Bimetal rare earth MOF (Metal Organic Framework) catalyst and application method thereof in preparation of hydrogen peroxide
By synthesizing bimetallic MOF materials through a solvothermal modification strategy, the problems of high energy consumption and heavy pollution in traditional preparation processes have been solved, and efficient and green hydrogen peroxide preparation has been achieved.
Patent Information
- Application Number
- CN202511138890.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-14
- Publication Date
- 2025-11-28
AI Technical Summary
In existing technologies, the traditional anthraquinone method for preparing hydrogen peroxide is energy-intensive and polluting, while the photocatalytic method suffers from low O2 solubility and low selectivity, resulting in low H2O2 solubility.
By employing a Ce doping strategy and a solvothermal modification strategy, bimetallic MOF materials were synthesized, solving the problem of uneven Ce/Mn distribution in in-situ methods.
This method enables efficient preparation of hydrogen peroxide, achieving a greener approach to the traditional anthraquinone method and addressing the issues of high energy consumption and heavy pollution associated with conventional methods.
Smart Images
Figure CN121016852A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application relates to metal organic framework material design and clean energy chemical industry, in particular to a bimetallic rare earth MOF catalyst and an application method thereof in hydrogen peroxide preparation. BACKGROUND
[0002] Hydrogen peroxide (H2O2) as a typical high-value energy carrier compound not only serves as a green oxidant in environmental purification, but also can be used as a clean energy carrier in medical disinfection, water treatment and chemical synthesis. However, the traditional anthraquinone method for preparing H2O2 has multiple stages of circulation, high energy consumption and heavy pollution, and therefore it is urgent to develop a new system for low-carbon preparation of H2O2 based on renewable energy. The traditional synthesis of H2O2 relies on the anthraquinone method (high energy consumption and heavy pollution), and the photocatalytic method is limited by: ① low solubility of O2 (8.26 mg / L at 25 DEG C); ② 4e - / 2e - Oxygen reduction path competition leads to selectivity <75%; ③ although the solubility of ozone reaches 570 mg / L, the yield of H2O2 produced by the separate photolysis of H2O2 is only 13 umol.g -1 ·h -1 The efficiency is low. ④ the addition of a sacrificial agent. The rapid recombination of photo-generated carriers hinders the electron transfer kinetics, forcing the system to rely on a sacrificial agent to maintain the charge separation state, which not only increases the process cost but also causes secondary pollution risk. SUMMARY
[0003] Invention principle: Ce doping strategy is selected, and a bimetallic MOF material (MnCe) MIL-100 is synthesized by a solvothermal modification strategy. The MnCe bimetallic node is constructed, the crystal structure is an octahedral microporous topology, and the problem of uneven distribution of Ce / Mn by in-situ method is solved.
[0004] The (MnCe) MIL-100 catalyst utilizes the high reactivity and high solubility of O3, thereby breaking the inherent limitation of O2. Through the electronic structure modulation of the Mn(III) / Ce(IV) bimetallic node, the charge directional migration induced by the d-f orbital hybridization is realized, and the reaction activation energy of the rate decision step is reduced. Under light irradiation, the efficient conversion of Mn(III) to Mn(II) is realized by photo-generated electrons, and the ·OH free radicals are generated by activating O3 with Mn(II), and the Mn(III) reduction cycle is driven by photo-generated electrons. The coupling of ·OH free radicals to generate H2O2 is driven by the Mn(II) / Mn(III) cycle, which ensures the continuous progress of the catalytic cycle and establishes a solar-driven H2O2 synthesis. The specific process is as follows:
[0005] 2Mn(II)+O3+H2O→2Mn(III)+2·OH
[0006] 2·OH→H2O2
[0007] Mn(III)+e - →Mn(II)
[0008] Technical solution:
[0009] The synthesis process of (MnCe)MIL-100 catalyst includes: (a) dissolving Mn(NO3)2·4H2O and trimesic acid in methanol at a 1:1 molar ratio, and reacting hydrothermally at 120℃ for 3 hours to obtain MIL-100(Mn); (b) mixing MIL-100(Mn) and Ce(NO3)3·6H2O in methanol at a certain Mn:Ce molar ratio, and reacting a second time at 120℃ for 3 hours. The photocatalytic synthesis of H2O2 under ozone in the (MnCe)MIL-100 catalyst process: the catalyst is dispersed in deionized water and sonicated in the dark for 30 minutes. Ozone is bubbled in for 10 minutes until adsorption saturation, with an ozone concentration of 700±50 ppb. A bimetallic MOF catalyst suspension (0.11 g / L) is placed in a quartz photoreactor, and a 300W xenon lamp with a wavelength of 420 nm and a light intensity of 100 mW / cm² is used. 2 Under these conditions, a photocatalytic reaction takes place.
