Preparation and application of co3o4@co3o4 / fe3o4 yolk-shell structure nanoreactor
By preparing a Co3O4@Co3O4/Fe3O4 yolk@eggshell structured nanoreactor, the problems of high difficulty in loading nanoparticles and low material utilization efficiency in nanoreactors were solved, achieving high catalytic performance and stable catalytic cycle.
Patent Information
- Application Number
- CN202311251683.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-26
- Publication Date
- 2025-11-21
- Estimated Expiration
- 2043-09-26
AI Technical Summary
It is difficult to load reactive nanoparticles into the carrier material in existing nanoreactors, and it is difficult to control their uniform distribution. The carrier material cannot provide reaction sites or additional functions, resulting in low material utilization efficiency and poor catalyst cycle stability.
A template-free assisted liquid-phase hydrolysis etching combined with adsorption impregnation method was used to prepare a Co3O4@Co3O4/Fe3O4 yolk@eggshell structured nanoreactor. By controlling the reaction conditions, the yolk@eggshell structure was formed, and the simultaneous synthesis of Co3O4 and Fe3O4 was achieved by electrostatic adsorption, thereby improving the active surface area and confined catalysis.
It improves catalytic activity, enhances confined catalytic efficiency, reduces reactant diffusion coefficient, and increases the contact probability between reactants and active sites, thus achieving high-efficiency catalytic performance and stable catalytic cycle.
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Abstract
Description
TECHNICAL FIELD
[0001] The application provides a template-free liquid-phase hydrolysis etching method combined with adsorption and impregnation, and a Co3O4@Co3O4 / Fe3O4 yolk-shell structure nanoreactor for confined catalytic oxidation is prepared, and belongs to the technical field of inorganic non-metallic materials. BACKGROUND
[0002] With the development of high-tech and the acceleration of industrialization, the problems of fossil energy crisis, global climate warming and environmental pollution have become new challenges for the progress of human society. At present, promoting water decomposition to produce hydrogen and oxygen, oil cracking, carbon dioxide reduction and fixation, and catalytic oxidation degradation of organic pollutants are key technologies for developing green clean energy, reasonably reusing greenhouse gases and inhibiting environmental pollution. The above processes are usually difficult to proceed spontaneously and rely on the intervention of heterogeneous catalysts to reduce the reaction barrier. Therefore, how to improve the efficiency of heterogeneous catalytic reaction has become a key technical problem in the field of energy and environmental catalysis.
[0003] Since the concept of "confined catalysis" and "nanoreactor" was proposed, it has been proved to be effective in improving the efficiency of heterogeneous catalytic reaction. Confined catalysis refers to a series of catalytic reactions occurring in a closed nanospace. The limited nanoreaction space can provide a special microenvironment, promote the enrichment of reactant molecules, cause the local increase of reactant concentration, and thus change the chemical reaction equilibrium and reduce the catalytic reaction energy barrier. Moreover, the confined space can prevent the catalytic reaction sites from excessive contact with the external complex environment, thereby reducing the probability of poisoning and deactivation and improving the stability of the catalyst. Nanoreactor refers to a nanocatalyst with a unique structure and can provide a confined nanospace. At present, molecular sieves, mesoporous silica, layered silicates, carbon nanotubes, halloysite nanotubes and other materials with hollow space are usually used as carriers, and nanocatalytic materials are loaded into the hollow cavity to form a nanoreactor. However, such nanoreactors still have significant shortcomings, for example, it is difficult to load reactive nanoparticles into the tube or interlayer of the carrier material, and it is difficult to control the uniform distribution of the nanoparticles in the tube or interlayer; the carrier material cannot provide reaction sites or additional functions for the nanoreactor, and cannot maximize the use of resources.
