Cobaltosic oxide powder and preparation method and application thereof
By using ammonium bicarbonate as a precipitant in the cobalt salt solution, the reaction conditions and calcination process were controlled, and high-purity nano-scale cobalt tetroxide powder was prepared, which solved the problems of large particle size and low specific surface area in the traditional method, and achieved low cost and efficient preparation of nanomaterials.
Patent Information
- Application Number
- CN202510513838.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-23
- Publication Date
- 2025-07-29
AI Technical Summary
The existing preparation methods are complex, resulting in large size of Co3O4 particles and low specific surface area, which affects electrochemical performance and catalytic activity, and has problems of high energy consumption and high cost.
Ammonium bicarbonate was used as the precipitant and a cobalt salt solution was injected into the reactor at 20-35°C to control the feed rate and stirring time of the reaction solution, and then step-up heating and calcining were performed to prepare a tricobalt tetroxide powder with D50 < 0.2 μm, Dmax less than 2 μm, and particle size consistency < 0.9.
The preparation of tricobalt tetroxide powder with high purity, nanoscale and monodispersity is achieved, reducing the reaction temperature and cost, avoiding particle agglomeration, and improving electrochemical performance and catalytic activity.
Smart Images
Figure CN120383340A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of cobalt tetroxide preparation, and more specifically, to cobalt tetroxide powder and its preparation method and application. Background Art
[0002] Nano-Co3O4 is a p-type semiconductor material with excellent electrochemical activity, catalytic performance and thermal stability, and is widely used in energy storage (such as lithium-ion batteries, supercapacitors), catalytic oxidation reactions (such as VOCs degradation), gas sensing (such as CO detection) and other fields.
[0003] Co3O4 particles synthesized by traditional preparation methods (such as solid-phase method, sol-gel method) have large particle sizes and low specific surface areas, resulting in limited electrochemical performance. Nano-scale Co3O4 is prone to agglomeration, affecting catalytic activity and cycle stability. Existing processes have high energy consumption and complex steps, making it difficult to achieve large-scale production.
[0004] The existing preparation methods of cobalt trioxide have the following problems: the preparation method is complex, and surfactants are used to ensure uniform particle dispersion, which will increase the cost and difficulty of wastewater treatment; using sodium hydroxide as a precipitant will increase the washing cost or affect the purity of the obtained product; or, the obtained cobalt tetroxide still has poor dispersibility, and agglomeration is likely to occur, resulting in larger local particle sizes.
[0005] In view of this, the present invention is specifically proposed. Summary of the Invention
[0006] The purpose of the present invention is to provide cobalt tetroxide powder and its preparation method and application, aiming to improve at least one of the problems mentioned in the background art.
[0007] The present invention is implemented as follows:
[0008] In the first aspect, the present invention provides a cobalt tetroxide powder with D50 < 0.2 μm, Dmax less than 2 μm, particle size consistency < 0.9, and BET of 21.4 - 29.1 m 2 / g.
[0009] In the second aspect, the present invention provides a preparation method of cobalt tetroxide powder, including:
[0010] Providing a cobalt salt solution, wherein the concentration of cobalt ions in the cobalt salt solution is 120 - 130 g / L;
[0011] Injecting the cobalt salt solution into a reaction kettle with a bottom liquid at 20 - 35 °C under continuous stirring; the feeding speed of the cobalt salt solution and the volume ratio of the reaction kettle is 20 - 30 L / min:100 L;
[0012] After the injection of the cobalt salt solution is completed, continuously stir and react for 8-15 minutes to fully precipitate cobalt carbonate to obtain a slurry;
[0013] Extract cobalt carbonate from the slurry;
[0014] Calcine the cobalt carbonate to obtain cobalt tetroxide. The calcination conditions are as follows: in an oxygen environment, calcine at 300-400 °C for 2-5 hours, and then raise the temperature to 500-700 °C and calcine for 2-4 hours.
[0015] In an alternative embodiment, before injecting the cobalt salt solution into the reaction kettle, first prepare a bottom liquid in the reaction kettle;
[0016] The bottom liquid is obtained by mixing deionized water and ammonium bicarbonate solution;
[0017] The concentration of the ammonium bicarbonate solution is 150-250 g / L, the deionized water accounts for 30-60% of the volume of the reaction kettle, and the volume ratio of the cobalt salt solution to the ammonium bicarbonate solution is 1:1-1.5.
