Fullerol modified nano-array electrode material, and preparation method and application thereof

Abstract

This invention belongs to the field of electrocatalytic materials technology, specifically relating to a fullerol-modified nanoarray electrode material, its preparation method, and its application. This invention obtains fullerol-modified copper hydroxide nanomaterials by modifying the surface of a copper hydroxide nano-precursor material with fullerol, and finally, through a high-temperature gas-solid conversion reaction, obtains fullerol-modified copper-based compound nanomaterials. On the one hand, fullerol modulates the electronic structure of the copper-based material, thereby increasing the catalytic activity of Cu. + The species remain stable during the cathode electroreduction process; on the other hand, the fullerol's rich-OH groups can effectively regulate the interfacial water structure, reconstruct the hydrogen bond network, and promote water dissociation to generate active hydrogen. Benefiting from these advantages, the material prepared in this invention not only exhibits excellent electrocatalytic activity and selectivity in the field of electrocatalytic nitrate reduction to ammonia, but also demonstrates good long-term operational stability, providing a high-performance, low-cost electrocatalytic material solution for green ammonia synthesis technology.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalytic electrode materials technology. More specifically, it relates to a fullerol-modified nanoarray electrode material, its preparation method, and its application. Background Technology

[0002] Ammonia (NH3) is a crucial building block of modern industry, widely used in nitrogen fertilizers, pharmaceuticals, and polymer materials. However, current industrial ammonia synthesis relies entirely on the century-old Haber-Bosch process, which requires high temperature and pressure, consumes approximately 1% of global energy annually, and emits about 1.3% of anthropogenic carbon dioxide, sharply contradicting the "dual carbon" target. Therefore, developing green ammonia synthesis technology has become a strategic need in the global energy and catalysis sectors.

[0003] Electrocatalytic nitrate reduction to ammonia (NO3RR) technology is considered an ideal alternative to the Haber-Bosch process due to its advantages such as mild reaction conditions (room temperature and pressure), zero carbon emissions, and wide availability of raw materials (industrial / agricultural nitrates, nitrite wastewater). Among these, copper (Cu)-based materials are particularly advantageous due to their unique electronic structure—the highest occupied d orbital energy level is highly compatible with nitrate (NO3) groups. - The lowest unoccupied π orbital is highly matched, enabling efficient adsorption and activation of NO3. - It has become the most widely studied NO3RR catalyst to date.

[0004] Active hydrogen (*H) promotes NO3- - The key intermediate species reduced to NH3, however, existing copper-based materials generally suffer from insufficient ability to generate *H through water dissociation, hindering the reduction of NO2. - It is further reduced to NH3. Furthermore, previous studies have confirmed that the intermediate valence state Cu... + It is a key active site for NO3RR, but it is easily reduced to Cu under the negative potential environment of electrocatalytic reduction. 0 This leads to a decrease in catalytic activity.

[0005] Therefore, developing Cu with stable properties + High-performance copper-based NO3RR catalysts with active centers and strong water dissociation capabilities are of great significance for promoting the practical application of green ammonia synthesis technology. Summary of the Invention

[0006] This invention addresses the problems of low catalytic activity, poor product selectivity, and poor stability of existing copper-based materials in electrocatalytic nitrate reduction to ammonia (NO3RR). It aims to provide a fullerol-modified nanoarray electrode material, its preparation method, and its application.

[0007] The first objective of this invention is to provide a method for preparing fullerol-modified copper-based compound nanomaterials.

[0008] A second objective of this invention is to provide fullerol-modified copper-based compound nanomaterials prepared by the aforementioned preparation method.

[0009] A third objective of this invention is to provide the application of the fullerol-modified copper-based compound nanomaterials in the preparation of electrode catalytic materials.

[0010] The fourth objective of this invention is to provide an electrode catalytic material.

[0011] The fifth objective of this invention is to provide the application of the fullerol-modified copper-based compound nanomaterial or the electrode catalytic material in the electrocatalytic reduction of nitrate to ammonia.

[0012] The above-mentioned objective of this invention is achieved through the following technical solution:

[0013] This invention provides a method for preparing fullerol-modified copper-based compound nanomaterials, comprising the following steps: S1: Preparation of copper hydroxide nano-precursor materials; S2: Fullerol modification of the copper hydroxide nano precursor material obtained in S1 to obtain fullerol-modified copper hydroxide nanomaterials. S3: The fullerol-modified copper hydroxide nanomaterials obtained in S2 are brought into contact with a heat conversion source material, and a high-temperature gas-solid conversion reaction is carried out at 150~600 °C under a protective gas atmosphere to obtain fullerol-modified copper-based compound nanomaterials. The heat conversion source material includes at least one of phosphorus source, sulfur source, nitrogen source, tellurium source, and selenium source.

[0014] intermediate valence state Cu + As a key active site for NO3RR, it is easily reduced to Cu under the negative potential environment of electrocatalytic reduction. 0 This leads to reduced catalytic activity, a bottleneck restricting the improvement of catalytic performance. However, this invention creatively discovers that although fullerols themselves lack catalytic activity, copper-based nanomaterials modified with fullerols can not only accelerate water dissociation to generate *H, lower the deoxygenation and hydrogenation energy barrier of nitrogen-containing intermediates, thereby improving the directed formation of ammonia and simultaneously increasing the ammonia production rate and the Faradaic efficiency, but more importantly, fullerol modification also enhances the catalytic activity of Cu. + The species maintains a stable valence state during the NO3RR process, effectively inhibiting Cu. + Reduced to inert Cu 0 This avoids the deactivation of the catalyst's active center and significantly improves the long-term stability of the electrode; its performance improvement effect is better than that of copper-based compound nanomaterials modified with graphene oxide, which is also an oxide derivative of carbon nanomaterials.

[0015] Preferably, the preparation method of the copper hydroxide nano-precursor material includes an oxidative etching method or a hydrothermal synthesis method.

[0016] More preferably, the copper hydroxide nano-precursor material is prepared by an oxidation etching method.

[0017] Preferably, the oxidation etching method specifically includes the following steps: A copper-based current collector was placed in a mixed solution containing a precipitant and an oxidant for an oxidative etching reaction, followed by post-treatment to obtain copper hydroxide nano-precursor materials. This method provides a more convenient and faster way to synthesize copper hydroxide nanoarray precursor materials.

[0018] Preferably, in the specific steps of the oxidation etching method, the copper-based current collector includes a copper-containing material, specifically copper foam.

[0019] Preferably, in the specific steps of the oxidation etching method, the precipitant is selected from at least one of potassium hydroxide, sodium hydroxide, sodium carbonate, sodium bicarbonate, sodium oxalate, ammonia, urea, and hexamethylenetetramine.

[0020] More preferably, the precipitant is selected from at least one of urea, sodium oxalate, sodium hydroxide, potassium hydroxide, and sodium bicarbonate.

[0021] Preferably, in the specific steps of the oxidation etching method, the oxidant is selected from at least one of sodium persulfate, potassium persulfate, potassium peroxymonosulfate, ammonium persulfate, hydrogen peroxide, and hypochlorite.

[0022] More preferably, the oxidant is selected from at least one of sodium persulfate, hydrogen peroxide, potassium persulfate, and ammonium persulfate.

[0023] Preferably, in the specific steps of the oxidation etching method, the molar ratio of precipitant to oxidant is (2~30):1; more preferably, it is (4~25):1.

[0024] Preferably, in the specific steps of the oxidation etching method, the temperature of the oxidation etching is 20~90 ℃; more preferably, it is 30~70 ℃.

[0025] Preferably, in the specific steps of the oxidation etching method, the oxidation etching time is 1~60 h; more preferably, it is 2~48 h.

