Supported annular hydroxyl cobalt oxide carbon dioxide adsorption material as well as preparation method and application thereof
Cyclic cobalt hydroxyl oxide (CoOOH) materials were prepared by electrochemical deposition and alkaline treatment, which solved the morphology and stability problems of CoOOH in CO2 adsorption and achieved efficient and stable CO2 capture, suitable for industrial flue gas treatment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-18
- Publication Date
- 2026-03-10
AI Technical Summary
Existing carbon capture materials such as CoOOH suffer from problems such as monotonous morphology, limited specific surface area, unstable structure, and easy agglomeration in the field of CO2 adsorption, making it difficult to meet the stability and economic requirements of industrial applications.
A cyclic cobalt hydroxyl oxide precursor was generated on the surface of carbon cloth by electrochemical deposition. Combined with alkaline solution treatment, a cyclic cobalt hydroxyl oxide material with high specific surface area was formed. Through the synergistic mechanism of electrodeposition-alkaline post-treatment, the cyclic structure design and precise construction of highly active sites of the material were realized.
The prepared cyclic cobalt hydroxyl oxide material has a high specific surface area and excellent cycling stability, making it suitable for efficient capture of low-concentration CO2. It improves CO2 adsorption capacity and adsorption kinetics performance, and is applicable to flue gas carbon capture in the power and chemical industries.
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Figure CN121623744A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of gas adsorption technology, in particular to a carbon dioxide gas adsorption material, and specifically to a supported cobalt hydroxyl oxide ring carbon dioxide adsorption material, a preparation method and application thereof. BACKGROUND
[0002] In the face of the urgent demand for global carbon neutrality, carbon capture, utilization and storage (CCUS) technology has become an irreplaceable key path for industrial deep decarbonization. With the continuous strengthening of emission reduction policies in various countries, CCUS technology is accelerating from the demonstration stage to large-scale commercial application. However, the current carbon capture technology system still has significant bottlenecks: although the mainstream amine liquid absorption method is relatively mature, its high regeneration energy consumption and serious equipment corrosion problems lead to high operating costs; emerging solid adsorption materials such as metal organic frameworks (MOFs) or functionalized molecular sieves, although they exhibit certain adsorption selectivity, their complex synthesis process, high raw material cost and structural instability in a hydrothermal environment seriously restrict their widespread application in large industrial scenarios.
[0003] Cobalt hydroxyl oxide (CoOOH) is a transition metal hydroxyl oxide rich in hydroxyl groups and metal active sites. Due to its unique electronic structure and surface chemical properties, it has been widely studied and applied in battery electrode materials, supercapacitors, and electrocatalysis for a long time. It is a multifunctional inorganic material with great development potential. However, in the field of CO2 adsorption, CoOOH has not been substantially developed and applied, and a mature preparation process and application system have not been formed.
[0004] Currently, it has been found in practice that if CoOOH is attempted to be expanded to the CO2 adsorption field, it will face many obstacles caused by intrinsic defects: first, the CoOOH prepared by traditional methods has a single morphology, mostly conventional structures such as nanosheets and particles, with limited specific surface area, making it difficult to provide sufficient adsorption sites; second, CoOOH that has not been specially structurally regulated is prone to problems such as loss of active sites and structural collapse during the adsorption-desorption cycle, which cannot meet the long-term requirements of industrial carbon capture for material stability; third, traditional preparation techniques (such as hydrothermal method) are difficult to precisely control the micro-morphology and interface bonding state, and if directly loaded on a carrier, it is also prone to problems such as agglomeration and weak bonding, further limiting its application possibilities in the field of CO2 adsorption.
[0005] Therefore, developing a new type of CoOOH with structural stability and high specific surface area, and an innovative preparation process capable of realizing precise construction of CoOOH morphology and guaranteeing its structural stability and high specific surface area, while expanding its application in the field of CO2 adsorption, is the core of breaking through the performance bottleneck of current carbon capture materials and expanding the application boundary of CoOOH. The ideal solution needs to balance material performance and industrial economy, that is, to significantly improve the adsorption capacity and cycle stability while ensuring low cost and ease of operation in the preparation process, to meet the economic and practicality requirements of large-scale carbon capture in high-emission industries such as power and chemical industry. SUMMARY
[0006] The purpose of the present application is to overcome one or more deficiencies in the prior art and provide a new type of supported cobalt hydroxyl oxide carbon dioxide adsorption material.
[0007] The present application also provides an application of the above-mentioned carbon dioxide adsorption material in a carbon dioxide adsorption equipment.
