Composite electrocatalyst, preparation method thereof and application of composite electrocatalyst in preparation of organic acid salt by electrocatalytic oxidation of alcohol compound
A Ni/Pd/foam metal composite electrocatalyst was prepared by solvothermal method and electrodeposition technology, which solved the problems of high carbon emissions and low selectivity in the conversion of alcohols and achieved efficient and low carbon conversion of alcohols to organic acid salts. The catalyst exhibited excellent catalytic performance and high selectivity at room temperature and pressure.
Patent Information
- Application Number
- CN202511732924.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-24
- Publication Date
- 2026-02-24
AI Technical Summary
Existing technologies for converting alcohols into organic acid salts suffer from high carbon emissions, high energy consumption, high equipment costs, and low selectivity of target products. Traditional methods are difficult to meet the requirements of green, environmentally friendly, low-carbon, and high-efficiency processes.
A Ni/Pd/foam metal composite electrocatalyst was prepared using a solvothermal method and electrodeposition technology. By precisely controlling the structure and morphology of Ni and Pd nanoparticles on the foam metal surface, the electrocatalytic oxidation of alcohols under alkaline conditions was achieved, generating high-value-added organic acid salts.
The catalyst achieves efficient conversion of alcohols to organic acid salts at ambient temperature and pressure, exhibiting excellent catalytic performance and high selectivity, with an alcohol conversion rate of over 75%.
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Figure CN121556071A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of electrochemical catalysis technology, specifically including a composite electrocatalyst, its preparation method, and its application in the electrocatalytic oxidation of alcohols to prepare organic acid salts. Background Technology
[0002] The conversion of alcohols into organic acid salts has significant practical implications, enabling efficient resource utilization and green transformation. From a resource utilization perspective, this conversion transforms biomass-based alcohols into high-value-added organic acid salts, expanding biomass resource utilization pathways and alleviating dependence on fossil resources. From an industrial application perspective, the resulting organic acid salts are key intermediates in the chemical, pharmaceutical, and food industries, and can be used to synthesize solvents, plasticizers, and preservatives. They can also serve as fuel cells, promoting the development of green energy. From an environmental perspective, the conversion process employs mild electrocatalytic conditions, reducing pollution from traditional chemical processes, aligning with green chemistry principles, and contributing to the recycling of carbon resources.
[0003] Traditional technologies for converting alcohols to organic acid salts often rely on high temperature, high pressure, and fossil fuels / chemical oxidants, resulting in high carbon emissions, high energy consumption, and high equipment costs. Furthermore, the vigorous reactions can easily lead to over-oxidation of alcohols, producing numerous byproducts and exhibiting low selectivity for the target product. These traditional technologies no longer meet the current societal demands for green, environmentally friendly, low-carbon, and efficient processes, thus necessitating the development of new conversion technologies to address these issues. Electrocatalysis, on the other hand, can utilize renewable green electricity to achieve near-zero carbon emissions, reduce hazardous waste, and promote the carbon cycle, better aligning with the needs of sustainable development. However, currently, there are relatively few reported electrocatalysts capable of efficiently and selectively converting alcohols to organic acid salts. Summary of the Invention
[0004] To address the aforementioned problems in the existing technology, the first objective of this invention is to provide a method for preparing a composite electrocatalyst. This method first prepares Pd / foam metal using a solvothermal synthesis method, and then, based on electrodeposition technology, further deposits Ni-loaded onto the Pd / foam metal substrate. 2+ Ni / Pd / foam metal was prepared in this way, and the structure and morphology of Ni on the surface of Pd / foam metal were precisely controlled by adjusting the parameters of solvothermal synthesis and electrodeposition techniques.
[0005] A second objective of this invention is to provide a composite electrocatalyst.
[0006] The third objective of this invention is to provide an application of the above-mentioned composite electrocatalyst in the electrocatalytic oxidation of alcohols to prepare organic acid salts.
