Preparation of Ru modified Ni-MOF electrocatalyst and application of Ru modified Ni-MOF electrocatalyst in benzyl alcohol oxidation assisted hydrogen evolution
By introducing trace amounts of Ru into Ni-MOF materials, the NiRu-MOF catalyst was constructed, and the problem of slow OER reaction kinetics was solved, and the oxidation activity of benzyl alcohol and the energy conversion efficiency were improved.
Patent Information
- Application Number
- CN202510305540.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-14
- Publication Date
- 2025-07-04
AI Technical Summary
During the traditional process of electrolysis of water, the oxygen evolution reaction (OER) reaction kinetics are slow and the theoretical potential is high, resulting in low energy conversion efficiency and difficult to effectively drive.
Ni-MOF material is used as an electrocatalyst, and the electronic structure is adjusted by introducing trace amounts of precious metal Ru, and the bimetallic organic frame material NiRu-MOF is constructed for benzyl alcohol oxidation and auxiliary hydrogen evolution reaction.
The electrode potential of benzyl alcohol oxidation is reduced, the catalytic activity is improved, the energy consumption of hydrogen evolution reaction is reduced, and the energy utilization efficiency is improved.
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Figure CN120248345A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a novel metal-organic framework material (Ni-MOF) formed with 1,2,4,5-tetrakis(4-carboxyphenyl)benzene as an organic ligand and transition metal nickel as a metal center. Ni-MOF shows excellent performance in the test of preparing a catalyst electrode material for benzyl alcohol. By utilizing the structural advantages of the metal-organic framework template, a second metal Ru is introduced through a doping strategy. It is found through experiments that the introduction of a trace amount of Ru can effectively adjust the electronic structure of Ni-MOF, thereby improving the electrochemistry activity. Background Art As a green, clean and efficient renewable energy, hydrogen energy is regarded as the key to future energy transformation due to its high energy density and the combustion product being only water. Then electrocatalytic water splitting is a key step in hydrogen production, and hydrogen evolution and oxygen evolution have always been the research hotspots in the catalytic field. However, in the traditional electrolytic water process, the hydrogen evolution reaction (HER) occurs at the cathode, and the oxygen evolution reaction (OER) occurs at the anode. Compared with HER, OER is a relatively complex four-electron transfer process, with slow reaction kinetics in nature and a relatively high theoretical potential (1.23 V vs. RHE), resulting in a large overpotential to drive it, greatly reducing the energy conversion. Then we break the traditional thinking and replace OER with a thermodynamically more favorable small molecule oxidation reaction to construct a hybrid water splitting system. These organic oxidation reactions can not only reduce the battery voltage for hydrogen production, but also produce value-added products and can be coupled with the cathode hydrogen evolution reaction to more effectively improve the energy utilization efficiency.
[0002] MOFs are metal-organic framework compounds, which are formed by the self-assembly connection of inorganic metal centers (metal ions or metal clusters) and bridging organic ligands to form a class of crystalline porous materials with a periodic network structure. At present, a metal-organic framework material constructed by the coordination of metal ions or metal clusters and organic ligands has an extremely high specific surface area, adjustable coordination pore diameter, adjustable pore size, and diversity of framework components, so it is considered to be an extremely important electrocatalyst. MOFs metal-organic framework materials have attracted much attention because of their unique structures such as high specific surface area, adjustable coordination pore diameter, adjustable pore size, and diversity of framework components, and are thus considered to be an extremely important electrocatalyst. In recent years, metal-organic frameworks (MOFs) have been widely used as a catalyst in the electrocatalytic field. This is because MOFs have a large specific surface area and redox ability, providing rich active sites for electrocatalytic reactions. The starting point of concern in this patent is to explore the oxidation performance of a newly synthesized Ni-MOF for benzyl alcohol, and to construct a bimetallic MOF catalyst to further explore its performance for benzyl alcohol oxidation and the construction of hybrid water splitting. Summary of the Invention
[0003] The present invention provides a method for synthesizing a metal-organic framework material (Ni-MOF) formed with 1,2,4,5-tetrakis(4-carboxyphenyl)benzene as a ligand and transition metal nickel as a metal center. Its chemical general formula is Ni3C 52 H 41 O 14 N.
