Metal-doped cobaltosic oxide nano-chain catalytic material and preparation method thereof
The preparation of metal-doped cobalt tetraoxide nanochain catalytic materials through hydrothermal method and high-temperature calcination solves the problems of high preparation costs and complex morphology in the prior art, achieves low-cost large-scale preparation and electrochemical performance improvement, and is suitable for hydrogen production by electrolyzing water.
Patent Information
- Application Number
- CN202311873853.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-29
- Publication Date
- 2025-07-22
AI Technical Summary
There is a lack of simple and low-cost methods in the prior art to prepare Co3O4-based electrocatalysts with specific doping elements and special morphology, resulting in limited application in the field of electrolyzed hydrogen production.
Using cobalt nitrate and metal salt as raw materials, ethanol and water as solvents, and urea as reducing agents, metal-doped basic cobalt carbonate nanowire materials are prepared by hydrothermal method, and calcined at high temperature to form metal-doped cobalt tetraoxide nanochain catalytic material.
It realizes a simple, fast and low-cost large-scale preparation of metal-doped cobalt tetraoxide nanochain catalytic materials, with a novel structure and enhanced electrochemical performance, and is suitable for hydrogen production in water electrolysis.
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Figure CN120348975A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of the preparation of nano-catalytic materials, and particularly relates to a metal-doped cobalt tetroxide nano-chain catalytic material and a preparation method thereof. Background Art
[0002] Hydrogen energy has the advantages of high energy density, clean combustion products, etc. The electrolytic hydrogen production technology is the key to realizing green hydrogen production, and its key core is to develop advanced catalyst materials. Noble metal platinum is a landmark catalyst for hydrogen evolution reaction (HER) in water electrolysis, but its low reserves and easy dissolution during the working process limit the development of electrolytic hydrogen production technology. Co3O4 has mutually convertible Co 2+ tetrahedra and Co 3+ octahedra, and is a recognized potential candidate to replace platinum catalysts, but the strong adsorption / desorption of hydrogen on the surface of Co3O4 leads to a high HER potential. Modulating the surface structure of Co3O4 by heteroatom doping to affect its intrinsic activity has been proven effective and has been widely studied.
[0003] Currently, CN115845863A introduces a preparation method of a chromium-doped cobalt tetroxide photocatalyst, CN115101744A introduces a preparation method of an iron-doped cobalt tetroxide, CN113295737B introduces a preparation method of a manganese-doped cobalt tetroxide porous nano-sheet material, and CN112010354A introduces a preparation method of a titanium-doped cobalt tetroxide. However, there are not many technologies for preparing metal-doped Co3O4 nano-materials with specific doping elements and special morphologies. In addition, in the prior art, different preparation processes usually need to be designed according to different doping elements, and the processes required to generate special morphologies are complex and costly. Therefore, developing a simple process to synthesize metal-doped Co3O4 nano-materials with specific doping elements and special morphologies is of great significance for the development of Co3O4-based electrocatalysts. Summary of the Invention
[0004] The purpose of the present invention is to overcome the above-mentioned disadvantages of the prior art, and provide a metal-doped cobalt tetroxide nano-chain catalytic material and a preparation method thereof, so as to solve the lack of Co3O4-based electrocatalysts with specific doping elements and special morphologies in the prior art.
[0005] To achieve the above purpose, the present invention adopts the following technical solutions:
[0006] A preparation method of a metal-doped cobalt tetroxide nano-chain catalytic material, comprising the following steps:
[0007] Step 1: Cobalt nitrate and metal salts are added to a mixed solvent of ethanol and water. After stirring until completely dissolved, urea is added to obtain a mixed solution. The mixed mass ratio of cobalt nitrate, metal salts, and urea is (200 - 400):(10 - 200):(500 - 1800). After the mixed solution undergoes a hydrothermal reaction, the hydrothermal reaction product is centrifuged, washed, and dried to obtain nanowire-like metal-doped basic cobalt carbonate.
[0008] Step 2: The nanowire-like metal-doped basic cobalt carbonate is placed in a crucible and calcined in a high-temperature air atmosphere to obtain chain-like metal-doped cobalt tetroxide.
