Foamed nickel-based heterostructure electro-catalytic material as well as preparation method and application thereof
A two-step hydrothermal method was used to prepare heterogeneous nickel-based electrocatalytic materials on nickel foam substrates, which solved the problems of poor selectivity and severe oxygen evolution reaction of nickel-based catalysts under strong alkaline conditions, and achieved efficient conversion of 5-HMF to 2,5-FDCA and improved stability.
Patent Information
- Application Number
- CN202512037712.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-03-20
AI Technical Summary
In existing technologies, nickel-based catalysts exhibit poor selectivity and severe oxygen evolution reaction when used for the electrochemical oxidation of 5-HMF under strong alkaline conditions, making it difficult to achieve efficient conversion and stability. The existing composite structure preparation process is complex and difficult to optimize.
Using thiourea, cobalt sulfate, sodium hypophosphite, and ammonium fluoride as reactants, a heterostructured nickel-based electrocatalytic material was prepared on a nickel foam substrate via a two-step hydrothermal method. The nucleation and growth process of CoP was regulated to construct an open nanostructure.
The preparation process was simplified, the number of catalytic active sites was increased, and the electrocatalytic selectivity was improved. High conversion efficiency and high product yield were achieved at low reaction potentials, and good structural stability and electrochemical durability were demonstrated.
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Figure CN121700437A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrochemical catalysis technology, specifically to a foamed nickel-based heterostructure electrocatalytic material, its preparation method, and its application. Background Technology
[0002] With the increasing depletion of fossil fuels and the escalating environmental problems, developing sustainable biomass resources as alternatives to fossil fuels has become an important research direction. Among these, 5-hydroxymethylfurfural (5-HMF), an important biomass platform molecule derived from cellulose and hemicellulose, can be further oxidized to 2,5-furandicarboxylic acid (2,5-FDCA). 2,5-FDCA is a key monomer for the preparation of bio-based polymers such as polyfurandicarboxylate (PEF), and has broad application prospects in bioplastics, polyesters, and polyurethanes, and is considered an important alternative to traditional petroleum-based polyethylene terephthalate (PET).
[0003] Currently, the conversion of 5-HMF to 2,5-FDCA mainly relies on chemical oxidation methods. These methods typically require high-temperature, high-pressure air or pure oxygen conditions, which are not only energy-intensive and demanding, but also pose safety risks and environmental burdens. In contrast, the electrocatalytic oxidation of 5-HMF can be carried out under ambient temperature and pressure conditions, offering advantages such as mild reaction conditions, high controllability, and environmental friendliness, providing a sustainable technological path for the green preparation of 2,5-FDCA.
[0004] In existing research, noble metal-based catalysts (such as Au, Pt, and Pd) have been shown to have high activity for the electrochemical oxidation of 5-HMF, but their high cost and limited resource reserves severely restrict their large-scale application. In contrast, nickel-based transition metal catalysts are considered ideal candidates for the electrocatalytic oxidation of 5-HMF to 2,5-FDCA due to their abundant reserves, lower cost, and favorable metal-oxygen bond interactions conferred by their 3d orbital electronic structure. However, the electrochemical oxidation of 5-HMF usually requires a strongly alkaline electrolyte. Although a strongly alkaline environment can promote reaction kinetics, it also significantly exacerbates the oxygen evolution reaction, thereby reducing the selectivity for the oxidation of 5-HMF. Therefore, how to improve the selectivity of nickel-based catalysts for 5-HMF and suppress the oxygen evolution side reaction under strongly alkaline conditions remains a key technical problem that urgently needs to be solved.
