An electrocatalyst material of organic molecule modified metal hydroxide and a preparation method and application thereof
By modifying metal hydroxide electrocatalyst materials with organic molecules, the problems of slow reaction kinetics and low catalytic efficiency in the electrocatalytic oxidation of cyclohexanone and cyclohexanol to prepare adipic acid have been solved, realizing the preparation of highly efficient and selective catalysts and the production of green chemicals.
Patent Information
- Application Number
- CN202510350298.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-24
- Publication Date
- 2025-12-12
- Estimated Expiration
- 2045-03-24
AI Technical Summary
In the existing technology, the process of electrocatalytic oxidation of cyclohexanone and cyclohexanol to prepare adipic acid has problems such as slow reaction kinetics, low catalytic efficiency, poor solubility of organic reactants in water, and poor catalytic selectivity. In addition, the large-scale preparation of catalysts is complicated.
Electrocatalyst materials that modify metal hydroxides with organic molecules form hydrophobic regions, enhancing the compatibility of organic molecules in aqueous solutions and optimizing the electronic structure of metal sites, thereby promoting electron transfer and molecular mass transfer processes.
A highly active and selective electrocatalytic process for the production of adipic acid using KAoil has been achieved, simplifying the catalyst preparation process. This process can efficiently catalyze the conversion of cyclohexanone and cyclohexanol to adipic acid at ambient temperature and pressure, and can be coupled with cathode hydrogen production to enhance the added value of the reaction products.
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Figure CN120060920B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the field of electrocatalytic organic synthesis, and particularly relates to an electrocatalyst material of an organic molecule modified metal hydroxide and a preparation method and application thereof, in particular, an application in the reaction of electrocatalytic oxidation of cyclohexanone and cyclohexanol to prepare adipic acid. BACKGROUND
[0002] Adipic acid, also known as fatty acid, is a white monoclinic crystal at room temperature, and is the most valuable dibasic acid among aliphatic dibasic acids, and is widely used in food, medicine and chemical industry and other fields. In 2020, the global demand for adipic acid was 3.17 million tons, with a market value of more than 7 billion US dollars. Among them, adipic acid is a key intermediate for the synthesis of nylon and polyurethane, and can be further processed to produce plasticizers, cosmetic additives, gelatin, lubricants, fertilizers, adhesives, pesticides, paper and wax, etc. At present, the industrial production of adipic acid still adopts the traditional catalytic oxidation method, using Cu as the catalyst, using HNO3 and NH4VO3 as the oxidant, and oxidizing cyclohexanone and cyclohexanol (collectively referred to as KAoil) to prepare adipic acid under the conditions of 0.1-0.4Mpa and 60-80℃. The strong acid heating conditions of this method put high requirements on the corrosion resistance of the production equipment, and the generation of nitrogen oxides such as N2O brings great harm to the environment, and the use of non-renewable fossil energy as fuel also does not meet the requirements of green and sustainable development.
[0003] Electrocatalytic oxidation of cyclohexanone and cyclohexanol to prepare adipic acid provides a sustainable way to solve the above problems. The use of renewable electric energy and water as an oxygen source avoids the use of strong acid and strong oxidant, and the electrocatalytic process at room temperature and pressure avoids the harsh reaction conditions of traditional catalytic oxidation. At the same time, the anodic oxidation reaction of electrocatalytic preparation of adipic acid can be coupled with cathodic hydrogen production, further improving the added value of the reaction product. Although there are many advantages, the process of electrocatalytic oxidation of KAoil to prepare adipic acid is faced with problems such as low catalytic efficiency due to slow reaction kinetics, poor solubility of organic reactants in water, and poor catalytic selectivity. The scale-up preparation of the catalyst also faces difficulties such as complicated synthesis steps.