[0008] To achieve the above-mentioned purpose, one technical solution adopted by the present application is: A preparation method of a carbon dioxide adsorption material, characterized in that the preparation method comprises: In the presence of a reference electrode and an electrolyte, an electrochemical deposition occurs with carbon cloth as a working electrode and a carbon rod as a counter electrode, generating a cobalt hydroxyl oxide precursor on the carbon cloth to obtain an intermediate combined with the carbon cloth and the cobalt hydroxyl oxide precursor; and the intermediate is immersed in an alkali solution to generate a carbon dioxide adsorption material. The electrolyte comprises a cobalt salt, boric acid and water. The carbon dioxide adsorption material comprises carbon cloth and cobalt hydroxyl oxide combined with the carbon cloth.
[0009] In some embodiments of the present application, the concentration of the cobalt salt in the electrolyte is 0.01-0.1 mol / L, for example, it can be 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L, 0.1 mol / L, etc.
[0010] In some embodiments of the present application, the concentration of the boric acid is 0.1-0.5 mol / L, for example, it can be 0.1 mol / L, 0.15 mol / L, 0.20 mol / L, 0.25 mol / L, 0.30 mol / L, 0.35 mol / L, 0.40 mol / L, 0.45 mol / L, 0.5 mol / L, etc.
[0011] In some embodiments of the present invention, the cobalt salt includes one or more combinations of divalent cobalt ion nitrates, sulfates and halides, and further, the cobalt salt includes one or more combinations of cobalt nitrate, cobalt sulfate and cobalt chloride.
[0012] According to the present invention, the cobalt salt can be a pure salt without crystallization or a hydrate containing crystallization. For example, when cobalt nitrate is selected as the cobalt salt, cobalt nitrate hexahydrate can be used.
[0013] In some embodiments of the present invention, the reference electrode is a saturated calomel electrode.
[0014] In some embodiments of the present invention, the counter electrode is a graphite rod.
[0015] In some embodiments of the present invention, the carbon cloth is a hydrophilic carbon cloth.
[0016] In some embodiments of the present invention, the operating voltage of the electrochemical deposition is controlled to be -1.1 to -1.4V vs. SCE.
[0017] In some embodiments of the present invention, the electrochemical deposition time is controlled to be 400-800 seconds.
[0018] In some embodiments of the present invention, the concentration of the alkaline solution is 0.5-1 mol / L, for example, it can be 0.5 mol / L, 0.55 mol / L, 0.60 mol / L, 0.65 mol / L, 0.70 mol / L, 0.75 mol / L, 0.80 mol / L, 0.85 mol / L, 0.90 mol / L, 0.95 mol / L, 1.0 mol / L, etc.
[0019] In some embodiments of the present invention, the process of immersing the intermediate in the alkaline solution is carried out at 20-30°C.
[0020] In some embodiments of the present invention, the alkaline solution is an aqueous solution of sodium hydroxide and / or an aqueous solution of potassium hydroxide.
[0021] In some embodiments of the present invention, the intermediate is immersed in the alkaline solution for 8-24 hours, more specifically 12-16 hours.
[0022] Another technical solution provided by the present invention: a carbon dioxide adsorption material prepared by the preparation method of the carbon dioxide adsorption material described above.
[0023] In some embodiments of the present invention, the specific surface area of the carbon dioxide adsorbent material is greater than or equal to 90 m².2 / g, further to 90-120m 2 / g, and further to 90-105m 2 / g.
[0024] In some embodiments of the present invention, the size of the cyclic cobalt hydroxyoxide in the carbon dioxide adsorption material is less than or equal to 800 nm, and further less than or equal to 600 nm.
[0025] In some embodiments of the present invention, the method for preparing the carbon dioxide adsorbent material includes: Cobalt nitrate hexahydrate and boric acid were dissolved in deionized water and stirred until completely dissolved to prepare an electrolyte. Carbon cloth was cut as the working electrode, a saturated calomel electrode as the reference electrode, and a graphite rod as the counter electrode. Electrodeposition was performed by applying a working voltage for a certain period of time. After the reaction was completed, the carbon cloth was washed with deionized water until the pH of the carbon cloth was 7, and then washed several times with anhydrous ethanol and dried to obtain a carbon cloth-supported cyclic cobalt hydroxyl oxide precursor. Prepare an alkaline solution of a certain concentration, immerse the carbon cloth-supported cyclic cobalt hydroxyl oxide precursor obtained above in the alkaline solution, and stir the reaction at room temperature; after the reaction is completed, wash it several times with deionized water and anhydrous ethanol, and dry it to obtain the carbon cloth-supported cyclic cobalt hydroxyl oxide material, which is the carbon dioxide adsorption material.