[0018] In an alternative embodiment, the stirring speed in the reaction kettle is 500-600 r / min.
[0019] In an alternative embodiment, the calcination conditions are specifically as follows: raise the temperature to 300-400 °C at a rate of 2-5 °C / min and calcine for 2-5 hours, and then raise the temperature to 500-700 °C at a rate of 2-5 °C / min and calcine for 2-4 hours.
[0020] In an alternative embodiment, the solute in the cobalt salt is at least one of cobalt chloride and cobalt sulfate.
[0021] In an alternative embodiment, the method for extracting solid substances from the slurry includes:
[0022] Perform solid-liquid separation on the slurry, wash the separated solid, and obtain cobalt carbonate after drying.
[0023] In an alternative embodiment, the drying temperature is 80-120 °C.
[0024] In a third aspect, the present invention provides the application of cobalt tetroxide powder prepared by the cobalt tetroxide powder or the preparation method according to any one of the foregoing embodiments in the fields of energy storage, catalytic oxidation or gas sensing.
[0025] The present invention has the following beneficial effects:
[0026] The cobalt tetroxide powder provided by the present invention is nanoscale, has high purity and good monodispersity.
[0027] The preparation method provided by the present invention uses ammonium bicarbonate as a precipitant, sets appropriate reaction solution concentrations, reaction solution injection flow rates, sets an appropriate reaction time after the reaction solution is added, and sets appropriate calcination conditions after extracting cobalt carbonate, so as to prepare cobalt tetroxide with high purity, nanoscale and good dispersibility. This method is simple, has a low reaction temperature, low cost and is environmentally friendly. Using ammonium bicarbonate as a precipitant can well avoid introducing impurities during the preparation process, and ammonium bicarbonate with an appropriate concentration can make the reaction rate controllable, which helps to obtain nanoscale materials; reacting at 20-35 °C can ensure that the reaction proceeds at a verified rate, effectively avoiding too fast particle growth and particle agglomeration; an appropriate feeding speed also helps to obtain nanoscale materials with good dispersibility; after the reaction solution is added, an appropriate stirring time can ensure sufficient reaction and avoid too large particle growth, ensuring that the finally obtained materials are nanoscale; the calcination is carried out by stepwise heating. Compared with direct high-temperature calcination, it can well avoid product melting and bonding and particle agglomeration, thereby ensuring the preparation of nanoscale cobalt tetroxide with good dispersibility. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.
[0029] Figures 1 to 6 They are SEM images of cobalt tetroxide prepared in Examples 1 to 6 in sequence;
[0030] Figure 7 and Figure 8 They are SEM images of cobalt tetroxide prepared in Comparative Example 1 and Comparative Example 2 respectively. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0031] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Those not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or instruments not specified by the manufacturer are all conventional products that can be obtained through commercial purchase.
[0032] The following further describes the features and performance of the present invention in detail with reference to the embodiments.
[0033] A cobalt tetroxide powder provided by an embodiment of the present invention has D50 < 0.2 μm, Dmax less than 2 μm, particle size uniformity < 0.9, and BET is 21.4-29.1 m 2 / g.
[0034] The cobalt tetroxide powder provided by the embodiment of the present invention is nanoscale, with high purity and good monodispersity.
[0035] A preparation method of a cobalt tetroxide powder provided by the embodiment of the present invention includes:
[0036] Providing a cobalt salt solution, wherein the concentration of cobalt ions in the cobalt salt solution is 120 - 130 g / L (for example, 120 g / L, 125 g / L or 130 g / L);
[0037] Injecting the cobalt salt solution into a reaction kettle with a bottom liquid under the conditions of 20 - 35 °C (for example, 20 °C, 25 °C, 30 °C or 35 °C) and continuous stirring; the volume ratio of the feeding speed of the cobalt salt solution to the volume of the reaction kettle is 20 - 30 L / min:100 L (for example, 20 L / min:100 L, 25 L / min:100 L or 30 L / min:100 L);
[0038] After the injection of the cobalt salt solution is completed, continuously stir and react for 8 - 15 min (for example, 8 min, 10 min, 13 min or 15 min) to fully precipitate cobalt carbonate to obtain a slurry;
[0039] Extracting cobalt carbonate from the slurry;
[0040] Calcinating the cobalt carbonate to obtain cobalt tetroxide, and the calcination conditions are in an oxygen environment (air atmosphere or oxygen atmosphere), calcining at 300 - 400 °C (for example, 300 °C, 350 °C or 400 °C) for 2 - 5 h (for example, 2 h, 3 h or 5 h), and then heating up to 500 - 700 °C (for example, 500 °C, 600 °C or 700 °C) and calcining for 2 - 4 h (for example, 2 h, 3 h or 4 h).