[0004] Therefore, the efficient preparation of an adipic acid electro-synthesis catalyst with high activity and high selectivity is the key to realizing the scale-up synthesis of adipic acid. SUMMARY
[0005] To solve the problems and challenges in the prior art, the present application provides an organic molecule modified metal hydroxide electrocatalyst material, a preparation method and application thereof, which is a non-noble metal adipic acid electro-synthesis catalyst. The metal hydroxide catalyst provided by the present application has a unique organic molecule modification structure. The modified organic molecules form a hydrophobic interval, effectively enhancing the enrichment of cyclohexanone and cyclohexanol molecules around the catalyst, and improving the compatibility of the organic substrate molecules in the aqueous solution. At the same time, the Π-Π interaction between the organic molecules effectively improves the stability of the catalyst. The heteroatoms at the ends of the organic ligands are coordinated with the metal sites, optimizing the electronic structure of the metal sites, and promoting the electron transfer and molecular mass transfer processes in the catalytic process. These factors make the present application have excellent electrocatalytic performance for the preparation of adipic acid by KAoil.
[0006] The object of the present application can be achieved by the following solutions.
[0007] In a first aspect, the present application provides an organic molecule modified metal hydroxide electrocatalyst material, which comprises a substrate, a metal hydroxide loaded on the substrate, and an organic molecule modified on the metal hydroxide.
[0008] The N atom in the organic molecule is coordinated with the metal in the metal hydroxide, thereby being modified on the metal hydroxide.
[0009] According to some embodiments of the present application, the organic molecule (A) comprises one or more of phthalazine, 2,2-bipyridine, 4,4-bipyridine, 1,2-bis(4-pyridyl)ethane, and 5-NO2-1,10-phenanthroline.
[0010] According to some embodiments of the present application, the metal hydroxide comprises one or more of cobalt hydroxide, nickel hydroxide, iron hydroxide, cerium hydroxide, chromium hydroxide, and aluminum hydroxide.
[0011] According to some embodiments of the present application, the substrate can be selected from carbon cloth, graphite sheet, nickel foam, and copper foam. Various carriers can be used as deposition electrodes.
[0012] In a second aspect, the present application discloses a preparation method of an organic molecule modified metal hydroxide electrocatalyst material, which comprises the following steps:
[0013] The organic molecule (A) is added to an electrolyte containing a metal salt (B), and an electro-deposition is performed by using a three-electrode system, with the substrate material as a working electrode, thereby obtaining the electrocatalyst material.
[0014] According to some embodiments of the present application, the organic molecule (A) comprises one or more of phthalazine, 2,2-bipyridine, 4,4-bipyridine, 1,2-bis(4-pyridyl)ethane, and 5-NO2-1,10-phenanthroline.
[0015] According to some embodiments of the present application, the metal salt (B) is a nitrate salt of a metal, and the metal includes one or more of cobalt, nickel, iron, cerium, chromium, and aluminum.
[0016] According to some embodiments of the present application, the molar ratio of the organic molecule (A) to the metal salt (B) is 1:1 to 1:3.
[0017] According to some embodiments of the present application, the solubility of the metal salt (B) in the electrolyte is 0.1 to 0.3 M, and preferably 0.15 to 0.22 M.
[0018] According to some embodiments of the present application, the solvent in the electrolyte includes one or more of water and N,N-dimethylformamide, and preferably water and N,N-dimethylformamide.
[0019] According to some embodiments of the present application, during the electrodeposition, the electrode holder holds a substrate material as a working electrode, and the obtained electrocatalyst material is loaded on the substrate material. The deposition potential for the electrodeposition is -1 to -3 V, and the time is 180 to 220 s, and preferably the deposition potential is -2 V and the time is 200 s. An Ag / AgCl electrode is used as a reference electrode, and a Chenhua 760e workstation is used, and a constant potential deposition mode is selected, and the deposition potential is set to -2 V.
[0020] According to some embodiments of the present application, the temperature of the electrodeposition (synthesis temperature) is 20 to 30°C, and preferably room temperature 25°C.
[0021] According to some embodiments of the present application, the obtained electrocatalyst material is further subjected to washing and drying treatment. The solvent used in the washing includes one or more of water and ethanol. The drying method is drying at 50 to 70°C, and preferably 60°C.