[0026] Another technical solution provided by the present invention: a supported cyclic cobalt hydroxyoxide carbon dioxide adsorbent material, wherein the carbon dioxide adsorbent material comprises carbon cloth and cyclic cobalt hydroxyoxide bonded to the carbon cloth, the cyclic cobalt hydroxyoxide being formed sequentially by electrodeposition and alkaline etching, wherein the electrodeposition is performed in the presence of divalent cobalt salt, boric acid and a reference electrode.
[0027] According to the present invention, the crystal form of the cyclic cobalt hydroxyoxide is consistent with the crystal form of the standard card PDF07-1069 for cobalt hydroxyoxide.
[0028] Another technical solution provided by the present invention is: the application of the carbon dioxide adsorption material described above, or the supported cyclic cobalt hydroxyl oxide carbon dioxide adsorption material described above, in carbon dioxide adsorption.
[0029] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: In the preparation process of the carbon dioxide adsorption material of this invention, cobalt salt and boric acid are first dissolved in water to form a homogeneous electrolyte. Then, an innovative three-electrode electrodeposition system is adopted, with carbon cloth as the working electrode and carbon rod as the counter electrode. In the presence of a reference electrode, by applying a working voltage and controlling the deposition time, a cyclic cobalt hydroxyl oxide precursor is grown in situ on the surface of the carbon cloth by electrochemical reaction. Subsequently, the precursor is immersed in an alkaline solution to react, thereby optimizing the crystal form and stabilizing the structure of the cyclic cobalt hydroxyl oxide.
[0030] Furthermore, boric acid in the electrolyte has a dual function of pH buffering and morphology regulation. On the one hand, it can maintain the pH stability of the electrolyte system and avoid the morphology disorder of the precursor caused by sudden local pH changes during electrodeposition. On the other hand, it can regulate the nucleation rate and crystal growth direction of cobalt hydroxyoxide, laying the foundation for the formation of subsequent ring structures. This process overcomes the limitations of traditional cobalt hydroxyl oxide, which suffers from a single morphology and limited specific surface area. Through a synergistic mechanism of "electrodeposition ring formation - post-alkali treatment," it achieves the precise design of the ring structure and the construction of highly active sites, enabling the ring structure to bond tightly with the carbon cloth substrate. The surface hydroxyl groups and Co... 3+ The active sites are highly exposed. The resulting material possesses both a high specific surface area ring morphology and multi-level mass transfer channels. The electrodeposited nanorings have a hollow thin-walled structure with a specific surface area of 90–98 m². 2 ·g -1 It not only provides abundant physical adsorption sites, but its open hollow channels can also accelerate the mass transfer and diffusion of CO2 molecules, improving adsorption kinetics; it exhibits excellent CO2 adsorption capacity at room temperature (initial adsorption capacity 3.0~3.1 mmol·g). -1 Furthermore, due to the mechanical and chemical stability of its ring structure, the material retains over 90% of its capacity after 10 adsorption-desorption cycles. This technology is applicable to flue gas carbon capture scenarios in industries such as power and chemicals, providing a highly stable and high-adsorption-capacity material solution for the efficient capture of low-concentration CO2, and powerfully promoting industrial carbon emission reduction and green low-carbon transformation. Attached Figure Description
[0031] Figure 1 The images are scanning electron microscope (SEM) images of the carbon dioxide adsorbent material prepared in Example 1 of this invention at different magnifications. Figure 2 The image shows the powder X-ray diffraction (XRD) pattern of the carbon dioxide adsorbent material prepared in Example 1 of this invention. Detailed Implementation
[0032] This invention provides a method for preparing carbon cloth-supported cyclic cobalt hydroxyoxide carbon dioxide adsorbent material by electrodeposition, achieved through the following innovative process: First, cobalt salt and boric acid are dissolved in water and stirred to prepare an electrolyte. Boric acid serves a dual function of pH buffering and morphology regulation. On the one hand, it maintains the pH stability of the electrolyte system, avoiding precursor morphology disruption caused by sudden local pH changes during electrodeposition. On the other hand, it regulates the nucleation rate and crystal growth direction of cobalt hydroxyoxide, laying the foundation for the subsequent formation of the cyclic structure. Second, using carbon cloth as the working electrode and a carbon rod as the counter electrode, electrodeposition is performed in the presence of a reference electrode such as a saturated calomel electrode, growing a cyclic cobalt hydroxyoxide precursor on the carbon cloth surface through an electrochemical reaction. Subsequently, the precursor is immersed in an alkaline solution for reaction, achieving structural regulation and crystal form optimization of the cyclic cobalt hydroxyoxide. This process, through a synergistic mechanism of "electrodeposition ring formation - alkaline post-treatment," overcomes the limitations of the traditional single morphology of cobalt hydroxyoxide, achieving precise design of the cyclic structure and construction of highly active sites.
