.63g of gallium and 1.37g of indium in a box-type resistance furnace, heat to 300℃ under nitrogen atmosphere within 2h, and then keep the temperature for 2h; the concentration of the sodium hydroxide solution is 0.05-0.5mol / L;

[0032] Step 2: pass direct current into the system composed of foamed copper, gallium-indium liquid alloy and sodium hydroxide solution; wherein the foamed copper contacts the negative pole of the power supply, and the sodium hydroxide solution contacts the positive pole of the power supply, and the voltage of the power supply is 8v;

[0033] Step 3: ultrasonic the foamed copper obtained in step 2; wherein the ultrasonic power is 600w, and the ultrasonic time is 2h;

[0034] Step 4: treat the foamed copper obtained in step 3 at a constant potential for a certain time; wherein the electrolyte is a mixed solution of 0.5mol / L sodium sulfate and 0.1mol / L sodium nitrate, the constant potential treatment potential is-0.8v (relative to the silver / silver chloride reference electrode), and the cycle time is 2h.

[0035] Example two

[0036] Step 1: immerse the foamed copper and gallium-indium liquid alloy in a sodium hydroxide solution and keep them in contact; wherein the length and width of the foamed copper are 1.5cm and 1cm respectively; the preparation method of the gallium-indium liquid alloy is to place 8.63g of gallium and 1.37g of indium in a box-type resistance furnace, heat to 300℃ under nitrogen atmosphere within 2h, and then keep the temperature for 2h; the concentration of the sodium hydroxide solution is 0.05-0.5mol / L;

[0037] Step 2: Direct current is introduced into the system composed of foamed copper, gallium-indium liquid alloy and sodium hydroxide solution; wherein the foamed copper contacts the negative pole of the power supply, the sodium hydroxide solution contacts the positive pole of the power supply, and the voltage of the power supply is 10v;

[0038] Step 3: The foamed copper obtained in step 2 is subjected to ultrasonic treatment; wherein the ultrasonic power is 750w, and the ultrasonic time is 1.5h;

[0039] Step 4: The foamed copper obtained in step 3 is treated at a constant potential for a certain period of time; wherein the electrolyte is a mixed solution of 0.5mol / L sodium sulfate and 0.1mol / L sodium nitrate, the constant potential treatment potential is-0.9v (relative to the silver / silver chloride reference electrode), and the cycle time is 1h.

[0040] Example Three

[0041] Step 1: Foamed copper and gallium-indium liquid alloy are immersed in a sodium hydroxide solution and kept in contact; wherein the length and width of the foamed copper are 3cm and 2cm respectively; the preparation method of the gallium-indium liquid alloy is to place 8.63g of gallium and 1.37g of indium in a box-type resistance furnace, heat to 300℃ under a nitrogen atmosphere within 2h, and then keep the temperature for 2h; the concentration of the sodium hydroxide solution is 0.05-0.5mol / L;

[0042] Step 2: Direct current is introduced into the system composed of foamed copper, gallium-indium liquid alloy and sodium hydroxide solution; wherein the foamed copper contacts the negative pole of the power supply, the sodium hydroxide solution contacts the positive pole of the power supply, and the voltage of the power supply is 14v;

[0043] Step 3: The foamed copper obtained in step 2 is subjected to ultrasonic treatment; wherein the ultrasonic power is 850w, and the ultrasonic time is 1h;

[0044] Step 4: The foamed copper obtained in step 3 is treated at a constant potential for a certain period of time; wherein the electrolyte is a mixed solution of 0.5mol / L sodium sulfate and 0.1mol / L sodium nitrate, the constant potential treatment potential is-1.1v (relative to the silver / silver chloride reference electrode), and the cycle time is 1.5h.