[0022] According to some embodiments of the present application, the obtained electrocatalyst material does not need subsequent heat treatment.
[0023] In a third aspect, the present application also provides a use of the electrocatalyst material in a reaction for electrocatalytic oxidation to prepare adipic acid.
[0024] The raw material compounds of the reaction include cyclohexanol, cyclohexanone, and mixtures thereof. The present application uses the yield of adipic acid per unit time per unit area to evaluate the catalyst. The electrocatalyst material of the present application can be used to catalyze the oxidation of cyclohexanone and cyclohexanol to prepare adipic acid with high selectivity.
[0025] The reaction is a catalytic KAoil conversion reaction, and the electrocatalyst material is a working electrode. The adipic acid electro-synthesis catalyst of the present application has a unique integrated property, and can be directly used as a working electrode for catalytic KAoil conversion.
[0026] The present application is directly prepared by one-step electrodeposition method of organic molecule modified metal hydroxide catalyst supported on a carrier, and the catalyst is used for electrocatalytic cyclohexanone, cyclohexanol to prepare adipic acid, and high value-added chemicals are obtained.
[0027] Compared with the prior art, the present application has the following beneficial effects:
[0028] (1) The preparation process of the organic molecule modified metal hydrooxide integrated electrode material directly supported on the substrate is simple, easy to operate, and can be prepared on a large scale.
[0029] (2) The obtained catalyst can catalyze the industrial important reaction of cyclohexanone, cyclohexanol electro-synthesis to prepare adipic acid with high activity and high selectivity at a wide potential, and pure hydrogen can be obtained at the cathode, realizing green preparation of high value-added chemical products. BRIEF DESCRIPTION OF DRAWINGS
[0030] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments made with reference to the accompanying drawings:
[0031] Figure 1 is a synthesis schematic diagram;
[0032] Figure 2 is an X-ray diffraction pattern (XRD) of the 4,4'-bipyridine molecule modified nickel hydroxide catalyst deposited in Example 1 and a standard diffraction card (PDF card) of nickel hydroxide;
[0033] Figure 3 is a comparison of the yield per unit time per unit area of 4,4'-bipyridine molecule modified nickel hydroxide and nickel hydroxide catalyst for electrocatalytic cyclohexanone to prepare adipic acid at 1.43V-1.73V (vs. RHE);
[0034] Figure 4 is a comparison of the yield per unit time per unit area of phthalazine, 2,2-bipyridine, 1,2-di(4-pyridyl)ethane, 5-NO2-1,10-phenanthroline molecule modified nickel hydroxide and unmodified nickel hydroxide catalyst for electrocatalytic cyclohexanone to prepare adipic acid at 1.53V (vs. RHE);
[0035] Figure 5 is a comparison of the yield of 4,4'-bipyridine molecule modified double metal hydroxide and unmodified double metal hydroxide catalyst for electrocatalytic cyclohexanone to prepare adipic acid after two hours of electrolysis at 1.53V (vs. RHE);
[0036] Figure 6Comparison of the unit time and unit area yield of the electrocatalytic preparation of adipic acid from cyclohexanone at 1.53 V (vs. RHE) by sodium dodecyl sulfate and benzoate modified nickel hydroxide catalysts and 4,4'-bipyridine molecule modified nickel hydroxide catalysts. DETAILED DESCRIPTION
[0037] The present application will be described in detail below with reference to the drawings and specific examples. The following examples are implemented on the premise of the technical solutions of the present application, and provide detailed implementation modes and specific operation processes, which will help those skilled in the art to further understand the present application. It should be pointed out that the protection scope of the present application is not limited to the following examples, and several adjustments and improvements made on the premise of the concept of the present application all belong to the protection scope of the present application.