[0033] The resulting adsorbent material has the following core advantages: High specific surface area ring morphology: The electrodeposited nanorings have a hollow thin-walled structure with a specific surface area of 90-98 m². 2 ·g -1 It not only provides abundant physical adsorption sites, but its open hollow channels can also accelerate the mass transfer and diffusion of CO2 molecules, thereby improving adsorption kinetics performance. Synergistic effect of multiple adsorption sites: The surface of cyclic cobalt hydroxyl oxide contains hydroxyl (-OH) and Co 3+ Two types of active sites enable efficient chemisorption and selective capture of CO2. The hydroxyl group (-OH) acts as a basic site, reacting with acidic CO2 to bind CO2 molecules via protonation and further converting them into carbonates or bicarbonates. Co 3+ As Lewis acid sites, they can form coordinate bonds with oxygen atoms of CO2 molecules (Lewis bases), enabling the directional capture and fixation of CO2. At the same time, the physical adsorption sites provided by the ring structure can help enrich CO2 molecules. The three types of adsorption synergistically enhance the adsorption capacity and selectivity of the material for CO2. Excellent cycling stability: The electrodeposition loading method achieves strong interfacial bonding between cobalt hydroxyl oxide and carbon cloth substrate. Subsequent alkali treatment further optimizes the material crystal form and improves the structural compactness, avoiding the shedding and aggregation of the active phase during cycling. After 10 adsorption-desorption cycles, the adsorption retention rate of the material exceeds 90%, which is far superior to traditional supported materials.
[0034] In summary, the adsorbent material obtained by this invention possesses high specific surface area, synergistic effects of multiple adsorption sites, and excellent cycling stability. It exhibits high CO2 adsorption capacity and outstanding cycle retention rate in a normal temperature environment, making it suitable for the efficient capture of low-concentration CO2 in flue gas from high-emission industries such as power and chemical industries. This provides a new material pathway for the industrialization of low-cost, high-stability carbon capture technology, and offers a highly stable, high-adsorption-capacity material solution for flue gas carbon capture in industries such as power and chemical, thus contributing to industrial low-carbon emission reduction and green development.
[0035] The above-mentioned solution will be further described below with reference to specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments; the implementation conditions used in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.
[0036] Unless otherwise specified in the following examples, all raw materials are commercially available or prepared by conventional methods in the art.
[0037] Cobalt nitrate hexahydrate was purchased from Sinopharm Chemical Reagent Co., Ltd., grade 10007316; potassium hydroxide was purchased from Sinopharm Chemical Reagent Co., Ltd., grade 10017018; anhydrous ethanol was purchased from Shanghai Titan Technology Co., Ltd., grade 012898003; boric acid was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., grade B111592; and carbon cloth was purchased from Shengernuo Energy Mall, grade hydrophilic WOS1011.
[0038] Example 1: This example provides a carbon dioxide adsorbent material and its preparation method. The preparation method includes: dissolving cobalt nitrate hexahydrate and boric acid in 50 mL of deionized water, stirring until completely dissolved, and preparing an electrolyte (the concentration of cobalt nitrate hexahydrate is 0.05 mol·L⁻¹). -1 The concentration of boric acid is 0.2 mol·L⁻¹. -1 A 1 cm × 1 cm piece of carbon cloth was cut as the working electrode, a saturated calomel electrode as the reference electrode, and a graphite rod as the counter electrode. A working voltage of -1.2 V (vs. SCE) was applied for electrodeposition for 500 seconds. After the reaction, the carbon cloth was washed with deionized water until the pH of the carbon cloth was 7, and then washed three times with anhydrous ethanol. The carbon cloth-supported cyclic cobalt hydroxyl oxide precursor was dried to obtain the carbon cloth-supported precursor. Prepare 0.5 mol·L -1The carbon cloth-supported cyclic cobalt hydroxyl oxide precursor obtained in the previous step was immersed in a dilute alkaline solution of potassium hydroxide and stirred at room temperature for 12 hours. After the reaction was completed, it was washed three times each with deionized water and anhydrous ethanol, and dried to obtain the carbon cloth-supported cyclic cobalt hydroxyl oxide carbon dioxide adsorbent material prepared by electrodeposition method, which can also be referred to as carbon dioxide adsorbent material.
