A metal phthalocyanine / cobalt hydroxide knitted hexagonal micron sheet and its preparation method

Abstract

The present invention belongs to the technical field of functional materials, and specifically relates to a metal phthalocyanine / cobalt hydroxide knitted hexagonal micron sheet and a preparation method thereof. The preparation method comprises the following steps: ultrasonically dissolving a cobalt salt in deionized water to obtain a cobalt salt solution, further adding a metal phthalocyanine compound to the solution, and ultrasonically dispersing to obtain a mixed solution; placing ammonium bicarbonate or ammonium carbonate at the bottom of a reaction device with a porous sieve plate, placing the mixed solution in a container and placing it on the porous sieve plate to carry out a bionic mineralization synthesis reaction; after the reaction is completed, filtering the solution in the container, centrifugally washing the filtered solid, and drying to obtain a metal phthalocyanine / cobalt hydroxide knitted hexagonal micron sheet. The present invention prepares metal phthalocyanine / cobalt hydroxide knitted hexagonal micron sheets through a simple bionic mineralization synthesis strategy. Its special structure can fully expose the reaction active sites, shorten the ion diffusion path, strengthen the ion diffusion driving force, and improve the adsorption kinetics and catalytic performance.

Description

Technical Field

[0001] The invention belongs to the technical field of functional materials, and particularly relates to a metal phthalocyanine / cobalt hydroxide knitted hexagonal micron sheet and a preparation method thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Due to their advantages such as wide availability, low price and environmental friendliness, transition metal hydroxides have been extensively studied in the fields of energy, catalysis and environment. Cobalt hydroxide, as a typical transition metal hydroxide, has attracted the attention of researchers due to its high Faradaic reaction activity and catalytic performance. A large amount of research data shows that the structure of the material greatly affects its performance. Therefore, the development of simple and controllable preparation methods to synthesize and regulate the structure of cobalt hydroxide or its composite materials is crucial for their widespread application.

[0004] Phthalocyanines are macrocyclic conjugated complexes with a 16-center, 18π-electron aromatic conjugated system consisting of 8 nitrogen atoms and 8 carbon atoms. They exhibit excellent photo-, thermal-, and chemical stability, outstanding optical and electrical properties, good absorption in the visible light region, and adjustable molecular structure. Their unique two-dimensional conjugated structure, high photo- and thermal stability, and designability of their molecular structure have led to their widespread application in optical, electrical, and catalytic fields. Furthermore, the phthalocyanine ring contains a cavity that can accommodate metal elements such as iron, copper, cobalt, aluminum, nickel, calcium, sodium, magnesium, and zinc, forming metal complexes. By varying the metal ions and substituents, phthalocyanines and metallophthalocyanine compounds with various substituents can be designed and synthesized. In prior art composites of phthalocyanine and cobalt hydroxide, phthalocyanine serves as an active site dispersed within the cobalt hydroxide support. However, whether phthalocyanine can influence the structure and properties of the hydroxide during synthesis remains unknown.

[0005] Biomineralization is a common phenomenon in nature. It refers to the process by which organisms generate inorganic minerals through the regulation of biomacromolecules. It is a complex, multi-layered process with numerous influencing factors, but it has attracted widespread research interest due to its unique advantages in constructing complex micro- and nanostructures. Inspired by natural biomineralization, biomimetic mineralization synthesis strategies have rapidly developed in recent years. Using biomimetic mineralization synthesis strategies, it is hoped that structural properties such as material morphology and crystal form can be controlled to synthesize complex, multi-layered micro- and nanostructures. However, the structural properties of materials are influenced by multiple factors, and a specific structure does not necessarily improve material performance. How to use biomimetic mineralization synthesis strategies to precisely control material structure and beneficially influence material performance remains to be studied. Summary of the Invention

[0006] To address the deficiencies of the prior art, the present invention provides a metal phthalocyanine / cobalt hydroxide knitted hexagonal microsheet and a method for preparing the same. The present invention uses ammonium bicarbonate or ammonium carbonate as a precipitant and a solution containing a dispersed metal phthalocyanine compound and a cobalt salt as a reaction solution to prepare the metal phthalocyanine / cobalt hydroxide knitted hexagonal microsheet via a simple biomimetic mineralization synthesis strategy. The unique structure of the metal phthalocyanine / cobalt hydroxide knitted hexagonal microsheet fully exposes reactive sites, shortens the ion diffusion path, enhances the driving force for ion diffusion, and improves adsorption kinetics and catalytic performance. The sheet has great potential for application in energy, catalysis, wave absorption, and the environment.