[0004] In summary, the use of nanoreactor to enhance the confined catalysis, improve the hydrogen production, petroleum cracking, carbon dioxide reduction / fixed and catalytic oxidation of organic pollutants efficiency is the future development trend of energy catalysis and environmental catalysis field research. Rational selection of catalytic materials, development of simple process method to build nanoreactor, improve the material utilization efficiency, enhance the recycling stability and recyclability of the current research need to solve the key technical problems. Based on the above discussion, the advantages of Co3O4 unique spinel structure, easy to adjust the micro morphology and stable physical and chemical properties, combined with the excellent magnetic performance characteristics of Fe3O4, a simple and easy to operate process to build a kind of easy to recycle magnetic Co3O4@Co3O4 / Fe3O4 nanometer yolk@egg shell structure nanoreactor. By improving the active surface area, introducing bimetallic redox cycle, and the way of multi-strategy combination of confined catalysis to enhance the catalytic efficiency of nanoreactor.
[0005] The implementation of the present application has important value and significance for the research and application of confined catalysis in water decomposition hydrogen production, petroleum cracking, carbon dioxide reduction / fixed and catalytic oxidation of organic pollutants, and provides research experience for promoting the comprehensive cross and organic integration of inorganic non-metallic materials and multi-disciplinary. SUMMARY
[0006] The present application uses a template-free liquid hydrolysis etching combined with adsorption and impregnation method to prepare Co3O4@Co3O4 / Fe3O4 yolk@egg shell structure nanoreactor for water decomposition hydrogen production, petroleum cracking, carbon dioxide reduction / fixed and catalytic oxidation of organic pollutants and other confined catalysis fields.
[0007] The present application provides a preparation method of Co3O4@Co3O4 / Fe3O4 yolk@egg shell structure nanoreactor for confined catalysis field, which basic idea is to use the special property of precursor material easy to hydrolysis, and to promote the uniform hydrolysis of precursor material to form yolk@egg shell structure precursor by adjusting the reaction conditions. On this basis, the electrostatic adsorption is used to promote the adsorption of iron source on the outer surface of yolk@egg shell structure, and the synchronous synthesis of Co3O4 and Fe3O4 is realized. Thus, the Co3O4@Co3O4 / Fe3O4 yolk@egg shell structure nanoreactor is obtained.
[0008] The preparation method of Co3O4@Co3O4 / Fe3O4 yolk@egg shell structure nanoreactor for confined catalysis field provided by the present application has the following main technical solutions:
[0009] 1) A certain amount of cobalt salt is dissolved in a certain volume of organic solvent, and the solvothermal reaction is carried out at 120-200℃ for 6-12 hours in a high-pressure reaction kettle. After cooling to room temperature, the precipitate is washed with anhydrous ethanol, and dried at 60-80℃ for standby use;
[0010] 2) Put a certain volume of deionized water in a reaction vessel, heat to 80~95℃ in a water bath, disperse a certain mass of the product obtained in step 1) in deionized water, hydrolyze and etch for 1.5~3 hours, then adsorb and impregnate with an iron source for 0.5~1.5 hours, after cooling to room temperature, wash the precipitate and dry at 60~80℃, then calcine at 300~500℃ in an air atmosphere for 1~5 hours, to obtain a Co3O4@Co3O4 / Fe3O4 yolk@eggshell structure nanoreactor.
[0011] In the above technical solution of the present application, the cobalt salt used in step 1) is one or a combination of several of cobalt chloride, cobalt acetate, cobalt sulfate, cobalt naphthenate, cobalt nitrate, cobalt fluoride, cobalt oxalate, and cobalt iso-octoate, and the organic solvent is a combination of two of ethanol, ethylene glycol, n-propanol, isopropanol, N,N dimethylformamide, acetone, glycerol, pentylene glycol, butanol, t-butanol, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethylene glycol monoethyl ether, formic acid, acetonitrile, N,N dimethylformamide amine, tributyl methyl ether, and isopropyl acetate, and their volume ratio is 2~4, and the selection of the organic solvent needs to satisfy the solubility of the cobalt salt.
