Adsorption and conductive integrated electrode material and preparation method thereof

Abstract

The application provides an adsorption and conductive integrated electrode material and a preparation method thereof, relates to the technical field of chemical adsorbents, and aims to solve the problem that there is no effective method for adsorbing and catalytically reducing carbon dioxide in water environment in the prior art. The method comprises the following steps: firstly, dissolving an inorganic copper source in deionized water, then adding alkali metal hydroxide and H2N-CN to perform a polymerization reaction, filtering and vacuum freeze-drying to obtain a catalyst; secondly, dissolving chitosan in an acetic acid solution under heating, then adding citric acid, stirring and then standing until no air bubbles are generated to obtain a carrier material; thirdly, dropping the carrier material on the surface of a hydrophobic film, covering the hydrophobic film with another hydrophobic film, gently pressing, and repeatedly performing freeze-thaw operations until a cross-linked sheet is formed, uniformly coating the catalyst on the surface of the sheet, and freeze-drying to obtain the adsorption and conductive integrated electrode material, which is used for treating carbon dioxide in water through adsorption and catalytic reduction.

Description

Technical Field

[0001] This invention relates to the field of chemical adsorbent technology, and more specifically, to an integrated adsorption and conductivity electrode material and its preparation method. Background Technology

[0002] Global warming is becoming a major challenge facing the world today. Increased atmospheric CO2 concentration leads to increased CO2 dissolution in seawater, and decreased pH causes ocean acidification, further exacerbating marine pollution and ecosystem damage. In addition to reducing carbon emissions, addressing already emitted CO2 is crucial to solving these problems. The concentration of carbon dioxide in the ocean is more than 100 times higher than in the air, accounting for 93% of the natural carbon sink, and the cost of liquid-phase enrichment and desorption is far lower than that of gas-phase enrichment, with a difference of up to an order of magnitude. Meanwhile, methanol, as one of the five major commercial chemicals, is the most economically valuable C1 chemical derived from carbon dioxide. Therefore, offshore methanol conversion systems have significant advantages in both economics and efficiency.

[0003] Biomass chitosan, the only naturally occurring alkaline cationic polysaccharide in nature, can be obtained from the cell walls of shrimp, crabs, crustaceans, and plants through deacetylation reactions. It boasts advantages such as abundant reserves, biodegradability, and non-toxicity. The C2-NH2 phase in the chitosan molecular chain can serve as a CO2 recognition site, and its excellent biocompatibility allows it to be modified through physical and chemical methods into various forms of materials, including membranes, activated carbon, and catalysts, facilitating its application in various fields such as CO2 separation, capture, and resource utilization. It is non-toxic, pollution-free, and easily degradable, and can remain functional in water for extended periods.

[0004] Jilin University's CN117430130A discloses a modified SAPO-56 zeolite molecular sieve, its preparation method, and its applications. They mixed a silicon source, an aluminum source, phosphoric acid, a template agent, and water to obtain an initial reaction gel; crystallized the initial reaction gel to obtain a SAPO-56 zeolite molecular sieve; then, they mixed the SAPO-56 zeolite molecular sieve with a cation solution for ion exchange; finally, they calcined the resulting ion exchange product to obtain the modified SAPO-56 zeolite molecular sieve. The prepared modified SAPO-56 zeolite molecular sieve exhibits high crystallinity and significantly improved carbon dioxide adsorption performance compared to raw SAPO-56 molecular sieve powder. However, the cations in the cation solution include alkali metal ions or lanthanide rare earth metal ions, posing issues related to cost and rare earth resources.

[0005] The Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, has invented an amine-based columnar aromatic hydrocarbon selective adsorbent for carbon dioxide (CO2) using patent CN117339563A. This adsorbent is applied to the selective adsorption and separation of CO2 from methane and nitrogen. Experiments have demonstrated that this adsorbent has good separation potential for CO2 and nitrogen, as well as CO2 and methane, and exhibits good reusability. It can be used for the efficient capture and storage of CO2 in industrial flue gas or mixed gases. However, the materials used in its production contain substances such as paraformaldehyde that pollute water bodies, posing an environmental risk.

