Preparation method of MOF-on-MOF nano material for growing CoFePBA on MOF-274

Abstract

The invention discloses a preparation method of an MOF-on-MOF nano material for growing CoFePBA on MOF-274. According to the method, Co-based MOF-274 with inherent rod-like morphology and high-activity Prussian blue analogue (CoFePBA) nano particles are effectively subjected to interface heterogeneous integration, and the CoFePBA nano material is prepared. The hybrid composite material which is regular in morphology, high in specific surface area, high in grading porosity and rich in CoFe bimetallic synergistic active sites is prepared, the multifunctionality and the synergistic effect of the material are remarkably improved, and the problems that a single-function material is limited in active sites and insufficient in integration performance in specific application are solved.

Description

Technical Field

[0001] This invention relates to the field of novel functional composite material synthesis technology, specifically to a method for preparing MOF-on-MOF nanomaterials with CoFePBA grown on MOF-274. Background Technology

[0002] Metal-organic frameworks (MOFs), with their tunable structures, abundant active sites, and low precursor costs, are widely recognized as an important class of porous functional materials, exhibiting enormous application potential in diverse fields such as catalysis, adsorption, and energy storage. However, the inherent limitations of single MOF materials, particularly their extremely poor intrinsic electronic conductivity and insufficient thermal / water stability in harsh environments such as aqueous electrolytes, severely restrict their practical application feasibility. These challenges often stem from the isolated nature of the crystal building blocks, making it difficult to achieve significant performance improvements through simple bulk phase modification alone. Therefore, to enable MOFs to achieve superior and durable functional performance, a shift towards interface engineering and the construction of hybrid hierarchical structures is urgently needed.

[0003] To overcome the aforementioned limitations, current technological paradigms prioritize the development of MOF-based heterostructures, particularly MOF-on-MOF structures. This approach integrates second-generation MOF or MOF-like coordination polymer layers onto primary MOF crystals to design synergistic active sites and hierarchical porosity. Nevertheless, existing synthetic methods for MOF-on-MOF and similar heterostructures still face significant technical challenges. Specifically, achieving epitaxial or directional growth remains difficult, often resulting in uneven shell coverage, which compromises the overall uniformity and batch stability of the composite material. Furthermore, many preparation routes involve complex, multi-step processes or require harsh reaction conditions, making atomic / nanoscale precise control of interfacial bonding difficult. This complexity leads to low product yields and poses a major obstacle to large-scale industrial production. Therefore, there is an urgent need in the field for a synthetic strategy that is simple to operate, operates under mild conditions, and achieves high interfacial controllability to accelerate the development and application of high-performance MOF-based hierarchical composites. Summary of the Invention

[0004] The purpose of this invention is to solve the problems of difficult interface control, poor morphological uniformity, and insufficient synergistic effect of composite material properties in the synthesis of MOF-on-MOF heterostructures in the prior art, and to provide a method for preparing MOF-on-MOF nanomaterials with CoFePBA grown on MOF-274.

[0005] The technical solution adopted in this invention is as follows:

[0006] A method for preparing MOF-on-MOF nanomaterials with CoFePBA grown on MOF-274 includes the following steps:

[0007] Preparation of S1 and MOF-274

[0008] Co(CH3COO)2·4H2O, H4dobpdc, DMF, MeOH, H2O, and THF were mixed and heated for 2 hours, then reacted at 100 °C for 1 day to obtain MOF-274.

[0009] Preparation of S2 and MOF-274@PBA

[0010] MOF-274, K3[Fe(CN)6], and H2O in S1 were mixed and reacted at 60 °C for 30 min to obtain MOF-274@PBA.

[0011] Preferably, in step S1, 0.12 mmol and 30 mg Co(CH3COO)2·4H2O are dissolved in a mixed solution of 1.5 mL DMF, 1.5 mL H2O and 1.5 mL MeOH to prepare mixture A; 0.12 mmol and 33 mg H4dobpdc are dissolved in a mixed solution of 1.5 mL DMF, 1.5 mL H2O and 1.5 mL THF to prepare mixture B; mixture A and mixture B are sequentially added to a 25 mL reaction vessel for reaction.

[0012] Preferably, in step S1, after the obtained MOF-274 is cooled to room temperature, the product is collected, centrifuged, washed three times with ethanol, and the filtered solid is dried overnight under vacuum at 85°C to obtain pure MOF-274.

[0013] Preferably, in S1, MOF-274 is pink, has a needle-like morphology, and a BET surface area of ​​[missing information]. .

