Copper oxide nanowire supported silver monatomic catalyst, preparation method and application
By loading silver single atoms onto copper oxide nanowires to form Ag@CuONWs array materials, the problems of poor activity and stability of copper-based catalysts were solved, achieving efficient reduction of 4-nitrophenol to 4-aminophenol and providing a new electrocatalytic method.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING UNIV OF CHEM TECH
- Filing Date
- 2024-03-05
- Publication Date
- 2026-07-24
AI Technical Summary
Existing copper-based catalysts exhibit poor activity, instability, and low selectivity during the reduction of nitrophenol, making it difficult to effectively reduce 4-nitrophenol to 4-aminophenol.
Silver single-atom catalysts were supported on copper oxide nanowires, and silver single atoms were grown in situ on the surface of copper oxide nanowires through electrochemical oxidation and chemical deposition to form Ag@CuONWs array materials, which provide high specific surface area and abundant active sites, and synergistically promote the reduction of 4-nitrophenol.
This improved the Faraday efficiency and stability of the catalyst, enabling efficient reduction of 4-nitrophenol to 4-aminophenol at low potentials, reducing production costs and providing a new method for the electrocatalytic reduction of nitrophenol.
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Figure CN118122340B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the fields of new energy nanomaterial synthesis and electrocatalysis technology, and in particular to a silver single-atom catalyst supported on copper oxide nanowires, its preparation method and application. Background Technology
[0002] With the rapid development of the chemical industry, environmental problems caused by organic pollution have become increasingly serious. 4-Nitrophenol (4-NP) was once classified as a toxic substance. Also known as p-nitrophenol, 4-NP is a common organic pollutant widely found in industrial and agricultural wastewater, causing significant harm to water bodies, soil, and plants and animals. Ingestion of 4-NP by animals can lead to organ failure, including liver and kidney failure, and in severe cases, death.
[0003] 4-Aminophenol (4-AP) is a common industrial chemical intermediate with wide applications in the synthesis of dyes, pharmaceuticals, and pesticides. Therefore, the electrocatalytic reduction of 4-NP to 4-AP is currently one of the technologies with significant economic and environmental benefits, effectively reducing environmental pollution and efficiently treating wastewater.
[0004] Copper-based catalysts are widely used in reactions such as nitrate reduction, nitrite reduction, and reduction of nitro-based organic compounds due to their unique electronic structure. Furthermore, copper oxide nanowire arrays possess a large specific surface area, enabling them to better adsorb intermediates from nitrophenol reduction, thus making them a popular choice as end-stage catalysts for nitro-based reductions.
[0005] In existing technologies, copper-based catalysts suffer from problems such as poor activity, poor stability, and low selectivity. Therefore, researching and preparing copper-based catalysts with high specific surface area and multiple active sites has become a research hotspot. Summary of the Invention
[0006] The purpose of this invention is to provide a silver single-atom catalyst supported on copper oxide nanowires, its preparation method, and its application. Copper oxide nanowires have advantages such as a large specific surface area and abundant active sites. Modifying copper oxide nanowires with silver single atoms can synergistically promote the reduction of 4-nitrophenol and improve the Faraday efficiency and stability of the catalyst.
[0007] To achieve the above objectives, the present invention provides a copper oxide nanowire-supported silver single-atom catalyst, comprising a substrate, CuO nanowires, and metal Ag single atoms supported on a CuO nanowire electrode layer;
[0008] The substrate is commercially available copper foam, which serves as a copper source for preparing array materials loaded with single Ag atoms on CuO nanowires.
[0009] To achieve the above objectives, the present invention also provides a method for preparing a silver single-atom catalyst supported on copper oxide nanowires, comprising the following steps:
[0010] S1. Pretreatment of copper foam substrate;
[0011] S2. CuO nanowires were obtained by in-situ growth on a copper foam substrate using an electrochemical oxidation method.
[0012] S3. Ag@CuONWs array material was obtained by in-situ growth of single Ag atoms on the surface of CuO nanowires using chemical deposition.
