Double-site Cu-based catalyst for synthesizing ammonia by electrocatalytic reduction of nitrogenous contamination / N2O, and preparation method and application of double-site Cu-based catalyst

Abstract

The invention provides a double-site Cu-based catalyst for electrocatalytic reduction of nitrogen-containing pollutants / N2O to synthesize ammonia and a preparation method and application thereof.The preparation method comprises the following steps that S1, polymeric carbon is dissolved in an organic solvent to obtain a mixed solution A, a Cu2O catalyst is soaked in the mixed solution A to obtain a mixed solution B, and the mixed solution B is subjected to electrocatalytic reduction to obtain a Cu-based catalyst; heating the mixed solution B to volatilize the organic solvent to obtain polymerized carbon / Cu2O powder; wherein the dosage of the polymeric carbon is 1%-10% of the mass of the Cu2O catalyst; and S2, grinding the polymeric carbon / Cu2O powder, annealing in an inert atmosphere, and cooling to obtain the polymeric carbon / Cu2O catalyst. Polymeric carbon is introduced into the Cu2O catalyst, so that the adsorption strength of nitrogen-containing pollutants and nitrogen intermediates and the dissociation strength of H2O can be balanced, and the performance of synthesizing NH3 through electro-catalytic reduction of the nitrogen-containing pollutants / N2O by the Cu-based catalyst is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalysis and relates to a dual-site Cu-based catalyst for electrocatalytic reduction of nitrogen-containing pollutants / N2O to synthesize ammonia, as well as a preparation method and application thereof. Background Art

[0002] Industrial production will emit a large amount of NO x Waste gas and N2O greenhouse gas. NO x It is an important precursor to environmental problems such as photochemical smog, low-level ozone, haze, acid rain, and eutrophication of water bodies. N2O can cause ozone layer destruction. x The reduction of NO and N2O emissions is urgent. x Catalytic reduction and catalytic decomposition are used to convert NO into harmless N2. However, these methods often require high temperatures above 350°C, which consumes considerable energy. x A large amount of NO3 will be produced – and NO2 – Wastewater.

[0003] By utilizing discarded "green electricity" to drive electrocatalysis, all nitrogen-containing pollutants can be converted into ammonia (NH3), an energy storage material. This method has the potential to address the high energy consumption and high carbon dioxide emissions associated with the traditional Haber-Bosch process for ammonia production. Furthermore, ammonia, a key raw material for fertilizers and chemical products, offers greater value-added benefits compared to nitrogen. The development of highly efficient electrocatalysts is central to this technology.

[0004] Copper (Cu)-based catalysts, due to their electronic orbital characteristics, easily form strong chemical bonds with nitrogen-containing pollutants and nitrogen intermediates, promoting their reduction. However, due to the strong covalent bond HO-H bond of H2O (about 492 kJ / mol), the surface of pure Cu catalyst dissociates H2O to produce active hydrogen ( Therefore, the balance between the adsorption strength of nitrogen-containing pollutants and nitrogen intermediates and the dissociation strength of H2O has a great influence on the yield and Faradaic efficiency of Cu-based electrocatalytic synthesis of NH3.

[0005] Studies have shown that the synthesis of Cu 0 / Cu 1+ The interface can provide Cu for Cu-based catalysts 0 -Cu 1+ Asymmetric site, Cu 0 With Cu 1 +The strong electronic interaction between Cu2O and Cu2O can effectively improve the adsorption strength of the material to nitrogen-containing pollutants and nitrogen intermediates and the H2O dissociation strength. Reference 1 provides a method to regulate the size effect of Cu2O. 0 -Cu 1+ Asymmetric dual-site approach for NO3 electrocatalysis - reaction, but due to Cu 1+ / Cu 0 The redox potential of Cu2O is 0.521V, so it is difficult to ensure that Cu2O can maintain Cu2O under reducing conditions. 0 -Cu 1+ Asymmetric double locus.

[0006] Reference 2 provides a C 60 A method for synthesizing ethylene glycol at normal pressure by using a buffered Cu / SiO2 catalyst, wherein C 60 / Cu / SiO2 material, using C 60 The electronic buffering effect of Cu 0 Electronic structures of species for thermocatalytic synthesis of ethylene glycol.

[0007] It can be seen that although a series of studies have been conducted in this field on copper-based catalysts for electrocatalytic synthesis of ammonia, the research cannot be said to be sufficient and there is still room for further exploration.

[0008] References:

[0009] Reference 1: Lu Y et al. Size-effect induced controllable Cu 0 -Cu + sites for ampere-level nitrate electroreduction coupled with biomass upgrading[J].Nature Communications, 2025, 16(1).DOI:10.1038 / s41467-025-57097-x.