[0039] Example 2: This example provides a carbon dioxide adsorbent material and its preparation method. The preparation method includes: dissolving cobalt nitrate hexahydrate and boric acid in 50 mL of deionized water, stirring until completely dissolved, and preparing an electrolyte (the concentration of cobalt nitrate hexahydrate is 0.05 mol·L⁻¹). -1 The concentration of boric acid is 0.4 mol·L⁻¹. -1 A 1 cm × 1 cm piece of carbon cloth was cut as the working electrode, a saturated calomel electrode as the reference electrode, and a graphite rod as the counter electrode. A working voltage of -1.2 V (vs. SCE) was applied for electrodeposition for 600 seconds. After the reaction, the carbon cloth was washed with deionized water until the pH of the carbon cloth was 7, and then washed three times with anhydrous ethanol. The carbon cloth-supported cyclic cobalt hydroxyl oxide precursor was dried to obtain the carbon cloth-supported precursor. Prepare 0.7 mol·L -1 The carbon cloth-supported cyclic cobalt hydroxyl oxide precursor obtained in the previous step was immersed in a dilute alkaline solution of potassium hydroxide and stirred at room temperature for 12 hours. After the reaction was completed, it was washed three times each with deionized water and anhydrous ethanol, and dried to obtain the carbon cloth-supported cyclic cobalt hydroxyl oxide carbon dioxide adsorbent material prepared by electrodeposition method, which can also be referred to as carbon dioxide adsorbent material.
[0040] Example 3: This example provides a carbon dioxide adsorbent material and its preparation method. The preparation method includes: dissolving cobalt nitrate hexahydrate and boric acid in 50 mL of deionized water, stirring until completely dissolved, and preparing an electrolyte (the concentration of cobalt nitrate hexahydrate is 0.05 mol·L⁻¹). -1 The concentration of boric acid is 0.4 mol·L⁻¹. -1 A 1 cm × 1 cm piece of carbon cloth was cut as the working electrode, a saturated calomel electrode as the reference electrode, and a graphite rod as the counter electrode. A working voltage of -1.15 V (vs. SCE) was applied for electrodeposition for 600 seconds. After the reaction, the carbon cloth was washed with deionized water until the pH of the carbon cloth was 7, and then washed three times with anhydrous ethanol. The carbon cloth-supported cyclic cobalt hydroxyl oxide precursor was dried to obtain the carbon cloth-supported precursor. Prepare 0.5 mol·L -1The carbon cloth-supported cyclic cobalt hydroxyl oxide precursor obtained in the previous step was immersed in a dilute alkaline solution of potassium hydroxide and stirred at room temperature for 14 hours. After the reaction was completed, it was washed three times each with deionized water and anhydrous ethanol, and dried to obtain the carbon cloth-supported cyclic cobalt hydroxyl oxide carbon dioxide adsorbent material prepared by electrodeposition method, which can also be referred to as carbon dioxide adsorbent material.
[0041] Comparative Example 1: This example provides a carbon dioxide adsorbent material and its preparation method. The preparation method includes: dissolving cobalt nitrate hexahydrate and boric acid in 50 mL of deionized water, stirring until completely dissolved, and preparing an electrolyte (the concentration of cobalt nitrate hexahydrate is 0.05 mol·L⁻¹). -1 The concentration of boric acid is 0.2 mol·L⁻¹. -1 A 1 cm × 1 cm piece of carbon cloth was cut as the working electrode, a saturated calomel electrode as the reference electrode, and a graphite rod as the counter electrode. A working voltage of -1.8 V (vs. SCE) was applied for electrodeposition for 500 seconds. After the reaction was completed, the carbon cloth was washed with deionized water until the pH of the carbon cloth was 7, and then washed three times with anhydrous ethanol and dried to obtain the intermediate. Prepare 0.5 mol·L -1 The intermediate obtained in the previous step was immersed in a dilute alkaline solution of potassium hydroxide and stirred at room temperature for 12 hours. After the reaction was completed, it was washed three times each with deionized water and anhydrous ethanol, and then dried to obtain the carbon dioxide adsorbent material.