[0041] The preparation method provided by the present invention realizes the preparation of cobalt tetroxide with high purity, nanoscale and good dispersibility by using ammonium bicarbonate as a precipitant, setting appropriate reaction solution concentration, reaction solution injection flow rate, setting appropriate reaction time after the reaction solution is added, and setting appropriate calcination conditions after extracting cobalt carbonate. This method is simple, has a low reaction temperature, low cost and is environmentally friendly. Using ammonium bicarbonate as a precipitant can well avoid introducing impurities during the preparation process, and ammonium bicarbonate with an appropriate concentration can make the reaction rate controllable, which helps to obtain nanoscale materials; reacting at 20-35°C can ensure that the reaction proceeds at a verified rate, effectively avoiding too fast particle growth and particle agglomeration; an appropriate feeding speed also helps to obtain nanoscale materials with good dispersibility; after the reaction solution is added, an appropriate stirring time can ensure sufficient reaction and avoid too large particle growth, ensuring that the finally obtained materials are nanoscale; the calcination is carried out in a stepwise heating manner. Compared with direct high-temperature calcination, it can well avoid product melting and bonding and particle agglomeration, thus ensuring the preparation of nanoscale cobalt tetroxide with good dispersibility.
[0042] Optionally, before injecting the cobalt salt solution into the reaction kettle, a bottom liquid is first prepared in the reaction kettle;
[0043] The bottom liquid is obtained by mixing deionized water and an ammonium bicarbonate solution;
[0044] The concentration of the ammonium bicarbonate solution is 150-250 g / L (such as 150 g / L, 200 g / L or 250 g / L), the deionized water accounts for 30-60% (such as 30%, 40%, 50% or 60%) of the volume of the reaction kettle, and the volume ratio of the cobalt salt solution to the ammonium bicarbonate solution is 1:1-1.5 (such as 1:1, 1:1.3 or 1:1.5).
[0045] Optionally, the stirring speed in the reaction kettle is 500-600 r / min (such as 500 r / min, 550 r / min or 600 r / min).
[0046] Optionally, to further ensure that the obtained materials do not agglomerate, the calcination conditions are specifically heating at 2-5°C / min (such as 2°C / min, 3°C / min or 5°C / min) to 300-400°C (such as 300°C, 350°C or 400°C) for calcination for 2-5 h (such as 2 h, 3 h or 5 h), and then heating at 2-5°C / min (such as 2°C / min, 3°C / min or 5°C / min) to 500-700°C (such as 500°C, 600°C or 700°C) for calcination for 2-4 h (such as 2 h, 3 h or 4 h).
[0047] Optionally, the solute in the cobalt salt is at least one of cobalt chloride and cobalt sulfate.
[0048] Optionally, the method for extracting solid substances from the slurry includes:
[0049] Performing solid-liquid separation on the slurry, washing the separated solid, and obtaining cobalt carbonate after drying.
[0050] Furthermore, the solid-liquid separation method can be centrifugation or filtration, and the detergent used for washing is deionized water.
[0051] Optionally, the drying temperature is 80 - 120 °C (for example, 80 °C, 100 °C, or 120 °C).
[0052] The cobalt tetroxide powder provided in the embodiments of the present invention or the cobalt tetroxide powder prepared by the preparation method has good dispersibility due to being nanoscale, so good effects can be achieved when it is applied in the fields of energy storage, catalytic oxidation, or gas sensing.