[0013] Preferably, in step S1, the pretreatment process specifically involves: sequentially cleaning the foamed copper with 1 mol / L hydrochloric acid, deionized water, and anhydrous ethanol, then removing and drying it to obtain foamed copper without grease or oxide layer on the surface.
[0014] Preferably, in step S2, the electrochemical oxidation method specifically includes:
[0015] S21. Preparation of Cu(OH)2NWs array material: Electrochemical oxidation was carried out using a three-electrode system and an H-type electrolytic cell, with a platinum sheet as the counter electrode, copper foam as the working electrode, and Ag / AgCl as the reference electrode, and Cu(OH)2NWs array material was obtained on the surface of copper foam.
[0016] S22. Preparation of CuO nanowire material: The Cu(OH)2NW array material obtained in step S21 is washed with deionized water and anhydrous ethanol in sequence, dried and annealed to obtain CuO nanowire material.
[0017] Preferably, in step S21, the electrolyte is a 1-3M potassium hydroxide solution, and the constant current is 40 mA / cm². -2 The oxidation time is 2400s.
[0018] Preferably, in step S22, an annealing process is performed using a muffle furnace with a heating rate of 5°C / min, heating to 350°C, and holding at that temperature for 120 min.
[0019] Preferably, in step S3, the chemical deposition method specifically includes:
[0020] Silver chloride and acetonitrile were mixed in proportion to prepare an AgCl-acetonitrile solution. Using the AgCl-acetonitrile solution as the electrolyte, electrochemical deposition was performed on the surface of CuO nanowires. The nanowires were then removed, allowed to stand, and washed with deionized water and anhydrous ethanol, respectively. After drying, Ag@CuONWs array materials with no silver chloride or acetonitrile on the surface were obtained.
[0021] Preferably, the concentration of the AgCl acetonitrile solution is 5–20 mM, and the deposition time is 0.5–1 h.
[0022] To achieve the above objectives, the present invention also provides an application of a silver single-atom catalyst supported on copper oxide nanowires, wherein the silver single-atom catalyst supported on copper oxide nanowires is used for the electrocatalytic reduction reaction of p-nitrophenol.
[0023] Preferably, the electrocatalysis specifically comprises:
[0024] An H-type electrolytic cell was used, with Ag@CuONWs array material as the working electrode, platinum sheet as the counter electrode, and Ag / AgCl electrode as the reference electrode. p-Nitrophenol was added to the electrolyte in a certain proportion.
[0025] The electrolyte is a carbonate solution, which is either potassium carbonate or potassium bicarbonate solution, and the concentration of the carbonate solution is 1M to 2M.
[0026] The concentration of p-nitrophenol is 10 mM.
[0027] Therefore, the present invention, employing the above-mentioned copper oxide nanowire-supported silver single-atom catalyst, preparation method, and application, has the following technical effects:
[0028] (1) This invention can synthesize a relatively stable copper oxide array structure catalyst by controlling different electrolysis currents and times. The selected foamed copper substrate is inexpensive, which reduces the production cost. The resulting catalyst has higher use value and performance, and has the advantages of low raw material cost, simple process and strong repeatability.
[0029] (2) Using copper oxide nanowires as templates, this invention obtained a three-dimensional array structure of copper nanowires loaded with silver single-atom catalytic material, providing a method for the synergistic promotion of nitro reduction by copper nanowires and silver single atoms, and as a highly efficient electrocatalyst for the reduction of nitrophenol, it provides a new idea for the future application of single atoms in the field of electrocatalytic reduction of nitrophenol. Attached Figure Description
[0030] Figure 1 This is an X-ray powder diffraction pattern of Ag@CuONWs array material prepared by copper oxide nanowire-supported silver single-atom catalyst, preparation method and application example 1 of this invention;
[0031] Figure 2 This is a scanning electron microscope image of the Ag@CuONWs array material prepared by the present invention, which is a copper oxide nanowire-supported silver single-atom catalyst, preparation method and application example 1.
