A method for synthesizing a bifunctional MOF catalyst based on waste pollutants in one pot and application

Abstract

The present application relates to the technical field of electrocatalysis, and in particular to a method for synthesizing a bifunctional MOF electrocatalyst based on waste pollutants by one-pot method and application. The preparation raw material uses toxic waste containing PAEs and additives to replace the traditional MOF ligand. The catalyst prepared by this method has the same catalytic performance as the catalyst prepared from commercial raw materials, and is superior to the traditional commercial catalyst in the fields of oxygen evolution (OER) and hydrogen evolution (HER). The catalyst preparation process has the advantages of simple and efficient process, greatly shortened synthesis period, reduced operation complexity, low energy consumption, green and sustainable, strong structure controllability, safe operation and the like. The present application provides a green and feasible path for the in-situ conversion of toxic organic pollutants (such as DBP) into high-value functional materials.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalysis technology, and relates to a method for treating pollutants, a method for synthesizing and preparing novel MOF materials, and their applications. Specifically, it relates to a method and its application for synthesizing bifunctional MOF electrocatalysts based on a one-pot method using waste pollutants. Background Technology

[0002] Phthalate esters (PAEs) are widespread environmental pollutants, especially as plasticizers added to EVA adhesives, PET plastics, and rubber. For example, during the dismantling or disposal of photovoltaic modules, if proper handling is lacking, EVA films are prone to aging and degradation, leading to the release of large amounts of physically mixed PAEs into the soil and water environment. Currently, photovoltaic module dismantling primarily uses physical methods, such as crushing and recycling. Valuable components like aluminum, silver, and copper, as well as silicon and glass, are directly reused. However, waste dust and liquids such as DBP are classified as waste and not separately recycled for value. The released PAEs currently have no value in being recycled and reused in EVA, primarily due to the high cost. Because PAEs are highly lipid-soluble, difficult to biodegrade, and have strong endocrine disrupting properties, they can accumulate persistently in ecosystems and bioaccumulate through the food chain, ultimately causing reproductive system damage, developmental abnormalities, and even carcinogenic risks, posing a threat to ecological security and public health. Summary of the Invention

[0003] One of the objectives of this invention is to provide a method for preparing MOF materials based on PAEs in order to overcome the defects of the existing technology. This method uses a green hydrolysis process to degrade and upgrade toxic PAEs, specifically converting PAEs into functional organic ligands to synthesize high-performance metal-organic framework catalytic electrodes, thereby reducing environmental pollution.

[0004] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0005] A method for one-pot synthesis of bifunctional MOF electrocatalysts based on waste pollutants.

[0006] Weigh PAE waste, nickel salt and / or cobalt salt, PVP, a mixed solvent of ethanol, deionized water and DMF in a volume ratio of 1:1:1, and trivalent iron salt, mix thoroughly, and then transfer to a polytetrafluoroethylene-lined reactor. React at 100~200℃ for 24~60 h to obtain Fe3O4-doped MOF material Fe3O4-Ni(Co)-MOF with Ni and / or Co nodes.

[0007] The molar ratio of metal salt to PAEs in PAEs waste is 1~3:1;

[0008] The Fe:Ni molar ratio is 1~4:1~4 or the Fe:Co molar ratio is 1~3:1~4.

[0009] The MOF material obtained by the above method is a solid substance obtained by mixing metal salts (such as Co salts, Ni salts, CoNi salts, etc.) with PAEs and then heating and reacting them in an autoclave.

[0010] Furthermore, PAEs are used as plasticizers in PAE waste;

[0011] Alternatively, PAEs waste refers to the waste from the dismantling of photovoltaic modules containing PAEs.

[0012] Furthermore, the PAEs are at least one of di(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), diisobutyl phthalate (DIBP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), dioctyl phthalate (DNOP), diisooctyl phthalate (DIOP), dimethyl phthalate (DMP), diethyl phthalate (DEP), dipropyl phthalate (DPrP), dipentyl phthalate (DPP), and dinonyl phthalate (DNP).

[0013] Furthermore, the trivalent ferric salt is at least one of ferric chloride hexahydrate, ferric sulfate nonahydrate, and ferric nitrate nonahydrate.

[0014] Furthermore, the process includes the following steps: nickel foam (NF) is also placed in a high-pressure reactor, where a metal-organic framework (MOF) grows on its surface. This strategy employs a one-pot synthesis of metal-organic framework composites supported on nickel foam (NF), producing a highly efficient electrocatalyst for total water splitting. This work proposes an innovative strategy for converting toxic plastic pollutants into valuable substances, thereby promoting the cross-integration of environmental remediation and clean energy technologies.

[0015] The second objective of this invention is to design and prepare a highly efficient OER / HER bifunctional catalyst for water electrolysis, based on the detoxification of PAEs, so as to achieve low energy consumption and green sustainable development of water electrolysis.

[0016] In summary, the present invention also has the following beneficial effects:

[0017] This invention discloses a method for preparing novel MOF materials using a one-pot process with toxic pollutants, as well as a method for preparing and applying an electrocatalytic working electrode. It realizes the concept of "turning waste into treasure"—that is, generating MOF (metal-organic framework) materials by reacting the low-toxicity phthalic acid obtained from decomposition with metal salts. The catalyst Fe3O4-Ni(Co)-MOF / NF provided by this invention exhibits excellent electrochemical catalytic performance, offering new ideas for the preparation of OER and HER catalysts, and is of great significance for promoting sustainable development. Attached Figure Description

[0018] Figure 1 Here is a simplified flowchart (A) and mechanism diagram of the preparation of the catalyst in this invention.

[0019] Figure 2 The images show the characterization of Ni-MOFs. A is the ESM image of the purchased phthalic acid ligand; B is the scanning electron microscope (SEM) image of the Ni-MOF prepared with phthalic acid in Example 5-1 (without PVP morphology modification); C is the SEM image of the Ni-MOF prepared with phthalic acid in Example 5-2 (with PVP added); D is the TEM image of the Ni-MOF (1,2-BDC) in Example 5-1 (with PVP added); E is the SEM image of the Ni-MOF prepared with PAEs in Example 5-3 (without PVP morphology modification); F is the SEM image of the Ni-MOF prepared with PAEs in Example 5-4 (with PVP added); G is the TEM image of the Ni-MOF prepared with PAEs in Example 5-4 (with PVP added); H and I are the mapping elemental distribution and EDS curve of the Ni-MOF (PAEs) in Example 5-4.

[0020] Figure 3 These are SEM images of Fe3O4-Ni-MOF with different metal (Fe:Ni) ratios, A ~ E: 1:4 (Experiment 7-1); 2:3 (Experiment 7-2); 1:1 (Example); 3:2 (Experiment 7-3); 4:1 (Experiment 7-4).