[0007] The fourth objective of this invention is to provide an electrolytic cell system for the electrocatalytic oxidation of alcohols to prepare organic acid salts. In this electrolytic cell system, Ni / Pd / foam metal is used as a catalyst, and under alkaline conditions, the conversion of alcohols to organic acid salts can be achieved at room temperature and pressure through electrocatalytic oxidation.
[0008] The fifth objective of this invention is to provide a method for the electrocatalytic oxidation of alcohols to prepare organic acid salts. In this method, a three-electrode electrolytic cell assembled with the aforementioned composite electrocatalyst as the working electrode can catalytically oxidize alcohols in an alkaline electrolyte to generate high-value-added organic acid salts under electrocatalysis.
[0009] To achieve the first objective mentioned above, the technical solution adopted by the present invention includes: This invention discloses a method for preparing a composite electrocatalyst, comprising the following steps: Using soluble palladium salt, reducing agent, and first surfactant as raw materials, and foam metal as substrate material, Pd nanoparticles are loaded onto foam metal using a solvothermal method in a weakly acidic environment, denoted as Pd / foam metal. Using Pd / foam metal as the working electrode substrate, Ni nanoparticles were deposited in situ on the surface of Pd / foam metal by electrodeposition under the action of supporting electrolyte, soluble nickel salt and second surfactant. This is referred to as Ni / Pd / foam metal.
[0010] The above preparation method can be divided into two parts. The first is the solvothermal method for preparing Pd / foam metal. Based on the solvothermal synthesis method, Pd is grown in situ on the surface of Nifoam substrate to prepare Pd / foam metal. By controlling key solvothermal process parameters such as solvent type, reaction temperature, and reaction time, Pd / foam metal composite materials with specific microstructures can be controlled. The second is the electrodeposition method for preparing Ni / Pd / foam metal. Based on electrodeposition technology, Ni... 2+ Ni / Pd / foam metal was prepared by deposition loading on Pd / foam metal substrates. The influence mechanism of electrodeposition potential, current density and deposition time on the electrodeposition process of Ni nanoparticles was analyzed. The thermodynamic (such as deposition potential window) and kinetic (such as ion diffusion rate and electron transfer efficiency) parameters of electrodeposition were precisely controlled to achieve precise control of the structure and morphology of Ni on the Pd / foam metal surface. Finally, it showed excellent catalytic ability in the electrocatalytic oxidation of alcohols to prepare organic acid salts.
[0011] Furthermore, the soluble palladium salt serves as the Pd in the solvothermal reaction system. 2+The precursor is selected from one or more of PdCl2, Pd(NO)2, Na2PdCl4, and Pd(NH3)4(NO3)2; the reducing agent is selected from one or more of ascorbic acid, ethylene glycol, and formaldehyde. Furthermore, it was discovered that through Pd 2+ Screening of precursors and reducing agents allows for precise control of Pd. 2+ →Pd 0 The thermodynamic driving force of the reduction process ensures that the reduction process has a suitable spontaneous tendency; The first surfactant mainly affects the crystal growth rate and morphology in the solvothermal reaction system, and is selected from hexadecyltrimethylammonium bromide and / or sodium dodecyl sulfate. By optimizing the acid-base conditions of the solvothermal reaction (for example, by controlling the addition of citric acid to change the system into a weakly acidic environment, with the pH controlled at approximately 3-6), the protonation degree and charge state of the first surfactant molecule are regulated, thereby affecting the crystal growth rate and morphology. The foam metal is selected from one or more of foam nickel, foam cobalt, foam iron, and foam copper.
[0012] Furthermore, the mass ratio of the soluble palladium salt to the reducing agent is 1:1 to 1:10; for example, the mass ratio of the soluble palladium salt to the reducing agent can be 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, etc.
