CoO / Co3O4 composite material, preparation method and application thereof
The solvothermal method for preparing CoO/Co3O4 composite materials solves the problems of complex preparation and high cost in existing technologies, and achieves high yield, low cost material preparation and excellent photocatalytic performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ANKANG UNIV
- Filing Date
- 2026-04-17
- Publication Date
- 2026-06-09
AI Technical Summary
Existing methods for preparing CoO/Co3O4 composite materials are complex, have uneven phase distribution, weak interfacial bonding, and high costs, which limit their application in the field of photocatalytic CO2 reduction.
CoO/Co3O4 composite materials were prepared by a solvothermal method. The cobalt salt was ultrasonically dissolved in a mixed solution of small molecule alcohol and distilled water, followed by a solvothermal reaction in a reactor. Combined with cleaning and vacuum drying, the ratio of the two phases and the microstructure were precisely controlled.
A high-yield, low-cost large-scale preparation of CoO/Co3O4 composite materials was achieved, featuring a closely contacting heterogeneous interface that enhances photocatalytic performance.
Smart Images
Figure CN122164411A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of nanomaterial preparation technology, specifically relating to a CoO / Co3O4 composite material, its preparation method, and its application. Background Technology
[0002] The rapid depletion of carbon-based energy sources, coupled with the continuous rise in atmospheric carbon dioxide (CO2) concentrations, has led to serious energy and environmental problems. Converting CO2 into high-value-added chemicals (such as CO, CH4) is crucial. 4、 Photocatalytic CO2 reduction (CCO2 reduction, CO2 reduction, etc.) is one of the ideal pathways to achieve sustainable energy development. Photocatalytic CO2 reduction is an ideal technology for achieving this conversion, and its core lies in developing highly active, highly selective, and low-cost catalysts. Cobalt-based oxides (such as Co3O4, NiCo2O4, CoOx@CN, etc.) show promising applications in CO2 hydrogenation reactions due to their unique electronic structure and variable valence states. Co3O4 has a spinel structure and mixed valence states, readily forming oxygen vacancies on its surface, which is beneficial for the adsorption and activation of CO2 molecules; while CoO has excellent electronic conductivity, which is beneficial for electron transport in the catalytic reaction. Constructing CoO / Co3O4 composite materials and utilizing the synergistic effect between the two phases is expected to simultaneously optimize the activation and hydrogenation processes of CO2, thereby improving catalytic performance. The preparation methods of CoO / Co3O4 composite materials and their catalytic applications have attracted widespread attention from researchers. For example, Rinkoo Bhabal et al. first synthesized a carbon composite material derived from a cobalt metal-organic framework (Co-MOF), and then obtained a defect-rich mixed-phase cobalt oxide (CoO / Co3O4) system through phosphobic boronizing treatment. This system not only significantly improved the intrinsic kinetics of hydrogen evolution and oxygen evolution reactions, but also exhibited long-term durability and performance stability under industrial-related conditions. Jingquan Liu et al. reported the synthesis of a heterostructured CoO / Co3O4 nanowire array (CoO / Co3O4NA / Ti) on a titanium mesh surface by calcining a Co3O4 precursor in a reducing atmosphere (hydrogen / argon). This heterostructure effectively improved the catalytic activity of the hydrogen evolution reaction (HER). In addition, Nasser AM Barakat et al. synthesized CoO / Co3O4 nanofibers using a water-gas assisted process and evaluated them as a photocatalyst for the production of hydrogen from a methanol / water mixture under sunlight irradiation. The synthesized nanofibers exhibited excellent photocatalytic activity, with a hydrogen production rate of 66.9 mmol / g. catHowever, existing methods for preparing CoO / Co3O4 composite materials, such as multi-step impregnation methods and complex precursor pyrolysis methods, typically suffer from problems such as complex process flows, uneven two-phase distribution, weak interfacial bonding, and high costs, which restrict their large-scale preparation and practical application. Furthermore, there are almost no reports on the application of CoO / Co3O4 composite materials in the field of photocatalytic CO2 conversion. Therefore, developing a simple and efficient method for preparing CoO / Co3O4 composite materials that can precisely control the two-phase ratio and microstructure is of great significance for promoting the development of photocatalytic CO2 reduction technology. Summary of the Invention
[0003] To address the problems of complex synthesis process, weak interfacial bonding, and high cost of CoO / Co3O4 composite materials, this invention provides a simple and efficient method for preparing CoO / Co3O4 composite materials that can precisely control the ratio and microstructure of the two phases, and its application in photocatalytic CO2 reduction reaction.