[0021] Figure 4 These are morphology diagrams of different catalyst materials grown on NF, A ~ G: NF; Ni-MOF / NF (Experimental Example 5-4); Fe3O4-Ni-MOF / NF (Example); Local magnification of NF; Local magnification of Ni-MOF / NF; Local magnification of Fe3O4-Ni-MOF / NF; Elemental distribution diagram of Fe3O4-Ni-MOF / NF (Example).

[0022] Figure 5These are SEM images of Co-MOF (Experimental Example 4-12) and Co-MOF / NF (Experimental Example 4-12).

[0023] Figure 6 These are SEM images of Fe3O4-Co-MOF with different metal (Co:Fe) ratios, A ~ D: 3:2 (Example); NF growth image of 3:2 (Example); 1:1 (Experimental Example 7-5); 2:3 (Experimental Example 7-7).

[0024] Figure 7 The graphs show the OER and HER performance of different catalyst materials (examples, test examples 5-4, and comparison with commercial catalysts).

[0025] Figure 8 The graphs show the OER and HER performance of Ni catalyst materials with different metal ratios (compared with Examples 7-1, 7-2, 7-3, and 7-4).

[0026] Figure 9 The graphs show the OER and HER performance of Ni catalyst materials with different metal raw materials and ligands (comparison of examples with test examples 8-1, 8-2 and 8-3).

[0027] Figure 10 The OER performance graphs are shown below, where A represents different catalyst materials (Examples and Test Examples 4-12), B represents Co catalyst materials with different ligands (Examples and Test Examples 8-4), and C represents Co catalyst materials with different metal ratios (Examples and Test Examples 7-5, 7-6, 7-7, and 7-8).

[0028] Figure 11 In the example, it is Fe3O4-Ni-MOF / NF (DBP, Ni:Fe=1:1, Fe 3+ OER and HER stability tests.

[0029] Figure 12 In the example, it is Fe3O4-Ni-MOF / NF (DBP, Ni:Fe=1:1, Fe 3+ The water-lysis performance and stability of the product were tested.

[0030] Figure 13 In the example, it is Fe3O4-Ni-MOF / NF (DBP, Ni:Fe=1:1, Fe 3+ Experiments on the OER and HER gas collection devices and Faraday efficiency calculations.

[0031] Figure 14 This is the XRD pattern of the control sample Fe.

[0032] Figure 15 This is the XRD pattern of the control sample Cu.

[0033] Figure 16 This is the XRD pattern of the control sample Zn.

[0034] Figure 17 This is a SEM image of the MOF prepared in Example 4. Detailed Implementation

[0035] To further illustrate the technical means and effects adopted by this invention to achieve its intended purpose, this invention is not limited to the following specific embodiments. Those skilled in the art can implement this invention using various other specific embodiments based on the content disclosed herein. Any modifications or alterations made to the design structure and concept of this invention fall within the protection scope of this invention. It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0036] In some embodiments, a method for synthesizing bifunctional MOF electrocatalysts based on waste pollutants in a one-pot process is provided, comprising the following steps:

[0037] Weigh PAE waste, nickel salt and / or cobalt salt, PVP, a mixed solvent of ethanol, deionized water and DMF in a volume ratio of 1:1:1, and trivalent iron salt, mix thoroughly, and then transfer to a polytetrafluoroethylene-lined reactor. React at 100~200℃ for 24~60 h to obtain Fe3O4-doped MOF material Fe3O4-Ni(Co)-MOF with Ni and / or Co nodes.

[0038] The molar ratio of metal salt to PAEs in PAEs waste is 1~3:1; the Fe:Ni molar ratio is 1~4:1~4 or the Fe:Co molar ratio is 1~3:1~4.

[0039] Specifically, PAEs in PAE waste can be used as plasticizers or as waste from the dismantling of photovoltaic modules containing PAEs.

[0040] The PAEs are at least one of di(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), diisobutyl phthalate (DIBP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), dioctyl phthalate (DNOP), diisooctyl phthalate (DIOP), dimethyl phthalate (DMP), diethyl phthalate (DEP), dipropyl phthalate (DPrP), dipentyl phthalate (DPP), and dinonyl phthalate (DNP). These PAEs, in the above reaction, will hydrolyze to yield 1,2-BDC phthalic acid. The prepared catalyst exhibits the same performance as that obtained by directly adding an equimolar amount of 1,2-BDC.

[0041] More specific embodiments are as follows. For ease of research and comparison, DBP is used to represent PAEs in the following embodiments and test cases, but this does not represent a limitation on PAEs.

[0042] In the examples and experimental cases, the trivalent ferric salt can be any one or more of ferric chloride hexahydrate, ferric sulfate nonahydrate, and ferric nitrate nonahydrate; the specific selection has a negligible impact on the catalyst performance. Furthermore, the amount of PVP added can be 41% to 44% of the total mass of the metal salt.

[0043] In this invention, the electrode material can be any material in the art, such as ITO, FTO, glassy carbon, carbon cloth, nickel foam, etc. The following embodiments use nickel foam as an example.

[0044] Example: A method and application for one-pot synthesis of bifunctional MOF catalysts based on waste pollutants.

[0045] (1) A method for preparing novel electrocatalytic materials Fe3O4-Ni-MOF and Fe3O4-Co-MOF:

[0046] S1. Add 0.347g of iron salt (Fe 3+ ) and 0.25 g nickel salt (or 0.2776 g iron salt and 0.3 g cobalt salt) and 0.859 mmol ligand DBP were dissolved in a mixed solvent (a mixture of ethanol, N,N-dimethylformamide DMF and deionized water in a volume ratio of 1:1:1) Fe:Ni=1:1; Fe:Co=2:3.

[0047] S2. Stir the mixture obtained in step S1 vigorously at room temperature until homogeneous, and add 0.25g PVP.

[0048] S3. Transfer the homogeneous solution obtained in step S2 to a high-pressure reactor lined with polytetrafluoroethylene. The reaction temperature is 180℃, and the reaction time is 60h.

[0049] S4. The catalyst obtained in step S3 was washed with 10 mL of ethanol, 10 mL of DMF and 10 mL of deionized water, and dried at 60 °C overnight. The Fe3O4-Ni-MOF and Fe3O4-Co-MOF powder catalysts were obtained.

[0050] (2) Preparation method of the Fe3O4-Ni-MOF / NF and Fe3O4-Co-MOF / NF electrocatalytic electrodes:

[0051] A1. 0.347g of iron salt (Fe 3+) and 0.25 g of nickel salt (0.2776 g of iron salt and 0.3 g of cobalt salt) and 0.859 mmol of ligand DBP were dissolved in a mixed solvent (a mixture of ethanol, N,N-dimethylformamide DMF and deionized water in a volume ratio of 1:1:1) Fe:Ni=1:1; Fe:Co=2:3.