[0010] Reference 2: Zheng J et al. Ambient-pressure synthesis of ethyleneglycol catalyzed by C 60 -buffered Cu / SiO2[J].Science, 2022, 376, 288-292. DOI:10.1126 / science.abm9257. Summary of the Invention

[0011] Problems to be solved by the invention

[0012] Based on the above problems, the present invention provides a method for preparing a dual-site Cu-based catalyst for electrocatalytic reduction of nitrogen-containing pollutants / N2O synthesis of ammonia, by introducing polymerized carbon into the Cu2O catalyst to form a Cu2O catalyst surface. 0 / Cu 1+ interface, providing Cu 0 -Cu 1+ Asymmetric sites while maintaining the Cu2O electrocatalyst's Cu through the electronic buffering effect of polymeric carbon 0 -Cu 1+ Asymmetric sites balance the adsorption strength of nitrogen-containing pollutants and nitrogen intermediates with the dissociation strength of H2O, and improve the performance of Cu-based catalysts in the electrocatalytic reduction of nitrogen-containing pollutants / N2O to synthesize NH3.

[0013] In addition, the present invention also provides a dual-site Cu-based catalyst prepared by the above method, wherein the dual-site Cu-based catalyst is a polymerized carbon-supported Cu2O catalyst.

[0014] Furthermore, the present invention also provides a method for electrocatalytic reduction of nitrogen-containing pollutants / N2O to synthesize ammonia, which improves its electrocatalytic performance by using an electrode loaded with the above-mentioned dual-site Cu-based catalyst as a working electrode.

[0015] Solutions for solving problems

[0016] The present invention first provides a method for preparing a dual-site Cu-based catalyst for electrocatalytic reduction of nitrogen-containing pollutants / N2O synthesis of ammonia, which comprises the following steps:

[0017] S1: dissolving polycarbon in an organic solvent to obtain a mixed solution A, impregnating a Cu2O catalyst in the mixed solution A to obtain a mixed solution B, and heating the mixed solution B to volatilize the organic solvent to obtain polycarbon / Cu2O powder; wherein the amount of the polycarbon is 1% to 10% by mass of the Cu2O catalyst;

[0018] S2: Grinding the polymerized carbon / Cu2O powder, annealing in an inert atmosphere, and cooling to obtain a polymerized carbon / Cu2O catalyst.

[0019] According to the preparation method of the present invention, the polymerized carbon comprises a carbon atom cluster having 20 to 100 carbon atoms; and / or,

[0020] The organic solvent includes one or more of benzene, toluene, cumene, bromoform, m-xylene, chlorobenzene, 1,2,3-tribromopropane, carbon disulfide, tetralin, 1,2,4-trichlorobenzene, 1,2-dichlorobenzene, 1-methylnaphthalene, and 1-chloronaphthalene; and / or,

[0021] The concentration of polymerized carbon in the mixed solution A is below 3.5 g / L.

[0022] According to the preparation method of the present invention, in step S1, the dissolution is performed by ultrasonic dissolution, and the ultrasonic dissolution time is 15 min to 60 min;

[0023] The immersion is carried out by ultrasonic immersion, and the time of the ultrasonic immersion is 15 minutes to 60 minutes;

[0024] The heating temperature is 50°C to 80°C.

[0025] According to the preparation method of the present invention, wherein, in step S2, the inert gas used in the inert atmosphere includes one or more of nitrogen, argon, and helium;

[0026] In the annealing step, the heating rate is 1-5°C / min, and the annealing temperature is 150-350°C.

[0027] According to the preparation method of the present invention, the preparation of the Cu2O catalyst comprises the following steps:

[0028] (1) dissolving a Cu precursor salt in ultrapure water to obtain a Cu precursor salt solution;

[0029] (2) Dissolve NaOH in ultrapure water to obtain a NaOH solution;

[0030] (3) Slowly add the NaOH solution to the Cu precursor salt solution and stir until the mixture is uniform. Then add D-(+)-glucose and heat it. Then filter, wash and dry it to obtain the Cu2O catalyst.

[0031] According to the preparation method of the present invention, the Cu precursor salt includes one or more of copper nitrate, copper nitrate trihydrate, copper sulfate, copper sulfate pentahydrate, copper chloride, copper chloride dihydrate, copper acetate or copper acetate monohydrate; and / or,

[0032] The resistivity of the ultrapure water is 18.2 MΩ cm; and / or,

[0033] The molar concentration of the Cu precursor salt solution is 0.03-0.1 mol / L; and / or,

[0034] The molar concentration of the NaOH solution is 0.5-2 mol / L; and / or,

[0035] The amount of ultrapure water in the NaOH solution is 0.5 to 0.7 times the amount of ultrapure water in the Cu precursor salt solution; and / or,

[0036] The amount of D-(+)-glucose added is 0.15-0.25 g for 1 mmol of Cu precursor salt; and / or,

[0037] The heating temperature is 50-70° C., and the heating time is 2-4 hours.

[0038] In addition, the present invention also provides a dual-site Cu-based catalyst prepared by the preparation method according to the present invention, wherein the dual-site Cu-based catalyst has Cu 0 -Cu 1+ Asymmetric sites.

[0039] Furthermore, the present invention also provides a method for electrocatalytic reduction of nitrogen-containing pollutants / N2O to synthesize ammonia, which comprises the following steps:

[0040] (I) mixing a second organic solvent, ultrapure water, a Nafion solution, and the polymerized carbon / Cu2O catalyst prepared according to the preparation method of the present invention, coating the mixture on the surface of carbon paper or carbon cloth, and drying the mixture to obtain a working electrode;

[0041] (II) The working electrode, the counter electrode, and the reference electrode are formed into a three-electrode system, which is inserted into an electrolyte solution to form an electrolytic cell, and nitrogen-containing pollutants and / or N2O are synthesized into ammonia by an electrocatalytic method.

