Submicron cuprous oxide cubes and method for making same
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- YUNNAN PRECIOUS METALS LAB CO LTD
- Filing Date
- 2026-05-14
- Publication Date
- 2026-06-23
AI Technical Summary
Existing technologies make it difficult to prepare high-purity, well-defined cuprous oxide micro/nanomaterials, especially cubic structures, in a green and convenient manner. They also suffer from problems such as high equipment costs, high energy consumption, difficulty in precisely controlling product morphology, and environmental unfriendliness.
A liquid-phase chemical reduction method was adopted, in which water-soluble nonionic cellulose derivatives were used as morphology control agents and ascorbic acid reducing agents in a highly alkaline environment to synergistically regulate the crystal face growth of cuprous oxide and form submicron cuprous oxide cubes.
It achieves precise control over the morphology and size of the product, with high product purity, is environmentally friendly, has a simple process, and can be mass-produced, making it suitable for industrial applications.
Smart Images
Figure CN122254545A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of micro and nanomaterials technology, and in particular to a submicron-sized cuprous oxide cube and its preparation method. Background Technology
[0002] Cuprous oxide (Cu2O), as a typical p-type semiconductor, possesses excellent optical, electrical, catalytic, and biocompatibility properties, and has broad application prospects in fields such as photocatalytic degradation of pollutants, photoelectric conversion devices, chemical sensors, antibacterial materials, and lithium-ion battery electrode materials.
[0003] The properties of cuprous oxide micro / nanomaterials are closely related to their morphology, size, and crystal form. Among them, the cubic structure has become a research hotspot in this field due to its highly symmetrical crystal plane arrangement, excellent electron transport efficiency, and specific surface active sites. Currently, the preparation methods of cuprous oxide micro / nanomaterials are mainly divided into physical methods and chemical methods. Physical methods include vacuum evaporation and sputtering deposition, while chemical methods include liquid-phase reduction, hydrothermal methods, and sol-gel methods.
[0004] While physical methods can prepare high-purity cuprous oxide materials, they suffer from drawbacks such as high equipment costs, high energy consumption, difficulty in precisely controlling product morphology, and challenges in large-scale production, limiting their widespread application. Traditional liquid-phase chemical methods, due to their simple operation, low cost, and mild reaction conditions, have become the mainstream technology for the large-scale preparation of micro- and nano-sized cuprous oxide. However, chemical methods suffer from poor reaction system compatibility, and some methods require harsh conditions such as high temperature and pressure, resulting in high process complexity and safety risks, and may also lead to crystal defects in the product. Furthermore, chemical methods are not environmentally friendly enough, with some schemes using toxic and harmful reagents, easily causing environmental pollution and contradicting the trend of green chemical development. Moreover, chemical methods typically use concentrated alkali to control the crystal form of cuprous oxide, but the control mechanism of concentrated alkali is not yet clear, leading to poor product reproducibility.
[0005] For example, some related technologies use formaldehyde as a reducing agent to prepare cuprous oxide. Formaldehyde is toxic, volatile, and irritates the human respiratory tract and skin. Its strong reducing properties also lead to excessively fast reaction rates and severe product aggregation. Other technologies use hydrazine hydrate as a reducing agent to prepare cuprous oxide nanocrystal cubes. Hydrazine hydrate is highly toxic and carcinogenic, posing a significant threat to human health and the environment. Furthermore, it requires strict control of volume ratios, making the process difficult to operate and resulting in poor reproducibility. Still other technologies use complex surfactants (such as the cationic surfactant cetyltrimethylammonium bromide) as morphology control agents, combined with ethylenediaminetetraacetic acid (EDTA) and CTAB as composite additives to prepare cuprous oxide. While this can achieve a cubic structure, the reaction conditions are harsh, and EDTA is biotoxic, while CTAB has poor biodegradability and easily remains in soil and water, failing to meet the requirements of green and environmentally friendly production.
[0006] In summary, developing a method for the precise preparation of cubic cuprous oxide micro / nanomaterials based on green reagents and simple operation is a technical problem that urgently needs to be solved in this field. Summary of the Invention
[0007] In view of this, the present invention provides a submicron-sized cuprous oxide cube and its preparation method. The present invention prepares submicron-sized cuprous oxide cubes based on a liquid-phase chemical reduction method. Through the synergistic regulation of morphology control agents and a concentrated alkaline environment, the precise construction of the cube structure is achieved, resulting in products with uniform morphology and high purity. Furthermore, the reagents used are environmentally friendly, and the process is simple and can be mass-produced, filling the gap in the controllable synthesis of high-purity cubic cuprous oxide in existing technologies.