[0013] Furthermore, the mass ratio of the soluble palladium salt to the first surfactant is 1:1 to 1:5; for example, the mass ratio of the soluble palladium salt to the first surfactant can be 1:1, 1:2, 1:3, 1:4, 1:5, etc.
[0014] Furthermore, the mass ratio of the soluble palladium salt to the foam metal is 1:10 to 1:40; for example, the mass ratio of the soluble palladium salt to the foam metal can be 1:10, 1:20, 1:30, 1:40, etc.
[0015] Furthermore, the reaction temperature of the solvothermal method is 40-100°C. o C, reaction time is 0.5-2h.
[0016] Furthermore, the solvent used in the solvothermal method is N,N-dimethylformamide, ethylene glycol, glycerol, or dimethyl sulfoxide, etc., and can be mixed with water in an appropriate proportion, with a volume ratio ranging from 1:1 to 10:1. If ethylene glycol or glycerol is used in the solvothermal method, then ethylene glycol or glycerol participates in the reaction process as both a solvent and a reducing agent in this system. Of course, if N,N-dimethylformamide or dimethyl sulfoxide is selected as the solvent, a reducing agent still needs to be added to participate in the reaction process.
[0017] Furthermore, the concentration range of the soluble palladium salt in the reaction system in the solvothermal method is 1-10 mmol / L.
[0018] It should be noted that after the solvothermal reaction, post-treatment methods such as high-temperature calcination or solvent extraction are used to remove the residual first surfactant on the surface of the Pd nanoparticles, ensuring that the active sites on the surface of the Pd nanoparticles are fully exposed. In addition, before the electrodeposition operation, the Pd / foam metal working electrode substrate should be electrochemically activated, that is, the native oxide layer and physically adsorbed impurities on the substrate surface should be removed using cyclic voltammetry scanning mode.
[0019] The electrodeposition process employs a constant voltage mode, and a constant temperature water bath is used during deposition to maintain a stable electrolyte temperature, eliminating the interference of temperature fluctuations on ion diffusion rate and electron transfer efficiency.
[0020] Furthermore, the soluble nickel salt is selected from one or more of NiCl2, Ni(NO3)2, NiSO4, and NiBr2; The supporting electrolyte is selected from NaCl and / or Na2SO4; The second surfactant is selected from polyvinylpyrrolidone and / or hexadecyltrimethylammonium bromide.
[0021] Furthermore, the mass ratio of the soluble nickel salt to the second surfactant is 1:1 to 1:5; for example, the mass ratio of the soluble nickel salt to the second surfactant can be 1:1, 1:2, 1:3, 1:4, 1:5, etc.
[0022] Furthermore, the mass ratio of the soluble nickel salt to Pd / foam metal is 1:10-1:40; for example, the mass ratio of the soluble nickel salt to Pd / foam metal can be 1:10, 1:20, 1:30, 1:40, etc.
[0023] Furthermore, the electrodeposition process employs a constant voltage mode, with the electrode potential remaining constant within a certain range of -0.3 to -0.6 V vs. RHE, and the electrodeposition time lasting 10-60 min.
[0024] It should be noted that after the electrodeposition process is completed, there are two post-processing steps to improve the performance of Ni / Pd / Nifoam. The first step is to remove the weakly adsorbed second surfactant on the surface by electrochemical cleaning, and the second step is to further remove the strongly adsorbed residual organic matter by calcination.
[0025] Furthermore, the calcination temperature is 250-350°C. o C, the calcination time is 1-2 h.
[0026] To achieve the second objective mentioned above, the technical solution adopted by the present invention includes: This invention discloses a composite electrocatalyst prepared by the preparation method described above.
[0027] Furthermore, the loading of Pd nanoparticles on the metal foam is 1-10 mg / cm³. 2 ; The loading of Ni nanoparticles on the Pd / foam metal surface is 0.5-5 mg / cm³. 2 .
[0028] Furthermore, the atomic ratio of Pd to Ni in the composite electrocatalyst is 1:0.4-1:4.
