Porphyrin-Fe < 3 + > complex nanowire as well as preparation method and application thereof

Abstract

The invention discloses a porphyrin-Fe < 3 + > complex nanowire as well as a preparation method and application thereof. The nanowire is prepared by the following steps: dissolving FeCl3. 6H2O and 5, 10, 15, 20-tetra (4-carboxyl phenyl) porphin into a mixed solvent of absolute ethyl alcohol and N, N-dimethylformamide, and carrying out ultrasonic treatment to obtain a mixed solution; performing solvothermal reaction on the mixed solution in a high-pressure reaction kettle, naturally cooling to room temperature after the reaction is finished, and performing centrifugal separation to obtain a solid product, namely the porphyrin-Fe < 3 + > complex nanowire. The porphyrin-Fe < 3 + > complex nanowire provided by the invention has the advantages of large specific surface area, better conductivity and rich carboxyl groups, monodisperse metal nodes and delocalized macrocyclic conjugated structures on the surface, and can be used for photocatalytic degradation of rhodamine 6G dye.

Description

Technical Field

[0001] This invention relates to the field of porphyrin nanomaterial manufacturing technology, and particularly to a porphyrin-Fe 3+ Complex nanowires, their preparation methods, and applications. Background Technology

[0002] Porphyrins are common planar molecules with rigid, large π-conjugated structures, possessing unique photoelectric, adsorption, and catalytic properties, structural stability, and abundant functional groups. They are widely used in sensors, luminescence, catalysis, biology, and nanodevices. Examples include photoreaction centers in photosynthesis, redox catalysis in biomolecules, and oxygen transport centers in vitamin B12.

[0003] In nature, porphyrins function by forming assemblies through regular stacking. In the field of photocatalysis, researchers often mimic these natural porphyrin assemblies. Studies have found that porphyrins primarily exhibit regular stacking patterns, such as "side-by-side" and "head-to-head." This ordered stacking structure promotes the delocalization of conjugated electrons, facilitating the separation of electrons and holes and enhancing photocatalytic efficiency. Currently, common porphyrin assembly methods rely heavily on external assistance, such as introducing non-covalently interacting templates or performing complex chemical modifications to the porphyrin molecules. These methods are not only cumbersome but also difficult to precisely control the assembly process. Due to the complexity of intermolecular interactions in porphyrins (such as π-π stacking and metal coordination), these methods easily lead to uncontrollable assembly pathways. The final products are often thermodynamically stable nanoparticles or amorphous aggregates with varying morphologies, rather than highly efficient photocatalytic materials with long-range ordered structures. This morphological uncertainty directly results in unpredictable and unstable photoelectric properties. Nanowires are one-dimensional nanomaterials with excellent charge transport properties. Electrons (e⁻) and holes (h⁺) generated by light or electrical excitation need to be effectively separated and transferred to the surface to participate in reactions. In zero-dimensional nanoparticles, charge jumps between different particles, resulting in high resistance and easy recombination failure. However, how to achieve the controllable self-assembly of porphyrin molecules with metal ions (such as Fe³⁺) without relying on complex templates or pre-modification, and directly construct porphyrin-based metal complex nanowires with regular structure and uniform size, remains a major challenge in the field.

[0004] Therefore, it is necessary to develop a novel, highly efficient, and controllable porphyrin-Fe 3+ The preparation method of complex nanowires is particularly important.

[0005] Therefore, this invention is proposed to solve the above-mentioned technical problems. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing porphyrin-Fe3+ complex nanowires, comprising the following steps:

[0007] S1. Iron source and porphyrin-based organic compound are added to a mixed solvent and then ultrasonically treated to obtain a mixed solution;

[0008] S2. The mixed solution obtained in S1 is subjected to a solvothermal reaction. After the reaction is completed, it is naturally cooled to room temperature and centrifuged to obtain a solid product.

[0009] S3. Wash and dry the solid product to obtain porphyrin-Fe 3+ Complex nanowires.

[0010] Preferably, in step S1, the iron source is ferric chloride hexahydrate.