[0008] To achieve the above-mentioned objectives, the present invention provides the following technical solution: A method for preparing submicron-sized cuprous oxide cubes includes the following steps: Sodium hydroxide solution was added to the copper precursor compound solution to adjust the pH of the system to ≥10. Then, morphology control agent solution and reducing agent solution were added to carry out redox reaction to obtain submicron cuprous oxide cubes. The morphology control agent is a water-soluble nonionic cellulose derivative; the reducing agent is an ascorbic acid-based reducing agent.
[0009] Preferably, the water-soluble nonionic cellulose derivative includes one or more of hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethyl methyl cellulose, and hydroxypropyl methyl cellulose; the viscosity of the hydroxyethyl cellulose is 1000~1500 mPa·s, the viscosity of the hydroxypropyl cellulose is 1000~4000 mPa·s, the viscosity of the hydroxyethyl methyl cellulose is 12000~17000 mPa·s, and the viscosity of the hydroxypropyl methyl cellulose is 400~4000 mPa·s; The ascorbic acid reducing agents include one or more of ascorbic acid, ascorbate, and isoflavone.
[0010] Preferably, the copper precursor compound is at least one of copper nitrate and copper chloride.
[0011] Preferably, the concentration of the copper precursor compound solution is 0.0125~0.1 mol / L; the concentration of the morphology control agent solution is 0.002~0.02 g / mL; the concentration of the reducing agent solution is 0.05~0.2 mol / L; and the volume ratio of the morphology control agent solution, the copper precursor compound solution, and the reducing agent solution is 0.5~1.5:0.5~1.5:0.5~1.5.
[0012] Preferably, the concentration of the sodium hydroxide solution is 1.5~2.5 mol / L.
[0013] Preferably, the reducing agent solution is added after the morphology control agent solution has been added; the addition rate of the reducing agent solution is 3~4 mL / min.
[0014] Preferably, the redox reaction is carried out at a temperature of 0~40℃ for a time of 0.5~2 h.
[0015] Preferably, after the redox reaction is completed, the product liquid is centrifuged, and the resulting solid product is washed and dried to obtain the submicron-sized cuprous oxide cubes.
[0016] The present invention also provides submicron-sized cuprous oxide cubes prepared by the preparation method described above.
[0017] This invention provides a method for preparing submicron-sized cuprous oxide cubes, comprising the following steps: A sodium hydroxide solution was added to a copper precursor compound solution to adjust the pH of the system to ≥10. Then, a morphology control agent solution and a reducing agent solution were added to carry out a redox reaction, yielding submicron-sized cuprous oxide cubes. The morphology control agent was a water-soluble nonionic cellulose derivative; the reducing agent was an ascorbic acid-based reducing agent. The mechanism involved in this invention includes: Cuprous oxide crystals have a cubic cuprite structure. Its (100) crystal plane is a thermodynamically stable plane with low surface energy and negative charge, while its (111) crystal plane is a easily tunable plane with high surface energy and positive charge. This forms the basis for the directional formation of the cubic structure. In a concentrated alkaline environment (pH≥10), the OH groups of sodium hydroxide... - Cu dissociated from copper precursor 2+ They combine to form [Cu(OH)4] 2- Stabilized complexes can reduce free Cu 2+The concentration avoids excessively rapid reduction rates leading to disordered nucleation, while also suppressing the formation of CuO impurities and modifying the charge distribution on the crystal planes, amplifying the charge difference between the (100) and (111) crystal planes, thus creating conditions for the selective adsorption of morphology control agents. This invention selects water-soluble nonionic cellulose derivatives as morphology control agents. The molecules are rich in hydroxyl substituents, and the hydroxyl groups (-OH) tend to selectively adsorb on the Cu2O (111) crystal plane. They can form hydrogen bonds with the (111) crystal plane atoms through -OH, moderately inhibiting the growth of this crystal plane, without forming a dense coating layer that completely blocks the growth of the crystal plane. For the negatively charged (100) crystal plane, only very weak adsorption occurs, which does not hinder its smooth extension at all. Furthermore, molecular adsorption can further reduce the surface energy of the (100) crystal plane and enhance its thermodynamic stability. Moreover, this type of long-chain molecular structure can exert a good steric hindrance effect, effectively avoiding particle agglomeration, and ultimately benefiting the submicron size (100 nm~1 Synthesis of cubic cuprous oxide (µm); finally, by adding a reducing agent, [Cu(OH)4] can be gradually reduced. 2- Reduced to Cu + To avoid crystal distortion due to excessive reduction rate, a pure phase, regular cubic cuprous oxide micro / nano structure surrounded by six (100) crystal planes is finally formed.
[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. Precise and controllable morphology and size: Through the synergistic regulation of a concentrated alkaline environment (pH≥10) and a water-soluble nonionic cellulose derivative morphology control agent, pure-phase submicron cuprous oxide cubes were successfully prepared. The product has a regular morphology, clear edges and corners, no other impurity phases, and a size distribution concentrated in 100 nm~1 μm with excellent uniformity, which solves the problems of irregular morphology and wide size dispersion in traditional methods.