[0005] To improve the electrochemical performance of nickel-based materials, existing technologies have attempted to modify nickel foam substrates by constructing composite or heterostructures. However, most existing methods involve complex processes, cumbersome steps, and demanding reaction conditions, making it difficult to achieve precise structural control and large-scale preparation. Furthermore, their structural designs are primarily geared towards energy storage device applications and have not optimized for the competitive relationship between 5-HMF and the oxygen evolution reaction during electrocatalytic oxidation in strongly alkaline environments. Consequently, it is difficult to achieve a synergistic improvement in high selectivity and high stability in biomass platform molecular electroconversion. Summary of the Invention
[0006] To address the aforementioned technical problems, this invention provides a nickel-based foamed heterostructure electrocatalytic material and its preparation method, aiming to obtain an electrocatalytic material with a simple preparation method and good structural stability and electrochemical performance.
[0007] To achieve the above objectives, the technical solution provided by the present invention is as follows:
[0008] A nickel foam-based heterostructure electrocatalytic material is prepared on a nickel foam substrate using thiourea, cobalt sulfate, sodium hypophosphite, and ammonium fluoride as reactants via a two-step hydrothermal method.
[0009] A method for preparing the above-mentioned foamed nickel-based heterostructure electrocatalytic material includes the following steps:
[0010] (1) After cleaning the nickel foam to remove surface impurities, it is dried;
[0011] (2) Thiourea ( Add the solution to the solvent and mix thoroughly. Place the resulting solution and the dried nickel foam obtained in step (1) into a reaction vessel for the first hydrothermal reaction. After the reaction is completed, allow it to cool naturally. Wash and dry the resulting sample to obtain the final product. ;
[0012] (3) Cobalt sulfate ( Sodium hypophosphite ( ) and ammonium fluoride ( Add the solution to the solvent and mix thoroughly. Then, combine the resulting mixture with the solution obtained in step (2). The samples were placed together in a reaction vessel for a second hydrothermal reaction. After the reaction, the samples were allowed to cool naturally, and then washed and dried to obtain the final product. That is, the foamed nickel-based heterostructure electrocatalytic material; cobalt sulfate is the sulfur source, and the foamed nickel participates in the reaction as a nickel source during the hydrothermal reaction; Used to regulate the nucleation and growth process of CoP.
[0013] Preferably, the nickel foam in step (1) is a sheet structure, and its size can be determined according to actual needs; the nickel foam is ultrasonically cleaned for 20 minutes in 3M hydrochloric acid solution, acetone, deionized water and anhydrous ethanol respectively to remove surface impurities, and then vacuum dried for later use.
[0014] Preferably, the solvent in steps (2) and (3) is any one of deionized water, distilled water or ultrapure water.
[0015] Preferably, the reaction temperature of the first hydrothermal reaction in step (2) is 120~180℃, and the reaction time is 4~8h.
[0016] Preferably, in step (3), cobalt sulfate ( Sodium hypophosphite ( ), ammonium fluoride ( The molar ratio of the three substances is 1:10:3~6.5.
[0017] Preferably, the reaction temperature of the second hydrothermal reaction in step (3) is 140~180℃ and the reaction time is 4~8h.
[0018] Preferably, the washing and drying process described in steps (2) and (3) involves washing with deionized water and anhydrous ethanol until the cleaning solution is neutral, then vacuum drying at room temperature for 2 hours, and then vacuum drying at 60°C for 8 hours.
[0019] In another aspect, the present invention provides the application of the foamed nickel-based heterostructure electrocatalytic material as described above in the electrooxidation of 5-hydroxymethylfurfural to prepare 2,5-furandicarboxylic acid.
[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0021] (1) The present invention can prepare nickel-based electrocatalytic materials with heterostructures through only two hydrothermal reactions. The preparation process is simple and the reaction conditions are mild, which is conducive to the uniform growth of electrocatalytic materials on nickel foam substrates.
[0022] (2) By introducing By regulating the nucleation and growth process of CoP, CoP nanosheets with open nanostructures can be obtained, thereby increasing the number of active sites and improving the activity of 5-HMF electrocatalytic oxidation reaction.
[0023] (3) By constructing The heterostructure enables effective control of the electronic structure of nickel foam-based heterostructure electrocatalytic materials, providing a feasible strategy for improving their electrocatalytic selectivity. Thanks to the charge transfer effect at the heterostructure interface, the nickel foam-based heterostructure electrocatalytic material of this invention exhibits good structural stability and electrochemical durability.
