Water purification catalyst and preparation process and system thereof

Abstract

The invention discloses a water purification catalyst and a preparation process and system thereof, and belongs to the technical field of water treatment catalytic materials. The catalyst structurally comprises single-layer MXene serving as a conductive framework and a carrier layer, Fe / Co bimetallic phosphide nanoparticles serving as a high-activity catalytic site layer and a nitrogen-doped carbon layer serving as a physical and chemical protection layer. According to the gradient structure design, the high conductivity and abundant surface chemistry of MXene, the efficient synergistic catalytic effect of bimetallic phosphide and the stable protection effect of a carbon layer are fully utilized, and the pollutant degradation efficiency, the cycle stability and the metal ion immobilization capacity of the catalyst are remarkably improved; the technical bottleneck that the activity of a traditional catalyst is reduced too fast in the using process is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of water treatment catalytic materials technology, and specifically to a water purification catalyst, its preparation process, and its system. Background Technology

[0002] With rapid industrialization and urbanization, the types and concentrations of organic pollutants in water bodies are increasing daily, making traditional water treatment methods insufficient to meet the demands for efficient and deep purification. Advanced oxidation technologies have attracted significant attention due to their ability to generate highly reactive oxidizing species and completely degrade pollutants, with the core being the development of high-performance catalysts. However, existing catalysts, especially heterogeneous catalysts, generally suffer from a prominent bottleneck in practical water treatment applications: their activity declines too rapidly during use. This deactivation severely restricts the long-term operational stability and economic viability of the catalyst, increases replacement frequency and operating costs, and becomes a key obstacle to its engineering application in this field.

[0003] The decline in catalyst activity mainly stems from the following mechanisms: First, irreversible deactivation of active sites. In complex real-world water bodies, the catalyst surface is easily covered and poisoned by intermediate products, inorganic ions, or natural organic matter, leading to the masking of active sites or blockage of reaction pathways. Second, the dissolution and loss of active components. Especially for metal-based catalysts under oxidizing or acidic conditions, metal ions are easily leached into the water, not only causing a decrease in activity but also potentially triggering secondary pollution. Third, the instability of the support structure. Under long-term hydraulic shear, temperature fluctuations, or chemical erosion, the support may collapse, aggregate, or corrode, resulting in a decrease in the dispersion of the active phase, a reduction in specific surface area, and a decrease in mass transfer efficiency. In addition, the degradation of electron transport pathways also weakens the catalyst's redox cycle efficiency, preventing it from continuously generating sufficient reactive oxygen species.

[0004] To address the aforementioned issues, researchers have explored various strategies to improve catalyst stability, such as developing novel support materials, constructing core-shell structures, and performing surface modification or doping. However, these methods often struggle to balance activity, stability, and cost: either the excessively thick protective layer sacrifices accessibility to active sites, weak interfacial bonding prevents long-term effective fixation of active components, or complex preparation processes hinder scalability. Therefore, there is an urgent need for a novel catalyst design approach and controllable preparation process capable of precisely constructing a gradient composite structure of "conductive framework-highly active sites-robust protective layer" at the molecular / nanoscale, fundamentally synergistically enhancing catalyst activity, stability, and lifetime to meet the demands for efficient, long-lasting, and safe water purification. Summary of the Invention

[0005] To overcome the above-mentioned defects of the prior art, embodiments of the present invention provide a water purification catalyst, its preparation process and system, which solves the problem of the catalyst activity decreasing too quickly during use.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A water purification catalyst, characterized in that it comprises a conductive framework and support layer, a highly active catalytic site layer, and a physicochemical protective layer.

[0007] Preferably, the conductive framework and the carrier layer are single layers. The highly active catalytic site layer is composed of Fe / Co bimetallic phosphide nanoparticles, and the physicochemical protective layer is a nitrogen-doped carbon layer.