[0004] To achieve the above objectives, the present invention employs the following technical solution:
[0005] This invention provides a method for preparing a CoO / Co3O4 composite material, comprising the following steps:
[0006] Step 1: Dissolve the cobalt salt in a mixed solution of small molecule alcohol and distilled water by ultrasonication to obtain a purple transparent solution;
[0007] Step 2: Place the purple transparent solution obtained in Step 1 into a reaction vessel and carry out a solvothermal reaction to obtain the crude CoO / Co3O4 product;
[0008] Step 3: The obtained crude CoO / Co3O4 product is washed and vacuum dried to obtain the CoO / Co3O4 composite material.
[0009] Furthermore, in step 1, the cobalt salt is one or more of cobalt chloride, cobalt nitrate, cobalt acetate, and cobalt acetylacetonate, and the small molecule alcohol is one or more of methanol, ethanol, and isopropanol.
[0010] Furthermore, in step 1, the volume ratio of small molecule alcohol to distilled water is 4~30:1, and the concentration of cobalt salt is 1~100 mmol / L.
[0011] Furthermore, the ultrasound time in step 1 is 10-30 minutes.
[0012] Furthermore, in step 2, the temperature of the solvothermal reaction is 120~200℃, and the time is 6~48 h.
[0013] Furthermore, in step 2, the solution filling ratio in the reactor is 40~80 vol.%.
[0014] Furthermore, in step 3, the washing process involves centrifuging with ethanol and distilled water 3 to 10 times, with a centrifugation speed of 5000 to 10000 r / min.
[0015] Furthermore, in step 3, the vacuum drying process involves a vacuum degree of -30 kPa, a temperature of 60°C, and a time of 12~24 h.
[0016] The present invention also provides a CoO / Co3O4 composite material prepared by the above preparation method.
[0017] The present invention also provides an application of the CoO / Co3O4 composite material for photocatalytic CO2 reduction reaction, which has excellent catalytic performance.
[0018] Compared with the prior art, the present invention has the following advantages:
[0019] (1) The CoO / Co3O4 composite material synthesized in this invention has a high yield and is easy to prepare on a large scale;
[0020] (2) The synthesis process of this invention uses simple raw materials, mild conditions, and few process steps;
[0021] (3) The present invention has low synthesis cost. The synthesis process only requires inexpensive cobalt salt, small molecule alcohol and distilled water as raw materials, and does not require special processing equipment;
[0022] (4) The CoO / Co3O4 composite material prepared by the present invention has a closely contacted heterogeneous interface, which is conducive to improving the separation and migration of charge carriers, thereby effectively improving the catalytic performance. Attached Figure Description
[0023] Figure 1 X-ray powder diffraction (XRD) patterns of commercially available CoO (C-CoO), Co3O4 prepared by pyrolysis (T-Co3O4), and the CoO / Co3O4 composite material synthesized in Example 1.
[0024] Figure 2 The image shown is a scanning electron microscope (SEM) image of the CoO / Co3O4 composite material synthesized in Example 1.
[0025] Figure 3 The photocatalytic carbon dioxide reduction performance of the CoO / Co3O4 composite material synthesized in Example 1 under visible light irradiation was determined. Detailed Implementation
[0026] To further illustrate the technical solution of the present invention, the present invention will be further described below through embodiments.