[0009] A further improvement of the present invention lies in:
[0010] Preferably, in Step 1, the volume ratio of ethanol to water is 1:1.
[0011] Preferably, in Step 1, the ratio of cobalt nitrate to the mixed solvent is: (200 - 400) mg: 30 mL.
[0012] Preferably, in Step 1, the added metal salts are one or a mixture of copper acetate, zinc sulfate, copper acetate, zinc sulfate, ammonium metavanadate, iridium acetate, manganese acetate, or nickel acetate.
[0013] Preferably, in Step 1, the hydrothermal reaction temperature is 110 - 130 °C, and the hydrothermal reaction time is 120 - 240 min.
[0014] Preferably, in Step 1, the centrifugation speed is 1000 rmp, and the centrifugation time is 10 min.
[0015] Preferably, in Step 1, the drying time is 2 - 4 h.
[0016] Preferably, in Step 2, the calcination temperature is 350 - 400 °C, and the calcination time is 30 - 90 min.
[0017] A metal-doped cobalt tetroxide nanorod catalytic material prepared by any one of the above preparation methods.
[0018] Compared with the prior art, the present invention has the following beneficial effects:
[0019] The present invention discloses a preparation method of a metal-doped cobalt tetroxide nano-chain catalytic material. In this process, cobalt nitrate and metal salts are used as raw materials, urea is used as a reducing agent, and a mixed solution of ethanol and water is used as a solvent. First, a metal-doped basic cobalt carbonate nanowire material is prepared by a hydrothermal method, and then it is subjected to high-temperature oxidation annealing. During the annealing process, the metal-doped basic cobalt carbonate decomposes to generate metal-doped cobalt oxide, H2O, and CO2. At the same time, it is found that the morphology of the nanowires changes to form nano-chains during the high-temperature process, obtaining a metal-doped cobalt tetroxide nano-chain catalytic material. This preparation process is simple, fast, low-cost, and highly efficient, and is suitable for large-scale preparation. Moreover, the obtained metal-doped cobalt tetroxide nano-chain catalytic material has a novel structure and is expected to be applied in fields such as electrolytic water hydrogen production.
[0020] The present invention also discloses a metal-doped cobalt tetroxide nano-chain catalytic material. The doped metal M can be other transition metals except Co or other metal elements in the same period as Co. Since different doped metals have different physical and chemical properties, such as atomic radius, electronegativity, nuclear outer electron layer, etc., these property differences lead to different degrees of modification of the electronic and geometric structures of cobalt tetroxide, thereby realizing the modulation of its electrochemical performance. The nano-chain structure is different from the conventional nano-spheres, cubic blocks, and nano-sheet structures. This special morphology will introduce many surface steps and unsaturated sites, which can enhance the electrochemical performance of the doped cobalt tetroxide catalytic material. This special structure also enriches the morphology structure types of metal-doped cobalt tetroxide nano-materials.
[0021] Furthermore, the doped metal M can be one metal or multiple metals, and its type and quantity can be adjusted according to the application fields and requirements of the cobalt tetroxide catalytic material, making the applicable range of this metal-doped cobalt tetroxide nano-chain catalytic material wide.
[0022] Furthermore, the longer the hydrothermal time and the higher the temperature, the larger the aspect ratio of the obtained nanowire structure. Therefore, the size of the subsequent nano-chain catalytic material structure can be adjusted.
[0023] Furthermore, the longer the annealing time and the higher the temperature, the smoother the surface structure of the obtained nano-chain catalytic material and the lower the oxygen defect concentration. Therefore, the surface properties and electrochemical performance of the metal-doped cobalt tetroxide nano-chain catalytic material can be adjusted. Description of the Drawings
[0024] Figure 1 XRD pattern of the product shown in Example 1;
[0025] Figure 2 SEM image and EDS spectrum of the morphology of the product shown in Example 1;
[0026] Among them, (a) figure is the SEM image of Example 1; (b) figure is the EDS spectrum of Example 1.