[0042] According to the method of the present invention, the nitrogen-containing pollutants include one or more of nitrate, nitrite, nitric oxide, nitrogen dioxide or nitrous oxide.

[0043] According to the method of the present invention, wherein the second organic solvent comprises isopropanol or ethanol; and / or,

[0044] The density of the working electrode loaded with polymeric carbon / Cu2O catalyst is 0.5~1.5mg / cm 2 and / or,

[0045] The potential of the working electrode is 0~-1.2 vs. RHE.

[0046] Effects of the Invention

[0047] 1. The preparation method of the dual-site Cu-based catalyst provided by the present invention introduces polymerized carbon into the Cu2O catalyst. The electronic buffering effect of the polymerized carbon can transfer electrons to Cu2O, 1+ Reduction to Cu 0 , forming Cu 0 / Cu 1+ interface, providing Cu 0 -Cu 1+Asymmetric site. Under reducing conditions, Cu 1+ Will be reduced to Cu 0 , polymeric carbon can obtain electrons from Cu species, keeping a certain proportion of Cu 1+ sites, thereby maintaining the Cu 0 -Cu 1+ Asymmetric sites. Effectively improve the material's adsorption strength for nitrogen-containing pollutants and nitrogen intermediates, as well as its H2O dissociation strength, thereby increasing NH3 yield and Faradaic efficiency.

[0048] 2. The method for synthesizing ammonia by electrocatalytic reduction of nitrogen-containing pollutants / N2O provided by the present invention improves its electrocatalytic performance by using an electrode loaded with the dual-site Cu-based catalyst prepared by the present invention as a working electrode. This method has low energy consumption, high NH3 yield and Faraday efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 (a) shows the XRD test pattern of 5 wt% polymeric carbon / Cu2O catalyst in Example 2. Figure 1 (b) shows the XPS test graph of the 5 wt% polymeric carbon / Cu2O catalyst in Example 2;

[0050] Figure 2 The Cu2O catalyst of 5 wt% polymeric carbon / Cu2O in Example 2 under reducing conditions is shown. 1+ Proportion;

[0051] Figure 3 The NH3 yield and Faradaic efficiency of the electrocatalytic reduction of NO to NH3 over Cu2O and 5 wt% polymeric carbon / Cu2O catalysts in Example 4 at a working voltage of -1.1 V vs. RHE are shown;

[0052] Figure 4 The NH3 yield of 5 wt% polymeric carbon / Cu2O catalyst in Example 5 by electrocatalytic reduction of N2O to NH3 at a working voltage of -0.4 V vs. RHE is shown;

[0053] Figure 5 The electrocatalytic reduction of NO3 by Cu2O and 5 wt% polymeric carbon / Cu2O catalyst in Example 6 at a working voltage of -1.1 V vs. RHE is shown. - NH3 yield and Faradaic efficiency of synthetic NH3;

[0054] Figure 6 The electrocatalytic performance of Cu2O, 1wt% polymeric carbon / Cu2O, 5wt% polymeric carbon / Cu2O and 10wt% polymeric carbon / Cu2O catalysts in the H-type electrolytic cell for NO3 -LSV curve;

[0055] Figure 7 The electrocatalytic reduction of NO2 by Cu2O and 5 wt% polymeric carbon / Cu2O catalyst in Example 7 at a working voltage of -1.1 V vs. RHE is shown. - NH3 yield and Faradaic efficiency of synthetic NH3. DETAILED DESCRIPTION

[0056] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The word "exemplary" is used herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior or preferred over other embodiments.

[0057] In addition, numerous specific details are provided in the following detailed description to better illustrate the present invention. Those skilled in the art will appreciate that the present invention can be practiced without certain specific details. In other instances, methods, means, equipment, and steps well known to those skilled in the art are not described in detail in order to highlight the main points of the present invention.

[0058] Unless otherwise stated, the units used in this specification are international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0059] In this specification, the use of "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0060] References throughout this specification to "some specific / preferred embodiments," "other specific / preferred embodiments," "embodiments," etc., mean that the particular elements (e.g., features, structures, properties, and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein and may or may not be present in other embodiments. Furthermore, it should be understood that the elements may be combined in any suitable manner in various embodiments.

[0061] In this specification, a numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints A and B.

[0062] [First aspect]

[0063] A first aspect of the present invention provides a method for preparing a dual-site Cu-based catalyst for electrocatalytic reduction of nitrogen-containing pollutants / N2O synthesis of ammonia, comprising the following steps:

[0064] S1: dissolving polycarbon in an organic solvent to obtain a mixed solution A, impregnating a Cu2O catalyst in the mixed solution A to obtain a mixed solution B, and heating the mixed solution B to volatilize the organic solvent to obtain polycarbon / Cu2O powder; wherein the amount of the polycarbon is 1% to 10% by mass of the Cu2O catalyst;

[0065] S2: Grinding the polycarbon / Cu2O powder, annealing in an inert atmosphere, and cooling to obtain a polycarbon / Cu2O catalyst, wherein the polycarbon / Cu2O catalyst is a dual-site Cu-based catalyst.