[0024] (4) The two-step hydrothermal method provided by the present invention for preparing Electrocatalytic materials effectively improve the selectivity of nickel foam-based heterostructure electrocatalytic materials in the electrochemical oxidation process of 5-HMF, and achieve high conversion efficiency, product yield and Faraday efficiency at a low reaction potential. Attached Figure Description
[0025] Figure 1 The product obtained in Embodiment 1 of the present invention Scanning transmission electron microscopy (SEM) images and mapping diagrams of electrocatalytic materials; where a, b, and c represent different scales. The SEM images are shown, where d, e, f, and g are the mapping images of Co, P, Ni, and S elements, respectively.
[0026] Figure 2 The product obtained in Embodiment 1 of the present invention and XRD pattern of electrocatalytic material.
[0027] Figure 3 The NF dried and ready for use in step (1) of Example 1 of this invention, and the NF obtained in step (2) of Example 1. The result obtained in step (3) of Example 1 Linear sweep voltammetry (LSV) test curve of the CoP / NF prepared in Example 8 in the test example.
[0028] Figure 4 The NF dried and ready for use in step (1) of Embodiment 1 of the present invention, and the NF obtained in step (2) The product obtained in step (3) Tafel slope diagram of the CoP / NF electrocatalytic material prepared in Example 8.
[0029] Figure 5 The result obtained in step (2) of Embodiment 1 of the present invention The product obtained in step (3) ECSA diagram of the CoP / NF electrocatalytic material prepared in Example 8.
[0030] Figure 6 The product obtained in Embodiment 1 of the present invention In the test example, the electrocatalytic material was analyzed by high-performance liquid chromatography (HPLC) at different charge levels, and the amount of product was obtained by HOLC.
[0031] Figure 7 The product obtained in Embodiment 1 of the present invention The HMF conversion, FDCA yield, and Faraday efficiency of the electrocatalytic material obtained by five cycles at a constant potential of 1.36V in the test example are plotted. Detailed Implementation
[0032] The following detailed description, in conjunction with the accompanying drawings, outlines specific embodiments. However, it should be understood that the scope of protection of this invention is not limited to these specific embodiments. Unless otherwise specified, all raw materials and reagents used in the examples are commercially available.
[0033] Example 1
[0034] A method for preparing a foamed nickel-based heterostructure electrocatalytic material, comprising the following steps:
[0035] (1) A piece of nickel foam (NF) with a size of 2cm×1cm×2mm was ultrasonically cleaned in acetone, 3M hydrochloric acid solution, deionized water and anhydrous ethanol for 20min to remove surface impurities, and then vacuum dried for later use.
[0036] (2) Take 0.19g of Dissolve the sample in 80 mL of deionized water and mix thoroughly. Place the resulting solution and the dried nickel foam from step (1) into a 100 mL reactor and perform the first hydrothermal reaction at 180 °C for 6 h. After the reaction is complete, allow the autoclave to cool naturally, remove the sample, and wash the sample with deionized water until the washing solution is neutral. Then wash it once with anhydrous ethanol, and then vacuum dry it at room temperature for 2 hours, and then vacuum dry it at 60 °C for 8 hours to obtain the final product. Regarding the income XRD tests were performed with scanning angles ranging from 10° to 80°, and the results are as follows. Figure 2 As shown;
[0037] (3) Take 0.4216g of 1.6066g and 0.15g Dissolve in 80 mL of deionized water and mix thoroughly. Combine the resulting mixed solution with the solution obtained in step (2). Both were placed in a 100 mL autoclave and subjected to a second hydrothermal reaction at 150 °C for 6 hours. After the reaction, the autoclave was allowed to cool naturally, and the sample was removed. The sample was first washed with deionized water until the washing solution was neutral, and then washed once with anhydrous ethanol. It was then dried at room temperature for 2 hours, and then dried at 60 °C for 8 hours to obtain the final product. This refers to a nickel-foamed heterostructure electrocatalytic material. The obtained... Scanning transmission electron microscopy (STEM), mapping scans, and XRD tests were performed at scanning angles ranging from 10° to 80°, yielding results such as... Figure 1 , Figure 2 The diagram shows the structures; a, b, and c represent different scales. The SEM images show that d, e, f, and g are the elemental mappings for Co, P, Ni, and S, respectively. This can be seen from... Figure 1 As can be seen from this embodiment, the electrocatalytic material obtained... It exhibits a flower-like structure, which increases the specific surface area of the catalyst. From Figure 2 It can be seen that the result obtained in step (2) As it is a crystal, the second hydrothermal step has no effect on its crystal morphology, which shows that... Electrocatalytic material CoP and They combine in the form of heterojunctions.
