Preparation process of high-purity nano nickel oxide
High-purity nickel oxide was prepared by combining oleamine as a soft template and a composite dispersant as a microwave-assisted process, which solved the problem that traditional methods were difficult to control the particle size and purity of nano nickel oxide, and achieved the industrial application of nano nickel oxide with high specific surface area.
Patent Information
- Application Number
- CN202510572478.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-06
- Publication Date
- 2025-08-08
AI Technical Summary
The prior art is difficult to prepare high-purity nano nickel oxide with small average grain size and large specific surface area, which is difficult to meet the needs of the new energy field.
Using oleamine as a soft template, combined with composite dispersant and microwave-assisted process, the precursor mixture is prepared by adding composite dispersant and reacting with microwave-assisted treatment, and then centrifugation, washing, drying and calcination is performed to obtain high-purity nickel oxide.
Nano nickel oxide with smaller average grain size, larger specific surface area and higher purity is prepared, which is suitable for industrial applications in the new energy field.
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of nano nickel oxide preparation, in particular to a preparation process of high-purity nano nickel oxide. Background Art
[0002] Nano-nickel oxide (NiO) is a transition metal oxide with unique physical and chemical properties, including high specific surface area, excellent electrochemical activity, catalytic performance and light absorption capacity. It has attracted much attention in the fields of photocatalysis and electrochemical energy storage.
[0003] Traditional preparation methods for nano-nickel oxide include chemical precipitation, hydrothermal and sol-gel methods. The chemical precipitation method involves the reaction of nickel salts (such as nickel nitrate and nickel chloride) with alkaline precipitants (such as NaOH and NH3·H2O) to form a precursor, which is then calcined to obtain nano-nickel oxide. The process is relatively simple, but the particle size distribution of the product is relatively wide. In the hydrothermal method, nickel salts and reaction media (such as water and ethanol) are reacted in a closed reactor under high temperature and high pressure to generate nanoparticles. This method can control the morphology (such as nanosheets and nanospheres), but the cost is relatively high. The sol-gel method utilizes nickel salt precursors (such as nickel acetylacetonate) to hydrolyze and condense to form a sol, which is then dried and calcined to obtain nano-nickel oxide. Although this method has a complicated process, the product has high purity.
[0004] With the development of the new energy field, it has been discovered that nano-nickel oxide with a high specific surface area can be used for the negative electrode of lithium batteries to improve the cycle stability of lithium batteries. However, the traditional sol-gel method has difficulty in controlling the directional growth of nano-nickel oxide, and it is difficult to obtain high-purity nano-nickel oxide products with a small average grain size and a large specific surface area. Summary of the Invention
[0005] The purpose of the present invention is to provide a preparation process for high-purity nano-nickel oxide, which uses oleylamine as a soft template, adds a composite dispersant and combines with a microwave-assisted process to prepare a high-purity nano-nickel oxide product with a small average grain size and a large specific surface area.
[0006] The purpose of the present invention can be achieved through the following technical solutions:
[0007] A preparation process of high-purity nano nickel oxide comprises the following steps:
[0008] Step 1: Add nickel acetylacetonate and the mixed solution into a reactor, stir at a speed of 200-500 r / min for 5-10 minutes, then add a composite dispersant and oleylamine as a soft template into the reactor, continue stirring at 60-65°C for 10-15 minutes, adjust the pH value to 8-9 with ammonia water, and then stir the reaction at 180-190°C for 10-14 hours under microwave assistance to obtain a precursor mixture.
[0009] Furthermore, the usage ratio of nickel acetylacetonate, mixed solution, composite dispersant and oleylamine is 1-1.1 g: 35-40 mL: 0.02-0.03: 7-10 mL.
[0010] Furthermore, the mixed solution is prepared by mixing toluene and anhydrous ethanol in a volume ratio of 2:1-2.
[0011] Furthermore, the microwave-assisted power density was 0.6-0.8 W / mL.
[0012] Step 2: Centrifuge the precursor mixture at 8000r / min, collect the precipitate, wash the precipitate with acetone and anhydrous ethanol 2-3 times respectively, vacuum dry it at 60-80℃ to constant weight, transfer it to a muffle furnace, calcine it at 650-750℃ for 3-5h, grind it to obtain high-purity nano nickel oxide.