[0029] When the sizes of Ni and Pd nanoparticles are controlled to a comparable level (approximately 5-10 nm), they form a strongly interacting interface contact region. Through the directional transfer of electrons at the interface, the electronic structure of the two nanoparticles is synergistically optimized and controlled.
[0030] To achieve the third objective mentioned above, the technical solution adopted by the present invention includes: This invention discloses the application of the above-mentioned composite electrocatalyst in the electrocatalytic oxidation of alcohols to prepare organic acid salts.
[0031] To achieve the fourth objective mentioned above, the technical solution adopted by the present invention includes: This invention discloses an electrolytic cell system for the electrocatalytic oxidation of alcohols to prepare organic acid salts, comprising a composite electrocatalyst as described above and an alkaline electrolyte containing alcohols.
[0032] Furthermore, the alcohol compound is selected from one of methanol, ethanol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, glycerol, 1,3-butanediol, and 1,4-butanediol; The organic acid salt is formate, acetate, glycolate, 2-hydroxypropionate, 3-hydroxypropionate, 2,3-dihydroxypropionate, 3-hydroxybutyrate, or 4-hydroxybutyrate.
[0033] To achieve the fifth objective mentioned above, the technical solution adopted by the present invention includes: This invention discloses a method for preparing organic acid salts by electrocatalytic oxidation of alcohols. The electrocatalytic oxidation of alcohols is controlled by a CHI760E electrochemical workstation, using an H-type electrolytic cell with a three-electrode setup, and includes the following steps: A three-electrode electrolytic cell is assembled with a working electrode, a counter electrode, a reference electrode, and an alkaline electrolyte containing alcohols. An electrocatalytic reaction is carried out by applying voltage, and the alcohols are oxidized at the working electrode to generate the corresponding organic acid salts. The working electrode includes the composite electrocatalyst described above.
[0034] Furthermore, the reference electrode is selected from Hg / HgO electrodes.
[0035] Furthermore, the counter electrode is selected from Pt sheet electrodes.
[0036] Furthermore, during electrocatalytic oxidation, the applied voltage is in the range of 0.6-1 V vs. RHE.
[0037] All potentials in the electrocatalytic oxidation of alcohols were calibrated with reference to a reversible hydrogen electrode (RHE). For ease of calculation, the geometric surface area of the Ni / Pd / foam metal catalyst was uniformly cut to 1 cm². 2 and using 1 cm 2 Current density was calculated based on the geometric surface area, and all experiments were conducted at room temperature and pressure. Electrochemical tests included: linear sweep voltammetry and potentiostatic electrolysis.
[0038] Beneficial effects of this invention: This invention provides a method for preparing a composite electrocatalyst with mild reaction conditions and excellent catalytic activity. In this method, Pd nanoparticles are first grown in situ on a Nifoam substrate using a solvothermal method. The growth rate, morphology, and distribution of the Pd nanoparticles on the Nifoam substrate are precisely controlled by screening the type and amount of soluble palladium salt, reducing agent, and first surfactant, as well as by controlling the solvothermal reaction conditions. Then, Ni nanoparticles are deposited in situ on the Pd / Nifoam surface using electrodeposition. Uniform deposition of Ni nanoparticles is effectively achieved by controlling the soluble nickel salt, second surfactant, and electrodeposition process conditions. Under the combined action of Ni and Pd nanoparticles, excellent catalytic performance is exhibited in the electrocatalytic system.
[0039] An electrolytic cell system for the electrocatalytic oxidation of alcohols to organic acid salts was constructed using the composite electrocatalyst prepared in this invention as the working electrode. This electrolytic cell system employs an H-type electrolytic cell with a three-electrode configuration (including the composite electrocatalyst prepared in this invention as the working electrode, an Hg / HgO electrode as the reference electrode, and a Pt sheet electrode as the counter electrode). An alkaline electrolyte containing alcohols was selected. Under electrochemical oxidation, the conversion of alcohols to organic acid salts can be achieved at room temperature and pressure. Test results show that this invention exhibits excellent electrocatalytic performance for various alcohols (including methanol, ethanol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, glycerol, 1,3-butanediol, and 1,4-butanediol), with a selectivity exceeding 75%. Attached Figure Description
[0040] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.
