Rod-like nickel oxide material and method for producing the same

Abstract

The application provides a rod-shaped nickel oxide material and a preparation method thereof. The preparation method comprises the following steps: S1, mixing raw materials including a nickel salt solution and an alkali solution to obtain a first mixture; S2, mixing raw materials including the first mixture and a surfactant to obtain a second mixture; S3, sequentially performing third mixing and aging reaction on raw materials including the second mixture and an oxalate solution to obtain a third mixture; and S4, sequentially performing suction filtration, washing, drying and calcination on the third mixture to obtain the rod-shaped nickel oxide material; wherein the pH value of the first mixture is 7.0-9.0; and the calcination temperature is 580-700 DEG C. The rod-shaped nickel oxide material prepared by the above method is mainly rod-shaped and has uniform particles, so that the specific surface energy and surface activity of the rod-shaped nickel oxide material are enhanced, and the application thereof is widened.

Description

Technical Field

[0001] This invention relates to the field of nickel oxide material preparation technology, and more specifically, to a rod-shaped nickel oxide material and its preparation method. Background Technology

[0002] The performance of ultrafine powders primarily depends on their morphological characteristics, with particle size and shape being fundamental features that determine the overall and surface properties of the powder. Nickel compound powders exhibit diverse crystal forms and morphological characteristics, resulting in varying physicochemical properties under different conditions. Therefore, nickel compound powders hold broad application prospects in battery electrodes, catalysts, semiconductors, and magnetic materials. Furthermore, their morphological properties can significantly enhance the performance of subsequent battery electrodes, catalysts, and other materials, further expanding the applications of nickel-containing materials.

[0003] Chinese patent application CN110211813B discloses a rod-shaped nickel hydroxide electrode material, its preparation method, and a supercapacitor made from it. This patent focuses on nickel hydroxide, which has a high theoretical specific capacitance, using nickel nitrate as the nickel source, ammonia as a precipitant and complexing agent, distilled water as the solvent, and sodium chloride as a morphology modifier. Simultaneously, it utilizes the salt effect to prepare a nickel oxide electrode material with a rod-shaped structure. However, this invention requires a constant-temperature oil bath to evaporate the solvent in the system to a viscous state during preparation, and necessitates repeated washing of the viscous product in centrifuge tubes. The preparation process is cumbersome and complex, consuming a large amount of energy for evaporation, resulting in high energy consumption.

[0004] Chinese patent application CN107240507B discloses a nanoporous nickel / nickel oxide supercapacitor electrode material and its preparation method. The method involves first preparing Ni-Ti-Zr-Al precursor amorphous alloy strips under controlled process conditions using a vacuum spinning machine; secondly, preparing nanoporous nickel through dealloying; and finally, preparing rod-shaped nickel oxide through oxidation soaking-heat treatment. However, the preparation process is complex and requires a certain level of vacuum.

[0005] Therefore, there is an urgent need to develop a simple preparation method for rod-shaped fine nickel oxide powder materials with simple preparation process and conditions. Summary of the Invention

[0006] The main objective of this invention is to provide a rod-shaped nickel oxide material and its preparation method, so as to solve the problems of complex preparation process and reaction conditions and uneven rod-shaped nickel oxide particles in the prior art.

[0007] To achieve the above objectives, according to one aspect of the present invention, a method for preparing rod-shaped nickel oxide material is provided, the method comprising: step S1, first mixing raw materials including a nickel salt solution and an alkaline solution to obtain a first mixture; step S2, second mixing raw materials including the first mixture and a surfactant raw material to obtain a second mixture; step S3, sequentially subjecting raw materials including the second mixture and an oxalate solution to a third mixing and aging reaction to obtain a third mixture; and step S4, sequentially filtering, washing, drying, and calcining the third mixture to obtain rod-shaped nickel oxide material; wherein the pH value of the first mixture is 7.0 to 9.0; and the calcination temperature is 580 to 700°C.

[0008] Furthermore, in step S1 above, the first mixing is carried out by first stirring under ultrasonic conditions, wherein the temperature of the first stirring is 60-90℃ and the speed of the first stirring is 100-500 r / min.

