Electrode material and preparation method and application thereof

Abstract

The invention provides an electrode material and a preparation method and application thereof, and belongs to the technical field of water treatment and purification. The preparation method of the electrode material comprises the following steps: (1) dipping foamed nickel in a copper salt solution, adding ammonia water, and carrying out deposition oxidation treatment to obtain foamed nickel loaded with copper oxide microspheres; and (2) carrying out heat treatment on the foamed nickel loaded with the copper oxide microspheres obtained in the step (1) to obtain the electrode material of the foamed nickel loaded with the copper / copper oxide microspheres. The foamed nickel in the prepared electrode material has a porous structure and a large specific surface area, the uniformity of copper / copper oxide can be improved, more active sites can be exposed, the copper / copper oxide microspheres serve as active substances, 0-valence copper and + 2-valence copper interact with each other, nitrate can obtain electrons to be reduced, the removal rate of nitrate is increased, and the electrode material has a good application prospect. And meanwhile, the electrode material has relatively good stability.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment and purification, and in particular to an electrode material, a preparation method thereof, and an application thereof. Background Art

[0002] Nitrate is the primary form of nitrogen in water. Excessive nitrate levels can have detrimental effects on human health and ecological safety, leading to eutrophication and hypoxia in surface waters. It is also linked to methemoglobinemia, gastric cancer, and other diseases. Traditional nitrate treatment methods include physical enrichment, biological denitrification, and chemical reduction.

[0003] During the electrocatalytic reduction of nitrate in water, nitrate is reduced to NO2 at the cathode active site. - -N, NH4 + -N or N2, NO2 contained in water - -N seriously threatens human health, NH4 + Excessive -N content can lead to eutrophication of water bodies. Among these nitrate reduction products, N2 is the preferred product because it is harmless to the human body. Metal foam materials such as nickel foam have been proven to be ideal water treatment electrode materials because of their porous structure and large surface area. On the other hand, copper-based catalysts have the advantages of inhibiting hydrogen evolution reaction and reducing NO3 - The good binding ability of Cu makes it a promising candidate for nitrate reduction reaction. In addition, the energy level of Cu d orbital is close to that of LUMOπ* molecular orbital of nitrate, which helps copper-based catalysts promote nitrate reduction. 0.8 Cu 0.2 @CuO, 3D copper nanobelts, and Cu-NFs have all been applied to electrocatalytic nitrate removal. Despite these advances, existing copper-based catalysts still exhibit low nitrate removal rates and poor stability. Therefore, improving the nitrate removal efficiency and stability of these catalysts remains a challenge in existing technologies. Summary of the Invention

[0004] The object of the present invention is to provide an electrode material and its preparation method and application. The electrode material prepared by the present invention has an excellent removal rate of nitrate in water and has good stability.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing an electrode material, comprising the following steps:

[0007] (1) immersing nickel foam in a copper salt solution, adding ammonia water, and performing a deposition oxidation treatment to obtain nickel foam loaded with copper oxide microspheres;

[0008] (2) heat-treating the nickel foam loaded with copper oxide microspheres obtained in step (1) to obtain an electrode material of nickel foam loaded with copper / copper oxide microspheres; the heat treatment is performed in a nitrogen atmosphere.

[0009] Preferably, the copper salt solution in step (1) comprises an aqueous solution of copper nitrate, an aqueous solution of copper chloride or an aqueous solution of copper sulfate.

[0010] Preferably, the concentration of the copper salt solution in step (1) is 0.05 to 0.15 mol / L.

[0011] Preferably, the pH value of the solution after adding ammonia water in step (1) is 11-13.

[0012] Preferably, the temperature of the deposition oxidation treatment in step (1) is 75 to 85° C., and the time of the deposition oxidation treatment is 6 to 8 hours.

[0013] Preferably, the temperature of the heat treatment in step (2) is 540-560° C., and the time of the heat treatment is 1-3 hours.