[0027] Figure 3 is the XRD pattern of the product shown in Example 2;
[0028] Figure 4 are the SEM image and EDS spectrum of the morphology of the product shown in Example 2;
[0029] Among them, (a) figure is the SEM image of Example 2; (b) figure is the EDS spectrum of Example 2.
[0030] Figure 5 is the TEM image of the product shown in Example 2;
[0031] Figure 6 is the XRD pattern of the product shown in Example 3;
[0032] Figure 7 are the SEM image and EDS spectrum of the morphology of the product shown in Example 3;
[0033] Among them, (a) figure is the SEM image of Example 3; (b) figure is the EDS spectrum of Example 3. Detailed implementation manners
[0034] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. The present invention discloses a preparation method of a metal-doped cobalt tetroxide nanorod chain catalytic material, and the preparation method includes the following steps:
[0035] Step 1: Add cobalt nitrate and metal salt into a mixed solvent of ethanol and water (volume ratio 1:1), stir until completely dissolved, and then add urea. Pour the mixed solution into a reaction kettle with a polytetrafluoroethylene lining. After the hydrothermal reaction is completed, obtain a metal-doped basic cobalt carbonate nanowire material through centrifugation, washing, and drying.
[0036] Step 2: Put the obtained metal-doped basic cobalt carbonate nanorod chain material into a crucible, calcine it in a high-temperature air atmosphere to completely decompose and oxidize it, and obtain a metal-doped cobalt tetroxide nanorod chain catalytic material after cooling to room temperature.
[0037] Specifically, the concentration of cobalt nitrate in the ethanol and water mixed solution is (200 - 400) mg: 30 mL; the concentration of metal salt in the ethanol and water mixed solution is (10 - 200 mg): 30 mL; the concentration of urea in the ethanol and water mixed solution is (500 - 1800 mg): 30 mL. During the preparation process, if the metal salt is not added according to the stoichiometric ratio, doping cannot be formed and impurity phases will appear. If urea is not added according to the stoichiometric ratio, basic carbonate cannot be formed;
[0038] Specifically, the hydrothermal temperature is 110 - 130 °C and the time is 120 - 240 min, enabling the growth of a nano-linear structure.
[0039] Specifically, the calcination temperature is 350 - 400 °C and the calcination time is 30 - 90 min; by controlling the calcination time and temperature, metal-doped cobalt tetroxide nano-chains are formed.
[0040] Specifically, the metal salts include one or more of metal salts such as copper acetate, zinc sulfate, copper acetate, zinc sulfate, ammonium metavanadate, iridium acetate, manganese acetate, nickel acetate, etc.
[0041] The metal-doped cobalt tetroxide nano-chain catalytic material prepared by the above method is chain-shaped, that is, there are protruding metal-doped cobalt tetroxide on the linear metal-doped cobalt tetroxide.
[0042] Example 1
[0043] 100 mg of copper acetate and 300 mg of cobalt nitrate were added to a mixed solution of 30 ml of ethanol and water (volume ratio 1:1). After complete dissolution, 1000 mg of urea was added, and after mixing evenly, it was placed in a hydrothermal autoclave. The temperature was raised to 120 °C at room temperature and maintained for 200 min. After the temperature was cooled to room temperature, it was transferred to a centrifuge tube and centrifugally washed 4 times with absolute ethanol, centrifuging at 10000 rmp for 10 minutes each time. The finally obtained catalyst was dried in a vacuum drying oven for 2 h. A copper-doped cobalt tetroxide nano-chain material was obtained. The obtained copper-doped cobalt tetroxide nano-chain material was placed in a crucible and calcined in an air atmosphere at 350 °C for 30 min to decompose and oxidize it. After cooling to room temperature, a copper-doped cobalt tetroxide nano-chain catalytic material was obtained.
[0044] Figure 1 This is the XRD pattern of the copper-doped cobalt tetroxide nano-chains obtained in Example 1 of the present invention. It can be seen that the XRD characteristic peaks of the substance prepared in Example 1 correspond one by one to the characteristic peaks of cubic Co3O4 (JCPDS No. 43 - 1003). All diffraction angles are shifted relative to the characteristic peaks of the standard cubic Co3O4, which is a typical characteristic of element doping.
