A method for rapidly preparing copper oxide nanowires and application thereof

Abstract

The application belongs to the technical field of photoelectrocatalytic materials, and particularly relates to an experimental method for rapidly preparing copper oxide nanowires and application thereof. The preparation method is as follows: using a copper mesh as a substrate, Cu(OH)2 nanowire arrays are rapidly prepared on the surface of the copper mesh through a constant-voltage anodization method, and CuO nanowire arrays are prepared in situ through rapid dehydration of the Cu(OH)2 through high-temperature heat treatment x Compared with the existing P-type semiconductor materials, the material has a wide visible light absorption range as a photoelectrocatalytic material, has good performance in the fields of photoelectrolysis of water to produce hydrogen and light-assisted Li-CO2 batteries, solves the problem of low light energy utilization, and is beneficial to separation of photo-generated electron-hole pairs, so that the copper oxide nanowire material can be used as a positive electrode material of the Li-CO2 battery to measure a charge-discharge voltage close to a theoretical value.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photoelectrocatalytic material preparation and photoelectrochemical technology of energy and environment, and particularly relates to an experimental method for rapidly preparing copper oxide nanowires and application thereof. BACKGROUND

[0002] With the increasing global energy demand and the gradual depletion of oil resources, solar energy as a kind of inexhaustible clean energy has great potential, and hydrogen energy as an important clean energy, through water splitting and photoelectrochemical water splitting to produce hydrogen has become a research hotspot. In an ideal case, the Fermi level of the semiconductor in the photoelectrochemical water splitting cell is balanced with the redox potential of the electrolyte solution, resulting in band bending and generating an electric field. In terms of hydrogen production, p-type semiconductors have an advantage over n-type semiconductors. On the p-type semiconductor, electrons can be directly injected into the electrolyte, thereby directly reducing water to hydrogen at the interface of the p-type semiconductor. On the n-type semiconductor, the photo-generated electrons must migrate through an external circuit before they can be used to reduce water on the counter electrode, which involves potential energy loss. With the increasing importance of p-type oxide semiconductors in the field of energy materials, the number of p-type oxides available for selection is very small compared to n-type oxides. As a representative p-type oxide, copper oxide has attracted widespread attention in different research fields. In addition, one-dimensional nanostructures (such as nanowires, nanorods, nanotubes) have become a promising solution to the problem of mismatch between short carrier diffusion length and long light absorption depth of many semiconductors, because they can independently adjust the actual carrier diffusion length and light absorption depth of the semiconductor. Due to the unique photoelectric properties of nanowire structures, especially in terms of charge transport, they have become an important part of nanodevices and integrated nanosystems, and have an important position in the fields of catalysis and energy-related fields.

[0003] Copper oxide (CuO) as a p-type semiconductor with a narrow band gap (≤1.2eV), as well as a cornerstone of high-temperature superconductors and giant magnetoresistance materials, has always been a hot topic in the study of transition metal oxides. CuO nanowires have large surface area and potential size effect, and exhibit superior physical and chemical properties significantly different from their micron or bulk counterparts. Cuprous oxide (Cu2O) is also generally considered to be a material with a suitable band gap (about 2.0-2.2eV) and high carrier conductivity and mobility, and its specific physical and chemical properties depend largely on the corresponding preparation method. As a representative intrinsic p-type inorganic semiconductor material, Cu2O has been widely used in the fields of photovoltaics, catalysis, chemical industry, etc. Copper oxides (Cu xO) can be synthesized by various methods, including thermal oxidation method, thermal reduction method, chemical vapor deposition, electrochemical deposition, hydrothermal method, solvent reduction method, magnetron sputtering and pulsed laser deposition. In the production process, the constant voltage anodization method is simple and fast, and does not need to accurately calculate the surface area of the workpiece, only needs to set the voltage and time, which helps to reduce the production cost. The thermal oxidation method is the simplest and fastest synthesis method, and copper as raw material can be oxidized to Cu2O in an oxygen-free environment, and to CuO in an oxygen-containing environment.