[0007] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0008] In a first aspect, the present invention provides a method for preparing metal phthalocyanine / cobalt hydroxide knitted hexagonal micron sheets, comprising the following steps:

[0009] S1. ultrasonically dissolving a cobalt salt in deionized water to obtain a cobalt salt solution, further adding a metal phthalocyanine compound to the solution, and ultrasonically dispersing the solution to obtain a mixed solution;

[0010] S2. placing ammonium bicarbonate or ammonium carbonate at the bottom of a reaction device having a porous sieve plate, placing the mixed solution in a container and placing the container on the porous sieve plate to perform a biomimetic mineralization synthesis reaction;

[0011] S3. After the reaction is completed, the solution in the container is filtered, the filtered solid is washed by centrifugation, and the solid is dried to obtain metal phthalocyanine / cobalt hydroxide knitted hexagonal micron sheets.

[0012] Preferably, the molar ratio of the cobalt salt to the metal phthalocyanine compound is 5-20:1.

[0013] Preferably, the cobalt salt includes at least one of cobalt chloride, cobalt sulfate, cobalt nitrate and cobalt acetate.

[0014] Preferably, the metal phthalocyanine compound includes at least one of tetraaminophthalocyanine cobalt, tetraaminophthalocyanine nickel, tetraaminophthalocyanine zinc and tetraaminophthalocyanine magnesium.

[0015] Preferably, the molar ratio of ammonium bicarbonate or ammonium carbonate to cobalt salt is 1-5:1.

[0016] Preferably, in step S2, the temperature of the biomimetic mineralization synthesis reaction is 20-80° C., and the time is 12-48 hours.

[0017] In a second aspect, a metal phthalocyanine / cobalt hydroxide knitted hexagonal micron sheet is obtained by the preparation method described in the first aspect.

[0018] In a third aspect, the application of the metal phthalocyanine / cobalt hydroxide knitted hexagonal microsheets as described in the second aspect in the fields of adsorption, desalination, energy, catalysis, wave absorption or environment.

[0019] In a fourth aspect, a method for preparing a desalination electrode comprises the following steps:

[0020] The metal phthalocyanine / cobalt hydroxide knitted hexagonal microsheets as described in the first aspect are mixed evenly with conductive acetylene black and polyvinylidene fluoride in a mass ratio of 8:1:1, and further ethanol is added and ground to obtain an electrode slurry; the slurry is coated on a conductive substrate and dried to obtain a desalination electrode.

[0021] In a fifth aspect, a desalination electrode is obtained by the preparation method described in the fourth aspect.

[0022] The beneficial effects achieved by one or more technical solutions of the present invention are as follows:

[0023] The biomimetic mineralization synthesis strategy proposed in this paper separates the precipitant from the reaction solution. The precipitant slowly decomposes upon heating, generating precipitating gases that diffuse slowly into the metal salt solution, producing hydroxide ions. This induces the slow nucleation and growth of the metal ions, effectively avoiding the uncontrollable crystal nucleation and growth issues encountered during the one-pot synthesis process. This facilitates the production of hierarchical micro-nanostructures with precisely controlled morphology, size, and crystal form, offering advantages such as a simple preparation process, strong controllability, and mild conditions.

[0024] Detailed structural characterization of the metal phthalocyanine / cobalt hydroxide knitted hexagonal microsheets prepared by the present invention using multiple structural characterization methods revealed that the knitted hexagonal microsheet structure fully exposes reactive sites, shortens ion diffusion pathways, enhances the driving force for ion diffusion, and improves adsorption kinetics and catalytic performance, demonstrating promising applications in energy, catalysis, microwave absorption, and environmental fields. Furthermore, the unique two-dimensional macrocyclic conjugated structure of the metal phthalocyanine exhibits excellent optoelectronic properties, thus improving the conductivity of the cobalt hydroxide.