[0026] Preferably, in the specific steps of the oxidation etching method, the solvent of the mixed solution is selected from at least one of water, methanol, ethanol, isopropanol, ethylene glycol, and propylene glycol.

[0027] More preferably, in the specific steps of the oxidation etching method, the solvent is selected from at least one of water, methanol, ethanol, isopropanol, and ethylene glycol.

[0028] Preferably, in the specific steps of the oxidation etching method, the ratio of the amount of precipitant to the amount of solvent in the mixed solution is (2~10) mmol:1 mL; more preferably, it is (2.5~6.5) mmol:1 mL.

[0029] Preferably, in step S1, the post-processing includes cooling, washing, and drying.

[0030] Optionally, the washing process involves washing with water and anhydrous ethanol 2 to 4 times, optionally 3 times.

[0031] Optionally, the drying is performed at 50-70°C for 4-26 hours, or optionally at 60°C for 6-24 hours.

[0032] Preferably, in step S2, the modification specifically includes the following steps: placing the copper hydroxide nano-precursor material obtained in step S1 in a solvent containing fullerol for full reaction, followed by post-treatment to obtain the fullerol-modified copper hydroxide nano-material.

[0033] Specifically, in step S2, the fullerol is C 20+2k (OH) x , where k is an integer ≥ 0.

[0034] More preferably, the number of carbon atoms in the fullerol is 20+2k, where k is an integer of 20≤k≤32.

[0035] More preferably, in step S2, the fullerol is C 60 Type Fullerol, C 70 Type Fullerol, C 76 Type Fullerol, C 80 Type Fullerol, C 84 At least one of the fullerols.

[0036] Furthermore, the fullerol is prepared by commercial purchase or in-house preparation.

[0037] As an optional implementation, when prepared in-house, the fullerol is obtained from fullerene via an alkaline-catalyzed oxidation method, comprising the following steps: (1) Disperse fullerene in an organic solvent, add an alkaline solution, and allow it to react fully to obtain a mixed solution; (2) Add a phase transfer catalyst and an oxidant to the mixed solution in step (1), react fully, and then perform post-treatment to obtain the fullerol.

[0038] Optionally, in step (1), the organic solvent is selected from at least one of toluene, xylene, chlorobenzene, o-dichlorobenzene, carbon tetrachloride, and carbon disulfide.

[0039] Optionally, in step (1), the alkaline solution is selected from at least one of sodium hydroxide solution and potassium hydroxide solution.

[0040] Preferably, in step (1), the ratio of the fullerene to the organic solvent is (20~40) mg:100 mL; more preferably, it is 30 mg:100 mL.

[0041] Preferably, in step S1, the mass ratio of the alkaline solution to fullerene is 1:(50~100); more preferably, it is 1:(80~85).

[0042] Optionally, in step (2), the phase transfer catalyst comprises tetrabutylammonium hydroxide.

[0043] Optionally, in step (2), the oxidant includes hydrogen peroxide.

[0044] Preferably, in step (2), the ratio of the amount of phase transfer catalyst added per hour to the amount of fullerene is 1 mL: (100~150) mg; more preferably, it is 1 mL: 120 mg.

[0045] Preferably, in step (2), the volume ratio of the phase transfer catalyst to the oxidant is (1~2):(1~2); more preferably, it is 1:1.

[0046] Optionally, in step (2), the post-processing includes centrifugation and washing.

[0047] Specifically, in step (2), the washing involves washing with anhydrous ethanol 3 to 5 times, with 5 times being an option.

[0048] Under alkaline conditions, OH - As a nucleophile, it attacks the double bond of fullerene to generate a hydroxyl addition product. Due to the high symmetry and reactivity of the carbon atoms in fullerene, the hydroxyl addition process lacks site selectivity, resulting in a mixed system of fullerol homologues with different numbers of hydroxyl groups (the number of hydroxyl groups in fullerols is continuously distributed) rather than a compound with a single defined structure. Moreover, it is difficult to completely separate them by conventional separation methods (such as chromatography and crystallization). Therefore, the number of hydroxyl groups in fullerols cannot be accurately determined, so it is represented by x.

[0049] Preferably, in step S2, the modification involves placing the copper hydroxide nano-precursor material obtained in step S1 in a solvent containing fullerol for a full reaction, followed by post-treatment to obtain the fullerol-modified copper hydroxide nano-material.

[0050] Preferably, in the specific steps of the modification, the post-processing includes washing and drying.

[0051] Optionally, the washing process involves washing 2 to 4 times, preferably 3 times, using a first solvent and a second solvent respectively; the first solvent may be selected from at least one of ethanol, methanol, water, ethylene glycol, and propylene glycol; the second solvent may be selected from at least one of water and ethanol.

[0052] Optionally, the drying is performed at 50-70°C for 4-26 hours, or optionally at 60°C for 6-24 hours.

[0053] Preferably, in the specific steps of the modification, the concentration of fullerol in the solvent is 0.8~12 mmol / L; more preferably, it is 1~10 mmol / L.

[0054] Preferably, in the specific steps of the modification, the solvent is selected from at least one of water, methanol, ethanol, isopropanol, ethylene glycol, and propylene glycol.

[0055] More preferably, the solvent is selected from at least one of water, methanol, ethanol, ethylene glycol, and propylene glycol.

[0056] Preferably, in the specific steps of the modification, the temperature for the fullerol modification is 20~100 ℃; more preferably, it is 40~80 ℃.

[0057] Preferably, in the specific steps of the modification, the fullerol modification time is 6~100 h; more preferably, it is 12~96 h.

[0058] Optionally, in step S3, the protective gas is selected from at least one of argon (Ar), nitrogen (N2), and helium (He).

[0059] Optionally, in step S3, the protective gas is selected from at least one of nitrogen, argon, and helium.

[0060] Preferably, in step S3, the temperature of the high-temperature gas-solid conversion reaction is 150~700 ℃, more preferably 200~600 ℃.

[0061] Preferably, in step S3, the time for the high-temperature gas-solid conversion reaction is 2~48 h; more preferably, it is 4~36 h.

[0062] Preferably, in step S3, the heating rate of the high-temperature gas-solid conversion reaction is 1~25 ℃ / min; more preferably, it is 2~20 ℃ / min.

[0063] Preferably, in step S3, the mass ratio of the fullerol-modified copper hydroxide nanomaterial to the heat conversion source material is 1:(3~120), more preferably 1:(5~100).

[0064] Optionally, in step S3, the phosphorus source includes sodium hypophosphite and / or red phosphorus.

[0065] Optionally, in step S3, the sulfur source includes thiourea and / or thiols.

[0066] Optionally, in step S3, the nitrogen source includes urea and / or melamine.

[0067] Optionally, in step S3, the tellurium source includes tellurium powder.

[0068] Optionally, in step S3, the selenium source includes selenium powder.

[0069] The present invention also provides fullerol-modified copper-based compound nanomaterials prepared by the preparation method described above.

[0070] The present invention also provides the application of the fullerol-modified copper-based compound nanomaterials in the preparation of electrode catalytic materials.

[0071] The present invention also provides an electrode catalytic material comprising copper-based compound nanomaterials modified with fullerol.

[0072] When the fullerol-modified copper-based compound nanomaterials are used to directly prepare copper hydroxide nano-precursor materials on the current collector, that is, when the fullerol-modified copper-based compound nanomaterials are generated in situ on the current collector, the resulting fullerol-modified copper-based compound nanomaterials can be used as electrode catalytic materials.

[0073] When the fullerol-modified copper-based compound nanomaterial is a nanopowder prepared without the addition of a current collector, the electrode catalytic material further includes a substrate, on which the fullerol-modified copper-based compound nanomaterial is loaded.