[0004] In the preparation process, the method of combining anodization and high-temperature heat treatment can quickly obtain Cu x O nanowire array on the surface of copper mesh. This nanowire array structure not only increases the specific surface area, but also helps to increase the light contact area in photoelectric applications. The constant voltage anodization method effectively ensures the consistency of the nanowire structure, optimizes the contact between the nanowire and the substrate in situ, avoids the need for additional conductive agents and adhesives, and improves the overall performance of the battery. In summary, through this study, not only can a rapid experimental method for preparing copper oxide nanowires be provided, but also the process for preparing Cu x O nanowires is simple and efficient, and the application of the material provides important technical support for promoting energy transformation and environmental protection, which can effectively alleviate the global energy crisis and environmental pollution problems. SUMMARY

[0005] This section aims to summarize some aspects of the embodiments of the present application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification to avoid obscuring the purpose of this section, abstract and title, and such simplifications or omissions cannot be used to limit the scope of the present application.

[0006] In view of the above and / or existing problems in the preparation of photoelectrocatalytic materials and photoelectrochemical energy and environment, the present application is proposed.

[0007] Therefore, the purpose of the present application is to solve the problem that the surface current deviates due to the error of the surface area of the material in the anodization process of the copper mesh, which makes it difficult to maintain the consistency of the nanowire structure, and to provide a rapid experimental method for preparing copper oxide nanowires and its application. The experimental method is simple and controllable, and the constant voltage anodization method can quickly and stably prepare nanowires without calculating the surface current of the material. Through high-temperature annealing, copper hydroxide (Cu(OH)2) is in situ dehydrated / thermally induced to decompose into copper oxide (Cu x O), which is beneficial to the rapid preparation of Cu x O nanowire material without changing the nanostructure, and the prepared Cu xO nanowire materials are mainly used in photoelectric water splitting for hydrogen production and photo-assisted Li-CO2 batteries, exhibiting good photoelectric properties. Cu x O nanowire materials facilitate the separation of photogenerated electron and hole pairs, effectively solving the problem of low light energy utilization.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] An experimental method for rapid preparation of copper oxide nanowires and its application, characterized by comprising the following steps:

[0010] Step 1: Using deionized water as a solvent, KOH is added and stirred continuously to prepare the electrolyte for the anodic oxidation reaction. Dry nitrogen gas is then introduced to deoxygenate the electrolyte.

[0011] Step 2: Cut out copper mesh and copper sheets of the same size. First, degrease them in a mixed solution of NaOH and NaHCO3 for about 5 minutes. Then, prepare a polishing solution and polish the degreased copper mesh and copper sheets for about 20-30 seconds. Place them in a water washing solution for ultrasonic washing for about 10 minutes. Finally, use compressed air to dry the copper mesh and copper sheets to remove organic contaminants and oxide layers from their surfaces.

[0012] Step 3: In the electrochemical reactor of the two-electrode system, copper mesh and copper sheet are used as the anode and cathode, respectively. The copper mesh is subjected to electrochemical anodizing treatment under constant voltage. The temperature range of the electrochemical reactor is controlled between 20 and 30°C using a rotary evaporator to rapidly prepare Cu(OH)2 nanowire arrays on the surface of the copper mesh. After constant-pressure anodizing treatment, the Cu(OH)2 mesh is rinsed with deionized water and then dried using compressed air.

[0013] Step 4: A Cu(OH)₂ mesh is vertically placed inside a quartz crucible in a tube furnace and heat-treated under an argon atmosphere. After high-temperature annealing, Cu is produced. x O nanowires;

[0014] Step 5: Prepare a 0.1 mol / L Na₂SO₄ test solution, deoxygenate the solution with dry nitrogen gas, and then prepare the Cu in the three-electrode electrochemical reaction apparatus. x Using an O-grid as the working electrode, a Pt sheet as the counter electrode, and an AgCl electrode as the reference electrode, the photoelectrochemical properties of the material were tested under xenon lamp irradiation. Cu, which exhibits the highest photocurrent, was selected as the electrode. x O-grids have been applied in photocatalytic water splitting for hydrogen production and photo-assisted Li-CO2 batteries.