[0025] Metal phthalocyanine / cobalt hydroxide knitted hexagonal microsheets were prepared as desalination electrodes and various desalination performance tests such as salt adsorption capacity, cycle performance and charge efficiency were carried out. The results showed that metal phthalocyanine / cobalt hydroxide knitted hexagonal microsheets had excellent desalination performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0027] Figure 1 Schematic diagram of the reaction device;

[0028] Figure 2 This is a low-magnification scanning electron microscope photograph of the cobalt phthalocyanine / cobalt hydroxide knitted hexagonal microsheet composite material obtained in Example 1;

[0029] Figure 3 This is a high-magnification scanning electron microscope photograph of the cobalt phthalocyanine / cobalt hydroxide knitted hexagonal microsheet composite material obtained in Example 1;

[0030] Figure 4 This is the X-ray diffraction pattern of the cobalt phthalocyanine / cobalt hydroxide knitted hexagonal micron sheet composite material obtained in Example 1;

[0031] Figure 5 This is the X-ray photoelectron spectrum of the cobalt phthalocyanine / cobalt hydroxide knitted hexagonal microsheet composite material obtained in Example 1;

[0032] Figure 6 This is the nitrogen adsorption-desorption isotherm of the cobalt phthalocyanine / cobalt hydroxide knitted hexagonal microsheet composite material obtained in Example 1;

[0033] Figure 7 This is a graph showing the change in salt adsorption over time of the cobalt phthalocyanine / cobalt hydroxide knitted hexagonal microsheets obtained in Example 1 and the cobalt phthalocyanine / cobalt hydroxide composite material synthesized by the hydrothermal method in Comparative Example 1;

[0034] Figure 8 This is a graph showing the change in salt adsorption retention over time for the cobalt phthalocyanine / cobalt hydroxide knitted hexagonal micron sheets obtained in Example 1 and the cobalt phthalocyanine / cobalt hydroxide composite material synthesized by the hydrothermal method in Comparative Example 1;

[0035] Figure 9 This is a charge efficiency diagram of the cobalt phthalocyanine / cobalt hydroxide knitted hexagonal microsheets obtained in Example 1 and the cobalt phthalocyanine / cobalt hydroxide composite material synthesized by the hydrothermal method in Comparative Example 1. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments and comparative examples.

[0037] Example 1

[0038] 2.91 g of Co(NO₃)₂·6H₂O was weighed using an electronic balance and dissolved in 100 mL of deionized water. The solution was ultrasonically dispersed for 30 minutes to obtain a clear solution. 0.63 g of cobalt tetraaminophthalocyanine was weighed and ultrasonically dispersed in the metal salt solution. The resulting mixed solution was placed in a beaker and placed above the porous sieve plate in the reactor. Subsequently, 1.6 g of ammonium bicarbonate (a precipitant) was weighed using an electronic balance and placed at the bottom of the reactor. The reactor was placed in an oven and subjected to biomimetic mineralization synthesis at 30°C. After 24 hours, the beaker containing the solution was removed and the supernatant was removed by centrifugation to obtain a precipitate. The product was washed several times with deionized water and anhydrous ethanol to remove unreacted reagents, and then vacuum-dried at 60°C for 12 hours to obtain knitted hexagonal microsheets of cobalt phthalocyanine / cobalt hydroxide.

[0039] Figure 1 This is a schematic diagram of the biomimetic mineralization synthesis reaction device. Figure 2 and Figure 3 This is a scanning electron microscope image of the resulting cobalt phthalocyanine / cobalt hydroxide knitted hexagonal microsheets, clearly showing the uniform hexagonal microsheet structure. The microsheets are approximately 10 μm in size and contain numerous interlaced needle-like structures with diameters of tens of nanometers and lengths of several microns. Figure 4 Figure 3 is the XRD pattern of the obtained cobalt phthalocyanine / cobalt hydroxide knitted hexagonal microsheets, in which there are four obvious diffraction peaks at 19.5°, 32.6°, 38.3° and 51.9°, which are respectively attributed to the (001), (100), (101), (102), (110), (111), (103) and (201) crystal planes of cobalt hydroxide (JCPDS No. 30-0443). It can be inferred that the target material was successfully synthesized using the biomimetic mineralization synthesis reaction. Figure 5 This is the XPS spectrum of the obtained cobalt phthalocyanine / cobalt hydroxide knitted hexagonal microsheets. The signals of the three elements carbon, oxygen and cobalt can be clearly observed, which further confirms the successful synthesis of the target material. Figure 6 The nitrogen adsorption-desorption curve of the obtained cobalt phthalocyanine / cobalt hydroxide knitted hexagonal microsheets is shown in Figure 2. The specific surface area of ​​the prepared cobalt phthalocyanine / cobalt hydroxide knitted hexagonal microsheets is 27.8 m 2 / g.