[0019] 2. High product purity: The concentrated alkaline environment effectively inhibits the conversion of cuprous oxide to copper oxide. Combined with the mild reducing properties of the green reducing agent, there are no impurity peaks in the XRD pattern of the product, indicating high purity of cuprous oxide.
[0020] 3. Green, environmentally friendly and highly safe: This invention uses green and non-toxic ascorbic acid reducing agents, combined with water-soluble non-ionic morphology control agents with excellent biocompatibility, and uses water as the reaction medium. The reaction process is environmentally friendly and leaves no toxic or harmful reagent residues. Furthermore, the method provided by this invention has mild reaction conditions, does not require high temperature and high pressure, is safe to operate, and has strong process compatibility.
[0021] 4. Simple process and scalable: The reaction equipment used in this invention is conventional laboratory or industrial equipment (water bath, peristaltic pump, centrifuge, etc.). The operation steps are simple, and the reaction parameters (concentration, volume ratio, temperature, time) are highly controllable and reproducible, making it suitable for large-scale industrial production.
[0022] 5. Great application potential: The submicron-sized cuprous oxide cubes prepared by this invention have a regular crystal structure and excellent electron transport performance, which have significant performance advantages in photocatalysis, sensors, optoelectronic devices and other fields, thus broadening the application scenarios of cuprous oxide materials. Attached Figure Description
[0023] Figure 1 XRD pattern of submicron cuprous oxide cubes prepared in Example 1; Figure 2 The images show SEM images of the submicron-sized cuprous oxide cubes prepared in Example 1 at different magnifications. The left image is a high-magnification SEM image, and the right image is a low-magnification SEM image. Figure 3 The images show SEM images of the submicron-sized cuprous oxide cubes prepared in Example 2 at different magnifications. The left image is a high-magnification SEM image, and the right image is a low-magnification SEM image. Figure 4 The images show SEM images of the submicron-sized cuprous oxide cubes prepared in Example 3 at different magnifications. The left image is a high-magnification SEM image, and the right image is a low-magnification SEM image. Figure 5 The images show SEM images of the submicron-sized cuprous oxide cubes prepared in Example 4 at different magnifications. The left image is a high-magnification SEM image, and the right image is a low-magnification SEM image. Figure 6 The images are scanning electron microscope (SEM) images of cuprous oxide prepared in Comparative Example 1 at different magnifications. The left image is the SEM image at high magnification, and the right image is the SEM image at low magnification. Figure 7 The images show SEM images of cuprous oxide prepared in Comparative Example 2 at different magnifications. The left image is the SEM image at high magnification, and the right image is the SEM image at low magnification. Figure 8 The images show SEM images of cuprous oxide prepared in Comparative Example 3 at different magnifications. The left image is the SEM image at high magnification, and the right image is the SEM image at low magnification. Figure 9 The images show SEM images of cuprous oxide prepared in Comparative Example 4 at different magnifications. The left image is the SEM image at high magnification, and the right image is the SEM image at low magnification. Figure 10 The images show SEM images of cuprous oxide prepared in Comparative Example 5 at different magnifications. The left image is the SEM image at high magnification, and the right image is the SEM image at low magnification. Detailed Implementation
[0024] This invention provides a method for preparing submicron-sized cuprous oxide cubes, comprising the following steps: Sodium hydroxide solution was added to the copper precursor compound solution to adjust the pH of the system to ≥10. Then, morphology control agent solution and reducing agent solution were added to carry out redox reaction to obtain submicron cuprous oxide cubes. The morphology control agent is a water-soluble nonionic cellulose derivative; the reducing agent is an ascorbic acid-based reducing agent.
[0025] In this invention, the solvents for the sodium hydroxide solution, copper precursor compound solution, morphology control agent solution, and reducing agent solution are all water, specifically deionized water. This invention does not have special requirements for the preparation methods of the sodium hydroxide solution, copper precursor compound solution, morphology control agent solution, and reducing agent solution; simply dissolving the sodium hydroxide, copper precursor compound, morphology control agent, and reducing agent in water is sufficient. In specific embodiments of this invention, the preferred dissolution temperature for the sodium hydroxide is room temperature, the preferred dissolution temperature for the copper precursor compound is 0-40°C, the preferred dissolution temperature for the morphology control agent is 60°C, and the preferred dissolution temperature for the reducing agent is room temperature.
[0026] In this invention, the copper precursor compound is preferably at least one of copper nitrate and copper chloride. Specifically, the copper nitrate is copper nitrate trihydrate, and the copper chloride is copper chloride dihydrate. The concentration of the copper precursor compound solution is preferably 0.0125~0.1 mol / L, specifically 0.0125, 0.025, 0.05, or 0.1 mol / L.