[0015] Further improvements to an experimental method for the rapid preparation of copper oxide nanowires and its applications include:

[0016] Preferably, the electrolyte for the anodic oxidation reaction in step 1 is a KOH solution with a concentration of 2 mol / L, and dry nitrogen gas is bubbled through it for at least 30 minutes.

[0017] Preferably, the degreasing solution in step 2 is a mixture of NaOH and NaHCO3 with a concentration of 1 mol / L, the polishing solution is prepared in the ratio of HF:HNO3:H2O=1:4:5 (vol%), and the washing solution is prepared in the ratio of C2H5OH:C3H6O:H2O=1:1:10 (vol%).

[0018] Preferably, in step 3, the voltage range for electrochemical anodizing of the copper mesh under constant voltage is 1.2~1.7V, and the reaction time is 200~1200 seconds.

[0019] Preferably, in step 4, the heat treatment temperature under an argon atmosphere is 200~600°C, the heating rate is 2°C / min, and the holding time is 2 hours.

[0020] Preferably, in step 5, Cu x In the application of O nanowire materials for photocatalytic water splitting to produce hydrogen, an H-type electrolyzer is used to collect hydrogen and oxygen, and Cu... x An O-mesh is used as the working electrode, a Pt sheet as the counter electrode, and an AgCl electrode as the reference electrode. An external voltage between -0.6V and -0.8V is applied, and Cu is exposed to a xenon lamp. x O nanowire materials for hydrogen production on one side; Cu nanowires are used in applications such as light-assisted Li-CO2 batteries. x The O-mesh is used as the positive electrode material, and the Li sheet is used as the negative electrode. A 1cm gap is reserved in the positive electrode casing of the battery. 2 The circular aperture allows the xenon lamp to directly irradiate the Cu. x The Li-CO2 battery was tested by placing the entire battery on the surface of the O material in a sealed chamber filled with pure CO2 at 0.03 MPa.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) Cu(OH)2 nanowire arrays were rapidly prepared on the surface of a copper mesh by constant voltage anodizing, and then Cu(OH)2 was rapidly dehydrated by high-temperature heat treatment to prepare Cu in situ. x The O nanowire array solves the problem that the surface current deviation caused by the error in the surface area of ​​the material during the anodizing process of copper mesh makes it difficult to maintain the consistent structure of the nanowires. The morphological characteristics are superior to those of nanowires prepared by current constant current anodizing. This method can complete the anodizing of large-area materials. The preparation process is simple, convenient and low in cost, which is conducive to industrial production.

[0023] (2) This invention uses copper mesh for preparing Cu x Cu was prepared from an O-based substrate through anodizing and high-temperature heat treatment. x O nanowire arrays, because each copper wire has a cylindrical three-dimensional structure, have higher performance than Cu nanowires prepared by traditional copper sheets and foils. x O nanowires have a higher specific surface area, allowing for the growth of more nanowires in a limited substrate space, while also facilitating access to more light in optoelectronic testing and applications.

[0024] (3) Prepared Cu x Copper oxide nanowires, as photoelectrocatalysts, have a wide visible light absorption range and exhibit good performance in photocatalytic water splitting for hydrogen production and photo-assisted Li-CO2 batteries. Copper oxide nanowires facilitate the separation of photogenerated electron and hole pairs, thus solving the problem of low light energy utilization in photoelectrocatalysts. Furthermore, this in-situ growth technique helps maintain good contact and adhesion between the nanowires and the substrate. The copper mesh substrate is used as a current collector, eliminating the need for additional conductive agents and binders, which ensures excellent battery performance. As a positive electrode material for Li-CO2 batteries, the test results show a charge-discharge voltage close to the theoretical value. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0026] Figure 1 This is a flowchart of the experimental method for rapidly preparing copper oxide nanowires according to the present invention.