[0038] Example 1
[0039] In this embodiment, an organic molecule modified metal hydroxide catalyst is prepared by one-step electrodeposition, such as Figure 1 As shown in the figure, the electrodeposition preparation method of the 4,4'-bipyridine molecule modified nickel hydroxide catalyst is as follows:
[0040] (1) Treatment of the loaded substrate foam nickel: The foam nickel is ultrasonically treated in a 3M hydrochloric acid solution at room temperature to remove the oxide layer on the surface of the foam nickel, and then ultrasonically cleaned in ultrapure water to obtain a clean foam nickel substrate for standby.
[0041] (2) Preparation of the deposition solution (electrolyte): 4,4'-bipyridine molecules are dispersed in a 0.2M nickel nitrate solution, the solvent is a mixture of water and N,N-dimethylformamide (volume ratio 3:2), ultrasonic is used to promote dissolution, and a uniform transparent solution is obtained as the deposition solution, the molar ratio of 4,4'-bipyridine molecules to nickel nitrate is 1:2.
[0042] (3) Deposition process: The treated foam nickel is clamped as the working electrode by an electrode holder, an Ag / AgCl electrode is used as the reference electrode, a Chenhua 760e workstation is used, a constant potential deposition mode is selected, the deposition potential is set to -2V, and the time is set to 200s.
[0043] The X-ray diffraction pattern (XRD) of the obtained catalyst material (Bipy-Ni(OH)2) and the standard diffraction card (PDF card) of nickel hydroxide are as shown in the figure. Figure 2
[0044] Performance test:
[0045] The nickel hydroxide modified by 4,4'-bipyridine molecules prepared in Example 1 was taken as an example, and cyclohexanone was taken as a raw material. The nickel hydroxide catalyst loaded on the nickel foam substrate (without adding 4,4'-bipyridine molecules in the electrolyte) and the nickel hydroxide catalyst modified by 4,4'-bipyridine molecules were cut into one square centimeter, Pt sheet was selected as the counter electrode, Hg / HgO was selected as the reference electrode, and platinum electrode clamp was used to clamp the electrode material loaded with nickel hydroxide cut into a certain size. 1.5M aqueous sodium hydroxide solution was added to one side of the H-type electrolytic cell, and 0.1M cyclohexanone aqueous sodium hydroxide solution was added to the other side, and the corresponding electrodes were inserted into the corresponding positions of the H-type electrolytic cell. A certain electrolysis potential (1.43V, 1.53V, 1.63V, 1.73V vs. RHE) was applied, and the electrolysis time was set to 1 hour. After electrolysis, 100 microliters of the reaction electrolyte was taken and added to a nuclear magnetic tube, and after adding a certain amount of internal standard dimethyl sulfoxide and D2O, nuclear magnetic resonance was used for quantification. The results are shown in Table 2. Figure 3 As shown, compared with the nickel hydroxide catalyst, the nickel hydroxide catalyst modified by 4,4'-bipyridine molecules showed higher catalytic activity.
[0046] Example 2
[0047] In this example, an organic molecule modified metal hydroxide catalyst was prepared by one-step electrodeposition method. The electrodeposition preparation method of phthalazine, 2,2'-bipyridine, 1,2-di(4-pyridyl)ethane, and 5-NO2-1,10-phenanthroline molecule modified metal nickel hydroxide catalyst is as follows:
[0048] (1) Treatment of the loading substrate nickel foam: The nickel foam was ultrasonically treated in a 3M hydrochloric acid solution at room temperature to remove the oxide layer on the surface of the nickel foam, and then ultrasonically cleaned in ultrapure water to obtain a clean nickel foam substrate for standby.
[0049] (2) Preparation of deposition solution (electrolyte): As shown in Table 1, phthalazine (Ph), 2,2'-bipyridine (2,2'-Bipy), 1,2-di(4-pyridyl)ethane (Bpa), and 5-NO2-1,10-phenanthroline (Phen-NO2) molecules were dispersed in a 0.2M nickel nitrate solution, respectively, and ultrasonically dissolved to obtain a uniform transparent solution as a deposition solution. The molar ratio of the molecules to nickel nitrate was 1:2.