[0032] Figure 3 This is a transmission electron microscope image of the Ag@CuONWs array material prepared by the present invention, which is a copper oxide nanowire-supported silver single-atom catalyst, preparation method and application example 1.
[0033] Figure 4 This is a spherical aberration electron microscope image of Ag@CuONWs array material prepared by copper oxide nanowire-supported silver single-atom catalyst, preparation method and application example 1 of this invention;
[0034] Figure 5 These are data graphs of the electrocatalytic reduction of 4-nitrophenol in Examples 4 and 5 of this invention, which describe a silver single-atom catalyst supported on copper oxide nanowires, its preparation method, and its application.
[0035] Figure 6 This is the UV quantitative calibration diagram of 4-aminophenol in Example 4 of the present invention, which describes a silver single-atom catalyst supported on copper oxide nanowires, its preparation method, and its application.
[0036] Figure 7 This is a Faraday efficiency plot of a copper oxide nanowire-supported silver single-atom catalyst, its preparation method, and application example 4 of this invention;
[0037] Figure 8 This is a Faraday efficiency diagram of the copper oxide nanowire-supported silver single-atom catalyst, its preparation method, and application examples 4 and 5 of this invention. Detailed Implementation
[0038] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.
[0039] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.
[0040] Example 1
[0041] A method for preparing a silver single-atom catalyst supported on copper oxide nanowires includes the following steps:
[0042] S1. Pretreatment of copper foam substrate: The copper foam (1*2cm) was cleaned with 1mol / L hydrochloric acid, deionized water and anhydrous ethanol for 15 minutes in sequence to remove the grease and oxide layer on the surface, and then dried in a vacuum oven at 60℃ for 2 hours.
[0043] S2. CuO nanowires were obtained by in-situ growth on a copper foam substrate using an electrochemical oxidation method.
[0044] S21. Preparation of Cu(OH)₂NWs array material: Electrochemical oxidation was performed using a three-electrode system (platinum sheet as counter electrode, copper foam as working electrode, and Ag / AgCl as reference electrode). An H-type electrolytic cell was selected, wherein the electrolyte was a 1-3M potassium hydroxide solution, preferably a 3M potassium hydroxide solution, and the constant current was 40 mA cm⁻¹. -2Electrochemical oxidation was performed using a three-electrode system for 2400 s to obtain Cu(OH)2NWs array material on the surface of copper foam.
[0045] S22. Preparation of CuO nanowire material: The Cu(OH)₂NW array obtained in step S2 was rinsed three times with deionized water and anhydrous ethanol, respectively, and dried in a vacuum oven at 60℃ for 2 hours. It was then placed in a small porcelain boat and annealed in a muffle furnace. The heating rate was 5℃ / min, and the temperature was raised to 350℃ and held for 120 minutes to obtain CuO nanowire material.
[0046] S3. Ag@CuONWs array material was obtained by in-situ growth of single Ag atoms on the surface of CuO nanowires using chemical deposition. Specifically, 1.433 g of silver chloride and acetonitrile solution were dissolved in a 1 L volumetric flask to prepare a 10 mM AgCl-acetonitrile solution. Using the AgCl-acetonitrile solution as the electrolyte, electrochemical deposition was performed on the surface of CuO nanowires for 1 h. The material was then removed, allowed to stand, and washed three times with deionized water and anhydrous ethanol, respectively, to remove excess silver chloride and acetonitrile from the surface. The material was then dried in a vacuum oven at 60 °C for 2 h to obtain Ag@CuONWs array material with no silver chloride and acetonitrile on the surface.