[0009] Further, in step S1 above, the molar concentration of the nickel salt solution is 0.02 to 0.1 mol / L, based on the nickel ions in the nickel salt solution; the nickel salt solution is selected from any one or more of nickel sulfate solution, nickel chloride solution, and nickel nitrate solution; and / or, the alkaline solution is selected from any one or more of sodium hydroxide solution, potassium hydroxide solution, and ammonia water.

[0010] Further, in step S2 above, the mass ratio of the surfactant to the first mixture is 0.2 to 5:1000; and / or, the surfactant is a sulfonic acid surfactant and / or a sulfate ester surfactant.

[0011] Furthermore, in step S3 above, a third mixing is carried out by a second stirring, the second stirring speed is 100-300 r / min, and the second stirring time is 15-120 min.

[0012] Further, in step S3 above, the molar concentration of the oxalate solution is 0.05–0.6 mol / L, based on the oxalate ions in the oxalate solution; the oxalate solution is selected from any one or more of sodium oxalate solution, potassium oxalate solution, and ammonium oxalate solution; and / or, based on the oxalate ions in the oxalate solution and the nickel ions in the nickel salt solution, the molar ratio of the oxalate solution to the nickel salt solution is 0.5–2:1.

[0013] Furthermore, in step S3 above, the aging reaction temperature is 60–85°C, and the aging reaction time is 150–200 min.

[0014] Furthermore, in step S4 above, the filtered mixture is washed sequentially with water and ethanol.

[0015] Furthermore, in step S4 above, the drying temperature is 75–120°C, the drying time is 180–360 min; and / or, the calcination time is 100–250 min.

[0016] According to another aspect of the present invention, a rod-shaped nickel oxide material is provided, which is prepared by the above-described preparation method, wherein the D50 particle size of the rod-shaped nickel oxide material is ≤15μm.

[0017] By applying the technical solution of this invention, the rod-shaped nickel oxide material prepared by the preparation method of this application has a rod-shaped morphology and uniform particle size, thereby enhancing the specific surface energy and surface activity of the rod-shaped nickel oxide material and thus broadening its applications. Specifically, by adding an alkaline solution in step S1, the pH value of the first mixture can be controlled to maintain it within the above-mentioned range to form a slightly alkaline environment. During the growth process, the alkaline environment causes the crystals to preferentially grow along a specific direction, thereby forming a rod-shaped structure. At the same time, the adsorption and desorption process of hydroxide ions on the crystal surface affects the surface energy of each crystal facet. Crystal faces with lower surface energy grow at a slower rate, while crystal faces with higher surface energy grow at a faster rate, which is beneficial for better control of the morphology of the nickel oxide material to be rod-shaped and for making the particle size and distribution more uniform. In step S2, the addition of a surfactant can adsorb onto the surface of the subsequently generated nickel oxalate precipitate particles to form a protective film, increasing the electrostatic repulsion between particles, thereby improving the dispersion effect and helping the subsequent nickel oxide to form a rod-shaped structure. In step S3, the oxalate ions in the oxalate solution react with the nickel ions in the nickel salt solution in the second mixture to form a precipitation reaction, forming nickel oxalate precipitate. Excess liquid in the third mixture is removed by filtration, and impurities on the surface of the nickel oxalate precipitate are removed by washing. Finally, the dried nickel oxalate is calcined to decompose it into nickel oxide. Controlling the calcination temperature within the aforementioned range improves the crystallinity and morphology of the nickel oxide material, promotes the stabilization of the rod-shaped structure, and thus yields pure rod-shaped nickel oxide material. Furthermore, the preparation process of this application is simple, with simple preparation conditions and easy operation, and no harmful gases are generated during the preparation process, thereby reducing the need for tail gas treatment. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0019] Figure 1 SEM images of the rod-shaped nickel oxide material in Embodiment 1 of this application are shown;

[0020] Figure 2 SEM images of the rod-shaped nickel oxide material in Comparative Example 1 of this application are shown. Detailed Implementation

[0021] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0022] As analyzed in the background section of this application, the existing technology has the problems of complex preparation process and reaction conditions for rod-shaped nickel oxide and uneven rod-shaped nickel oxide particles. In order to solve the above problems, this application provides a rod-shaped nickel oxide material and its preparation method.