[0006] Shanghai Yike Polymer Technology Co., Ltd.'s CN117919968A is a carbon dioxide composite separation membrane used in flue gas treatment. Carbon dioxide can reversibly react with amine compounds in the hydrogel matrix layer of the composite separation membrane to form an intermediate, which can rapidly diffuse within the hydrogel matrix layer. Non-reactive gases, such as nitrogen, are blocked by the hydrogel matrix layer and cannot pass through. Although this patent uses chitosan as a substrate, solving problems such as decreased adsorption efficiency due to environmental pollution and humid air, it lacks subsequent carbon dioxide treatment, remaining only at the adsorption and separation level. Summary of the Invention

[0007] The technical problem to be solved by this invention is:

[0008] Existing technologies lack effective methods for integrated adsorption and catalytic treatment of carbon dioxide in aquatic environments, and often fail to address the issues of secondary pollution and high cost of treatment materials.

[0009] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0010] This invention provides a method for preparing an integrated adsorption and conductivity electrode material, comprising the following steps:

[0011] I. Catalyst preparation: First, the inorganic copper source is dissolved in deionized water, then alkali metal hydroxide and H2N-CN are added to carry out a polymerization reaction, filtered, and freeze-dried under vacuum to obtain the catalyst;

[0012] 2. Cross-linking and mounting: Chitosan is dissolved in acetic acid solution under heating conditions, and then citric acid is added under heating conditions. After stirring, the mixture is allowed to stand until no bubbles are present to obtain the carrier material.

[0013] 3. Shaping: The carrier material is dropped onto the surface of a hydrophobic membrane, then covered with another hydrophobic membrane, and gently pressed. The freeze-thaw operation is repeated until a cross-linked sheet is formed. The catalyst obtained in step 1 is evenly coated on the surface of the sheet and freeze-dried to obtain the integrated adsorption and conductivity electrode material.

[0014] Furthermore, in step one, the molar ratio of the inorganic copper source, alkali metal hydroxide, and H2N-CN is 0.44-0.6:1.5-2.5:1.

[0015] Furthermore, the inorganic copper source mentioned in step one is one or more of copper chloride, copper nitrate, or copper sulfate.

[0016] Furthermore, the alkali metal hydroxide mentioned in step one is one or more of sodium hydroxide or potassium hydroxide.

[0017] Furthermore, the vacuum freeze-drying time in step one is 36-38 hours.

[0018] Further, step two specifically involves: dissolving 3-4 parts by mass of chitosan in 100 parts by mass of 3-4 wt% acetic acid solution under heating conditions, then adding 0.5-1 parts by mass of citric acid under heating conditions, stirring, and allowing it to stand until no bubbles are present to obtain the carrier material;

[0019] Furthermore, in step three, the freezing temperature for the freezing and thawing operation is -18 to -20°C, and the freezing time is 24-26 hours.

[0020] Furthermore, in step three, the mass ratio of the support material to the catalyst is 1:0.025-0.03.

[0021] An adsorption and conductivity integrated electrode material prepared by any of the above technical solutions.

[0022] The application of the integrated adsorption and conductivity electrode material described in the above technical solution in water treatment by adsorbing and catalytically reducing carbon dioxide in water.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] This invention proposes an integrated structure combining a copper atom catalyst with a chitosan adsorption membrane. The chitosan cross-linked membrane acts as both an adsorption and electrode material, enriching carbon dioxide in seawater. The amine and hydrophilic groups in chitosan can interact with carbon dioxide molecules, and the porous structure of the membrane facilitates the adsorption and storage of carbon dioxide, achieving a superior adsorption effect. The catalyst supported on the chitosan cross-linked membrane forms a catalytic electrode with the chitosan, integrating adsorption and electrode materials. This results in more efficient processing, simpler operation, and lower costs. Furthermore, the raw materials used in this invention are easily degradable, environmentally friendly, and suitable for large-scale production and use. Attached Figure Description