[0013] Furthermore, the composite dispersant is prepared by the following steps:
[0014] Step 1: Add allyl alcohol polyoxyethylene ether, allyltrimethylsilane, anhydrous methanol and deionized water into a reactor and stir and mix, heat to 50-55° C., add ammonium persulfate as an initiator into the reactor, stir at 200-500 r / min for 3-5 minutes, then add dodecanethiol as a chain transfer agent and continue stirring for 3-5 minutes, then add acrylic acid into the reactor at 70-75° C., stir and react for 2-3 hours, cool naturally to room temperature, adjust the pH value of the reaction system to 7-8 with sodium hydroxide solution, dialyze for 24 hours using a dialysis bag with a molecular weight cutoff of 2000 Da, and freeze-dry the dialyzed product to obtain a copolymer powder.
[0015] Furthermore, the mass ratio of allyl alcohol polyoxyethylene ether, allyltrimethylsilane, anhydrous methanol, deionized water, initiator, chain transfer agent and acrylic acid is 10-12:1.2-1.5:10-12:8-10:2-3:0.15-0.2:0.05-0.08.
[0016] Step 2: Evenly mix the copolymer powder and lactic acid in a mass ratio of 5:1-2 to obtain a composite dispersant.
[0017] Beneficial effects of the present invention:
[0018] The present invention improves the process, uses oleylamine as a soft template, adds a composite dispersant and combines with a microwave-assisted process to prepare nano nickel oxide with higher purity, larger specific surface area and larger pore volume, and its average grain size is smaller, which is conducive to the industrial application of porous nickel oxide with high specific surface area in the field of new energy.
[0019] The present invention uses oleylamine as a template agent. The amino group has a reducing effect on nickel acetylacetonate, and oleylamine can guide Ni 2+ Directed deposition facilitates the synthesis of porous nickel oxide. The composite dispersant, comprising copolymer powder and lactic acid, acts as a high-molecular-weight substance, providing steric hindrance and reducing sol particle aggregation. Lactic acid limits sol particle growth, preventing rapid growth that can lead to impurity entrapment and a decrease in average particle size. Microwave-assisted reaction improves reaction uniformity and helps reduce the average grain size of the nickel oxide product. DETAILED DESCRIPTION
[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0021] Example 1: A process for preparing high-purity nano-nickel oxide, comprising the following steps:
[0022] S1: 10 kg of allyl alcohol polyoxyethylene ether, 1.2 kg of allyltrimethylsilane, 10 kg of anhydrous methanol and 8 kg of deionized water were added to a reactor and stirred and mixed. The temperature was raised to 50°C, 0.15 kg of ammonium persulfate as an initiator was added to the reactor, and the mixture was stirred at 200 r / min for 3 minutes. Then, 0.05 kg of dodecanethiol as a chain transfer agent was added and the stirring was continued for 3 minutes. Then, 2 kg of acrylic acid was added to the reactor at 70°C, the mixture was stirred for 2 hours, and the mixture was naturally cooled to room temperature. The pH value of the reaction system was adjusted to 7 with sodium hydroxide solution, and the mixture was dialyzed for 24 hours using a dialysis bag with a molecular weight cutoff of 2000 Da. The dialyzed product was freeze-dried to obtain a copolymer powder. The copolymer powder and lactic acid were evenly mixed in a mass ratio of 5:1-2 to obtain a composite dispersant.
[0023] S2: Toluene and anhydrous ethanol were mixed in a volume ratio of 2:1 to obtain a mixed solution; 1 kg of nickel acetylacetonate and 35 L of the mixed solution were added to the reactor and stirred at a speed of 200 r / min for 5 minutes. Then, 0.02 kg of a composite dispersant and 7 L of oleylamine as a soft template were added to the reactor. The mixture was stirred at 60 ° C for 10 minutes, and the pH value was adjusted to 8 with ammonia water. Then, the reaction was stirred for 10 hours at a temperature of 180 ° C with the assistance of microwave with a power density of 0.6 W / mL to obtain a precursor mixture.
[0024] S3: The precursor mixture was centrifuged at 8000 r / min, and the precipitate was collected. The precipitate was washed twice with acetone and anhydrous ethanol respectively, dried under vacuum at 60°C to constant weight, transferred to a muffle furnace, calcined at 650°C for 3h, and ground to obtain high-purity nano-nickel oxide.