[0038] Example 2
[0039] A method for preparing a foamed nickel-based heterostructure electrocatalytic material, comprising the following steps:
[0040] In step (2), the first hydrothermal reaction is carried out at 160°C for 5 hours. The remaining operations and steps are the same as in Example 1, yielding... This refers to nickel foam-based heterostructure electrocatalytic materials.
[0041] Example 3
[0042] A method for preparing a foamed nickel-based heterostructure electrocatalytic material, comprising the following steps:
[0043] In step (2), the first hydrothermal reaction is carried out at 150°C for 4 hours. The remaining operations and steps are the same as in Example 1, yielding... This refers to nickel foam-based heterostructure electrocatalytic materials.
[0044] Example 4
[0045] A method for preparing a foamed nickel-based heterostructure electrocatalytic material, comprising the following steps:
[0046] In step (2), the first hydrothermal reaction is carried out at 160°C for 5 hours. The remaining operations and steps are the same as in Example 1, yielding... This refers to nickel foam-based heterostructure electrocatalytic materials.
[0047] Example 5
[0048] A method for preparing a foamed nickel-based heterostructure electrocatalytic material, comprising the following steps:
[0049] In step (3), 0.4216g of 1.6066g and 0.3g Dissolve in 80 mL of deionized water and mix thoroughly. Combine the resulting mixed solution with the solution obtained in step (2). Both were placed in a 100 mL reactor and subjected to a second hydrothermal reaction at 180 °C for 4 hours. The remaining operations and steps were the same as in Example 1, yielding... This refers to nickel foam-based heterostructure electrocatalytic materials.
[0050] Example 6
[0051] A method for preparing a foamed nickel-based heterostructure electrocatalytic material, comprising the following steps:
[0052] In step (3), a second hydrothermal reaction is carried out at 180°C for 5 hours. The remaining operations and steps are the same as in Example 1, yielding... This refers to nickel foam-based heterostructure electrocatalytic materials.
[0053] Example 7
[0054] A method for preparing a foamed nickel-based heterostructure electrocatalytic material, comprising the following steps:
[0055] In step (3), a second hydrothermal reaction is carried out at 180°C for 6 hours. The remaining operations and steps are the same as in Example 1, yielding... This refers to nickel foam-based heterostructure electrocatalytic materials.
[0056] Example 8
[0057] CoP / NF was prepared by a one-step hydrothermal synthesis: a piece of 2cm×1cm×2mm nickel foam was ultrasonically cleaned in acetone, 3M HCl solution, deionized water and anhydrous ethanol for 20 min and then vacuum dried for later use.
[0058] 0.4216g 1.6066g and 0.15g Dissolve in 80 mL of deionized water and stir until homogeneous. Then, transfer the homogeneous solution together with the nickel foam to a 100 mL autoclave and maintain at 150 °C for 6 h. After the autoclave cools naturally, remove the sample and wash it with deionized water until the washing solution is neutral, then wash it once with anhydrous ethanol, then vacuum dry at room temperature for 2 h, and then vacuum dry at 60 °C for 8 h to obtain CoP / NF.
