Preparation method of nano copper oxide sheet

Abstract

The present disclosure provides a method for preparing nano copper oxide flakes, and relates to the technical field of metal powder nanomaterial preparation. The method comprises: configuring copper salt into a copper precursor aqueous solution containing a surfactant, and configuring alkali into an alkaline solution; converting the copper precursor aqueous solution containing a surfactant into a copper micro-nano aerosol containing a surfactant, and converting the alkaline solution into an alkali-containing micro-nano aerosol; performing a gas phase confined micro-region mixing pre-reaction on the copper micro-nano aerosol containing a surfactant and the alkali-containing micro-nano aerosol to obtain a copper-alkali mixed solution, and transferring the copper-alkali mixed solution to a polytetrafluoroethylene reactor for hydrothermal reaction to obtain a nanoparticle solution containing a copper compound; performing solid-liquid separation, washing, drying and roasting on the nanoparticle solution containing a copper compound to obtain a nano copper oxide flake. The present disclosure reduces the preparation cost of the nano copper oxide flake on the basis of improving the preparation efficiency of the nano copper oxide flakes.

Description

Technical Field

[0001] The present disclosure relates to the technical field of metal powder nanomaterial preparation, and in particular to a method for preparing a nano copper oxide sheet. Background Art

[0002] In the existing schemes, the preparation methods of nano copper oxide sheets mainly include liquid phase method, electrochemical method and chemical vapor deposition (CVD, Chemical Vapor Deposition), etc. However, although a variety of preparation methods for nano copper oxide sheets have been developed in the laboratory, how to achieve low-cost and efficient large-scale industrial production still faces many challenges.

[0003] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0004] In view of this, a method for preparing nano copper oxide sheets is provided, thereby overcoming the problems of low preparation efficiency and high preparation cost of nano copper oxide sheets caused by limitations and defects of related technologies, at least to a certain extent.

[0005] According to one aspect of the present disclosure, a method for preparing a nano copper oxide sheet is provided, the method comprising the following steps:

[0006] Step 1: Under the action of magnetic stirring, the copper salt is configured as a copper precursor aqueous solution containing a surfactant, and the base is configured as an alkaline solution;

[0007] Step 2: using a high-frequency electronic oscillation device to convert the copper precursor aqueous solution containing a surfactant into a copper micro-nano aerosol containing a surfactant, and to convert the alkaline solution into an alkali-containing micro-nano aerosol;

[0008] Step 3, performing a gas phase confined micro-area mixing pre-reaction on the copper micro-nano aerosol containing a surfactant and the micro-nano aerosol containing an alkali to obtain a copper-alkali mixed solution, and transferring the copper-alkali mixed solution to a polytetrafluoroethylene reactor for hydrothermal reaction to obtain a nanoparticle solution containing a copper compound;

[0009] Step 4: performing solid-liquid separation, washing, drying and calcining on the nanoparticle solution containing the copper compound to obtain the nano copper oxide sheet.

[0010] In an exemplary embodiment of the present disclosure, the copper salt includes copper salt which is at least one of copper chloride, copper acetate, copper sulfate and copper nitrate;

[0011] The concentration of the copper precursor aqueous solution containing the surfactant is less than or equal to 70 g / L; wherein the concentration is the total concentration of the surfactant and the copper salt.

[0012] In an exemplary embodiment of the present disclosure, the surfactant includes at least one of polyethylene glycol, polyvinyl pyrrolidone, cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, sodium dodecylbenzene sulfonate, polydiallyldimethylammonium chloride and polysorbate.

[0013] In an exemplary embodiment of the present disclosure, the alkaline aqueous solution is at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate and ammonia water;

[0014] The concentration of the alkaline aqueous solution is less than or equal to 100 g / L;

[0015] The pH value of the alkaline hydration solution is between 7 and 9, which is in a weakly alkaline state.

[0016] In an exemplary embodiment of the present disclosure, the oscillation frequency of the high-frequency electronic oscillation device is less than or equal to 4 MHz;

[0017] The copper micro-nano aerosol containing surfactant is composed of ultra-fine nano-droplets with an average size of less than or equal to 10 μm;

[0018] The alkali-containing micro-nano aerosol is composed of ultra-fine nano-droplets with an average size of less than or equal to 10 μm.

[0019] In an exemplary embodiment of the present disclosure, the gas phase confined micro-region mixing pre-reaction is carried out at room temperature;

[0020] In the process of gas phase confinement micro-region mixing pre-reaction, micro-region mixing needs to be carried out in the gas phase confinement less than 20 μm.

[0021] In an exemplary embodiment of the present disclosure, in the process of transferring the copper-alkali mixed solution to a polytetrafluoroethylene reactor for hydrothermal reaction to obtain a nanoparticle solution containing copper compounds, the temperature of the hydrothermal reaction is 100°C~200°C, the pressure in the polytetrafluoroethylene reactor is between 3~10 MPa, and the hydrothermal reaction time is 1~10h.

[0022] In an exemplary embodiment of the present disclosure, during the solid-liquid separation of the nanoparticle solution containing the copper compound, the solid-liquid separation method used is centrifugal separation and / or suction filtration separation;

[0023] In the process of washing the separated nanoparticles containing copper compounds, the washing solution used is water and / or ethanol;

[0024] In the process of drying the washed copper compound-containing nanoparticles, the drying method used is thermal drying and / or freeze drying;

[0025] In the process of calcining the dried copper compound-containing nanoparticles, the calcination temperature used is 200°C~500°C, the atmosphere used is air, and the calcination time is 2h.

