A flower-like structure of copper-cobalt oxide Cu 0.92 Co 2.08 Preparation methods and applications of O4
By controlling the amount of cationic surfactant in the preparation method, a flower-like copper-cobalt oxide Cu0.92Co2.08O4 was successfully prepared, filling the gap in the application of copper-cobalt oxide in the hydrolysis of NaBH4 to produce hydrogen and realizing the high efficiency of non-precious metal catalyst.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUILIN UNIV OF ELECTRONIC TECH
- Filing Date
- 2024-11-20
- Publication Date
- 2026-05-05
AI Technical Summary
In the existing technology, copper-cobalt oxide Cu0.92Co2.08O4 has not been used to catalyze the hydrolysis of metal hydride NaBH4 to produce hydrogen. Moreover, precious metal catalysts are expensive and scarce, so it is necessary to find non-precious metal catalysts that are cheaper and more abundant.
Cobalt and copper sources were dissolved in water, and a cationic surfactant was added. After stirring and dissolving, a reducing agent was added for reduction. After filtration and washing with water, the mixture was calcined at 300~500℃ to prepare flower-shaped copper-cobalt oxide Cu0.92Co2.08O4. The amount of cationic surfactant was controlled at 0.59~0.75 times the molar amount of cobalt source.
When the prepared copper-cobalt oxide Cu0.92Co2.08O4 was used as a catalyst for the hydrolysis of NaBH4, it significantly improved the hydrogen evolution rate, showing a significant improvement compared to catalysts without or with amounts outside the specified range.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of catalyst technology, specifically to a flower-like structure of copper-cobalt oxide Cu. 0.92 Co 2.08 Preparation methods and applications of O4. Background Technology
[0002] With the depletion of fossil fuels and the increase in carbon dioxide emissions, the greenhouse effect is becoming increasingly severe. To mitigate its impact on the global environment, hydrogen energy, due to its high calorific value and zero carbon dioxide emissions, is considered an ideal energy source for the future. Therefore, developing efficient and safe hydrogen storage materials has become particularly important.
[0003] Sodium borohydride (NaBH4) has become a research focus due to its high hydrogen storage capacity (10.57 wt%), stability in alkaline solutions, and the non-toxicity and recyclability of its hydrolysis products. However, the self-hydrolysis reaction of NaBH4 at room temperature is very slow. The use of catalysts can lower the kinetic energy barrier of NaBH4 hydrolysis, thereby increasing the hydrogen production rate and reaction efficiency, making its application more controllable. Currently, although noble metal catalysts (such as Pd and Ru) exhibit good catalytic performance, their scarcity and high cost limit their industrial application. Therefore, finding lower-cost and more abundant non-noble metal catalysts has become an important direction for replacing noble metal catalysts.
[0004] Among transition metal compounds, cobalt-based phosphides, borides, and oxides exhibit excellent catalytic performance for the hydrolysis of NaBH4. In particular, composite bimetallic catalysts, such as bimetallic oxide catalysts prepared through in-situ reduction and high-temperature calcination, demonstrate high hydrogen evolution rates due to their electron transfer and bimetallic synergistic effects. Therefore, in-depth research into the application of non-noble metal bimetallic catalysts in the hydrolysis of NaBH4 for hydrogen production will contribute to promoting its industrial application.