[0050] Table 1 Different organic molecules
[0051] Catalyst Organic molecule Metal salt (0.2 M) Ph modified catalyst Phthalazine (Ph) Nickel nitrate 2,2'-Bipy modified catalyst 2,2'-Bipyridine (2,2'-Bipy) Nickel nitrate Bpa modified catalyst 1,2-Bis(4-pyridyl)ethane (Bpa) Nickel nitrate Phen-NO2 modified catalyst 5-NO2-1,10-phenanthroline (Phen-NO2) Nickel nitrate
[0052] (3) Deposition process: The electrode holder clamps the treated foam nickel as the working electrode, and Ag / AgCl electrode as the reference electrode. The Chenhua 760e workstation is selected to set the deposition potential at -2 V and the time at 200 s.
[0053] Performance test
[0054] As an example, the various molecularly modified nickel hydroxide prepared in Example 2 was used as the catalyst, and cyclohexanone was used as the reaction raw material. A square centimeter of the nickel hydroxide catalyst supported on the foam nickel substrate and the four types of molecularly modified nickel hydroxide catalysts were cut, a Pt sheet was selected as the counter electrode, Hg / HgO was used as the reference electrode, and a platinum electrode holder was used to clamp the electrode material with the nickel hydroxide supported thereon to a certain size. On one side of the H-type electrolytic cell, 1.5 M aqueous sodium hydroxide solution was added, and on the other side, 0.1 M cyclohexanone aqueous sodium hydroxide solution was added. The corresponding electrodes were inserted into the corresponding positions of the H-type electrolytic cell. A certain electrolysis potential (1.53 V vs. RHE) was applied, and the electrolysis time was set to 1 hour. After the electrolysis was completed, 100 microliters of the reacted electrolyte was taken and added to a nuclear magnetic tube. After adding a certain amount of internal standard dimethyl sulfoxide and D2O, nuclear magnetic resonance was used for quantification. The results are shown in Table 1. Figure 4 As shown in Table 1, compared with the nickel hydroxide catalyst, the molecularly modified nickel hydroxide catalysts showed higher catalytic activity. (The molecularly modified nickel hydroxide catalysts are represented by the abbreviations of the molecules)
[0055] Example 3
[0056] In this example, a one-step electrodeposition method was used to prepare 4,4’-bipyridine molecularly modified double-metal hydroxide catalysts. The electrodeposition preparation method of the 4,4’-bipyridine molecularly modified double-metal nickel hydroxide catalyst is as follows:
[0057] (1) Treatment of the foam nickel support: The foam nickel was ultrasonically treated in a 3 M hydrochloric acid solution at room temperature to remove the oxide layer on the surface of the foam nickel, and then ultrasonically cleaned in ultrapure water to obtain a clean foam nickel substrate for standby use.
[0058] (2) Preparation of the deposition solution (electrolyte): As shown in Table 2, the 4,4’-bipyridine molecules were dispersed in solutions containing different nitrate salts, respectively, and ultrasonically dissolved to obtain a uniform transparent solution as the deposition solution. The molar ratio of the bipyridine molecules to nickel nitrate was 1:2.
[0059] Table 2 Different metal salts
[0060]
[0061] (3) Deposition process: The electrode holder clamped the treated foam nickel as the working electrode, Ag / AgCl electrode as the reference electrode, and the Chenhua 760e workstation was used to select the constant potential deposition mode and set the deposition potential to -2 V.