[0026] In an exemplary embodiment of the present disclosure, in the obtained nano copper oxide flakes, the size of a single nano copper oxide flake is 1-4 μm, the average size is 2 μm, and the thickness of a single sheet is about 30-60 nm.

[0027] In an exemplary embodiment of the present disclosure, the prepared nano copper oxide sheet is used to prepare at least one of the following materials:

[0028] Catalysts, energy storage materials, sensors, environmental management materials, electronic devices and biomedical materials.

[0029] In a method for preparing a nano copper oxide sheet provided in an exemplary embodiment of the present disclosure, on the one hand, under the action of magnetic stirring, the copper salt is configured as a copper precursor aqueous solution containing a surfactant, and the alkali is configured as an alkaline solution; then, a high-frequency electronic oscillation device is used to convert the copper precursor aqueous solution containing a surfactant into a copper micro-nano aerosol containing a surfactant, and the alkaline solution is converted into an alkali-containing micro-nano aerosol; then, the copper micro-nano aerosol containing a surfactant and the alkali-containing micro-nano aerosol are subjected to a gas phase confined micro-area mixing pre-reaction to obtain a copper-alkali mixed solution, and the copper-alkali mixed solution is transferred to a polytetrafluoroethylene reactor for hydrothermal reaction to obtain nanoparticles containing copper compounds. solution; finally, the nanoparticle solution containing the copper compound is subjected to solid-liquid separation, washing, drying and roasting to obtain nano copper oxide sheets. Since a common water-soluble copper precursor can be used as a copper source, a low-cost water-soluble organic matter is used as a surfactant, and an ordinary alkaline solution is used as a control agent for regulating the nucleation and growth of crystals, the nano copper oxide sheets can be prepared, thereby reducing the preparation cost of the nano copper oxide sheets; on the other hand, by converting the copper source and the alkali into a micro-nano aerosol form for reaction, a three-dimensional space confined micro-area reaction condition is constructed, and the material transport and reaction kinetics conditions are controlled, the morphology of the nano copper oxide sheets can be controlled, thereby improving the preparation efficiency of the nano copper oxide sheets.

[0030] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0032] Figure 1 The following is a schematic diagram showing a process flow of a method for preparing a nano copper oxide sheet according to an exemplary embodiment of the present disclosure.

[0033] Figure 2 The SEM image of a nano copper oxide sheet obtained based on Example 1 according to an exemplary embodiment of the present disclosure is schematically shown.

[0034] Figure 3 A size distribution diagram of nano copper oxide flakes obtained based on Example 1 according to an exemplary embodiment of the present disclosure is schematically shown.

[0035] Figure 4 The XRD (i.e., a spectrum of material structure analysis obtained by X-ray diffraction technology) diagram of a nano copper oxide sheet obtained based on Example 1 according to an exemplary embodiment of the present disclosure is schematically shown.

[0036] Figure 5 A SEM image of a copper oxide nanosheet obtained based on Comparative Example 1 according to an exemplary embodiment of the present disclosure is schematically shown.

[0037] Figure 6 A SEM image of a copper oxide nanosheet obtained based on Comparative Example 2 according to an exemplary embodiment of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0038] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description will be omitted. In addition, the drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale.

[0039] The terms "a", "an", "the", "said" and "at least one" are used to indicate the presence of one or more elements / components / etc.; the terms "including" and "having" are used to express an open-ended inclusive meaning and mean that additional elements / components / etc. may exist in addition to the listed elements / components / etc.; the terms "first", "second" and "third" etc. are used merely as labels and are not intended to limit the quantity of their objects.

[0040] Copper oxide is an important inorganic compound, black or brown-black, and is a divalent oxide of copper. In practical applications, copper oxide can be widely used in sensors, catalysts, and battery materials due to its unique physical and chemical properties. At the same time, in the field of nanomaterials, precise control of morphology and size has a crucial influence on material properties; for this reason, a large number of studies in related programs are focused on the development of copper oxide nanomaterials (such as nanorods, nanowires, nanosheets) and copper nanosheets with various morphologies to optimize their physical and chemical properties.

[0041] Nano copper oxide sheets are two-dimensional nanomaterials composed of copper elements. Their thickness is usually between tens and hundreds of nanometers, and their lateral dimensions are much larger than their thickness. At the same time, with their unique two-dimensional geometric structure, copper nanosheets show significant differences in physical, chemical and electrical properties compared with traditional copper materials, showing broad application prospects. In the existing schemes, the preparation methods of nano copper oxide sheets mainly include liquid phase method, electrochemical method and chemical vapor deposition (CVD, Chemical Vapor Deposition). For example, in the process of preparing copper nanosheets by liquid phase chemical reduction method, sodium citrate can be used as a reducing agent and passivating agent to reduce copper sulfate solution to prepare copper nanosheets with good morphology; electrochemical deposition technology can grow copper nanosheets on specific substrates, which has the significant advantage of accurately controlling the thickness and size of nanosheets; and the CVD method is suitable for large-scale preparation of nano copper oxide sheets, which can ensure the uniformity and high quality of the product.

[0042] Although a variety of methods for preparing nano-copper oxide sheets have been developed in the laboratory, there are still many challenges in achieving low-cost, efficient, large-scale industrial production.