[0042] Comparative Example 2: This example provides a carbon dioxide adsorbent material and its preparation method. The preparation method includes: using cobalt nitrate hexahydrate as the cobalt source (0.582 g), sodium hydroxide (NaOH) as the alkali source (0.32 g), sodium dodecyl sulfate (SDS) as the surfactant (0.0144 g), and deionized water (30 mL) as the reaction solvent; first, add 30 mL of deionized water to a beaker, then add cobalt nitrate and SDS sequentially, and stir magnetically for 30 minutes until completely dissolved to form a homogeneous pink solution; then, while stirring, slowly add 10 mL of deionized water containing 0.32 g NaOH, and the solution gradually turns brownish-brown. Continue stirring for 15 minutes to ensure that the system is mixed evenly. The above mixture was transferred to a 50 mL polytetrafluoroethylene-lined reactor, sealed, and placed in an oven for constant temperature reaction at 120 °C for 12 hours. After the reaction was completed, the reactor was allowed to cool naturally to room temperature. The product in the liner was removed and washed four times by alternating centrifugation with deionized water and anhydrous ethanol to remove unreacted impurities. Finally, the washed product was placed in a vacuum drying oven at 60 °C and dried for 8 hours to obtain cobalt hydroxyoxide nanosheets.
[0043] Mechanically loaded cobalt hydroxyoxide nanosheets on carbon cloth were prepared by the drop-drop method: a 1 cm × 1 cm piece of carbon cloth was cut and laid flat on a glass slide. 100 μL of 0.5 g / L ethanol-cobalt hydroxyoxide suspension (prepared by dispersing cobalt hydroxyoxide nanosheets in ethanol) was dropped onto the carbon cloth and dried in a vacuum drying oven at 60 °C for 4 hours to obtain the mechanically loaded cobalt hydroxyoxide carbon dioxide adsorbent material on carbon cloth.
[0044] Comparative Example 3: This example provides a carbon dioxide adsorbent material and its preparation method. The preparation method is basically the same as in Example 1, except that boric acid is not added to the electrolyte.
[0045] Performance testing: The material was placed in a fixed-bed adsorption apparatus for carbon dioxide adsorption-desorption performance testing. The fixed-bed reactor was a high-temperature resistant glass tube with an inner diameter of 5 mm, an outer diameter of 10 mm, and a length of 200 mm, equipped with a precision temperature control device on the outside. The reaction temperature deviation was less than ±0.5 ℃, and both ends of the reactor were filled with ultrafine glass wool to reduce adsorbent loss during the test.
[0046] Take 1.0 g of the materials obtained in Examples 1-3 and Comparative Examples 1-3, and uniformly fill them into a fixed-bed reactor. First, the adsorbent is added at 100 mL / min. -1 The adsorbent was pretreated by heating at 373 K for 1 hour under a high-purity N2 atmosphere to remove impurities. After the reactor cooled to the required experimental temperature (333 K) and stabilized, the gas path was switched to 100 mL / min. -1 A CO2 adsorption experiment was conducted using simulated flue gas containing 10% CO2. The CO2 concentration at the fixed bed outlet was measured using a CO2 analyzer. Adsorption saturation was indicated when the outlet CO2 concentration equaled the inlet concentration. A breakthrough curve was plotted based on the change in CO2 concentration at the fixed bed outlet over different time periods. The CO2 adsorption capacity was calculated by integrating the area under the breakthrough curve using conditions such as CO2 inlet concentration and flow rate. The integral calculation formula is shown below.
[0047] ; Where Q is the amount of CO2 adsorbed by the adsorbent (mmol·g) -1 m is the mass of the adsorbent (g), and v is the inlet gas flow rate (mL·min). -1 C0 represents the CO2 concentration at the inlet of the fixed-bed reactor (vol.%), C represents the CO2 concentration at the outlet of the fixed-bed reactor (vol.%), t represents the adsorption time (s), P represents the experimental operating pressure (kPa), T represents the experimental temperature (K), and R represents the gas constant (8.314 J·mol⁻¹). -1 ·K -1 ).
[0048] Desorption performance and cycling stability were then tested. After adsorption was complete, the gas flow was switched to 100 mL / min. -1 The CO2 was heated to 403 K for desorption experiments. When the CO2 concentration at the fixed bed outlet was 0, it proved that the adsorbent had been regenerated. This CO2 adsorption / desorption experiment was repeated multiple times to examine the cyclic stability of the adsorbent.
[0049] (1) Figure 1 The images show scanning electron microscope (SEM) images of the carbon dioxide adsorbent material prepared in Example 1 of this invention at different magnifications. From these SEM images, a large number of uniformly distributed ring structures can be observed, with ring sizes on the nanoscale (the diameter of the rings is approximately several hundred nanometers, as determined by the scale bar). This ring morphology has two major advantages: firstly, it significantly increases the specific surface area of the material, providing abundant physical adsorption sites for CO2 adsorption; secondly, the openness of the ring structure facilitates the diffusion and contact of CO2 molecules, combining with the hydroxyl groups on the CoOOH surface and Co... 3+ Active sites can further enhance chemisorption, thereby improving CO2 adsorption performance; (2) Figure 2 The image shows the powder X-ray diffraction (XRD) pattern of the carbon dioxide adsorbent material prepared in Example 1 of this invention. As can be seen from the image, except for the C characteristic peak (carbon cloth) at around 2θ=26°, the diffraction peaks of the sample correspond one-to-one with the characteristic peaks of the standard card (PDF07-1069) of cobalt hydroxyoxide (CoOOH), and there are no obvious impurity peaks. This indicates that the method successfully prepared high-purity CoOOH crystals, and the crystal structure completely matches the target phase, providing direct evidence for the chemical composition and crystal structure of the material. (3) The specific surface area data of different adsorbent materials are shown in Table 1.