[0062] Performance test
[0063] The 4,4'-bipyridine molecule modified double-metal hydroxide prepared in Example 3 was taken as an example, and cyclohexanone was used as the reaction raw material. A square centimeter of the double-metal hydroxide catalyst loaded on the foam nickel substrate was cut, a Pt sheet was selected as the counter electrode, Hg / HgO was used as the reference electrode, and a platinum electrode holder was used to clamp the electrode material loaded with nickel hydroxide cut to a certain size. On one side of the H-type electrolytic cell, 1.5 M aqueous sodium hydroxide solution was added, and on the other side, 0.1 M cyclohexanone aqueous sodium hydroxide solution was added. The corresponding electrodes were inserted into the corresponding positions of the H-type electrolytic cell. A certain electrolysis potential (1.53 V vs. RHE) was applied, and the electrolysis time was set to 2 hours. After the electrolysis was completed, 100 microliters of the reacted electrolyte was taken and added to a nuclear magnetic tube. After adding a certain amount of internal standard dimethyl sulfoxide and D2O, nuclear magnetic resonance was used for quantification. The results are shown in Table 1. Figure 5 As shown in Table 1, compared with the unmodified double-metal hydroxide catalyst, the double-metal hydroxide catalyst with molecular modification showed higher catalytic activity.
[0064] Comparative Example 1
[0065] This comparative example provides a molecularly modified metal hydroxide, and the preparation method is basically the same as that of Example 1, except that 4,4'-bipyridine is replaced by sodium dodecyl sulfate of equal molar amount to obtain a dodecyl sulfate modified nickel hydroxide material (SDS-Ni(OH)2).
[0066] Comparative Example 2
[0067] This comparative example provides a molecularly modified metal hydroxide, and the preparation method is basically the same as that of Example 1, except that 4,4'-bipyridine is replaced by sodium benzoate to obtain a benzoate modified nickel hydroxide (Ben-Ni(OH)2).
[0068] Performance test
[0069] The two different molecularly modified samples obtained in the comparative examples were compared with the 4,4'-bipyridine modified sample in terms of performance test, and the results are shown in Table 2. Figure 6 As shown in Table 2, the catalytic performance of the 4,4'-bipyridine molecule modified nickel hydroxide sample is better than that of the samples in the comparative examples.
[0070] The specific embodiments of the present application are described above. It needs to be understood that the present application is not limited to the specific embodiments described above, and various modifications or changes can be made by those skilled in the art within the scope of the claims, which do not affect the essence of the present application.
Claims
1. Use of an electrocatalyst material of organic molecule modified metal hydroxide in a reaction for electrocatalytic oxidation preparation of adipic acid, characterized in that, The electrocatalyst material comprises a substrate, a metal hydroxide loaded on the substrate, and an organic molecule modified on the metal hydroxide; The N atom in the organic molecule is coordinated with the metal in the metal hydroxide, so as to be modified on the metal hydroxide; The organic molecule comprises one or more of phthalazine, 2,2-bipyridine, 4,4-bipyridine, 1,2-bis(4-pyridyl)ethane, and 5-NO2-1,10-phenanthroline; The metal hydroxide comprises one or more of cobalt hydroxide, nickel hydroxide, iron hydroxide, cerium hydroxide, chromium hydroxide, and aluminum hydroxide.
2. Use according to claim 1, wherein The substrate comprises one of carbon cloth, graphite sheet, nickel foam, and copper foam.
3. The use according to claim 1, wherein The preparation method of the electrocatalyst material comprises the following steps: The organic molecule is added into an electrolyte containing a metal salt, a substrate material is used as a working electrode, and electrodeposition is performed by using a three-electrode system, so as to obtain the electrocatalyst material.
4. The use according to claim 3, wherein the compound is ###0002### The metal salt is a nitrate of the metal; the metal comprises one or more of cobalt, nickel, iron, cerium, chromium, and aluminum.
5. The use according to claim 3, wherein the compound is ###0002### The molar ratio of the organic molecule to the metal salt is 1:1 to 1:
3.
6. The use according to claim 3, wherein the compound is ###0002### In the electrolyte, the solubility of the metal salt is 0.1 to 0.3 M.
7. The use according to claim 3, wherein the compound is ###0002### The solvent in the electrolyte comprises one or more of water and N,N-dimethylformamide.
8. The use according to claim 3, wherein the compound is ###0002### The deposition potential for the electrodeposition is -1 to -3 V, and the time is 180 to 220 s.