[0047] Example 2
[0048] Unlike Example 1, in S3, Ag@CuONWs array material was obtained by in-situ growth of single Ag atoms on the surface of CuO nanowires using chemical deposition. Specifically, 0.718 g of silver chloride and acetonitrile solution were dissolved in a 1 L volumetric flask to prepare a 5 mM AgCl acetonitrile solution. Using the AgCl acetonitrile solution as the electrolyte, electrochemical deposition was performed on the surface of CuO nanowires for 1 h. The material was then removed, allowed to stand, and washed three times with deionized water and anhydrous ethanol, respectively, to remove excess silver chloride and acetonitrile from the surface. The material was then dried in a vacuum oven at 60 °C for 2 h to obtain Ag@CuONWs array material with no silver chloride and acetonitrile on the surface.
[0049] Example 3
[0050] Unlike Example 1, in S3, Ag@CuONWs array material was obtained by in-situ growth of single Ag atoms on the surface of CuO nanowires using chemical deposition. Specifically, 2.866 g of silver chloride and acetonitrile solution were dissolved in a 1 L volumetric flask to prepare a 20 mM AgCl-acetonitrile solution. Using the AgCl-acetonitrile solution as the electrolyte, electrochemical deposition was performed on the surface of CuO nanowires for 0.5 h. The material was then removed, allowed to stand, and washed three times with deionized water and anhydrous ethanol, respectively, to remove excess silver chloride and acetonitrile from the surface. The material was then dried in a vacuum oven at 60 °C for 2 h to obtain Ag@CuONWs array material with no silver chloride and acetonitrile on the surface.
[0051] Example 4
[0052] A method for the electrocatalytic reduction of 4-nitrophenol using a copper oxide nanowire-supported silver single-atom catalyst (Ag@CuONWs array material) prepared in Example 1 is as follows: an H-type electrolytic cell is used as the reaction apparatus, an ultraviolet spectrophotometer is used as the reaction product detection device, the Ag@CuONWs array material is used as the working electrode, a platinum sheet is used as the counter electrode, an Ag / AgCl electrode is used as the reference electrode, a 1.5M potassium bicarbonate solution is used as the electrolyte, and 10mM p-nitrophenol is added to the electrolyte to carry out the electrocatalytic reaction.
[0053] Example 5
[0054] Unlike Example 4, commercially available copper-based catalysts, such as copper foam (CuONWs), were used as the working electrode.
[0055] Test
[0056] The structure of the Ag@CuONWs array material prepared in Example 1 was confirmed:
[0057] Depend on Figure 1 As can be seen from the comparison with standard cards for copper oxide and silver, the shift in the main characteristic peak of copper oxide indicates that the prepared Ag@CuONWs array material already has Ag single-atom loading. Figure 2 It can be seen that the prepared Ag@CuONWs array material is a three-dimensional array structure. From Figure 3 , 4 This indicates that the prepared Ag@CuONWs array material nanowire structure is loaded with single atoms.
[0058] The reduction performance of the electrocatalyst (Ag@CuONWs) prepared in Example 1 and commercially available copper-based catalyst, copper foam (CuONWs), in reducing 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) was tested.
[0059] Figure 5 This is a graph showing the electrocatalytic reduction of p-nitrophenol using the Ag@CuONWs array material prepared in Example 1. From... Figure 5 The linear sweep voltammetry curves show that, compared to the CuONWs array, the Ag@CuONWs array exhibits a 4-nitrophenol reduction current at a lower potential.
[0060] Figure 6 The reduction product of 4-nitrophenol, 4-aminophenol, was calibrated using a UV-Vis quantitative standard using a UV spectrophotometer. Further quantification was then performed using the standard. Figure 7 The Faraday efficiency curve shown has negligible error.
[0061] like Figure 8 As shown in the Faraday efficiency diagram of the reduction products of 4-nitrophenol, it can be seen that at the same potential, the electrocatalytic performance of CuONWs modified with silver single atoms is far superior to that of CuONWs without silver single atoms, proving that CuONWs modified with silver single atoms have a good electrocatalytic synergistic effect. This is of great significance for improving the performance of copper-based catalysts and provides a new idea for the future application of single atoms in the field of electrocatalytic reduction of nitrophenol.