[0027] Figure 2 The images show optical microscope (sub-image) and scanning electron microscope (SEM) images (main image) of Cu(OH)₂ nanowire materials prepared under conditions of 1.2V (a), 1.3V (b), 1.4V (c), 1.5V (d), 1.6V (e), and 1.7V (f) in Example 1 of this invention. The SEM images were taken at a magnification of 25000×. Figure 2 g、 Figure 2 h、 Figure 2 i, respectively corresponding to Figure 2 d、 Figure 2 e Figure 2 f is a Cu(OH)2 nanowire material photographed at 10000× magnification.

[0028] Figure 3The images show optical microscope (sub-image) and scanning electron microscope (main image) images of Cu(OH)2 nanowire materials prepared under conditions of 200 seconds (a), 400 seconds (b), 600 seconds (c), 800 seconds (d), 1000 seconds (e), and 1200 seconds (f) in Example 2 of this invention.

[0029] Figure 4 The Cu samples prepared in Example 3 of this invention at temperatures of 200℃ (a), 300℃ (b), 400℃ (c), 500℃ (d), 550℃ (e), and 600℃ (f) are examples of the Cu samples prepared in this invention. x Optical microscope image (sub-image) and scanning electron microscope image (main image) of O nanowire material, with the scanning electron microscope image taken at 25000× magnification. Figure 2 g、 Figure 2 h、 Figure 2 i, respectively corresponding to Figure 2 d、 Figure 2 e Figure 2 f is a Cu(OH)2 nanowire material photographed at 10000× magnification.

[0030] Figure 5 The images show the Raman curves (a) and X-ray diffraction curves (b) of Cu(OH)₂ nanowires prepared under different anodic oxidation voltages in Example 1 of this invention; the Raman curves (c) and X-ray diffraction curves (d) of Cu(OH)₂ nanowires prepared under different anodic oxidation time conditions in Example 2 of this invention; and the images show the Raman curves (c) and X-ray diffraction curves (d) of Cu(OH)₂ nanowires prepared under different annealing temperatures in Example 3 of this invention. x Raman curve (e) and X-ray diffraction curve (f) of O nanowire material.

[0031] Figure 6 The photoelectrochemical testing and application test diagram in Example 4 of this invention includes: Cu x Photocurrent curves (a), UV-Vis absorption curves (b), Tauc curves (c), Mott-Schottky curves (d), Cu under illumination conditions for O nanowire materials x A schematic diagram of the band structure of O nanowires (e), a diagram of hydrogen production effect (f), photocurrent and dark current curves (g) and charge-discharge cycle curves (h) of a light-assisted Li-CO2 battery. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. This invention will be described in more detail below through specific examples, but the scope of protection of this invention is not limited to these embodiments.

[0033] Example 1

[0034] This embodiment provides an experimental method for rapidly preparing copper hydroxide nanowires by controlling the anodic oxidation voltage, specifically including the following steps:

[0035] Step 1: Prepare a 2 mol / L KOH solution using deionized water as solvent. After continuous stirring, use it as the electrolyte for the anodic oxidation reaction. Blow dry nitrogen gas through the solution for at least 30 minutes to deoxygenate the electrolyte.

[0036] Step 2: Cut out copper mesh and copper sheets with dimensions of 2cm×3cm. First, degrease them in a mixed solution of NaOH and NaHCO3 with a concentration of 1mol / L for about 5 minutes. Then, prepare a polishing solution with a ratio of HF:HNO3:H2O=1:4:5 (vol%) and polish the degreased copper mesh and copper sheets for about 20~30 seconds. Then, place them in a water washing solution with a ratio of C2H5OH:C3H6O:H2O=1:1:10 (vol%) and ultrasonically wash them for about 10 minutes. Finally, use compressed air to dry the copper mesh and copper sheets to remove organic contaminants and oxide layers from their surfaces.

[0037] Step 3: In the electrochemical reactor with a two-electrode system, copper mesh and copper sheet were used as the anode and cathode, respectively. The copper mesh underwent electrochemical anodizing treatment under a constant voltage range of 1.2~1.7V for 600 seconds. The temperature of the electrochemical reactor was controlled between 20~30°C using a rotary evaporator to rapidly prepare Cu(OH)2 nanowire arrays on the surface of the copper mesh. After constant-voltage anodizing treatment, the Cu(OH)2 mesh was rinsed with deionized water and then dried using compressed air.