[0025] Figure 1 Images of the integrated adsorption and conductivity electrode material in the embodiments of the present invention;

[0026] Figure 2This is a graph showing the XPS detection results of the catalyst in an embodiment of the present invention;

[0027] Figure 3 The above is the NMR spectrum of the electrolyte in the embodiments of the present invention;

[0028] Figure 4 Figure 1 shows the Raman spectra of the electrode materials in the embodiments of the present invention. Figure 2 shows the Raman spectrum of the electrode material without catalyst coating, and Figure 3 shows the Raman spectrum of the adsorption and conduction integrated electrode material of the present invention.

[0029] Figure 5 This is the voltage relaxation time distribution of 1.2V, 1.5V, and 1.8V in the embodiments of the present invention;

[0030] Figure 6 Figure (a) shows the Nyquist curves under different voltage conditions in the embodiments of the present invention; Figure (b) shows the voltage and relaxation time distribution.

[0031] Figure 7 This is a simulated structural diagram of the catalyst in the embodiments of the present invention. Detailed Implementation

[0032] To enable those skilled in the art to better understand the present invention, exemplary embodiments or examples of the present invention will be described below in conjunction with the accompanying drawings. Obviously, the described embodiments or examples are merely some, not all, of the embodiments or examples of the present invention. All other embodiments or examples obtained by those skilled in the art based on the embodiments or examples of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0033] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0034] This invention provides a method for preparing an integrated adsorption and conductivity electrode material, comprising the following steps:

[0035] I. Catalyst preparation: First, the inorganic copper source is dissolved in deionized water, then alkali metal hydroxide and H2N-CN are added to carry out a polymerization reaction, filtered, and freeze-dried under vacuum to obtain the catalyst;

[0036] 2. Cross-linking and mounting: Chitosan is dissolved in acetic acid solution under heating conditions, and then citric acid is added under heating conditions. After stirring, the mixture is allowed to stand until no bubbles are present to obtain the carrier material.

[0037] 3. Shaping: The carrier material is dropped onto the surface of a hydrophobic membrane, then covered with another hydrophobic membrane, and gently pressed. The freeze-thaw operation is repeated until a cross-linked sheet is formed. The catalyst obtained in step 1 is evenly coated on the surface of the sheet and freeze-dried to obtain the integrated adsorption and conductivity electrode material.

[0038] In this invention, the molar ratio of inorganic copper source, alkali metal hydroxide and H2N-CN can be selected within a wide range. In order to further improve the adsorption and catalytic performance of the integrated adsorption and conductivity electrode material, preferably, the molar ratio of inorganic copper source, alkali metal hydroxide and H2N-CN in step one is 0.44-0.6:1.5-2.5:1.

[0039] In this invention, there are no particular restrictions on the type of inorganic copper source in step one. Preferably, the inorganic copper source is one or more of copper chloride, copper nitrate, or copper sulfate.

[0040] In this invention, there are no particular restrictions on the type of alkali metal in step one. Preferably, the alkali metal hydroxide is one or more of sodium hydroxide or potassium hydroxide.

[0041] In this invention, the vacuum freeze-drying time in step one can be selected within a wide range. Preferably, the vacuum freeze-drying time is 36-38 hours.

[0042] In this invention, preferably, step two specifically involves: dissolving 3-4 parts by mass of chitosan in 100 parts by mass of 3-4 wt% acetic acid solution at 50-60°C, then adding 0.5-1 parts by mass of citric acid at 50-60°C, stirring, and allowing to stand until no bubbles are present to obtain the carrier material;

[0043] In this invention, the freezing temperature and time of the freezing and thawing operation in step three can be selected within a wide range. Preferably, the freezing temperature of the freezing and thawing operation in step three is -18 to -20°C, and the freezing time is 24-26 hours.

[0044] In this invention, there are no particular restrictions on the mass (or thickness) of the catalyst coated on the surface of the sheet in step three. Preferably, the mass ratio of the support material to the catalyst is 1:0.025-0.03.