[0059] Test case
[0060] The electrochemical performance tests of this invention were all performed using a Gmary electrochemical workstation with a three-electrode system: the NF (comparative sample) dried and ready for use in step (1) of Example 1 and the sample obtained in step (2) of Example 1 were used. (Comparative sample), obtained from step (3) of Example 1 The CoP / NF (comparative sample) prepared in Example 8 was used as the working electrode, a platinum sheet as the counter electrode, and a saturated mercury / mercury oxide electrode (Hg / HgO) as the reference electrode. All electrochemical tests were performed in an H-type electrolytic cell with an effective volume of 30 mL, with the anode and cathode chambers separated by a proton exchange membrane Nafion 117. 30 mL of electrolyte was added to each chamber, with 1 mM MKOH solution used as the electrolyte in the cathode chamber and a suitable electrolyte selected for the anode chamber based on the specific test. In the electrocatalytic oxidation test of 5-hydroxymethylfurfural (5-HMF), a mixed solution of 10 mM 5-HMF and 1 mM MKOH was used as the electrolyte in the anode chamber; in the oxygen evolution reaction test, 1 mM MKOH solution was used as the electrolyte in the anode chamber.
[0061] All potentials obtained during the testing process were converted to potentials relative to the reversible hydrogen electrode (RHE) using the following formula:
[0062]
[0063] Linear sweep voltammetry (LSV) was performed at a scan rate of 5 mV·s⁻¹ to compare the electrochemical performance of different electrocatalytic materials in the electrocatalytic oxidation of 5-hydroxymethylfurfural. The results are as follows: Figure 3 As shown. Figure 3 The obtained LSV plot was fitted with Tafel to obtain Figure 4 Compared with the control sample, the present invention The catalytic electrode exhibits a smaller Tafel slope, indicating faster reaction kinetics in the electrocatalytic oxidation of 5-hydroxymethylfurfural, which is beneficial for reducing the reaction overpotential and improving the overall reaction efficiency. CV tests were performed on three samples at scan rates of 20 mV / s, 40 mV / s, 60 mV / s, 80 mV / s, and 100 mV / s. The average current difference at the intermediate potential was calculated as ECSA = Cdl / Cs, where Cdl = (jmax - jmin / v) / 2, and Cs is the specific capacitance per unit real surface area, commonly assumed to be 0.040 mF·cm⁻². Figure 5 The double-layer capacitance of the electrode was determined by performing cyclic voltammetry tests within the non-Radidatic range, and the electrochemically active specific surface area was estimated accordingly. The results show that this invention… Electrodes have a larger electrochemically active surface area, which can provide more electrochemically active sites to participate in the reaction.
[0064] Electrolysis was performed at a constant potential of 1.36 V (vs RHE). 20 μL of electrolyte samples were collected after transferring charges of 20 C, 40 C, 60 C, 80 C, 100 C, and 120 C, and diluted to 1 mL with ultrapure water. Quantitative analysis of the reactants and products was then performed at room temperature using a PerkinElmer LC300 high-performance liquid chromatograph. Chromatographic separation was performed using a C18 column (250 × 4.6 mm, 5 μm) with a UV detector. Mobile phase A was 5 mM ammonium formate aqueous solution, and mobile phase B was methanol, with a volume ratio of mobile phase A to mobile phase B of 3:7. The flow rate was set to 0.6 mL·min⁻¹. Detection was performed at a wavelength of 265 nm. Figure 6 This indicates that in Under catalytic conditions, the electro-oxidation reaction of HMF mainly follows the reaction pathway with HMFCA as the key intermediate, while the competitive reaction pathway mediated by DFF is significantly inhibited.