[0066] (Step S1)

[0067] Step S1 of the present invention is to dissolve the polymerized carbon in an organic solvent to obtain a mixed solution A, immerse the Cu2O catalyst in the mixed solution A to obtain a mixed solution B, and heat the mixed solution B to volatilize the organic solvent to obtain the polymerized carbon / Cu2O powder; by combining the polymerized carbon with Cu2O, a Cu2O catalyst can be formed on the surface of the Cu2O. 0 / Cu 1+ interface, providing Cu 0 -Cu 1+ Asymmetric sites.

[0068] The polymerized carbon of the present invention refers to a carbon aggregate with a clear structure composed of multiple carbon atoms through chemical bonds. In some specific embodiments, the polymerized carbon includes carbon atom clusters with 20 to 100 carbon atoms. The polymerized carbon of the present invention can not only form Cu on the surface of the copper-based catalyst, but also form a carbon atom with a specific structure. 0 / Cu 1+ interface, providing Cu 0 -Cu 1+ Asymmetric sites can also maintain the Cu during the reduction of copper-based catalysts through their electronic buffering effect. 0 -Cu 1+ Asymmetric sites balance the adsorption strength of nitrogen-containing pollutants and nitrogen intermediates with the dissociation strength of H2O, and improve the performance of copper-based catalysts in the electrocatalytic reduction of nitrogen-containing pollutants / N2O to synthesize NH3.

[0069] The amount of the polymerized carbon is 1% to 10% of the mass of the Cu2O catalyst, for example, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, etc. When the amount of the polymerized carbon is 1% to 10% of the mass of the Cu2O catalyst, it is sufficient to provide Cu2O on the surface of the Cu2O catalyst. 0 -Cu 1+ The effects of asymmetric sites and maintenance of double sites are difficult to achieve when the dosage of polycarbon is less than 1%. When the dosage of polycarbon exceeds 10%, the dosage approaches saturation and the above effects cannot be further effectively improved.

[0070] In some specific embodiments, the organic solvent may include one or more of benzene, toluene, cumene, bromoform, m-xylene, chlorobenzene, 1,2,3-tribromopropane, carbon disulfide, tetralin, 1,2,4-trichlorobenzene, 1,2-dichlorobenzene, 1-methylnaphthalene, and 1-chloronaphthalene.

[0071] In some specific embodiments, the concentration of polycarbon in the mixed solution A is less than 3.5 g / L, for example, it can be 3 g / L, 2 g / L, 1 g / L, 0.5 g / L, 0.2 g / L, 0.1 g / L, etc.

[0072] In some specific embodiments, from the perspective of improving the solubility of polymerized carbon, the dissolution can be performed by ultrasonic dissolution, and the time of the ultrasonic dissolution can be 15 minutes to 60 minutes.

[0073] In some specific embodiments, in order to fully impregnate the Cu2O catalyst, the impregnation may be performed by ultrasonic impregnation, and the ultrasonic impregnation time may be 15 to 60 minutes.

[0074] In some specific embodiments, the heating temperature is 50° C. to 80° C., for example, 55° C., 60° C., 65° C., 70° C., 75° C., etc. There is no particular limitation on the heating method, and it can be selected as needed, such as water bath heating. In addition, preferably, in order to further improve the efficiency of volatilization of the organic solvent, the heating can be performed in a fume hood.

[0075] There is no particular limitation on the preparation method of the Cu2O catalyst of the present invention, and the catalyst may be prepared by a method commonly used in the art. In some preferred embodiments, the preparation of the Cu2O catalyst may include the following steps:

[0076] (1) dissolving a Cu precursor salt in ultrapure water to obtain a Cu precursor salt solution;

[0077] (2) Dissolve NaOH in ultrapure water to obtain a NaOH solution;

[0078] (3) Slowly add the NaOH solution to the Cu precursor salt solution and stir until the mixture is uniform. Then add D-(+)-glucose and heat it. Then filter, wash and dry it to obtain the Cu2O catalyst.

[0079] In some specific embodiments, the Cu precursor salt may include one or more of copper nitrate (Cu(NO3)2), copper nitrate trihydrate (Cu(NO3)2·3H2O), copper sulfate (CuSO4), copper sulfate pentahydrate (CuSO4·5H2O), copper chloride (CuCl2), copper chloride dihydrate (CuCl2·2H2O), copper acetate (Cu(CO2CH3)2) or copper acetate monohydrate (Cu(CO2CH3)2·H2O).

[0080] For the ultrapure water, it means that the resistivity at room temperature is 18.2MΩ cm of water.

[0081] In some specific embodiments, the molar concentration of the Cu precursor salt is 0.03~0.1mol / L, for example, it can be 0.05mol / L, 0.07mol / L, 0.09mol / L, etc. Preferably, in order to fully dissolve the Cu precursor salt, the Cu precursor salt solution can be stirred and mixed, and the stirring and mixing time can be 5~10min.

[0082] In some specific embodiments, the molar concentration of the NaOH solution is 0.5~2 mol / L, for example, it can be 0.8 mol / L, 1 mol / L, 1.2 mol / L, 1.5 mol / L, 1.8 mol / L, etc. Preferably, in order to fully dissolve the NaOH, the NaOH solution can be stirred and mixed, and the stirring and mixing time can be 5~10 min.