[0008] A process for preparing a water purification catalyst includes the following steps: S1: LiF is dissolved in HCl to prepare the etching solution, and then the following additives are added to the etching solution. The powder is heated and mixed at 35-40°C and stirred continuously at 500 rpm for 24 hours to produce a multilayered product. ; S2: Multi-layer Rinse with deionized water until the pH of the supernatant is 7, then run multiple layers. The mixture was dispersed in deionized water and sonicated. The mixture was then centrifuged at 2000 rpm for 2 minutes, and the supernatant was collected to obtain a monolayer. The nanocolloid dispersion was finally freeze-dried to obtain MXene; S3: The preparation obtained in S2 MXene was dispersed in deionized water to form a uniform dispersion, and then added... , Then, it was continuously stirred to obtain adsorbed metal cations. ; S4: Adsorbs metal cations Centrifuge to extract the supernatant, disperse, dry, and then... The powder is placed downstream of the tube furnace to adsorb metal cations. The sample was placed upstream and then heated in a tube furnace under an argon atmosphere at a heating rate of 2-5℃ / min to 300-350℃, and held at that temperature for 2 hours to obtain... @A-TMP; S5: Will @A-TMP was uniformly dispersed in Tris-HCl buffer, and 1 mg / mL dopamine hydrochloride was added. The mixture was stirred at room temperature for 12 hours to obtain... @A-TMP@PDA mixture; S6: Will The A-TMP-PDA mixture was collected by centrifugation at 1000 rpm. @A-TMP@PDA, then heated and held at a temperature under an argon atmosphere. @A-TMP@NC gradient catalyst.

[0009] Preferably, in S1, LiF is dissolved in 6M HCl at 0°C.

[0010] Preferably, in S2, Disperse in deionized water and ultrasonically disperse at a frequency of 50 kHz for 1 hour.

[0011] Preferably, in S3, MXene , Disperse evenly in deionized water and place at 25°C with continuous stirring at 500-1000 rpm for 2 hours.

[0012] Preferably, in S4, the adsorbed metal cations are... Centrifuge at 1500-2000 rpm for 2-5 minutes.

[0013] Preferably, in S5 @A-TMP was uniformly dispersed in 10mM Tris-HCl buffer at pH 8.5.

[0014] Preferably, centrifugal collection is performed in S6. The @A-TMP@PDA was heated to 600-700℃ in an argon atmosphere at a heating rate of 5℃ / min.

[0015] A system for preparing a water purification catalyst includes a precursor preparation and etching unit, a washing and stripping unit, an ion adsorption and loading unit, a gas-phase phosphating treatment unit, a polymer coating unit, a high-temperature carbonization and post-treatment unit, and a central control and material conveying unit. The precursor preparation and etching unit includes an acidification reactor, a precision metering pump, a temperature controller, and a high-speed stirrer, used to prepare the etching solution; The washing and stripping unit includes a multi-stage centrifugal washer, an ultrasonic dispersion tank, a vacuum freeze dryer, and an online pH meter, used for washing, freezing, and drying to obtain... powder; The ion adsorption and loading unit includes a constant-temperature stirred adsorption reactor, a precision liquid feeding system, and a centrifuge, used to prepare ions adsorbed with metal cations. intermediate; The gas-phase phosphating unit includes a tubular atmosphere furnace system, a powder feeder, a temperature control system, an argon gas path and flow controller, used for preparing... @A-TMP; The polymer coating unit includes a buffer preparation and constant temperature stirred reactor, a pH meter, and a liquid feed pump, which are used to connect to a centrifuge and perform solid-liquid separation. The high-temperature carbonization and post-processing unit includes a second tubular atmosphere furnace system, a crucible or quartz boat, an inert gas protection system, and a temperature control program, used to prepare the final catalyst. @A-TMP@NC; The central control and material conveying unit includes a programmable logic controller, a distributed control system, a sensor network, pipelines, and a pump and valve system, which are used to integrate and control the operation of the entire system. The precursor preparation and etching unit and the washing and stripping unit are connected by a corrosion-resistant pump and a closed pipeline; the washing and stripping unit and the ion adsorption and loading unit are connected by a pneumatic conveying system or a closed screw feeder under inert gas protection; the ion adsorption and loading unit and the gas phase phosphating unit are connected by a vacuum conveyor belt or a closed bucket elevator; the gas phase phosphating unit and the polymer coating unit are connected by a mechanical conveying device under inert atmosphere protection; the polymer coating unit and the high-temperature carbonization and post-treatment unit are connected by a high-temperature resistant conveyor belt.