[0038] Figure 2 The images show optical microscope (sub-image) and scanning electron microscope (SEM) images (main image) of Cu(OH)₂ nanowire materials prepared under conditions of 1.2V (a), 1.3V (b), 1.4V (c), 1.5V (d), 1.6V (e), and 1.7V (f) in Example 1 of this invention. The SEM images were taken at a magnification of 25000×. Figure 2 g、 Figure 2 h、 Figure 2 i, respectively corresponding to Figure 2 d、 Figure 2 e Figure 2 f shows Cu(OH)₂ nanowires photographed at 10000× magnification. Comparing experimental conditions with different anodic oxidation voltages, the Cu(OH)₂ nanowires prepared at 1.4V have intact tips and are relatively long and densely distributed. Figure 5The Raman curves (a) and X-ray diffraction curves (b) of Cu(OH)2 nanowire materials prepared under different anodic oxidation voltage conditions in Example 3 of this invention show the characteristic peaks of Cu(OH)2 material. The peak value of the sample with a voltage of 1.4V is the highest.

[0039] Example 2

[0040] This embodiment provides an experimental method for rapidly preparing copper hydroxide nanowires by controlling the anodizing time, specifically including the following steps:

[0041] Step 1: Prepare a 2 mol / L KOH solution using deionized water as solvent. After continuous stirring, use it as the electrolyte for the anodic oxidation reaction. Blow dry nitrogen gas through the solution for at least 30 minutes to deoxygenate the electrolyte.

[0042] Step 2: Cut out copper mesh and copper sheets with dimensions of 2cm×3cm. First, degrease them in a mixed solution of NaOH and NaHCO3 with a concentration of 1mol / L for about 5 minutes. Then, prepare a polishing solution with a ratio of HF:HNO3:H2O=1:4:5 (vol%) and polish the degreased copper mesh and copper sheets for about 20~30 seconds. Then, place them in a water washing solution with a ratio of C2H5OH:C3H6O:H2O=1:1:10 (vol%) and ultrasonically wash them for about 10 minutes. Finally, use compressed air to dry the copper mesh and copper sheets to remove organic contaminants and oxide layers from their surfaces.

[0043] Step 3: In the electrochemical reactor of the dual-electrode system, copper mesh and copper sheet were used as the anode and cathode, respectively. The copper mesh was subjected to electrochemical anodizing treatment under a constant voltage for 200-1200 seconds at a voltage of 1.4V. The temperature range of the electrochemical reactor was controlled between 20-30°C using a rotary evaporator to rapidly prepare Cu(OH)₂ nanowire arrays on the surface of the copper mesh. After constant-pressure anodizing, the Cu(OH)₂ mesh was rinsed with deionized water and then dried using compressed air.

[0044] Figure 3 The images show optical microscope (sub-image) and scanning electron microscope (SEM) images (main image) of Cu(OH)₂ nanowires prepared under anodizing times of 200 seconds (a), 400 seconds (b), 600 seconds (c), 800 seconds (d), 1000 seconds (e), and 1200 seconds (f) in Example 2 of this invention. Comparing the experimental conditions with different anodizing times, the Cu(OH)₂ nanowires prepared at 800 seconds exhibit intact tips, longer length, and denser distribution. Figure 5The Raman curves (c) and X-ray diffraction curves (d) of Cu(OH)2 nanowire materials prepared under different anodizing time conditions in Example 2 of the present invention show the characteristic peaks of Cu(OH)2 material. The peak value of the sample with a time of 800s is the highest.

[0045] Example 3

[0046] This embodiment provides an experimental method for rapidly preparing copper oxide nanowires by controlling the annealing temperature, specifically including the following steps:

[0047] Step 1: Place the Cu(OH)2 mesh prepared by reacting under constant voltage anodizing conditions of 1.4V for 800s vertically in a quartz crucible, and place the quartz crucible containing the Cu(OH)2 mesh into a tube furnace;

[0048] Step 2: Heat treatment is performed under an argon atmosphere at a temperature of 200-600°C, a heating rate of 2°C / min, and a holding time of 2 hours. Cu is then prepared after high-temperature annealing. x O nanowires.