[0005] Mingzhen Hu et al. provided a general template-free method to successfully synthesize Co3O4, CoO, and Cu. 0.92 Co 2.08 04, MnCo2O 4.5 Six mesoporous transition oxides, including ZnCo2O4 and CuO, are used, among which Cu... 0.92 Co 2.08 04, MnCo2O 4.5Both ZnCo2O4 and Co3O4 exhibit a two-dimensional plate-like structure, and it has been pointed out that Co3O4 and others can catalyze the decomposition of hydrogen peroxide to produce oxygen (Hu et al., Template-free Synthesis of Mesoporous and Crystalline Transition Metal Oxide Nanoplates with Abundant Surface Defects, Matter 2, 1-16, May 6, 2020.). However, copper-cobalt oxide Cu has not been found in existing technologies. 0.92 Co 2.08 Reports on the application of O4 as a catalyst in the hydrolysis of metal hydrides (such as NaBH4) to produce hydrogen. Summary of the Invention
[0006] The technical problem to be solved by this invention is to provide a novel flower-like structure of copper-cobalt oxide (Cu). 0.92 Co 2.08 Preparation method and application of O4, copper cobalt oxide Cu prepared by the method described in this invention. 0.92 Co 2.08 O4 exhibits good catalytic performance as a catalyst for the hydrolysis of NaBH4.
[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:
[0008] A flower-like structure of copper-cobalt oxide Cu 0.92 Co 2.08 The preparation method of O4 specifically includes: dissolving a cobalt source and a copper source in water, adding a cationic surfactant, stirring to dissolve, and obtaining a mixture; adding a reducing agent to the obtained mixture to carry out a reduction reaction; after the reaction is completed, filtering, collecting the precipitate, washing with water until neutral, and obtaining the precursor; calcining the obtained precursor to obtain the flower-like structured copper cobalt oxide Cu. 0.92 Co 2.08 O4; among which,
[0009] The molar ratio of the cobalt source to the copper source is 3:1;
[0010] The cationic surfactant is selected from one or more of CTAB (hexadecyltrimethylammonium bromide), DODMAC (docosahexadecyldimethylammonium chloride), HTAC (hexadecyltrimethylammonium chloride), DDAB (docosahexadecyldimethylbenzotrimethylammonium chloride), benzalkonium chloride, and stearalkonium chloride.
[0011] The amount of the cationic surfactant used is 0.59 to 0.75 times the molar amount of the cobalt source.
[0012] In the above technical solution, the cobalt source can be one or a combination of two or more selected from cobalt chloride, cobalt chloride hydrate (such as cobalt chloride hexahydrate), cobalt nitrate, and cobalt nitrate hydrate (such as cobalt nitrate hexahydrate); preferably cobalt chloride or cobalt chloride hexahydrate.
[0013] In the above technical solution, the copper source can be one or a combination of two or more selected from copper chloride, copper chloride hydrates (such as copper chloride monohydrate, copper chloride dihydrate, copper chloride trihydrate or copper chloride tetrahydrate, etc.), copper nitrate, and copper nitrate hydrates (such as copper nitrate trihydrate, etc.); preferably copper chloride.
[0014] In the above technical solution, the selection and dosage of the reducing agent can be conventional choices in the prior art. Specifically, the reducing agent can be one or a combination of two or more selected from sodium borohydride, lithium aluminum hydride and sodium bisulfite. The dosage of the reducing agent is usually in excess relative to the cobalt source. Preferably, the molar ratio of cobalt source to reducing agent is 1:1.5~3.
[0015] To avoid an overly vigorous reaction, the reduction reaction is preferably carried out under ice-water bath conditions; more preferably, the reducing agent is prepared as an aqueous solution and then added dropwise to the mixture to carry out the reduction reaction.
[0016] In the above technical solution, calcination is preferably carried out at 300~500℃, and the calcination time is preferably 2~4 hours. Calcination is usually carried out in a muffle furnace.
[0017] The applicant discovered in experiments that the amount of cationic surfactant has a significant impact on the catalytic activity of the obtained copper-cobalt oxide. When the amount of cationic surfactant is outside the aforementioned limit, the hydrogen production rate of the obtained copper-cobalt oxide during the catalytic hydrolysis of NaBH4 is significantly reduced. Preferably, the amount of cationic surfactant is 0.64 to 0.72 times the molar amount of cobalt source. In a more preferred embodiment, the amount of cationic surfactant is 0.72 times the molar amount of cobalt source.
[0018] Preferably, the cationic surfactant is CTAB.