[0043] Based on this, the exemplary embodiment of the present disclosure first provides a method for preparing a nano copper oxide sheet. Specifically, refer to Figure 1 As shown, the method for preparing the nano copper oxide sheet may include the following steps:

[0044] Step S110. Under the action of magnetic stirring, the copper salt is configured as a copper precursor aqueous solution containing a surfactant, and the base is configured as an alkaline solution;

[0045] Step S120. using a high-frequency electronic oscillation device to convert the copper precursor aqueous solution containing a surfactant into a copper micro-nano aerosol containing a surfactant, and to convert the alkaline solution into an alkali-containing micro-nano aerosol;

[0046] Step S130. Performing a gas phase confined micro-area mixing pre-reaction on the copper micro-nano aerosol containing a surfactant and the micro-nano aerosol containing an alkali to obtain a copper-alkali mixed solution, and transferring the copper-alkali mixed solution to a polytetrafluoroethylene reactor for hydrothermal reaction to obtain a nanoparticle solution containing a copper compound;

[0047] Step S140: performing solid-liquid separation, washing, drying and calcining on the nanoparticle solution containing the copper compound to obtain the nano copper oxide sheet.

[0048] In the preparation method of the nano copper oxide sheet described above, on the one hand, under the action of magnetic stirring, the copper salt is configured as a copper precursor aqueous solution containing a surfactant, and the alkali is configured as an alkaline solution; then, a high-frequency electronic oscillation device is used to convert the copper precursor aqueous solution containing a surfactant into a copper micro-nano aerosol containing a surfactant, and the alkaline solution is converted into an alkali-containing micro-nano aerosol; then, the copper micro-nano aerosol containing a surfactant and the alkali-containing micro-nano aerosol are subjected to a gas phase confined micro-region mixing pre-reaction to obtain a copper-alkali mixed solution, and the copper-alkali mixed solution is transferred to a polytetrafluoroethylene reactor for hydrothermal reaction to obtain a nanoparticle solution containing copper compounds; and finally, The nanoparticle solution containing the copper compound is then subjected to solid-liquid separation, washing, drying and calcination to obtain nano-copper oxide sheets. Since common water-soluble copper precursors can be used as copper sources, low-cost water-soluble organic matter can be used as surfactants, and ordinary alkaline solutions can be used as control agents for regulating crystal nucleation and growth, the nano-copper oxide sheets can be prepared, thereby reducing the preparation cost of the nano-copper oxide sheets. On the other hand, by converting the copper source and the alkali into micro-nano aerosol forms for reaction, three-dimensional spatial confined micro-area reaction conditions are constructed, and the material transport and reaction kinetics conditions are controlled, the morphology of the nano-copper oxide sheets can be controlled, thereby improving the preparation efficiency of the nano-copper oxide sheets.

[0049] Hereinafter, the method for preparing the nano copper oxide sheet described in the exemplary embodiment of the present disclosure will be further explained and illustrated in conjunction with the accompanying drawings.

[0050] First, the technical implementation principle of the exemplary embodiment of the present disclosure is explained and illustrated. Specifically, in the preparation method of the nano copper oxide flakes recorded in the exemplary embodiment of the present disclosure, first, a copper salt aqueous solution and an alkaline solution containing a surfactant are prepared to create favorable conditions for the nano-scale dispersion of the copper salt and the regulation of crystal nucleation and growth; then, high-frequency electronic oscillation technology is used to convert them into copper micro-nano aerosols containing surfactants and micro-nano aerosols containing alkali formed by ultra-fine nano droplets, respectively, to construct a confined micro-area mixing environment, and then a hydrothermal synthesis method is used to optimize the reaction kinetic conditions of crystal growth by changing the reaction temperature, time, pressure and pH value, so as to strengthen the transmission and crystal growth mode during the reaction of the copper source and the alkali, thereby obtaining nanoparticles of copper-containing compounds through nano-scale reactions, and then through solid-liquid separation, washing, drying and roasting, decomposition to obtain nano copper oxide flakes, and the morphology and size of the nano copper oxide flakes are regulated. Furthermore, in the specific preparation process, a common water-soluble copper precursor can be used as a copper source, a low-cost water-soluble organic matter can be used as a surfactant, and an ordinary alkaline solution can be used as a control agent for regulating the nucleation and growth of crystals. By changing factors such as reaction temperature, time, pressure and pH value, the moderate nucleation density and growth rate in the crystal growth process can be increased, and uniform growth can be carried out along a specific crystal plane to form a sheet structure, thereby ultimately achieving a high-yield and controllable preparation of nano copper oxide and copper. At the same time, the preparation method of the nano copper oxide sheet recorded in the exemplary embodiment of the present disclosure has a simple preparation process, relatively mild reaction conditions, low production cost, environmental friendliness, and a thin thickness of the prepared nano copper oxide sheet, which is conducive to the transmission of electrons and ions. At the same time, due to its unique two-dimensional structure, high specific surface area and good conductivity, the nano copper oxide sheet has excellent mechanical properties, optical properties and electrical properties, and can be widely used in important fields such as catalysis, energy storage, sensors, environmental management, electronic devices and biomedicine.

[0051] The following will Figure 1 The preparation method of the nano copper oxide sheet shown in the figure is further explained and illustrated. Specifically:

[0052] In step S110, under the action of magnetic stirring, the copper salt is configured as a copper precursor aqueous solution containing a surfactant, and the base is configured as an alkaline solution.