[0027] In this invention, the morphology control agent is a water-soluble nonionic cellulose derivative, preferably including one or more of hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethyl methyl cellulose, and hydroxypropyl methyl cellulose; in this invention, the viscosity of the hydroxyethyl cellulose is 1000~1500 mPa·s, the viscosity of the hydroxypropyl cellulose is 1000~4000 mPa·s, the viscosity of the hydroxyethyl methyl cellulose is 12000~17000 mPa·s, and the viscosity of the hydroxypropyl methyl cellulose is 400~4000 mPa·s, preferably 4000 mPa·s; the concentration of the morphology control agent solution is preferably 0.002~0.02 g / mL, more preferably 0.0024~0.019 g / mL.
[0028] In this invention, the reducing agent is an ascorbic acid-based reducing agent, preferably one or more of ascorbic acid, ascorbate, and isofructose, wherein the ascorbate is preferably sodium ascorbate; the concentration of the reducing agent solution is 0.05~0.2 mol / L, specifically 0.05, 0.1, or 0.2 mol / L.
[0029] In this invention, the volume ratio of the morphology control agent solution, the copper precursor compound solution, and the reducing agent solution is preferably 0.5~1.5:0.5~1.5:0.5~1.5, and more specifically, it can be 1:1:1.
[0030] In this invention, the concentration of the sodium hydroxide solution is preferably 1.5~2.5 mol / L, specifically 2 mol / L. In this invention, the sodium hydroxide solution is added to the copper precursor compound solution to adjust the pH of the system to ≥10, specifically 10, 11, 12, or 13.
[0031] In this invention, the reducing agent solution is added after the morphology control agent solution has been added; the addition rate of the reducing agent solution is preferably 3~4 mL / min, and the addition method of the morphology control agent solution is preferably dropwise. In a specific embodiment of this invention, a peristaltic pump is preferably used for uniform dropwise addition.
[0032] In this invention, the temperature of the redox reaction is preferably 0~40℃, specifically 0, 10, 20 or 40℃, and the reaction time is preferably 0.5~2 h, specifically 0.5, 1, 1.5 or 2 h; the redox reaction time is counted from the time the reducing agent solution is completely added; in the redox reaction, the copper precursor compound is reduced by the reducing agent, and at the same time, under the synergistic regulation of the concentrated alkaline environment and the morphology control agent, a cubic structure is formed.
[0033] In this invention, after the redox reaction is completed, it is preferable to further centrifuge the obtained product liquid, wash and dry the obtained solid product to obtain the submicron-sized cuprous oxide cubes.
[0034] The present invention also provides submicron-sized cuprous oxide cubes prepared by the preparation method described above; in the present invention, the particle size of the submicron-sized cuprous oxide cubes is 100 nm to 1 μm.
[0035] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.
[0036] In the following examples, the viscosity of hydroxyethyl cellulose used is 1000~1500 mpa.s, the viscosity of hydroxypropyl cellulose is 1000~4000 mpa.s, the viscosity of hydroxyethyl methyl cellulose is 12000~17000 mpa.s, and the viscosity of hydroxypropyl methyl cellulose is 4000 mpa.s.
[0037] Example 1 (1) Dissolve 0.604 g of copper nitrate trihydrate in 50 mL of deionized water and stir in a water bath at 20 °C to obtain a copper nitrate solution.
[0038] (2) Dissolve 2 g of sodium hydroxide in 25 mL of deionized water, stir evenly at room temperature, and then add it to the copper nitrate solution in step (1) to adjust the pH of the precursor solution to 12.
[0039] (3) Dissolve 0.2416 g of hydroxyethyl cellulose in 50 mL of deionized water, stir evenly at 60°C, and then add it to the mixed solution in step (2) and stir evenly to obtain a mixed solution.
[0040] (4) Dissolve 0.8805 g of ascorbic acid in 50 mL of deionized water, stir evenly at room temperature, and add it to the mixture in step (3) at a rate of 4 mL / min using a peristaltic pump. React at 20°C for 1 h.
[0041] (5) After the reaction is complete, the prepared cuprous oxide solution is washed multiple times with deionized water and ethanol, and then dried in an oven at 60°C to obtain submicron cuprous oxide cubes.
[0042] The XRD pattern and SEM image of the submicron-sized cuprous oxide cubes prepared in Example 1 are shown below. Figure 1 and Figure 2 As shown, Figures 1-2 The results show that the product prepared in this embodiment is pure phase cuprous oxide with no impurity peaks; the morphology is a typical cubic structure with clear edges and smooth surface, and the size is concentrated in 100 nm~1 µm, with good dispersion.
[0043] Example 2 (1) Dissolve 1.208 g of copper nitrate trihydrate in 50 mL of deionized water and place it in a water bath at 0 °C and stir until homogeneous to obtain a copper nitrate solution.
