Preparation method and application of P-Cu / Fe2O3 bimetallic composite material

Abstract

The invention relates to a preparation method and application of a P-Cu / Fe2O3 bimetallic composite material, and belongs to the technical field of material preparation. The method comprises the following steps: synthesizing a phosphorus-doped double-metal hydroxide precursor by adopting a hydrothermal method, and finally calcining in an H2 atmosphere to obtain the P-Cu / Fe2O3 double-metal composite material. A P-Cu / Fe2O3 material is used as an electrocatalyst, and CO2 and NO3 <-> can be efficiently electrocatalytically reacted to selectively prepare urea. Compared with the prior art, the catalyst has the advantages of high catalytic activity, simple preparation, easily available raw materials, high activity and the like, and has important industrial application prospects in the aspect of synthesizing urea through electrocatalysis of CO2 and NO3 <->.

Description

Technical Field

[0001] The present invention belongs to the field of catalyst preparation, and specifically relates to a preparation method of a P-Cu / Fe2O3 bimetallic composite material and its application, and in particular to a preparation method of a P-Cu / Fe2O3 bimetallic composite material and its application in electrocatalysis of CO2 and NO3 - Application in the synthesis of urea. Background Art

[0002] Urea, as an organic chemical with a nitrogen content of up to 46%, is widely used in the fields of chemicals, dyes, fertilizers, etc., and is of great significance to the development of global agriculture and society. At present, the industrial production of urea mainly relies on the Haber-Bosch process, which is carried out under harsh conditions (150-200°C and 150-250bar) through the reaction between ammonia and carbon dioxide. It has high energy consumption and is accompanied by a large amount of CO2 emissions, exacerbating the problem of global warming. With the society's emphasis on the concept of sustainable development, the development of a clean urea production technology under mild conditions has become a development trend of future industrial production. At room temperature and atmospheric environment, CO2 and NO3 are converted into - Urea synthesis is a technology that is in line with the concept of sustainable development. Electrocatalytic urea synthesis is a series reaction, which firstly reduces NO3 to nitrate and then to carbon dioxide. - Reduction to *NO intermediate, CO2 reduction to *CO intermediate. Both steps involve the transfer of electrons and the coupling of protons, and are important reaction processes in the urea synthesis pathway.

[0003] Currently, research in electrocatalytic urea synthesis focuses primarily on the development of novel catalysts to improve the selectivity and efficiency of urea synthesis. While some breakthroughs have been achieved, issues such as insufficient activity, low selectivity, and poor stability persist in the electrocatalytic urea synthesis process. Therefore, developing electrocatalysts with high activity, selectivity, and stability is crucial for the practical application of electrocatalytic urea synthesis technology. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method and application of a P-Cu / Fe2O3 bimetallic composite material, wherein the method is a simple hydrothermal and calcination method to prepare the P-Cu / Fe2O3 bimetallic composite material. The catalyst electrocatalyzes CO2 and NO3 - The coupled reaction can achieve efficient electrosynthesis of urea.

[0005] Another object of the present invention is to provide a P-Cu / Fe2O3 bimetallic composite material and its application.

[0006] The specific technical solution for achieving the purpose of the present invention is: using different copper salts and iron salts as raw materials, obtaining a precursor through a hydrothermal reaction, and then calcining to obtain a P-Cu / Fe2O3 bimetallic composite material, including the following steps:

[0007] Step 1: Dissolve 4 mmol of copper salt and 2 mmol of iron salt in 10 mL of deionized water and stir for 1 hour to completely dissolve. Add 15 mmol of sodium phosphate to the above solution, then add deionized water to 50 mL and continue stirring for 24 hours.

[0008] Step 2: The resulting solution was transferred to a 100 mL stainless steel autoclave and subjected to a hydrothermal reaction at 160°C. After the reaction, the precipitate was separated by centrifugation, washed five times with deionized water and ethanol, and dried at 60°C for 24 hours to obtain a powder.

[0009] Step 3: The powder obtained in the above step 2 is subjected to high-temperature calcination treatment under H2 atmosphere to obtain the final P-Cu / Fe2O3 catalyst.

[0010] Furthermore, in the preparation method of the P-Cu / Fe2O3 bimetallic composite material, the copper salt and iron salt solution in step 1 can be any one of acetate, nitrate, and sulfate.