[0053] Specifically, the copper salts recorded herein may include but are not limited to copper chloride, copper acetate, copper sulfate and copper nitrate, etc.; the concentration of the copper precursor aqueous solution containing surfactant recorded herein needs to be less than or equal to 70 g / L, which is the total concentration of the surfactant and the copper salt; at the same time, the surfactant recorded herein may include but is not limited to polyethylene glycol (PEG), polyvinyl pyrrolidone (PVP), hexadecyltrimethylammonium bromide (CTAB), hexadecyltrimethylammonium chloride (CTAC), sodium dodecylbenzene sulfonate (SDBS), polydiallyldimethylammonium chloride (PDDA) or polysorbate (Tween, Tween), etc.; further, the alkaline aqueous solution recorded herein may include but is not limited to sodium hydroxide, sodium carbonate, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate and ammonia water, etc.; and the concentration of the alkaline aqueous solution needs to be less than or equal to 100 g / L; the pH value of the alkaline hydrated solution is between 7 and 9, which is in a weakly alkaline state.

[0054] It should be noted that the reason why surfactants need to be added here is that surfactants can be adsorbed on specific crystal planes in a selective manner, inhibiting their growth in the thickness direction, allowing the material to expand in the lateral direction, thereby forming a sheet structure; at the same time, different surfactant types and concentrations will affect the thickness, surface smoothness and lateral size of the sheet structure, and directional control of the sheet structure can be achieved by precisely controlling the amount of surfactant; further, due to the high pH value, the metal ions in the solution can be quickly saturated, the nucleation rate can be increased, and a larger nucleation density can be formed; therefore, the pH value of the alkaline mixed solution is controlled between 7 and 9 to make it in a weakly alkaline state, so that the material can grow evenly distributed along the crystal plane, so that multiple nucleation points are gradually connected into sheets; further, the concentration of the copper salt aqueous solution containing surfactants and the type and concentration of the screened alkali meet the needs of nucleation growth and morphology size regulation of the product nano-copper oxide.

[0055] In step S120, a high-frequency electronic oscillation device is used to convert the copper precursor aqueous solution containing a surfactant into a copper micro-nano aerosol containing a surfactant, and to convert the alkaline solution into an alkali-containing micro-nano aerosol.

[0056] Specifically, the oscillation frequency of the high-frequency electronic oscillation device recorded here needs to be less than or equal to 4 MHz; at the same time, the obtained copper micro-nano aerosol containing surfactant is composed of ultra-fine nano-droplets with an average size of less than or equal to 10 μm; further, the obtained alkali-containing micro-nano aerosol is composed of ultra-fine nano-droplets with an average size of less than or equal to 10 μm. It should be added here that the reason why the copper micro-nano aerosol containing surfactant and the micro-nano aerosol containing alkali need to be prepared by a high-frequency electronic oscillation device is that the high-frequency electronic oscillation device is conducive to converting the copper salt aqueous solution and the alkaline solution containing surfactant into an aerosol form that is easier to diffuse and has a smaller average particle size and a higher specific surface area, effectively strengthening the transmission and reaction kinetic conditions of the copper source and alkali during the reaction process, and at the same time constructing a large number of micro-nano reaction areas, thereby inhibiting the agglomeration and ripening process of nanoparticles of copper compounds, which helps to achieve control of the product morphology and size.

[0057] In step S130, a copper micro-nano aerosol containing a surfactant and a micro-nano aerosol containing an alkali are subjected to a gas phase confined micro-area mixing pre-reaction to obtain a copper-alkali mixed solution, and the copper-alkali mixed solution is transferred to a polytetrafluoroethylene reactor for a hydrothermal reaction to obtain a nanoparticle solution containing copper compounds.

[0058] Specifically, the gas phase confined micro-region mixing pre-reaction recorded here is carried out at room temperature; at the same time, in the process of gas phase confined micro-region mixing pre-reaction, micro-region mixing is required in the gas phase confinement of less than 20 μm; and in the process of transferring the copper-alkali mixed solution to a polytetrafluoroethylene reactor for hydrothermal reaction to obtain a nanoparticle solution of copper compounds, the required hydrothermal reaction temperature is 100 ℃~200 ℃. Further, it is also necessary to add that in the process of generating copper-alkali mixing, the copper micro-nano aerosol containing surfactant can also be replaced with a copper-containing aqueous solution of the same composition; of course, the alkali-containing micro-nano aerosol can also be replaced with an alkaline solution of the same composition; however, the nanoparticles of the copper-containing compound obtained after the corresponding replacement have irregular morphology and large size; further, the duration of the hydrothermal reaction recorded here is 1~10 h, and in the process of transferring the copper-mixed alkali solution to a polytetrafluoroethylene reactor for hydrothermal reaction, the pressure in the polytetrafluoroethylene reactor is between 3~10 MPa.

[0059] It should be further explained here that the reason why the temperature of the hydrothermal reaction needs to be controlled at 100 ℃ ~ 200 ℃ for quality inspection is because the reaction temperature has a significant effect on the growth rate and morphology of the crystal. At higher temperatures, the growth rate of the material is accelerated, and it is easier to grow uniformly along a specific crystal plane, thus forming a thin sheet structure; and, appropriately extending the reaction time can allow the thin sheet to grow fully and obtain a larger area of ​​the sheet structure; too short a reaction time may result in an incomplete sheet morphology, while too long a reaction time may cause the sheet structure to overlap or become thicker.

[0060] In step S140, the nanoparticle solution containing the copper compound is subjected to solid-liquid separation, washing, drying and calcining to obtain the nano copper oxide sheet.