[0011] Preferably, in step S1, the molar ratio of the iron source to the porphyrin-type organic compound is (5~10):1.

[0012] Preferably, in step S1, the mixed solvent is N,N-dimethylformamide and anhydrous ethanol mixed at a volume ratio of 1:(2~4).

[0013] Preferably, in step S1, the ultrasonic power is 100~150W, the ultrasonic temperature is 30℃, and the ultrasonic time is 20~40min.

[0014] Preferably, in step S2, the reaction temperature of the solvothermal reaction is 80~120℃, and the reaction time is 24~48h.

[0015] Preferably, in step S2, the centrifugal separation speed is 8000~10000 rpm.

[0016] Preferably, in step S1, the volume of the mixed solvent added to each 0.01~0.05 mmol of porphyrin organic compound is 12~20 mL. Specifically, the porphyrin organic compound is 5,10,15,20-tetra(4-carboxyphenyl)porphyrin, abbreviated as TCPP.

[0017] The present invention also provides a porphyrin-Fe prepared by the above preparation method. 3+ Complex nanowires. Another object of the present invention is to provide the above-mentioned porphyrin-Fe 3+ Application of complex nanowires in the photocatalytic degradation of rhodamine 6G.

[0018] The beneficial effects of this invention are:

[0019] The present invention discloses a method for preparing porphyrin-Fe³⁺ complex nanowires, which directly obtains porphyrin-Fe³⁺ complex nanowires (TCPP-FeNWs) with regular morphology and uniform size through a one-step solvothermal reaction to coordinate self-assemble TCPP with Fe³⁺. This preparation method does not require the introduction of additional templates, surfactants or pre-modification of ligands, has a short process flow, is simple to operate, and uses readily available raw materials at low cost.

[0020] Furthermore, the one-dimensional continuous structure of the nanowires prepared in this invention provides directional transport pathways for photogenerated electrons (e⁻) and holes (h⁺), which can greatly suppress charge recombination and improve charge utilization. This is verified by its highly efficient photocatalytic degradation performance, achieving a degradation rate of over 98% for Rhodamine 6G. Attached Figure Description

[0021] Figure 1 Transmission electron microscope image of the product prepared in Example 3;

[0022] Figure 2 Transmission electron microscope image of the product prepared for Comparative Example 1.

[0023] Figure 3 Transmission electron microscope image of the product prepared for Comparative Example 2;

[0024] Figure 4 Example 3: Porphyrin-Fe 3+ UV-Vis absorption spectra of complex nanowires;

[0025] Figure 5 The images show the photocatalytic degradation effect of Rhodamine 6G by the products of Examples 1-3 and Comparative Examples 1-2. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1

[0028] This embodiment contains a porphyrin-Fe 3+ The preparation method of complex nanowires includes the following steps:

[0029] S1. Dissolve 0.25 mmol of FeCl3·6H2O and 0.05 mmol of TCPP in a mixed solvent of 4 mL DMF and 16 mL anhydrous ethanol, and sonicate at 150 W for 40 min to obtain a mixed solution.

[0030] S2. The mixed solution prepared in step S1 was subjected to a solvothermal reaction in a stainless steel high-pressure reactor lined with 20 mL of tetrafluoroethylene. The reaction temperature was 120℃ and the reaction time was 24 h. After the reaction was completed, the mixture was naturally cooled to room temperature and then centrifuged at 10000 rpm to obtain a solid product.

[0031] S3. The solid product was washed with DMF and anhydrous ethanol respectively, and then dried under vacuum to obtain the product.

[0032] Example 2

[0033] This embodiment contains a porphyrin-Fe 3+ The preparation method of complex nanowires includes the following steps:

[0034] S1. Dissolve 0.15 mmol of FeCl3·6H2O and 0.02 mmol of TCPP in a mixed solvent of 4 mL DMF and 10 mL anhydrous ethanol, and sonicate at 100 W for 20 min to obtain a mixed solution.