[0083] In some specific embodiments, the amount of ultrapure water in the NaOH solution is 0.5 to 0.7 times the amount of ultrapure water in the Cu precursor salt solution, for example, it can be 0.55 times, 0.6 times, 0.65 times, etc. Preferably, in order to fully mix the NaOH solution and the Cu precursor salt solution, the mixed solution can be stirred and mixed, and the stirring and mixing time can be 15 to 45 minutes.

[0084] In some specific embodiments, the amount of D-(+)-glucose added is 0.15-0.25 g per 1 mmol of Cu precursor salt.

[0085] In some specific embodiments, the heating and stirring temperature is 50-70°C, for example, 55°C, 60°C, 65°C, etc.; the heating and stirring time is 2-4h, for example, 2.5h, 3h, 3.5h, etc.

[0086] (Step S2)

[0087] Step S2 of the present invention is to grind the polycarbon / Cu2O powder, anneal it in an inert atmosphere, and cool it to obtain a polycarbon / Cu2O catalyst. The polycarbon / Cu2O catalyst is a dual-site Cu-based catalyst. Annealing in this step stabilizes the bond between the polycarbon and Cu2O.

[0088] In some specific embodiments, the inert gas used in the inert atmosphere may include one or more of nitrogen (N2), argon (Ar), and helium (He).

[0089] In some specific embodiments, during the annealing step, the heating rate is 1-5°C / min, for example, 2°C / min, 3°C / min, 4°C / min, etc.; the annealing temperature is 150-350°C, for example, 200°C, 250°C, 300°C, etc. Under these annealing conditions, the bonding strength between the polycarbonate and Cu2O can be effectively enhanced. When the annealing temperature is lower than 150°C, the above effect is difficult to achieve, and when the annealing temperature is higher than 350°C, the polycarbonate may decompose.

[0090] [Second aspect]

[0091] The second aspect of the present invention provides a dual-site Cu-based catalyst, which is a polymerized carbon-supported Cu2O catalyst, which is prepared by the preparation method described in the first aspect of the present invention, and the dual-site Cu-based catalyst has Cu 0 -Cu 1+ Asymmetric sites.

[0092] [Third aspect]

[0093] A third aspect of the present invention provides a method for electrocatalytic reduction of nitrogen-containing pollutants / N2O to synthesize ammonia, comprising the following steps:

[0094] (I) mixing a second organic solvent, ultrapure water, a Nafion solution, and the polymerized carbon / Cu2O catalyst prepared by the preparation method according to the first aspect of the present invention, coating the mixture on a surface of carbon paper or carbon cloth, and drying the mixture to obtain a working electrode;

[0095] (II) The working electrode, the counter electrode, and the reference electrode are formed into a three-electrode system, which is inserted into an electrolyte solution to form an electrolytic cell, and nitrogen-containing pollutants and / or N2O are synthesized into ammonia by an electrocatalytic method.

[0096] In some specific embodiments, the nitrogen-containing pollutants may include nitrates (NO3 - ), nitrite (NO2 - ), nitric oxide (NO) or nitrogen dioxide (NO2), etc.

[0097] In some specific embodiments, the second organic solvent can be isopropanol or ethanol, preferably isopropanol.

[0098] In some specific embodiments, the density of the working electrode loaded with the polymeric carbon / Cu2O catalyst is 0.5-1.5 mg / cm 2 , for example, it can be 0.8 mg / cm 2 , 1mg / cm 2 , 1.2mg / cm 2 , 1.4mg / cm 2 wait.

[0099] In some specific embodiments, the usage ratio of the second organic solvent, ultrapure water, Nafion (perfluorosulfonic acid polymer) solution and polymerized carbon / Cu2O catalyst is: (960~980)μL:(10~30)μL:(5~15)μL:(3~8)mg, preferably, the usage ratio is 970μL:20μL:10μL:5mg.

[0100] The present invention does not particularly limit the type of the counter electrode, and a counter electrode commonly used in the art, such as Pt, etc., can be used.

[0101] The present invention does not particularly limit the type of the reference electrode, and a reference electrode commonly used in the art may be used, for example, a reversible hydrogen reference electrode (RHE).

[0102] In some specific embodiments, the potential of the working electrode is 0 to -1.2 V vs. RHE, for example, -0.2 V vs. RHE, -0.5 V vs. RHE, -0.8 V vs. RHE, -1 V vs. RHE, -1.1 V vs. RHE, etc. Generally, when the voltage is lower than 0.521 V vs. RHE, Cu2O will be reduced to Cu 0 However, in the present invention, due to the electronic buffering effect of the polymerized carbon, there are still Cu on the catalyst surface at the above working voltage. 1+ .

[0103] The present invention has no particular limitation on the type of the electrolyte solution, and any electrolyte solution commonly used in the art may be used.

[0104] Example

[0105] The embodiments of the present invention will be described in detail below with reference to the examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present invention and should not be construed as limiting the scope of the invention. Where specific conditions are not specified in the examples, the methods were performed according to conventional conditions or the conditions recommended by the manufacturer. Where the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be obtained commercially.