[0061] Specifically, in the process of solid-liquid separation of the nanoparticle solution containing copper compounds, the solid-liquid separation method used is centrifugal separation and / or suction filtration separation; in the process of washing the separated nanoparticles containing copper compounds, the washing solution used is water and / or ethanol; in the process of drying the washed nanoparticles containing copper compounds, the drying method used is thermal drying and / or freeze drying; in the process of calcining the dried nanoparticles containing copper compounds, the calcination temperature used is 200 ℃~500 ℃, the atmosphere used is air; the calcination time is 2h. At the same time, in the nano copper oxide flakes obtained based on this method, the size of a single nano copper oxide flake is 1~4 μm, the average size is 2 μm, and the thickness of a single sheet is about 30~60 nm.

[0062] Furthermore, after obtaining the nano copper oxide sheets, the prepared nano copper oxide sheets can also be used to prepare catalysts, energy storage materials, sensors, environmental management materials, electronic devices, biomedical materials and other materials, thereby achieving the purpose of reducing the preparation cost of various materials.

[0063] At this point, the method for preparing the nano copper oxide sheet described in the exemplary embodiment of the present disclosure has been fully realized. Based on the above-described content, it can be known that the method for preparing the nano copper oxide sheet described in the exemplary embodiment of the present disclosure has at least the following advantages:

[0064] On the one hand, the exemplary embodiments of the present disclosure use common water-soluble copper precursors as copper sources, low-cost water-soluble organic matter as surfactants, and ordinary alkaline solutions as control agents for regulating crystal nucleation and growth. The copper source and alkali are converted into micro-nano aerosol forms for reaction, three-dimensional spatial confined micro-region reaction conditions are constructed, and material transport and reaction kinetic conditions are controlled, thereby achieving controllable preparation of the morphology of copper oxide nanosheets. On the other hand, the exemplary embodiments of the present disclosure obtain micro-nano aerosols by subjecting water-soluble copper source aqueous solutions and alkaline solutions to high-frequency electronic oscillations, which not only greatly improves the transmission and diffusion rate of the copper source during the mixing process, but also greatly improves the specific surface area of ​​droplets in the aerosol, effectively enhancing the transmission and diffusion of copper salts and the regulation of copper compounds by alkaline aqueous solutions during crystal growth. It is conducive to controlling the morphology and size of the product; on the other hand, the exemplary embodiment of the present disclosure is conducive to improving the dispersibility of the product through the transmission of micro-nano aerosols; then the hydrothermal synthesis method is used to react, and the reaction kinetics of crystal growth are optimized by changing the reaction temperature, pressure, time and pH, so that the copper compound grows laterally, thereby achieving precise control of the morphology and size of the product copper-containing compound nanoparticles, and the morphology, size, uniformity and dispersibility of the prepared copper oxide and copper nanosheets are significantly better than those of traditional preparation methods; further, the exemplary embodiment of the present disclosure achieves precise control of the crystal structure, morphology and size of copper oxide and copper by controlling the solid-liquid separation method, washing method, drying conditions, and calcination and reduction pathways of the copper-containing compound nanoparticles, which is conducive to obtaining a sheet-like nanostructure.

[0065] Hereinafter, the preparation method of the nano copper oxide sheet described in the exemplary embodiment of the present disclosure will be further explained and illustrated in combination with specific embodiments. Specifically:

[0066] Embodiment 1: The method for preparing the nano copper oxide sheet described in the exemplary embodiment of the present disclosure may include the following steps:

[0067] Step 1: prepare copper acetate, polyethylene glycol and sodium carbonate into a copper salt aqueous solution containing a surfactant and an alkaline aqueous solution respectively; the concentration of the copper salt aqueous solution containing a surfactant is 70 g / L, wherein the mass fraction of polyethylene glycol is 1%, the concentration of the alkaline aqueous solution is 100 g / L, and the pH value of the alkaline mixed solution is between 7 and 9, which is in a weakly alkaline state;

[0068] Step 2: using a high-frequency electronic oscillation device with a frequency of 4 MHz to convert the copper salt aqueous solution containing a surfactant and the alkaline aqueous solution prepared in step 1 into a copper micro-nano aerosol containing a surfactant and an alkali-containing micro-nano aerosol, respectively; the copper micro-nano aerosol containing a surfactant and the alkali-containing micro-nano aerosol are both formed by ultrafine nano droplets with an average particle size of less than 10 μm;

[0069] Step 3, the alkali-containing micro-nano aerosol and the copper-containing micro-nano aerosol obtained in step 2 are subjected to a gas phase confined micro-area mixing pre-reaction, and then the mixed solution is quickly transferred to a polytetrafluoroethylene reactor for a hydrothermal reaction at a reaction temperature of 150 ° C, a reaction time of 2 h, and a pressure in the reactor of 3 to 10 MPa. After cooling to room temperature, a nanoparticle solution containing a copper compound is collected;

[0070] Step 4: centrifuge the copper compound nanoparticle solution collected in step 3, wash with 18.2 MΩ ultrapure water, dry in an oven at 70°C, and then calcine at 300°C~400°C in an air atmosphere for 2 hours to obtain a flaky nano copper oxide powder; wherein the obtained flaky nano copper oxide (also known as nano copper oxide sheet) has a length of about 1~4 μm, an average size of about 2 μm, and a thickness of a single sheet of about 30~60 nm. The SEM image of the copper oxide nanosheet obtained in this way can be referred to Figure 2 As shown, the size distribution diagram of the copper oxide nanosheets obtained based on this method can be referred to Figure 3 As shown, the XRD pattern of the copper oxide nanosheets obtained in this way can be referred to Figure 4 shown.