[0044] (2) Dissolve 2 g of sodium hydroxide in 25 mL of deionized water, stir evenly at room temperature, and then add it to the copper nitrate solution in step (1) to adjust the pH of the precursor solution to 13.
[0045] (3) Dissolve 0.9664 g of hydroxypropyl cellulose in 50 mL of deionized water, stir evenly at 60 °C, and then add it to the mixed solution in step (2) and stir evenly to obtain a mixed solution.
[0046] (4) Dissolve 1.7609 g of ascorbic acid in 50 mL of deionized water, stir evenly at room temperature, and add it to the mixture in step (3) at a rate of 4 mL / min using a peristaltic pump. React at 0℃ for 2 h.
[0047] (5) After the reaction is complete, the prepared cuprous oxide solution is washed multiple times with deionized water and ethanol, and then dried in an oven at 60 °C to obtain submicron cuprous oxide cubes.
[0048] SEM image of the submicron-sized cuprous oxide cubes prepared in Example 2 is shown below. Figure 3 As shown, Figure 3 The results show that the product prepared in this example still maintains a regular cubic morphology. The difference from Example 1 is that the reaction temperature is lower (0°C). Although the low temperature slows down the reduction rate, it does not destroy the crystal growth regulation law. The morphology control agent can still effectively guide the formation of cubic structure. The size is slightly smaller than that of the product in Example 1 only because the nucleation rate is slightly higher than the growth rate. The product has good dispersibility and no obvious agglomeration.
[0049] Example 3 (1) Dissolve 0.302 g of copper nitrate trihydrate in 50 mL of deionized water and stir in a water bath at 40 °C to obtain a copper nitrate solution.
[0050] (2) Dissolve 2 g of sodium hydroxide in 25 mL of deionized water, stir evenly at room temperature, and then add it to the copper nitrate solution in step (1) to adjust the pH of the precursor solution to 10.
[0051] (3) Dissolve 0.4832 g of hydroxyethyl methylcellulose in 50 mL of deionized water, stir evenly at 60 °C, and then add it to the mixed solution in step (2) and stir evenly to obtain a mixed solution.
[0052] (4) Dissolve 0.8805 g of ascorbic acid in 50 mL of deionized water, stir evenly at room temperature, and then add it to the mixture in step (3) at a rate of 4 mL / min using a peristaltic pump. React at 40 °C for 0.5 h.
[0053] (5) After the reaction is complete, the prepared cuprous oxide solution is washed multiple times with deionized water and ethanol, and then dried in an oven at 60 °C to obtain submicron cuprous oxide cubes.
[0054] SEM image of the submicron-sized cuprous oxide cubes prepared in Example 3 is shown below. Figure 4 As shown, Figure 4The results show that the product prepared in this embodiment still has a regular cubic structure with a smooth and distortion-free surface. The difference from Example 1 is that the reaction temperature is higher (40 °C), indicating that the reduction of copper ions and the growth rate of crystal faces are accelerated by increasing the temperature. The size of this product is slightly larger than that of the product in Example 1, but the selective regulation of crystal faces by the morphology control agent is not affected, and the cubic morphology can still be stably maintained under this condition.
[0055] Example 4 (1) Dissolve 0.107 g of copper chloride dihydrate in 50 mL of deionized water and stir in a water bath at 10 °C to obtain a copper chloride solution.
[0056] (2) Dissolve 2 g of sodium hydroxide in 25 mL of deionized water, stir evenly at room temperature, and then add it to the copper nitrate solution in step (1) to adjust the pH of the precursor solution to 11.
[0057] (3) Dissolve 0.1208 g of hydroxypropyl methylcellulose in 50 mL of deionized water, stir evenly at 60 °C, and then add it to the mixed solution in step (2) and stir evenly to obtain a mixed solution.
[0058] (4) Dissolve 0.4402 g of ascorbic acid in 50 mL of deionized water, stir evenly at room temperature, and add it to the mixture in step (3) at a rate of 4 mL / min using a peristaltic pump. React at 10 °C for 1.5 h.
[0059] (5) After the reaction is complete, the prepared cuprous oxide solution is washed multiple times with deionized water and ethanol, and then dried in an oven at 60 °C to obtain submicron cuprous oxide cubes.
[0060] SEM image of the submicron-sized cuprous oxide cubes prepared in Example 4 is shown below. Figure 5 As shown, Figure 5 The results show that, in this embodiment, using copper chloride dihydrate as a copper precursor, the prepared product is still a pure-phase cubic cuprous oxide with regular morphology and good dispersibility. This proves that the method of the present invention has good compatibility with different copper precursors, and there is no need to adjust the core process parameters. The synergistic effect of the concentrated alkaline environment of the precursor solution and the morphology control agent can still stably induce the formation of cubic structure.