[0014] Preferably, the heating rate of heating to the heat treatment temperature in step (2) is 4-6°C / min.

[0015] The present invention also provides an electrode material prepared by the preparation method described in the above technical solution.

[0016] The present invention also provides the use of the electrode material described in the above technical solution in electrocatalytic removal of nitrates in water.

[0017] The present invention provides a method for preparing an electrode material, comprising the following steps: (1) immersing nickel foam in a copper salt solution, adding ammonia water, and performing a deposition oxidation treatment to obtain nickel foam loaded with copper oxide microspheres; (2) heat-treating the nickel foam loaded with copper oxide microspheres obtained in step (1) to obtain an electrode material of nickel foam loaded with copper / copper oxide microspheres; the heat treatment is performed in a nitrogen atmosphere. The nickel foam in the electrode material prepared by the present invention has a porous structure and a large specific surface area, which can improve the uniformity of copper / copper oxide and expose more active sites. The copper / copper oxide microspheres act as active substances, and the interaction between the 0-valent state and the +2-valent state of copper is conducive to the reduction of nitrates by electrons, thereby improving the removal rate of nitrates. At the same time, the electrode material has good stability. The results of the embodiment show that when the electrode material prepared by the present invention is used for electrocatalytic removal of nitrates in water, the removal rate of nitrate nitrogen can reach 100%, and the removal rate is still excellent after 5 cycles, and the electrode material has good stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1This is a schematic diagram of the process for preparing electrode materials according to Example 1 of the present invention;

[0019] Figure 2 This is a SEM image of the CuOms-NF prepared in step (2) of Example 1 of the present invention;

[0020] Figure 3 This is the SEM image of the Cu / CuOms-NF prepared in step (3) of Example 1 of the present invention;

[0021] Figure 4 TEM image of Cu / CuOms-NF prepared in step (3) of Example 1 of the present invention;

[0022] Figure 5 High-resolution transmission image and element distribution map of Cu / CuOms-NF prepared in Example 1 of the present invention;

[0023] Figure 6 The XRD pattern of CuOms-NF prepared in step (2) of Example 1 of the present invention;

[0024] Figure 7 This is the XRD pattern of Cu / CuOms-NF prepared in step (3) of Example 1 of the present invention;

[0025] Figure 8 The X-ray photoelectron spectroscopy (XPS) graph of Cu 2p of the Cu / CuOms-NF prepared in step (3) of Example 1 of the present invention;

[0026] Figure 9 This is the X-ray photoelectron spectroscopy (XPS) graph of O1s of the Cu / CuOms-NF prepared in step (3) of Example 1 of the present invention;

[0027] Figure 10 The removal rate of nitrate nitrogen in water in Application Example 1 of the present invention and Comparative Application Examples 1-2;

[0028] Figure 11 The yield of nitrite nitrogen in the electrocatalytic process of Application Example 1 of the present invention and Comparative Application Examples 1-2;

[0029] Figure 12 The yield of ammonia nitrogen in the electrocatalytic process of Application Example 1 of the present invention and Comparative Application Examples 1-2;

[0030] Figure 13 The ratios of nitrate nitrogen, nitrite nitrogen, ammonia nitrogen and nitrogen gas in the electrocatalytic process of Application Example 1 of the present invention and Comparative Application Examples 1 and 2;

[0031] Figure 14 is the removal rate of nitrate nitrogen in Application Examples 1 to 4 of the present invention;

[0032] Figure 15 is the yield of nitrite nitrogen in the electrocatalytic process of Application Examples 1 to 4 of the present invention;

[0033] Figure 16 The yield of ammonia nitrogen in the electrocatalytic process of Application Examples 1 to 4 of the present invention;

[0034] Figure 17 The ratios of nitrate nitrogen, nitrite nitrogen, ammonia nitrogen and nitrogen and the nitrogen selectivity in the electrocatalytic processes of Application Examples 1 to 4 of the present invention;