[0004] Its compound structural formula is as follows: Weigh the ligand 1,2,4,5-tetrakis(4-carboxyphenyl)benzene, nickel chloride hexahydrate, lithium hydroxide, and N,N-dimethylacetamide (DMA). After ultrasonic dispersion of 60-69% HNO3 by mass concentration, add them to a glass bottle, seal it, and under solvothermal reaction conditions of 100-120 °C for 18-48 hours, and slowly cool to room temperature at a uniform speed of 2-3 °C / h to obtain green hexagonal columnar crystals. Dry to obtain the material for preparing electrode materials to test the oxidation performance of benzyl alcohol.
[0005] The molar ratio of the ligand 1,2,4,5-tetrakis(4-carboxyphenyl)benzene, nickel metal salt, and lithium hydroxide is 1:10:120 - 1:20:140.
[0006] The volume of DMA is 1-4 ml, and the dropping amount of nitric acid is 1-8 drops, where the mass concentration of nitric acid is 60-69%.
[0007] Further preferably, the molar ratio of the ligand 1,2,4,5-tetrakis(4-carboxyphenyl)benzene, nickel metal salt, and lithium hydroxide is 3:10:100; the solvothermal reaction conditions are 120 °C and the reaction time is 48 hours.
[0008] The volume of DMA is 4 ml, the dropping amount of nitric acid is 8 drops, and its mass concentration is 69%.
[0009] A trace amount of precious metal Ru is also introduced into the nickel-based metal-organic framework material to prepare a bimetallic metal-organic framework material NiRu-MOF.
[0010] Add the synthesized Ni-MOF to the prepared anhydrous ethanol dispersion system of RuCl3, and obtain NiRu-MOF through solvothermal reaction.
[0011] The concentration of the RuCl3 anhydrous ethanol solution is 1-3 mg / ml. In some embodiments, it can be one of NiRu-MOF-1, NiRu-MOF-2, and NiRu-MOF-3.
[0012] The nickel-based metal-organic framework material also includes a chemical formula of Ni3C 52 H 41 O14 Crystalline materials of N, where the room temperature involved in the present invention refers to the ambient temperature under normal pressure.
[0013] In some embodiments, the bimetallic nickel-ruthenium-based metal-organic framework material includes any one of NiRu-MOF-1, NiRu-MOF-2, and NiRu-MOF-3.
[0014] Application of the bimetallic nickel-ruthenium-based metal-organic framework material prepared by the described method as an electrocatalyst in the oxidation of benzyl alcohol or the assisted hydrogen evolution.
[0015] Application of the nickel-based metal-organic framework material as an electrocatalyst in the oxidation of benzyl alcohol or the assisted hydrogen evolution.
[0016] The crystal synthesized in the present invention was subjected to structure determination using a small molecule single crystal X-ray diffractometer from Rigaku Corporation, Japan. The diffraction intensity and unit cell parameters were measured at 293K using Mo Kα radiation monochromatized by a graphite monochromator. The collected data was subjected to empirical absorption correction using a scanning technique. The obtained results were analyzed by the direct method using the Shelxtl-97 program and refined by full matrix least squares method. The crystallographic data is shown in Table 1 of crystal parameters.
[0017] Table 1 Crystallographic parameter table Brief description of the drawings
[0018] Figure 1 : Three-dimensional stacking diagram of the crystalline metal-organic framework material (Ni-MOF) synthesized in Example 5.
[0019] Figure 2 : XRD spectra of Ni-MOF prepared in Example 5 and NiRu-MOF prepared in Example 6.
[0020] Figure 3 : Infrared spectra of Ni-MOF prepared in Example 5 and NiRu-MOF prepared in Example 6.
[0021] Figure 4 : Thermogravimetric diagrams of Ni-MOF prepared in Example 5 and NiRu-MOF prepared in Example 6.
[0022] Figure 5 : Scanning (SEM) diagram of Ni-MOF prepared in Example 5.
[0023] Figure 6 : LSV diagrams of Ni-MOF prepared in Example 5 and NiRu-MOF prepared in Example 6 in 1 M KOH.
[0024] Figure 7 : LSV diagrams of the Ni-MOF prepared in Example 5 and the NiRu-MOF prepared in Example 6 in 1 M KOH + 0.1 M BA.
[0025] Figure 8 : LSV diagrams of the optimal target sample NiRu-MOF-2 in Example 6 in 1 M KOH + 0.1 M BA and 1 M KOH.