[0074] Alternatively, the substrate may include electrodes.

[0075] Preferably, the electrode includes a copper electrode and a glassy carbon electrode, and specifically, it can be copper foam.

[0076] As an alternative implementation, the fullerol-modified copper-based compound nanomaterial is loaded onto a substrate by drop-addition or coating.

[0077] Furthermore, as an optional implementation, the electrode catalytic material is prepared by the following steps: The fullerol-modified copper-based compound nanomaterials were dispersed in a solvent to obtain a dispersion; the obtained dispersion was dropped onto a substrate and dried to obtain the electrode catalytic material.

[0078] The present invention also provides the application of the fullerol-modified copper-based compound nanomaterials or the electrode catalytic materials in the electrocatalytic reduction of nitrates to ammonia.

[0079] Furthermore, the electrocatalytic reduction of nitrate to ammonia involves reducing nitrate ions (NO3-) to ammonia. - ) and / or nitrite ions (NO2) - It is converted into ammonia (NH3).

[0080] Optionally, the electrocatalytic reduction of nitrate to produce ammonia includes electrolyzing a medium containing nitrate ions and / or nitrite ions, such as an aqueous solution containing nitrate ions and / or nitrite ions.

[0081] The present invention has the following beneficial effects: This invention modulates the electronic structure and surface properties of copper-based compounds through fullerol modification, constructing fullerol-modified copper-based compound nanomaterials that effectively solve the problems of insufficient hydrolysis generation of active hydrogen (*H) in traditional copper-based materials and Cu... + Despite the problem of easy loss of active sites, it exhibits excellent electrocatalytic activity and selectivity, as well as good long-term operational stability in the field of electrocatalytic nitrate reduction to ammonia (NO3RR), providing a high-performance and low-cost electrocatalytic material solution for green ammonia synthesis technology. Attached Figure Description

[0082] Figure 1 The CF / CuTe-C obtained in Example 1 80 (OH) x SEM image of nanoarray material.

[0083] Figure 2 The CF / CuS-C obtained in Example 2 84 (OH) x SEM image of nanoarray material.

[0084] Figure 3 The CF / Cu3N-C obtained in Example 3 76 (OH) x SEM image of nanoarray material.

[0085] Figure 4 The CF / Cu3P2-C obtained in Example 4 70 (OH) x SEM image of nanoarray material.

[0086] Figure 5 The CF / CuSe-C obtained in Example 5 60 (OH) x SEM image of nanoarray material.

[0087] Figure 6 The LSV diagram shows the electrocatalytic nitrate reduction to ammonia production reaction of the nanoarray materials obtained in Examples 1, 1, 6, 7 and 8.

[0088] Figure 7 The CF / CuTe-C obtained in Example 1 80 (OH) x The stability test results of CF / CuTe obtained in Comparative Example 1 are shown in the figure.

[0089] Figure 8 The LSV diagram shows the electrocatalytic nitrate reduction to ammonia production reaction of the nanoarray materials obtained in Example 2 and Comparative Example 2.

[0090] Figure 9 The LSV diagram shows the electrocatalytic nitrate reduction to ammonia production reaction of the nanoarray materials obtained in Example 3 and Comparative Example 3.

[0091] Figure 10 The LSV diagram shows the electrocatalytic nitrate reduction to ammonia production reaction of the nanoarray materials obtained in Example 4 and Comparative Example 4.

[0092] Figure 11 The LSV diagram shows the electrocatalytic nitrate reduction to ammonia production reaction of the nanoarray materials obtained in Example 5 and Comparative Example 5. Detailed Implementation

[0093] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field.

[0094] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0095] The carbon nanomaterials used in this invention are as follows: C 80 Fullerene: CAS: 133947-15-6; C 84 Fullerene: McLean, catalog number F708411; C 76 Fullerene: McLean, catalog number F708409; C 70 Fullerene: McLean, catalog number F699196; C 60 Fullerene: McLean, catalog number F698216; Graphene oxide (GO): Maclean, G864820; The fullerols used in the examples were prepared by existing base-catalyzed oxidation methods, with fullerol C80 (OH) x Taking this example, the synthesis steps are explained in detail. The preparation methods for other fullerols can be referenced in this process: 30 mg C 80 Fullerene was dispersed in 100 mL of toluene, followed by the addition of 5 mL of an aqueous solution containing 2.5 g NaOH, and stirred vigorously at room temperature. Then, 0.25 mL of tetrabutylammonium hydroxide and 0.25 mL of hydrogen peroxide were added hourly until the toluene became colorless, and stirring was continued for 12 h. The reaction mixture was centrifuged, and the resulting solid was washed five times with anhydrous ethanol to obtain fullerol C. 80 (OH) x .

[0096] Under alkaline conditions, OH - As a nucleophile, it attacks the double bond of fullerenes, generating hydroxyl addition products. Due to the high symmetry of the carbon atoms in fullerenes, the hydroxyl addition process lacks site selectivity, resulting in a mixed system of fullerol homologues with different numbers of hydroxyl groups (the number of hydroxyl groups x in fullerols exhibits a continuous distribution), rather than a single compound with a defined structure. Furthermore, it is difficult to completely separate these compounds using conventional methods (such as chromatography and crystallization), making it impossible to accurately quantify the average number of hydroxyl groups in fullerols. To facilitate the calculation of the amount of fullerol used, the number of hydroxyl groups is estimated based on a carbon-to-hydroxyl ratio of 5:2, and the molar mass of fullerol is determined accordingly.

[0097] Example 1 CF / CuTe-C 80 (OH) x Nanoarray materials The CF / CuTe-C 80 (OH) x The preparation method of nanoarray materials includes the following steps: (1) 42.3 g (500 mmol) sodium bicarbonate (NaHCO3) and 4.56 g (20 mmol) ammonium persulfate ((NH4)2S2O8) were dissolved in 80 mL of ethanol and stirred thoroughly on a stirrer for 6 h (stirrer speed was 600 rpm) to obtain a homogeneous mixed solution. Then, 3 pieces of 3×5 cm pretreated copper foam (CF) were immersed in the solution and oxidative etching reaction was carried out at 40 °C for 8 h. After the reaction was completed, the solution was allowed to cool naturally. The cooled material was washed 3 times with ultrapure water and anhydrous ethanol respectively, and dried in a forced-air drying oven at 60 °C for 6 h to obtain Cu(OH)2 nanoarray precursor material loaded on CF current collector. (2) Immerse the Cu(OH)₂ nanoarray precursor material loaded on the CF current collector obtained in step (1) into a 3 mmol / L solution with 50 mL of propylene glycol as the solvent. 80 (OH)x The solution was stirred at 80 °C for 72 h in a (0.226 g) solution, then washed three times with propylene glycol and anhydrous ethanol, and dried in a forced-air drying oven at 60 °C for 24 h to obtain Cu(OH)₂-C loaded on the CF current collector. 80 (OH) x Nanoarray materials; (3) Load Cu(OH)2-C onto the CF current collector obtained in step (2). 80 (OH) x The nanoarray material and tellurium powder (thermal conversion source material, tellurium source) were mixed at a mass ratio of 1:50 and placed in a nitrogen atmosphere at a nitrogen flow rate of 50 mL / min. The temperature was increased to 400 °C at a heating rate of 10 °C / min for 12 h for a high-temperature gas-solid conversion reaction. After the reaction, the mixture was naturally cooled to room temperature to obtain a fullerol-modified CuTe nanoarray material (CF / CuTe-C) supported on a CF current collector. 80 (OH) x ).

