Preparation method and application of a foamed copper loaded Co3CuN inverse perovskite material

Abstract

The application discloses a preparation method and application of a Co3CuN inverse perovskite material loaded on foamed copper. Cobalt nitrate hexahydrate is used as a cobalt source, foamed copper is used as a copper source and a substrate, and urea is used as an inducing agent to promote in-situ formation of Cu / Co hydroxide precursors; a one-step method is adopted for high-temperature nitriding and reduction, NH3 is generated by decomposition of urea at high temperature, and reduction and nitrogen doping of the metal material are realized. Meanwhile, the network structure of the foamed copper provides abundant sites for loading of the Co3CuN on the foamed copper. The Co3CuN grown in-situ on the foamed copper is structurally stable, effectively prevents metal ions from being precipitated, improves dispersivity of the material, and further improves catalytic activity of the material due to metal-nitrogen coupling in the inverse perovskite. The catalyst has high selectivity to generate singlet oxygen after being contacted with potassium peroxodisulfate, and can efficiently and rapidly remove new pollutants in water bodies due to high oxidizability and specificity of the singlet oxygen, and has potential to become a Fenton-like catalyst with excellent performance.

Description

Technical Field

[0001] This invention belongs to the field of environmental protection and water treatment technology, specifically relating to a method for preparing and applying a copper foam-supported Co3CuN anti-perovskite material. Background Technology

[0002] With the development of human industrial technology and the improvement of people's living standards, many emerging pollutants have quietly appeared and rapidly invaded every corner of human society. These emerging pollutants are referred to as new pollutants in my country, including persistent organic pollutants, endocrine disruptors, and antibiotics. The main source of new pollutants is the production and use of toxic and harmful chemicals. Their characteristics include insidious exposure, persistent retention, and difficulty in detecting harm to human health and the environment. Due to their low concentration but high toxicity, and complex and stable chemical structure, commonly used water treatment technologies, including physical, chemical, biological, and membrane separation methods, are ineffective in treating new pollutants. Advanced oxidation technologies, which degrade pollutants through the oxidation of highly reactive free radicals, are suitable for treating new pollutants that are difficult to remove using traditional methods. Fenton oxidation is a process that utilizes hydrogen peroxide (H₂O₂) and ferrous ions (Fe²⁺). 2 + This advanced oxidation technology generates hydroxyl radicals (·OH) to oxidize and degrade pollutants in water. The Fenton-like process is an advanced oxidation technology derived from the Fenton process. Compared to the Fenton process, the Fenton-like process uses different metal ions (such as Fe) to generate hydroxyl radicals (·OH), thereby oxidizing and degrading pollutants in water. 3+ Cu 2+ Mn 2+ Activating oxidants generate highly reactive free radicals (such as hydroxyl radicals ·OH) and non-free radicals (such as singlet oxygen radicals). 1 O2) is used to degrade recalcitrant pollutants in water.

[0003] In advanced oxidation technologies similar to the Fenton process, the use of heterogeneous catalysts to activate the oxidant is a common approach. Heterogeneous catalysts are those that exist in a solid phase and are in a different phase (e.g., solid-liquid or solid-gas) from the reactants. Common heterogeneous Fenton-type catalysts include iron-based oxides, composite oxides, iron-supported iron materials, molecular sieves, and metal-organic frameworks (MOFs). Furthermore, heterogeneous catalysts supported on stable materials have also been extensively studied. Compared to homogeneous catalysts (such as Fe dissolved in water), these heterogeneous catalysts offer advantages over homogeneous catalysts. 2+ or Fe 3+Heterogeneous catalysts offer advantages such as easy separation, recyclability, low residual metal pollution, and a wider operating range. These advantages make them applicable in solid, liquid, and gaseous processes. In water treatment, they are used to remove trace pollutants from drinking water and recalcitrant organic matter from wastewater, and are particularly suitable for the advanced treatment of high-concentration wastewater. In soil remediation, solid heterogeneous catalysts can be directly applied to soil remediation, utilizing soil moisture and H2O2 to achieve in-situ oxidative degradation. In air treatment systems, heterogeneous catalysts can be used in combination with ozone or H2O2 to degrade volatile organic compounds in the air. However, heterogeneous catalysts also have drawbacks: because they are solid, they cannot fully contact the solution, and their activity may be lower than that of homogeneous catalysts; after multiple cycles, the catalyst surface may be covered by contaminants or byproducts, leading to catalyst deactivation; heterogeneous catalysts often contain metals such as iron, copper, and manganese, which are easily leached under acidic or extreme conditions, causing secondary pollution, especially in Fenton-type catalysts, where the leaching of Fe ions can contaminate the effluent; the synthesis steps are complex and costly, and the preparation process of some heterogeneous catalysts requires precise control of temperature, pressure, atmosphere, and other conditions, which limits the large-scale production and application of catalysts; in dynamic water flow environments, catalyst particles may be lost with the water flow, which not only affects treatment efficiency but also increases particulate pollution in the water. Although heterogeneous catalysts have many advantages in the field of water treatment, their low catalytic activity, easy deactivation, metal leaching, and difficulty in regeneration limit their widespread application. To improve the application prospects of heterogeneous catalysts, it is necessary to develop more stable, easily recyclable and widely applicable heterogeneous catalysts, while exploring simpler regeneration methods and low-cost synthesis processes to overcome current shortcomings and limitations.