[0045] Figure 2SEM and EDS spectra of the copper-doped cobalt tetroxide nanorods obtained in Example 1 of the present invention. Among them, (a) is the SEM image. It can be seen that the sample prepared in this example has a nanorod structure. (b) is the EDS spectrum of (a). It can be seen that the sample prepared in this example contains three elements: Co, Cu, and O. Table 1 shows the specific content of the elements detected by this EDS spectrum. It can be seen from the table that Cu is successfully introduced into Co3O4, and the atomic ratio of Cu to Co is about 1:3, which is basically consistent with the amount of the precursor added. Combining the XRD results analysis, it can be determined that the sample prepared in this example is copper-doped cobalt tetroxide nanorods, and the doped copper replaces the position of cobalt in the original lattice.
[0046] Table 1 shows the element content of the product shown in Example 1
[0047]
[0048]
[0049] Example 2
[0050] 20 mg of zinc sulfate and 200 mg of cobalt nitrate were added to a mixed solution of 30 ml of ethanol and water (volume ratio 1:1). After complete dissolution, 1200 mg of urea was added. After mixing evenly, it was placed in a hydrothermal reactor. The temperature was raised from room temperature to 120 °C and maintained for 200 min. After the temperature was cooled to room temperature, it was transferred to a centrifuge tube and centrifugally washed 4 times with absolute ethanol, centrifuging at 10000 rmp for 10 minutes each time. The finally obtained catalyst was dried in a vacuum drying oven for 4 h. A zinc-doped cobalt tetroxide nanorod material was obtained. The obtained zinc-doped cobalt tetroxide nanorod material was placed in a crucible and calcined in an air atmosphere at 400 °C for 60 min to completely decompose and oxidize it. After cooling to room temperature, a zinc-doped cobalt tetroxide nanorod catalytic material was obtained.
[0051] Figure 3 XRD pattern of the zinc-doped cobalt tetroxide nanorod catalytic material obtained in Example 2 of the present invention. It can be seen that for the substance prepared in Example 2, its XRD characteristic peaks correspond one by one to the characteristic peaks of cubic Co3O4 (JCPDS No. 43-1003). All diffraction angles are shifted relative to the characteristic peaks of the standard cubic Co3O4, which is a typical characteristic of element doping.
[0052] Figure 4SEM and EDS spectra of the cobalt spinel oxide nanorod catalyst doped with zinc obtained in Example 2 of the present invention. In Fig. (a), it is the SEM image, and it can be seen that the sample prepared in this example has a nanorod structure. In Fig. (b), it is the EDS spectrum of Fig. (a), and it can be seen that the sample prepared in this example contains three elements: Co, Zn, and O. Table 2 shows the specific content of the elements detected by the EDS spectrum. It can be seen from the table that Zn is successfully introduced into Co3O4, and the atomic ratio of Zn to Co is about 1:9, which is basically consistent with the addition amount of the precursor. Combining with the XRD results analysis, it can be determined that the sample prepared in this example is cobalt spinel oxide nanorods doped with zinc.
[0053] Figure 5 TEM image of the cobalt spinel oxide nanorod material doped with zinc obtained in Example 2 of the present invention further confirms its nanorod structure.
[0054] Table 2 shows the element content of the product shown in Example 2
[0055]
[0056] Example 3
[0057] 5 mg of copper acetate, 5 mg of zinc sulfate, 70 mg of ammonium metavanadate, 25 mg of iridium acetate and 400 mg of cobalt nitrate were added to a mixed solution of 30 ml of ethanol and water (volume ratio of 1:1). After complete dissolution, 1200 mg of urea was added, and after mixing evenly, it was put into a hydrothermal reactor. The temperature was raised to 120 °C at room temperature and maintained for 200 min. After the temperature was cooled to room temperature, it was transferred to a centrifuge tube and centrifuged and washed 4 times with absolute ethanol at a rotation speed of 10000 rmp for 10 minutes each time. The finally obtained catalyst was dried in a vacuum drying oven for 4 h. A cobalt spinel oxide nanorod catalyst doped with copper, zinc, vanadium and iridium was obtained. The obtained cobalt spinel oxide nanorod catalyst doped with copper, zinc, vanadium and iridium was put into a crucible and calcined in an air atmosphere at 400 °C for 90 min to completely decompose and oxidize it. After cooling to room temperature, a cobalt spinel oxide nanorod catalytic material doped with copper, zinc, vanadium and iridium was obtained.