[0052] A2. Stir the mixture obtained in step A1 vigorously at room temperature until homogeneous, and add 0.25g PVP.

[0053] A3. Transfer the homogeneous solution obtained in step A2 to a high-pressure reactor lined with polytetrafluoroethylene (PTFE), and place nickel foam (NF) on its surface to allow MOF to grow. The reaction temperature is 180°C, and the reaction time is 60 h.

[0054] A4. The catalyst obtained in step A3 is washed with deionized water and dried at 60°C overnight. The monolithic Fe3O4-Ni-MOF / NF and Fe3O4-Co-MOF / NF catalysts are obtained.

[0055] (3) Electrochemical testing methods for OER and HER, the specific steps are as follows:

[0056] B1. Prepare the electrolyte: 1.0 mol KOH solution;

[0057] B2. The working areas of the NF-based catalyst samples Fe3O4-Ni-MOF / NF and Fe3O4-Co-MOF / NF were cut to 0.4cm×0.5cm to serve as the working electrodes for OER and HER, with the Hg / HgO electrode serving as the reference electrode and the platinum sheet electrode serving as the auxiliary electrode.

[0058] B3. Performance curve testing and plotting:

[0059] The working electrode was activated for HER and OER tests by performing cyclic voltammetry scans for 30 cycles within the electrochemical window ranges of -1.5 to -0.8 V and 0 to 1.0 V, respectively, at a scan rate of 0.1 V / s. The working electrode was then placed within the corresponding electrochemical window range, and LSV tests were performed at a scan rate of 0.005 V / s. The average value was taken after three scans, and a comparison chart of LSV performance of different materials was established.

[0060] B4. Construct an H-shaped tank gas collection system and use the water displacement gas collection method to collect O2 and H2 during the OER and HER reactions. Calculate the Faraday efficiency of OER and HER.

[0061] Example 1: Other metal MOF catalysts based on PAEs

[0062] (1) Preparation of Fe-MOF based on PAEs

[0063] Experimental Example 1-1

[0064] 0.135 g of 1,2-BDC and 0.44 g of FeCl3·6H2O were added to 20 mL of DMF without adding deionized water. After thorough stirring, the solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 120 °C for 24 h. After cooling, the solution was washed with DMF and EtOH (ethanol) at 10,000 rpm and dried at 70 °C for 12 h.

[0065] Experimental Examples 1-2

[0066] 0.135 g of 1,2-BDC and 0.44 g of FeCl3·6H2O were added to 20 mL of DMF, followed by 10 mL of H2O. After thorough stirring, the solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 120 °C for 24 h. After cooling, the solution was washed with DMF and EtOH (ethanol) at 10,000 rpm and dried at 70 °C for 12 h.

[0067] Experimental Examples 1-3

[0068] 0.2262 g DBP and 0.44 g FeCl3·6H2O were added to 20 mL DMF, along with 10 mL H2O. After thorough stirring, the solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 120 °C for 24 h. After cooling, the solution was washed with DMF and EtOH (ethanol) at 10000 rpm and dried at 70 °C for 12 h.

[0069] Experimental Examples 1-4

[0070] The ratio of ligand DBP was adjusted to n(Fe):n(ligand) = 4:3, and 0.44 g FeCl3·6H2O was added to 20 mL DMF, along with 10 mL H2O. After thorough stirring, the solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 120 °C for 24 h. After cooling, the solution was washed with DMF and EtOH (ethanol) at 10,000 rpm and dried at 70 °C for 12 h.

[0071] Experimental Examples 1-5

[0072] The ratio of ligand DBP was adjusted to n(Fe):n(ligand) = 4:1, and 0.44 g FeCl3·6H2O was added to 20 mL DMF, along with 10 mL H2O. After thorough stirring, the solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 120 °C for 24 h. After cooling, the solution was washed with DMF and EtOH (ethanol) at 10,000 rpm and dried at 70 °C for 12 h.

[0073] Experimental Examples 1-6

[0074] 0.2262 g DBP and 0.44 g FeCl3·6H2O were thoroughly stirred in 20 mL DMF, followed by the addition of 8 mL H2O and 250 μL of 1 mol / L HCl. The solution was then transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 120 °C for 24 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0075] Experimental Examples 1-7

[0076] 0.2262 g DBP and 0.44 g FeCl3·6H2O were thoroughly stirred in 20 mL DMF, followed by the addition of 8 mL H2O and 500 μL of 1 mol / L HCl. The solution was then transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 120 °C for 24 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0077] Experimental Examples 1-8

[0078] 0.2262 g DBP and 0.44 g FeCl3·6H2O were thoroughly stirred in 20 mL DMF, followed by the addition of 8 mL H2O and 1000 μL of 1 mol / L HCl. The solution was then transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 120 °C for 24 h. After cooling, the solution was washed with DMF and EtOH at 10000 rpm and dried at 70 °C for 12 h.

[0079] Experimental Examples 1-9

[0080] 0.2262 g DBP and 0.44 g FeCl3·6H2O were thoroughly stirred in 20 mL DMF, followed by the addition of 8 mL H2O and 1500 μL of 1 mol / L HCl. The solution was then transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 120 °C for 24 h. After cooling, the solution was washed with DMF and EtOH at 10000 rpm and dried at 70 °C for 12 h.

[0081] Experimental Examples 1-10

[0082] 0.135 g of 1,2-BDC and 0.44 g of FeCl3·6H2O were thoroughly stirred in 20 mL of DMF, followed by the addition of 10 mL of H2O, 10 mL of EtOH, and 10 mL of deionized water. The solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 60 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0083] Experimental Example 1-11

[0084] 0.135 g of 1,2-BDC and 0.44 g of FeCl3·6H2O were thoroughly stirred in 20 mL of DMF, followed by the addition of 10 mL of H2O, 10 mL of EtOH, and 10 mL of deionized water. The solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 48 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0085] Experimental Examples 1-12

[0086] 0.135 g of 1,2-BDC and 0.44 g of FeCl3·6H2O were thoroughly stirred in 20 mL of DMF, followed by the addition of 10 mL of H2O, 10 mL of EtOH, and 10 mL of deionized water. The solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 24 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0087] Experimental Examples 1-13

[0088] 0.2262 g of DBP and 0.44 g of FeCl3·6H2O were thoroughly stirred in 20 mL of DMF, followed by the addition of 10 mL of H2O, 10 mL of EtOH, and 10 mL of deionized water. The solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 60 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0089] Experimental Examples 1-14

[0090] 0.2262 g of DBP and 0.44 g of FeCl3·6H2O were thoroughly stirred in 20 mL of DMF, followed by the addition of 10 mL of H2O, 10 mL of EtOH, and 10 mL of deionized water. The solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 48 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0091] Experimental Examples 1-15

[0092] 0.2262 g of DBP and 0.44 g of FeCl3·6H2O were thoroughly stirred in 20 mL of DMF, followed by the addition of 10 mL of H2O, 10 mL of EtOH, and 10 mL of deionized water. The solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 24 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0093] (2) Preparation of Cu-MOF based on PAEs

[0094] Experimental Example 2-1

[0095] 0.3323 g (0.2 M) 1,2-BDC and 1.0229 g (0.3 M) CuCl2·2H2O were dissolved in 20 mL of H2O (solution pH=4). After thorough stirring, the solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 24 h. After cooling, the solution was washed with H2O at 10,000 rpm and dried at 70 °C for 12 h.