[0098] CF / CuTe-C was studied using scanning electron microscopy (SEM). 80 (OH) x Characterization was performed, and the results are as follows: Figure 1 As shown in the figure, a nanoarray structure is uniformly distributed on the CF current collector.

[0099] Example 2 CF / CuS-C 84 (OH) x Nanoarray materials The CF / CuS-C 84 (OH) x The preparation method of nanoarray materials includes the following steps: (1) Dissolve 7.01 g (125 mmol) potassium hydroxide (KOH) and 1.69 g (6.25 mmol) potassium persulfate (K2S2O8) in 50 mL of ultrapure water and stir thoroughly on a stirrer for 2 h (stirrer speed is 500 rpm) to obtain a homogeneous mixed solution. Then, immerse two 2×3 cm pretreated copper foam (CF) sheets in the solution and perform an oxidative etching reaction at 60 °C for 2 h. After the reaction is completed, allow it to cool naturally. The cooled material is washed three times with ultrapure water and anhydrous ethanol respectively, and then dried in a forced-air drying oven at 60 °C for 12 h to obtain Cu(OH)2 nanoarray precursor material loaded on CF current collector. (2) Immerse the Cu(OH)₂ nanoarray precursor material loaded on the CF current collector obtained in step (1) into a 1 mmol / L solution with 50 mL of ethylene glycol as the solvent.84 (OH) x The solution was stirred at 60 °C for 48 h in a (0.079 g) solution, then washed three times with ethylene glycol and ultrapure water respectively, and dried at 60 °C in a forced-air drying oven for 12 h to obtain Cu(OH)₂-C loaded on the CF current collector. 84 (OH) x Nanoarray materials; (3) Load Cu(OH)2-C onto the CF current collector obtained in step (2). 84 (OH) x The nanoarray material was mixed with thiourea (a heat conversion source, sulfur source) at a mass ratio of 1:20 and placed in an argon atmosphere at a flow rate of 30 mL / min. The temperature was increased to 300 °C at a rate of 5 °C / min for a high-temperature gas-solid conversion reaction for 24 h. After the reaction, the mixture was allowed to cool naturally to room temperature to obtain a fullerol-modified CuS nanoarray material (CF / CuS-C) supported on a CF current collector. 84 (OH) x ).

[0100] Using scanning electron microscopy, CF / CuS-C 84 (OH) x Characterization was performed, and the results are as follows: Figure 2 As shown in the figure, a nanoarray structure is uniformly distributed on the CF current collector.

[0101] Example 3CF / Cu3N-C 76 (OH) x Nanoarray materials The CF / Cu3N-C 76 (OH) x The preparation method of nanoarray materials includes the following steps: (1) Dissolve 10.3 g (250 mmol) sodium hydroxide (NaOH) and 10.20 g (60 mmol) hydrogen peroxide (H2O2, 30%wt) in 60 mL of isopropanol and stir thoroughly on a stirrer for 1 h (stirrer speed is 450 rpm) to obtain a homogeneous mixed solution. Then, immerse two 1×3 cm pretreated copper foam (CF) sheets in the solution and perform an oxidation etching reaction at 50 °C for 24 h. After the reaction is completed, allow it to cool naturally. The cooled material is washed three times with isopropanol and ultrapure water respectively, and then dried in a forced-air drying oven at 60 °C for 24 h to obtain Cu(OH)2 nanoarray precursor material loaded on CF current collector. (2) Immerse the Cu(OH)2 nanoarray precursor material loaded on the CF current collector obtained in step (1) in a 5 mmol / L solution with 50 mL of water as the solvent. 76 (OH)x The solution was stirred at 40 °C for 24 h in a (0.356 g) solution, then washed three times with ultrapure water and three times with anhydrous ethanol, and dried at 60 °C for 6 h in a forced-air drying oven to obtain Cu(OH)₂-C loaded on the CF current collector. 76 (OH) x Nanoarray materials; (3) Load Cu(OH)2-C onto the CF current collector obtained in step (2). 76 (OH) x The nanoarray material was mixed with urea (a heat conversion source, nitrogen source) at a mass ratio of 1:5 and placed in a nitrogen atmosphere at a nitrogen flow rate of 2 mL / min. The temperature was increased to 200 °C at a heating rate of 2 °C / min for 8 h for a high-temperature gas-solid conversion reaction. After the reaction, the mixture was naturally cooled to room temperature to obtain a fullerol-modified Cu3N nanoarray material (CF / Cu3N-C) supported on a CF current collector. 76 (OH) x ).

[0102] Using scanning electron microscopy, CF / Cu3N-C 76 (OH) x Characterization was performed, and the results are as follows: Figure 3 As shown in the figure, a nanoarray structure is uniformly distributed on the CF current collector.

[0103] Example 4 CF / Cu3P2-C 70 (OH) x Nanoarray materials The CF / Cu3P2-C 70 (OH) x The preparation method of nanoarray materials includes the following steps: (1) 53.6 g (400 mmol) sodium oxalate (Na2C2O4) and 3.81 g (16 mmol) sodium persulfate (Na2S2O8) were dissolved in 100 mL methanol and stirred thoroughly on a stirrer for 2 h (stirrer speed was 500 rpm) to obtain a homogeneous mixed solution. Four 2×3 cm pretreated copper foam (CF) sheets were then immersed in the solution and subjected to an oxidative etching reaction at 30 °C for 36 h. After the reaction was completed, the solution was allowed to cool naturally. The cooled material was washed three times with ultrapure water and anhydrous ethanol, and then dried in a forced-air drying oven at 60 °C for 12 h to obtain Cu(OH)2 nanoarray precursor material loaded on CF current collector. (2) Immerse the Cu(OH)₂ nanoarray precursor material loaded on the CF current collector obtained in step (1) into 8 mmol / L HCl with 50 mL methanol as solvent. 70 (OH) xThe solution was stirred at 60 °C for 96 h in a (0.527 g) solution, then washed three times with methanol and three times with ultrapure water, and dried in a forced-air drying oven at 60 °C for 12 h to obtain Cu(OH)₂-C loaded on the CF current collector. 70 (OH) x Nanoarray materials; (3) Load Cu(OH)2-C onto the CF current collector obtained in step (2). 70 (OH) x The nanoarray material was mixed with sodium hypophosphite (a heat conversion source, phosphorus source) at a mass ratio of 1:10 and placed in a helium atmosphere. The helium flow rate was 5 mL / min, and the temperature was increased to 600 °C at a heating rate of 15 °C / min for 4 h for a high-temperature gas-solid conversion reaction. After the reaction, the mixture was naturally cooled to room temperature to obtain a fullerol-modified Cu3P2 nanoarray material (CF / Cu3P2-C) supported on a CF current collector. 70 (OH) x ).

[0104] Using scanning electron microscopy, CF / Cu3P2-C 70 (OH) x Characterization was performed, and the results are as follows: Figure 4 As shown in the figure, a nanoarray structure is uniformly distributed on the CF current collector.