[0035] Figure 18 is the removal rate of nitrate nitrogen in Application Example 1 and Application Examples 5 to 7 of the present invention;

[0036] Figure 19 The yield of nitrite nitrogen in the electrocatalytic process of Application Examples 1 and Application Examples 5 to 7 of the present invention;

[0037] Figure 20 The yield of ammonia nitrogen in the electrocatalytic process of Application Examples 1 and Application Examples 5 to 7 of the present invention;

[0038] Figure 21 The ratios of nitrate nitrogen, nitrite nitrogen, ammonia nitrogen and nitrogen and the nitrogen selectivity in the electrocatalytic process of Application Examples 1 and Application Examples 5 to 7 of the present invention;

[0039] Figure 22 is the removal rate of nitrate nitrogen in Application Examples 1 and Application Examples 8-9 of the present invention;

[0040] Figure 23 The yield of nitrite nitrogen in the electrocatalytic process of Application Examples 1 and Application Examples 8-9 of the present invention;

[0041] Figure 24 The yield of ammonia nitrogen in the electrocatalytic process of Application Examples 1 and Application Examples 8-9 of the present invention;

[0042] Figure 25 The ratios of nitrate nitrogen, nitrite nitrogen, ammonia nitrogen and nitrogen and the nitrogen selectivity in the electrocatalytic processes of Application Examples 1 and Application Examples 8-9 of the present invention;

[0043] Figure 26 It is the removal rate of nitrate nitrogen and nitrogen selectivity in Application Example 10 of the present invention. DETAILED DESCRIPTION

[0044] The present invention provides a method for preparing an electrode material, comprising the following steps:

[0045] (1) immersing nickel foam in a copper salt solution, adding ammonia water, and performing a deposition oxidation treatment to obtain nickel foam loaded with copper oxide microspheres;

[0046] (2) heat-treating the nickel foam loaded with copper oxide microspheres obtained in step (1) to obtain an electrode material of nickel foam loaded with copper / copper oxide microspheres.

[0047] Unless otherwise specified, the present invention has no particular limitation on the sources of the raw materials, and commercially available products known to those skilled in the art may be used.

[0048] The invention immerses the nickel foam in a copper salt solution, adds ammonia water, and performs deposition oxidation treatment to obtain the nickel foam loaded with copper oxide microspheres.

[0049] In the present invention, the nickel foam is preferably pretreated before use; this pretreatment preferably involves ultrasonic cleaning in 1 mol / L hydrochloric acid, ethanol, and deionized water for 5 to 20 minutes, sequentially. The amounts of hydrochloric acid, ethanol, and deionized water used, or the ultrasonic power, are not particularly limited, and techniques familiar to those skilled in the art can be employed. In the present invention, this pretreatment removes the oxide layer on the surface of the nickel foam, ensuring a clean surface.

[0050] In the present invention, the size of the nickel foam is preferably (1-3) cm*(2-4) cm*1 cm, more preferably 2 cm*3 cm*1 cm. When the size of the nickel foam does not meet the requirements, the present invention preferably cuts the nickel foam. The present invention does not specifically limit the cutting operation, and a cutting method well known to those skilled in the art can be used to ensure that the size of the nickel foam meets the requirements.

[0051] In the present invention, the amount of the nickel foam is preferably 2 pieces, i.e., 2 pieces of nickel foam with a size of (1-3) cm*(2-4) cm*1 cm. The present invention limits the size and amount of the nickel foam to the above range so that the surface of the nickel foam can be fully loaded with the synthesized copper oxide microspheres.

[0052] In the present invention, the copper salt solution preferably includes an aqueous solution of copper nitrate, an aqueous solution of copper chloride or an aqueous solution of copper sulfate; the concentration of the copper salt solution is preferably 0.05 to 0.15 mol / L, more preferably 0.1 mol / L. When two pieces of nickel foam with a size of (1 to 3) cm*(2 to 4) cm*1 cm are used, the amount of the copper salt solution is preferably 70 to 90 mL, more preferably 80 mL. The present invention limits the concentration and amount of the copper salt solution to the above range, which can ensure that the nickel foam is completely immersed in the solution and can ensure that the reaction is fully carried out. Too much copper salt concentration will cause the product structure to be destroyed, and too low a concentration will not form a deposit on the surface of the nickel foam.