[0053] Example 1
[0054] Providing a cobalt salt solution (cobalt chloride solution), the concentration of cobalt ions in the cobalt salt solution is 120 g / L;
[0055] Providing an ammonium bicarbonate solution, the concentration of the ammonium bicarbonate solution is 200 g / L;
[0056] The volume ratio of the cobalt salt solution injected into the reaction kettle to the ammonium bicarbonate solution is 1:1;
[0057] Providing a 100 L reaction kettle, there is 50% deionized water in the solvent of the reaction kettle, and injecting 15 L of ammonium bicarbonate solution into the reaction kettle and mixing evenly to form a bottom liquid;
[0058] Injecting 15 L of cobalt salt solution into the reaction kettle under the condition of continuous stirring at 600 r / min; the feeding rate of the cobalt salt solution is 20 L / min;
[0059] After the injection of the cobalt salt solution is completed, continuously stir and react for 10 min to fully precipitate cobalt carbonate to obtain a slurry;
[0060] Extracting cobalt carbonate from the slurry;
[0061] Calcining the cobalt carbonate to obtain cobalt tetroxide, the calcining conditions are: in an air atmosphere, heating to 350 °C at a rate of 5 °C / min and calcining for 3 h, and then heating to 600 °C at a rate of 5 °C / min and calcining for 3 h. The obtained cobalt tetroxide is as Figure 1 shown, and it can be seen that it has better dispersibility.
[0062] Example 2
[0063] This example is basically the same as Example 1, except that: the volume ratio of the cobalt salt solution to the ammonium bicarbonate solution injected into the reaction kettle is 1:2. The prepared cobalt tetroxide is as Figure 2 shown, and it can be seen that it has better dispersibility.
[0064] Example 3
[0065] This example is basically the same as Example 1, except that: the feeding rate of the cobalt salt solution is 5 L / min. The prepared cobalt tetroxide is as Figure 3 shown, and it can be seen that it has better dispersibility.
[0066] Example 4
[0067] This example is basically the same as Example 1, except that: the concentration of the cobalt salt solution is 130 g / L and the feeding rate is 5 L / min. The prepared cobalt tetroxide is as Figure 4 shown, and it can be seen that it has better dispersibility, but slightly worse than that of Example 1.
[0068] Example 5
[0069] This example is basically the same as Example 1, except that: the concentration of the cobalt salt solution is 130 g / L and the stirring speed is 300 r / min. The prepared cobalt tetroxide is as Figure 5 shown, and it can be seen that it has better dispersibility, but slightly worse than that of Example 1.
[0070] Example 6
[0071] This example is basically the same as Example 1, except that: the cobalt salt solution is cobalt sulfate solution and the concentration of the cobalt salt solution is 130 g / L. The prepared cobalt tetroxide is as Figure 6 shown, and it can be seen that it has better dispersibility.
[0072] Example 7
[0073] This example is basically the same as Example 1, except that: the reaction temperature is 35 °C.
[0074] Example 8
[0075] This example is basically the same as Example 5, except that: the stirring speed is 500 r / min.
[0076] Example 9
[0077] This example is basically the same as Example 1, except that: the concentration of the cobalt salt solution is 130 g / L. After the injection of the reaction solution is completed, the reaction is continuously stirred for 8 min.
[0078] Example 10
[0079] This example is basically the same as Example 1, except that: the concentration of the cobalt salt solution is 130 g / L, and after the injection of the reaction solution is completed, the reaction is continuously stirred for 15 min.
[0080] Example 11
[0081] This example is basically the same as Example 1, except that: the feeding rate of the cobalt salt solution is 30 L / min.
[0082] Example 12
[0083] This example is basically the same as Example 1, except that: the volume ratio of the cobalt salt solution injected into the reaction kettle to the ammonium bicarbonate solution is 1:1.5.
[0084] Comparative Example 1
[0085] This comparative example is basically the same as Example 1, except that: the reaction temperature is 45 °C. The prepared cobalt tetroxide is as Figure 7 shown, and it can be seen that its dispersibility is poor.
[0086] Comparative Example 2
[0087] This comparative example is basically the same as Example 10, except that: the reaction time is 60 min. The prepared cobalt tetroxide is as Figure 8 shown, and its dispersibility is significantly poor.
[0088] Experimental Example
[0089] Test the BET of the cobalt tetroxide prepared in each example and comparative example, and measure D50, Dmax and particle size consistency using a Malvern laser particle size analyzer.
[0090] The specific test method is that BET is measured by the static volumetric method, and the particle size is measured by the dynamic light scattering method.
[0091] Record the test results in Table 1.