[0012] In the above technical solution of the present application, the reaction device used in step 2) needs to satisfy the conditions of sealing, water bath, and stirring, and the ratio of the volume of deionized water to the mass of the product obtained in step 1) in step 2) is (500~1000) mL : 1 g, and the iron source used is one or a combination of several of ferrous sulfate, ferric sulfate, ferrous nitrate, ferric nitrate, ferrous chloride, ferric chloride, potassium ferrite, potassium ferrocyanide, potassium ferricyanide, and ferrocyanide iron, and the selection of the iron source reagent needs to ensure that it can adsorb and impregnate the surface of the product obtained in step 1), and ensure that it generates Fe3O4 during the air atmosphere heat treatment, and is not a regular selection.
[0013] In the above technical solution of the present application, the obtained Co3O4@Co3O4 / Fe3O4 yolk@eggshell structure nanoreactor is used in the fields of hydrogen production and oxygen catalysis, environmental pollutant degradation catalysis, petroleum cracking catalysis, and other fields involving confined space catalysis, as well as in the modeling method of confined catalytic molecular dynamics research.
[0014] In the above technical solution of the present application, the purity of the chemical reagents used is not less than analytical purity.
[0015] The method provided by the application realizes preparation of the egg yolk-egg shell structure Co3O4@Co3O4 / Fe3O4 composite new material, and the obtained advanced catalytic material has excellent catalytic activity. Molecular dynamics simulation shows that the diffusion coefficient of reactants in the confined space is reduced, and the contact probability of reactants and active sites is increased, thus revealing the potential mechanism of the confined effect synergistic heterogeneous catalysis. The method provided by the application has the advantages of simple process, convenient operation, low synthesis temperature, low energy consumption, low preparation cost, green and environmentally friendly reagents, non-toxicity, non-corrosiveness, and batch production. BRIEF DESCRIPTION OF DRAWINGS
[0016] Figure 1 is an XRD pattern of a representative sample.
[0017] Figure 2 is an SEM photo of a representative sample.
[0018] Figure 3 is a TEM photo of a representative sample.
[0019] Figure 4 is a catalytic oxidation performance evaluation of a representative sample.
[0020] Figure 5 is a molecular dynamics model of a representative sample. EMBODIMENT
[0021] Example 1:
[0022] 1) 30 mmol of cobalt naphthenate was dissolved in 60 mL of N,N dimethylformamide and 30 mL of N,N dimethylacetamide organic solvents, and solvent thermal reaction was carried out at 200 DEG C for 8 hours in a high-pressure reaction kettle; after cooling to room temperature, the precipitate was washed with anhydrous ethanol, and dried at 60 DEG C for standby use;
[0023] 2) 200 mL of deionized water was placed in a reaction container, and heated to 95 DEG C in a water bath; 0.25 g of the product obtained in step 1) was dispersed in the deionized water, and hydrolysis etching was carried out for 3 hours, then iron hexacyanoferrate was added for adsorption and impregnation for 1 hour; after cooling to room temperature, the precipitate was washed and dried at 80 DEG C, and then calcined at 500 DEG C for 3 hours in an air atmosphere, to obtain a Co3O4@Co3O4 / Fe3O4 egg yolk-egg shell structure nano reactor.
[0024] Example 2:
[0025] 1) 30 mmol of cobalt naphthenate was dissolved in 60 mL of N,N dimethylformamide and 30 mL of N,N dimethylacetamide organic solvents, and solvent thermal reaction was carried out at 200 DEG C for 8 hours in a high-pressure reaction kettle; after cooling to room temperature, the precipitate was washed with anhydrous ethanol, and dried at 60 DEG C for standby use;
[0026] 2) 100 mL of deionized water was placed in a reaction vessel, heated to 80°C in a water bath, 0.2 g of the product obtained in step 1) was dispersed in deionized water, hydrolytic etching for 2 hours, then FeSO4 adsorption and immersion for 2 hours, after cooling to room temperature, the precipitate was washed and dried at 60°C, then calcined at 300°C for 5 hours in an air atmosphere, to obtain a Co3O4@Co3O4 / Fe3O4 yolk@egg shell structure nanoreactor.