[0061] Comparative Example 1 This comparative example uses the same method as Example 1 to prepare submicron-sized cuprous oxide cubes, except that no morphology control agent is added. The specific steps are as follows: (1) Dissolve 0.604 g of copper nitrate trihydrate in 50 mL of deionized water and stir in a water bath at 20 °C to obtain a copper nitrate solution.
[0062] (2) Dissolve 2 g of sodium hydroxide in 25 mL of deionized water, stir evenly at room temperature, and then add it to the copper nitrate solution in step (1) to adjust the pH of the precursor solution to 10.
[0063] (3) Dissolve 0.8805 g of ascorbic acid in 50 mL of deionized water, stir evenly at room temperature, and add it to the mixture in step (2) at a rate of 4 mL / min using a peristaltic pump. React at 20°C for 1 h.
[0064] (4) After the reaction is complete, the prepared solution is washed multiple times with deionized water and ethanol, and then dried in an oven at 60 °C to obtain the sample powder.
[0065] SEM image of the cuprous oxide product prepared in Comparative Example 1 is shown below. Figure 6 As shown, through Figure 2 and Figure 6 The comparison shows that when no morphology control agent is added, the product appears as irregular polygonal particles without cubic structure characteristics. This is because the morphology control agent can selectively adsorb and inhibit the growth of cuprous oxide (111) crystal planes. Without the morphology control agent, it is impossible to achieve differentiated control of the crystal plane growth rate, and only disordered morphology particles can be generated, which cannot form a cubic structure.
[0066] Comparative Example 2 This comparative example uses the same method as Example 1 to prepare submicron-sized cuprous oxide cubes, except that sodium hydroxide is not added (the precursor solution is acidic). The specific steps are as follows: (1) Dissolve 0.604 g of copper nitrate trihydrate in 50 mL of deionized water (the pH of the solution is 4), and stir evenly in a water bath at 20 °C to obtain a copper nitrate solution.
[0067] (2) Dissolve 0.2416 g of hydroxyethyl cellulose in 50 mL of deionized water, stir evenly at 60 °C, and then add it to the mixed solution in step (1) and stir evenly to obtain a mixed solution.
[0068] (3) Dissolve 0.8805 g of ascorbic acid in 50 mL of deionized water, stir evenly at room temperature, and add it to the mixture in step (2) at a rate of 4 mL / min using a peristaltic pump. React at 20°C for 1 h.
[0069] (4) After the reaction is complete, the prepared solution is washed multiple times with deionized water and ethanol, and then dried in an oven at 60 °C to obtain the sample powder.
[0070] SEM image of the cuprous oxide product prepared in Comparative Example 2 is shown below. Figure 7 As shown, through Figure 2 and Figure 7The comparison shows that when the precursor solution is acidic, the product is a mixture of amorphous and irregular particles without a crystalline structure. This proves that a concentrated alkaline environment is key to the formation of the cuprous oxide crystalline phase: under acidic conditions, stable copper-based complexes cannot be formed, which neither inhibits the formation of impurity phases nor creates conditions for the selective adsorption of morphology control agents, thus preventing the formation of the target crystalline phase.
[0071] Comparative Example 3 This comparative example uses the same method as Example 1 to prepare submicron-sized cuprous oxide cubes, except that the pH of the precursor solution is adjusted to 9. The specific steps are as follows: (1) Dissolve 0.604 g of copper nitrate trihydrate in 50 mL of deionized water and stir in a water bath at 20 °C to obtain a copper nitrate solution.
[0072] (2) Dissolve 2 g of sodium hydroxide in 25 mL of deionized water, stir evenly at room temperature, and then add it to the copper nitrate solution in step (1) to adjust the pH of the precursor solution to 9.
[0073] (3) Dissolve 0.2416 g of hydroxyethyl cellulose in 50 mL of deionized water, stir evenly at 60 °C, and then add it to the mixed solution in step (2) and stir evenly to obtain a mixed solution.
[0074] (4) Dissolve 0.8805 g of ascorbic acid in 50 mL of deionized water, stir evenly at room temperature, and add it to the mixture in step (3) at a rate of 4 mL / min using a peristaltic pump. React at 20°C for 1 h.
[0075] (5) After the reaction is complete, the prepared solution is washed multiple times with deionized water and ethanol, and then dried in an oven at 60 °C to obtain the sample powder.
[0076] SEM image of the cuprous oxide product prepared in Comparative Example 3 is shown below. Figure 8 As shown, through Figure 2 and Figure 8 The comparison shows that when the precursor solution is weakly alkaline, the product is an irregular particle with no regular cubic morphology. This spectrum indicates that even in an alkaline environment, if the pH does not reach the concentrated alkaline range (≥10), the requirements for the formation of a cubic structure cannot be met. Under weakly alkaline conditions, the stability of the complex formed by copper ions is insufficient, the selective adsorption of the morphology control agent on the crystal face is weakened, and the difference in growth rate between the (100) and (111) crystal faces cannot be effectively amplified. At the same time, it is difficult to completely suppress the oxidation of cuprous oxide, and ultimately a pure phase and regular cubic structure cannot be formed.