[0041] Figure 1 The XRD pattern of the Ni / Pd / Nifoam catalyst prepared in Example 1 is shown.
[0042] Figure 2 Transmission electron microscopy and energy dispersive spectroscopy analysis of the Ni / Pd / Nifoam catalyst prepared in Example 1 are shown.
[0043] Figure 3 The image shown is a high-magnification transmission electron microscope image of the Ni / Pd / Nifoam catalyst prepared in Example 1.
[0044] Figure 4 The linear sweep voltammetric curves of the Ni / Pd / Nifoam catalyst prepared in Example 1 for the electrocatalytic oxidation of methanol to sodium formate and the results before and after electrolysis of the methanol solution are shown. 1 H NMR spectrum, in which... Figure 4 In the figure, a is the linear sweep voltammetry curve, and b is the curve before electrolysis of the methanol solution. 1 H NMR spectrum, c represents the amount of methanol solution after electrolysis with 3300 coulombs. 1 H NMR spectrum.
[0045] Figure 5 The linear sweep voltammetric curves of the Ni / Pd / Nifoam catalyst prepared in Example 1 for the electrocatalytic oxidation of ethanol to sodium acetate, as well as the curves before and after electrolysis of the ethanol solution, are shown. 1 H NMR spectrum, in which... Figure 5 In the figure, a is the linear sweep voltammetry curve, and b is the curve before electrolysis of the ethanol solution. 1 H NMR spectrum, c represents the amount of ethanol solution after electrolysis with 1800 coulombs. 1 H NMR spectrum.
[0046] Figure 6 The linear sweep voltammetric curves of the Ni / Pd / Nifoam catalyst prepared in Example 1 for the electrocatalytic oxidation of ethylene glycol to sodium glycolate, as well as the curves before and after electrolysis of the ethylene glycol solution, are shown. 1 H NMR spectrum, in which... Figure 6 In the figure, a is the linear sweep voltammetry curve, and b is the ethylene glycol solution before electrolysis. 1 H NMR spectrum, c represents the amount of ethylene glycol solution after electrolysis with 10600 coulombs. 1 H NMR spectrum.
[0047] Figure 7The linear sweep voltammetry curves for the electrocatalytic oxidation of 1,2-propanediol to sodium 2-hydroxypropionate using the Ni / Pd / Nifoam catalyst prepared in Example 1 are shown, along with the results before and after electrolysis of the 1,2-propanediol solution. 1 H NMR spectrum, in which Figure 7 In the figure, a is the linear sweep voltammetry curve, and b is the curve before electrolysis of the 1,2-propanediol solution. 1 H NMR spectrum, c represents the result of electrolysis of 1,2-propanediol solution with a charge of 5600 coulombs. 1 H NMR spectrum.
[0048] Figure 8 The linear sweep voltammetry curves for the electrocatalytic oxidation of 1,3-propanediol to sodium 3-hydroxypropionate using the Ni / Pd / Nifoam catalyst prepared in Example 1 are shown, along with the results before and after electrolysis of the 1,3-propanediol solution. 1 H NMR spectrum, in which Figure 8 In the figure, a is the linear sweep voltammetry curve, and b is the curve before electrolysis of the 1,3-propanediol solution. 1 H NMR spectrum, c represents the result of electrolysis of 1,3-propanediol solution with a charge of 6500 coulombs. 1 H NMR spectrum.