[0096] Experimental Example 2-2

[0097] 0.5567 g (0.2 M) DBP and 1.0229 g (0.3 M) CuCl2·2H2O were dissolved in 20 mL of H2O (solution pH=4). After thorough stirring, the solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 24 h. After cooling, the solution was washed with H2O at 10000 rpm and dried at 70 °C for 12 h.

[0098] Experimental Examples 2-3

[0099] 0.5567 g (0.2 M) DBP and 1.0229 g (0.3 M) CuCl2·2H2O were dissolved in 20 mL of H2O (solution pH=4), and the pH was adjusted to 3. After thorough stirring, the solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 24 h. After cooling, the solution was washed with H2O at 10,000 rpm and dried at 70 °C for 12 h.

[0100] Experimental Examples 2-4

[0101] 0.5567 g (0.2 M) DBP and 1.0229 g (0.3 M) CuCl2·2H2O were dissolved in 20 mL of H2O (solution pH=4), and the pH was adjusted to 2. After thorough stirring, the solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 24 h. After cooling, the solution was washed with H2O at 10000 rpm and dried at 70 °C for 12 h.

[0102] (3) Preparation of Zn-MOF based on PAEs

[0103] Experimental Example 3-1

[0104] 0.756 g of 1,2-BDC ligand and 1 g of zinc acetate dihydrate were dissolved in 30 mL of DMF, and 0.634 mL of triethylamine (TEA) was added. After thorough stirring, the solution was transferred to a polytetrafluoroethylene-lined autoclave and maintained at 120 °C for 24 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0105] Experimental Example 3-2

[0106] 1.2667 g of DBP ligand and 1 g of zinc acetate dihydrate were dissolved in 30 mL of DMF, and 0.634 mL of triethylamine (TEA) was added. After thorough stirring, the solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 120 °C for 24 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0107] Experimental Example 3-3

[0108] 0.756 g of 1,2-BDC ligand and 1 g of zinc acetate dihydrate were dissolved in 30 mL of DMF, and 0.634 mL of triethylamine (TEA) was added. After thorough stirring, the solution was transferred to a polytetrafluoroethylene-lined autoclave and maintained at 180 °C for 18 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0109] Experimental Examples 3-4

[0110] 1.2667 g of DBP ligand and 1 g of zinc acetate dihydrate were dissolved in 30 mL of DMF, and 0.634 mL of triethylamine (TEA) was added. After thorough stirring, the solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 18 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0111] (4) Preparation of PAE-based Co-MOFs

[0112] Experimental Example 4-1

[0113] 87.237 mg (15 mmol / L) Co(NO3)2·6H2O and 33.226 mg (10 mmol / L) 1,2-BDC were dissolved in 40 mL of deionized water. The initial pH of the solution was 6, and the pH was adjusted to 2 with 1 mol / L HCl. Parallel experiments were performed at pH 4. After thorough stirring, the solution was transferred to a polytetrafluoroethylene-lined autoclave and kept at 120 °C for 18 h. After cooling, the solution was washed with DMF and deionized water at 10,000 rpm and dried at 70 °C for 12 h.

[0114] Experimental Example 4-2

[0115] 87.237 mg (15 mmol / L) Co(NO3)2·6H2O and 55.67 mg (10 mmol / L) DBP were dissolved in 40 mL of deionized water. The initial pH of the solution was 6, and the pH was adjusted to 2 with 1 mol / L HCl. Parallel experiments were performed at pH 4. After thorough stirring, the solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 120 °C for 18 h. After cooling, the solution was washed with DMF and deionized water at 10,000 rpm and dried at 70 °C for 12 h.

[0116] Experimental Example 4-3

[0117] Adjust the pH to 2 using 1 mol / L HCl, and repeat the rest of the steps.

[0118] Experimental Example 4-4

[0119] Adjust the pH to 4 using 1 mol / L HCl, and repeat the rest of the steps.

[0120] Experimental Examples 4-5 to 4-8

[0121] The temperature was maintained at 180 ℃ for 18 h, and the remaining steps were the same as in Experiments 1-4.

[0122] Experimental Examples 4-9

[0123] 0.5 g of cobalt salt and 0.1427 g of ligand 1,2-BDC were dissolved in a mixed solvent (10 DMF + 10 H₂O + 10 EtOH). The resulting mixture was vigorously stirred until homogeneous at room temperature. The solution was then transferred to a high-pressure reactor lined with polytetrafluoroethylene (PTFE) and reacted at 180 °C for 60 h.

[0124] Experimental Example 4-10

[0125] 0.5 g of cobalt salt and 0.1427 g of ligand 1,2-BDC were dissolved in a mixed solvent (10 DMF + 10 H₂O + 10 EtOH). The resulting mixture was vigorously stirred at room temperature until homogeneous, and 0.25 g of PVP was added. The solution was transferred to a high-pressure reactor lined with polytetrafluoroethylene, and the reaction was carried out at 180 °C for 60 h.

[0126] Experimental Example 4-11

[0127] 0.5 g of cobalt salt and 0.2392 g of ligand DBP were dissolved in a mixed solvent (10 DMF + 10 H₂O + 10 EtOH). The resulting mixture was vigorously stirred until homogeneous at room temperature. The solution was then transferred to a high-pressure reactor lined with polytetrafluoroethylene (PTFE) and reacted at 180 °C for 60 h.

[0128] Experimental Example 4-12

[0129] 0.5 g of cobalt salt and 0.2392 g of ligand DBP were dissolved in a mixed solvent (10 DMF + 10 H₂O + 10 EtOH). The resulting mixture was vigorously stirred at room temperature until homogeneous, and 0.25 g of PVP was added. The solution was transferred to a high-pressure reactor with a polytetrafluoroethylene liner, and the reaction temperature was 180 °C for 60 h.