[0071] Furthermore, the copper salt aqueous solution in step 1 of this embodiment can also be replaced by copper sulfate, copper nitrate or copper chloride; the surfactant can also be replaced by PVP, CTAB, CTAC, SDBS, PDDA or Tween; the alkaline aqueous solution can also be replaced by sodium hydroxide, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate or ammonia water.

[0072] Furthermore, if the copper oxide nanosheets are subjected to a reduction reaction at a temperature of 150°C to 200°C, flaky nano-copper powder can be obtained; wherein, during the reduction reaction, the atmosphere used is hydrogen.

[0073] Embodiment 2: The method for preparing the nano copper oxide sheet described in the exemplary embodiment of the present disclosure may include the following steps:

[0074] Step 1: prepare copper acetate, polyethylene glycol and sodium carbonate into a copper salt aqueous solution containing a surfactant and an alkaline aqueous solution respectively; the concentration of the copper salt aqueous solution containing a surfactant is 70 g / L, wherein the mass fraction of polyethylene glycol is 1%, the concentration of the alkaline aqueous solution is 100 g / L, and the pH value of the alkaline mixed solution is between 7 and 9, which is in a weakly alkaline state;

[0075] Step 2: using a high-frequency electronic oscillation device with a frequency of 4 MHz to convert the copper salt aqueous solution containing a surfactant and the alkaline aqueous solution prepared in step 1 into a copper micro-nano aerosol containing a surfactant and an alkali-containing micro-nano aerosol, respectively; the copper micro-nano aerosol containing a surfactant and the alkali-containing micro-nano aerosol are both formed by ultrafine nano droplets with an average particle size of less than 10 μm;

[0076] Step 3, the alkali-containing micro-nano aerosol and the copper-containing micro-nano aerosol obtained in step 2 are subjected to a gas phase confined micro-area mixing pre-reaction, and then the mixed solution is quickly transferred to a polytetrafluoroethylene reactor for a hydrothermal reaction at a reaction temperature of 150 ° C, a reaction time of 1 h, and a pressure in the reactor of 3 to 10 MPa. After cooling to room temperature, a nanoparticle solution containing a copper compound is collected;

[0077] Step 4: centrifuge the copper compound nanoparticle solution collected in step 3, wash with 18.2 MΩ ultrapure water, and heat dry in an oven at 70 ° C, and then calcine at 300 ° C ~ 400 ° C in an air atmosphere for 2 hours to obtain a flaky nano copper oxide powder. The length of the obtained flaky nano copper oxide is about 0.5 ~ 2 μm, the average size is about 1 μm, and the thickness of a single sheet is about 10 ~ 30 nm. It should be supplemented here that the SEM image of the copper oxide nanosheets obtained in this way, the size distribution diagram of the copper oxide nanosheets, and the XRD diagram of the copper oxide nanosheets are similar to the SEM image of the copper oxide nanosheets obtained in Example 1, the size distribution diagram of the copper oxide nanosheets, and the XRD diagram of the copper oxide nanosheets, and they are not listed one by one here.

[0078] Furthermore, the copper salt aqueous solution in step 1 of this embodiment can also be replaced by copper sulfate, copper nitrate or copper chloride; the surfactant can also be replaced by PVP, CTAB, CTAC, SDBS, PDDA or Tween; the alkaline aqueous solution can also be replaced by sodium hydroxide, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate or ammonia water.

[0079] Furthermore, if the copper oxide nanosheets are subjected to a reduction reaction at a temperature of 150°C to 200°C, flaky nano-copper powder can be obtained; wherein, during the reduction reaction, the atmosphere used is hydrogen.

[0080] Embodiment 3: The method for preparing the nano copper oxide sheet described in the exemplary embodiment of the present disclosure may include the following steps:

[0081] Step 1: prepare copper acetate, polyethylene glycol and sodium carbonate into a copper salt aqueous solution containing a surfactant and an alkaline aqueous solution respectively; the concentration of the copper salt aqueous solution containing a surfactant is 70 g / L, wherein the mass fraction of polyethylene glycol is 1%, the concentration of the alkaline aqueous solution is 100 g / L, and the pH value of the alkaline mixed solution is between 7 and 9, which is in a weakly alkaline state;

[0082] Step 2: using a high-frequency electronic oscillation device with a frequency of 4 MHz to convert the copper salt aqueous solution containing a surfactant and the alkaline aqueous solution prepared in step 1 into a copper micro-nano aerosol containing a surfactant and an alkali-containing micro-nano aerosol, respectively; the copper micro-nano aerosol containing a surfactant and the alkali-containing micro-nano aerosol are both formed by ultrafine nano droplets with an average particle size of less than 10 μm;

[0083] Step 3, the alkali-containing micro-nano aerosol and the copper-containing micro-nano aerosol obtained in step 2 are subjected to a gas phase confined micro-area mixing pre-reaction, and then the mixed solution is quickly transferred to a polytetrafluoroethylene reactor for a hydrothermal reaction at a reaction temperature of 150 ° C, a reaction time of 8 h, and a pressure in the reactor of 3 to 10 MPa. After cooling to room temperature, a nanoparticle solution containing a copper compound is collected;

[0084] Step 4: centrifuge the copper compound nanoparticle solution collected in step 3, wash with 18.2 MΩ ultrapure water, and heat dry in an oven at 70 ° C, and then calcine at 300 ° C ~ 400 ° C in an air atmosphere for 2 hours to obtain a flaky nano copper oxide powder. The length of the obtained flaky nano copper oxide is about 2 ~ 6 μm, the average size is about 4 μm, and the thickness of a single sheet is about 40 ~ 100 nm. It should be noted here that the SEM image of the copper oxide nanosheets obtained in this way, the size distribution diagram of the copper oxide nanosheets, and the XRD diagram of the copper oxide nanosheets are similar to the SEM image of the copper oxide nanosheets obtained in Example 1, the size distribution diagram of the copper oxide nanosheets, and the XRD diagram of the copper oxide nanosheets, and are not listed one by one here.