[0040] Comparative Example 1

[0041] 2.91 g of Co(NO₃)₂·6H₂O was weighed using an electronic balance and dissolved in 100 mL of deionized water. The solution was ultrasonically dispersed for 30 minutes to obtain a clear solution. 0.63 g of cobalt tetraaminophthalocyanine was weighed and ultrasonically dispersed in the metal salt solution. The resulting mixed solution was placed in a reactor, and 1.6 g of ammonium bicarbonate, a precipitant, was weighed using an electronic balance and added to the reactor. The reactor was placed in an oven and subjected to a hydrothermal reaction at 120°C. After 12 hours, the beaker containing the solution was removed and the supernatant was removed by centrifugation to obtain a precipitate. The product was washed several times with deionized water and anhydrous ethanol to remove unreacted reagents, and then vacuum-dried at 60°C for 12 hours to obtain a cobalt phthalocyanine / cobalt hydroxide composite material.

[0042] Experimental Example 1

[0043] The cobalt phthalocyanine / cobalt hydroxide knitted hexagonal microsheets obtained in Example 1 and the cobalt phthalocyanine / cobalt hydroxide composite material synthesized by the hydrothermal method in Comparative Example 1 were mixed with conductive acetylene black and polyvinylidene fluoride at a mass ratio of 8:1:1. The mixture was then ground in a mortar with a small amount of ethanol to produce an electrode slurry. The slurry was then coated onto a 3 cm x 3 cm piece of graphite paper, transferred to a vacuum drying oven, and dried at 80°C for 24 hours to produce a desalination electrode.

[0044] The desalination electrode obtained above was assembled into a CDI module with organic glass plates (for support), copper foil (conductors), silicone gaskets (sealants), etc., and placed in a sodium chloride solution with a concentration of 300 mg / L for desalination testing. The CDI test device mainly consists of five parts: power supply, peristaltic pump, CDI module, ion conductivity meter and water reservoir. Under the action of the peristaltic pump, the sodium chloride solution enters the CDI module from the water reservoir through the catheter. A certain voltage is applied to both ends of the CDI module, an adsorption process occurs, and then flows out of the CDI module through the ion conductivity meter and finally into the water reservoir. The ion conductivity meter can monitor the conductivity changes of the brine in real time and transmit the data to a computer. According to the standard curve and the change in conductivity, the change in solution concentration can be obtained. Figure 7 The chart shows the salt adsorption trends over time for knitted hexagonal microsheets of cobalt phthalocyanine / cobalt hydroxide and a hydrothermal-synthesized cobalt phthalocyanine / cobalt hydroxide composite. The biomimetic mineralization-derived knitted hexagonal microsheets exhibited a salt adsorption capacity of 52.3 mg / g, significantly exceeding the 26.9 mg / g salt adsorption of the hydrothermal-synthesized cobalt phthalocyanine / cobalt hydroxide composite. Figure 8The following graph shows the salt adsorption retention over time for knitted hexagonal microsheets of cobalt phthalocyanine / cobalt hydroxide and a hydrothermally synthesized cobalt phthalocyanine / cobalt hydroxide composite. The knitted hexagonal microsheets of cobalt phthalocyanine / cobalt hydroxide synthesized by the biomimetic mineralization method retained 93.47% of their salt adsorption after 50 desalination cycles, while the salt adsorption of the hydrothermally synthesized cobalt phthalocyanine / cobalt hydroxide composite decreased to 67.30% after 50 cycles, significantly lower than the former. Figure 9 The charge efficiency diagram of cobalt phthalocyanine / cobalt hydroxide knitted hexagonal microsheets and cobalt phthalocyanine / cobalt hydroxide composites synthesized by the hydrothermal method. The charge efficiency of cobalt phthalocyanine / cobalt hydroxide knitted hexagonal microsheets at 0.8V is as high as 79.3%, and even when the voltage is increased to 1.0V and 1.2V, the charge efficiency can still reach 74.6% and 71.0%. The charge efficiency of cobalt phthalocyanine / cobalt hydroxide synthesized by the hydrothermal method is 65.5%, 60.0%, and 54.1% at 0.8V, 1.0V, and 1.2V, respectively. These results show that the prepared cobalt phthalocyanine / cobalt hydroxide knitted hexagonal microsheets have excellent desalination performance, thanks to the special structure constructed by the biomimetic mineralization synthesis method, confirming the great advantages of the biomimetic mineralization synthesis method.