[0092] Table 1 Performance test results of cobalt tetroxide prepared in each example and comparative example
[0093]
[0094]
[0095] It can be seen from Table 1 that the cobalt tetroxide prepared in each example has a large BET, a small particle size, and good consistency, indicating that it has good dispersibility;
[0096] Comparing Comparative Example 1 with Example 1 and Example 7, its BET value is significantly lower and the particle size is larger, indicating that during the precipitation process of cobalt carbonate, powders with larger BET and better dispersibility can be obtained within the temperature reaction range provided by the present invention;
[0097] Comparing Comparative Example 2 with Example 10, the BET value of Comparative Example 2 is significantly lower, indicating that the reaction time should not be too long, and the cobalt tetroxide powder prepared within the reaction time required by the present invention has better dispersibility;
[0098] Comparing Example 2 with Example 1 and Example 12, the BET of Example 1 and Example 12 is slightly higher than that of Example 2, indicating that the BET of cobalt tetroxide prepared when the volume ratio of cobalt salt solution to ammonium bicarbonate solution is 1:1 to 1.5 is larger;
[0099] Comparing Example 3 with Example 1 and Example 11, the BET of Example 3 is slightly smaller than that of Example 1 and Example 11, indicating that if the injection flow rate of the reaction solution during the reaction process is too low, the obtained BET will be larger, and a product with a larger BET value can be obtained when it is within the range of 20 - 30 L / min required by the present invention;
[0100] Comparing Example 5 with Example 8, the BET of Example 5 is slightly smaller than that of Example 8, indicating that if the stirring speed during the reaction process is too low, the obtained BET will be larger, and a product with a larger BET value can be obtained when it is within the range of 500 - 600 r / min required by the present invention.
[0101] In summary, for the preparation method provided by the present invention, by using ammonium bicarbonate as a precipitating agent, setting appropriate reaction solution concentration, reaction solution injection flow rate, setting an appropriate reaction time after the reaction solution is added, and setting appropriate calcination conditions after extracting cobalt carbonate, cobalt tetroxide with high purity, nanoscale and good dispersibility can be prepared. This method is simple, has a low reaction temperature, low cost, and is environmentally friendly.
[0102] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. A cobalt tetroxide powder, characterized in that, D50 < 0.2 μm, Dmax is less than 2 μm, particle size consistency < 0.9, BET is 21.4 - 29.1 m 2 / g.
2. A method for preparing cobalt tetroxide powder, characterized in that, Including: Providing a cobalt salt solution, wherein the concentration of cobalt ions in the cobalt salt solution is 120 - 130 g / L; Injecting the cobalt salt solution into a reaction kettle with a bottom liquid under the conditions of 20 - 35 °C and continuous stirring; the volume ratio of the feeding rate of the cobalt salt solution to the volume of the reaction kettle is 20 - 30 L / min:100 L; After the injection of the cobalt salt solution is completed, continuously stir and react for 8 - 15 min to fully precipitate cobalt carbonate to obtain a slurry; Extracting cobalt carbonate from the slurry; Calcining the cobalt carbonate to obtain cobalt tetroxide, and the calcining conditions are calcining at 300 - 400 °C for 2 - 5 h in an oxygen environment, and then heating to 500 - 700 °C and calcining for 2 - 4 h.
3. The preparation method according to claim 2, wherein Before injecting the cobalt salt solution into the reaction kettle, first prepare a bottom liquid in the reaction kettle; The bottom liquid is obtained by mixing deionized water and an ammonium bicarbonate solution; The concentration of the ammonium bicarbonate solution is 150 - 250 g / L, the deionized water accounts for 30 - 60% of the volume of the reaction kettle, and the volume ratio of the cobalt salt solution to the ammonium bicarbonate solution is 1:1 - 1.
5.
4. The preparation method according to claim 2, wherein The stirring speed in the reaction kettle is 500 - 600 r / min.
5. The preparation method according to claim 2, wherein The calcining conditions are specifically heating to 300 - 400 °C at 2 - 5 °C / min and calcining for 2 - 5 h, and then heating to 500 - 700 °C at 2 - 5 °C / min and calcining for 2 - 4 h.
6. The preparation method according to claim 2, characterized in that, The solute in the cobalt salt is at least one of cobalt chloride and cobalt sulfate.
7. The preparation method according to any one of claims 2 to 6, characterized in that, The method for extracting solid substances from the slurry includes: Performing solid-liquid separation on the slurry, washing the separated solid, and obtaining cobalt carbonate after drying.
8. The preparation method according to claim 7, wherein The drying temperature is 80 - 120 °C.
9. The application of the cobalt tetroxide powder as described in claim 1 or the cobalt tetroxide powder prepared by the preparation method as described in any one of claims 2 - 8 in the fields of energy storage, catalytic oxidation or gas sensing.