[0025] Example 2: A process for preparing high-purity nano-nickel oxide, comprising the following steps:
[0026] S1: 12 kg of allyl alcohol polyoxyethylene ether, 1.5 kg of allyltrimethylsilane, 12 kg of anhydrous methanol and 10 kg of deionized water were added to a reactor and stirred and mixed. The temperature was raised to 55°C, 0.2 kg of ammonium persulfate as an initiator was added to the reactor, and the mixture was stirred at 500 r / min for 5 minutes. Then, 0.08 kg of dodecanethiol as a chain transfer agent was added and the stirring was continued for 5 minutes. Then, 3 kg of acrylic acid was added to the reactor at 75°C, the mixture was stirred for 3 hours, and the mixture was naturally cooled to room temperature. The pH value of the reaction system was adjusted to 8 with sodium hydroxide solution, and the mixture was dialyzed for 24 hours using a dialysis bag with a molecular weight cutoff of 2000 Da. The dialyzed product was freeze-dried to obtain a copolymer powder. The copolymer powder and lactic acid were evenly mixed in a mass ratio of 5:1-2 to obtain a composite dispersant.
[0027] S2: Toluene and anhydrous ethanol were mixed in a volume ratio of 1:1 to obtain a mixed solution; 1.1 kg of nickel acetylacetonate and 40 L of the mixed solution were added to the reactor and stirred at a speed of 500 r / min for 10 min. Then, 0.03 kg of a composite dispersant and 10 L of oleylamine as a soft template were added to the reactor. Stirring was continued at 65 ° C for 15 min. The pH value was adjusted to 9 with ammonia water. Then, the reaction was stirred for 14 h at a temperature of 190 ° C with the assistance of microwave with a power density of 0.8 W / mL to obtain a precursor mixture.
[0028] S3: The precursor mixture was centrifuged at 8000 r / min, and the precipitate was collected. The precipitate was washed three times with acetone and anhydrous ethanol respectively, dried under vacuum at 80°C to constant weight, transferred to a muffle furnace, calcined at 750°C for 5h, and ground to obtain high-purity nano-nickel oxide.
[0029] Example 3: A process for preparing high-purity nano-nickel oxide, comprising the following steps:
[0030] S1: 11 kg of allyl alcohol polyoxyethylene ether, 1.35 kg of allyltrimethylsilane, 11 kg of anhydrous methanol and 9 kg of deionized water were added to a reactor and stirred and mixed. The temperature was raised to 52.5°C, 0.175 kg of ammonium persulfate as an initiator was added to the reactor, and the mixture was stirred at 350 r / min for 4 min. Then, 0.065 kg of dodecanethiol as a chain transfer agent was added and the stirring was continued for 4 min. Then, 2.5 kg of acrylic acid was added to the reactor at 72.5°C, the mixture was stirred for 2.5 h, and the mixture was naturally cooled to room temperature. The pH value of the reaction system was adjusted to 7.5 with sodium hydroxide solution, and the mixture was dialyzed for 24 h using a dialysis bag with a molecular weight cutoff of 2000 Da. The dialyzed product was freeze-dried to obtain a copolymer powder. The copolymer powder and lactic acid were evenly mixed in a mass ratio of 5:1-2 to obtain a composite dispersant.
[0031] S2: Toluene and anhydrous ethanol were mixed in a volume ratio of 2:1.5 to obtain a mixed solution; 1.05 kg of nickel acetylacetonate and 37.5 L of the mixed solution were added to the reactor and stirred at a speed of 350 r / min for 7.5 min. Then, 0.025 kg of a composite dispersant and 8.5 L of oleylamine as a soft template were added to the reactor. The mixture was stirred at 62.5 ° C for 12.5 min, and the pH value was adjusted to 8.5 with ammonia water. Then, the reaction was stirred for 12 h at a temperature of 185 ° C with the assistance of microwave with a power density of 0.7 W / mL to obtain a precursor mixture.
[0032] S3: The precursor mixture was centrifuged at 8000 r / min, and the precipitate was collected. The precipitate was washed 2.5 times with acetone and anhydrous ethanol respectively, and vacuum dried at 70°C to constant weight. The precipitate was transferred to a muffle furnace, calcined at 700°C for 4 hours, and ground to obtain high-purity nano-nickel oxide.
[0033] Comparative Example 1: Based on Example 3, no composite dispersant was added in step S2, and the copolymer powder of the same mass as in step S1 was directly used as the dispersant. The other steps remained unchanged to prepare nano nickel oxide.
[0034] Comparative Example 2: Based on Example 3, a composite dispersant was added in step S2, and the same mass of lactic acid was directly used as the dispersant. The other steps remained unchanged to prepare nano nickel oxide.
[0035] Comparative Example 3: Based on Example 3, step S2 is not subjected to microwave-assisted treatment, and the remaining steps remain unchanged to prepare nano-nickel oxide.