[0023] In a typical embodiment of this application, a method for preparing rod-shaped nickel oxide material is provided. The method includes: step S1, mixing raw materials including a nickel salt solution and an alkaline solution to obtain a first mixture; step S2, mixing the first mixture and a surfactant raw material to obtain a second mixture; step S3, sequentially mixing and aging the raw materials including the second mixture and an oxalate solution to obtain a third mixture; and step S4, sequentially filtering, washing, drying, and calcining the third mixture to obtain rod-shaped nickel oxide material; wherein the pH value of the first mixture is 7.0 to 9.0; and the calcination temperature is 580 to 700°C.

[0024] The rod-shaped nickel oxide material prepared by the method of this application has a rod-like morphology and uniform particle size, which enhances the specific surface energy and surface activity of the rod-shaped nickel oxide material, thereby broadening its applications. Specifically, adding an alkaline solution in step S1 controls the pH value of the first mixture to maintain it within the aforementioned range, forming a slightly alkaline environment. During the growth process, the alkaline environment causes the crystals to preferentially grow along a specific direction, thus forming a rod-shaped structure. At the same time, the adsorption and desorption process of hydroxide ions on the crystal surface affects the surface energy of each crystal facet. Crystal faces with lower surface energy grow at a slower rate, while crystal faces with higher surface energy grow at a faster rate, which is beneficial for better control of the morphology of the nickel oxide material to be rod-shaped and for making the particle size and distribution more uniform. Adding a surfactant in step S2 allows it to adsorb onto the surface of the subsequently generated nickel oxalate precipitate particles to form a protective film, increasing the electrostatic repulsion between particles, thereby improving the dispersion effect and helping the subsequent nickel oxide to form a rod-shaped structure. In step S3, oxalate ions in the oxalate solution react with nickel ions in the nickel salt solution of the second mixture to form nickel oxalate precipitate. Excess liquid in the third mixture is removed by filtration, and impurities on the surface of the nickel oxalate precipitate are removed by washing. Finally, the dried nickel oxalate is calcined to decompose it into nickel oxide. Controlling the calcination temperature within the aforementioned range improves the crystallinity and morphology of the nickel oxide material, promotes the stabilization of the rod-shaped structure, and thus yields pure rod-shaped nickel oxide material. Furthermore, the preparation process of this application is simple, with simple preparation conditions and easy operation, and no harmful gases are generated during the preparation process, thereby reducing the need for tail gas treatment.

[0025] In one embodiment of this application, in step S1 above, a first mixing is performed by a first stirring under ultrasonic conditions, wherein the temperature of the first stirring is 60-90°C, preferably 60-85°C, and the speed of the first stirring is 100-500 r / min, preferably 150-400 r / min.

[0026] Preferably, ultrasonic conditions and controlling the temperature and rotation speed of the first stirring within the aforementioned range help to uniformly disperse the alkaline solution in the nickel salt solution, thereby reducing the possibility of excessively high or low pH in local areas, better controlling the overall pH value of the first mixture, and thus facilitating the formation of rod-shaped nickel oxide with uniform particle size. Simultaneously, ultrasound also helps to obtain rod-shaped nickel oxide powder with a narrow particle size distribution.

[0027] In one embodiment of this application, in step S1 above, the molar concentration of the nickel salt solution, based on nickel ions in the nickel salt solution, is 0.02 to 0.1 mol / L, preferably 0.04 to 0.08 mol / L; the nickel salt solution is selected from any one or more of nickel sulfate solution, nickel chloride solution, and nickel nitrate solution; and / or, the alkaline solution is selected from any one or more of sodium hydroxide solution, potassium hydroxide solution, and ammonia water.

[0028] Preferably controlling the type and molar concentration of the nickel salt solution within the above-mentioned range facilitates the subsequent reaction with the oxalate solution to form nickel oxalate, and also helps to control the morphology and size of the nickel oxide particles. Preferably controlling the type of alkaline solution within the above-mentioned range helps to better adjust the pH of the reaction system, thereby promoting the formation of rod-shaped nickel oxide.