[0035] S2. The mixed solution prepared in step S1 is subjected to a solvothermal reaction in a stainless steel high-pressure reactor lined with 20 mL of tetrafluoroethylene. The reaction temperature is 100℃ and the reaction time is 30 h. After the reaction is completed, the mixture is naturally cooled to room temperature and then centrifuged at 8000 rpm to obtain a solid product.

[0036] S3. The solid product was washed with DMF and anhydrous ethanol respectively, and then dried under vacuum to obtain the product.

[0037] Example 3

[0038] This embodiment contains a porphyrin-Fe 3+ The preparation method of complex nanowires includes the following steps:

[0039] S1. Dissolve 0.10 mmol of FeCl3·6H2O and 0.01 mmol of TCPP in a mixed solvent of 4 mL DMF and 8 mL anhydrous ethanol, and sonicate at 120 W for 30 min to obtain a mixed solution.

[0040] S2. The mixed solution prepared in step S1 was subjected to a solvothermal reaction in a stainless steel high-pressure reactor lined with 20 mL of tetrafluoroethylene. The reaction temperature was 80℃ and the reaction time was 48 h. After the reaction was completed, the mixture was naturally cooled to room temperature and then centrifuged at 9000 rpm to obtain the solid product.

[0041] S3. The solid product was washed with DMF and anhydrous ethanol respectively, and then dried under vacuum to obtain the product.

[0042] Comparative Example 1

[0043] The difference between this comparative example and Example 3 is that the solvent used in step S1 is a single 12ml LDM solvent.

[0044] Comparative Example 2

[0045] The difference between this comparative example and Example 3 is that the reaction temperature in step S2 is 170°C.

[0046] Experimental verification 1

[0047] The morphology of the products prepared in Example 3 and Comparative Examples 1 and 2 was characterized using a JEM-F200(HR) transmission electron microscope (see results). Figures 1-3 );from Figure 1 It can be seen that the prepared product has a uniform morphology, is a regular nanowire, and has a size of about 15 μm. Figure 2 The irregular and disordered structure is due to the fact that ethanol is less polar than DMF. Its addition reduces the solubility of TCPP in the solvent. In a solvothermal reaction, lower solubility increases supersaturation and promotes nucleation. More importantly, ethanol molecules may adsorb onto specific crystal faces through hydrogen bonding and other interactions, inhibiting the growth of those crystal faces and thus guiding the crystal to grow one-dimensionally along a specific direction, forming a linear structure. Figure 3 They are in particle form because higher temperatures significantly increase the reaction rate and molecular kinetic energy, resulting in a very fast nucleation rate and the instantaneous generation of a large number of crystal nuclei. These crystal nuclei grow rapidly but isotropically at high temperatures, eventually forming nanoparticles.

[0048] Experimental Verification 2

[0049] like Figure 4 As shown, the spectroscopic properties of the product prepared in Example 3 were characterized using a Shimadzu UV-1800 ultraviolet-visible absorption spectrometer. Figure 4 As can be seen, compared to the absorption peaks of TCPP near 414.5 nm, 517.0 nm, 554.5 nm, 581.0 nm, and 635.0 nm, the prepared porphyrin-Fe 3+ The absorption peaks of the complex all showed significant broadening and red shift, indicating that the porphyrin-Fe... 3+ Formation of complex nanowires.

[0050] Experimental verification 3

[0051] The photocatalytic degradation performance of the products prepared in Examples 1-3 and Comparative Examples 1-2 on the typical dye Rhodamine 6G was specifically investigated.

[0052] 2.0 mg of the products prepared in Examples 1-3 and Comparative Examples 1-2 were weighed and ultrasonically dispersed in a 40 mL Rh6G (A0=0.819) solution. Adsorption was performed in the dark for 20 min, followed by 40 min of visible light irradiation. The concentration of the Rh6G solution was monitored with irradiation time using a UV-Vis spectrophotometer; the 20 min dark adsorption was to eliminate interference from physical adsorption.