[0016] The technical effects and advantages of the water purification catalyst, its preparation process, and the system of this invention are as follows: 1. This invention utilizes a LiF / HCl system to... By selectively etching the precursor to precisely remove the Al atomic layer while preserving the Ti-C framework and introducing surface functional groups such as -OH and -F, multilayer substrates were successfully fabricated. MXene, this step lays the foundation for the subsequent construction of a highly conductive and high specific surface area support, endowing the material with excellent electronic conductivity and abundant surface adsorption sites, and solving the problems of poor conductivity and uneven loading of active sites in traditional supports.

[0017] 2. This invention, through ultrasonic-assisted liquid phase stripping and centrifugal fractionation, separates multilayer... The process efficiently transforms the nanosheets into single-layer or few-layer nanosheets, significantly increasing the specific surface area and active interface of the material. The freeze-drying process avoids the recombination of nanosheets due to surface tension, preserving their porous structure and surface properties. This step significantly improves the mass transfer efficiency and active site exposure of the catalyst, enhancing the subsequent adsorption capacity and uniformity of metal ions.

[0018] 3. This invention utilizes The abundant negatively charged functional groups on the surface of MXene enable efficient and uniform adsorption through electrostatic interactions. and Metal cations. This step achieves molecular-level dispersion of the active metal precursor on the support surface, avoiding the agglomeration phenomenon commonly found in traditional impregnation methods. This provides a key prerequisite for the subsequent formation of highly dispersed, small-sized bimetallic phosphide nanoparticles, ensuring high efficiency and stability of catalytic activity.

[0019] 4. This invention, under an inert atmosphere, through... thermal decomposition The gas reacts with Fe / Co ions adsorbed on the support in a gas-solid phase reaction, generating Fe / Co bimetallic phosphide nanoparticles in situ. This step directly constructs highly active catalytic centers on the conductive framework, generating a significant electronic synergistic effect between the two metals. This optimizes the catalyst's adsorption activation energy for pollutants, significantly improving the redox reaction rate and degradation efficiency.

[0020] 5. In this invention, dopamine undergoes a self-polymerization reaction in a weakly alkaline buffer solution. A polydopamine film is uniformly coated onto the surface of the @A-TMP@PDA layer. This PDA layer not only bonds tightly to the underlying layer through strong adhesion and abundant functional groups, but also serves as a precursor for the nitrogen-doped carbon layer. This step provides initial physical isolation and chemical stabilization for the active core, preventing sintering or loss during subsequent high-temperature processing or use.

[0021] 6. This invention involves high-temperature heat treatment of the PDA-coated intermediate in an inert atmosphere, carbonizing the PDA into a nitrogen-doped carbon layer. This carbon layer has a dense structure and high chemical inertness, effectively isolating the active sites from harmful substances in the aqueous phase, and greatly inhibiting the leaching of metal ions and the deactivation of the active phase. Simultaneously, nitrogen doping further optimizes the electronic structure of the carbon layer, enhancing its electronic coupling with the underlying MXene and phosphides, constructing a gradient stable structure integrating the conductive carrier, active center, and protective layer, achieving a perfect balance between high activity and long lifetime. Attached Figure Description

[0022] Figure 1 This is a flowchart of a water purification catalyst, its preparation process, and its system proposed in this invention. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0025] Example 1 This embodiment provides a water purification catalyst, its preparation process, and a system thereof, the specific implementation steps of which include: Experimental materials: LiF, HCl, 10mM 10mM , Dopamine hydrochloride, Tris-HCl.

[0026] Experimental objective: A method for preparing a water purification catalyst.

[0027] Experimental steps: S1: An etching solution was prepared by dissolving LiF in 6M HCl at 0°C. Then, [the following text appears to be unrelated and possibly a separate sentence fragment:] Add […]. The powder is heated and mixed at 35-40°C and stirred continuously at 500 rpm for 24 hours to produce a multilayered product. ; S2: Multi-layer Rinse with deionized water until the pH of the supernatant is 7, then run multiple layers. The mixture was dispersed in deionized water and sonicated in an argon atmosphere at 50 kHz for 1 hour. The mixture was then centrifuged at 2000 rpm for 2 minutes, and the supernatant was collected to obtain a monolayer. The nanocolloid dispersion was finally freeze-dried to obtain MXene; S3: The preparation obtained in S2 MXene was dispersed in deionized water to form a uniform dispersion, and then added... , Then, it was placed in an environment of 25°C and stirred continuously at 500 rpm for 2 hours to obtain adsorbed metal cations. ; S4: Adsorbs metal cations Centrifuge at 1500 rpm for 2 minutes and extract the supernatant, disperse, dry, and then... The powder is placed downstream of the tube furnace to adsorb metal cations. The sample was placed upstream and then heated in a tube furnace under an argon atmosphere at a heating rate of 2-5℃ / min to 300-350℃, and held at that temperature for 2 hours to obtain... @A-TMP; S5: Will @A-TMP was uniformly dispersed in 10mM Tris-HCl buffer at pH 8.5, and 1 mg / mL dopamine hydrochloride was added. The mixture was stirred at room temperature for 12 hours to obtain... @A-TMP@PDA mixture; S6: Will The A-TMP-PDA mixture was collected by centrifugation at 1000 rpm. @A-TMP@PDA, then placed in an argon atmosphere and heated to 600-700℃ at a heating rate of 5℃ / min and held for 2 hours. @A-TMP@NC gradient catalyst.