[0050] Table 1
[0051] As shown in Table 1, the three examples have higher specific surface areas. This is attributed to the use of electrodeposition combined with alkaline treatment in these examples to prepare cyclic cobalt hydroxyl oxide structures. These nanorings have hollow, thin-walled morphologies, significantly increasing the specific surface area of the material (90-98 μm²). 2 ·g -1 In contrast, in Comparative Example 1, the electrodeposition voltage was too high (-1.8V), which may have disrupted the ring morphology of the material, leading to a decrease in specific surface area (75 μm). 2 ·g -1 Comparative Example 2: Nanosheets were prepared by hydrothermal method and mechanically loaded onto carbon cloth. The material structure was dense, and the loading method easily led to agglomeration, with a specific surface area of only 50 m².2 ·g -1 In Comparative Example 3, without boric acid, the pH of the electrolyte was unstable, resulting in disordered morphology of the cobalt hydroxyoxide precursor. It failed to form a uniform ring structure, instead producing only irregular particles and plate-like aggregates, significantly reducing the specific surface area to 62 m². 2 ·g -1 .
[0052] (4) The adsorption capacity and cycle stability data of different adsorbent materials are shown in Table 2.
[0053] Table 2
[0054] As shown in Table 2, the CO2 adsorption performance and cycle stability of Examples 1-3 and Comparative Examples 1-3 exhibit significant differences, as detailed below: Example 1: Initial CO2 adsorption capacity 3.0 mmol·g -1 After 10 cycles, the concentration was 2.6 mmol / g. -1 (Retention rate approximately 86.7%). The advantage stems from the cyclic cobalt hydroxyl oxide structure prepared by electrodeposition, and its high specific surface area (98 m²). 2 ·g -1 It provides abundant physical adsorption sites, and its ring morphology facilitates CO2 diffusion. The surface hydroxyl groups interact with Co. 3+ The active sites enhance chemical adsorption, and the process stability ensures minimal structural damage after cycling.
[0055] Example 2: Initial 2.9 mmol·g -1 After 10 cycles, the concentration was 2.5 mmol / g. -1 (Retention rate approximately 86.2%). Performance was slightly lower than in Example 1, which is believed to be due to the lower boric acid concentration (0.4 mol·L⁻¹). -1 Adjusting the electrodeposition time (600 s) caused some of the ring structures to agglomerate, reducing the specific surface area (90 m²). 2 ·g -1 The rate was slightly lower, but the core processes of electrodeposition and dilute alkali treatment still ensured the stability of the ring structure, and the cycle retention rate was still significantly better than that of the comparative example.
[0056] Example 3: Initial 3.1 mmol·g -1 After 10 cycles, the concentration was 2.8 mmol·g. -1 (Retention rate approximately 90.3%). The adsorption capacity and cycling stability are outstanding. Analysis suggests this may be due to the adjustment of the electrodeposition voltage (-1.15V) leading to a more uniform ring structure size, and the extension of the dilute alkali treatment time to 14 hours improving the material's crystallinity and structural integrity. The specific surface area (92m²) is also noteworthy. 2 ·g -1The adsorption sites of the ) have good dispersion and low structural loss during cycling.
[0057] Comparative Example 1: Initial 2.5 mmol·g -1 After 10 cycles, the concentration was 1.5 mmol / g. -1 (Retention rate 60%). Analysis suggests that the excessively high electrodeposition voltage (-1.8V) may have disrupted the ring morphology, leading to a decrease in specific surface area (75µm). 2 ·g -1 Furthermore, it has poor structural stability, and adsorption sites are continuously lost during cycling.
[0058] Comparative Example 2: Initial dose 2.1 mmol·g -1 After 10 cycles, the concentration was 0.9 mmol·g. -1 (Retention rate approximately 42.9%). The worst performance is attributed to the use of a hydrothermal method to prepare the nanosheets followed by mechanical loading, resulting in dense nanosheets that are prone to aggregation and have a low specific surface area (50 m²). 2 ·g -1 Mechanical loading methods are prone to detachment during cycling, resulting in a significant loss of active sites.