[0105] Example 5 CF / CuSe-C 60 (OH) x Nanoarray materials The CF / CuSe-C 60 (OH) x The preparation method of nanoarray materials includes the following steps: (1) Dissolve 19.2 g (320 mmol) urea (CH4N2O) and 3.40 g (14 mmol) potassium persulfate (KHSO5) in 100 mL of ethylene glycol and stir thoroughly on a stirrer for 12 h (stirrer speed is 650 rpm) to obtain a homogeneous mixed solution. Then, immerse 4 pieces of 3×4 cm pretreated copper foam (CF) in it and carry out an oxidation etching reaction at 70 °C for 48 h. After the reaction is completed, allow it to cool naturally. The cooled material is washed 3 times with ethylene glycol and ultrapure water respectively, and dried in a forced-air drying oven at 60 °C for 24 h to obtain Cu(OH)2 nanoarray precursor material loaded on CF current collector; (2) Immerse the Cu(OH)₂ nanoarray precursor material loaded on the CF current collector obtained in step (1) into a 10 mmol / L solution with 50 mL of ethanol as the solvent. 60 (OH) xThe solution was stirred at 70 °C for 12 h in a (0.564 g) solution, then washed three times with ethanol and three times with ultrapure water, and dried in a forced-air drying oven at 60 °C for 24 h to obtain Cu(OH)₂-C loaded on the CF current collector. 60 (OH) x Nanoarray materials; (3) Load Cu(OH)2-C onto the CF current collector obtained in step (2). 60 (OH) x The nanoarray material was mixed with selenium powder (a heat conversion source, selenium source) at a mass ratio of 1:100 and placed in an argon-nitrogen mixed atmosphere (volume ratio 1:1) at a gas flow rate of 80 mL / min. The temperature was increased to 500 °C at a heating rate of 20 °C / min for 36 h for a high-temperature gas-solid conversion reaction. After the reaction, the mixture was allowed to cool naturally to room temperature to obtain a fullerol-modified CuSe nanoarray material (CF / CuSe-C) supported on a CF current collector. 60 (OH) x ).

[0106] Using scanning electron microscopy, CF / CuSe-C 60 (OH) x Characterization was performed, and the results are as follows: Figure 5 As shown in the figure, a nanoarray structure is uniformly distributed on the CF current collector.

[0107] Comparative Example 1: CF / CuTe Nanoarray Material The difference from Example 1 is that fullerol C was not performed. 80 (OH) x The modification and other steps are the same as in Example 1. The preparation method of the CF / CuTe nanoarray material includes the following steps: (1) 42.3 g (500 mmol) sodium bicarbonate (NaHCO3) and 4.56 g (20 mmol) ammonium persulfate ((NH4)2S2O8) were dissolved in 80 mL of ethanol and stirred thoroughly on a stirrer for 6 h (stirrer speed was 600 rpm) to obtain a homogeneous mixed solution. Then, 3 pieces of 3×5 cm pretreated copper foam (CF) were immersed in the solution and oxidative etching reaction was carried out at 40 °C for 8 h. After the reaction was completed, the solution was allowed to cool naturally. The cooled material was washed 3 times with ultrapure water and anhydrous ethanol respectively, and dried in a forced-air drying oven at 60 °C for 6 h to obtain Cu(OH)2 nanoarray precursor material loaded on CF current collector. (2) The Cu(OH)2 nanoarray precursor material loaded on the CF current collector obtained in step (1) is mixed with tellurium powder (thermal conversion source material, tellurium source) at a mass ratio of 1:50, placed in a nitrogen atmosphere, the nitrogen flow rate is 50 mL / min, the temperature is raised to 400 ℃ at a heating rate of 10 ℃ / min, and a high-temperature gas-solid conversion reaction is carried out for 12 h. After the reaction is completed, it is naturally cooled to room temperature to obtain CuTe nanoarray material loaded on the CF current collector (CF / CuTe).

[0108] Comparative Example 2: CF / CuS Nanoarray Material The difference from Example 2 is that fullerol C was not performed. 84 (OH) x The modification and other steps are the same as in Example 2. The preparation method of the CF / CuS nanoarray material includes the following steps: (1) Dissolve 7.01 g (125 mmol) potassium hydroxide (KOH) and 1.69 g (6.25 mmol) potassium persulfate (K2S2O8) in 50 mL of ultrapure water, stir thoroughly on a stirrer for 2 h (stirrer speed is 500 rpm) to obtain a homogeneous mixed solution, then immerse two 2×3 cm pretreated copper foam (CF) sheets in it, and carry out an oxidation etching reaction at 60 ℃ for 2 h. After the reaction is completed, allow it to cool naturally. The cooled material is washed three times with ultrapure water and anhydrous ethanol respectively, and then dried in a forced-air drying oven at 60 ℃ for 12 h to obtain Cu(OH)2 nanoarray precursor material loaded on CF current collector; (2) The Cu(OH)2 nanoarray precursor material loaded on the CF current collector obtained in step (1) is mixed with thiourea (thermal conversion source material, sulfur source) at a mass ratio of 1:20, placed in an argon atmosphere, with an argon flow rate of 30 mL / min, and heated to 300 ℃ at a heating rate of 5 ℃ / min for a high-temperature gas-solid conversion reaction for 24 h. After the reaction is completed, it is naturally cooled to room temperature to obtain CuS nanoarray material loaded on the CF current collector (CF / CuS).

[0109] Comparative Example 3: CF / Cu3N Nanoarray Material The difference from Example 3 is that fullerol C was not performed. 76 (OH) x The modification and other steps are the same as in Example 3. The preparation method of the CF / Cu3N nanoarray material includes the following steps: (1) Dissolve 10.3 g (250 mmol) sodium hydroxide (NaOH) and 10.20 g (60 mmol) hydrogen peroxide (H2O2, 30%wt) in 60 mL of isopropanol and stir thoroughly on a stirrer for 1 h (stirrer speed is 450 rpm) to obtain a homogeneous mixed solution. Then, immerse two 1×3 cm pretreated copper foam (CF) sheets in the solution and perform an oxidation etching reaction at 50 °C for 24 h. After the reaction is completed, allow it to cool naturally. The cooled material is washed three times with isopropanol and ultrapure water respectively, and then dried in a forced-air drying oven at 60 °C for 24 h to obtain Cu(OH)2 nanoarray precursor material loaded on CF current collector. (2) The Cu(OH)2 nanoarray precursor material loaded on the CF current collector obtained in step (1) was mixed with urea (thermal conversion source material, nitrogen source) at a mass ratio of 1:5, placed in a nitrogen atmosphere, the nitrogen flow rate was 2 mL / min, and the temperature was raised to 200 ℃ at a heating rate of 2 ℃ / min for 8 h of high-temperature gas-solid conversion reaction. After the reaction was completed, it was naturally cooled to room temperature to obtain Cu3N nanoarray material loaded on the CF current collector (CF / Cu3N). Comparative Example 4: CF / Cu3P2 Nanoarray Material The difference from Example 4 is that fullerol C was not performed. 70 (OH) x The modification and other steps are the same as in Example 4. The preparation method of the CF / Cu3P2 nanoarray material includes the following steps: (1) 53.6 g (400 mmol) sodium oxalate (Na2C2O4) and 3.81 g (16 mmol) sodium persulfate (Na2S2O8) were dissolved in 100 mL methanol and stirred thoroughly on a stirrer for 2 h (stirrer speed was 500 rpm) to obtain a homogeneous mixed solution. Four 2×3 cm pretreated copper foam (CF) sheets were then immersed in the solution and subjected to an oxidative etching reaction at 30 °C for 36 h. After the reaction was completed, the solution was allowed to cool naturally. The cooled material was washed three times with ultrapure water and anhydrous ethanol, and then dried in a forced-air drying oven at 60 °C for 12 h to obtain Cu(OH)2 nanoarray precursor material loaded on CF current collector. (2) The Cu(OH)2 nanoarray precursor material loaded on the CF current collector obtained in step (1) is mixed with sodium hypophosphite (thermal conversion source material, phosphorus source) at a mass ratio of 1:10, placed in a helium atmosphere, the helium flow rate is 5 mL / min, the temperature is raised to 600 ℃ at a heating rate of 15℃ / min, and a high-temperature gas-solid conversion reaction is carried out for 4 h. After the reaction is completed, it is naturally cooled to room temperature to obtain Cu3P2 nanoarray material loaded on the CF current collector (CF / Cu3P2).