[0130] Preparation of a monolithic Co-MOF / NF catalyst based on NF: The above mixed solution and NF were transferred together to a high-pressure reactor with a polytetrafluoroethylene liner. The reaction temperature was 180℃ and the reaction time was 60 h. After the reaction, the mixture was washed with DMF and deionized water to obtain Co-MOF / NF.

[0131] (5) Preparation of Ni-MOF based on PAEs

[0132] Experimental Example 5-1

[0133] 0.5 g of nickel salt and 0.1247 g of ligand 1,2-BDC were dissolved in a mixed solvent (10 DMF + 10 H₂O + 10 EtOH). The resulting mixture was vigorously stirred until homogeneous at room temperature. The solution was then transferred to a high-pressure reactor lined with polytetrafluoroethylene (PTFE) and reacted at 180 °C for 60 h.

[0134] Experimental Example 5-2

[0135] 0.5 g of nickel salt and 0.1247 g of ligand 1,2-BDC were dissolved in a mixed solvent (10 DMF + 10 H₂O + 10 EtOH). The resulting mixture was vigorously stirred at room temperature until homogeneous, and 0.25 g of PVP was added. The solution was transferred to a high-pressure reactor lined with polytetrafluoroethylene, and the reaction was carried out at 180 °C for 60 h.

[0136] Experimental Example 5-3

[0137] 0.5 g of nickel salt and 0.2392 g of ligand DBP were dissolved in a mixed solvent (10 DMF + 10 H₂O + 10 EtOH). The resulting mixture was vigorously stirred until homogeneous at room temperature. The solution was then transferred to a high-pressure reactor lined with polytetrafluoroethylene (PTFE) and reacted at 180 °C for 60 h.

[0138] Experimental Example 5-4

[0139] 0.5 g of nickel salt and 0.2392 g of ligand DBP were dissolved in a mixed solvent (10 DMF + 10 H₂O + 10 EtOH). The resulting mixture was vigorously stirred at room temperature until homogeneous, and 0.25 g of PVP was added. The solution was transferred to a high-pressure reactor with a polytetrafluoroethylene liner, and the reaction temperature was 180 °C for 60 h.

[0140] Preparation of monolithic Ni-MOF / NF catalyst based on NF: The above mixed solution and NF were transferred together to a high-pressure reactor with a polytetrafluoroethylene liner. The reaction temperature was 180℃ and the reaction time was 60 h. After the reaction, the mixture was washed with DMF and deionized water to obtain Ni-MOF / NF.

[0141] (6) Preparation of CoNi-MOF based on PAEs

[0142] Experimental Example 6-1

[0143] 0.25 g of nickel salt, 0.25 g of cobalt salt, and 0.1247 g of ligand 1,2-BDC were dissolved in 40 mL of H₂O. The resulting mixture was vigorously stirred until homogeneous at room temperature. The solution was then transferred to a high-pressure reactor lined with polytetrafluoroethylene (PTFE) and reacted at 120 °C for 18 h.

[0144] Experimental Example 6-2

[0145] 0.25 g of nickel salt, 0.25 g of cobalt salt, and 0.2392 g of ligand DBP were dissolved in 40 mL of H₂O. The resulting mixture was vigorously stirred until homogeneous at room temperature. The solution was then transferred to a high-pressure reactor lined with polytetrafluoroethylene (PTFE) and reacted at 120 °C for 18 h.

[0146] Experimental Example 6-3

[0147] 0.25 g of nickel salt and 0.1247 g of ligand 1,2-BDC were dissolved in 40 mL of H₂O. The resulting mixture was stirred vigorously at room temperature until homogeneous. The solution was then transferred to a high-pressure reactor lined with polytetrafluoroethylene (PTFE) and reacted at 180 °C for 18 h.

[0148] Experimental Example 6-4

[0149] 0.25 g of nickel salt, 0.25 g of cobalt salt, and 0.2392 g of ligand DBP were dissolved in 40 mL of H₂O. The resulting mixture was vigorously stirred until homogeneous at room temperature. The solution was then transferred to a high-pressure reactor lined with polytetrafluoroethylene (PTFE) and reacted at 180 °C for 18 h.

[0150] Experimental Example 6-5

[0151] 0.125 g (0.4295 mmol) Co(NO3)2·6H2O and 0.125 g (0.4295 mmol) Ni(NO3)2·6H2O were dissolved in 30 mL of a mixed solution of deionized water, ethanol, and DMF (H2O:EtOH:DMF = 1:1:1). After thorough stirring, the solution was transferred to a polytetrafluoroethylene-lined autoclave and maintained at 180 °C for 60 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0152] Experimental Example 6-6

[0153] 0.125 g (0.4295 mmol) Co(NO3)2·6H2O and 0.125 g (0.4295 mmol) Ni(NO3)2·6H2O were dissolved in 30 mL of a mixed solution of deionized water, ethanol, and DMF (H2O:EtOH:DMF = 1:1:1). 0.25 g of PVP (K30 or K90) was added, and the mixture was stirred thoroughly. The solution was then transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 60 h. After cooling, the mixture was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0154] Experimental Examples 6-7

[0155] 0.125 g (0.4295 mmol) Co(NO3)2·6H2O and 0.125 g (0.4295 mmol) Ni(NO3)2·6H2O were dissolved in 30 mL of a mixed solution of deionized water, ethanol, and DMF (H2O:EtOH:DMF = 1:1:1). After thorough stirring, the solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 60 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0156] Experimental Examples 6-8

[0157] 0.125 g (0.4295 mmol) Co(NO3)2·6H2O and 0.125 g (0.4295 mmol) Ni(NO3)2·6H2O were dissolved with 55.67 mg (0.4295 mmol) DBP in 30 mL of a mixed solution of deionized water-ethanol-DMF (H2O:EtOH:DMF=1:1:1). 0.25 g PVP (K30 or K90) was added, and the mixture was stirred thoroughly. The solution was then transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 60 h. After cooling, the mixture was washed with DMF and EtOH at 10000 rpm and dried at 70 °C for 12 h.

[0158] Preparation of monolithic CoNi-MOF / NF catalyst based on NF: The above mixed solution and NF were transferred together to a high-pressure reactor with a polytetrafluoroethylene liner. The reaction temperature was 180℃ and the reaction time was 60 h. After the reaction, the mixture was washed with DMF and deionized water to obtain CoNi-MOF / NF.

[0159] Table 1: Ligand Ratio Experiments in Fe-MOF Preparation Schemes

[0160]

[0161] Table 2: Acid-base tests of Fe-MOF preparation methods

[0162]

[0163] Table 3: Solvent Temperature Experiments for Fe-MOF Preparation Schemes

[0164]

[0165] XRD analysis revealed that the product of FeCl3·6H2O after the above hydrothermal synthesis was almost identical to the standard card PDF#72-0469 of Fe2O3, proving that phthalic acid ligands are difficult to coordinate with Fe.