[0011] Furthermore, in the preparation method of the P-Cu / Fe2O3 bimetallic composite material, the hydrothermal reaction time in step 2 is 8 hours.

[0012] Furthermore, in the preparation method of the P-Cu / Fe2O3 bimetallic composite material, in the third step, the temperature is raised to 300°C at a heating rate of 3°C / min under H2 atmosphere and then reacted for 2 hours.

[0013] The P-Cu / Fe2O3 bimetallic composite material was prepared according to the above preparation method.

[0014] The present invention also provides a P-Cu / Fe2O3 bimetallic composite material as a catalyst for electrocatalysis of CO2 and NO3 - Application in the synthesis of urea.

[0015] One of the purposes of the present invention is to provide a method according to the present invention to prepare the P-Cu / Fe2O3 bimetallic composite material in the field of electrocatalysis, especially in the electrocatalysis of CO2 and NO3 - Application in the synthesis of urea.

[0016] The advantages of the preparation method of the P-Cu / Fe2O3 bimetallic composite material provided by the present invention are:

[0017] The present invention proposes a new method for preparing P-Cu / Fe2O3 bimetallic composite materials. The method uses a mixed solution of copper salt and iron salt, which is widely available and cost-effective, as the starting material, and is simple and efficient.

[0018] The obtained P-Cu / Fe2O3 bimetallic composite material exhibits excellent electrocatalytic performance in the preparation of urea, and these properties give it particularly outstanding advantages in the field of electrosynthesis applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a SEM image of the P-Cu / Fe2O3 bimetallic composite material prepared in Example 1;

[0020] Figure 2 is the X-ray diffraction (XRD) pattern of the P-Cu / Fe2O3 bimetallic composite material prepared in Example 1;

[0021] Figure 3 The P-Cu / Fe2O3 bimetallic composite material prepared in Example 1 electrocatalyzes CO2 and NO3 - Performance diagram of synthetic urea. DETAILED DESCRIPTION

[0022] The technical solutions of the present invention are further described in detail below with reference to the accompanying drawings and specific embodiments, but the present invention is not limited to the following embodiments.

[0023] Example 1

[0024] Dissolve 4 mmol of copper acetate and 2 mmol of ferric acetate in 10 mL of deionized water and stir for 1 hour to completely dissolve them. Add 15 mmol of sodium phosphate to the above solution, then add deionized water to 50 mL and continue stirring for 24 hours. Transfer the obtained solution to a 100 mL stainless steel high-pressure reactor and carry out a hydrothermal reaction at 160 ° C. After the reaction is completed, the precipitate is separated by centrifugation, washed with deionized water and ethanol 5 times, and dried at 60 ° C for 24 hours to obtain a powder. The powder obtained in the above steps is heated to 300 ° C at a heating rate of 3 ° C / min under H2 atmosphere and reacted for 2 hours to obtain the final P-Cu / Fe2O3 bimetallic composite material.

[0025] Figure 1 The SEM image of the P-Cu / Fe2O3 bimetallic composite material obtained in Example 1 is shown in FIG. Figure 1 It can be seen that the P-Cu / Fe2O3 bimetallic composite material presents a porous structure formed by stacking nanoparticles, and the size of these nanoparticles is about 50 nanometers. Figure 2This is the XRD pattern of the P-Cu / Fe2O3 bimetallic composite material obtained in Example 1. The crystal structure of the catalyst was analyzed from the pattern, and the phases of Cu and Fe2O3 were confirmed.

[0026] Example 2

[0027] Dissolve 4mmol of copper nitrate and 2mmol of ferric nitrate in 10mL of deionized water and stir for 1 hour to completely dissolve them. Add 15mmol of sodium phosphate to the above solution, then add deionized water to 50mL and continue stirring for 24 hours. Transfer the obtained solution to a 100mL stainless steel high-pressure reactor and carry out hydrothermal reaction at 160°C. After the reaction is completed, the precipitate is separated by centrifugation, washed with deionized water and ethanol 5 times, and dried at 60°C for 24 hours to obtain powder. The powder obtained in the above steps is heated to 300°C at a heating rate of 3°C / min under H2 atmosphere and reacted for 2 hours to obtain the final P-Cu / Fe2O3 bimetallic composite material.