[0049] Figure 9 The linear sweep voltammetry curves for the electrocatalytic oxidation of glycerol to sodium 2,3-dihydroxypropionate using the Ni / Pd / Nifoam catalyst prepared in Example 1 are shown, along with the results before and after electrolysis of the glycerol solution. 1 H NMR spectrum, in which Figure 9 In the figure, a is the linear sweep voltammetry curve, and b is the glycerol solution before electrolysis. 1 H NMR spectrum, c represents the electrolysis charge of glycerol solution after 3070 coulombs. 1 H NMR spectrum.
[0050] Figure 10 The linear sweep voltammetry curves for the electrocatalytic oxidation of 1,3-butanediol to sodium 3-hydroxybutyrate using the Ni / Pd / Nifoam catalyst prepared in Example 1 are shown, along with the results before and after electrolysis of the 1,3-butanediol solution. 1 H NMR spectrum, in which Figure 10 In the figure, a is the linear sweep voltammetry curve, and b is the curve before electrolysis of the 1,3-butanediol solution. 1 H NMR spectrum, c represents the result of electrolysis of 1,3-butanediol solution with a charge of 2400 coulombs. 1 H NMR spectrum.
[0051] Figure 11The linear sweep voltammetry curves for the electrocatalytic oxidation of 1,4-butanediol to sodium 4-hydroxybutyrate using the Ni / Pd / Nifoam catalyst prepared in Example 1 are shown, along with the results before and after electrolysis of the 1,4-butanediol solution. 1 H NMR spectrum, in which... Figure 11 In the figure, a is the linear sweep voltammetry curve, and b is the curve before electrolysis of the 1,4-butanediol solution. 1 The 1H NMR spectrum, c represents the result of electrolysis of 1,4-butanediol solution with a charge of 6360 coulombs. 1 H NMR spectrum. Detailed Implementation
[0052] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments and accompanying drawings, further clarifies the invention. It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
[0053] In addition, unless otherwise specified, all raw materials used in this invention can be obtained commercially available. Any range described in this invention includes the end value and any value between the end values, as well as any subrange formed by the end value or any value between the end values.
[0054] In a specific embodiment, aqueous NMR was used. 1 H-spectroscopy was used for qualitative and quantitative analysis of the organic acid salts in the product; hydrogen gas was used for qualitative and quantitative analysis by gas chromatography and water displacement gas collection method.
[0055] Example 1 Using Ni foam (1cm × 2cm) as a carrier, a mixed solution of ethylene glycol and water (18mL ethylene glycol + 2mL water) was used as the solvothermal reaction environment. Ethylene glycol also served as a reducing agent. Citric acid was used to adjust the pH of the solvothermal reaction environment to 4-5. Na₂PdCl₄ was used as the Pd... 2+ The source (concentration in the system was 2.5 mmol / L), sodium dodecyl sulfate (concentration in the system was 3 mmol / L) was used as the first surfactant, the solvothermal reaction temperature was 60 °C, and the reaction time was 1 h. After the solvothermal reaction, it was calcined at 250 °C for 2 h under Ar atmosphere to prepare Pd / Nifoam.
[0056] An H-type three-electrode electrolytic cell was used, with Pd / Nifoam as the working electrode, a saturated calomel electrode as the reference electrode, a carbon rod electrode as the counter electrode, and Na2SO4 as the supporting electrolyte (concentration of 0.3 mol / L and volume of 50 mL). NiSO4 was used as the Ni... 2+Ni / Pd / Nifoam was prepared by using a source (0.6 mmol / L) and a second surfactant (0.6 mmol / L). The electrodeposition potential was kept constant at -0.5 V vs. RHE, and the electrodeposition time was 40 min. After electrodeposition, cyclic voltammetry was performed for 3 minutes (scanning range 0.2-1 V vs. RHE), followed by calcination at 250 °C for 2 hours under Ar atmosphere.
[0057] Figure 1 The XRD pattern of the Ni / Pd / Nifoam catalyst prepared in Example 1 is shown. Figure 1 The Ni / Pd / Nifoam catalyst has been successfully prepared.