[0028] Experimental results: See Table 1 for details.

[0029] Table 1: Test Results of Example 1

[0030] Example 1 uses Using MXene as a carrier, a highly active phosphide phase is formed by adsorbing and phosphating Fe / Co bimetallic ions. Finally, a PDA-derived nitrogen-doped carbon layer is coated onto this phase, constructing a gradient composite structure of conductive carrier-bimetallic phosphide-carbon protective layer. This structure fully utilizes the electronic conductivity advantages of MXene, the synergistic catalytic effect of the bimetallic compounds, and the physicochemical protective effect of the carbon layer, achieving a high degradation rate of 98%, a cycle stability of 95%, and a metal leaching rate of only 2%. This is the optimal embodiment of the present invention, achieving the best balance in terms of activity, stability, and environmental friendliness.

[0031] Example 2 This embodiment provides a water purification catalyst, its preparation process, and a system thereof, the specific implementation steps of which include: Experimental materials: LiF, HCl, graphene, 10mM 10mM , Dopamine hydrochloride, Tris-HCl.

[0032] Experimental objective: Exploring the use of graphene as a substitute The effect of MXene as a support on catalyst performance.

[0033] Experimental steps: S1: Graphene is dispersed in deionized water to form a uniform dispersion, and then added... , Then, it was placed in an environment of 25°C and stirred continuously at 500 rpm for 2 hours to obtain graphene adsorbed with metal cations. S2: Centrifuge the graphene with adsorbed metal cations at 1500 rpm for 2 minutes, extract the supernatant, disperse, and dry. Then... The powder was placed downstream of a tube furnace and the graphene adsorbed with metal cations was placed upstream. The tube furnace was then heated in an argon atmosphere to 300-350°C at a heating rate of 2-5°C / min and held for 2 hours to obtain graphene@A-TMP. S3: Graphene@A-TMP was uniformly dispersed in 10mM Tris-HCl buffer at pH=8.5 and 1mg / mL dopamine hydrochloride was added. The mixture was stirred at room temperature for 12 hours to obtain a graphene@A-TMP@PDA mixture. S4: The graphene@A-TMP@PDA mixture was centrifuged at 1000 rpm to collect graphene@A-TMP@PDA. Then, it was heated to 600-700℃ under an argon atmosphere at a heating rate of 5℃ / min and held for 2 hours to obtain the graphene@A-TMP@NC gradient catalyst.

[0034] Experimental results: See Table 2 for details.

[0035] Table 2: Test Results of Example 2

[0036] In Example 2, the support was replaced with graphene, while retaining the bimetallic phosphide and carbon-coated structure. However, due to the relatively inert surface chemistry of graphene, its ability to adsorb metal precursors and bind to the interface during the phosphating process is weaker than that of MXene. This resulted in a slight decrease in the dispersion of the active phase and the efficiency of interfacial electron transfer, ultimately leading to a slightly lower catalytic performance than in Example 1. This demonstrates the unique advantages of the MXene support in constructing a highly efficient catalytic interface.

[0037] Example 3 This embodiment provides a water purification catalyst, its preparation process, and a system thereof, the specific implementation steps of which include: Experimental materials: LiF, HCl, 10mM , Dopamine hydrochloride, Tris-HCl.

[0038] Experimental objective: To investigate the effect of Fe as a single active metal on catalyst performance.