[0053] Porphyrin-Fe prepared in Example 3 3+ Monitoring results of complex nanowires are as follows Figure 5 As shown, the prepared porphyrin-Fe 3+ The complex nanowires achieved a 99% degradation efficiency of Rh6G solution (concentration, volume) under visible light irradiation, indicating excellent photocatalytic degradation performance of Rh6G dye. Specific data are shown in Table 1 and... Figure 5 As shown.

[0054] Table 1

[0055] Group Degradation rate (%) Example 1 98.5 Example 2 98 Example 3 99 Comparative Example 1 82 Comparative Example 2 90

[0056] As can be seen from the table, the porphyrin-Fe3+ complex nanowires prepared in the examples have excellent photocatalytic degradation ability for Rhodamine 6G. This is because the TCPP molecule (porphyrin derivative) can absorb light energy under visible light irradiation due to its large π-bond structure. Electrons transition from the ground state to the excited state, generating high-energy electrons (e-) and holes (h+). Fe3⁺ is converted into Fe²⁺ by accepting electrons, participating in the oxygen reduction cycle and enhancing the generation of superoxide radicals (·O2⁻). The excited-state electrons (e-) can be transferred to oxygen (O2) adsorbed on the material surface to generate superoxide radicals (•O2-). At the same time, the holes (h+) can oxidize water (H2O) or hydroxide ions (OH⁻) to generate hydroxyl radicals (•OH). These reactive oxygen species (ROS) possess extremely strong oxidizing power, capable of progressively oxidizing and decomposing organic dye molecules such as Rhodamine 6G into smaller molecules, ultimately transforming them into CO2 and H2O. The nanowire structures prepared in the examples are interwoven into a network, with a large specific surface area, effectively capturing and scattering visible light multiple times, enhancing light absorption. Furthermore, the one-dimensional structure provides a directional transport channel for photogenerated electrons, allowing electrons to rapidly migrate to the surface and participate in reactions. Although the nanoparticles in Comparative Example 2 have poor charge transport, their high specific surface area provides more active sites, resulting in a higher degradation rate than the disordered structure of Comparative Example 1, but not as high as the structure-optimized examples. In the disordered and discontinuous structure of Comparative Example 1, the electron transport path is tortuous and faces high resistance, making it easy for electrons to recombine with holes during migration. Additionally, the bulk structure causes light to be reflected or penetrated, resulting in low light utilization efficiency. The above descriptions are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A porphyrin-Fe 3+ The method for preparing complex nanowires is characterized by, Includes the following steps: S1. Iron source and porphyrin-based organic compound are added to a mixed solvent and then ultrasonically treated to obtain a mixed solution; S2. The mixed solution obtained in S1 is subjected to a solvothermal reaction. After the reaction is completed, it is naturally cooled to room temperature and centrifuged to obtain a solid product. S3. Wash and dry the solid product to obtain porphyrin-Fe 3+ Complex nanowires.

2. The preparation method according to claim 1, characterized in that, In step S1, the iron source is ferric chloride hexahydrate.

3. The preparation method according to claim 1, characterized in that, In step S1, the molar ratio of the iron source to the porphyrin-based organic compound is 5~10:

1.

4. The preparation method according to claim 1, characterized in that, In step S1, the mixed solvent is N,N-dimethylformamide and anhydrous ethanol mixed at a volume ratio of 1:2~4.

5. The preparation method according to claim 1, characterized in that, In step S1, the ultrasonic power is 100~150W, the ultrasonic temperature is 30℃, and the ultrasonic time is 20~40min.

6. The preparation method according to claim 1, characterized in that, In step S2, the reaction temperature of the solvothermal reaction is 80~120℃, and the reaction time is 24~48h.

7. The preparation method according to claim 1, characterized in that, In step S2, the centrifugal separation speed is 8000~10000 rpm.

8. The preparation method according to claim 1, characterized in that, In step S1, the volume of the mixed solvent added to each 0.01~0.05 mmol of porphyrin organic compound is 12~20 mL.

9. A porphyrin-Fe prepared by the preparation method according to any one of claims 1 to 8 3+ Complex nanowires.

10. A porphyrin-Fe as described in claim 9 3+ Application of complex nanowires in the photocatalytic degradation of rhodamine 6G.

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