[0053] In the present invention, the pH value of the solution after adding the ammonia water is preferably 11 to 13, more preferably 12. The present invention does not specifically limit the concentration and amount of the ammonia water, as long as the pH value of the solution after addition is within the above range. Limiting the pH value of the solution within the above range facilitates the reaction of the copper salt to form copper oxide microspheres.

[0054] In the present invention, the deposition oxidation treatment temperature is preferably 75-85°C, more preferably 80°C; the deposition oxidation treatment duration is preferably 6-8 hours, more preferably 6-7 hours; and the deposition oxidation treatment is preferably performed under static conditions. During the deposition oxidation treatment, the copper salt forms copper oxide microspheres that are loaded onto the surface of the nickel foam. Limiting the deposition oxidation treatment temperature and duration within the aforementioned ranges allows the reaction to proceed fully.

[0055] After the deposition oxidation treatment is completed, the present invention preferably washes the product after the deposition oxidation treatment with water to obtain nickel foam loaded with copper oxide microspheres.

[0056] The present invention has no special limitation on the water washing operation, and the water washing technical solutions well known to those skilled in the art can be used.

[0057] After obtaining the nickel foam loaded with copper oxide microspheres, the present invention heat-treats the nickel foam loaded with copper oxide microspheres to obtain an electrode material of nickel foam loaded with copper / copper oxide microspheres.

[0058] In the present invention, the heat treatment temperature is preferably 540-560°C, more preferably 550°C; the heat treatment duration is preferably 1-3 hours, more preferably 2 hours; the heating rate to the heat treatment temperature is preferably 4-6°C / min, more preferably 5°C / min; and the heat treatment is performed in a nitrogen atmosphere. During the heat treatment at high temperature and in the absence of air, nickel mediates the formation of elemental copper by causing some of the +2-valent copper to gain electrons. Limiting the heat treatment parameters within the aforementioned ranges is more conducive to obtaining copper / copper oxide microspheres.

[0059] After the heat treatment is completed, the present invention preferably cools the heat-treated product to obtain an electrode material of nickel foam loaded copper / copper oxide microspheres.

[0060] The present invention has no special limitation on the cooling operation, and any cooling technical solution well known to those skilled in the art may be used.

[0061] The nickel foam in the electrode material prepared by the present invention has a porous structure and a large specific surface area, which can improve the uniformity of copper / copper oxide and expose more active sites. The copper / copper oxide microspheres serve as active substances, and the interaction between the 0-valent state and the +2-valent state of copper is conducive to the electron reduction of nitrates. The process parameters are controlled to improve the nitrate removal rate. At the same time, the electrode material has good stability.

[0062] The present invention also provides an electrode material prepared by the preparation method described in the above technical solution.

[0063] The electrode material prepared by the present invention has excellent removal rate of nitrate in water and good stability.

[0064] The present invention also provides the use of the electrode material described in the above technical solution in electrocatalytic removal of nitrates in water.

[0065] In the present invention, when electrocatalytically removing nitrate from water, the cathode is the electrode material described in the above technical solution, the reference electrode is preferably Ag / AgCl, the anode is preferably platinum wire, the electrode spacing is preferably 1.5-2 cm, and the applied potential is preferably -1.3 V vs. Ag / AgCl.

[0066] In the present invention, the concentration of nitrate nitrogen in the water is preferably 1 to 200 mg / L; the concentration of sodium sulfate is preferably 0.1 mol / L; the concentration of chloride ions is preferably 0 to 0.15 mol / L; and the pH value of the aqueous solution is preferably 3 to 11. Using these parameters can improve the nitrate removal rate and stability of the electrode material.