[0085] Furthermore, the copper salt aqueous solution in step 1 of this embodiment can also be replaced by copper sulfate, copper nitrate or copper chloride; the surfactant can also be replaced by PVP, CTAB, CTAC, SDBS, PDDA or Tween; the alkaline aqueous solution can also be replaced by sodium hydroxide, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate or ammonia water.

[0086] Comparative Example 1: The method for preparing copper oxide nanosheets described in this embodiment comprises the following steps:

[0087] Step 1: prepare copper acetate, polyethylene glycol and sodium carbonate into a copper salt aqueous solution containing a surfactant and an alkaline aqueous solution respectively; the concentration of the copper salt aqueous solution containing a surfactant is 70 g / L, wherein the mass fraction of polyethylene glycol is 5%, the concentration of the alkaline aqueous solution is 100 g / L, and the pH value of the alkaline mixed solution is between 7 and 9, which is in a weakly alkaline state;

[0088] Step 2: using a high-frequency electronic oscillation device with a frequency of 4 MHz to convert the copper salt aqueous solution containing a surfactant and the alkaline aqueous solution prepared in step 1 into a copper micro-nano aerosol containing a surfactant and an alkali-containing micro-nano aerosol, respectively; the copper micro-nano aerosol containing a surfactant and the alkali-containing micro-nano aerosol are both formed by ultrafine nano droplets with an average particle size of less than 10 μm;

[0089] Step 3, the alkali-containing micro-nano aerosol and the copper-containing micro-nano aerosol obtained in step 2 are subjected to a gas phase confined micro-area mixing pre-reaction, and then the mixed solution is quickly transferred to a polytetrafluoroethylene reactor for a hydrothermal reaction at a reaction temperature of 150 ° C, a reaction time of 2 h, and a pressure in the reactor of 3 to 10 MPa. After cooling to room temperature, a nanoparticle solution containing a copper compound is collected;

[0090] Step 4, centrifuge the copper compound nanoparticle solution collected in step 3, wash with 18.2 MΩ ultrapure water, and heat dry in an oven at 70°C, then calcine at 300°C~400°C in an air atmosphere to obtain flaky nano copper oxide powder; finally, reduce it at 150°C~200°C in a hydrogen atmosphere to obtain flaky nano copper powder. When the amount of PEG is increased, the higher concentration of surfactant will affect the thickness, surface smoothness and lateral size of the flaky structure, and the size of the obtained flaky nano copper oxide becomes slightly smaller and thinner, with a length of about 1~3 μm, an average size of about 1.5 μm, and a thickness of a single sheet of about 20~50 nm. Among them, the SEM image of the copper oxide nanosheets obtained based on this method can be referred to. Figure 5 shown.

[0091] The copper salt aqueous solution in step 1 of this embodiment can also be replaced by copper sulfate, copper nitrate or copper chloride; the surfactant can also be replaced by PVP, CTAB, CTAC, SDBS, PDDA or Tween; the alkaline aqueous solution can also be replaced by sodium hydroxide, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate or ammonia water.

[0092] Comparative Example 2: The method for preparing copper oxide nanosheets described in this embodiment comprises the following steps:

[0093] Step 1: prepare copper acetate, polyethylene glycol, sodium carbonate and sodium hydroxide into a copper salt aqueous solution containing a surfactant and an alkaline mixed aqueous solution respectively; the concentration of the copper salt aqueous solution containing a surfactant is 70 g / L, wherein the mass fraction of polyethylene glycol is 1%, the concentration of the alkaline mixed aqueous solution is 180 g / L, and the pH value of the alkaline mixed solution is between 12 and 14, which is in a weakly alkaline state;

[0094] Step 2: using a high-frequency electronic oscillation device with a frequency of 4 MHz to convert the copper salt aqueous solution containing a surfactant and the alkaline mixed aqueous solution prepared in step 1 into a copper micro-nano aerosol containing a surfactant and a micro-nano aerosol containing a mixed alkali, respectively; the copper micro-nano aerosol containing a surfactant and the micro-nano aerosol containing a mixed alkali are both formed by ultrafine nano droplets with an average particle size of less than 10 μm;

[0095] Step 3, subjecting the mixed alkali-containing micro-nano aerosol and the copper-containing micro-nano aerosol obtained in step 2 to a gas phase confined micro-area mixing pre-reaction, and then rapidly transferring the mixed solution to a polytetrafluoroethylene reactor for a hydrothermal reaction at a reaction temperature of 150 ° C. for a reaction time of 2 h. The pressure in the reactor is between 3 and 10 MPa. After cooling to room temperature, a nanoparticle solution containing a copper compound is collected;

[0096] Step four, centrifuge the copper compound nanoparticle solution collected in step three, wash with 18.2 MΩ ultrapure water, dry in an oven at 70°C, and then calcine at 300°C~400°C in an air atmosphere to obtain flaky nano copper oxide powder; finally, reduce it at 150°C~200°C in a hydrogen atmosphere to obtain flaky nano copper powder. When the pH value in the solution is further increased, the metal ions in the solution quickly reach a saturation concentration, the nucleation rate is rapidly increased, and the material is promoted to grow longitudinally along the crystal plane, so that multiple nucleation sites are gradually connected into sheets, while the lateral direction grows slower, gradually forming a narrow sheet structure. The length is about 1~4 μm, the average size is about 2 μm, and the thickness of a single sheet is about 20~40 nm. Among them, the SEM image of the copper oxide nanosheet obtained based on this method can be referred to. Figure 6 shown.