[0027] Example 1
[0028] This embodiment describes a method for preparing a CoO / Co3O4 composite material, comprising the following steps:
[0029] Step 1: Take 0.3 g of cobalt acetate in a 150 mL beaker, add 70 mL of ethanol and 10 mL of distilled water (ethanol-distilled water volume ratio is 7, cobalt acetate concentration is 21 mmol / L), and sonicate for 20 min to completely dissolve the cobalt acetate in the mixture of ethanol and distilled water to obtain a purple transparent solution.
[0030] Step 2: The purple transparent solution obtained in Step 1 is transferred to a polytetrafluoroethylene substrate in a 100 mL reactor for solvothermal reaction. The solution filling ratio is 80 vo1.%, the solvothermal temperature is 180 ℃, and the time is 12 h to obtain the crude product CoO / Co3O4.
[0031] Step 3: The crude CoO / Co3O4 product obtained in Step 2 was washed 8 times by centrifugation with ethanol and distilled water (centrifuge speed 8000 r / min), and then vacuum dried at 60℃ (vacuum degree -30 kPa) for 12 h to obtain the CoO / Co3O4 composite material.
[0032] Figure 1 The images show X-ray powder diffraction (XRD) patterns of commercially available CoO (C-CoO), Co3O4 prepared by pyrolysis (T-Co3O4), and the CoO / Co3O4 composite material synthesized in Example 1 of this invention. It can be seen that CoO / Co3O4 simultaneously displays the characteristic diffraction peaks of CoO and Co3O4, indicating that the CoO / Co3O4 composite material was successfully prepared by this method.
[0033] Figure 2 The image shown is a scanning electron microscope (SEM) image of the CoO / Co3O4 composite material synthesized in Example 1, illustrating that the CoO / Co3O4 composite material prepared by this method exhibits an irregular cubic structure.
[0034] Figure 3 The photocatalytic carbon dioxide reduction performance of the CoO / Co3O4 composite material synthesized in Example 1 under visible light irradiation was investigated. By comparison, the CoO / Co3O4 composite material prepared in this invention exhibits superior photocatalytic carbon dioxide reduction performance.
[0035] Example 2
[0036] This embodiment describes a method for preparing a CoO / Co3O4 composite material, comprising the following steps:
[0037] Step 1: Take 0.01 g of cobalt acetylacetonate in a 150 mL beaker, add 32 mL of methanol and 8 mL of distilled water (methanol-distilled water volume ratio is 4, cobalt acetylacetonate concentration is 1 mmol / L), and sonicate for 30 min to completely dissolve cobalt acetylacetonate in the mixed solution of methanol and distilled water to obtain a purple transparent solution.
[0038] Step 2: The purple transparent solution obtained in Step 1 is transferred to a polytetrafluoroethylene substrate in a 100 mL reactor for solvothermal reaction. The solution filling ratio is 40 vo1.%, the solvothermal temperature is 160 ℃, and the time is 6 h to obtain the crude product CoO / Co3O4.
[0039] Step 3: The crude CoO / Co3O4 product obtained in Step 2 is washed 10 times by centrifugation with ethanol and distilled water (centrifuge speed 10000 r / min), and then vacuum dried at 60℃ (vacuum degree -30 kPa) for 24 h to obtain the CoO / Co3O4 composite material.
[0040] Example 3
[0041] This embodiment describes a method for preparing a CoO / Co3O4 composite material, comprising the following steps:
[0042] Step 1: Take 1.5 g of cobalt nitrate in a 150 mL beaker, add 58 mL of ethanol and 2 mL of distilled water (ethanol-distilled water volume ratio is 2:9, cobalt nitrate concentration is 86 mmol / L), sonicate for 10 min to completely dissolve cobalt nitrate in the mixture of ethanol and distilled water, and obtain a purple transparent solution.
[0043] Step 2: The purple transparent solution obtained in Step 1 is transferred to a polytetrafluoroethylene substrate in a 100 mL reactor for solvothermal reaction. The solution filling ratio is 60 vo1.%, the solvothermal temperature is 140 ℃, and the time is 24 h to obtain the crude product CoO / Co3O4.