[0039] Experimental steps: S1: An etching solution was prepared by dissolving LiF in 6M HCl at 0°C. Then, [the following text appears to be unrelated and possibly a separate sentence fragment:] Add […]. The powder is heated and mixed at 35-40°C and stirred continuously at 500 rpm for 24 hours to produce a multilayered product. ; S2: Multi-layer Rinse with deionized water until the pH of the supernatant is 7, then run multiple layers. The mixture was dispersed in deionized water and sonicated in an argon atmosphere at 50 kHz for 1 hour. The mixture was then centrifuged at 2000 rpm for 2 minutes, and the supernatant was collected to obtain a monolayer. The nanocolloid dispersion was finally freeze-dried to obtain MXene; S3: The preparation obtained in S2 MXene was dispersed in deionized water to form a uniform dispersion, and then added... Then, it was placed in an environment of 25°C and stirred continuously at 500 rpm for 2 hours to obtain adsorbed metal cations. ; S4: Adsorbs metal cations Centrifuge at 1500 rpm for 2 minutes and extract the supernatant, disperse, dry, and then... The powder is placed downstream of the tube furnace to adsorb metal cations. The sample was placed upstream and then heated in a tube furnace under an argon atmosphere at a heating rate of 2-5℃ / min to 300-350℃, and held at that temperature for 2 hours to obtain... @A-FeP; S5: Will @A-TMP was uniformly dispersed in 10mM Tris-HCl buffer at pH 8.5, and 1 mg / mL dopamine hydrochloride was added. The mixture was stirred at room temperature for 12 hours to obtain... @A-TMP@PDA mixture; S6: Will The A-FeP@PDA mixture was collected by centrifugation at 1000 rpm. @A-FeP@PDA was then heated to 600-700℃ in an argon atmosphere at a heating rate of 5℃ / min and held for 2 hours. @A-FeP@NC gradient catalyst.

[0040] Experimental results: See Table 3 for details.

[0041] Table 3: Test Results of Example 3

[0042] Example 3, based on Example 1, uses only Fe as the single active metal, omitting the introduction of Co. While retaining the MXene support and carbon coating structure, it lacks the redox synergy between the Fe / Co bimetals, resulting in a limited degradation pathway for pollutants, reduced efficiency in reactive oxygen species generation, and a degradation rate decreasing to 85%.

[0043] Example 4 This embodiment provides a water purification catalyst, its preparation process, and a system thereof, the specific implementation steps of which include: Experimental materials: LiF, HCl, 10mM 10mM Dopamine hydrochloride, Tris-HCl.

[0044] Experimental objective: The impact of omitting the phosphating step on catalyst performance.

[0045] Experimental steps: S1: An etching solution was prepared by dissolving LiF in 6M HCl at 0°C. Then, [the following text appears to be unrelated and possibly a separate sentence fragment:] Add […]. The powder is heated and mixed at 35-40°C and stirred continuously at 500 rpm for 24 hours to produce a multilayered product. ; S2: Multi-layer Rinse with deionized water until the pH of the supernatant is 7, then run multiple layers. The mixture was dispersed in deionized water and sonicated in an argon atmosphere at 50 kHz for 1 hour. The mixture was then centrifuged at 2000 rpm for 2 minutes, and the supernatant was collected to obtain a monolayer. The nanocolloid dispersion was finally freeze-dried to obtain MXene; S3: The preparation obtained in S2 MXene was dispersed in deionized water to form a uniform dispersion, and then added... , Then, it was placed in an environment of 25°C and stirred continuously at 500 rpm for 2 hours to obtain adsorbed metal cations. ; S4: Will @A-TMP was uniformly dispersed in 10mM Tris-HCl buffer at pH 8.5, and 1 mg / mL dopamine hydrochloride was added. The mixture was stirred at room temperature for 12 hours to obtain... @A-TMP@PDA mixture; S5: Will The PDA mixture was collected by centrifugation at 1000 rpm. @PDA, and then heated to 600-700℃ in an argon atmosphere at a heating rate of 5℃ / min and held for 2 hours to obtain a gradient catalyst.

[0046] Experimental results: See Table 4 for details.