[0058] Figure 2 Transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) analyses of the Ni / Pd / Nifoam catalyst prepared in Example 1 are shown. As can be seen from the figure, Ni nanoparticles and Pd nanoparticles are uniformly dispersed, with a molar ratio of Ni to Pd of approximately 1:2.
[0059] Figure 3 The image shows a high-magnification transmission electron microscope (TEM) image of the Ni / Pd / Nifoam catalyst prepared in Example 1. As can be seen from the image, the Ni nanoparticles and Pd nanoparticles are similar in size, both being 5-10 nm, and both types of nanoparticles expose (111) crystal planes. Furthermore, the two types of nanoparticles form a relatively dense interface rather than a simple contact composite. This will facilitate strong interactions between the two, achieving synergistic optimization of the electronic structure of the two nanoparticles through the directional transfer of interfacial electrons, ultimately promoting the electrocatalytic oxidation performance of alcohol compounds.
[0060] An electrolytic cell system for the electrocatalytic oxidation of alcohols to prepare organic acid salts was constructed. This system employed an H-type three-electrode electrolytic cell, with the following electrode configuration: a composite electrocatalyst Ni / Pd / Nifoam as the working electrode, an Hg / HgO electrode as the reference electrode, and a Pt sheet electrode as the counter electrode. An alkaline electrolyte containing alcohols was used. Under electrochemical oxidation, the conversion of alcohols to organic acid salts was achieved at room temperature and pressure. The electrocatalytic oxidation results are summarized in Table 1. 1 See the H NMR spectrum. Figures 4 to 11 .
[0061] Example 2 The catalyst preparation process is the same as in Example 1, except that in the solvothermal preparation of Pd / Nifoam, citric acid was not used to adjust the pH of the thermal reaction environment of the solution (pH about 6-7, but not 6), and the first surfactant was not added.
[0062] Example 3 The catalyst preparation process is the same as in Example 1, except that no second surfactant is added during the electrodeposition preparation of Ni / Pd / Nifoam.
[0063] Comparative Example 1 The catalyst preparation process is the same as in Example 1, except that the electrocatalyst Pd / Nifoam is used as the working electrode for the electrocatalytic oxidation process.
[0064] Comparative Example 2 The catalyst preparation process is the same as in Example 1, except that only Ni nanoparticles are electrodeposited during catalyst preparation to prepare Ni / Nifoam, and the prepared Ni / Nifoam is used as the working electrode for electrocatalytic oxidation.
[0065] Table 1
[0066] As shown in Table 1, the Ni / Pd / Nifoam composite catalyst prepared in Example 1 exhibited excellent electrocatalytic oxidation activity of alcohols (manifested as high current density) and excellent selectivity for organic acid salt products under a bias voltage of 1.0 V vs. RHE. The composite catalysts of Examples 2 and 3, obtained by adjusting the preparation process parameters, showed significantly lower electrocatalytic oxidation current density and organic acid salt product selectivity compared to Example 1. This result indicates that the preparation process parameters play a decisive role in regulating the electrocatalytic performance of the Ni / Pd / Nifoam composite catalyst. Furthermore, the electrocatalytic performance of Comparative Example 1 (Pd / Nifoam single metal catalyst) and Comparative Example 2 (Ni / Nifoam single metal catalyst) was significantly inferior to that of the Ni / Pd / Nifoam composite catalyst, confirming a significant synergistic optimization effect between Ni and Pd nanoparticles in the electrocatalytic reaction process. This synergistic optimization is a key factor in improving the alcohol oxidation activity and product selectivity of the composite catalyst.
[0067] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is impossible to exhaustively list all possible implementations here. All embodiments falling under the scope of the present invention... Obvious variations or modifications derived from the technical solution are still within the scope of protection of this invention.