[0058] Figure 6 XRD pattern of the cobalt spinel oxide nanorod catalyst doped with copper, zinc, vanadium and iridium obtained in Example 3 of the present invention. It can be seen that the XRD characteristic peaks of the substance prepared in Example 3 correspond one by one to the characteristic peaks of cubic Co3O4 (JCPDS No. 43-1003). All diffraction angles deviate from the characteristic peaks of the standard cubic Co3O4, which is a typical characteristic of element doping.
[0059] Figure 7SEM and EDS spectra of the copper, zinc, vanadium, iridium-doped cobalt tetroxide nano-chain catalyst obtained in Example 3 of the present invention. Among them, (a) is the SEM image. It can be seen that the sample prepared in this example has a nano-chain structure. (b) is the EDS spectrum of (a). It can be seen that the sample prepared in this example contains three elements: Co, Cu, Zn, V, Ir, and O. Table 3 shows the specific content of the elements detected by this EDS spectrum. It can be seen from the table that Cu, Zn, V, and Ir are successfully introduced into Co3O4, and the atomic ratio of Co, Cu, Zn, V, and Ir is about 80:1:1:15, which is basically consistent with the addition amount of the precursor. Combining with the XRD results analysis, it can be determined that the sample prepared in this example is copper, zinc, vanadium, iridium-doped cobalt tetroxide nano-chains.
[0060] Table 3 shows the element content of the product shown in Example 3
[0061]
[0062] Example 4
[0063] Add 20 mg of manganese acetate and 400 mg of cobalt nitrate to 30 ml of a mixed solution of ethanol and water (volume ratio 1:1). After complete dissolution, add 500 mg of urea, mix well and put it into a hydrothermal reactor. Start heating from room temperature to 130 °C and keep it for 240 min. After the temperature cools down to room temperature, transfer it to a centrifuge tube and centrifuge and wash it 4 times with absolute ethanol, centrifuge at a speed of 10000 rmp for 10 minutes each time. The finally obtained catalyst is dried in a vacuum drying oven for 4 h. A manganese-doped cobalt tetroxide nano-chain material is obtained. Put the obtained manganese-doped cobalt tetroxide nano-chain material into a crucible and calcine it in an air atmosphere at 350 °C for 30 min to completely decompose and oxidize it. After cooling to room temperature, a manganese-doped cobalt tetroxide nano-chain catalytic material is obtained.
[0064] Example 5
[0065] Add 10 mg of nickel acetate and 200 mg of cobalt nitrate to 30 ml of a mixed solution of ethanol and water (volume ratio 1:1). After complete dissolution, add 1200 mg of urea, mix well and put it into a hydrothermal reactor. Start heating from room temperature to 130 °C and keep it for 240 min. After the temperature cools down to room temperature, transfer it to a centrifuge tube and centrifuge and wash it 4 times with absolute ethanol, centrifuge at a speed of 10000 rmp for 10 minutes each time. The finally obtained catalyst is dried in a vacuum drying oven for 4 h. A nickel-doped cobalt tetroxide nano-chain material is obtained. Put the obtained nickel-doped cobalt tetroxide nano-chain material into a crucible and calcine it in an air atmosphere at 400 °C for 90 min to completely decompose and oxidize it. After cooling to room temperature, a nickel-doped cobalt tetroxide nano-chain catalytic material is obtained.