[0026] Figure 9 : HPLC peak diagrams of the electrolysis of the optimal target sample NiRu-MOF-2 in Example 6 at different time intervals.
[0027] Figure 10 : Diagrams of benzyl alcohol conversion and product formation during the electrolysis of the optimal target sample NiRu-MOF-2 in Example 6 at different time intervals.
[0028] Figure 11 : Faraday efficiency diagrams of benzyl alcohol electrolysis of the optimal target sample NiRu-MOF-2 in Example 6 at different electrode potentials.
[0029] Figure 12 : Diagrams of benzyl alcohol consumption rate and yield during the electrolysis of the optimal target sample NiRu-MOF-2 in Example 6 at different electrode potentials.
[0030] Figure 13 : Performance diagrams of the electrolysis of water using NiRu-MOF-2 prepared in Example 6 as the anode and commercial Pt / C (20%) as the cathode. Specific implementation manners
[0031] Example 1 Weigh 0.01 mmol of 1,2,4,5-tetrakis(4-carboxyphenyl)benzene, 0.03 mmol of nickel chloride hexahydrate, 0.3 mmol of lithium hydroxide, and 4 ml of N,N-dimethylacetamide (DMA) in equal amounts and dispense them into 5 small vials. Then, add 1 - 5 drops of 69% HNO3 with a mass concentration to each small vial and dispense them into 5 bottles. Each bottle is numbered from 1 to 5. The reaction is carried out in a sealed 20 ml glass bottle. After ultrasonic treatment for 15 min, it is placed in a sealed oven and reacted at 120 °C for 48 hours, and then cooled to room temperature at a uniform speed of 2 - 3 °C / h. No crystals are produced in all 5 small vials, and the solutions in vials numbered 1 - 3 are more turbid than those in vials 4 and 5.
[0032] Example 2 Weigh out 0.01 mmol of 1,2,4,5-tetrakis(4-carboxyphenyl)benzene, 0.3 mmol of lithium hydroxide, and 4 ml of N,N-dimethylacetamide (DMA) in six small vials. Add 8 drops of 69% HNO₃ to each vial. Number the vials from 1 to 6. Then add 0.03 mmol of nickel(II) chloride hexahydrate, nickel(II) sulfate hexahydrate, nickel(II) perchlorate hexahydrate, nickel(II) nitrate hexahydrate, nickel(II) acetate tetrahydrate, and nickel(II) acetylacetonate to each vial respectively. The reaction is carried out in a sealed 20-ml glass bottle. After ultrasonic treatment for 15 min, place it in a sealed oven and react at 120 °C for 48 h, and then cool it to room temperature at a uniform rate of 2 - 3 °C / h. It is found that crystals are produced in vials 1, 2, 3, and 4, microcrystals are produced in vial 5, and a precipitate is formed in vial 6. However, the crystals in vials 2, 3, and 4 are impure, with impurities adhering to the crystal surface and cracks. The crystals in vial 1 are the purest.
[0033] Example 3 Weigh out 0.01 mmol of 1,2,4,5-tetrakis(4-carboxyphenyl)benzene and 0.03 mmol of nickel(II) chloride hexahydrate, and 4 ml of N,N-dimethylacetamide (DMA) in five small vials. Add 8 drops of 69% HNO₃ to each vial and distribute them into five vials. Number the vials from 1 to 5. Then add 0.3 mmol of LiOH, NaOH, KOH, and potassium carbonate to each vial respectively, and do not add in vial 5. The reaction is carried out in a sealed 20-ml glass bottle. After ultrasonic treatment for 15 min, place it in a sealed oven and react at 120 °C for 48 h, and then cool it to room temperature at a uniform rate of 2 - 3 °C / h. It is found that a precipitate is formed in vials 3 and 4, the solution in vial 5 is relatively clear, and crystals are produced in vials 1 and 2. However, the crystal morphology in vial 2 is not uniform, with some spherical crystals formed. The crystals in vial 1 are the most regular, transparent, and pure.