[0166] Table 4: Acid-base tests of Cu-MOF preparation methods

[0167]

[0168] XRD analysis revealed that the product of CuCl2·2H2O after hydrothermal synthesis was almost identical to the standard card PDF#81-1841 for CuCl. Cuprous chloride is easily oxidized to green basic copper chloride when exposed to air, and decomposes into brown upon exposure to light. It is stable in dry air, but easily turns blue to brown when exposed to moisture. Comparing the physical properties of the synthesized material, the synthesized product was determined to be CuCl. Experiments showed that phthalic acid ligands are difficult to coordinate with Cu under these conditions.

[0169] Table 5: Experimental conditions for Zn-MOF preparation scheme

[0170]

[0171] XRD analysis revealed that the white product of zinc acetate after hydrothermal synthesis was almost identical to the standard card PDF#36-4151 for ZnO, indicating that the synthesized product was ZnO. Experiments showed that phthalic acid ligands had difficulty coordinating with Zn under these conditions, which may also be due to excessively high temperature.

[0172] Table 6: Experimental Conditions for Co-MOF Preparation Scheme 1

[0173]

[0174] The method failed to generate the product.

[0175] Table 7: Experimental Conditions for Co-MOF Preparation Scheme 2

[0176]

[0177] The reaction produced Co-MOF.

[0178] Table 8: Experimental conditions for Ni-MOF preparation scheme

[0179]

[0180] Table 9: Experimental conditions for Co,Ni-MOF preparation scheme 1

[0181]

[0182] Table 10: Experimental conditions for Co,Ni-MOF preparation scheme 2

[0183]

[0184] Co and Ni can form bimetallic MOFs with phthalic acid or DBP.

[0185] Example 2: Preparation of catalysts and working electrodes with different Ni / Co:Fe ratios

[0186] Experimental Example 7-1

[0187] 0.4 g (1.3744 mmol) of Ni(NO3)2·6H2O and 0.1195 g (0.4295 mmol) of DBP were dissolved in 30 mL of a mixed solution of deionized water, ethanol, and DMF (H2O:EtOH:DMF = 1:1:1). Fe salt (Fe...) was then added. 3+ After thorough stirring, 0.3436 mmol (Fe:Ni = 1:4) of the solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 60 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0188] Preparation of monolithic Fe3O4-Ni-MOF / NF (Fe:Ni=1:4) catalyst based on NF: The above mixed solution and NF were transferred together to a high-pressure reactor with a polytetrafluoroethylene liner. The reaction temperature was 180℃ and the reaction time was 60h. After the reaction, the mixture was washed with DMF and deionized water to obtain Fe3O4-Ni-MOF / NF (Fe:Ni=1:4).

[0189] Experimental Example 7-2

[0190] 0.3 g (1.0308 mmol) of Ni(NO3)2·6H2O and 0.1195 g (0.4295 mmol) of DBP were dissolved in 30 mL of a mixed solution of deionized water, ethanol, and DMF (H2O:EtOH:DMF = 1:1:1). Fe salt (Fe...) was then added. 3+ After thorough stirring, 0.6872 mmol (Fe:Ni = 2:3) of the solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 60 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0191] Preparation of monolithic Fe3O4-Ni-MOF / NF (Fe:Ni=2:3) catalyst based on NF: The above mixed solution and NF were transferred together to a high-pressure reactor with a polytetrafluoroethylene liner. The reaction temperature was 180℃ and the reaction time was 60h. After the reaction, the mixture was washed with DMF and deionized water to obtain Fe3O4-Ni-MOF / NF (Fe:Ni=2:3).

[0192] Experimental Example 7-3

[0193] 0.2 g (0.6872 mmol) of Ni(NO3)2·6H2O and 0.1195 g (0.4295 mmol) of DBP were dissolved in 30 mL of a mixed solution of deionized water, ethanol, and DMF (H2O:EtOH:DMF = 1:1:1). Fe salt (Fe...) was then added. 3+ After thorough stirring, 1.0308 mmol (Fe:Ni=3:2) of the solution was transferred to a high-pressure reactor lined with polytetrafluoroethylene and kept at 180 °C for 60 h. After cooling, the solution was washed with DMF and EtOH at 10000 rpm and dried at 70 °C for 12 h.

[0194] Preparation of monolithic Fe3O4-Ni-MOF / NF (Fe:Ni=3:2) catalyst based on NF: The above mixed solution and NF were transferred together to a high-pressure reactor with a polytetrafluoroethylene liner. The reaction temperature was 180℃ and the reaction time was 60 h. After the reaction, the mixture was washed with DMF and deionized water to obtain Fe3O4-Ni-MOF / NF (Fe:Ni=3:2).

[0195] Experimental Example 7-4

[0196] 0.1 g (0.3436 mmol) of Ni(NO3)2·6H2O and 0.1195 g (0.4295 mmol) of DBP were dissolved in 30 mL of a mixed solution of deionized water, ethanol, and DMF (H2O:EtOH:DMF = 1:1:1). Fe salt (Fe...) was then added. 3+ After thorough stirring, 1.3744 mmol (Fe:Ni = 4:1) of the above solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 60 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0197] Preparation of monolithic Fe3O4-Ni-MOF / NF (Fe:Ni=4:1) catalyst based on NF: The above mixed solution and NF were transferred together to a high-pressure reactor with a polytetrafluoroethylene liner. The reaction temperature was 180℃ and the reaction time was 60h. After the reaction, the mixture was washed with DMF and deionized water to obtain Fe3O4-Ni-MOF / NF (Fe:Ni=4:1).

[0198] Experimental Example 7-5

[0199] 0.25 g (0.859 mmol) of Co(NO3)2·6H2O and 0.1195 g (0.4295 mmol) of DBP were dissolved in 30 mL of a mixed solution of deionized water, ethanol, and DMF (H2O:EtOH:DMF = 1:1:1). Fe salt (Fe...) was then added. 3+ After thorough stirring, 0.859 mmol (Co:Fe = 1:1) of the solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 60 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0200] Preparation of monolithic Fe3O4-Co-MOF / NF (Co:Fe = 1:1) catalyst based on NF: The above mixed solution and NF were transferred together to a high-pressure reactor with a polytetrafluoroethylene liner. The reaction temperature was 180℃ and the reaction time was 60 h. After the reaction, the mixture was washed with DMF and deionized water to obtain Fe3O4-Co-MOF / NF (Co:Fe = 1:1).