[0004] Anti-perovskites, derived from the electron inversion of perovskites, possess magnetic properties, superconductivity, negative thermal expansion, and the ability to act as host materials for photoluminescence. Furthermore, by adjusting the composition within the anti-perovskite lattice, the metal-nitrogen coupling can be fine-tuned, thereby altering magnetic properties, transport channels, and catalytic performance. The metal-nitride active centers of these anti-perovskites exhibit properties comparable to metal ions, thus endowing them with catalytic activity similar to metal ions while avoiding secondary pollution caused by metal ion precipitation during the reaction process. In recent years, various anti-perovskites such as Cu3N and Co4N have been synthesized, demonstrating good performance in pollutant degradation and representing promising new heterogeneous catalysts. However, the synthesis process of anti-perovskites is complex, and the recovery of powdered materials is difficult. For example, Cu3N requires continuous degassing of the solution in nitrogen at 105°C for 1 hour, followed by raising the temperature of the reaction mixture to 260°C and holding it for 5 minutes, then cooling it to 80°C, and finally centrifuging and drying the particles at 7000 rpm. Therefore, simplifying the synthesis process and enhancing recyclability are of paramount importance for expanding the application of anti-perovskites in advanced oxidation technologies. Summary of the Invention

[0005] To address the problems of poor stability, complex preparation process, and high cost of existing heterogeneous Fenton catalysts, this invention provides a method for preparing and applying a copper foam-supported Co3CuN anti-perovskite material. Using cobalt nitrate hexahydrate as the cobalt source, copper foam as the copper source and substrate, and urea as the inducer, the material is synthesized in a one-step hydrothermal process involving high-temperature nitridation and reduction. The preparation method is simple and low-cost. The copper foam-supported Co3CuN anti-perovskite material exhibits stable structure and promising application prospects.

[0006] To address the shortcomings of existing technologies, the technical solution adopted by this invention is as follows:

[0007] A method for preparing copper foam-supported Co3CuN anti-perovskite material is disclosed, which uses cobalt nitrate hexahydrate as cobalt source, copper foam as copper source and substrate, and urea as inducer to promote the in-situ formation of Cu / Co hydroxide precursor; then, a one-step high-temperature nitriding and reduction method is adopted, in which NH3 is generated by the decomposition of urea at high temperature to achieve simultaneous reduction of precursor and nitrogen doping to form copper foam-supported Co3CuN anti-perovskite material.

[0008] As an improvement, the above preparation method includes the following steps:

[0009] Step 1: Dissolve the metal salt and urea in pure water and stir thoroughly to obtain a mixed solution;

[0010] Step 2: Activate the copper foam.

[0011] Step 3: The mixed solution and the treated copper foam are transferred to a stainless steel high-pressure reactor lined with polytetrafluoroethylene for hydrothermal reaction to obtain Cu / Co hydroxide precursor.

[0012] Step 4: After washing the Cu / Co hydroxide precursor 2-3 times, vacuum dry it and then spread it evenly in a small ceramic boat A. Then, place the small ceramic boat A in a tube furnace, with a small ceramic boat B containing sufficient urea placed in front. Then, in a high temperature and N2 atmosphere, the urea decomposes into NH3, and the Cu / Co hydroxide precursor undergoes high-temperature nitridation and reduction under the action of NH3 to obtain copper foam supported anti-perovskite material.