[0029] In one embodiment of this application, in step S2 above, the mass ratio of the surfactant to the first mixture is 0.2 to 5:1000; and / or, the surfactant is a sulfonic acid surfactant and / or a sulfate ester surfactant, preferably a sodium alkylbenzene sulfonate and / or sodium dibutylnaphthalene sulfonate, and preferably a sodium dodecyl sulfate and / or sodium fatty alcohol polyoxyethylene ether sulfate.

[0030] Preferring the type of surfactant and controlling the mass ratio of the surfactant to the first mixture within the above range helps to further improve the dispersion effect, thereby helping the subsequent nickel oxide to form a better rod-shaped structure.

[0031] Step S3 above further includes, preferably, adding the oxalate solution to the second mixture using a peristaltic pump at a propulsion rate of 0.5 to 3 mL / min, followed by a third mixing. More preferably, the propulsion rate is 1 to 2.5 mL / min.

[0032] Using a peristaltic pump and controlling its propulsion speed within the aforementioned range helps to add the oxalate solution to the second mixture at a constant and precise flow rate, thereby helping to maintain pH stability during the reaction process and generate nickel oxalate precipitates with uniform particle size and distribution.

[0033] In one embodiment of this application, in step S3 above, a third mixing is performed by a second stirring. The speed of the second stirring is 100-300 r / min, preferably 150-250 r / min, and the stirring time is 15-120 min, preferably 30-90 min.

[0034] Preferably controlling the speed and time of the second stirring within the above range helps to uniformly mix the oxalate solution and the second mixture, thereby promoting the effective contact and reaction between nickel ions and oxalate ions. At the same time, an appropriate stirring speed helps to maintain the stability and uniformity of the reaction system, thereby helping to obtain nickel oxide with uniform crystal particle size and stable morphology.

[0035] All of the above mixing operations were performed under ultrasonic conditions.

[0036] In one embodiment of this application, in step S3 above, the molar concentration of the oxalate solution, based on the oxalate ions in the oxalate solution, is 0.05–0.6 mol / L, preferably 0.05–0.5 mol / L; the oxalate solution is selected from any one or more of sodium oxalate solution, potassium oxalate solution, and ammonium oxalate solution; and / or, based on the oxalate ions in the oxalate solution and the nickel ions in the nickel salt solution, the molar ratio of the oxalate solution to the nickel salt solution is 0.5–2:1, preferably 1–1.5:1.

[0037] Preferably controlling the molar concentration and type of oxalate solution, as well as the molar ratio of oxalate solution to nickel salt solution within the above range, helps nickel ions and oxalate ions to fully undergo the precipitation reaction, thereby promoting the formation of nickel oxalate precipitate. This results in the subsequent obtaining of nickel oxide material with uniform particle size distribution and rod-shaped morphology. At the same time, it also helps to reduce the formation of non-target products, thereby improving the purity of the product.

[0038] In one embodiment of this application, in step S3 above, the aging reaction temperature is 60-85°C, preferably 60-80°C, and the aging reaction time is 150-200 min, preferably 150-180 min.

[0039] Preferably controlling the temperature and time of the aging reaction within the above range helps to further improve the structure of the nickel oxalate precipitate, thereby facilitating the directional growth of the rod-shaped structure.

[0040] In order to better remove impurities and improve the purity of nickel oxide products, in one embodiment of this application, in step S4 above, the mixture after filtration is washed with water and ethanol respectively.

[0041] In one embodiment of this application, in step S4 above, the drying temperature is 75-120°C, preferably 80-120°C, and the drying time is 180-360 min; and / or, the calcination time is 100-250 min, preferably 120-240 min.

[0042] The preferred drying temperature and time, within the above range, help remove residual solvent after washing, thereby improving the purity of the nickel oxide material obtained after calcination. The preferred calcination time, within the above range, helps promote the complete decomposition of nickel oxalate and the formation of nickel oxide.

[0043] In another typical embodiment of this application, a rod-shaped nickel oxide material is provided, which is prepared by the above-described preparation method, and the D50 particle size of the rod-shaped nickel oxide material is ≤15μm.

[0044] The nickel oxide material prepared by the above preparation method has a rod-like structure, uniform particle size within the above range, which can improve the specific surface energy and surface activity of nickel oxide powder material, thereby broadening the application range of nickel oxide material.

[0045] D50 particle size is the particle size corresponding to the cumulative particle size distribution percentage in the sample reaching 50%.