[0019] In this application, the water generally refers to deionized water, and the amount of water used is preferably sufficient to dissolve all the raw materials participating in the reaction. Preferably, based on 1 mmol of cobalt source, the amount of water used for all raw materials is preferably controlled between 4 and 10 mL.
[0020] This invention further includes copper-cobalt oxide (Cu) prepared by the above method. 0.92 Co 2.08The application of O4 in the preparation of hydrogen evolution catalysts, specifically in the preparation of metal hydride water evolution catalysts, and more specifically in the preparation of NaBH4 water evolution catalysts.
[0021] Compared with existing technologies, this invention provides a method for preparing copper cobalt oxide Cu. 0.92 Co 2.08 A new method for preparing O4, electron micrographs show that the copper-cobalt oxide Cu obtained by this method... 0.92 Co 2.08 O4 exhibits a flower-like structure. The applicant's experimental results show that the copper-cobalt oxide Cu obtained by the method described in this invention... 0.92 Co 2.08 O4, as a catalyst, exhibits a good hydrogen evolution rate when used for hydrogen evolution from NaBH4 water, compared to copper-cobalt oxides (Cu) obtained without the addition of cationic surfactants or in amounts not limited to those specified in this application. 0.92 Co 2.08 The hydrogen evolution rate of O4 was significantly improved. Attached Figure Description
[0022] Figure 1 The copper-cobalt oxide Cu prepared in Examples 1, 1-1, 1-2 and 1-6 of this invention 0.92 Co 2.08 X-ray diffraction pattern of O4.
[0023] Figure 2 The copper-cobalt oxide Cu prepared in Example 1 of this invention 0.92 Co 2.08 Electron micrograph of O4.
[0024] Figure 3 This is a schematic diagram of the water displacement test apparatus used in the catalytic NaBH4 hydrolysis hydrogen production experiment in Example 1 of the present invention; the numbers in the figure are: 1 round bottom flask, 2 water bath, 3 gas washing bottle, 4 square water tank, 5 electronic balance, 6 computer.
[0025] Figure 4 The copper-cobalt oxide Cu prepared in Example 1 and Comparative Examples 1-1 to 1-6 of this invention 0.92 Co 2.08 Hydrogen production volume-time curve of O4-catalyzed NaBH4 hydrolysis.
[0026] Figure 5 The copper-cobalt oxide Cu prepared in Examples 2-6 of this invention 0.92 Co 2.08 Hydrogen production volume-time curve of O4-catalyzed NaBH4 hydrolysis. Detailed Implementation
[0027] To better explain the technical solution of the present invention, the present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited thereto.
[0028] Example 1
[0029] 528 mg (2.2 mmol) of cobalt dichloride hexahydrate and 100 mg (0.74 mmol) of anhydrous copper chloride were added to 10 mL of deionized water and stirred for 30 min. Then, 546 mg (1.50 mmol) of CTAB (cobalt source to CTAB molar ratio of 1:0.68) was added, and stirring was continued for 2 h. The resulting mixture was placed in an ice-water bath, and 6 mmol of sodium borohydride aqueous solution (concentration of 0.6 mol / L) was added dropwise. The mixture was stirred in an ice-water bath for 2 h, filtered, and the precipitate (black) was collected. The precipitate was washed with deionized water until neutral and dried at 70 °C to obtain the precursor. The precursor was placed in a muffle furnace and calcined at 400 °C for 2 h. After cooling, the copper-cobalt oxide Cu was obtained. 0.92 Co 2.08 O4.
[0030] The product obtained in this embodiment is a black powder. X-ray diffraction and electron microscopy analyses were performed on the product obtained in this embodiment; the XRD pattern and electron micrograph are shown below. Figure 1 and Figure 2 As shown. By Figure 1 It can be seen that the product obtained in this embodiment is Cu. 0.92 Co 2.08 O4, by Figure 2 As can be seen, the product obtained in this embodiment exhibits a regular hexagonal flower-like structure.