[0014] Preferably, in step S2, 30 mg MOF-274 and 16 mg K3[Fe(CN)6] are mixed and added to a 35 mL pressure-resistant tube, and then 10 mL H2O is added to carry out the reaction.

[0015] Preferably, in step S2, after the prepared MOF-274@PBA is naturally cooled to room temperature, the product is collected, centrifuged, washed three times with ethanol, and the filtered solid is dried at 85°C overnight to obtain purified MOF-274@PBA.

[0016] Preferably, in S2, the MOF-on-MOF is grayish-blue, and the BET surface area is [missing information]. .

[0017] The method of this invention utilizes Co 2+ MOF-274, as a first-generation MOF substrate, possesses a regular needle-like morphology and provides abundant open Co. 2+ Active sites. These sites can effectively anchor and induce in-situ coordination deposition of Prussian blue analogue (PBA) nanocomponents on the surface of MOF-like materials, making them ideal precursors for hierarchical MOF-based composites. This synthesis was achieved under controlled, mild conditions, yielding a core-shell heterostructure with a tightly integrated MOF-274 core and PBA nanolayers. This structure effectively combines the high surface area of ​​MOF with the excellent conductivity of PBA, achieving a CoFe bimetallic synergy that significantly modulates surface electron distribution and enhances the density of active sites. This method exhibits good reproducibility, high yield, excellent morphology preservation, and high interfacial integration.

[0018] The beneficial effects of this invention are as follows:

[0019] 1. This invention provides a mild in-situ interfacial synthesis method for MOF-274@PBA hybrid composite materials of MOF-on-MOF type. The composite material prepared by this invention successfully achieves tight heterogeneous integration of MOF-274 and MOF-like PBA components, and has advantages such as regular morphology, high specific surface area, high hierarchical porosity, and abundant CoFe bimetallic synergistic active sites.

[0020] 2. The method of the present invention is simple, the conditions are mild and controllable, it has good repeatability and high yield, and it can be used for large-scale production. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the process for preparing needle-shaped MOF-274@PBA MOF-on-MOF nanomaterials according to the present invention.

[0022] Figure 2 Scanning electron microscope image of MOF-274;

[0023] Figure 3 Scanning electron microscope image of MOF-274@PBA;

[0024] Figure 4 X-ray powder diffraction pattern of MOF-274;

[0025] Figure 5 X-ray powder diffraction pattern of MOF-274@PBA

[0026] Figure 6 Powder images of MOF-274 and MOF-274@PBA;

[0027] Figure 7The nitrogen adsorption-desorption curves and pore size distribution PSD curves for MOF-274 are shown.

[0028] Figure 8 The nitrogen adsorption-desorption curve and pore size distribution PSD curve of MOF-274@PBA are shown. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0030] Example 1

[0031] (1) Mixture A was prepared by dissolving Co(CH3COO)2·4H2O (0.12 mmol, 30 mg) in a mixed solution of DMF (1.5 mL), H2O (1.5 mL), and MeOH (1.5 mL); mixture B was prepared by dissolving H4dobpdc (0.12 mmol, 33 mg) in a mixed solution of DMF (1.5 mL), H2O (1.5 mL), and THF (1.5 mL). Mixtures A and B were then added sequentially to a 25 mL reaction vessel. The heating time was adjusted to 2 h, and the reaction was carried out in a 100 °C oven for 1 day. After cooling to room temperature, the product was collected, centrifuged, washed three times with ethanol, and the filtered solid was dried overnight under vacuum at 85 °C to obtain high-yield pure MOF-274.

[0032] (2) A mixture of MOF-274 (30 mg) and K3[Fe(CN)6] (16 mg) was added to a 35 mL pressure-resistant tube. Then 10 mL of H2O was added and the mixture was placed in a magnetic stirrer and reacted at 60 °C for 30 min. After naturally cooling to room temperature, the product was collected, centrifuged, washed three times with ethanol, and the filtered solid was dried at 85 °C overnight to obtain MOF-274@PBA.

[0033] like Figure 1 The diagram shows the preparation process of MOF-274@PBA MOF-on-MOF nanomaterials using MOF-274 precursor as a stepwise precursor according to the present invention.

[0034] like Figure 2 This indicates that the synthesized MOF-274 is a needle-like powder nanomaterial.

[0035] like Figure 3 This indicates that PBA nanoparticles were successfully grown on the surface of MOF-274 after MOF-on-MOF synthesis.