[0065] A constant potential electrolysis experiment was conducted for five cycles at a constant potential of 1.36V (vsRHE). The conversion rate of HMF, the yield of FDCA, and the Faraday efficiency were calculated. Figure 7 A quantitative amount was taken during the electrolysis process. The conversion rate of 5-HMF, the yield of 2,5-furandicarboxylic acid (2,5-FDCA), and the Faraday efficiency were calculated according to the following formulas:
[0066] 5-HMF conversion rate (%) = [n(5-HMF consumption) / n(initial 5-HMF)] × 100%
[0067] 2,5-FDCA yield (%) = [n(2,5-FDCA generated) / n(5-HMF initial)] × 100%
[0068] Faraday efficiency (%) = [n(2,5-FDCA generation) / (Q / (6×F))]×100%
[0069] Where F is the Faraday constant (96485 C·mol⁻¹), n is the number of moles of the corresponding substance calculated based on the high performance liquid chromatography test results, and Q is the total charge passing through during the electrolysis process. This indicates that CoP / Ni3S2 / NF simultaneously achieves a HMF conversion rate of nearly 100%, an FDCA yield of 98%, and a stable Faraday efficiency of 99%, demonstrating that this heterostructure electrode can achieve synergistic optimization in HMFOR in terms of reactivity, pathway selectivity, and electron utilization efficiency.
[0070] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.
Claims
1. A foamed nickel-based heterostructure electrocatalytic material, characterized in that: Nickel-based electrocatalytic materials with heterogeneous structures were prepared on a nickel foam substrate using thiourea, cobalt sulfate, sodium hypophosphite, and ammonium fluoride as reactants via a two-step hydrothermal method.
2. A method for preparing the foamed nickel-based heterostructure electrocatalytic material as described in claim 1, characterized in that, The operation includes the following steps: (1) Clean and dry the nickel foam; (2) Thiourea is added to the solvent and mixed evenly. The resulting solution and the dried nickel foam obtained in step (1) are placed in a reaction vessel for the first hydrothermal reaction. After the reaction is completed, the mixture is cooled, and the resulting sample is washed and dried to obtain the final product. ; (3) Add cobalt sulfate, sodium hypophosphite and ammonium fluoride to the solvent and mix well. Then, mix the resulting solution with the solution obtained in step (2). The samples were placed together in a reaction vessel for a second hydrothermal reaction. After the reaction was completed, the mixture was cooled, and the resulting sample was washed and dried to obtain... That is, the foamed nickel-based heterostructure electrocatalytic material.
3. The preparation method of the nickel-based heterostructure electrocatalytic material according to claim 2, characterized in that: The nickel foam described in step (1) has a sheet-like structure; the nickel foam is ultrasonically cleaned for 20 minutes in 3M hydrochloric acid solution, acetone, water and ethanol respectively, and then vacuum dried for later use.
4. The preparation method of the nickel-based heterostructure electrocatalytic material according to claim 2, characterized in that: The solvent mentioned in steps (2) and (3) is any one of deionized water, distilled water or ultrapure water.
5. The method for preparing the nickel-based heterostructure electrocatalytic material according to claim 2, characterized in that: In step (2), the reaction temperature of the first hydrothermal reaction is 120~180℃, and the reaction time is 4~8h.
6. The method for preparing the nickel-based heterostructure electrocatalytic material according to claim 2, characterized in that: In step (3), the molar ratio of cobalt sulfate, sodium hypophosphite, and ammonium fluoride is 1:10:3~6.
5.
7. The method for preparing the nickel-based heterostructure electrocatalytic material according to claim 2, characterized in that: In step (3), the reaction temperature of the second hydrothermal reaction is 140~180℃ and the reaction time is 4~8h.
8. The method for preparing the nickel-based heterostructure electrocatalytic material according to claim 2, characterized in that: The washing and drying process described in steps (2) and (3) involves washing with water and ethanol until the cleaning solution is neutral, then vacuum drying at room temperature for 2 hours, and then vacuum drying at 60°C for 8 hours.
9. The application of the foamed nickel-based heterostructure electrocatalyst material as described in claim 1 or the foamed nickel-based heterostructure electrocatalyst material prepared by any method of claims 2-8 in the electrooxidation of 5-hydroxymethylfurfural to prepare 2,5-furandicarboxylic acid.