[0046] The beneficial effects of this application will be further illustrated below with reference to the embodiments.

[0047] Example 1

[0048] Take 200 mL of nickel chloride solution with a nickel ion molar concentration of 0.06 mol / L and place it in a 500 mL reactor. Stir the mixture at 250 r / min under ultrasonic conditions at 70 °C. While stirring, add sodium hydroxide solution dropwise to obtain a first mixture. Adjust the pH of the first mixture to maintain it at 7.0.

[0049] Sodium alkylbenzene sulfonate, a surfactant, is added to the first mixture to form a second mixture, wherein the mass ratio of the surfactant to the first mixture is 5:1000.

[0050] 45 mL of ammonium oxalate solution with a molar concentration of 0.4 mol / L was measured and added dropwise to the second mixture using a peristaltic pump at a feed rate of 1.0 mL / min. Then, the mixture was stirred at 150 r / min for 90 min. After stirring was stopped, the mixture was aged at 70 °C for 180 min to obtain the third mixture.

[0051] The third mixture was sequentially filtered, washed three times with deionized water, and then washed five times with ethanol. The washed mixture was placed in a vacuum drying oven and dried at 80°C for 360 min. The dried mixture was then placed in a crucible and placed in a muffle furnace, where it was calcined at 650°C for 200 min and cooled with the furnace to obtain rod-shaped nickel oxide material. This rod-shaped nickel oxide material is a fine rod-shaped nickel oxide powder with a predominantly rod-shaped structure. Its SEM image is shown below. Figure 1 As shown.

[0052] Example 2

[0053] Take 150 mL of nickel chloride solution with a nickel ion molar concentration of 0.02 mol / L and place it in a 500 mL reactor. Stir the mixture at 200 r / min under ultrasonic conditions at 60 °C. While stirring, add sodium hydroxide solution dropwise to obtain a first mixture and adjust the pH of the first mixture to maintain it at 7.0.

[0054] Sodium alkylbenzene sulfonate, a surfactant, is added to the first mixture to form a second mixture, wherein the mass ratio of the surfactant to the first mixture is 0.2:1000.

[0055] 120 mL of ammonium oxalate solution with a molar concentration of 0.05 mol / L was measured and added dropwise to the second mixture using a peristaltic pump at a rate of 1.5 mL / min. Then, the mixture was stirred at 150 r / min for 30 min. After stirring was stopped, the mixture was aged at 60 °C for 180 min to obtain the third mixture.

[0056] After filtering the third mixture, it was washed three times with deionized water and then five times with ethanol. The washed mixture was placed in a vacuum drying oven and dried at 100°C for 300 min. The dried mixture was then placed in a crucible and placed in a muffle furnace and calcined at 600°C for 240 min, followed by furnace cooling to obtain rod-shaped nickel oxide material, which is a rod-shaped fine nickel oxide powder material.

[0057] Example 3

[0058] Take 150 mL of nickel chloride solution with a nickel ion molar concentration of 0.04 mol / L and place it in a 500 mL reactor. Stir the mixture at 300 r / min under ultrasonic conditions at 85 °C. While stirring, add sodium hydroxide solution dropwise to obtain a first mixture and adjust the pH of the first mixture to maintain it at 8.5.

[0059] Sodium alkylbenzene sulfonate, a surfactant, is added to the first mixture to form a second mixture, wherein the mass ratio of the surfactant to the first mixture is 3:1000.

[0060] 36 mL of sodium oxalate solution with a molar concentration of 0.25 mol / L was measured and added dropwise to the second mixture using a peristaltic pump at a feed rate of 2.0 mL / min. Then, the mixture was stirred at 150 r / min for 60 min. After stirring was stopped, the mixture was aged at 85 °C for 150 min to obtain the third mixture.

[0061] The third mixture was filtered sequentially, washed three times with deionized water, and then washed five times with ethanol. The washed mixture was placed in a vacuum drying oven and dried at 120°C for 180 min. The dried mixture was then placed in a crucible and placed in a muffle furnace, where it was calcined at 680°C for 120 min and cooled with the furnace to obtain rod-shaped nickel oxide material. This rod-shaped nickel oxide material is a fine rod-shaped nickel oxide powder with a D50 particle size ≤10 μm. Its morphology is mainly rod-shaped, with a certain amount of fine, amorphous structures.