[0034] Example 4 Weigh out 0.01 mmol of 1,2,4,5-tetrakis(4-carboxyphenyl)benzene and 0.03 mmol of nickel(II) chloride hexahydrate, and 0.3 mmol of lithium hydroxide, and distribute them into five small vials. Then add 4 ml of DMA, DMF, EtOH, DMSO, and H₂O respectively to each vial. Add 8 drops of 69% HNO₃ to each vial and distribute them into five vials. Number the vials from 1 to 5. The reaction is carried out in a sealed 20-ml glass bottle. After ultrasonic treatment for 15 min, place it in a sealed oven and react at 120 °C for 48 h, and then cool it to room temperature at a uniform rate of 2 - 3 °C / h. It is found that crystals are produced in the vial with DMA added in vial 1, and prismatic crystals are formed with good crystal quality.
[0035] Example 5 Weigh 0.03 mmol of nickel chloride hexahydrate, 0.3 mmol of lithium hydroxide, and 4 ml of N,N-dimethylacetamide (DMA) in four small vials. Then add 0.01 mmol, 0.05 mmol, 0.1 mmol, and 0.2 mmol of 1,2,4,5-tetrakis(4-carboxyphenyl)benzene to each vial respectively. Next, add 8 drops of 69% HNO3 to each vial and distribute them into four bottles. Number each bottle from 1 to 4. The reaction is carried out in a sealed 20 ml glass bottle. After ultrasonic treatment for 15 min, place it in a sealed oven and react at 120 °C for 48 hours, and then cool it to room temperature at a uniform rate of 2 - 3 °C / h. It is found that the crystals in vial No. 1 have the highest mass, are the most regular, and have the highest yield. In vials No. 2, 3, and 4, most are precipitates mixed with some microcrystals. From Figure 2 It can be seen that the powder diffraction peaks of the prepared samples are highly consistent with the diffraction peaks of the Ni-MOF simulated by single crystal data. The obtained samples are Ni-MOF materials, and the crystallographic parameters are shown in Table 1.
[0036] Example 6 Place the porous crystalline metal-organic framework material sample (Ni-MOF) collected in Example 5 into the prepared anhydrous ethanol dispersion system of RuCl3. The concentration of the RuCl3 anhydrous ethanol solution is 1 - 3 mg / ml. Number three small vials, numbered 1 - 3, corresponding to the RuCl3 anhydrous ethanol solutions with concentrations of 1 mg / ml, 2 mg / ml, and 3 mg / ml respectively. The RuCl3 anhydrous ethanol solution in each vial is 3 ml, and an appropriate amount of Ni-MOF is taken in each bottle. The reaction is carried out in a sealed 20 ml glass bottle. After standing at room temperature for 5 - 10 min, place it in a sealed oven and react at 80 °C for 3 hours, and then cool it to room temperature at a uniform rate of 2 - 3 °C / h to prepare NiRu-MOF-1, NiRu-MOF-2, and NiRu-MOF-3 respectively. From Figure 2 It can be seen that the powder diffraction peaks of the samples are relatively consistent with the simulated Ni-MOF diffraction peaks, indicating the successful preparation of the samples.
[0037] Example 7 After the porous crystalline metal framework material samples (Ni-MOF and NiRu-MOF) collected in Examples 5 and 6 were ground evenly in an agate mortar, 5 mg was weighed and placed in a 2 ml centrifuge tube respectively. 0.9 ml of isopropanol and 0.1 ml of naphthol were added. After ultrasonic treatment for 60 min, 160 ul of the dispersion was pipetted and dispersed on both sides of the carbon cloth to test the oxidation performance of benzyl alcohol. The oxygen evolution performance was measured after the material was activated and stabilized in 1.0 M KOH solution, and then the benzyl alcohol oxidation curve was measured in 1.0 M KOH + 0.1 M BA. Compared with Ni-MOF, different Ru doping was used to obtain NiRu-MOF, which is beneficial to the sample to maintain long-term and high-efficiency catalytic activity while reducing the electrode potential. Finally, the sample NiRu-MOF-2 only requires an electrode potential of 1.37 V to drive the oxidation of benzyl alcohol, as Figure 6 , Figure 7 . The electrode potentials required for the OER reaction of NiRu-MOF-2 / CC, Ni-MOF / CC, and CC in KOH are 1.550, 1.647, and 1.662 V, respectively. When benzyl alcohol is added to the electrolyte, the electrode potentials required for the BOR (benzyl alcohol oxidation) are 1.370, 1.43, and 1.652 V, respectively. It can be seen that the addition of benzyl alcohol effectively reduces the electrode potential, and the addition of Ru also further reduces the required electrode potential, as Figure 8 . In addition, combining HER with the electrooxidation of benzyl alcohol, commercial Pt / C (20%) was used as the cathode and NiRu-MOF as the anode in the electrolytic cell to achieve mixed electrolysis of water. In the absence of benzyl alcohol, the overall water splitting potential at 10 mA·cm -2 is about 1.73 V compared with RHE. In contrast, after adding benzyl alcohol, the potential relative to RHE is reduced to about 1.57 V, which significantly reduces the working potential of H2O separation by 160 mV, as Figure 13 .