[0097] The copper salt aqueous solution in step 1 of this embodiment can also be replaced by copper sulfate, copper nitrate or copper chloride; the surfactant can also be replaced by PVP, CTAB, CTAC, SDBS, PDDA or Tween; the alkaline mixed aqueous solution can also be replaced by a mixed solution of sodium hydroxide, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate or ammonia water.

[0098] In addition, the above-mentioned figures are only schematic illustrations of the processes included in the method according to the exemplary embodiments of the present disclosure, and are not intended to be limiting. It is easy to understand that the processes shown in the above-mentioned figures do not indicate or limit the time sequence of these processes. In addition, it is also easy to understand that these processes can be performed synchronously or asynchronously, for example, in multiple modules.

[0099] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

[0100] It should be understood that the present disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims. The description and embodiments are to be regarded as exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

Claims

1. A method for preparing a nano copper oxide sheet, characterized in that: The method comprises the following steps: Step 1: Under the action of magnetic stirring, the copper salt is configured as a copper precursor aqueous solution containing a surfactant, and the base is configured as an alkaline aqueous solution; Step 2: using a high-frequency electronic oscillation device to convert the copper precursor aqueous solution containing a surfactant into a copper micro-nano aerosol containing a surfactant, and to convert the alkaline aqueous solution into an alkali-containing micro-nano aerosol; Step 3, performing a gas phase confined micro-area mixing pre-reaction on the copper micro-nano aerosol containing a surfactant and the micro-nano aerosol containing an alkali to obtain a copper-alkali mixed solution, and transferring the copper-alkali mixed solution to a polytetrafluoroethylene reactor for hydrothermal reaction to obtain a nanoparticle solution containing a copper compound; Step 4: performing solid-liquid separation, washing, drying and calcining on the nanoparticle solution containing the copper compound to obtain the nano copper oxide sheet.

2. The method for preparing the nano copper oxide sheet according to claim 1, characterized in that: The copper salt includes at least one of copper chloride, copper acetate, copper sulfate and copper nitrate; The concentration of the copper precursor aqueous solution containing the surfactant is less than or equal to 70 g / L; wherein the concentration is the total concentration of the surfactant and the copper salt.

3. The method for preparing nano copper oxide sheets according to claim 1, characterized in that: The surfactant includes at least one of polyethylene glycol, polyvinyl pyrrolidone, cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, sodium dodecylbenzene sulfonate, polydiallyldimethylammonium chloride and polysorbate.

4. The method for preparing nano copper oxide sheets according to claim 1, characterized in that: The alkaline aqueous solution is at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate and ammonia water; The concentration of the alkaline aqueous solution is less than or equal to 100 g / L; The pH value of the alkaline aqueous solution is between 7 and 9, which is in a weakly alkaline state.

5. The method for preparing nano copper oxide sheets according to claim 1, characterized in that: The oscillation frequency of the high-frequency electronic oscillation device is less than or equal to 4 MHz; The copper micro-nano aerosol containing surfactant is composed of ultra-fine nano-droplets with an average size of less than or equal to 10 μm; The alkali-containing micro-nano aerosol is composed of ultra-fine nano-liquid droplets with an average size of less than or equal to 10 μm.

6. The method for preparing nano copper oxide sheets according to claim 1, characterized in that: The gas phase confined micro-region mixing pre-reaction is carried out at room temperature; In the process of gas phase confinement micro-region mixing pre-reaction, micro-region mixing needs to be carried out in the gas phase confinement less than 20 μm.

7. The method for preparing nano copper oxide sheets according to claim 1, characterized in that: In the process of transferring the copper-alkali mixed solution to a polytetrafluoroethylene reactor for hydrothermal reaction to obtain a nanoparticle solution containing copper compounds, the temperature of the hydrothermal reaction is 100° C. to 200° C., the pressure in the polytetrafluoroethylene reactor is between 3 and 10 MPa, and the hydrothermal reaction time is 1 to 10 hours.

8. The method for preparing nano copper oxide sheets according to claim 1, characterized in that: In the process of solid-liquid separation of the nanoparticle solution containing the copper compound, the solid-liquid separation method used is centrifugal separation and / or suction filtration separation; In the process of washing the separated nanoparticles containing copper compounds, the washing solution used is water and / or ethanol; In the process of drying the washed copper compound-containing nanoparticles, the drying method used is thermal drying and / or freeze drying; In the process of calcining the dried copper compound-containing nanoparticles, the calcination temperature used is 200°C~500°C, the atmosphere used is air, and the calcination time is 2h.

9. The method for preparing nano copper oxide sheets according to claim 1, characterized in that: In the obtained nano copper oxide flakes, the size of a single nano copper oxide flake is 1-4 μm, the average size is 2 μm, and the thickness of a single sheet is 30-60 nm.

10. The method for preparing the nano copper oxide sheet according to any one of claims 1 to 9, characterized in that: The prepared nano copper oxide sheet is used to prepare at least one of the following materials: Catalysts, energy storage materials, environmental management materials, electronic devices and biomedical materials.

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