[0059] Comparative Example 3: Initial CO2 adsorption capacity 2.3 mmol·g -1 After 10 cycles, the concentration was 1.1 mmol / g. -1 (Retention rate 47.8%), specific surface area 62 m² 2 ·g -1 The performance was significantly inferior to that of the previous example. Analysis suggests that the core reason is the absence of boric acid in the electrolyte, which lacks its pH buffering and morphology regulation functions. During electrodeposition, the local pH changes abruptly, preventing the formation of a ring structure and resulting only in irregular particles and aggregates. This leads to insufficient physical adsorption sites, incomplete crystal structure, and limited exposure of surface active sites, making the structure prone to collapse and loss of active sites during cycling. This confirms the crucial role of boric acid.
[0060] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.
[0061] The endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.
Claims
1. A method for producing a carbon dioxide adsorbing material, characterized by, The preparation method comprises: In the presence of a reference electrode and an electrolyte, an electrochemical deposition occurs on a carbon cloth as a working electrode and a carbon rod as a counter electrode, a precursor of a ring-shaped cobalt oxyhydroxide is generated on the carbon cloth, and an intermediate combined with the carbon cloth and the precursor of the ring-shaped cobalt oxyhydroxide is obtained; the intermediate is immersed in an alkaline solution to generate a carbon dioxide adsorption material; The electrolyte comprises a cobalt salt, boric acid and water. The carbon dioxide adsorption material comprises the carbon cloth and the ring-shaped cobalt oxyhydroxide combined with the carbon cloth.
2. The method of claim 1, wherein the carbon dioxide adsorbent material is prepared by a process comprising: The concentration of the cobalt salt in the electrolyte is 0.01-0.1 mol / L, and the concentration of the boric acid is 0.1-0.5 mol / L; and / or, The cobalt salt comprises a combination of one or more of nitrate, sulfate and halide of divalent cobalt ions, and further, the cobalt salt comprises a combination of one or more of cobalt nitrate, cobalt sulfate and cobalt chloride.
3. The method of claim 1, wherein the carbon dioxide adsorbent material is prepared by a process comprising: The reference electrode is a saturated calomel electrode, and / or the counter electrode is a graphite rod, and / or the carbon cloth is a hydrophilic carbon cloth.
4. The method of claim 1, wherein the carbon dioxide adsorbent material is prepared by a process comprising: The working voltage of the electrochemical deposition is controlled to be -1.1~-1.4 V vs. SCE, and / or the time of the electrochemical deposition is controlled to be 400-800 seconds.
5. The method of claim 1, wherein the carbon dioxide adsorbent material is prepared by a process comprising: The concentration of the alkaline solution is 0.5-1 mol / L, and / or the process of immersing the intermediate in the alkaline solution is controlled to be carried out at 20-30°C, and / or the alkaline solution is an aqueous sodium hydroxide solution and / or an aqueous potassium hydroxide solution, and / or the time of immersing the intermediate in the alkaline solution is controlled to be 8-24 hours, and further, 12-16 hours.
6. A carbon dioxide adsorption material prepared by the preparation method of the carbon dioxide adsorption material according to any one of claims 1-5.
7. The carbon dioxide adsorbent material of claim 6, wherein, The specific surface area of the carbon dioxide adsorbent material is equal to or greater than 90 m 2 / g, further 90-120 m 2 / g, and further 90-105 m 2 / g; and / or, the size of the ring-shaped cobalt oxyhydroxide in the carbon dioxide adsorbent material is equal to or less than 800 nm, further equal to or less than 600 nm.
8. A supported, cyclic cobalt oxyhydroxide carbon dioxide adsorbent material, characterized by, The carbon dioxide adsorption material comprises the carbon cloth and the ring-shaped cobalt oxyhydroxide combined with the carbon cloth, and the ring-shaped cobalt oxyhydroxide is sequentially formed by electro-deposition and alkaline etching, and the electro-deposition is carried out in the presence of a divalent cobalt salt, boric acid and a reference electrode.
9. The supported cobalt oxide carbon dioxide adsorbent material of claim 8, wherein, The crystal form of the ring-shaped cobalt oxyhydroxide is consistent with the crystal form of the standard card PDF 07-1069 of cobalt oxyhydroxide.
10. Use of the carbon dioxide adsorption material according to claim 6 or 7, or the supported ring-shaped cobalt oxyhydroxide carbon dioxide adsorption material according to claim 8 or 9 in carbon dioxide adsorption.