[0049] Figure 1 This is a flowchart of the experimental method for rapidly preparing copper oxide nanowires according to the present invention. This embodiment can be applied to all the steps in the flowchart. Figure 4 The Cu samples prepared in Example 3 of this invention at temperatures of 200℃ (a), 300℃ (b), 400℃ (c), 500℃ (d), 550℃ (e), and 600℃ (f) are examples of the Cu samples prepared in this invention. x Optical microscope image (sub-image) and scanning electron microscope image (main image) of O nanowire material, with the scanning electron microscope image taken at 25000× magnification. Figure 2 g、 Figure 2 h、 Figure 2 i, respectively corresponding to Figure 2 d、 Figure 2 e Figure 2 f shows Cu(OH)₂ nanowires photographed at 10000× magnification. Comparison of experimental conditions with different annealing temperatures, Cu annealed at 550℃... x The O nanowires have intact tips and are relatively long and densely distributed. Figure 5 The middle section shows Cu prepared at different annealing temperatures in Example 3 of the present invention. x The Raman curve (e) and X-ray diffraction curve (f) of O nanowire materials can be used to find the characteristic peaks of CuO and Cu2O materials. The peak value of the characteristic peak of the sample annealed at 550℃ is the highest.

[0050] Example 4

[0051] This embodiment provides a Cu xThe method for photoelectrochemical testing and application testing of O nanowires specifically includes the following steps:

[0052] Step 1: Prepare a test solution of Na2SO4 with a concentration of 0.1 mol / L, and bubble it with dry nitrogen gas for at least 30 minutes to deoxygenate the electrolyte;

[0053] Step 2: Select the sample prepared in Example 3 and cut it into Cu samples with dimensions of 1cm × 1cm. x O-grid, in a three-electrode electrochemical reaction device, Cu x Using an O-mesh as the working electrode and a Pt sheet as the counter electrode, an AgCl electrode as the reference electrode, Cu was tested under xenon lamp irradiation. x The photocurrent of the O nanowire, wherein the time interval between switching the xenon lamp is 50s;

[0054] Step 3: Select the sample prepared in Example 3 and cut it into Cu samples with a size of 1cm × 1cm. x The UV-Vis absorption of the material was measured using an O-grid in the wavelength range of 200 nm to 800 nm, and the absorption of Cu annealed at 550 °C was calculated. x Tauc curve of O nanowires;

[0055] Step 4: Select the sample prepared in Example 3 at an annealing temperature of 550℃ and cut it into Cu samples with dimensions of 1cm × 1cm. x O-grid, in a three-electrode electrochemical reaction device, Cu x Using an O-mesh as the working electrode and a Pt sheet as the counter electrode, an AgCl electrode as the reference electrode, Cu was tested. x The optical Mott-Schottky curve of O nanowires;

[0056] Step 5: Prepare an electrolyte solution with a concentration of 0.1 mol / L Na2SO4, and deoxygenate the electrolyte solution by bubbling with dry nitrogen gas for at least 30 minutes. Select samples prepared under the annealing temperatures of 500℃, 550℃, and 600℃ in Example 3, and cut them into Cu samples with a size of 1cm × 1cm. x O-grid, using an H-type electrolytic cell to collect hydrogen and oxygen, Cu x An O-mesh is used as the working electrode, a Pt sheet as the counter electrode, and an AgCl electrode as the reference electrode. An external voltage between -0.6V and -0.8V is applied, and Cu is exposed to a xenon lamp. x Hydrogen is produced on one side of the O nanowire material, where a proton exchange membrane separates the hydrogen and oxygen production solutions in the middle of an H-type electrolyzer. Rhodamine B (RhB) is added to one side of the Pt sheet for electrochemical degradation, while Cu... x Photoelectrochemical hydrogen production on one side of the O-grid;

[0057] Step 6: Select the sample prepared in Example 3 at an annealing temperature of 550°C and cut it into circular Cu samples with a diameter of 1.1 cm. x The O-mesh is used as the positive electrode material, and the Li sheet is used as the negative electrode. A 1cm gap is left in the positive electrode casing of the battery. 2 The circular aperture allows the xenon lamp to directly irradiate the Cu. x The Li-CO2 battery was placed on the surface of the O material and placed in a sealed chamber of pure CO2 at 0.03 MPa. The discharge voltage of the light-assisted Li-CO2 battery was tested under discharge conditions, with the time interval between switching the xenon lamp on and off being 100 s.

