Preparation method of copper-gallium alloy electrode and application of copper-gallium alloy electrode in field of electro-catalysis

Abstract

The invention is applicable to the related field of material preparation, and provides a preparation method of a copper-gallium alloy electrode and application of the copper-gallium alloy electrode in the field of electrocatalyst.The preparation method of the copper-gallium alloy electrode comprises the following steps that 1, foamy copper and gallium-indium liquid alloy are immersed in an aqueous solution of sodium hydroxide and make contact with each other; 2, direct current is introduced into a system composed of the foamy copper, the gallium-indium liquid alloy and the sodium hydroxide aqueous solution; step 3, performing ultrasonic treatment on the foamy copper obtained in the step 2; 4, the foamy copper obtained in the step 3 is treated for a certain time under the constant potential; according to the method, foamy copper and gallium-indium liquid alloy are used as raw materials, and a layer of compact copper-gallium alloy is formed on the surface of the foamy copper in an infiltration reaction-physical removal-electrochemical removal mode; the copper-gallium alloy electrode prepared by the method has excellent nitrate electro-catalysis reduction performance, and the ammonia yield reaches 10mg / h.

Description

Technical Field

[0001] The present invention relates to the field related to material preparation, and specifically to a method for preparing a copper-gallium alloy electrode and its application in the field of electrocatalysis. Background Art

[0002] The electrochemical nitrate synthesis of ammonia (NO3RR) reaction is a green way to synthesize ammonia. It can not only treat the nitrate-containing wastewater discharged from the factory harmlessly, but also reduce the consumption of fossil fuels and greenhouse gas emissions in the traditional ammonia synthesis process. It is a technology with great development prospects. The electrochemical nitrate synthesis of ammonia reaction depends on suitable electrocatalysts. 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 the highest electrocatalytic reduction kinetics in NO3RR. Therefore, copper-based catalysts are considered to be the most promising non-precious metal catalysts. However, the current catalysts face the problem of complex synthesis process and are not easy to prepare on a large scale for large-scale production.

[0003] Therefore, in view of the above situation, there is an urgent need for an electrocatalyst with a simple synthesis process and easy large-scale preparation. Since gallium has good wettability on metallic copper, the infiltration method is a convenient way to synthesize materials. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a copper-gallium alloy electrode and its application, aiming to solve the problems in the above-mentioned background technology.

[0005] The present invention is achieved by providing a method for preparing a copper-gallium alloy electrode, the method comprising the following steps:

[0006] Step 1: Immerse the copper foam and the gallium-indium liquid alloy in a sodium hydroxide solution and keep them in contact;

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

[0008] Step 3: subjecting the copper foam obtained in step 2 to ultrasonic treatment;

[0009] Step 4: Treat the copper foam obtained in step 3 at a constant potential for a certain period of time.

[0010] As a further solution of the present invention: in step 1, the length and width of the copper foam are 1.5 cm and 1 cm respectively.

[0011] As a further solution of the present invention: 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, raise the temperature to 300 degrees Celsius within 2 hours under a nitrogen atmosphere, and then keep it warm for 2 hours.

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

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

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

[0015] As a further solution of the present invention: in step 4, 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 -0.8v--1.2v (relative to silver / silver chloride reference electrode), and the cycle time is 0.5-2h.

[0016] A copper-gallium alloy electrode prepared by a copper-gallium alloy electrode preparation method is used in the field of electrocatalysis, characterized in that the copper-gallium alloy electrode is used in the electrocatalytic nitrate synthesis of ammonia, and the ammonia production reaches 10 mg within one hour in a mixed solution of 0.5 mol / L sodium sulfate and 0.1 mol / L sodium nitrate.

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

[0018] The present invention uses foamed copper and 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 foamed copper, a dense layer of copper-gallium alloy compound is formed on the surface of the foamed copper, and all excess liquid metal on the electrode surface is removed by physical and electrochemical methods, exposing the copper-gallium alloy compound with excellent intrinsic performance; the preparation process of the present invention is simple, repeatable, and can be carried out at room temperature, and it is easy to prepare large-area electrodes suitable for industrial production; the copper-gallium alloy electrode prepared by the present invention has excellent NO3RR catalytic performance, and the linear sweep voltammetry test results in different environments show that the current density difference at high potential is close to 100mA / cm 2 , ammonia production reaches 10mg / h. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Digital photos of copper foam (left) and copper foam after gallium infiltration (right).

[0020] Figure 2This is a scanning electron microscope photo of a copper-gallium alloy electrode.

[0021] Figure 3 This is the linear sweep voltammetry curve of the copper-gallium alloy electrode in 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 This is the 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 following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The specific implementation of the present invention is described in detail below in combination with specific embodiments.

[0024] See also Figure 1-Figure 4 , an embodiment of the present invention provides a method for preparing a copper-gallium alloy electrode, the method comprising the following steps:

[0025] Step 1: immerse the copper foam and the gallium-indium liquid alloy in a sodium hydroxide solution and keep them in contact; the length and width of the copper foam 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 it to 300° C. within 2 hours under a nitrogen atmosphere, and then keep it warm for 2 hours; the concentration of the sodium hydroxide solution is 0.05-0.5 mol / L;

[0026] Step 2: Direct current is passed into the system consisting of the copper foam, gallium-indium liquid alloy and sodium hydroxide solution; wherein the copper foam contacts the negative electrode of the power supply, the sodium hydroxide solution contacts the positive electrode of the power supply, and the power supply voltage is 8-16V;

[0027] Step 3: subjecting the copper foam obtained in step 2 to ultrasonic treatment; wherein the ultrasonic power is 600w-1000w, and the ultrasonic time is 0.5-2h;

[0028] Step 4: Treat the copper foam obtained in step 3 at a constant potential for a certain period of 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 -0.8v--1.2v (relative to silver / silver chloride reference electrode), and the cycle time is 0.5-2h.