[0110] Comparative Example 5: CF / CuSe Nanoarray Material The difference from Example 5 is that fullerol C was not performed. 60 (OH) x The modification and other steps are the same as in Example 5. The preparation method of the CF / CuSe nanoarray material includes the following steps: (1) Dissolve 19.2 g (320 mmol) urea (CH4N2O) and 3.40 g (14 mmol) potassium persulfate (KHSO5) in 100 mL of ethylene glycol and stir thoroughly on a stirrer for 12 h (stirrer speed is 650 rpm) to obtain a homogeneous mixed solution. Then, immerse 4 pieces of 3×4 cm pretreated copper foam (CF) in it and carry out an oxidation etching reaction at 70 °C for 48 h. After the reaction is completed, allow it to cool naturally. The cooled material is washed 3 times with ethylene glycol and ultrapure water respectively, and dried in a forced-air drying oven at 60 °C for 24 h to obtain Cu(OH)2 nanoarray precursor material loaded on CF current collector; (2) The Cu(OH)2 nanoarray precursor material loaded on the CF current collector obtained in step (1) is mixed with selenium powder (thermal conversion source material, selenium source) at a mass ratio of 1:100 and placed in an argon-nitrogen mixed atmosphere (volume ratio 1:1). The mixing gas flow rate is 80 mL / min, and the temperature is raised to 500 ℃ at a heating rate of 20 ℃ / min for 36 h of high-temperature gas-solid conversion reaction. After the reaction is completed, it is naturally cooled to room temperature to obtain CuSe nanoarray material loaded on the CF current collector (CF / CuSe).

[0111] Comparative Example 6: CF / Cu(OH)₂ nanoarray material The difference from Example 1 is that fullerol C was not performed. 80 (OH) x The modification and high-temperature gas-solid conversion, along with other steps as in Example 1, the preparation method of the CF / Cu(OH)2 nanoarray material includes the following steps: 42.3 g (500 mmol) sodium bicarbonate (NaHCO3) and 4.56 g (20 mmol) ammonium persulfate ((NH4)2S2O8) were dissolved in 80 mL of ethanol and stirred thoroughly on a stirrer for 6 h (stirrer speed 600 rpm) to obtain a homogeneous mixed solution. Then, three 3×5 cm pretreated copper foam (CF) sheets were immersed in the solution and subjected to an oxidative etching reaction at 40 °C for 8 h. After the reaction was completed, the solution was allowed to cool naturally. The cooled material was washed three times with ultrapure water and anhydrous ethanol, respectively, and then dried in a forced-air drying oven at 60 °C for 6 h to obtain Cu(OH)2 nanoarray material loaded on CF current collector.

[0112] Comparative Example 7 CF / Cu(OH)2-C80 (OH) x Nanoarray materials The difference from Example 1 is that no high-temperature gas-solid conversion was performed; the other steps are the same as in Example 1. The CF / Cu(OH)₂-C 80 (OH) x The preparation method of nanoarray materials includes the following steps: (1) 42.3 g (500 mmol) sodium bicarbonate (NaHCO3) and 4.56 g (20 mmol) ammonium persulfate ((NH4)2S2O8) were dissolved in 80 mL of ethanol and stirred thoroughly on a stirrer for 6 h (stirrer speed was 600 rpm) to obtain a homogeneous mixed solution. Then, 3 pieces of 3×5 cm pretreated copper foam (CF) were immersed in the solution and oxidative etching reaction was carried out at 40 °C for 8 h. After the reaction was completed, the solution was allowed to cool naturally. The cooled material was washed 3 times with ultrapure water and anhydrous ethanol respectively, and dried in a forced-air drying oven at 60 °C for 6 h to obtain Cu(OH)2 nanoarray precursor material loaded on CF current collector. (2) Immerse the Cu(OH)₂ nanoarray precursor material loaded on the CF current collector obtained in step (1) into a 3 mmol / L solution with 50 mL of propylene glycol as the solvent. 80 (OH) x The solution was stirred at 80 °C for 72 h in a (0.226 g) solution, then washed three times with propylene glycol and anhydrous ethanol, and dried in a forced-air drying oven at 60 °C for 24 h to obtain Cu(OH)₂-C loaded on the CF current collector. 80 (OH) x Nanoarray materials.

[0113] Comparative Example 8: CF / CuTe-GO Nanoarray Material The difference from Example 1 is that fullerol C is used. 80 (OH) x The modification was replaced with equimolar amounts of graphene oxide (GO), and the other steps were the same as in Example 1. The preparation method of the CF / CuTe-GO nanoarray material includes the following steps: (1) 42.3 g (500 mmol) sodium bicarbonate (NaHCO3) and 4.56 g (20 mmol) ammonium persulfate ((NH4)2S2O8) were dissolved in 80 mL of ethanol and stirred thoroughly on a stirrer for 6 h (stirrer speed was 600 rpm) to obtain a homogeneous mixed solution. Then, 3 pieces of 3×5 cm pretreated copper foam (CF) were immersed in the solution and oxidative etching reaction was carried out at 40 °C for 8 h. After the reaction was completed, the solution was allowed to cool naturally. The cooled material was washed 3 times with ultrapure water and anhydrous ethanol respectively, and dried in a forced-air drying oven at 60 °C for 6 h to obtain Cu(OH)2 nanoarray precursor material loaded on CF current collector. (2) The Cu(OH)2 nanoarray precursor material loaded on the CF current collector obtained in step (1) was immersed in a 3 mmol / L (molar mass based on 2043.9 g / mol) graphene oxide (GO) solution with propylene glycol as solvent, stirred at 80 °C for 72 h, then washed three times with propylene glycol and anhydrous ethanol respectively, and dried in a forced-air drying oven at 60 °C for 24 h to obtain Cu(OH)2-GO nanoarray material loaded on the CF current collector; (3) The Cu(OH)2-GO nanoarray material loaded on the CF current collector obtained in step (2) was mixed with tellurium powder (thermal conversion source material, tellurium source) at a mass ratio of 1:50, placed in a nitrogen atmosphere, the nitrogen flow rate was 50 mL / min, and the temperature was raised to 400 ℃ at a heating rate of 10 ℃ / min for a high-temperature gas-solid conversion reaction for 12 h. After the reaction was completed, it was naturally cooled to room temperature to obtain the CuTe nanoarray material modified with graphene oxide (GO) loaded on the CF current collector (CF / CuTe-GO).

[0114] Comparative Example 9 CC / C 80 (OH) x Nanomaterials The CC / C 80 (OH) x The preparation method of nanoarray materials includes the following steps: The pretreated carbon cloth (CC) was immersed in a 3 mmol / L solution with propylene glycol as the solvent. 80 (OH) x The solution was stirred at 80 °C for 72 h, then washed three times with propylene glycol and anhydrous ethanol, and dried in a forced-air drying oven at 60 °C for 24 h to obtain C loaded on the CC current collector. 80 (OH) x Nanomaterials.

[0115] Application Example 1: Performance Test of Electrocatalytic Nitrate Reduction for Ammonia Production Electrochemical tests were performed using a Koster electrochemical workstation with a standard three-electrode system. The main indicators for evaluating the activity of the nanoarray materials prepared in the examples or comparative examples were: the current (J) that can be excited at the same voltage or the voltage (E) required to reach the same current density, the ammonia production rate, and the Faraday efficiency.