[0036] like Figure 4 The X-ray powder diffraction pattern shows that the MOF matches the simulated PXRD pattern, with a value at 8.16° ( The sharp diffraction peaks of the crystal planes verified the high purity and crystallinity of the synthesized MOF material.

[0037] like Figure 5 The X-ray powder diffraction pattern shows that the diffraction peaks at 8.16°, 17.51°, 24.86°, and 35.45° correspond to the diffraction peaks of MOF-274, respectively. The (200), (220), and (400) crystal planes of CoFePBA demonstrate the successful preparation of MOF-on-MOF.

[0038] like Figure 6 The color of MOF-274 changed from pink to grayish-blue when synthesized into MOF-274@PBA, demonstrating the successful synthesis of MOF-on-MOF nanomaterials.

[0039] like Figure 7 As shown in the nitrogen adsorption-desorption curve and pore size distribution PSD curve, MOF-274 exhibits a type I adsorption curve, with a BET surface area of ​​[missing information]. Its pore size distribution (PSD) has a wide distribution in the 2 nm region, proving that its MOF is a microporous MOF.

[0040] like Figure 8 As shown in the nitrogen adsorption-desorption curve and pore size distribution PSD curve, MOF-274@PBA exhibits a type IV adsorption curve, with a BET surface area of ​​[missing information]. This may be attributed to the growth of PBA on the surface of MOF-274, which occupies the cavity sites and reduces the BET surface area. Its pore size distribution (PSD) is distributed in the region within 2 nm and around 10 nm, proving that its MOF has micropores and mesopores.

[0041] In summary, the method of this invention effectively integrates Co-based MOF-274 with an inherent rod-like morphology with highly active Prussian blue analog (CoFePBA) nanoparticles at the interface, significantly improving the multifunctionality and synergistic effect of the material. The prepared composite material successfully achieves tight heterogeneous integration of MOF-274 and MOF-like PBA components, and has advantages such as regular morphology, high specific surface area, high hierarchical porosity, and abundant CoFe bimetallic synergistic active sites.

[0042] The specification and drawings of this invention are intended to be illustrative rather than restrictive. Based on this invention, those skilled in the art can make substitutions and modifications to some of the technical features without creative effort, and all such modifications are within the scope of protection of this invention.

Claims

1. A method for preparing MOF-on-MOF nanomaterials with CoFePBA grown on MOF-274, characterized in that, Includes the following steps: Preparation of S1 and MOF-274 Co(CH3COO)2·4H2O, H4dobpdc, DMF, MeOH, H2O, and THF were mixed and heated for 2 hours, then reacted at 100 °C for 1 day to obtain MOF-274. Preparation of S2 and MOF-274@PBA MOF-274, K3[Fe(CN)6], and H2O in S1 were mixed and reacted at 60 °C for 30 min to obtain MOF-274@PBA.

2. The preparation method according to claim 1, characterized in that, In step S1, 0.12 mmol and 30 mg Co(CH3COO)2·4H2O are dissolved in a mixed solution of 1.5 mL DMF, 1.5 mL H2O and 1.5 mL MeOH to prepare mixture A; 0.12 mmol and 33 mg H4dobpdc are dissolved in a mixed solution of 1.5 mL DMF, 1.5 mL H2O and 1.5 mL THF to prepare mixture B; mixture A and mixture B are added sequentially to a 25 mL reaction vessel for reaction.

3. The preparation method according to claim 1, characterized in that, In step S1, after the prepared MOF-274 is cooled to room temperature, the product is collected, centrifuged, washed three times with ethanol, and the filtered solid is dried overnight under vacuum at 85°C to obtain pure MOF-274.

4. The preparation method according to claim 1, characterized in that, The MOF-274 in S1 is pink, needle-shaped, and has a BET surface area of ​​[missing information]. .

5. The preparation method according to claim 1, characterized in that, In step S2, 30 mg MOF-274 and 16 mg K3[Fe(CN)6] are mixed and added to a 35 mL pressure-resistant tube, and then 10 mL H2O is added to carry out the reaction.

6. The preparation method according to claim 1, characterized in that, In step S2, after the prepared MOF-274@PBA is naturally cooled to room temperature, the product is collected, centrifuged, washed three times with ethanol, and the filtered solid is dried at 85°C overnight to obtain purified MOF-274@PBA.

7. The preparation method according to claim 1, characterized in that, In S2, the MOF-on-MOF is grayish-blue, and the BET surface area is... .

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