Claims
1. A method for preparing a composite electrocatalyst, characterized in that, Includes the following steps: Using soluble palladium salt, reducing agent, and first surfactant as raw materials, and foam metal as substrate material, Pd nanoparticles are loaded onto foam metal using a solvothermal method in a weakly acidic environment, denoted as Pd / foam metal. Using Pd / foam metal as the working electrode substrate, Ni nanoparticles were deposited in situ on the surface of Pd / foam metal by electrodeposition under the action of supporting electrolyte, soluble nickel salt and second surfactant. This is referred to as Ni / Pd / foam metal.
2. The preparation method according to claim 1, characterized in that, The soluble palladium salt is selected from one or more of PdCl2, Pd(NO)2, Na2PdCl4, and Pd(NH3)4(NO3)2; The reducing agent is selected from one or more of ascorbic acid, ethylene glycol, and formaldehyde; The first surfactant is selected from hexadecyltrimethylammonium bromide and / or sodium dodecyl sulfate; The foam metal is selected from one or more of foam nickel, foam cobalt, foam iron, and foam copper; Preferably, the mass ratio of the soluble palladium salt to the reducing agent is 1:1 to 1:10; Preferably, the mass ratio of the soluble palladium salt to the first surfactant is 1:1 to 1:5; Preferably, the mass ratio of the soluble palladium salt to the foam metal is 1:10-1:
40.
3. The preparation method according to claim 1, characterized in that, The reaction temperature of the solvothermal method is 40-100°C. o C, reaction time is 0.5-2h.
4. The preparation method according to claim 1, characterized in that, The soluble nickel salt is selected from one or more of NiCl2, Ni(NO3)2, NiSO4, and NiBr2; The supporting electrolyte is selected from NaCl and / or Na2SO4; The second surfactant is selected from polyvinylpyrrolidone and / or hexadecyltrimethylammonium bromide; Preferably, the mass ratio of the soluble nickel salt to the second surfactant is 1:1 to 1:5; Preferably, the mass ratio of the soluble nickel salt to Pd / foam metal is 1:10-1:
40.
5. The preparation method according to claim 1, characterized in that, The electrodeposition process employs a constant voltage mode, with the electrode potential remaining constant between -0.3 and -0.6 V vs. RHE, and the electrodeposition time lasting 10-60 min.
6. A composite electrocatalyst, characterized in that, It is prepared by the preparation method described in any one of claims 1-5.
7. The composite electrocatalyst according to claim 6, characterized in that, The loading of Pd nanoparticles on metal foam was 1-10 mg / cm³. 2 ; The loading of Ni nanoparticles on the Pd / foam metal surface is 0.5-5 mg / cm³. 2 ; Preferably, the atomic ratio of Pd to Ni in the composite electrocatalyst is 1:0.4-1:
4.
8. The application of the composite electrocatalyst of claim 6 or 7 in the electrocatalytic oxidation of alcohols to prepare organic acid salts.
9. An electrolytic cell system for the electrocatalytic oxidation of alcohols to prepare organic acid salts, characterized in that, Including the composite electrocatalyst of claim 6 or 7 and the alkaline electrolyte containing alcohol compounds; Preferably, the alcohol compound is selected from one of methanol, ethanol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, glycerol, 1,3-butanediol, and 1,4-butanediol; The organic acid salt is formate, acetate, glycolate, 2-hydroxypropionate, 3-hydroxypropionate, 2,3-dihydroxypropionate, 3-hydroxybutyrate, or 4-hydroxybutyrate.
10. A method for preparing organic acid salts by electrocatalytic oxidation of alcohols, characterized in that, Includes the following steps: A three-electrode electrolytic cell is assembled with a working electrode, a counter electrode, a reference electrode, and an alkaline electrolyte containing alcohols. An electrocatalytic reaction is carried out by applying voltage, and the alcohols are oxidized at the working electrode to generate the corresponding organic acid salts. The working electrode comprises the composite electrocatalyst of claim 6 or 7.