[0067] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0068] Example 1

[0069] Example 1 Schematic diagram of the process for preparing electrode materials Figure 1 As shown:

[0070] (1) Nickel foam (NF) was cut into 2 cm * 3 cm * 1 cm sheets and ultrasonically cleaned in 1 mol / L hydrochloric acid, ethanol, and deionized water for 10 min in sequence;

[0071] (2) Two cleaned nickel foams were placed in 80 mL of 0.1 mol / L copper nitrate aqueous solution, and ammonia was added to adjust the pH value of the solution to 12. The solution was then subjected to deposition oxidation treatment at 80°C for 6 h and then washed with water to obtain nickel foam loaded with copper oxide microspheres, which was designated as CuOms-NF.

[0072] (3) The nickel foam loaded with copper oxide microspheres obtained in step (2) was placed in the middle position of a tube furnace, kept warm at 550°C in a nitrogen atmosphere for 2 h at a heating rate of 5°C / min, and cooled to obtain an electrode material of nickel foam loaded with copper / copper oxide microspheres, which was recorded as Cu / CuOms-NF.

[0073] The CuOms-NF prepared in step (2) of Example 1 was observed using a scanning electron microscope, and the SEM images obtained at different magnifications were as follows: Figure 2 As shown, the Cu / CuOms-NF prepared in step (3) of Example 1 was observed using a scanning electron microscope, and the SEM images obtained at different magnifications were as follows: Figure 3 As shown. Figures 2-3 It can be seen that the CuO microspheres and Cu / CuO microspheres have spherical structures.

[0074] The Cu / CuOms-NF prepared in step (3) of Example 1 was observed using a transmission electron microscope, and the obtained TEM image is as follows: Figure 4 As shown. Figure 4 It can be seen that the lattice spacing of Cu(111) is 0.21nm and the lattice spacing of CuO(111) is 0.23nm.

[0075] The high-resolution transmission image and element distribution map of Cu / CuOms-NF prepared in step (3) of Example 1 are shown in FIG. Figure 5 As shown, from left to right are the high-resolution transmission image of Cu / CuOms-NF, the Cu element distribution map and the O element distribution map. Figure 5 It can be seen that copper and oxygen elements are evenly distributed on the surface of the electrode material.

[0076] The XRD pattern of CuOms-NF prepared in step (2) of Example 1 is as follows: Figure 6 As shown; the XRD pattern of Cu / CuOms-NF prepared in step (3) of Example 1 is as shown Figure 7 The X-ray photoelectron spectroscopy (XPS) of Cu 2p and O1s of the Cu / CuOms-NF prepared in step (3) of Example 1 are shown as follows: Figure 8 and Figure 9 As shown. Figures 6-9 It can be seen that there is copper and copper oxide.

[0077] Application Example 1

[0078] The Cu / CuOms-NF electrode material prepared in Example 1 was cut into a size of 1.5 cm*1.5 cm*1 cm as the cathode, Ag / AgCl as the reference electrode, platinum wire as the anode, the electrode spacing was 1.5 cm, the applied potential was -1.3 V vs. Ag / AgCl, and nitrate in water was electrocatalyzed. The concentration of nitrate nitrogen in the water was 50 mg / L, the chloride ion concentration was 0.1 mol / L, the sodium sulfate concentration was 0.1 mol / L, and the pH value was 6.2.

[0079] Comparative Application Example 1

[0080] The cathode in Application Example 1 was replaced with the nickel foam NF cleaned in step (1) of Example 1, and the other parameters were the same as those in Application Example 1.

[0081] Comparative Application Example 2

[0082] The cathode in Application Example 1 was replaced with the CuOms-NF prepared in step (2) of Example 1, and the other parameters were the same as those in Application Example 1.