[0045] The present invention also provides an integrated adsorption and conductivity electrode material prepared by the above preparation method; and the application of the integrated adsorption and conductivity electrode material in liquid-phase adsorption catalytic reduction of carbon dioxide.

[0046] Example 1

[0047] I. Catalyst preparation: First, 2.2 mmol of copper chloride was dissolved in 50 ml of deionized water at room temperature. Then, 7.5 mmol of sodium hydroxide and 5 mmol of H2N-CN were added to carry out the polymerization reaction. The mixture was filtered, freeze-dried under vacuum, and washed with deionized water to obtain the catalyst.

[0048] 2. Cross-linking and mounting: Dissolve 4g of chitosan in 100ml of 3wt% acetic acid solution at 60℃, then add 0.5g of citric acid at 60℃, stir for 30min, and let stand until no bubbles are present to obtain the carrier material.

[0049] III. Shaping: 2g of the carrier material is dropped onto the surface of a polytetrafluoroethylene (PTFE) membrane, then covered with another PTFE membrane and gently pressed. The membrane is then frozen at -20°C for 24 hours, removed, and thawed for 4 hours. This freezing and thawing process is repeated twice until a cross-linked sheet is formed. The 0.05g catalyst obtained in step one is then evenly coated onto the surface of the sheet, and the sheet is freeze-dried for 36 hours to obtain the desired product. Figure 1 The electrode material shown is an integrated adsorption and conductivity electrode.

[0050] Example 2

[0051] I. Catalyst preparation: First, 3 mmol of copper chloride was dissolved in 50 ml of deionized water at room temperature. Then, 12.5 mmol of sodium hydroxide and 5 mmol of H2N-CN were added to carry out the polymerization reaction. The mixture was filtered, freeze-dried under vacuum, and washed with deionized water to obtain the catalyst.

[0052] 2. Cross-linking and mounting: Dissolve 3g of chitosan in 100ml of 4wt% acetic acid solution at 60℃, then add 1g of citric acid at 60℃, stir for 30min, and let stand until no bubbles are present to obtain the carrier material.

[0053] III. Shaping: 2g of the carrier material is dropped onto the surface of a polytetrafluoroethylene (PTFE) membrane, then covered with another PTFE membrane, gently pressed, and frozen at -20°C for 24 hours. It is then removed and thawed for 4 hours. This freezing and thawing process is repeated twice until a cross-linked sheet is formed. The 0.06g catalyst obtained in step one is then evenly coated onto the surface of the sheet, and freeze-dried for 36 hours to obtain the desired product. Figure 1 The electrode material shown is an integrated adsorption and conductivity electrode.

[0054] The catalyst obtained in Example 1 was subjected to XPS analysis, and the results are as follows: Figure 2 As shown, the results of crosslinking of copper, carbon, and nitrogen in the catalyst can be seen, and the crosslinking did not change or affect the catalyst structure.

[0055] Raman spectroscopy was performed on the integrated adsorption and conductivity electrode material of Example 1 and the electrode material without catalyst coating. The results are as follows: Figure 4 As shown, it can be seen that both materials have electrical conductivity. The addition of a catalyst enhances the conductivity of the materials, making them suitable for preparing conductive electrodes.

[0056] The catalyst obtained in Example 1 (particle size 5 nm) and an existing catalyst with a particle size of 10 nm were dissolved in ethanol to obtain a solution. The solution was mounted on carbon cloth, dried, and used as the cathode and a platinum anode. Sodium bicarbonate was electrolyzed, and the voltage was varied. The mass transfer and reaction coupling characteristics of the electrodes were tested using EIS (electrochemical impedance spectroscopy), and the relaxation time distribution of the response was calculated. The results are as follows: Figure 5 and Figure 6 As shown, the results indicate that the porous structure design optimizes the matching of mass transfer and reaction rate during the reaction process, significantly improving the catalytic CO2 reaction rate. This demonstrates that the porous design of this invention optimizes the catalyst properties from a topological perspective, avoids the difficulties of synthesizing materials at extremely small scales, greatly reduces production costs, and enhances material competitiveness.