[0028] Example 3

[0029] Dissolve 4 mmol of copper sulfate and 2 mmol of iron sulfate in 10 mL of deionized water and stir for 1 hour to completely dissolve them. Add 15 mmol of sodium phosphate to the above solution, then add deionized water to 50 mL and continue stirring for 24 hours. Transfer the obtained solution to a 100 mL stainless steel high-pressure reactor and carry out a hydrothermal reaction at 160 ° C. After the reaction is completed, the precipitate is separated by centrifugation, washed with deionized water and ethanol 5 times, and dried at 60 ° C for 24 hours to obtain a powder. The powder obtained in the above steps is heated to 300 ° C at a heating rate of 3 ° C / min under H2 atmosphere and reacted for 2 hours to obtain the final P-Cu / Fe2O3 bimetallic composite material.

[0030] Example 4

[0031] The corresponding electrochemical test experiments were all completed on a Shanghai Chenhua electrochemical workstation (CHI 6081E). The electrolysis test was carried out in an H-type electrolytic cell using a three-electrode system, including a working electrode (P-Cu / Fe2O3 bimetallic composite material), a Pt electrode as a counter electrode, and Ag / AgCl as a reference electrode. During the electrolysis process, the cathode / anode chambers were separated by a proton exchange membrane, and the electrolytes in the cathode chamber and the anode chamber were 0.1M KNO3 and 0.1M K2SO4, respectively. In constant potential mode, electrolysis was performed for 1 hour at each potential, and gas and liquid products were collected.

[0032] The components of the obtained product were detected and quantitatively analyzed by gas chromatography (Agilent 8890), nuclear magnetic resonance spectrometer (1H NMR, Bruker Ascend 500MHz) and diacetyl monoxime method. Figure 3 As shown in Figure 2, the Faradaic efficiency of urea produced by the P-Cu / Fe2O3 bimetallic composite at an electrolysis potential of -0.68 V vs. RHE is 73.81%, and the production rate is 62.74 mmol h -1 g -1 cat. .

[0033] Applicants hereby declare that the detailed description of the specific embodiments of the present invention is provided above for illustrative purposes only and is not intended to limit the scope of the present invention. Technical experts in the field will recognize that any equivalent modifications or alternatives to the present invention are within the scope of protection of the present invention. Therefore, all equivalent modifications and adaptive adjustments implemented without departing from the basic concept and scope of protection of the present invention are encompassed by the present invention.

Claims

1. A method for preparing a P-Cu / Fe2O3 bimetallic composite material, characterized in that: Firstly, a precursor is obtained through a hydrothermal reaction, and then a calcination treatment is performed to obtain a P-Cu / Fe2O3 bimetallic composite material.

2. The method for preparing a P-Cu / Fe2O3 bimetallic composite material according to claim 1, characterized in that: The specific steps include: Step 1: Dissolve 4 mmol of copper salt and 2 mmol of iron salt in 10 mL of deionized water and stir for 1 hour to completely dissolve them; add 15 mmol of sodium phosphate to the above solution, add deionized water to 50 mL, and continue stirring for 24 hours; Step 2: The obtained solution was transferred to a 100 mL stainless steel autoclave and subjected to a hydrothermal reaction at 160° C. After the reaction, the precipitate was separated by centrifugation, washed with deionized water and ethanol for 5 times, and dried at 60° C. for 24 hours to obtain a powder; Step 3: The powder obtained in the above step 2 is subjected to high-temperature calcination treatment under H2 atmosphere to obtain the final P-Cu / Fe2O3 bimetallic composite material.

3. The method for preparing the P-Cu / Fe2O3 bimetallic composite material according to claim 2, characterized in that: The copper salt and iron salt in step 1 may be any one of acetate, nitrate and sulfate.

4. The method for preparing the P-Cu / Fe2O3 bimetallic composite material according to claim 2, characterized in that: The hydrothermal reaction time in step 2 is 8 hours.

5. The method for preparing the P-Cu / Fe2O3 bimetallic composite material according to claim 2, characterized in that: In the step 3, the temperature is raised to 300° C. at a heating rate of 3° C. / min under a H 2 atmosphere and then reacted for 2 hours.

6. The P-Cu / Fe2O3 bimetallic composite material is prepared by the preparation method according to any one of claims 1 to 5.

7. The P-Cu / Fe2O3 bimetallic composite material as claimed in claim 6 is used as a catalyst in the electrocatalysis of CO2 and NO3 - Application in the synthesis of urea.

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