[0036] Performance tests were conducted on Examples 1 to 3 and Comparative Examples 1 to 3. The results of the average grain size, specific surface area (nitrogen adsorption method), pore volume, and purity of each nano-nickel oxide are shown in Table 1:
[0037] Table 1
[0038] project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Average grain size (nm) 12 16 15 25 31 22 <![CDATA[Specific surface area (m 2 / g)]]> 135 117 123 85 74 102 Pore volume (mL / g) 0.30 0.24 0.26 0.15 0.12 0.18 purity(%) 99.6 99.7 99.6 98.5 97.8 99.0
[0039] It can be seen from Table 1 that the nano nickel oxide prepared in Examples 1 to 3 has higher purity, larger specific surface area and larger pore volume, and its average grain size is smaller.
[0040] The increased average grain size in Comparative Example 1 is likely due to the lack of lactic acid's restrictive effect on sol particle growth. Rapid grain growth can also lead to impurity entrapment, resulting in reduced purity. The sole use of lactic acid in Comparative Example 2, lacking the steric hindrance provided by the ternary polymer, can lead to severe agglomeration of sol particles, affecting properties such as the average grain size of the product. Furthermore, excessive lactic acid levels can result in residues, affecting the purity of the nano-nickel oxide product. Comparative Example 3 demonstrates that microwave-assisted reaction can improve reaction uniformity and reduce the average grain size of the nickel oxide product.
[0041] It should be noted that, in this document, terms such as "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements that are inherent to such process, method, article or apparatus.
[0042] While the embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various changes, modifications, substitutions, and alterations can be made to the embodiments without departing from the principles and spirit of the invention.
Claims
1. A process for preparing high-purity nano nickel oxide, characterized in that: The steps include: Step 1: Add nickel acetylacetonate and the mixed solution into a reactor, stir at 200-500 r / min for 5-10 minutes, then add the composite dispersant and oleylamine, continue stirring at 60-65°C for 10-15 minutes, adjust the pH value to 8-9 with ammonia water, and stir the reaction at 180-190°C for 10-14 hours under microwave assistance to obtain a precursor mixture; Step 2: Centrifuge the precursor mixture at 8000r / min, collect the precipitate, wash the precipitate with acetone and anhydrous ethanol 2-3 times respectively, vacuum dry it at 60-80℃ to constant weight, transfer it to a muffle furnace, calcine it at 650-750℃ for 3-5h, grind it to obtain high-purity nano nickel oxide.
2. The process for preparing high-purity nano nickel oxide according to claim 1, wherein: The usage ratio of the nickel acetylacetonate, the mixed solution, the composite dispersant and oleylamine is 1-1.1 g: 35-40 mL: 0.02-0.03: 7-10 mL.
3. The process for preparing high-purity nano nickel oxide according to claim 1, wherein: The mixed solution is prepared by mixing toluene and anhydrous ethanol in a volume ratio of 2:1-2.
4. The process for preparing high-purity nano nickel oxide according to claim 1, wherein: The microwave-assisted power density is 0.6-0.8 W / mL.
5. The process for preparing high-purity nano nickel oxide according to claim 1, wherein: The composite dispersant is obtained by mixing copolymer powder and lactic acid in a mass ratio of 5:1-2.
6. The process for preparing high-purity nano nickel oxide according to claim 5, wherein: The copolymer powder is prepared by the following steps: Allyl alcohol polyoxyethylene ether, allyl trimethylsilane, anhydrous methanol and deionized water are added to a reactor and stirred and mixed. The temperature is raised to 50-55° C., ammonium persulfate is added to the reactor, and stirring is carried out at 200-500 r / min for 3-5 minutes. Dodecanethiol is then added and stirring is continued for 3-5 minutes. Then, acrylic acid is added to the reactor at 70-75° C., and the mixture is stirred for reaction for 2-3 hours. The mixture is naturally cooled to room temperature, and the pH value of the reaction system is adjusted to 7-8 with sodium hydroxide solution. The mixture is dialyzed for 24 hours using a dialysis bag with a molecular weight cutoff of 2000 Da. The dialyzed product is freeze-dried to obtain a copolymer powder.
7. The process for preparing high-purity nano nickel oxide according to claim 6, wherein: The mass ratio of the allyl alcohol polyoxyethylene ether, allyl trimethylsilane, anhydrous methanol, deionized water, initiator, chain transfer agent and acrylic acid is 10-12: 1.2-1.5：10-12：8-10：2-3：0.15-0.2：0.05-0.08。