[0062] Therefore, this invention employs the above-mentioned copper oxide nanowire-supported silver single-atom catalyst, preparation method, and application. Through silver single-atom modification, the interaction between copper and silver metals jointly regulates the adsorption of intermediate products in the electrocatalytic reduction process, thereby obtaining excellent electrocatalytic nitrophenol reduction performance, which is suitable for the fields of environmental pollution control and pharmaceutical synthesis development.
[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.
Claims
1. An application of a silver single-atom catalyst supported on copper oxide nanowires, characterized in that, The copper oxide nanowire-supported silver single-atom catalyst is used for the electrocatalytic reduction reaction of p-nitrophenol; The copper oxide nanowire-supported silver single-atom catalyst includes a substrate, CuO nanowires, and metal Ag single atoms supported on the CuO nanowire electrode layer. The substrate is commercially available copper foam, which is used to provide a copper source for preparing array materials loaded with single Ag atoms on CuO nanowires. The preparation method of the copper oxide nanowire-supported silver single-atom catalyst includes the following steps: S1. Pretreatment of copper foam substrate; S2. CuO nanowires were obtained by in-situ growth on a copper foam substrate using an electrochemical oxidation method. S3. Ag@CuONWs array material was obtained by in-situ growth of single Ag atoms on the surface of CuO nanowires using chemical deposition. In step S3, the chemical deposition method specifically includes: Silver chloride and acetonitrile were added in proportion to prepare AgCl acetonitrile solution. Using AgCl acetonitrile solution as electrolyte, electrochemical deposition was performed on CuO nanowire surface. The material was taken out, allowed to stand, and washed with deionized water and anhydrous ethanol respectively. After drying, Ag@CuONWs array material with no silver chloride and acetonitrile on the surface was obtained. The electrocatalysis specifically refers to: An H-type electrolytic cell was used, with Ag@CuONWs array material as the working electrode, platinum sheet as the counter electrode, and Ag / AgCl electrode as the reference electrode. p-Nitrophenol was added to the electrolyte in a certain proportion. The electrolyte is a carbonate solution, which is either potassium carbonate or potassium bicarbonate solution, and the concentration of the carbonate solution is 1M to 2M. The concentration of p-nitrophenol is 10 mM.
2. The application of the copper oxide nanowire-supported silver single-atom catalyst according to claim 1, characterized in that, In step S1, the pretreatment process is as follows: the foamed copper is cleaned sequentially with 1 mol / L hydrochloric acid, deionized water and anhydrous ethanol, and then dried to obtain foamed copper without grease and oxide layer on the surface.
3. The application of the copper oxide nanowire-supported silver single-atom catalyst according to claim 1, characterized in that, In step S2, the electrochemical oxidation method specifically involves: S21. Preparation of Cu(OH)2NWs array material: Electrochemical oxidation was carried out using a three-electrode system and an H-type electrolytic cell, with a platinum sheet as the counter electrode, copper foam as the working electrode, and Ag / AgCl as the reference electrode, and Cu(OH)2NWs array material was obtained on the surface of copper foam. S22. Preparation of CuO nanowire material: The Cu(OH)2NWs array material obtained in step S21 is washed with deionized water and anhydrous ethanol in sequence, dried and annealed to obtain CuO nanowire material.
4. The application of the copper oxide nanowire-supported silver single-atom catalyst according to claim 3, characterized in that, In step S21, the electrolyte is a 1-3M potassium hydroxide solution, and the constant current is 40 mA cm⁻¹. -2 The oxidation time is 2400s.
5. The application of the copper oxide nanowire-supported silver single-atom catalyst according to claim 3, characterized in that, In step S22, an annealing process is performed using a muffle furnace with a heating rate of 5°C / min, heating to 350°C, and holding at that temperature for 120 min.
6. The application of the copper oxide nanowire-supported silver single-atom catalyst according to claim 1, characterized in that, The concentration of the AgCl acetonitrile solution is 5–20 mM, and the deposition time is 0.5–1 h.