[0057] Application Example 1

[0058] The adsorption and conductivity integrated electrode material obtained in Example 1 was used as the working electrode to treat carbon dioxide in the electrolyte. The specific operation is as follows:

[0059] Using the integrated adsorption and conductivity electrode material obtained in Example 1 as the cathode, a platinum sheet as the anode, and 0.5 mol / L potassium bicarbonate as the electrolyte, carbon dioxide was introduced into the electrolyte before electrolysis. Electrolysis was performed at 3V for 0.5 h. The electrolyte was then subjected to NMR spectroscopy, and the results are as follows: Figure 3 As shown. From Figure 3 As can be seen, methanol is generated in the electrolyte after electrolysis, indicating that the electrode material of the present invention can achieve efficient reduction of liquid carbon dioxide.

[0060] like Figure 7 As shown, the copper-oxygen bond in the catalyst of this invention is easier to break than the carbon-oxygen bond, and it is easier to form a methyl oxygen free radical, which can be used as a methanol precursor. It is also easier to reduce carbon dioxide in the liquid phase to methanol, and finally realize the treatment of carbon dioxide in the liquid phase and the regeneration and utilization of methanol energy.

[0061] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A method for preparing an integrated adsorption and conductivity electrode material, characterized in that, Includes the following steps: I. Catalyst preparation: First, the inorganic copper source is dissolved in deionized water, then alkali metal hydroxide and H2N-CN are added to carry out a polymerization reaction, filtered, and freeze-dried under vacuum to obtain the catalyst; 2. Cross-linking and mounting: Chitosan is dissolved in acetic acid solution under heating conditions, and then citric acid is added under heating conditions. After stirring, the mixture is allowed to stand until no bubbles are present to obtain the carrier material.

3. Shaping: The carrier material is dropped onto the surface of a hydrophobic membrane, then covered with another hydrophobic membrane, and gently pressed. The freeze-thaw operation is repeated until a cross-linked sheet is formed. The catalyst obtained in step 1 is evenly coated on the surface of the sheet and freeze-dried to obtain the integrated adsorption and conductivity electrode material.

2. The method for preparing the integrated adsorption and conductivity electrode material according to claim 1, characterized in that, In step one, the molar ratio of inorganic copper source, alkali metal hydroxide and H2N-CN is 0.44-0.6:1.5-2.5:

1.

3. The method for preparing the integrated adsorption and conductivity electrode material according to claim 1, characterized in that, The inorganic copper source mentioned in step one is one or more of copper chloride, copper nitrate, or copper sulfate.

4. The method for preparing the integrated adsorption and conductivity electrode material according to claim 1, characterized in that, The alkali metal hydroxide mentioned in step one is one or more of sodium hydroxide or potassium hydroxide.

5. The method for preparing the integrated adsorption and conductivity electrode material according to claim 1, characterized in that, The vacuum freeze-drying time in step one is 36-38 hours.

6. The method for preparing the integrated adsorption and conductivity electrode material according to claim 1, characterized in that, Step two specifically involves dissolving 3-4 parts by mass of chitosan in 100 parts by mass of 3-4 wt% acetic acid solution under heating conditions, then adding 0.5-1 parts by mass of citric acid under heating conditions, stirring, and allowing it to stand until no bubbles are present to obtain the carrier material.

7. The method for preparing the integrated adsorption and conductivity electrode material according to claim 1, characterized in that, In step three, the freezing temperature for the freezing and thawing process is -18 to -20°C, and the freezing time is 24 to 26 hours.

8. The method for preparing the integrated adsorption and conductivity electrode material according to claim 1, characterized in that, In step three, the mass ratio of the support material to the catalyst is 1:0.025-0.

03.

9. An adsorption and conductivity integrated electrode material prepared by the preparation method according to any one of claims 1-8.

10. The application of the integrated adsorption and conductivity electrode material of claim 9 in water treatment by adsorbing and catalytically reducing carbon dioxide in water.

Images