[0044] Step 3: The crude CoO / Co3O4 product obtained in Step 2 was washed 6 times by centrifugation with ethanol and distilled water (centrifuge speed 5000 r / min), and then vacuum dried at 60℃ (vacuum degree -30 kPa) for 24 h to obtain the CoO / Co3O4 composite material.
[0045] Example 4
[0046] This embodiment describes a method for preparing a CoO / Co3O4 composite material, comprising the following steps:
[0047] Step 1: Take 0.46 g of cobalt chloride in a 150 mL beaker, add 65 mL of isopropanol and 5 mL of distilled water (the volume ratio of isopropanol to distilled water is 1:3, and the concentration of cobalt chloride is 50 mmol / L), and sonicate for 15 min to completely dissolve the cobalt chloride in the mixture of isopropanol and distilled water to obtain a purple transparent solution.
[0048] Step 2: The purple transparent solution obtained in Step 1 is transferred to a polytetrafluoroethylene substrate in a 100 mL reactor for solvothermal reaction. The solution filling ratio is 70 vo1.%, the solvothermal temperature is 120 ℃, and the time is 48 h to obtain the crude product CoO / Co3O4.
[0049] Step 3: The crude CoO / Co3O4 product obtained in Step 2 was washed three times by centrifugation with ethanol and distilled water (centrifuge speed 8000 r / min), and then vacuum dried at 60℃ (vacuum degree -30 kPa) for 12 h to obtain the CoO / Co3O4 composite material.
[0050] The foregoing has shown and described the main features and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.
[0051] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A method for preparing a CoO / Co3O4 composite material, characterized in that, Includes the following steps: Step 1: Dissolve the cobalt salt in a mixed solution of small molecule alcohol and distilled water by ultrasonication to obtain a purple transparent solution; Step 2: Place the purple transparent solution obtained in Step 1 into a reaction vessel and carry out a solvothermal reaction to obtain the crude CoO / Co3O4 product; Step 3: The obtained crude CoO / Co3O4 product is washed and vacuum dried to obtain the CoO / Co3O4 composite material.
2. The method for preparing a CoO / Co3O4 composite material according to claim 1, characterized in that, In step 1, the cobalt salt is one or more of cobalt chloride, cobalt nitrate, cobalt acetate, and cobalt acetylacetonate, and the small molecule alcohol is one or more of methanol, ethanol, and isopropanol.
3. The method for preparing a CoO / Co3O4 composite material according to claim 1, characterized in that, In step 1, the volume ratio of small molecule alcohol to distilled water is 4~30:1, and the concentration of cobalt salt is 1~100 mmol / L.
4. The method for preparing a CoO / Co3O4 composite material according to claim 1, characterized in that, The ultrasound time in step 1 is 10-30 minutes.
5. The method for preparing a CoO / Co3O4 composite material according to claim 1, characterized in that, In step 2, the temperature of the solvothermal reaction is 120~200℃, and the time is 6~48 h.
6. The method for preparing a CoO / Co3O4 composite material according to claim 1, characterized in that, In step 2, the solution filling ratio in the reactor is 40~80 vol.
7. The method for preparing a CoO / Co3O4 composite material according to claim 1, characterized in that, In step 3, the washing process involves centrifuging with ethanol and distilled water 3 to 10 times, with a centrifugation speed of 5000 to 10000 r / min.
8. The method for preparing a CoO / Co3O4 composite material according to claim 1, characterized in that, In step 3, the vacuum drying process involves a vacuum level of -30 kPa, a temperature of 60°C, and a time of 12-24 hours.
9. The CoO / Co3O4 composite material prepared by the preparation method of any one of claims 1 to 8.
10. The application of the CoO / Co3O4 composite material according to claim 9, characterized in that, Used for photocatalytic CO2 reduction reaction.