[0058] Step 7: Select the sample prepared in Example 3 at an annealing temperature of 550°C and cut it into circular Cu samples with a diameter of 1.1 cm. x The O-mesh is used as the positive electrode material, and the Li sheet is used as the negative electrode. A 1cm gap is left in the positive electrode casing of the battery. 2 The circular aperture allows the xenon lamp to directly irradiate the Cu. x The Li-CO2 battery was placed on the surface of the O material and placed in a sealed chamber of pure CO2 at 0.03 MPa. The cycle performance of the light-assisted Li-CO2 battery was tested under continuous xenon lamp irradiation. The constant current charge and discharge current was 0.01 mA and the charge and discharge time was 1 h.

[0059] Figure 6 The following is a diagram illustrating the photoelectrochemical testing and application testing in Example 4 of this invention, as shown. Figure 6 Cu shown in a x The photocurrent curves of the O nanowire materials show that the sample prepared in Example 3 with an annealing temperature of 550℃ has the highest photocurrent; for example... Figure 6 Cu shown in a x The UV-Vis absorption curves of the O nanowire material show that the sample prepared at an annealing temperature of 550℃ in Example 3 has the highest absorption intensity. The Tauc curve of this sample (e.g.) is plotted. Figure 6 (as shown in c) and the Mott-Schottky curve (as shown in c) Figure 6 As shown in d), the Cu under illumination conditions was obtained through the collation and calculation of experimental data. x A schematic diagram of the energy band structure of O nanowires (e.g.) Figure 6 (as shown in e). Applications of photoelectric water splitting for hydrogen production include... Figure 6 The hydrogen production effect diagram shown in f indicates that adding Rhodamine B (Rh B) to one side of the Pt sheet can effectively promote Cu production while simultaneously facilitating electrochemical degradation. x Photoelectrochemical hydrogen production was achieved on the O-grid side, with the sample prepared in Example 3 at an annealing temperature of 550°C showing the best hydrogen production performance. For applications of light-assisted Li-CO2 cells, such as… Figure 6 g and Figure 6As shown in f, the photocurrent and dark current curves and charge-discharge cycle curves of the light-assisted Li-CO2 battery all showed charge-discharge voltages close to the theoretical values, proving that Cu x O nanowire materials solve the problem of low light energy utilization and are beneficial for the separation of photogenerated electron and hole pairs.

[0060] Summary: This invention relates to the field of photoelectrochemical technology for the preparation of photoelectrocatalytic materials and energy and environmental applications, particularly to an experimental method for the rapid preparation of copper oxide nanowires and their applications. The application of copper oxide nanowire materials in photo-assisted Li-CO2 batteries is a promising solution to energy and environmental problems. Copper mesh is used to prepare Cu… x Cu was prepared from an O-based substrate through anodizing and high-temperature heat treatment. x O nanowire arrays, because each copper wire has a cylindrical three-dimensional structure, have higher performance than Cu nanowires prepared by traditional copper sheets and foils. x Cu(OH)₂ nanowires have a higher specific surface area, allowing for the growth of more nanowires within a limited substrate space. This also facilitates greater light exposure in optoelectronic testing and applications. A constant-voltage anodizing method rapidly fabricates Cu(OH)₂ nanowire arrays on copper mesh surfaces, overcoming the limitation of inconsistent nanowire structures caused by surface current deviations due to surface area errors in copper mesh anodizing. The resulting nanowires exhibit superior morphology compared to those prepared using constant-current anodizing. This method allows for the anodizing of larger areas, is simple and convenient, and has low production costs, making it suitable for industrial production. High-temperature heat treatment rapidly dehydrates Cu(OH)₂, leading to the in-situ preparation of Cu... x O nanowire arrays, this in-situ growth technique helps maintain good contact and adhesion between the nanowires and the substrate. The copper mesh substrate serves as the current collector, eliminating the need for additional conductive agents and binders, thus ensuring excellent battery performance. As a positive electrode material for Li-CO2 batteries, it achieved charge-discharge voltages close to theoretical values ​​in testing. The prepared Cu... x O nanowire materials, as photoelectrocatalysts, possess a wide visible light absorption range and exhibit good hydrogen production performance in photocatalytic water splitting. Furthermore, they can effectively promote Cu production while simultaneously performing electrochemical degradation on the oxygen-producing side. x The photoelectrochemical hydrogen production on one side of the O-grid generates clean energy while simultaneously degrading pollutants, representing a new approach to solving energy and environmental problems.