[0013] A further improvement is that the metal salt mentioned in step 1 is Co(NO3)2·6H2O, and its concentration is 50mM-80mM; the concentration of urea is 267mM-533mM.

[0014] A further improvement is that in step 1, the concentration of Co(NO3)2·6H2O is 50mM and the concentration of urea is 267mM.

[0015] A further improvement is that the density of the copper foam in step 2 is 800-1500 g / m³. 3 The area is 6×10 -4 m 2 .

[0016] A further improvement is that the pretreatment in step 2 involves ultrasonically immersing the copper foam in acetone, 0.1 mol / L hydrochloric acid, and anhydrous ethanol for 5-10 minutes. Before changing the immersion liquid, the copper foam is removed and rinsed from top to bottom with ultrapure water. The washing process is repeated 3 times.

[0017] A further improvement is that in step 3, the hydrothermal reaction temperature is 100-150℃ and the hydrothermal reaction time is 5-8h.

[0018] A further improvement is that in step 4, the vacuum drying temperature is 50-70℃ and the vacuum drying time is 10-12h; the high-temperature nitriding temperature is 500-700℃ and the time is 2-5h.

[0019] The above-mentioned copper foam-supported Co3CuN anti-perovskite material is used in the degradation of new pollutants, namely tetracycline hydrochloride, sulfamethoxazole, or ciprofloxacin.

[0020] Beneficial effects:

[0021] This invention discloses a method for preparing and applying a copper-supported Co3CuN anti-perovskite material, which has the following advantages:

[0022] 1. This invention employs an in-situ generation method, specifically using cobalt nitrate hexahydrate as the cobalt source, copper foam as the copper source and substrate, and urea as the inducing agent. It utilizes a hydrothermal method, employing a one-step synthesis of high-temperature nitridation and reduction. The target catalyst can be synthesized in only two operations, simplifying the synthesis process. This overcomes the problems of common loading methods such as solvothermal and impregnation methods, which suffer from poor bonding between the substrate and catalyst, easily leading to catalyst loss and secondary pollution.

[0023] 2. This invention uses copper foam as both the copper source and substrate. The network structure of copper foam provides abundant sites for the in-situ generation of Co3CuN, stabilizing its structure, effectively preventing metal ion precipitation, and improving the dispersibility of the Co3CuN anti-perovskite material. The in-situ growth method fosters a strong chemical bond between the anti-perovskite catalyst and the copper foam substrate, increasing catalyst stability and reducing detachment issues during use. Furthermore, the presence of nitrogen in the anti-perovskite and the metal-nitrogen coupling enhance the catalyst's catalytic activity. Therefore, copper foam-supported Co3CuN anti-perovskite possesses both a stable material structure and high catalytic activity, overcoming the problems of poor stability, complex preparation processes, and high costs faced by heterogeneous Fenton metal catalysts. It represents a promising new type of heterogeneous catalyst.

[0024] 3. The presence of nitrogen in the anti-perovskite and the metal-nitrogen coupling in this invention synergistically improve the catalytic activity of the copper foam-supported Co3CuN anti-perovskite material. Attached Figure Description

[0025] Figure 1 XRD patterns of copper foam-supported Co3CuN anti-perovskite materials prepared at different high-temperature nitriding temperatures;

[0026] Figure 2 The graph shows the degradation rate of different pollutants using the copper foam-supported Co3CuN material prepared in Example 1.

[0027] Figure 3 The graph shows the degradation rate of sulfamethoxazole at a concentration of 20 mg / L using the copper foam Co3CuN prepared in Example 1 for cyclic degradation.

[0028] Figure 4 The graph shows the degradation rate of sulfamethoxazole at a concentration of 20 mg / L using the copper foam Co3CuN material prepared in Example 1 after 20 min of ultrasonic treatment. Detailed Implementation

[0029] The technical solutions of the present invention will be further described in detail below through embodiments. However, the content of the present invention is not limited thereto. The described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort without departing from the essence of the present invention are within the scope of protection of the present invention.