[0047] Table 4: Test Results of Example 4

[0048] In Example 4, the phosphating step was omitted in the preparation process; the Fe / Co ions adsorbed on MXene were directly carbon-coated. Because a highly active phosphide phase was not formed, the catalyst's redox ability was significantly weakened, and the metal species were not firmly bonded to the support, resulting in a significant decrease in activity, a reduction in specific surface area, and an increase in metal leaching rate. This demonstrates the necessity of phosphide as the core active phase.

[0049] Example 5 This embodiment provides a water purification catalyst, its preparation process, and a system thereof, the specific implementation steps of which include: Experimental materials: LiF, HCl, 10mM 10mM , Tris-HCl.

[0050] Experimental objective: The effect of omitting the polydopamine coating and carbonization steps on catalyst stability was investigated.

[0051] Experimental steps: S1: An etching solution was prepared by dissolving LiF in 6M HCl at 0°C. Then, [the following text appears to be unrelated and possibly a separate sentence fragment:] Add […]. The powder is heated and mixed at 35-40°C and stirred continuously at 500 rpm for 24 hours to produce a multilayered product. ; S2: Multi-layer Rinse with deionized water until the pH of the supernatant is 7, then run multiple layers. The mixture was dispersed in deionized water and sonicated in an argon atmosphere at 50 kHz for 1 hour. The mixture was then centrifuged at 2000 rpm for 2 minutes, and the supernatant was collected to obtain a monolayer. The nanocolloid dispersion was finally freeze-dried to obtain MXene; S3: The preparation obtained in S2 MXene was dispersed in deionized water to form a uniform dispersion, and then added... , Then, it was placed in an environment of 25°C and stirred continuously at 500 rpm for 2 hours to obtain adsorbed metal cations. ; S4: Adsorbs metal cations Centrifuge at 1500 rpm for 2 minutes and extract the supernatant, disperse, dry, and then... The powder is placed downstream of the tube furnace to adsorb metal cations. The sample was placed upstream and then heated in a tube furnace under an argon atmosphere at a heating rate of 2-5℃ / min to 300-350℃, and held at that temperature for 2 hours to obtain... @A-TMP.

[0052] Experimental results: See Table 5 for details.

[0053] Table 5: Test Results of Example 5

[0054] Example 5 omitted the PDA coating and carbonization steps, and only prepared @A-TMP phosphide materials. Although the initial activity is high, the lack of carbon layer protection makes the active phase prone to dissolution, loss, or poisoning during the reaction, leading to a sharp decline in cycle stability and a metal leaching rate as high as 14%, highlighting the key role of the carbon coating layer in maintaining the long-term stability of the catalyst.

[0055] Comparative Example 1 This embodiment provides a method for preparing a traditional water purification catalyst, the specific implementation steps of which include: Experimental materials: Tetrabutyl titanate, anhydrous ethanol, ferric nitrate, deionized water, and ammonia.

[0056] Experimental objective: A conventional catalyst is provided as a performance benchmark.

[0057] Experimental steps: S1: Dissolve 10 mL of tetrabutyl titanate in 40 mL of anhydrous ethanol and stir magnetically for 30 minutes to form a homogeneous solution A. Separately, mix 5 mL of deionized water with 20 mL of anhydrous ethanol and adjust the pH to 3-4 with ammonia to obtain solution B. Slowly add solution B dropwise to solution A under vigorous stirring and continue stirring for 2 hours to form a transparent sol. Allow the sol to stand and age for 24 hours, then dry it in an oven at 80℃ for 12 hours. Finally, calcine it at 500℃ in air for 3 hours to obtain a white... powder; S2: Prepare a 0.1 M ferric nitrate aqueous solution. Weigh 1.0 g of the solution prepared above. The powder was added to 20 mL of ferric nitrate solution and ultrasonically dispersed at room temperature for 30 minutes, then stirred and evaporated to dryness in a 60°C water bath. S3: The evaporated solid was further dried in an 80℃ oven for 6 hours, then placed in a muffle furnace and heated to 450℃ at a rate of 2℃ / min in air atmosphere, held at that temperature for 3 hours, and allowed to cool naturally to room temperature. The solid was then ground through a 200-mesh sieve to obtain a brownish-red color. catalyst; S4: Before use, the catalyst can be washed three times in deionized water and dried at 100°C for 2 hours to remove loosely attached species on the surface.

[0058] Experimental results: See Table 6 for details.