[0045] Example Four

[0046] Step 1: Foamed copper and gallium-indium liquid alloy are immersed in a sodium hydroxide solution and kept in contact; wherein the length and width of the foamed copper are 3cm and 2cm respectively; the preparation method of the gallium-indium liquid alloy is to place 8.63g of gallium and 1.37g of indium in a box-type resistance furnace, heat to 300℃ under a nitrogen atmosphere within 2h, and then keep the temperature for 2h; the concentration of the sodium hydroxide solution is 0.05-0.5mol / L;

[0047] Step 2: direct current is introduced into the system composed of foamed copper, gallium-indium liquid alloy and sodium hydroxide solution; wherein the foamed copper contacts the negative pole of the power supply, the sodium hydroxide solution contacts the positive pole of the power supply, and the voltage of the power supply is 16V;

[0048] Step 3: the foamed copper obtained in step 2 is subjected to ultrasonic treatment; wherein the ultrasonic power is 1000W, and the ultrasonic time is 0.5h;

[0049] Step 4: the foamed copper obtained in step 3 is treated at a constant potential for a certain time; wherein the electrolyte is a mixed solution of 0.5mol / L sodium sulfate and 0.1mol / L sodium nitrate, the constant potential treatment potential is 1.2V (relative to the silver / silver chloride reference electrode), and the cycle time is 0.5h.

[0050] The application of the copper-gallium alloy electrode prepared according to the above-mentioned copper-gallium alloy electrode preparation method in the field of electrocatalysis is characterized in that the application of the copper-gallium alloy electrode in electrocatalytic synthesis of ammonia from nitrate is that the ammonia yield reaches 10mg in 0.5mol / L sodium sulfate and 0.1mol / L sodium nitrate mixed solution within one hour.

[0051] In summary, the working principle of the present application is that under the electric drive, the gallium-indium liquid alloy is infiltrated on the surface of the foamed copper to react with the foamed copper to form a copper-gallium alloy, then the gallium-indium liquid alloy between the pores of the foamed copper is removed by ultrasonic method, and then the residual liquid alloy on the surface of the electrode is completely removed by electrochemical method, so that the copper-gallium alloy is completely exposed, and then a copper-gallium alloy electrode for electrochemical reduction of nitrate is prepared.

[0052] The above only describes the preferred embodiments of the present application and should not be used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing a copper-gallium alloy electrode, characterized in that, The method includes the following steps: Step 1: Immerse the foamed copper and the gallium-indium liquid alloy in a sodium hydroxide solution and keep them in contact; Step 2: Apply direct current to the system consisting of copper foam, gallium indium liquid alloy, and sodium hydroxide solution; Step 3: Sonicate the copper foam obtained in Step 2; Step 4: Treat the copper foam obtained in Step 3 under constant potential for a certain period of time; the electrolyte is a mixed solution of 0.5 mol / L sodium sulfate and 0.1 mol / L sodium nitrate, and the constant potential treatment potential relative to the silver / silver chloride reference electrode is -0.8 V to -1.2 V, and the cycle time is 0.5-2 h.

2. The method for preparing a copper-gallium alloy electrode according to claim 1, characterized in that, The length and width of the copper foam are 1.5cm and 1cm respectively.

3. The method for preparing a copper-gallium alloy electrode according to claim 1, characterized in that, In step 1, the preparation method of gallium-indium liquid alloy is to place 8.63g of gallium and 1.37g of indium in a box-type resistance furnace, heat it to 300°C within 2 hours under a nitrogen atmosphere, and then hold it at that temperature for 2 hours.

4. The method for preparing a copper-gallium alloy electrode according to claim 1, characterized in that, In step 1, the concentration of the sodium hydroxide solution is 0.05-0.5 mol / L.

5. The method for preparing a copper-gallium alloy electrode according to claim 1, characterized in that, In step 2, the copper foam contacts the negative terminal of the power supply, and the sodium hydroxide solution contacts the positive terminal of the power supply. The power supply voltage is 8-16V.

6. The method for preparing a copper-gallium alloy electrode according to claim 1, characterized in that, In step 3, the ultrasonic power is 600w-1000w and the ultrasonic time is 0.5-2h.

7. The application of a copper-gallium alloy electrode prepared by the method according to any one of claims 1-6 in the field of electrocatalysis, characterized in that, The copper-gallium alloy electrode was used in the electrocatalytic synthesis of ammonia from nitrates, achieving an ammonia yield of 10 mg per hour in a mixed solution of 0.5 mol / L sodium sulfate and 0.1 mol / L sodium nitrate.

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