[0010] Beneficial effects
[0011] 1. High efficiency: H2O2 yield is 2-8 times higher than traditional catalysts;
[0012] 2. Green: Pure water system, no sacrificial agents required;
[0013] 3. Stability: After 5 cycles in a strong ozone oxidation environment, the activity remains >87%; Attached Figure Description
[0014] Appendix Figure 1 Example 1: Synthesis flow chart of (Mn1Ce2)MIL-100 catalyst;
[0015] Appendix Figure 2 Example 1: SEM image of the synthesized (Mn1Ce2)MIL-100 catalyst;
[0016] Appendix Figure 3 Elemental mapping spectrum of the (Mn1Ce2)MIL-100 catalyst synthesized in Example 1;
[0017] Appendix Figure 4 Example 1: Comparison of H2O2 yields between (Mn1Ce2)MIL-100 catalyst and (Mn)MIL-100 catalyst;
[0018] Appendix Figure 5 Cyclic test results of the (Mn1Ce2)MIL-100 catalyst synthesized in Example 1;
[0019] Appendix Figure 6 Example 2: SEM image of the synthesized (Mn1Ce0.2)MIL-100 catalyst;
[0020] Appendix Figure 7 Example 5: SEM of the synthesized (Ce)MIL-100 catalyst. Detailed Implementation
[0021] Example 1: Synthesis of (Mn1Ce2)MIL-100 Catalyst and H2O2 Synthesis The synthesis process of the (Mn1Ce2)MIL-100 catalyst includes: (a) Dissolving 6 mmol of Mn(NO3)2·4H2O and 6 mmol of trimesic acid in 40 mL of methanol, stirring magnetically (1000 rpm) for 30 min to form a transparent solution, transferring it to a 100 mL reactor, and reacting at 120 °C for 3 h. After the reaction, the product was washed three times with anhydrous ethanol and dried overnight under vacuum to finally obtain the MIL-100(Mn) sample. (b) Synthesis of MIL-100(Mn1Ce2): The MIL-100(Mn) obtained in (a) was redispersed in a methanol solution, followed by the addition of 4 mmol of cerium nitrate hexahydrate (Ce(NO3)3·6H2O), and mixed thoroughly under stirring. The resulting mixed solution was transferred to a high-pressure reactor and reacted at 120 °C for 3 h. After the reaction was complete, the product was washed three times with anhydrous ethanol and dried overnight under vacuum to finally obtain the MIL-100 (Mn1Ce2) sample. The synthesis process is detailed in the appendix. Figure 1 (Mn1Ce2)MIL-100 exhibits regular octahedral crystal characteristics (see attached). Figure 2 No structural collapse or phase transition was observed. Energy dispersive spectroscopy (EDS) analysis showed that Ce was uniformly distributed within the particles (see attached image). Figure 3 No phase separation or regional enrichment was observed, achieving bimetallic synergistic doping. The sample has a BET specific surface area of 560 m². 2 / g, with a peak pore size distribution of 0.6-0.8nm.
[0022] Performance testing of photocatalytic H2O2 generation: 5 mg of photocatalyst was added to 45 mL of deionized water and placed in a 100 mL quartz beaker. The mixture was first sonicated in the dark for 30 min to promote uniform dispersion. Then, ozone gas was bubbled in for 10 min to allow the catalyst surface to fully adsorb ozone, providing an active oxygen source for subsequent reactions. Afterward, the system was irradiated with a 300 W xenon lamp, and a long-pass filter with λ > 420 nm was used to simulate visible light irradiation conditions. The photocatalytic reaction lasted for different durations. The amount of H2O2 generated in the product was calculated. The average H2O2 generation rate of MIL-100 (Mn1Ce2) reached 1403 μmol·g. -1 ·h -1It was significantly higher than the 474 μmol·g of the MIL-100(Mn) sample. -1 ·h -1 The increase reached 196% (see attached) Figure 4 Throughout the 15-hour visible light irradiation process, H2O2 production maintained a linear growth trend without plateauing or reaction stagnation, ultimately achieving a cumulative yield of 21035 μmol, a 6.1-fold increase compared to MIL-100 (Mn). After 5 cycles, the activity remained at 87.1% (see attached image). Figure 5 This solves the problems of low oxygen mass transfer efficiency and the need for sacrificial agents in traditional photocatalytic systems.