[0030] Unless otherwise specified, the methods in this embodiment are conventional methods, and the materials and reagents used are obtained commercially or prepared according to conventional methods unless otherwise specified.

[0031] Example 1

[0032] A method for preparing a copper-supported Co3CuN anti-perovskite material includes the following steps:

[0033] S1, solution mixing

[0034] Mix 50 mM Co(NO3)2·6H2O and 267 mM urea for 10 min to obtain a mixed solution;

[0035] S2, Copper Foam Activation Treatment

[0036] The purchased density is 1200g / m³ 3 Copper foam was cut into pieces of 2×3cm and then ultrasonically soaked in acetone, 0.1mol / L hydrochloric acid, and anhydrous ethanol for 10 minutes. When changing the soaking liquid, the copper foam was rinsed from top to bottom with ultrapure water. The washing process was repeated 3 times to obtain activated copper foam.

[0037] S3, hydrothermal reaction

[0038] The mixed solution and the treated copper foam were transferred to a stainless steel high-pressure reactor lined with polytetrafluoroethylene and kept at 120°C for 6 hours to obtain the Cu / Co hydroxide precursor.

[0039] S4, High-temperature nitriding

[0040] The Cu / Co hydroxide precursor was washed with ultrapure water, and the washing process was repeated three times. Then, it was vacuum dried at 60°C for 12 hours. The Cu / Co hydroxide precursor was then spread evenly and placed in a small ceramic boat A. The small ceramic boat A was placed in a tube furnace, and a small ceramic boat B containing sufficient urea was placed in front of it. In a N2 atmosphere at 550°C, the urea decomposed into NH3. The precursor underwent high-temperature nitriding and reduction under the action of NH3 to obtain the anti-perovskite Co3CuN material supported on copper foam, denoted as Co3CuN-550.

[0041] Example 2

[0042] Except for step 3, where the high-temperature nitriding temperature is changed to 800℃, the rest is the same as in Example 1, and the resulting catalyst is denoted as Co3CuN-800.

[0043] Figure 1 The XRD patterns of the materials prepared in Examples 1-2 are shown in the figures. It can be seen from the figures that all the diffraction peaks of the product Co3CuN-550 in Example 1 and the product Co3CuN-800 in Example 2 are in complete agreement with the typical Co and Cu cards, which indicates that Co3CuN was successfully synthesized.

[0044] Example 3

[0045] Experimental tests on the degradation of new pollutants by the material prepared in Example 1:

[0046] A 100 mL solution of 20 mg / L tetracycline hydrochloride, sulfamethoxazole, and ciprofloxacin was prepared and adjusted to neutral using dilute sulfuric acid and sodium hydroxide solution. The prepared catalyst (2×3 cm) was added to the solution and mechanically stirred. Then, potassium persulfate was added to bring the concentration of potassium persulfate in the system to 0.65 mM. The temperature was set at 25 °C, and the change in pollutant concentration over time after the addition of potassium persulfate was measured.

[0047] The effect of copper foam-supported Co3CuN anti-perovskite material on the degradation of various pollutants, the results are as follows: Figure 2 Copper-supported anti-perovskite exhibits good degradation performance for tetracycline hydrochloride, sulfamethoxazole, and ciprofloxacin, with degradation rates of 100%, 100%, and 89% for tetracycline hydrochloride, sulfamethoxazole, and ciprofloxacin, respectively, within 600 s.

[0048] Example 4

[0049] Cyclic catalytic experiments were conducted on the material prepared in Example 1.

[0050] A 20 mg / L sulfamethoxazole solution (100 mL) was prepared and adjusted to neutral using dilute sulfuric acid and sodium hydroxide solution. A 2×3 cm sample of the prepared catalyst was added to the solution and mechanically stirred. Then, potassium persulfate was added to bring the concentration of potassium persulfate in the system to 0.65 mM. The temperature was set at 25 °C, and the reaction time was 10 min. After the reaction, the catalyst sample was removed from the solution and rinsed three times from top to bottom with anhydrous ethanol and pure water, respectively. A fresh 100 mL deionized water solution was prepared, and the washed catalyst was added to the solution. The mixture was mechanically stirred, and then potassium persulfate was added to bring the concentration of potassium persulfate in the system to 0.65 mM. The temperature was set at 25 °C, and the reaction time was 10 min. This process was repeated four times.