[0027] Example 3:
[0028] 1) 30 mmol of cobalt acetate was dissolved in 120 mL of n-propanol and 30 mL of isopropanol organic solvent, and a solvothermal reaction was carried out at 180°C for 12 hours in a high-pressure reaction kettle, after cooling to room temperature, the precipitate was washed with anhydrous ethanol, and dried at 70°C for standby use;
[0029] 2) 100 mL of deionized water was placed in a reaction vessel, heated to 90°C in a water bath, 0.1 g of the product obtained in step 1) was dispersed in deionized water, hydrolytic etching for 1.5 hours, then FeCl2 and FeCl3 adsorption and immersion for 1.5 hours, after cooling to room temperature, the precipitate was washed and dried at 80°C, then calcined at 500°C for 1 hour in an air atmosphere, to obtain a Co3O4@Co3O4 / Fe3O4 yolk@egg shell structure nanoreactor.
[0030] Example 4:
[0031] 1) 30 mmol of cobalt nitrate was dissolved in 90 mL of isopropanol and 24 mL of glycerol organic solvent, and a solvothermal reaction was carried out at 180°C for 6 hours in a high-pressure reaction kettle, after cooling to room temperature, the precipitate was washed with anhydrous ethanol, and dried at 60°C for standby use;
[0032] 2) 100 mL of deionized water was placed in a reaction vessel, heated to 90°C in a water bath, 0.2 g of the product obtained in step 1) was dispersed in deionized water, hydrolytic etching for 2 hours, then K3Fe(CN)6 adsorption and immersion for 1 hour, after cooling to room temperature, the precipitate was washed and dried at 60°C, then calcined at 400°C for 2 hours in an air atmosphere, to obtain a Co3O4@Co3O4 / Fe3O4 yolk@egg shell structure nanoreactor.
[0033] Example 5:
[0034] 1) 30 mmol of cobalt naphthenate was dissolved in 90 mL of n-propanol and 24 mL of pentanediol organic solvent, and a solvothermal reaction was carried out at 160°C for 10 hours in a high-pressure reaction kettle, after cooling to room temperature, the precipitate was washed with anhydrous ethanol, and dried at 70°C for standby use;
[0035] 2) 300 mL of deionized water was placed in a reaction vessel, heated to 90°C in a water bath, 0.5 g of the product obtained in step 1) was dispersed in deionized water, hydrolytic etching for 2.5 hours, then potassium ferrite and potassium ferrocyanide adsorption impregnation for 0.5 hours, after cooling to room temperature, the precipitate was washed and dried at 80°C, then calcined at 500°C for 3 hours in air atmosphere, to obtain Co3O4@Co3O4 / Fe3O4 yolk@egg shell structure nanoreactor.
[0036] Example 6:
[0037] 1) 30 mmol of cobalt isooctoate was dissolved in 90 mL of ethyl acetate and 30 mL of butyl acetate organic solvent, solvent thermal reaction was carried out at 120°C for 10 hours in a high-pressure reaction kettle, after cooling to room temperature, the precipitate was washed with anhydrous ethanol, dried at 60°C for standby;
[0038] 2) 100 mL of deionized water was placed in a reaction vessel, heated to 80°C in a water bath, 0.1 g of the product obtained in step 1) was dispersed in deionized water, hydrolytic etching for 2 hours, then ferric ferrocyanide adsorption impregnation for 0.5 hours, after cooling to room temperature, the precipitate was washed and dried at 60°C, then calcined at 450°C for 2 hours in air atmosphere, to obtain Co3O4@Co3O4 / Fe3O4 yolk@egg shell structure nanoreactor.