[0106] Example 1

[0107] This example relates to the preparation of a 1 wt% polymerized carbon / Cu2O catalyst, and the specific operations are as follows:

[0108] (1) Select copper chloride dihydrate (CuCl2·2H2O) as the Cu precursor salt, weigh 1.534 g of CuCl2·2H2O and dissolve it in 150 mL of ultrapure water, stir for 10 min, and prepare liquid A.

[0109] (2) Weigh 7.2 g of NaOH and dissolve it in 90 mL of ultrapure water. Stir for 10 min to prepare solution B.

[0110] (3) Slowly add solution B to solution A and stir for 30 min. Then add 1.8 g of D-(+)-glucose and heat in a water bath at 60°C for 3 h. Then wash with water, filter, and wash to obtain the Cu2O catalyst. Dry in a vacuum at 60°C for 12 h for later use.

[0111] (4) Weigh 3 mg of polycarbonate C 60 , dissolved in 15 mL of toluene and sonicated for 30 minutes. Then, 300 mg of Cu2O catalyst was added and sonicated for 30 minutes. The mixture was then transferred to a beaker and heated in a water bath at 60°C with stirring until the organic solvent was completely evaporated, yielding a 1 wt% polymerized carbon / Cu2O powder.

[0112] (5) 1 wt% polycarbon / Cu2O powder was then ground and annealed at 200 °C at a heating rate of 2 °C / min in an Ar atmosphere for 2 h to prepare a 1 wt% polycarbon / Cu2O catalyst.

[0113] Example 2

[0114] This embodiment relates to the preparation of a 5wt% polymerized carbon / Cu2O catalyst. The difference between this embodiment and embodiment 1 is that the polymerized carbon C in step (4) of embodiment 1 is replaced by 60 The amount used was changed to 15 mg, and the remaining steps were the same as in Example 1 to obtain a 5 wt% polymerized carbon / Cu2O catalyst.

[0115] The XRD and XPS tests of 5wt% polycarbon / Cu2O catalyst were carried out. The XRD test results of 5wt% polycarbon / Cu2O catalyst are shown in the figure. Figure 1 As shown in (a), the XPS test results are as follows Figure 1 As shown in (b) in . Figure 1 As can be seen from (a) in the figure, after adding 5wt% polycarbon, the XRD test results show that the 5wt% polycarbon / Cu2O catalyst is a mixture of Cu2O and Cu. Figure 1 As can be seen from (b), XPS test further proves that the 5wt% polymeric carbon / Cu2O catalyst has both Cu 0 Site and Cu 1+ sites, and the XPS test results show that Cu 2+ This may be due to the surface oxidation of the catalyst during the test.

[0116] Cu in the electrocatalytic reduction process of 5wt% polymeric carbon / Cu2O catalyst 1+ Species such as Figure 2 Generally speaking, when the voltage is lower than 0.521 V vs. RHE, Cu2O will be reduced to Cu 0 ,Depend on Figure 2 It can be seen that even at a negative voltage of -0.8~-0.9 Vvs. RHE, Cu can still be detected on the surface of the 5wt% polycarbon / Cu2O catalyst. 1+ It can be seen that by adding polymeric carbon, the Cu2O catalyst can be maintained under reducing conditions. 0 -Cu 1+ Effects of asymmetric sites.

[0117] Example 3

[0118] This embodiment relates to the preparation of a 10 wt% polymerized carbon / Cu2O catalyst. The difference between this embodiment and embodiment 1 is that the polymerized carbon C in step (4) of embodiment 1 is replaced by 60 The amount used was changed to 30 mg, and the remaining steps were the same as in Example 1 to obtain a 10 wt% polymerized carbon / Cu2O catalyst.

[0119] Comparative Example 1

[0120] This comparative example relates to the preparation of a Cu2O catalyst, and the preparation method thereof is as shown in steps (1) to (3) in Example 1 to obtain a Cu2O catalyst.

[0121] Example 4

[0122] This embodiment relates to a method for synthesizing ammonia by electrocatalytic reduction of NO, and the specific operations are as follows:

[0123] (1) 5 mg of the 5 wt% polycarbon / Cu2O catalyst in Example 2 and 5 mg of Cu2O in Comparative Example 1 were weighed and mixed with 970 μL of isopropanol, 20 μL of ultrapure water, and 10 μL of Nafion solution to prepare ink solutions.

[0124] (2) Ultrasonicate the ink solution for 30 minutes to make it evenly dispersed. Apply it on carbon paper with a coating area of ​​1 1cm, coating amount is 0.5mg / cm 2 , and use this as the working electrode.

[0125] (3) The coated working electrode, the Pt sheet (counter electrode), and the reference electrode were combined into a three-electrode system and inserted into the electrolyte solution to form an electrolytic cell. The electrocatalytic reduction of NO to synthesize NH3 was carried out in the electrolytic cell at a potential of -1.1 V vs. RHE for 30 min.