[0051] Depend on Figure 3 It can be seen that the copper-supported Co3CuN anti-perovskite provided by this invention degrades sulfamethoxazole by activating potassium persulfate. The first cycle achieves 100% degradation within 10 minutes, and maintains a 100% degradation rate after 5 cycles. This demonstrates that the copper-supported Co3CuN anti-perovskite prepared by this invention has good cycling performance.

[0052] Example 5

[0053] Stability tests were conducted on the material prepared in Example 1:

[0054] A 20 mg / L sulfamethoxazole solution (100 mL) was prepared and adjusted to neutral using dilute sulfuric acid and sodium hydroxide solution. A 2×3 cm sample of the prepared catalyst was first sonicated for 20 min, then added to the solution with mechanical stirring. Potassium persulfate was then added to bring the concentration of potassium persulfate in the system to 0.65 mM. The temperature was set at 25 °C, and the change in pollutant concentration over time after the addition of potassium persulfate was measured.

[0055] The effect of copper foam-supported anti-perovskite on pollutant degradation, results are as follows: Figure 4 As shown, the degradation performance of copper foam-supported anti-perovskite against sulfamethoxazole can still reach 100% within 10 minutes. This proves that the structure of copper foam-supported Co3CuN anti-perovskite is stable.

[0056] In summary, the copper foam-supported anti-perovskite material prepared by this invention has a simple preparation method, low cost, and features both high catalytic activity and high stability, thus it has the potential to become a Fenton-like catalyst.

[0057] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A method for preparing a Co3CuN inverse perovskite material loaded on a foamed copper, characterized in that, The method comprises the following steps: Step 1, dissolving the metal salt and urea in pure water and stirring to obtain a mixed solution; Step 2, activating the foamed copper; Step 3, transferring the mixed solution and the activated foamed copper into a stainless steel high-pressure reaction kettle with a polytetrafluoroethylene liner to perform a hydrothermal reaction to obtain a Cu / Co hydroxide precursor; Step 4, washing the Cu / Co hydroxide precursor for 2-3 times, vacuum drying, placing in a small porcelain boat A and evenly laying, then placing the small porcelain boat A in a tube furnace, preloading a small porcelain boat B with sufficient urea, then decomposing the urea into NH3 under a high temperature and N2 atmosphere, and performing high-temperature nitridation and reduction of the Cu / Co hydroxide precursor under the action of NH3 to obtain a foamed copper loaded Co3CuN inverse perovskite material.

2. The method according to claim 1, wherein the method is characterized by, The metal salt in step 1 is cobalt nitrate hexahydrate Co(NO3)2·6H2O with a concentration of 50 mM-80 mM; and the concentration of urea is 267 mM-533 mM.

3. The method according to claim 2, wherein the method is characterized by, In step 1, the concentration of Co(NO3)2·6H2O is 50 mM, and the concentration of urea is 267 mM.

4. The method according to claim 1, wherein the method is characterized by, The density of the foamed copper in step 2 is 800-1500 g / m 3 , and the area is 6 x 10 -4 m 2 .

5. The method according to claim 1, wherein the method is characterized by, In step 2, the activation treatment is ultrasonic immersion treatment of the foamed copper using acetone, 0.1 mol / L hydrochloric acid and anhydrous ethanol, respectively, and the ultrasonic time is 5-10 min; the foamed copper is taken out before replacing the immersion liquid, and the foamed copper is washed from top to bottom with ultrapure water, and the washing process is repeated for 3 times.

6. The method according to claim 1, wherein the method is characterized by, In step 3, the hydrothermal reaction temperature is 100-150 DEG C, and the hydrothermal reaction time is 5-8 h.

7. The method according to claim 1, wherein the method is characterized by, The temperature for vacuum drying in Step 4 is 50-70 o C, and the vacuum drying time is 10-12 h; the temperature for high-temperature nitriding is 500-700 o C, and the time is 2-5 h.

8. Use of the foam copper supported Co3CuN inverse perovskite material prepared according to the preparation method of any one of claims 1-7 for degrading emerging pollutants, characterized in that, The new pollutants are tetracycline hydrochloride, sulfamethoxazole or ciprofloxacin.

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