[0083] Application Example 1, Comparative Application Examples 1-2: The removal rate of nitrate nitrogen in water is as follows: Figure 10 As shown. Figure 10 It can be seen that the removal rates of nitrate nitrogen in water by NF, CuOms-NF and Cu / CuOms-NF are 6.20%, 96.49% and 99.72%, respectively.

[0084] Application Example 1, Comparative Application Examples 1-2 The yield of nitrite nitrogen in the electrocatalytic process is as follows Figure 11 As shown, the yield of ammonia nitrogen is Figure 12 As shown in the figure, the ratios of nitrate nitrogen, nitrite nitrogen, ammonia nitrogen and nitrogen gas in the electrocatalytic process are as follows: Figure 13 As shown. Figures 11-13 It can be seen that NF acts as a cathode to electrocatalyze the removal of NO3 - -N has low efficiency, so basically no by-products are produced. CuOms-NF will produce more toxic by-products (such as NO2 - -N、NH4 + -N), and using Cu / CuOms / NF as the cathode material can solve this problem. During the electrocatalytic reaction, no large amount of by-products are formed, and the selectivity of N2 can reach 97.97%.

[0085] Application Example 2

[0086] The pH value of the aqueous solution in Application Example 1 was replaced with 3, and the other parameters were the same as those in Application Example 1.

[0087] Application Example 3

[0088] The pH value of the aqueous solution in Application Example 1 was replaced with 9, and the other parameters were the same as those in Application Example 1.

[0089] Application Example 4

[0090] The pH value of the aqueous solution in Application Example 1 was replaced with 11, and the other parameters were the same as those in Application Example 1.

[0091] The removal rates of nitrate nitrogen in application examples 1 to 4 are as follows: Figure 14 As shown. Figure 14 It can be seen that when the pH values ​​are 3, 6.2, 9 and 11, the removal rates of nitrate nitrogen are 100%, 99.72%, 99.81% and 99.94% respectively.

[0092] The yield of nitrite nitrogen in the electrocatalytic process of Application Examples 1 to 4 is as follows: Figure 15 As shown, the yield of ammonia nitrogen is Figure 16 As shown in the figure, the ratio of nitrate nitrogen, nitrite nitrogen, ammonia nitrogen and nitrogen and the nitrogen selectivity in the electrocatalytic process are as follows: Figure 17 As shown. Figures 15-16 It can be seen that in the electrolyte solutions with different acidity and alkalinity, NO2 - -N content showed a trend of increasing first and then decreasing, accompanied by trace amounts of NH4 + -N generates. Figure 17 It can be seen that when the pH values ​​are 3, 6.2, 9 and 11, the selectivity of nitrogen is 100%, 97.97%, 97.88% and 97.67%, respectively.

[0093] Application Example 5

[0094] The concentration of chloride ions in water in Application Example 1 was replaced with 0.00 mol / L, and the other parameters were the same as those in Application Example 1.

[0095] Application Example 6

[0096] The concentration of chloride ions in water in Application Example 1 was replaced with 0.05 mol / L, and the other parameters were the same as those in Application Example 1.

[0097] Application Example 7

[0098] The concentration of chloride ions in water in Application Example 1 was replaced with 0.15 mol / L, and the other parameters were the same as those in Application Example 1.

[0099] The removal rates of nitrate nitrogen in Application Examples 1 and 5-7 are as follows: Figure 18 As shown. Figure 18It can be seen that when the chloride ion concentration is 0.00, 0.05, 0.10 and 0.15 mol / L, the removal rates of nitrate nitrogen are 100%, 100%, 99.72% and 100% respectively.

[0100] The yield of nitrite nitrogen in the electrocatalytic process of Application Examples 1 and 5-7 is as follows: Figure 19 As shown, the yield of ammonia nitrogen is Figure 20 As shown in the figure, the ratio of nitrate nitrogen, nitrite nitrogen, ammonia nitrogen and nitrogen and the nitrogen selectivity in the electrocatalytic process are as follows: Figure 21 As shown. Figures 19-20 It can be seen that the by-product NO2 in the electrocatalytic process - -N content showed a trend of increasing first and then decreasing, NH4 + The concentration of -N decreases with the increase of chloride ion concentration. Figure 21 It can be seen that when the chloride ion concentration is 0.00, 0.05, 0.10 and 0.15 mol / L, the nitrogen selectivity is 16.60%, 69.96%, 97.97% and 100%, respectively.