[0077] Comparative Example 4 This comparative example uses the same method as Example 1 to prepare submicron-sized cuprous oxide cubes, except that the morphology control agent is replaced with sodium carboxymethyl cellulose. The specific steps are as follows: (1) Dissolve 0.8805 g of copper nitrate trihydrate in 50 mL of deionized water and stir in a water bath at 20 °C to obtain a copper nitrate solution.
[0078] (2) Dissolve 2 g of sodium hydroxide in 25 mL of deionized water, stir evenly at room temperature, and then add it to the copper nitrate solution in step (1) to adjust the pH of the precursor solution to 12.
[0079] (3) Dissolve 0.2416 g of sodium carboxymethyl cellulose in 50 mL of deionized water, stir evenly at 60 °C, and then add it to the mixed solution in step (2) and stir evenly to obtain a mixed solution.
[0080] (4) Dissolve 0.8805 g of ascorbic acid in 50 mL of deionized water, stir evenly at room temperature, and add it to the mixture in step (3) at a rate of 4 mL / min using a peristaltic pump. React at 20°C for 1 h.
[0081] (5) After the reaction is complete, the prepared solution is washed multiple times with deionized water and ethanol, and then dried in an oven at 60 °C to obtain the sample powder.
[0082] SEM image of the cuprous oxide product prepared in Comparative Example 4 is shown below. Figure 9 As shown, through Figure 2 and Figure 9 The comparison shows that when the morphology control agent is replaced with sodium carboxymethyl cellulose (an anionic cellulose derivative), the product exhibits irregular aggregates and an irregular cubic morphology. This is because sodium carboxymethyl cellulose contains anionic carboxyl groups (-COO). - Excessive electrostatic adsorption between the (100) and (111) crystal planes can lead to the formation of a dense coating layer that excessively hinders crystal plane growth and easily induces local agglomeration. This makes it impossible to precisely control the difference in growth rates between the (100) and (111) crystal planes, thus failing to form a pure-phase cubic structure. This result contrasts sharply with the water-soluble nonionic cellulose derivatives used in this invention: the morphology control agent of this invention only forms moderately strong hydrogen bonds with the (111) crystal plane through hydroxyl groups. This can moderately inhibit the growth of the (111) crystal plane and amplify the difference in crystal plane growth rates without excessive coating or inducing oxidation. Ultimately, it can stably obtain pure-phase cubic cuprous oxide with uniform size of 100 nm to 1 µm, fully verifying the significant advantages of the water-soluble nonionic cellulose derivatives selected in this invention in crystal plane regulation and product purity control.
[0083] Comparative Example 5 This comparative example uses the same method as Example 1 to prepare submicron-sized cuprous oxide cubes, except that the morphology control agent is replaced with ethyl cellulose. The specific steps are as follows: (1) Dissolve 0.604 g of copper nitrate trihydrate in 50 mL of deionized water and stir in a water bath at 20°C to obtain a copper nitrate solution.
[0084] (2) Dissolve 2 g of sodium hydroxide in 25 mL of deionized water, stir evenly at room temperature, and then add it to the copper nitrate solution in step (1) to adjust the pH of the precursor solution to 12.
[0085] (3) Dissolve 0.2416 g of ethyl cellulose in 50 mL of ethanol, stir evenly at 80°C, and then add it to the mixed solution in step (2) and stir evenly to obtain a mixed solution.
[0086] (4) Dissolve 0.8805 g of ascorbic acid in 50 mL of deionized water, stir evenly at room temperature, and add it to the mixture in step (3) at a rate of 4 mL / min using a peristaltic pump. React at 20°C for 1 h.
[0087] (5) After the reaction is complete, the prepared solution is washed multiple times with deionized water and ethanol, and then dried in an oven at 60 °C to obtain the sample powder.