[0061] Although the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description should not be considered as a limitation of the present invention.

Claims

1. An experimental method for rapid preparation of copper oxide nanowires, characterized in that, Includes the following steps: Step 1: Using deionized water as a solvent, KOH is added and stirred continuously to prepare the electrolyte for the anodic oxidation reaction. Dry nitrogen gas is then introduced to deoxygenate the electrolyte. Step 2: Cut out copper mesh and copper sheets of the same size. First, degrease them in a mixed solution of NaOH and NaHCO3. Then, prepare a polishing solution with a ratio of HF:HNO3:H2O = 1:4:5 (vol%) and polish the degreased copper mesh and copper sheets for 20-30 seconds. Then, place them in a water washing solution with a ratio of C2H5OH:C3H6O:H2O = 1:1:10 (vol%) and ultrasonically wash them for about 10 minutes. Finally, use compressed air to dry the copper mesh and copper sheets to remove organic contaminants and oxide layers from their surfaces. Step 3: In the electrochemical reaction device of the dual electrode system, copper mesh and copper sheet are used as anode and cathode respectively. The copper mesh is subjected to electrochemical anodizing treatment under constant voltage. The temperature range of the electrochemical reaction device is controlled between 20 and 30°C using a rotary evaporator. Cu(OH)2 nanowire array is rapidly prepared on the surface of copper mesh. After constant pressure anodizing treatment, Cu(OH)2 mesh is rinsed with deionized water and then dried using compressed air. Step 4: The Cu(OH)2 mesh is placed vertically in a quartz crucible in a tube furnace and heat-treated under an argon atmosphere. After high-temperature annealing, CuxO nanowires are prepared. Step 5: Prepare a test solution of Na2SO4 with a concentration of 0.1 mol / L, deoxygenate the solution with dry nitrogen gas, use CuxO mesh as working electrode, Pt sheet as counter electrode and AgCl electrode as reference electrode in the three-electrode electrochemical reaction device, test the photoelectrochemical performance of the material under xenon lamp irradiation, and select CuxO mesh with the largest photocurrent for application in photo-split water to produce hydrogen and photo-assisted Li-CO2 battery respectively; In step 4, the heat treatment is carried out in an argon atmosphere at a temperature of 550℃, a heating rate of 2℃ / min, and a holding time of 2 hours.

2. The experimental method for rapid preparation of copper oxide nanowires according to claim 1, characterized in that, In step 1, the electrolyte for the anodic oxidation reaction is a 2 mol / L KOH solution, and dry nitrogen gas is bubbled through it for at least 30 minutes.

3. The experimental method for rapid preparation of copper oxide nanowires according to claim 1, characterized in that, In step 2, the degreasing solution is a mixture of NaOH and NaHCO3 with a concentration of 1 mol / L, and the degreasing time is 300-600 seconds.

4. The experimental method for rapid preparation of copper oxide nanowires according to claim 1, characterized in that, In step 3, the voltage range for electrochemical anodizing of the copper mesh under constant voltage is 1.2–1.7V, and the reaction time is 200–1200 seconds.

5. The application of the rapid preparation of copper oxide nanowires according to claim 1, characterized in that, The application of copper oxide nanowires in light-assisted Li-CO2 batteries in step 5.

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