[0062] Example 4

[0063] The difference from Example 1 is that the pH value of the first mixture is 9.0, and rod-shaped nickel oxide material is finally obtained.

[0064] Example 5

[0065] The difference from Example 1 is that the calcination temperature is 580°C, and rod-shaped nickel oxide material is finally obtained.

[0066] Example 6

[0067] The difference from Example 1 is that the mass ratio of surfactant to the first mixture is 0.2:1000, and rod-shaped nickel oxide material is finally obtained.

[0068] Example 7

[0069] The difference from Example 1 is that the mass ratio of surfactant to the first mixture is 10:1000, and rod-shaped nickel oxide material is finally obtained.

[0070] Example 8

[0071] The difference from Example 1 is that the volume of the nickel salt solution is 150 mL and the molar concentration is 0.1 mol / L, and the volume of the oxalate solution is 120 mL and the molar concentration is 0.25 mol / L, so that the molar ratio of oxalate ions to nickel ions in the second mixture is 2:1, and finally rod-shaped nickel oxide material is obtained.

[0072] Example 9

[0073] The difference from Example 1 is that the volume of the nickel salt solution is 150 mL and the molar concentration is 0.02 mol / L, and the volume of the oxalate solution is 15 mL and the molar concentration is 0.6 mol / L, so that the molar ratio of oxalate ions to nickel ions in the second mixture is 3:1, and finally rod-shaped nickel oxide material is obtained.

[0074] Example 10

[0075] The difference from Example 1 is that the oxalate solution was added dropwise to the second mixture using a peristaltic pump at a rate of 3 mL / min, followed by a second stirring at 300 r / min for 15 min. After stirring was stopped, the mixture was aged at 60°C for 180 min to obtain the third mixture, and finally rod-shaped nickel oxide material was obtained.

[0076] Example 11

[0077] The difference from Example 1 is that the oxalate solution was added dropwise to the second mixture using a peristaltic pump at a rate of 4 mL / min, followed by a second stirring at 50 r / min for 150 min. After stirring was stopped, the mixture was aged at 60°C for 180 min to obtain the third mixture, and finally rod-shaped nickel oxide material was obtained.

[0078] Example 12

[0079] The difference from Example 1 is that the temperature of the first stirring is 85°C, the temperature of the aging reaction is 85°C, the aging reaction time is 200 min, and finally rod-shaped nickel oxide material is obtained.

[0080] Example 13

[0081] The difference from Example 1 is that the temperature of the first stirring is 95°C, the temperature of the aging reaction is 95°C, the aging reaction time is 125 min, and finally rod-shaped nickel oxide material is obtained.

[0082] Comparative Example 1

[0083] The difference from Example 1 is that the pH value of the first mixture is 6.0, resulting in rod-shaped nickel oxide material. SEM images show that its morphology is rod-shaped, with many fine, amorphous structures, such as... Figure 2 As shown.

[0084] Comparative Example 2

[0085] The difference from Example 1 is that the calcination temperature is 500°C, and rod-shaped nickel oxide material is finally obtained.

[0086] Test method:

[0087] D50 particle size determination: The particle size distribution of the material was detected using a laser particle size analyzer.

[0088] Specific surface area determination: The specific surface area of ​​the material is measured using a specific surface area meter.

[0089] The nickel oxide materials of the above embodiments and comparative examples were subjected to performance tests, and the test results are shown in Table 1.

[0090] Table 1

[0091]

[0092] In the embodiment, the rod-shaped nickel oxide material is mainly rod-shaped with uniform particle size, while the nickel oxide material in the comparative example has fewer rod-shaped structures and contains more fine and irregular nickel oxide particles.