[0088] SEM image of the cuprous oxide product prepared in Comparative Example 5 is shown below. Figure 10 As shown, through Figure 2 and Figure 10 The comparison shows that when the morphology control agent is replaced with ethyl cellulose, the product is an irregularly shaped aggregate of particles without cubic structure and with a disordered size distribution. This is because ethyl cellulose is insoluble in water and must be dissolved in ethanol before being added to the reaction system. It is prone to agglomeration and uneven dispersion in aqueous solution and cannot be uniformly adsorbed on the crystal face to achieve directional control. During the reaction, the copper compound directly contacts sodium hydroxide and ascorbic acid, and cannot amplify the difference in growth rate between the (100) and (111) crystal faces through the selective adsorption of the morphology control agent. In the end, only non-cubic particles and aggregates can be obtained. This result contrasts sharply with the water-soluble nonionic cellulose derivatives used in this invention: the morphology control agent of this invention is completely soluble in the aqueous phase and can be uniformly dispersed in the reaction system. It forms moderately strong hydrogen bonds with the (111) crystal facets through abundant -OH groups, precisely controlling the difference in crystal facet growth rates. At the same time, it utilizes steric hindrance to avoid aggregation, and finally, it can stably obtain pure-phase cubic cuprous oxide with uniform size of 100 nm to 1 µm. This fully verifies the core advantages of water-soluble nonionic cellulose derivatives in crystal facet control, product morphology and purity control.
[0089] Examples 1-4 reveal the effects of temperature and precursor type on product size, demonstrating that cubic structures can still be stably formed within the range of 0-40℃ under different precursor conditions, exhibiting excellent process controllability and compatibility. A comparison of Examples 1-5 with Example 1 clarifies that a water-soluble nonionic cellulose derivative morphology control agent and a concentrated alkaline environment with pH ≥ 10 are the two essential conditions for cubic structure formation. The lack of a morphology control agent, the use of excessively adsorbed sodium carboxymethyl cellulose, or water-insoluble ethyl cellulose all prevent the differential control of crystal face growth rates. Furthermore, in a weakly alkaline environment (pH=9), the stability of the complex and the requirements for crystal face control cannot be met, thus preventing the preparation of the target product.
[0090] The results of the above examples and comparative examples show that the synergistic mechanism of the concentrated alkaline environment regulating the thermodynamics of the crystal phase and the water-soluble nonionic cellulose derivative morphology control agent regulating the crystal face growth kinetics provides a reference for the effectiveness and parameter optimization direction of the liquid-phase chemical reduction method for preparing submicron cubic cuprous oxide.
[0091] In summary, this invention achieves a mild and low-cost preparation of submicron-sized cuprous oxide cubes by synergistically controlling the morphology control agent, reaction pH, reduction type, and reaction conditions. Furthermore, the preparation method is environmentally friendly and simple to operate, possessing significant academic value and industrial application potential. Simultaneously, the submicron-sized cuprous oxide cubes prepared by this invention exhibit uniform morphology, a size distribution of 100 nm to 1 µm, and high purity, demonstrating broad application prospects.
[0092] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for preparing submicron-sized cuprous oxide cubes, characterized in that, Includes the following steps: Sodium hydroxide solution was added to the copper precursor compound solution to adjust the pH of the system to ≥10. Then, morphology control agent solution and reducing agent solution were added to carry out redox reaction to obtain submicron cuprous oxide cubes. The morphology control agent is a water-soluble nonionic cellulose derivative; the reducing agent is an ascorbic acid-based reducing agent.
2. The preparation method according to claim 1, characterized in that, The water-soluble nonionic cellulose derivative includes one or more of hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethyl methyl cellulose, and hydroxypropyl methyl cellulose; the viscosity of the hydroxyethyl cellulose is 1000~1500 mPa·s, the viscosity of the hydroxypropyl cellulose is 1000~4000 mPa·s, the viscosity of the hydroxyethyl methyl cellulose is 12000~17000 mPa·s, and the viscosity of the hydroxypropyl methyl cellulose is 400~4000 mPa·s. The ascorbic acid reducing agents include one or more of ascorbic acid, ascorbate, and isoflavone.
3. The preparation method according to claim 1, characterized in that, The copper precursor compound is at least one of copper nitrate and copper chloride.
4. The preparation method according to claim 1, characterized in that, The concentration of the copper precursor compound solution is 0.0125~0.1 mol / L; the concentration of the morphology control agent solution is 0.002~0.02 g / mL; the concentration of the reducing agent solution is 0.05~0.2 mol / L; and the volume ratio of the morphology control agent solution, the copper precursor compound solution, and the reducing agent solution is 0.5~1.5:0.5~1.5:0.5~1.
5.
5. The preparation method according to claim 1, characterized in that, The concentration of the sodium hydroxide solution is 1.5~2.5 mol / L.
6. The preparation method according to claim 1, characterized in that, The reducing agent solution is added after the morphology control agent solution has been added; the addition rate of the reducing agent solution is 3~4 mL / min.
7. The preparation method according to claim 1, characterized in that, The redox reaction is carried out at a temperature of 0~40℃ for a time of 0.5~2 h.
8. The preparation method according to claim 1, characterized in that, After the redox reaction is completed, the product liquid is centrifuged, the solid product is washed and dried to obtain the submicron-sized cuprous oxide cubes.
9. Submicron-sized cuprous oxide cubes prepared by the preparation method according to any one of claims 1 to 8.