[0201] Experimental Example 7-6

[0202] 0.4 g (1.3744 mmol) of Co(NO3)2·6H2O and 0.1195 g (0.4295 mmol) of DBP were dissolved in 30 mL of a mixed solution of deionized water, ethanol, and DMF (H2O:EtOH:DMF = 1:1:1). Fe salt (Fe...) was then added. 3+ After thorough stirring, 0.3436 mmol (Co:Fe = 4:1) of the solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 60 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0203] Preparation of monolithic Fe3O4-Co-MOF / NF (Co:Fe = 4:1) catalyst based on NF: The above mixed solution and NF were transferred together to a high-pressure reactor with a polytetrafluoroethylene liner. The reaction temperature was 180℃ and the reaction time was 60 h. After the reaction, the mixture was washed with DMF and deionized water to obtain Fe3O4-Co-MOF / NF (Co:Fe = 4:1).

[0204] Experimental Example 7-7

[0205] 0.2 g (0.6872 mmol) of Co(NO3)2·6H2O and 0.1195 g (0.4295 mmol) of DBP were dissolved in 30 mL of a mixed solution of deionized water, ethanol, and DMF (H2O:EtOH:DMF = 1:1:1). Fe salt (Fe...) was then added. 3+ After thorough stirring, 1.0308 mmol (Co:Fe = 2:3) of the solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 60 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0206] Preparation of monolithic Fe3O4-Co-MOF / NF (Co:Fe = 2:3) catalyst based on NF: The above mixed solution and NF were transferred together to a high-pressure reactor with a polytetrafluoroethylene liner. The reaction temperature was 180℃ and the reaction time was 60 h. After the reaction, the mixture was washed with DMF and deionized water to obtain Fe3O4-Co-MOF / NF (Co:Fe = 2:3).

[0207] Experimental Examples 7-8

[0208] 0.4 g (1.3744 mmol) of Co(NO3)2·6H2O and 0.1195 g (0.4295 mmol) of DBP were dissolved in 30 mL of a mixed solution of deionized water, ethanol, and DMF (H2O:EtOH:DMF = 1:1:1). Fe salt (Fe...) was then added. 3+ After thorough stirring, 1.0308 mmol (Co:Fe = 4:3) of the solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 60 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0209] Preparation of monolithic Fe3O4-Co-MOF / NF (Co:Fe = 4:3) catalyst based on NF: The above mixed solution and NF were transferred together to a high-pressure reactor with a polytetrafluoroethylene liner. The reaction temperature was 180℃ and the reaction time was 60 h. After the reaction, the mixture was washed with DMF and deionized water to obtain Fe3O4-Co-MOF / NF (Co:Fe = 4:3).

[0210] Preparation of catalysts and working electrodes of different Ni / Co:Fe

[0211]

[0212] Example 3: Catalysts prepared with different ligands and different metal sources

[0213] Experimental Example 8-1

[0214] 0.25 g (0.859 mmol) of Ni(NO3)2·6H2O and 0.4295 mmol of 1,2-BDC were dissolved in 30 mL of a mixed solution of deionized water, ethanol, and DMF (H2O:EtOH:DMF = 1:1:1). Fe was then added. 3+ After thorough stirring with 0.859 mmol of salt (Fe:Ni = 1:1), the above solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 60 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0215] Based on NF, a monolithic Fe3O4-Ni-MOF / NF (1,2-BDC, Fe 3+ Preparation of the Fe:Ni=1:1 catalyst: The above mixed solution and NF were transferred together to a high-pressure reactor with a polytetrafluoroethylene liner. The reaction temperature was 180℃ and the reaction time was 60 h. After the reaction, the mixture was washed with DMF and deionized water to obtain Fe3O4-Ni-MOF / NF (1,2-BDC, Fe 3+ (Fe:Ni = 1:1). Experimental Example 8-2

[0216] 0.25 g (0.859 mmol) of Ni(NO3)2·6H2O and 0.4295 mmol of DBP were dissolved in 30 mL of a mixed solution of deionized water, ethanol, and DMF (H2O:EtOH:DMF = 1:1:1). Fe was added. 2+ After thorough stirring with 0.859 mmol of salt (Fe:Ni = 1:1), the above solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and maintained at 180 °C for 60 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0217] Based on NF, a monolithic Fe3O4-Ni-MOF / NF (DBP, Fe 2+ Preparation of the catalyst (Fe:Ni=1:1): The above mixed solution and NF were transferred together to a high-pressure reactor with a polytetrafluoroethylene liner. The reaction temperature was 180℃ and the reaction time was 60 h. After the reaction, the mixture was washed with DMF and deionized water to obtain Fe3O4-Ni-MOF / NF (DBP, Fe 2+ (Fe:Ni = 1:1).

[0218] Experimental Example 8-3

[0219] 0.25 g (0.859 mmol) of Ni(NO3)2·6H2O and 0.4295 mmol of 1,2-BDC were dissolved in 30 mL of a mixed solution of deionized water, ethanol, and DMF (H2O:EtOH:DMF = 1:1:1). Fe was then added. 2+ After thorough stirring of the salt (Fe:Ni = 1:1), the above solution was transferred to a high-pressure reactor lined with polytetrafluoroethylene and maintained at 180 °C for 60 h. After cooling, the solution was washed with DMF and EtOH at 10,000 rpm and dried at 70 °C for 12 h.

[0220] Based on NF, a monolithic Fe3O4-Ni-MOF / NF (1,2-BDC, Fe 2+ Preparation of the Fe:Ni=1:1 catalyst: The above mixed solution and NF were transferred together to a high-pressure reactor with a polytetrafluoroethylene liner. The reaction temperature was 180℃ and the reaction time was 60 h. After the reaction, the mixture was washed with DMF and deionized water to obtain Fe3O4-Ni-MOF / NF (1,2-BDC, Fe 2+ (Fe:Ni = 1:1).

[0221] Experimental Example 8-4

[0222] 0.25 g (0.859 mmol) of Co(NO3)2·6H2O and 0.4295 mmol of 1,2-BDC were dissolved in 30 mL of a mixed solution of deionized water, ethanol, and DMF (H2O:EtOH:DMF = 1:1:1). Fe was then added. 3+ After thorough stirring of the salt (Fe:Co=2:3), the above solution was transferred to a high-pressure reactor lined with polytetrafluoroethylene and maintained at 180 °C for 60 h. After cooling, the solution was washed with DMF and EtOH at 10000 rpm and dried at 70 °C for 12 h.

[0223] Based on NF, a monolithic Fe3O4-Co-MOF / NF (1,2-BDC, Fe 3+ Preparation of the Fe:Co=2:3) catalyst: The above mixed solution and NF were transferred together to a high-pressure reactor with a polytetrafluoroethylene liner. The reaction temperature was 180℃ and the reaction time was 60 h. After the reaction, the mixture was washed with DMF and deionized water to obtain Fe3O4-Co-MOF / NF (1,2-BDC, Fe 3+ (Fe:Co = 2:3).