[0045] Example 2

[0046] The difference from Example 1 is that Co(NO3)2·6H2O is replaced by 2.49 g of Co(CHCOO)·4HO.

[0047] Example 3

[0048] The difference from Example 1 is that Co(NO3)2·6H2O is replaced by 2.81 g of CoSO4·7H2O.

[0049] Example 4

[0050] The difference from Example 1 is that Co(NO3)2·6H2O is replaced by 1.48 g of CoCl2·6H2O.

[0051] Example 5

[0052] Different from Example 1, 5.82 g of Co(NO3)2·6H2O was weighed.

[0053] Example 6

[0054] The difference from Example 1 is that 0.63 g of nickel tetraaminophthalocyanine is used as the metal phthalocyanine.

[0055] Example 7

[0056] The difference from Example 1 is that 0.64 g of zinc tetraaminophthalocyanine is used as the metal phthalocyanine.

[0057] Example 8

[0058] The difference from Example 1 is that 0.59 g of magnesium tetraaminophthalocyanine is used as the metal phthalocyanine.

[0059] Example 9

[0060] The difference from Example 1 is that the reaction temperature is 40°C.

[0061] Example 10

[0062] The difference from Example 1 is that the reaction temperature is 50°C.

[0063] Example 11

[0064] The difference from Example 1 is that the reaction temperature is 60°C.

[0065] Example 12

[0066] The difference from Example 1 is that the reaction time is 12 hours.

[0067] Example 13

[0068] The difference from Example 1 is that the reaction time is 36 hours.

[0069] Example 14

[0070] The difference from Example 1 is that the reaction time is 48 hours.

[0071] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for preparing metal phthalocyanine / cobalt hydroxide knitted hexagonal micron sheets for desalination, characterized in that: The following steps are involved: S1. ultrasonically dissolving a cobalt salt in deionized water to obtain a cobalt salt solution, further adding a metal phthalocyanine compound to the solution, and ultrasonically dispersing the solution to obtain a mixed solution; S2. placing ammonium bicarbonate or ammonium carbonate at the bottom of a reaction device having a porous sieve plate, placing the mixed solution in a container and placing it on the porous sieve plate to perform a biomimetic mineralization synthesis reaction; the molar ratio of ammonium bicarbonate or ammonium carbonate to cobalt salt is 1-5:1; the biomimetic mineralization synthesis reaction is performed at a temperature of 20-80° C. and for a time of 12-48 hours; S3. After the reaction is completed, the solution in the container is filtered, the filtered solid is washed by centrifugation, and the solid is dried to obtain metal phthalocyanine / cobalt hydroxide knitted hexagonal micron sheets.

2. The preparation method according to claim 1, wherein The molar ratio of the cobalt salt to the metal phthalocyanine compound is 5-20:

1.

3. The preparation method according to claim 1, wherein The cobalt salt includes at least one of cobalt chloride, cobalt sulfate, cobalt nitrate and cobalt acetate.

4. The preparation method according to claim 1, wherein The metal phthalocyanine compound includes at least one of tetraaminophthalocyanine cobalt, tetraaminophthalocyanine nickel, tetraaminophthalocyanine zinc and tetraaminophthalocyanine magnesium.

5. A metal phthalocyanine / cobalt hydroxide knitted hexagonal micron sheet, characterized in that: The method is obtained by the preparation method according to any one of claims 1 to 4.

6. Use of the metal phthalocyanine / cobalt hydroxide knitted hexagonal microsheets as claimed in claim 5 in desalination.

7. A method for preparing a desalination electrode, characterized in that: The following steps are involved: The metal phthalocyanine / cobalt hydroxide knitted hexagonal microsheets as claimed in claim 5 are uniformly mixed with conductive acetylene black and polyvinylidene fluoride in a mass ratio of 8:1:1, and further ethanol is added and ground to obtain an electrode slurry; the slurry is coated on a conductive substrate and dried to obtain a desalination electrode.

8. A desalination electrode, characterized in that: Obtained by the preparation method according to claim 7.

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