[0126] The NH3 yield and Faradaic efficiency of Cu2O and 5wt% polycarbon / Cu2O catalysts for the electrocatalytic reduction of NO to NH3 at a working voltage of -1.1 V vs. RHE were tested. The specific test method was: 1% NO / Ar gas was introduced into the electrolyte solution at a flow rate of 10 mL / min for 30 minutes. Subsequently, 1% NO / Ar gas was introduced at a flow rate of 10 mL / min while conducting the experiment at a specified working voltage for 30 minutes. The NH3 concentration in the electrolyte solution after the experiment was measured by spectrophotometry. The results are shown in the figure. Figure 3 As shown. Figure 3 It can be seen that Cu2O has a high electrocatalytic activity of >1 mg h -1 mg cat -2 The 5wt% polymeric carbon / Cu2O catalyst significantly improved the electrocatalytic NOx performance (NH3 yield increased by more than 20% and Faradaic efficiency increased by more than 45%).

[0127] Example 5

[0128] This embodiment relates to a method for synthesizing ammonia by electrocatalytic reduction of N2O, and the specific operations are as follows:

[0129] (1) Weigh 5 mg of the 5 wt% polymeric carbon / Cu2O catalyst from Example 2 and prepare an Ink solution with 970 μL of isopropanol, 20 μL of ultrapure water, and 10 μL of Nafion solution.

[0130] (2) Ultrasonicate the ink solution for 30 minutes to make it evenly dispersed. Apply it on carbon paper with a coating area of ​​1 1cm, coating amount is 0.5mg / cm 2, and use this as the working electrode.

[0131] (3) The coated working electrode, the Pt sheet (counter electrode), and the reference electrode were combined into a three-electrode system and inserted into the electrolyte solution to form an electrolytic cell. The electrocatalytic reduction of NO to synthesize NH3 was carried out in the electrolytic cell at a potential of -0.4 V vs. RHE for 30 min.

[0132] The NH3 yield and Faradaic efficiency of 5wt% polycarbon / Cu2O catalyst for the electrocatalytic reduction of N2O to NH3 at a working voltage of -0.4 V vs. RHE were tested. The specific test method was: Ar gas at a flow rate of 10mL / min was introduced into the electrolyte solution for 30 minutes, followed by a 1% NO / Ar gas flow rate of 10mL / min while conducting the experiment at a specified working voltage for 6 hours. Figure 4 It can be seen that the electrocatalytic N2O synthesis ammonia yield of 5wt% polycarbon / Cu2O catalyst is 0.64 mg 6h -1 mg cat -2 .

[0133] Example 6

[0134] This embodiment relates to a method for electrocatalytic reduction of NO3 - The method for synthesizing ammonia is specifically performed as follows:

[0135] (1) 5 mg of the catalysts prepared in Examples 1 to 3 and Comparative Example 1 were weighed and mixed with 970 μL of isopropanol, 20 μL of ultrapure water, and 10 μL of Nafion solution to prepare ink solutions.

[0136] (2) The preparation of the working electrode is the same as that in Example 4, where the working electrode size is 0.5 0.5 cm, coating amount is 1 mg / cm 2 .

[0137] (3) The coated working electrode, Pt sheet (counter electrode), and reference electrode were combined into a three-electrode system, which was inserted into the electrolyte solution to form an electrolytic cell. The electrocatalytic reduction of NO3 was carried out in an H-type electrolytic cell at a potential of -1.1 V vs. RHE for 60 min. - Synthetic NH3 reaction.

[0138] Electrocatalytic reduction of NO3 by Cu2O and 5wt% polycarbon / Cu2O catalysts at -1.1 V vs. RHE - The NH3 yield and Faradaic efficiency of NH3 synthesis are shown in the following table: Figure 5 As shown. Figure 5 It can be seen that Cu2O electrocatalyzes NO3- >37 mg h -1 mg cat -2 The electrocatalytic NO3 conversion of 5wt% polymeric carbon / Cu2O catalyst was NH3 yield and 78% Faradaic efficiency. - The performance is greatly improved (NH3 production rate> 58 mg h -1 mg cat -2 , Faradaic efficiency>85%).

[0139] The electrocatalytic activity of Cu2O, 1wt% polycarbon / Cu2O, 5wt% polycarbon / Cu2O, and 10wt% polycarbon / Cu2O in the H-type electrolytic cell was tested over a voltage range of 0 to -1.2 V vs. RHE. - When the working current is drawn, the LSV curve is drawn, and the test results are as follows Figure 6 As shown. Figure 6 It can be seen that when using polymerized carbon C 60 After regulating the Cu2O double site, electrocatalysis of NO3 - The performance has been significantly improved.

[0140] Example 7

[0141] This embodiment relates to a method for electrocatalytic reduction of NO2 - The method for synthesizing ammonia is specifically performed as follows:

[0142] (1) The ink solution configuration and working electrode preparation are the same as those in Example 4, where the working electrode size is 0.5 0.5cm, coating amount is 1 mg / cm 2 .

[0143] (2) The coated working electrode, Pt sheet (counter electrode), and reference electrode were combined into a three-electrode system and inserted into the electrolyte solution to form an electrolytic cell. The electrocatalytic reduction of NO2 was carried out in an H-type electrolytic cell at a potential of -1.1 V vs. RHE for 60 min. - Synthetic NH3 reaction.