[0101] Application Example 8

[0102] The concentration of nitrate nitrogen in water in Application Example 1 was replaced with 100 mg / L, and the other parameters were the same as those in Application Example 1.

[0103] Application Example 9

[0104] The concentration of nitrate nitrogen in water in Application Example 1 was replaced with 200 mg / L, and the other parameters were the same as those in Application Example 1.

[0105] The removal rates of nitrate nitrogen in Application Examples 1 and 8-9 are as follows: Figure 22 As shown. Figure 22 It can be seen that when the nitrate nitrogen concentration is 50, 100 and 200 mg / L, the nitrate nitrogen removal rates are 99.72%, 83.33% and 64.21%, respectively.

[0106] The yield of nitrite nitrogen in the electrocatalytic process of Application Examples 1 and 8-9 is as follows: Figure 23 As shown, the yield of ammonia nitrogen is Figure 24 As shown in the figure, the ratio of nitrate nitrogen, nitrite nitrogen, ammonia nitrogen and nitrogen and the nitrogen selectivity in the electrocatalytic process are as follows: Figure 25 As shown. Figures 23-24 It can be seen that as the concentration of nitrate nitrogen in the electrolyte increases, the content of nitrite nitrogen also increases, and the content of by-product ammonia nitrogen also increases slightly. Figure 25It can be seen that when the nitrate nitrogen concentration is 50, 100 and 200 mg / L, the nitrogen selectivity is 97.97%, 67.27% and 15.59%, respectively.

[0107] Application Example 10

[0108] The Cu / CuOms-NF prepared in Example 1 was tested 5 times in a cycle according to the method of Application Example 1. The removal rate of nitrate nitrogen and nitrogen selectivity were as follows: Figure 26 As shown. Figure 26 It can be seen that the nitrate nitrogen removal rate and nitrogen selectivity of the same electrode material remain almost unchanged after 5 cycles, indicating that the electrode material prepared by the present invention has excellent stability.

[0109] In summary, the electrode material prepared by the present invention has an excellent removal rate for nitrate nitrogen in water and has excellent stability.

[0110] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing an electrode material, comprising the following steps: (1) immersing nickel foam in a copper salt solution, adding ammonia water, and performing a deposition oxidation treatment to obtain nickel foam loaded with copper oxide microspheres; (2) heat-treating the nickel foam loaded with copper oxide microspheres obtained in step (1) to obtain an electrode material of nickel foam loaded with copper / copper oxide microspheres; the heat treatment is performed in a nitrogen atmosphere.

2. The preparation method according to claim 1, characterized in that The copper salt solution in step (1) includes a copper nitrate aqueous solution, a copper chloride aqueous solution or a copper sulfate aqueous solution.

3. The preparation method according to claim 1, characterized in that The concentration of the copper salt solution in step (1) is 0.05 to 0.15 mol / L.

4. The preparation method according to claim 1, characterized in that The pH value of the solution after adding ammonia water in step (1) is 11-13.

5. The preparation method according to claim 1, characterized in that The temperature of the deposition oxidation treatment in step (1) is 75 to 85° C.; the time of the deposition oxidation treatment is 6 to 8 hours.

6. The preparation method according to claim 1, characterized in that The heat treatment temperature in step (2) is 540-560° C., and the heat treatment time is 1-3 hours.

7. The preparation method according to claim 1 or 6, characterized in that The heating rate of heating to the heat treatment temperature in step (2) is 4 to 6°C / min.

8. The electrode material prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the electrode material according to claim 8 in electrocatalytic removal of nitrates in water.

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