[0059] Table 6: Test Results of Comparative Example 1

[0060] Comparative Example 1 was prepared using traditional sol-gel and impregnation-calcination processes. The catalyst, with its poor dispersion of active components, weak conductivity of the support, and lack of synergistic effect and protective structure, suffers from overall poor catalytic performance. This fully reveals the limitations of traditional catalysts in material design and structural engineering, and conversely confirms the advanced nature and necessity of the gradient structure design of this invention.

[0061] refer to Figure 1 The flowchart in Example 1 is adopted. Using MXene as a carrier, combined with the gradient structure design of Fe / Co bimetallic phosphide active phase and PDA-derived nitrogen-doped carbon protective layer, it exhibits the best performance in key indicators such as pollutant degradation rate, specific surface area, cycle stability and metal leaching rate, achieving a high degree of unity between activity, stability and environmental friendliness.

[0062] Example 2 uses graphene as a carrier. Although it retains the bimetallic phosphide and carbon coating structure, the degradation rate, specific surface area and cycle stability are all lower than those of Example 1. The data show that the carrier surface has an important influence on the loading of the active phase and the interfacial electron transfer.

[0063] Example 3 uses a single Fe active metal, and the degradation rate is significantly reduced to 85%. Although the specific surface area and stability are still at a good level, the data confirms that the synergy of the two metals can effectively improve the catalytic oxidation efficiency.

[0064] Example 4 uses a simplified process that omits the phosphating step, resulting in a comprehensive decline in catalytic performance. The degradation rate is only 78%, the specific surface area drops to 250 m² / g, and the metal leaching rate is as high as 15%. The data highlight the necessity of phosphides as a highly active phase.

[0065] Example 5 uses a preparation method that omits carbon coating, and although the initial degradation rate is as high as 95% and the specific surface area reaches 400, it still achieves a high initial degradation rate. However, the cycle stability dropped sharply to 65%, and the metal leaching rate reached 14%, proving the key protective role of the carbon layer in long-term stable operation.

[0066] Comparative Example 1 adopts the traditional The catalyst's performance was comprehensively inferior: degradation rate of 60%, specific surface area of ​​only 80 m² / g, stability of 70%, and leaching rate of 12%, clearly reflecting the limitations of traditional catalysts in terms of structure and performance.

[0067] Comparing the embodiments and comparative examples, Example 1 achieves the optimal balance in catalytic activity, structural stability, and metal immobilization capacity. Through a sophisticated gradient synergistic design of a conductive MXene support, a bimetallic phosphide active phase, and a nitrogen-doped carbon protective layer, it significantly improves the overall degradation performance and lifespan of the catalyst, making it suitable for efficient, long-lasting, and environmentally friendly water purification applications. Example 2, although using high-performance carbon materials, suffers from a slight performance decrease due to weak interfacial bonding. Example 3, employing a single metal active center, exhibits insufficient catalytic oxidation capacity. Example 4 suffers from significant performance degradation due to the lack of a highly active phosphide phase. Example 5, while initially showing high activity, suffers from severe stability issues due to the absence of a protective layer. The comparative examples highlight the functional limitations of traditional catalysts, such as low activity and susceptibility to deactivation. Therefore, the gradient composite structure of this invention is a key innovation that overcomes the performance bottlenecks of existing catalysts, providing a new approach for the design of high-performance water purification catalytic materials.

[0068] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of protection of the claims.

[0069] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A water purification catalyst, characterized in that, It includes a conductive framework and support layer, a highly active catalytic site layer, and a physicochemical protective layer.

2. The water purification catalyst as described in claim 1, characterized in that, The conductive framework and carrier layer are single layers. The highly active catalytic site layer is composed of Fe / Co bimetallic phosphide nanoparticles, and the physicochemical protective layer is a nitrogen-doped carbon layer.