[0093] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0094] The rod-shaped nickel oxide material prepared by the method of this application has a rod-like morphology and uniform particle size, which enhances the specific surface energy and surface activity of the rod-shaped nickel oxide material, thereby broadening its applications. Specifically, adding an alkaline solution in step S1 controls the pH value of the first mixture to maintain it within the aforementioned range, forming a slightly alkaline environment. During the growth process, the alkaline environment causes the crystals to preferentially grow along a specific direction, thus forming a rod-shaped structure. At the same time, the adsorption and desorption process of hydroxide ions on the crystal surface affects the surface energy of each crystal facet. Crystal faces with lower surface energy grow at a slower rate, while crystal faces with higher surface energy grow at a faster rate, which is beneficial for better control of the morphology of the nickel oxide material to be rod-shaped and for making the particle size and distribution more uniform. Adding a surfactant in step S2 allows it to adsorb onto the surface of the subsequently generated nickel oxalate precipitate particles to form a protective film, increasing the electrostatic repulsion between particles, thereby improving the dispersion effect and helping the subsequent nickel oxide to form a rod-shaped structure. In step S3, oxalate ions in the oxalate solution react with nickel ions in the nickel salt solution of the second mixture to form nickel oxalate precipitate. Excess liquid in the third mixture is removed by filtration, and impurities on the surface of the nickel oxalate precipitate are removed by washing. Finally, the dried nickel oxalate is calcined to decompose it into nickel oxide. Controlling the calcination temperature within the aforementioned range improves the crystallinity and morphology of the nickel oxide material, promotes the stabilization of the rod-shaped structure, and thus yields pure rod-shaped nickel oxide material. Furthermore, the preparation process of this application is simple, with simple preparation conditions and easy operation, and no harmful gases are generated during the preparation process, thereby reducing the need for tail gas treatment.

[0095] The above are merely embodiments of the present invention and are not intended to limit the invention. Those skilled in the art will recognize that the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing rod-shaped nickel oxide material, characterized in that, The preparation method includes: Step S1: The raw materials, including nickel salt solution and alkaline solution, are first mixed to obtain a first mixture; Step S2: The first mixture and the surfactant raw material are mixed in a second mixture to obtain a second mixture; Step S3 involves sequentially subjecting the raw materials, including the second mixture and the oxalate solution, to a third mixing and aging reaction to obtain a third mixture; and Step S4: The third mixture is sequentially filtered, washed, dried and calcined to obtain rod-shaped nickel oxide material; The first mixture has a pH value of 7.0 to 9.0; the calcination temperature is 580 to 700°C. In step S1, the molar concentration of the nickel salt solution is 0.02~0.1 mol / L, based on the nickel ions in the nickel salt solution; the nickel salt solution is selected from any one or more of nickel sulfate solution, nickel chloride solution, and nickel nitrate solution; the alkaline solution is selected from any one or more of sodium hydroxide solution, potassium hydroxide solution, and ammonia water. In step S2, the mass ratio of the surfactant to the first mixture is 0.2~5:1000; the surfactant is a sulfonic acid surfactant and / or a sulfate ester surfactant. In step S3, the molar concentration of the oxalate solution is 0.05~0.6 mol / L, based on the oxalate ions in the oxalate solution; the oxalate solution is selected from any one or more of sodium oxalate solution, potassium oxalate solution, and ammonium oxalate solution. The molar ratio of the oxalate solution to the nickel salt solution is 0.5 to 2:1, based on the oxalate ions in the oxalate solution and the nickel ions in the nickel salt solution.

2. The preparation method according to claim 1, characterized in that, In step S1, the first mixing is carried out under ultrasonic conditions by first stirring, wherein the temperature of the first stirring is 60~90℃ and the speed of the first stirring is 100~500r / min.

3. The preparation method according to claim 1 or 2, characterized in that, In step S3, the third mixing is carried out by a second stirring, wherein the stirring speed of the second stirring is 100~300 r / min and the stirring time is 15~120 min.

4. The preparation method according to claim 1 or 2, characterized in that, In step S3, the aging reaction temperature is 60~85℃, and the aging reaction time is 150~200min.

5. The preparation method according to claim 1 or 2, characterized in that, In step S4, the filtered mixture is washed sequentially with water and ethanol.

6. The preparation method according to claim 1 or 2, characterized in that, In step S4, the drying temperature is 75~120℃, the drying time is 180~360min; and / or, the calcination time is 100~250min.

7. A rod-shaped nickel oxide material, characterized in that, The rod-shaped nickel oxide material is prepared by the preparation method according to any one of claims 1 to 6, and the D50 particle size is ≤15μm.

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