[0038] The sample NiRu-MOF-2 was electrolyzed at a specific current density for different times, and the electrolyte of each time period was taken and analyzed by high performance liquid chromatography for the electrolyte products. It can be seen that at 250 nm, with the change of time, the peak appearance changes and peak positions of benzyl alcohol, benzaldehyde, and benzoic acid can be seen in the peak appearance map of high performance liquid chromatography. With the progress of the reaction time, it is found that the intensities of the peaks of the three substances change significantly, as Figure 9 . After 80000 s, benzyl alcohol is almost completely converted into benzoic acid, and the content of the by-product benzaldehyde is low, as Figure 10 . At the same time, at different electrode potentials, a high conversion rate of benzyl alcohol, selectivity, and yield of benzoic acid are maintained, as Figure 12However, there are some variations in its Faraday efficiency, which may be due to the competitive process of oxygen evolution reaction existing in the catalyst at higher potentials, such as Figure 11 In summary, it shows that the introduction of trace amounts of noble metal Ru can effectively optimize the electronic structure of Ni sites, improve conductivity, thereby enhancing the oxidation performance of the catalyst for benzyl alcohol, accelerating the anodic reaction and simultaneously assisting hydrogen production to reduce the energy consumption required for the reaction.
Claims
1. A nickel-based metal-organic framework material, characterized in that, The chemical formula of the nickel-based metal-organic framework material is Ni3C 52 H 41 O 14 A crystalline material of N. The crystal of this crystalline material belongs to the monoclinic system, the space group is P6 / mmm, and the unit cell parameters are: α = 90°, β = 90°, γ = 120°, a = 30.2967(10) Å, b = 30.2967(10) Å, c = 11.5437(4) Å.
2. A preparation method of a nickel-based metal-organic framework material, characterized in that, The steps are as follows: Add the organic ligand 1,2,4,5-tetrakis(4-carboxyphenyl)benzene, nickel metal salt and lithium hydroxide into a mixed solution of N,N-dimethylacetamide and HNO3, and obtain a nickel-based metal-organic framework material through a solvothermal reaction.
3. The preparation method of the nickel-based metal-organic framework material according to claim 1, wherein, The molar ratio of the ligand 1,2,4,5-tetrakis(4-carboxyphenyl)benzene, nickel metal salt and lithium hydroxide is 1:10-20:120-140.
4. The preparation method of the nickel-based metal-organic framework material according to claim 3, characterized in that, The volume ratio of DMA to nitric acid is 1-4: 0.5-1, where the mass concentration of nitric acid is 60-69%.
5. The preparation method of the nickel-based metal-organic framework material according to claim 1, characterized in that, The solvothermal reaction conditions are 100~120 °C, and the reaction time is 18~48 hours.
6. The preparation method of the nickel-based metal-organic framework material according to claim 5, characterized in that, Trace precious metal Ru is also introduced into the nickel-based metal-organic framework material to prepare NiRu-MOF.
7. The preparation method of the nickel-based metal-organic framework material according to claim 5, characterized in that, Add an anhydrous ethanol dispersion system of RuCl3 to the synthesized Ni-MOF, and obtain NiRu-MOF through a solvothermal reaction.
8. The preparation method of the nickel-based metal-organic framework material according to claim 6, wherein, The concentration of the RuCl3 anhydrous ethanol solution reacting with Ni-MOF is 1-3 mg / ml. Application of the nickel-based metal-organic framework material prepared by the method according to any one of claims 2-8 as an electrocatalyst in the oxidation of benzyl alcohol.
10. A catalyst for catalyzing the oxidation of benzyl alcohol, characterized in that, The nickel-based metal-organic framework material prepared by the method according to any one of claims 2-8.