[0031] The catalytic NaBH4 hydrolysis process for hydrogen production of the product obtained in this embodiment was tested using the water displacement method. A schematic diagram of the water displacement method testing apparatus is shown below. Figure 3 As shown, the specific test method is as follows:
[0032] Prepare a 50 mL mixed solution (containing 0.6 wt% NaBH4 + 0.4 wt% NaOH) in a round-bottom flask and immerse it in a water bath at 30°C. Then, add 10 mg of the powdered catalyst prepared in this example to the mixed solution and stir continuously. The catalytic reaction begins, and hydrogen is continuously produced and enters a gas washing bottle. The discharged water is introduced into a square water tank placed on an electronic balance. The mass of the discharged water is recorded in real time by an online testing system connected to a computer and converted into the volume of water discharged (i.e., the volume of hydrogen produced). The hydrogen production rate is calculated using the following formula:
[0033] Hydrogen production rate = Displacement volume (mL) / [Catalyst mass (g) × Catalytic time (t)]
[0034] Experimental results are as follows Figure 4 As shown. By Figure 4 It can be seen that the hydrogen production rate of catalytic NaBH4 obtained in this example is 3719.39 mL. min -1 g -1 .
[0035] Comparative Example 1-1
[0036] 176 mg (0.74 mmol) of cobalt dichloride hexahydrate and 100 mg (0.74 mmol) of anhydrous copper chloride were added to 10 mL of deionized water and stirred for 30 min. Then, 182 mg (0.5 mmol) of CTAB (cobalt source to CTAB molar ratio of 1:0.68) was added, and stirring was continued for 2 h. The resulting mixture was placed in an ice-water bath, and 6 mmol of sodium borohydride aqueous solution (concentration of 0.6 mol / L) was added dropwise. The mixture was stirred in an ice-water bath for 2 h, filtered, and the precipitate (black) was collected. The precipitate was washed with deionized water until neutral and dried at 70 °C to obtain the precursor. The precursor was placed in a muffle furnace and calcined at 300 °C for 2 h. After cooling, copper cobalt oxide Cu, which appeared as a black powder, was obtained. 0.92 Co 2.08 O4, its XRD pattern is as follows Figure 1 As shown.
[0037] The copper-cobalt oxide Cu obtained in this example was tested using the same testing apparatus and method as in Example 1. 0.92 Co 2.08 The hydrogen evolution rate of NaBH4 water catalysis by O4 was 1525.06 mL. min -1 g -1 .
[0038] Comparative Examples 1-2
[0039] 881 mg (3.70 mmol) of cobalt dichloride hexahydrate and 100 mg (0.74 mmol) of anhydrous copper chloride were added to 10 mL of deionized water and stirred for 30 min. Then, 364 mg (1.0 mmol) of CTAB (cobalt source to CTAB molar ratio of 1:0.27) was added, and stirring was continued for 2 h. The resulting mixture was placed in an ice-water bath, and 6 mmol of sodium borohydride aqueous solution (concentration of 0.6 mol / L) was added dropwise. The mixture was stirred in an ice-water bath for 2 h, filtered, and the precipitate (black) was collected. The precipitate was washed with deionized water until neutral and dried at 70 °C to obtain the precursor. The precursor was placed in a muffle furnace and calcined at 300 °C for 2 h. After cooling, copper cobalt oxide Cu, which appeared as a black powder, was obtained. 0.92 Co 2.08 O4, its XRD pattern is as follows Figure 1 As shown.
[0040] The copper-cobalt oxide Cu obtained in this example was tested using the same testing apparatus and method as in Example 1. 0.92 Co 2.08 The hydrogen evolution rate of O4-catalyzed NaBH4 water desorption was measured to be 2824.04 mL / min. min -1 g -1 .