[0116] The nanoarray material prepared in the examples or comparative examples was used as the working electrode (1×1 cm). 2 Pt sheet (1×1 cm) 2 To study the electrocatalytic performance of nanoarray materials in a three-electrode system with the counter electrode and the Hg / HgO electrode as the reference electrode, the electrolyte used was a mixed solution containing potassium nitrate and potassium hydroxide (1 M KOH + 0.1 M KNO3).

[0117] Before each electrochemical data acquisition, the solution resistance (Rs) values ​​of all materials were collected at open-circuit potential. CV curves were scanned multiple times within the voltage range of -1.3 to 0 V vs. Hg / HgO until stable. Then, LSV tests were performed within the same voltage range, and the LSV curves were compensated for 80% IR. The potential value E(Hg / HgO) was converted to E(RHE) according to the formula E(RHE) = E(Hg / HgO) + 0.098 + 0.05916 × pH. Furthermore, the electrocatalytic nitrate reduction to ammonia production performance of the materials was tested for 1 h using chronoamperometry (CA test), and the ammonia products (NH3, NH4) were analyzed using a UV-Vis spectrophotometer. + Quantitative analysis was performed.

[0118] Ammonia production testing procedure: Specific test procedure: After the CA test, 100 μL of the reaction solution was drawn with a syringe and diluted in 9.5 mL of deionized water. Then, 200 μL of potassium sodium tartrate solution (500 g / L) was added to the solution, followed by 200 μL of Nessler's reagent. After standing at room temperature for 20 min to stabilize, the solution was tested using a UV spectrophotometer. The characteristic peak was located at 420 nm. The NH3-N content in the solution (NH3-N: in aqueous solution, it exists as free ammonia (NH3) and ammonium ions (NH4)) can be obtained by referring to the prepared NH4Cl standard curve. + The total amount of nitrogen in the form of NH3. The Faraday efficiency and yield of NH3 can be calculated using the following formula:

[0119] In the formula, F is the Faraday constant, 96485 C / mol; C NH3 The mass concentration of NH3 in the aqueous solution (g / L); V represents the total volume of the electrolyte, in L; i is the current density, A / cm² 2 ; t is the electrolysis time, in hours; M NH3 Expresses the molar mass of NH3, in g / mol; Q represents the total charge passing through the electrode, C; A is the area of ​​the electrode, in cm² -2 .

[0120] The CF / CuTe-C obtained in Example 1 80 (OH) x Comparative Example 1: CF / CuTe; Comparative Example 6: CF / Cu(OH)2; Comparative Example 7: CF / Cu(OH)2-C 80 (OH) x Comparative Example 8 yielded CF / CuTe-GO and Comparative Example 9 yielded CC / C 80 (OH) x The electrocatalytic performance of nitrate reduction to ammonia production was tested; LSV results are available in [reference needed]. Figure 6 .Depend on Figure 6 It is evident that fullerols themselves do not exhibit any NO3RR response in the electrocatalytic reduction of nitrates to ammonia (NO3RR). Specifically, their electrocatalytic activity order is C C / C. 80 (OH) x <CF / Cu(OH)2<CF / Cu(OH)2-C 80 (OH) x <CF / CuTe<CF / CuTe-GO<CF / CuTe-C 80 (OH) x This demonstrates that the nanoarray material prepared in the embodiments of the present invention possesses superior electrocatalytic activity.

[0121] According to the UV-Vis spectrophotometer test, the CF / CuTe-C obtained in Example 1 80 (OH) x The ammonia formation rate at -0.2 V vs. RHE was 2.23 mmol h⁻¹ -1 cm -2 The Faraday efficiency was 96.1%; the ammonia production rate of CF / CuTe-GO obtained in Comparative Example 8 was 1.49 mmol / h at -0.2 V vs. RHE. -1 cm -2 The Faraday efficiency was 73.3%; the ammonia formation rate of CF / CuTe obtained in Comparative Example 1 was 0.92 mmol / h at -0.2 V vs. RHE. -1 cm-2 The Faraday efficiency was 60.6%; the ammonia formation rate of CF / Cu(OH)₂ obtained in Comparative Example 6 was 0.63 mmol / h at -0.2 V vs. RHE. -1 cm -2 The Faraday efficiency was 47.5%; the CF / Cu(OH)2-C obtained in Comparative Example 7 80 (OH) x The ammonia formation rate was 0.79 mmol / h at -0.2 V vs. RHE. -1 cm -2 The Faraday efficiency is 58.4%. Based on the above performance results, the order of their electrocatalytic performance in nitrate reduction to ammonia production is CF / Cu(OH)₂. <CF / Cu(OH)2-C 80 (OH) x <CF / CuTe<CF / CuTe-GO<CF / CuTe-C 80 (OH) x .

[0122] For Example 1 (CF / CuTe-C) 80 (OH) x The electrocatalytic stability of nitrate reduction to ammonia production in Comparative Example 1 (CF / CuTe) was tested, and the results are shown in [reference needed]. Figure 7 .Depend on Figure 7 It can be seen that CF / CuTe-C 80 (OH) x The ammonia production rate and Faraday efficiency remained at a high level after 10 tests, while the activity of CF / CuTe without fullerol modification decreased significantly.

[0123] In summary, fullerol itself does not exhibit any NO3RR response; and the nitrate reduction ammonia production performance of fullerol-modified Cu(OH)2 nanomaterials is far inferior to that of fullerol-modified CF / CuTe. This is presumably due to the poor conductivity of copper hydroxide and its weak adsorption to fullerol; furthermore, the performance of graphene oxide-modified CF / CuTe is also inferior to that of fullerol-modified CF / CuTe, indicating that fullerol-modified materials have better electrocatalytic nitrate reduction ammonia production performance compared to graphene oxide-modified materials.

[0124] Application Example 2: Performance Testing of Electrocatalytic Reduction of Nitrate to Ammonia (NO3RR) The CF / CuS-C obtained in Example 2 84 (OH) x The NO3RR performance of CF / CuS obtained in Comparative Example 2 was tested, and the LSV results are shown in [reference]. Figure 8A CA test was performed for 1 h at -0.35 V vs. RHE. After completion, samples were taken for UV-vis testing to obtain the concentration of NH3 and to calculate the ammonia production rate and Faraday efficiency. The specific test and calculation procedures are described in Application Example 1.

[0125] Depend on Figure 8 It can be seen that, for the electrocatalytic performance of nitrate reduction to ammonia production, the order of their electrocatalytic activity is CF / CuS. <CF / CuS-C 84 (OH) x This demonstrates that the nanoarray material prepared in the embodiments of the present invention possesses superior electrocatalytic activity.

[0126] According to the UV-Vis spectrophotometer test, the CF / CuS-C obtained in Example 2 84 (OH) x The ammonia formation rate at -0.35 V vs. RHE was 2.76 mmol h⁻¹. -1 cm -2 The Faraday efficiency was 95.7%; the ammonia formation rate of CF / CuS obtained in Comparative Example 2 was 0.97 mmol / h at -0.35 V vs. RHE. -1 cm -2 The Faraday efficiency is 57.4%. Based on the above performance results, it is evident that the electrocatalytic performance of the material obtained in Example 2 for nitrate reduction to ammonia production is significantly better than that of the material obtained in Comparative Example 2.

[0127] Application Example 3: Performance Testing of Electrocatalytic Reduction of Nitrate to Ammonia (NO3RR) The CF / Cu3N-C obtained in Example 3 76 (OH) x The NO3RR performance of CF / Cu3N obtained in Comparative Example 3 was tested, and the LSV results are shown in [reference]. Figure 9 A CA test was performed for 1 h at -0.3 V vs. RHE. After completion, samples were taken for UV-vis testing to obtain the concentration of NH3 and to calculate the ammonia production rate and Faraday efficiency. The specific test and calculation procedures are described in Application Example 1.