[0144] Electrocatalytic reduction of NO2 by Cu2O and 5wt% polycarbon / Cu2O catalysts at -1.1 V vs. RHE - The NH3 yield and Faradaic efficiency of NH3 synthesis are shown in the following table: Figure 7 As shown. Figure 7 It can be seen that Cu2O electrocatalyzes NO2 - >50mg h -1 mg cat -2The electrocatalytic NO2 - The performance is greatly improved (NH3 production rate>71.1 mg h -1 mg cat -2 , Faradaic efficiency>96%).

[0145] It should be noted that, although the technical solutions of the present invention are described with specific examples, those skilled in the art will appreciate that the present invention should not be limited thereto.

[0146] While various embodiments of the present invention have been described above, the above descriptions are intended to be illustrative, non-exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or technological improvements in the marketplace, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for preparing a dual-site Cu-based catalyst for electrocatalytic reduction of nitrogen-containing pollutants / N2O synthesis of ammonia, characterized in that: The following steps are involved: S1: dissolving polycarbon in an organic solvent to obtain a mixed solution A, impregnating a Cu2O catalyst in the mixed solution A to obtain a mixed solution B, and heating the mixed solution B to volatilize the organic solvent to obtain polycarbon / Cu2O powder; wherein the amount of the polycarbon is 1% to 10% by mass of the Cu2O catalyst; S2: Grinding the polymerized carbon / Cu2O powder, annealing in an inert atmosphere, and cooling to obtain a polymerized carbon / Cu2O catalyst.

2. The preparation method according to claim 1, characterized in that The polymerized carbon comprises a carbon atom cluster having 20 to 100 carbon atoms; and / or, The organic solvent includes one or more of benzene, toluene, cumene, bromoform, m-xylene, chlorobenzene, 1,2,3-tribromopropane, carbon disulfide, tetralin, 1,2,4-trichlorobenzene, 1,2-dichlorobenzene, 1-methylnaphthalene, and 1-chloronaphthalene; and / or, The concentration of polymerized carbon in the mixed solution A is below 3.5 g / L.

3. The preparation method according to claim 1 or 2, characterized in that In step S1, the dissolution is carried out by ultrasonic dissolution, and the ultrasonic dissolution time is 15 minutes to 60 minutes; The immersion is carried out by ultrasonic immersion, and the time of the ultrasonic immersion is 15 minutes to 60 minutes; The heating temperature is 50°C to 80°C.

4. The preparation method according to claim 1 or 2, characterized in that In step S2, the inert gas used in the inert atmosphere includes one or more of nitrogen, argon, and helium; In the annealing step, the heating rate is 1-5°C / min, and the annealing temperature is 150-350°C.

5. The preparation method according to claim 1 or 2, characterized in that The preparation of the Cu2O catalyst comprises the following steps: (1) dissolving a Cu precursor salt in ultrapure water to obtain a Cu precursor salt solution; (2) Dissolve NaOH in ultrapure water to obtain a NaOH solution; (3) Slowly add the NaOH solution to the Cu precursor salt solution and stir until the mixture is uniform. Then add D-(+)-glucose and heat it. Then filter, wash and dry it to obtain the Cu2O catalyst.

6. The preparation method according to claim 5, characterized in that The Cu precursor salt includes one or more of copper nitrate, copper nitrate trihydrate, copper sulfate, copper sulfate pentahydrate, copper chloride, copper chloride dihydrate, copper acetate or copper acetate monohydrate; and / or, The resistivity of the ultrapure water is 18.2 MΩ cm; and / or, The molar concentration of the Cu precursor salt solution is 0.03-0.1 mol / L; and / or, The molar concentration of the NaOH solution is 0.5-2 mol / L; and / or, The amount of ultrapure water in the NaOH solution is 0.5 to 0.7 times the amount of ultrapure water in the Cu precursor salt solution; and / or, The amount of D-(+)-glucose added is 0.15-0.25 g for 1 mmol of Cu precursor salt; and / or, The heating temperature is 50-70° C., and the heating time is 2-4 hours.

7. A dual-site Cu-based catalyst prepared by the preparation method according to any one of claims 1 to 6, wherein the dual-site Cu-based catalyst has Cu 0 -Cu 1+ Asymmetric sites.

8. A method for electrocatalytic reduction of nitrogen-containing pollutants / N2O to synthesize ammonia, characterized in that: The following steps are involved: (I) mixing a second organic solvent, ultrapure water, a Nafion solution, and a polymerized carbon / Cu2O catalyst prepared by the preparation method according to any one of claims 1 to 6, coating the mixture on a surface of carbon paper or carbon cloth, and drying the mixture to obtain a working electrode; (II) The working electrode, the counter electrode, and the reference electrode are formed into a three-electrode system, which is inserted into an electrolyte solution to form an electrolytic cell, and nitrogen-containing pollutants and / or N2O are synthesized into ammonia by an electrocatalytic method.

9. The method according to claim 8, characterized in that The nitrogen-containing pollutants include one or more of nitrate, nitrite, nitric oxide or nitrogen dioxide.

10. The method according to claim 8 or 9, characterized in that The second organic solvent comprises isopropanol or ethanol; and / or, The density of the working electrode loaded with polymeric carbon / Cu2O catalyst is 0.5~1.5mg / cm 2 and / or, The potential of the working electrode is 0~-1.2 vs. RHE.

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