[0041] Comparative Examples 1-3
[0042] 881 mg (3.70 mmol) of cobalt dichloride hexahydrate and 100 mg (0.74 mmol) of anhydrous copper chloride were added to 10 mL of deionized water and stirred for 30 min. Then, 728 mg (2.0 mmol) of CTAB (cobalt source to CTAB molar ratio of 1:0.54) was added, and stirring was continued for 2 h. The resulting mixture was placed in an ice-water bath, and 6 mmol of sodium borohydride aqueous solution (concentration of 0.6 mol / L) was added dropwise. The mixture was stirred in an ice-water bath for 2 h, filtered, and the precipitate (black) was collected. The precipitate was washed with deionized water until neutral and dried at 70 °C to obtain the precursor. The precursor was placed in a muffle furnace and calcined at 300 °C for 2 h. After cooling, copper cobalt oxide Cu, which appeared as a black powder, was obtained. 0.92 Co 2.08 O4.
[0043] The copper-cobalt oxide Cu obtained in this example was tested using the same testing apparatus and method as in Example 1. 0.92 Co 2.08 The hydrogen evolution rate of O4-catalyzed NaBH4 water desorption was measured to be 1806.16 mL. min -1 g -1 .
[0044] Comparative Examples 1-4
[0045] Example 1 was repeated, except that the amount of CTAB added was changed to 437 mg (1.2 mmol) (the molar ratio of cobalt source to CTAB was 1:0.55).
[0046] Finally, a black powdery copper-cobalt oxide (Cu) was obtained. 0.92 Co 2.08 O4.
[0047] The copper-cobalt oxide Cu obtained in this example was tested using the same testing apparatus and method as in Example 1. 0.92 Co 2.08The hydrogen evolution rate of O4-catalyzed NaBH4 water stripping was measured to be 2031.82 mL. min -1 g -1 .
[0048] Comparative Examples 1-5
[0049] Example 1 was repeated, except that the amount of CTAB added was changed to 620 mg (1.7 mmol) (the molar ratio of cobalt source to CTAB was 1:0.77).
[0050] Finally, a black powdery copper-cobalt oxide (Cu) was obtained. 0.92 Co 2.08 O4.
[0051] The copper-cobalt oxide Cu obtained in this example was tested using the same testing apparatus and method as in Example 1. 0.92 Co 2.08 The hydrogen evolution rate of O4-catalyzed NaBH4 water desorption was measured to be 2554.08 mL. min -1 g -1 .
[0052] Comparative Examples 1-6
[0053] Repeat Example 1, except that CTAB is not added.
[0054] Finally, a black powdery copper-cobalt oxide (Cu) was obtained. 0.92 Co 2.08 O4, its XRD pattern is as follows Figure 1 As shown.
[0055] The copper-cobalt oxide Cu obtained in this example was tested using the same testing apparatus and method as in Example 1. 0.92 Co 2.08 The hydrogen evolution rate of O4-catalyzed NaBH4 water desorption was measured to be 1861.85 mL. min -1 g -1 .
[0056] Example 2
[0057] Example 1 was repeated, except that the amount of CTAB added was changed to 474 mg (1.3 mmol) (the molar ratio of cobalt source to CTAB was 1:0.59).
[0058] Finally, a black powdery copper-cobalt oxide (Cu) was obtained. 0.92 Co 2.08O4.
[0059] The copper-cobalt oxide Cu obtained in this example was tested using the same testing apparatus and method as in Example 1. 0.92 Co 2.08 The hydrogen evolution rate of O4-catalyzed NaBH4 water desorption was measured to be 3305.58 mL. min -1 g -1 .
[0060] Example 3
[0061] Example 1 was repeated, except that the amount of CTAB added was changed to 510 mg (1.4 mmol) (the molar ratio of cobalt source to CTAB was 1:0.64).
[0062] Finally, a black powdery copper-cobalt oxide (Cu) was obtained. 0.92 Co 2.08 O4.
[0063] The copper-cobalt oxide Cu obtained in this example was tested using the same testing apparatus and method as in Example 1. 0.92 Co 2.08 The hydrogen evolution rate of O4-catalyzed NaBH4 water desorption was measured, and the results showed that the hydrogen evolution rate was 3558.0 mL. min -1 g -1 .