[0066] Example 6
[0067] 150 mg of manganese acetate and 250 mg of cobalt nitrate were added to a mixed solution of 30 ml of ethanol and water (volume ratio 1:1). After complete dissolution, 800 mg of urea was added. After mixing evenly, it was placed in a hydrothermal reactor. The temperature was raised from room temperature to 110 °C and maintained for 120 min. After the temperature cooled to room temperature, it was transferred to a centrifuge tube and centrifugally washed 4 times with absolute ethanol, centrifuging at 10,000 rmp for 10 minutes each time. The finally obtained catalyst was dried in a vacuum drying oven for 4 h. A manganese-doped cobalt tetroxide nanocable material was obtained. The obtained manganese-doped cobalt tetroxide nanocable material was placed in a crucible and calcined in an air atmosphere at 380 °C for 80 min to completely decompose and oxidize it. After cooling to room temperature, a manganese-doped cobalt tetroxide nanocable catalytic material was obtained.
[0068] Example 7
[0069] 80 mg of manganese acetate and 350 mg of cobalt nitrate were added to a mixed solution of 30 ml of ethanol and water (volume ratio 1:1). After complete dissolution, 1800 mg of urea was added. After mixing evenly, it was placed in a hydrothermal reactor. The temperature was raised from room temperature to 125 °C and maintained for 180 min. After the temperature cooled to room temperature, it was transferred to a centrifuge tube and centrifugally washed 4 times with absolute ethanol, centrifuging at 10,000 rmp for 10 minutes each time. The finally obtained catalyst was dried in a vacuum drying oven for 4 h. A manganese-doped cobalt tetroxide nanocable material was obtained. The obtained manganese-doped cobalt tetroxide nanocable material was placed in a crucible and calcined in an air atmosphere at 390 °C for 50 min to completely decompose and oxidize it. After cooling to room temperature, a manganese-doped cobalt tetroxide nanocable catalytic material was obtained.
[0070] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A preparation method of a metal-doped cobalt tetroxide nano-chain catalytic material, characterized in that, It includes the following steps: Step 1: Cobalt nitrate and metal salts are added to a mixed solvent of ethanol and water. After stirring until completely dissolved, urea is added to obtain a mixed solution. Among them, the mixed mass ratio of cobalt nitrate, metal salts and urea is (200 - 400):(10 - 200):(500 - 1800); after the mixed solution undergoes a hydrothermal reaction, the hydrothermal reaction product is centrifuged, washed and dried to obtain nanowire-like metal-doped basic cobalt carbonate. Step 2: The nanowire-like metal-doped basic cobalt carbonate is placed in a crucible and calcined in a high-temperature air atmosphere to obtain chain-like metal-doped cobalt tetroxide.
2. The preparation method of a metal-doped cobalt tetroxide nanochain catalytic material according to claim 1, characterized in that, In Step 1, the volume ratio of ethanol to water is 1:
1.
3. The preparation method of a metal-doped cobalt tetroxide nano-chain catalytic material according to claim 1, characterized in that, In Step 1, the ratio of cobalt nitrate to the mixed solvent is: (200 - 400) mg: 30 mL.
4. The preparation method of a metal-doped cobalt tetroxide nano-chain catalytic material according to claim 1, characterized in that, In Step 1, the metal salts added are one or a mixture of copper acetate, zinc sulfate, copper acetate, zinc sulfate, ammonium metavanadate, iridium acetate, manganese acetate or nickel acetate.
5. The preparation method of a metal-doped cobalt tetroxide nano-chain catalytic material according to claim 1, characterized in that, In Step 1, the hydrothermal reaction temperature is 110 - 130 °C, and the hydrothermal reaction time is 120 - 240 min.
6. The preparation method of a metal-doped cobalt tetroxide nano-chain catalytic material according to claim 1, wherein In Step 1, the centrifugation speed is 1000 rmp, and the centrifugation time is 10 min.
7. The preparation method of a metal-doped cobalt tetroxide nano-chain catalytic material according to claim 1, characterized in that, In Step 1, the drying time is 2 - 4 h.
8. The preparation method of a metal-doped cobalt tetroxide nano-chain catalytic material according to claim 1, characterized in that, In Step 2, the calcination temperature is 350 - 400 °C, and the calcination time is 30 - 90 min.
9. A metal-doped cobalt tetroxide nanochain catalytic material prepared by the preparation method according to any one of claims 1 - 7.