[0039] Example 7:
[0040] 1) 30 mmol of cobalt oxalate was dissolved in 90 mL of butanol and 45 mL of ethylene glycol organic solvent, solvent thermal reaction was carried out at 200°C for 8 hours in a high-pressure reaction kettle, after cooling to room temperature, the precipitate was washed with anhydrous ethanol, dried at 70°C for standby;
[0041] 2) 200 mL of deionized water was placed in a reaction vessel, heated to 80°C in a water bath, 0.3 g of the product obtained in step 1) was dispersed in deionized water, hydrolytic etching for 3 hours, then ferrous nitrate and ferric nitrate adsorption impregnation for 1 hour, after cooling to room temperature, the precipitate was washed and dried at 70°C, then calcined at 300°C for 1 hour in air atmosphere, to obtain Co3O4@Co3O4 / Fe3O4 yolk@egg shell structure nanoreactor.
Claims
1. A method for preparing a Co3O4@Co3O4 / Fe3O4 yolk@eggshell structured nanoreactor, characterized in that: 1) Dissolve a certain amount of cobalt salt in a certain volume of organic solvent. The organic solvent used is a combination of two of the following: ethanol, ethylene glycol, n-propanol, isopropanol, N,N-dimethylformamide, acetone, glycerol, pentanediol, butanol, tert-butanol, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethylene glycol monoethyl ether, formic acid, acetonitrile, N,N-dimethylformamide ammonia, tributyl methyl ethyl ether, and isopropyl acetate. The volume ratio of these two solvents is 2 to 4. The reaction is carried out in a high-pressure reactor at 120 to 200°C for 6 to 12 hours as a solvent heat. After cooling to room temperature, the precipitate is washed with anhydrous ethanol and dried at 60 to 80°C for later use. 2) Place 500-1000 mL of deionized water in a reaction vessel and heat it in a water bath to 80-95°C. Take 1 g of the product obtained in step 1) and disperse it in the above deionized water. Hydrolyze and etch for 1.5-3 hours, then add an iron source for adsorption and impregnation for 0.5-1.5 hours. After cooling to room temperature, wash the precipitate and dry it at 60-80°C. Then calcine it at 300-500°C in air for 1-5 hours to obtain a Co3O4@Co3O4 / Fe3O4 yolk@eggshell structured nanoreactor.
2. The preparation method of the Co3O4@Co3O4 / Fe3O4 yolk@eggshell structured nanoreactor according to claim 1, characterized in that: The cobalt salt used in step 1) is one or a combination of cobalt chloride, cobalt acetate, cobalt sulfate, cobalt naphthenate, cobalt nitrate, cobalt fluoride, cobalt oxalate, and cobalt isooctanoate.
3. The preparation method of the Co3O4@Co3O4 / Fe3O4 yolk@eggshell structured nanoreactor according to claim 1, characterized in that: In step 2), the ratio of the volume of deionized water to the mass of the product in step 1) is (500-1000) mL:1g. The iron source used is one or a combination of several of the following: ferrous sulfate, ferric sulfate, ferrous nitrate, ferric nitrate, ferrous chloride, ferric chloride, potassium ferrate, potassium ferrocyanide, potassium ferricyanide, and ferrous ferrocyanide.
4. A Co3O4@Co3O4 / Fe3O4 yolk@eggshell structured nanoreactor prepared by the method according to any one of claims 1 to 3.
5. The application of the Co3O4@Co3O4 / Fe3O4 yolk@eggshell structured nanoreactor as described in claim 4 in any one of the following aspects: hydrogen production and oxygen generation catalysis, environmental pollutant degradation catalysis, and petroleum cracking catalysis.
6. A method for modeling confined catalytic molecular dynamics, characterized in that, The method includes using the Co3O4@Co3O4 / Fe3O4 yolk@eggshell structured nanoreactor of claim 4 as a model.