[0224]

[0225] from Figure 3 , Figure 6 It can be seen that different metal ratios alter the catalyst surface structure; the increased Fe content leads to large-scale nanoparticle aggregation on the surfaces of Ni-MOF and Co-MOF. From... Figures 7-10 The OER and HER performance data show that the optimal performance is achieved when the Ni-Fe ratio is 1:1 and the Co-Fe ratio is 3:2.

[0226] At room temperature, using a standard three-electrode system in 1.0 M KOH aqueous solution, the OER activity of Ni-MOF(DBP) / NF (Experimental Examples 5-4) and Fe3O4-Ni-MOF(DBP) / NF (Examples) was measured by LSV. Figure 7 All potentials are referenced to RHE. Compared with Ni-MOF(DBP) / NF, Fe3O4-Ni-MOF(DBP) / NF exhibits a significantly lower OER overpotential (η) at 10 mA cm⁻¹. −2 It requires 233 mV at 100 mA cm⁻¹ −2 The required voltage is 326 mV. This performance significantly surpasses that of commercial RuO2 / NF. The synthesis of Ni-MOF was optimized by evaluating alternative precursors. The catalyst prepared using Fe(NO3)3·9H2O and DBP showed higher current density in the high potential region, reflecting excellent OER activity. The OER activity of Fe3O4-Ni-MOF(DBP) / NF with different metal ratios was systematically evaluated. Figure 9 A 1:1 Ni / Fe ratio was determined to be optimal at 10 and 100 mA cm⁻¹. −2 The overpotential is lowest at this point. OER performance decreases with further increase in Fe content.

[0227] Under the same conditions, the OER activity of Co-MOF(DBP) / NF (Experimental Examples 4-12) and Fe3O4-Co-MOF(DBP) / NF (Example) was measured by LSV. Figure 10 A) Evaluation was conducted. Co-MOF(DBP) / NF and CoNi-MOF(DBP) / NF showed improvements over Co-MOF(DBP) / NF. Furthermore, Fe3O4-Co-MOF(DBP) / NF exhibited OER performance similar to Fe3O4-Ni-MOF(DBP) / NF. Replacing DBP with 1,2-BDC in the synthesis yielded Fe3O4-Co-MOF(BDC) / NF catalysts with those of Fe3O4-Co-MOF(DBP) / NF. Figure 10 B). The OER activity of Fe3O4-Co-DBP / NF with different metal ratios was then investigated. Figure 10 C). A Ni / Fe ratio of 3:2 was determined to be optimal at 10 and 100 mA cm⁻¹.−2 The overpotential is lowest at this point. OER performance decreases with further increase in Fe content.

[0228] use Figure 13 Using the water displacement gas collection method, the Faraday efficiencies of OER and HER were calculated to be 98.37% and 96.53%, respectively. This invention constructs a high-performance bifunctional catalytic system using 1,2-BDC, which has low toxicity after degradation, as the catalyst ligand for electrocatalysis. The results show that the performance of the example material is superior to other comparative materials, making it a green and efficient water electrolysis catalyst.

[0229] Example 4

[0230] The preparation of a bifunctional MOF electrocatalyst using waste PET gas as an example includes the following steps:

[0231] Pretreatment of PET fragments: After rinsing off surface impurities, the fragments are broken into small pieces, and 0.11 g is weighed. 0.5 g of nickel nitrate hexahydrate, 0.25 g of PVP, and PET fragments are stirred in a mixed solution of 10 mL ethanol, 10 mL deionized water, and 10 mL DMF for 30 min. The mixture is then transferred to a polytetrafluoroethylene-lined reactor and reacted at 180 °C for 60 h.

[0232] Results analysis: The SEM morphology was sheet-like, with smaller and more elongated sheets and fewer impurities. The ligands reacted almost completely, and the OER and HER performance was comparable to that of the product in Experiment 5-4.

[0233] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for one-pot synthesis of bifunctional MOF electrocatalysts based on waste pollutants, characterized in that, Includes the following steps: Weigh PAE waste, nickel salt and / or cobalt salt, PVP, a mixed solvent of ethanol, deionized water and DMF in a volume ratio of 1:1:1, and trivalent iron salt, mix thoroughly, and then transfer to a polytetrafluoroethylene-lined reactor. React at 100~200℃ for 24~60 h to obtain Fe3O4-doped MOF material Fe3O4-Ni(Co)-MOF with Ni and / or Co nodes. The molar ratio of metal salt to PAEs in PAEs waste is 1~3:1; The Fe:Ni molar ratio is 1~4:1~4 or the Fe:Co molar ratio is 1~3:1~4.

2. The method for one-pot synthesis of bifunctional MOF electrocatalysts based on waste pollutants according to claim 1, characterized in that, PAEs are used as plasticizers in PAE waste; Alternatively, PAEs waste refers to the waste from the dismantling of photovoltaic modules containing PAEs.

3. The method for one-pot synthesis of bifunctional MOF electrocatalysts based on waste pollutants according to claim 1, characterized in that, PAEs are at least one of di(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), diisobutyl phthalate (DIBP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), dioctyl phthalate (DNOP), diisooctyl phthalate (DIOP), dimethyl phthalate (DMP), diethyl phthalate (DEP), dipropyl phthalate (DPrP), dipentyl phthalate (DPP), and dinonyl phthalate (DNP).

4. The method for one-pot synthesis of bifunctional MOF electrocatalysts based on waste pollutants according to claim 1, characterized in that, The trivalent ferric salt is at least one of ferric chloride hexahydrate, ferric sulfate nonahydrate, and ferric nitrate nonahydrate.

5. The method for one-pot synthesis of bifunctional MOF electrocatalysts based on waste pollutants according to claim 1, characterized in that, It also includes the following steps: nickel foam NF is also placed in the high-pressure reactor, and MOF grows on its surface.

6. The method for one-pot synthesis of bifunctional MOF electrocatalysts based on waste pollutants according to claim 1, characterized in that, The amount of PVP added is 41% to 44% of the total mass of the metal salt; And / or, Fe:Ni molar ratio 1:1 or Fe:Co molar ratio 2:

3.

7. A bifunctional MOF electrocatalyst, characterized in that, Obtained by the method according to any one of claims 1 to 7.

8. The application of the bifunctional MOF electrocatalyst as described in claim 7, characterized in that, Used for electrocatalytic hydrolysis.

9. The application of the bifunctional MOF electrocatalyst according to claim 8, characterized in that, The process includes the following steps: using an electrode containing a bifunctional MOF electrocatalyst as the working electrode, forming a three-electrode system with a reference electrode and an auxiliary electrode for electrocatalytic hydrolysis, with the electrocatalytic hydrolysis environment being alkaline.

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