3. A water purification catalyst and its preparation process, specifically including the following steps: S1: LiF is dissolved in HCl to prepare the etching solution, and then the following additives are added to the etching solution. The powder is heated and mixed at 35-40°C and stirred continuously at 500 rpm for 24 hours to produce a multilayered product. ; S2: Multi-layer Rinse with deionized water until the pH of the supernatant is 7, then run multiple layers. The mixture was dispersed in deionized water and sonicated. The mixture was then centrifuged at 2000 rpm for 2 minutes, and the supernatant was collected to obtain a monolayer. The nanocolloid dispersion was finally freeze-dried to obtain MXene; S3: The preparation obtained in S2 MXene was dispersed in deionized water to form a uniform dispersion, and then added... , Then, it was continuously stirred to obtain adsorbed metal cations. ; S4: Adsorbs metal cations Centrifuge to extract the supernatant, disperse, dry, and then... The powder is placed downstream of the tube furnace to adsorb metal cations. The sample was placed upstream and then heated in a tube furnace under an argon atmosphere at a heating rate of 2-5℃ / min to 300-350℃, and held at that temperature for 2 hours to obtain... @A-TMP; S5: Will @A-TMP was uniformly dispersed in Tris-HCl buffer, and 1 mg / mL dopamine hydrochloride was added. The mixture was stirred at room temperature for 12 hours to obtain... @A-TMP@PDA mixture; S6: Will The A-TMP-PDA mixture was collected by centrifugation at 1000 rpm. @A-TMP@PDA, then heated and held at a temperature under an argon atmosphere. @A-TMP@NC gradient catalyst.

4. The water purification catalyst and its preparation process as described in claim 3, characterized in that, In S1, LiF is dissolved in 6M HCl at 0°C.

5. The water purification catalyst and its preparation process as described in claim 3, characterized in that, S2 Lieutenant General Disperse in deionized water and ultrasonically disperse at a frequency of 50 kHz for 1 hour.

6. The water purification catalyst and its preparation process as described in claim 3, characterized in that, S3 Lieutenant General MXene , Disperse evenly in deionized water and place at 25°C with continuous stirring at 500-1000 rpm for 2 hours.

7. The water purification catalyst and its preparation process as described in claim 3, characterized in that, S4 will adsorb metal cations Centrifuge at 1500-2000 rpm for 2-5 minutes.

8. The water purification catalyst and its preparation process as described in claim 3, characterized in that, S5 Lieutenant General @A-TMP was uniformly dispersed in 10mM Tris-HCl buffer at pH 8.

5.

9. The water purification catalyst and its preparation process as described in claim 3, characterized in that, S6 will be collected by centrifugation. The @A-TMP@PDA was heated to 600-700℃ in an argon atmosphere at a heating rate of 5℃ / min.

10. A system for a water purification catalyst and its preparation process, characterized in that, It includes a precursor preparation and etching unit, a washing and stripping unit, an ion adsorption and loading unit, a vapor phase phosphating unit, a polymer coating unit, a high-temperature carbonization and post-treatment unit, and a central control and material conveying unit. The precursor preparation and etching unit includes an acidification reactor, a precision metering pump, a temperature controller, and a high-speed stirrer, used to prepare the etching solution; The washing and stripping unit includes a multi-stage centrifugal washer, an ultrasonic dispersion tank, a vacuum freeze dryer, and an online pH meter, used for washing, freezing, and drying to obtain... powder; The ion adsorption and loading unit includes a constant-temperature stirred adsorption reactor, a precision liquid feeding system, and a centrifuge, used to prepare ions adsorbed with metal cations. intermediate; The gas-phase phosphating unit includes a tubular atmosphere furnace system, a powder feeder, a temperature control system, an argon gas path and flow controller, used for preparing... @A-TMP; The polymer coating unit includes a buffer preparation and constant temperature stirred reactor, a pH meter, and a liquid feed pump, which are used to connect to a centrifuge and perform solid-liquid separation. The high-temperature carbonization and post-processing unit includes a second tubular atmosphere furnace system, a crucible or quartz boat, an inert gas protection system, and a temperature control program, used to prepare the final catalyst. @A-TMP@NC; The central control and material conveying unit includes a programmable logic controller, a distributed control system, a sensor network, pipelines, and a pump and valve system, which are used to integrate and control the operation of the entire system. The precursor preparation and etching unit and the washing and stripping unit are connected by a corrosion-resistant pump and a closed pipeline; the washing and stripping unit and the ion adsorption and loading unit are connected by a pneumatic conveying system or a closed screw feeder under inert gas protection; the ion adsorption and loading unit and the gas phase phosphating unit are connected by a vacuum conveyor belt or a closed bucket elevator; the gas phase phosphating unit and the polymer coating unit are connected by a mechanical conveying device under inert atmosphere protection; the polymer coating unit and the high-temperature carbonization and post-treatment unit are connected by a high-temperature resistant conveyor belt.

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