[0128] Depend on Figure 9 It can be seen that, for the electrocatalytic reduction of nitrate to ammonia, their electrocatalytic activity order is CF / Cu3N. <CF / Cu3N-C 76 (OH) x This demonstrates that the nanoarray material prepared in the embodiments of the present invention possesses superior electrocatalytic activity.

[0129] According to the UV-Vis spectrophotometer test, the CF / Cu3N-C obtained in Example 3 76 (OH) xThe ammonia formation rate at -0.3 V vs. RHE was 3.30 mmol h⁻¹ -1 cm -2 The Faraday efficiency was 98.6%; the ammonia formation rate of CF / Cu3N obtained in Comparative Example 3 was 1.20 mmol / h at -0.3V vs. RHE. -1 cm -2 The Faraday efficiency was 59.8%. Based on the above performance results, it is evident that the electrocatalytic performance of the material obtained in Example 3 for nitrate reduction to ammonia production is significantly better than that of the material obtained in Comparative Example 3.

[0130] Application Example 4: Performance Testing of Electrocatalytic Reduction of Nitrate to Ammonia (NO3RR) The CF / Cu3P2-C obtained in Example 4 70 (OH) x The NO3RR performance of CF / Cu3P2 obtained in Comparative Example 4 was tested, and the LSV results are shown in [reference]. Figure 10 A CA test was performed for 1 h at -0.2 V vs. RHE. After completion, samples were taken for UV-vis testing to obtain the concentration of NH3 and to calculate the ammonia production rate and Faraday efficiency. The specific test and calculation procedures are described in Application Example 1.

[0131] Depend on Figure 10 It is evident that, for the electrocatalytic reduction of nitrate to ammonia, their electrocatalytic activity order is CF / Cu3P2. <CF / Cu3P2-C 70 (OH) x This preliminary analysis indicates that the nanoarray material prepared in the embodiments of the present invention possesses superior electrocatalytic activity.

[0132] According to the UV-Vis spectrophotometer test, the CF / Cu3P2-C obtained in Example 4 70 (OH) x The ammonia formation rate at -0.2 V vs. RHE was 2.38 mmol h⁻¹ -1 cm -2 The Faraday efficiency was 95.2%; the ammonia formation rate of CF / Cu3P2 obtained in Comparative Example 4 was 1.03 mmol / h at -0.2 V vs. RHE. -1 cm -2 The Faraday efficiency was 57.2%. Based on the above performance results, it is evident that the electrocatalytic performance of the material obtained in Example 4 for nitrate reduction to ammonia production is significantly better than that of the material obtained in Comparative Example 4.

[0133] Application Example 5: Performance Testing of Electrocatalytic Reduction of Nitrate to Ammonia (NO3RR) The CF / CuSe-C obtained in Example 5 60 (OH)x The NO3RR performance of CF / CuSe obtained in Comparative Example 5 was tested, and the LSV results are shown in [reference]. Figure 11 A CA test was performed for 1 h at -0.25 V vs. RHE. After completion, samples were taken for UV-vis testing to obtain the concentration of NH3 and to calculate the ammonia production rate and Faraday efficiency. The specific test and calculation procedures are described in Application Example 1.

[0134] Depend on Figure 11 It can be seen that, for the electrocatalytic performance of nitrate reduction to ammonia production, the order of their electrocatalytic activity is CF / CuSe. <CF / CuSe-C 60 (OH) x This demonstrates that the nanoarray material prepared in the embodiments of the present invention possesses superior electrocatalytic activity.

[0135] According to the UV-Vis spectrophotometer test, the CF / CuSe-C obtained in Example 5 60 (OH) x The ammonia formation rate at -0.25 V vs. RHE was 3.12 mmol h⁻¹ -1 cm -2 The Faraday efficiency was 94.8%; the ammonia formation rate of CF / CuSe obtained in Comparative Example 5 was 1.33 mmol / h at -0.25 V vs. RHE. -1 cm -2 The Faraday efficiency is 62.3%. Based on the above performance results, it is evident that the electrocatalytic performance of the material obtained in Example 5 for nitrate reduction to ammonia production is significantly better than that of the material obtained in Comparative Example 5.

[0136] In summary, this invention obtains fullerol-modified copper hydroxide nanoarray materials by modifying the surface of copper hydroxide nanoarrays with fullerols, and finally obtains fullerol-modified copper-based compound nanoarray materials through a high-temperature gas-solid conversion reaction. On the one hand, fullerols modulate the electronic structure of copper-based materials, thereby increasing the catalytic activity of Cu... + The species remain stable during the cathode electroreduction process; on the other hand, the rich -OH groups of fullerol can effectively regulate the interfacial water structure, reconstruct the hydrogen bond network, and promote water dissociation to generate active hydrogen. Benefiting from these advantages, the material prepared in this invention not only exhibits excellent electrocatalytic activity and selectivity in the field of electrocatalytic nitrate reduction to ammonia, but also demonstrates good long-term operational stability, providing a high-performance, low-cost electrocatalytic material solution for green ammonia synthesis technology.

[0137] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing fullerol-modified copper-based compound nanomaterials, characterized in that, Includes the following steps: S1: Preparation of copper hydroxide nano-precursor materials; S2: Fullerol modification of the copper hydroxide nano precursor material obtained in S1 to obtain fullerol-modified copper hydroxide nanomaterials. S3: The fullerol-modified copper hydroxide nanomaterials obtained in S2 are brought into contact with a heat conversion source material, and a high-temperature gas-solid conversion reaction is carried out at 150~600 °C under a protective gas atmosphere to obtain fullerol-modified copper-based compound nanomaterials. The heat conversion source material includes at least one of phosphorus source, sulfur source, nitrogen source, tellurium source, and selenium source.

2. The preparation method according to claim 1, characterized in that, In step S2, the modification includes the following steps: placing the copper hydroxide nano-precursor material obtained in step S1 in a solvent containing fullerol for full reaction, followed by post-treatment to obtain the fullerol-modified copper hydroxide nano-material.

3. The preparation method according to claim 1, characterized in that, The fullerol contains 20+2k carbon atoms, where k is an integer 20≤k≤32.

4. The preparation method according to claim 1, characterized in that, The preparation methods of the copper hydroxide nano-precursor material include oxidative etching or hydrothermal synthesis.

5. The preparation method according to claim 4, characterized in that, The oxidation etching method specifically includes the following steps: A copper-based current collector was placed in a mixed solution containing a precipitant and an oxidant to carry out an oxidation etching reaction. After post-treatment, copper hydroxide nano-precursor material was obtained.

6. The preparation method according to claim 5, characterized in that, The parameters of the oxidation etching method include at least one of the following: (1) The precipitant is selected from at least one of potassium hydroxide, sodium hydroxide, sodium carbonate, sodium bicarbonate, sodium oxalate, ammonia, urea, and hexamethylenetetramine; (2) The oxidant is selected from at least one of sodium persulfate, potassium persulfate, potassium perhydrosulfate, ammonium persulfate, hydrogen peroxide, and hypochlorite.

7. Fullerol-modified copper-based compound nanomaterials prepared by the preparation method according to any one of claims 1 to 6.

8. The application of the fullerol-modified copper-based compound nanomaterials of claim 7 in the preparation of electrode catalytic materials.

9. An electrode catalytic material, characterized in that, Copper-based compound nanomaterials containing the fullerol modified according to claim 7.

10. The application of the fullerol-modified copper-based compound nanomaterial of claim 7 or the electrode catalytic material of claim 9 in the electrocatalytic reduction of nitrate to ammonia.

Images