[0064] Example 4
[0065] Example 1 was repeated, except that the amount of CTAB added was changed to 582 mg (1.58 mmol) (the molar ratio of cobalt source to CTAB was 1:0.72).
[0066] Finally, a black powdery copper-cobalt oxide (Cu) was obtained. 0.92 Co 2.08 O4.
[0067] The copper-cobalt oxide Cu obtained in this example was tested using the same testing apparatus and method as in Example 1. 0.92 Co 2.08 The hydrogen evolution rate of O4-catalyzed NaBH4 water desorption was measured to be 5078.44 mL. min -1 g -1 .
[0068] Example 5
[0069] Repeat Example 1, except that the amount of CTAB added was changed to 601 mg (1.65 mmol) (the molar ratio of cobalt source to CTAB was 1:0.75).
[0070] Finally, a black powdery copper-cobalt oxide (Cu) was obtained. 0.92 Co 2.08 O4.
[0071] The copper-cobalt oxide Cu obtained in this example was tested using the same testing apparatus and method as in Example 1. 0.92 Co 2.08 The hydrogen evolution rate of O4-catalyzed NaBH4 water desorption was measured to be 3857.55 mL. min -1 g -1 .
[0072] Example 6
[0073] Example 1 was repeated, except that cobalt nitrate was used instead of cobalt dichloride hexahydrate, and copper nitrate trihydrate was used instead of anhydrous copper chloride.
[0074] Finally, a black powdery copper-cobalt oxide (Cu) was obtained. 0.92 Co 2.08 O4.
[0075] The copper-cobalt oxide Cu obtained in this example was tested using the same testing apparatus and method as in Example 1. 0.92 Co 2.08 The hydrogen evolution rate of O4-catalyzed NaBH4 water desorption was measured to be 3506.81 mL. min -1 g -1 .
Claims
1. A flower-shaped copper-cobalt oxide Cu for hydrogen evolution catalysis 0.92 Co 2.08 The method for preparing O4 is characterized by, Cobalt and copper sources were dissolved in water, and a cationic surfactant was added and stirred to obtain a mixture. A reducing agent was added to the mixture to carry out a reduction reaction. After the reaction was completed, the mixture was filtered, the precipitate was collected, and washed with water until neutral to obtain the precursor. The precursor was then calcined to obtain the flower-like copper-cobalt oxide Cu. 0.92 Co 2.08 O4; among which, The molar ratio of the cobalt source to the copper source is 3:1; The cationic surfactant is CTAB; The amount of the cationic surfactant used is 0.59 to 0.75 times the molar amount of the cobalt source.
2. The preparation method according to claim 1, characterized in that, The cobalt source is selected from one or more of cobalt chloride, cobalt chloride hydrate, cobalt nitrate, and cobalt nitrate hydrate.
3. The preparation method according to claim 1, characterized in that, The copper source is selected from one or more of copper chloride, copper chloride hydrate, copper nitrate, and copper nitrate hydrate.
4. The preparation method according to claim 1, characterized in that, The reducing agent is selected from one or a combination of two or more of sodium borohydride, lithium aluminum hydride, and sodium bisulfite.
5. The preparation method according to any one of claims 1 to 4, characterized in that, The reduction reaction was carried out under ice-water bath conditions.
6. The preparation method according to any one of claims 1 to 4, characterized in that, Calcination is carried out at 300~500℃.
7. The preparation method according to any one of claims 1 to 4, characterized in that, The amount of the cationic surfactant used is 0.64 to 0.72 times the molar amount of the cobalt source.
8. The copper-cobalt oxide Cu prepared by the method according to any one of claims 1 to 7 0.92 Co 2.08 Application of O4 in the preparation of hydrogen evolution catalysts.
9. The application according to claim 8, characterized in that, is Application in the preparation of hydrogen desorption catalysts from metal hydrides.