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

[0030] Embodiment 1

[0031] Step 1: immerse the copper foam and the gallium-indium liquid alloy in a sodium hydroxide solution and keep them in contact; the length and width of the copper foam 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 it to 300° C. within 2 hours under a nitrogen atmosphere, and then keep it warm for 2 hours; the concentration of the sodium hydroxide solution is 0.05-0.5 mol / L;

[0032] Step 2: direct current is passed into the system consisting of the copper foam, gallium-indium liquid alloy and sodium hydroxide solution; wherein the copper foam contacts the negative electrode of the power supply, the sodium hydroxide solution contacts the positive electrode of the power supply, and the power supply voltage is 8V;

[0033] Step 3: subjecting the copper foam obtained in step 2 to ultrasonic treatment; wherein the ultrasonic power is 600w and the ultrasonic time is 2h;

[0034] Step 4: Treat the copper foam obtained in step 3 at a constant potential for a certain period of 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 (relative to the silver / silver chloride reference electrode), and the cycle time is 2 h.

[0035] Embodiment 2

[0036] Step 1: immerse the copper foam and the gallium-indium liquid alloy in a sodium hydroxide solution and keep them in contact; the length and width of the copper foam 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 it to 300° C. within 2 hours under a nitrogen atmosphere, and then keep it warm for 2 hours; the concentration of the sodium hydroxide solution is 0.05-0.5 mol / L;

[0037] Step 2: direct current is passed into the system consisting of the copper foam, gallium-indium liquid alloy and sodium hydroxide solution; wherein the copper foam contacts the negative electrode of the power supply, the sodium hydroxide solution contacts the positive electrode of the power supply, and the power supply voltage is 10V;

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

[0039] Step 4: Treat the copper foam obtained in step 3 at a constant potential for a certain period of 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 -0.9 v (relative to the silver / silver chloride reference electrode), and the cycle time is 1 h.

[0040] Embodiment 3

[0041] Step 1: immerse the copper foam and the gallium-indium liquid alloy in a sodium hydroxide solution and keep them in contact; the length and width of the copper foam are 3 cm and 2 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 it to 300° C. within 2 hours under a nitrogen atmosphere, and then keep it warm for 2 hours; the concentration of the sodium hydroxide solution is 0.05-0.5 mol / L;

[0042] Step 2: Direct current is passed into the system consisting of the copper foam, gallium-indium liquid alloy and sodium hydroxide solution; wherein the copper foam contacts the negative electrode of the power supply, the sodium hydroxide solution contacts the positive electrode of the power supply, and the power supply voltage is 14V;

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

[0044] Step 4: Treat the copper foam obtained in step 3 at a constant potential for a certain period of 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 -1.1 v (relative to the silver / silver chloride reference electrode), and the cycle time is 1.5 h.

[0045] Embodiment 4

[0046] Step 1: immerse the copper foam and the gallium-indium liquid alloy in a sodium hydroxide solution and keep them in contact; the length and width of the copper foam are 3 cm and 2 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 it to 300° C. within 2 hours under a nitrogen atmosphere, and then keep it warm for 2 hours; the concentration of the sodium hydroxide solution is 0.05-0.5 mol / L;

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

[0048] Step 3: subjecting the copper foam obtained in step 2 to ultrasonic treatment; wherein the ultrasonic power is 1000w and the ultrasonic time is 0.5h;

[0049] Step 4: Treat the copper foam obtained in step 3 at a constant potential for a certain period of 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 1.2 V (relative to the silver / silver chloride reference electrode), and the cycle time is 0.5 h.

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

[0051] In summary, the working principle of the present invention is to allow the gallium-indium liquid alloy to infiltrate the surface of the copper foam under electric drive so that the two react to form a copper-gallium alloy, then remove the gallium-indium liquid alloy between the pores of the copper foam by ultrasound, and then completely remove the liquid alloy remaining on the electrode surface by electrochemical means, so that the copper-gallium alloy is completely exposed, thereby preparing a copper-gallium alloy electrode for electrochemical nitrate reduction.

[0052] 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 and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a copper-gallium alloy electrode, characterized in that: The method comprises the following steps: Step 1: Immerse the copper foam and the gallium-indium liquid alloy in a sodium hydroxide solution and keep them in contact; Step 2: Passing direct current into the system consisting of the copper foam, gallium-indium liquid alloy and sodium hydroxide solution; Step 3: subjecting the copper foam obtained in step 2 to ultrasonic treatment; Step 4: Treat the copper foam obtained in step 3 at a constant potential for a certain period of time.

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 1.5 cm and 1 cm 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, raise the temperature to 300°C within 2 hours under a nitrogen atmosphere, and then keep the 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 pole of the power supply, the sodium hydroxide solution contacts the positive pole of the power supply, and 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 method for preparing a copper-gallium alloy electrode according to claim 1, characterized in that: In step 4, the electrolyte is a mixed solution of 0.5 mol / L sodium sulfate and 0.1 mol / L sodium nitrate. Relative to the silver / silver chloride reference electrode, the constant potential treatment potential is -0.8v--1.2v, and the cycle time is 0.5-2h.

8. An application of a copper-gallium alloy electrode prepared by the method for preparing a copper-gallium alloy electrode according to any one of claims 1 to 7 in the field of electrocatalysis, characterized in that: The copper-gallium alloy electrode is used in electrocatalytic nitrate synthesis of ammonia, and the ammonia production in a mixed solution of 0.5 mol / L sodium sulfate and 0.1 mol / L sodium nitrate reaches 10 mg within one hour.

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