[0023] Example 2: (Mn1Ce 0.2 MIL-100 catalyst synthesis and H2O2 synthesis: The synthesis process is the same as in Example 1, except that 0.4 mmol of cerium nitrate hexahydrate (Ce(NO3)3·6H2O) is added. (Mn1Ce 0.2 MIL-100 exhibits a typical octahedral crystal morphology (see attached image). Figure 6 The specific surface area of BET is 600m². 2 ·g -1 The pore size is mainly concentrated in the range of 0-1 nm, belonging to a typical microporous structure. The average H2O2 formation rate of this sample is 664 μmol·g. -1 ·h -1 .
[0024] Example 3: (Mn1Ce 2.2 MIL-100 catalyst synthesis and H2O2 synthesis: The synthesis process is the same as in Example 1, except that 4.4 mmol of cerium nitrate hexahydrate (Ce(NO3)3·6H2O) is added. (Mn1Ce 2.2 MIL-100 exhibits a typical octahedral crystal morphology. Its BET specific surface area is 550 m² / g. 2 ·g -1 The pore size is mainly concentrated in the range of 0.6-0.8 nm. The average H2O2 formation rate of this sample is 1300 μmol·g. -1 ·h -1 .
[0025] Example 4: Synthesis of MIL-100(Mn) Sample H2O2 Synthesis: The synthesis process was the same as in Example 1, except that cerium nitrate hexahydrate (Ce(NO3)3·6H2O) was not added. MIL-100(Mn) exhibits a typical octahedral crystal morphology. The BET specific surface area is 892 m². 2 ·g -1 The pore size is mainly concentrated in the range of 0-0.1 nm. The average H2O2 formation rate of this sample is 474 μmol·g. -1 ·h-1 .
[0026] Example 5: Synthesis of MIL-100 (Ce): 6 mmol of cerium nitrate hexahydrate (Ce(NO3)3·6H2O) was dissolved in an appropriate amount of methanol, followed by the addition of trimesic acid (H3BTC). The reaction was carried out under continuous stirring until the system became a transparent solution. The resulting mixed solution was transferred to a high-pressure reactor and reacted at 120°C for 3 h. After the reaction, the product was washed three times with anhydrous ethanol and dried overnight under vacuum to finally obtain the MIL-100 (Ce) sample. The BET specific surface area was 37 m². 2 ·g -1 The sample lacks an effective microporous structure, with pore sizes widely distributed in the >10 nm region, exhibiting a non-uniform mesoporous structure. MIL-100(Ce), on the other hand, displays a rod-like stacked morphology similar to the Ln-BTC topology. The average H2O2 formation rate of this sample is 314 μmol·g⁻¹. -1 ·h -1 .
Claims
1. A bimetallic MOF catalyst with the chemical formula (MnCe)MIL-100, the synthesis process of which includes: (a) MIL-100(Mn) was prepared by dissolving Mn(NO3)2·4H2O and trimesic acid in methanol at a 1:1 molar ratio and reacting hydrothermally at 120°C for 3 h; (b) MIL-100(Mn) and Ce(NO3)3·6H2O were mixed in methanol at a certain Mn:Ce molar ratio and reacted a second time at 120°C for 3 h. This bimetallic MOF catalyst can be used for the photocatalytic synthesis of H2O2 from ozone.
2. In claim 1, the molar ratio of Mn to Ce is 1:(0.2-2.2).
3. The bimetallic MOF catalyst in claim 1 has a BET specific surface area of 550 ± 50 m². 2 / g, with a peak pore size distribution of 0.6-0.8nm.
4. The bimetallic MOF catalyst of claim 1 can synthesize H2O2 via ozone photocatalysis, characterized in that: With an ozone concentration of 700±50 ppb, a bimetallic MOF catalyst suspension (0.11 g / L) was placed in a quartz photoreactor, and a 300W xenon lamp with a wavelength of 420 nm and a light intensity of 100 mW / cm² was used. 2 Under these conditions, a photocatalytic reaction takes place.
5. The synthesis method as described in claim 4, characterized in that... step: (1) The catalyst was dispersed in deionized water and sonicated in the dark for 30 min; (2) Introduce ozone for 10 minutes until adsorption saturation.