Pt-ZnIn2S4 catalyst modified based on high-vacuum radio frequency plasma as well as preparation method and application of Pt-ZnIn2S4 catalyst
Through high vacuum radio frequency plasma modification technology, a three-dimensional flower cluster Pt-ZnIn2S4-X catalyst with high activity and selectivity was prepared, which solved the problem of insufficient activity and selectivity of existing catalysts in wastewater treatment, and achieved more efficient wastewater degradation and hydrogen production performance.
Patent Information
- Application Number
- CN202510261850.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-06
- Publication Date
- 2025-06-06
AI Technical Summary
Existing catalysts such as P25 and pure ZnIn2S4 have problems with small specific surface area, poor activity, low selectivity and easy agglomeration of precious metals in wastewater treatment, resulting in poor performance in wastewater degradation and resource utilization.
High vacuum radio frequency plasma modification technology was used to prepare a three-dimensional flower cluster Pt-ZnIn2S4-X catalyst with high activity and selectivity. By controlling the modification process parameters such as temperature, time and atmosphere, the specific surface area of the catalyst and the uniform distribution of Pt atoms were improved.
It significantly improves the catalytic activity and selectivity of the catalyst, enhances its adsorption and degradation performance on wastewater such as rhodamine B, antibiotics and benzyl alcohol, and improves the efficiency of wastewater hydrogen.
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Figure CN120094610A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the fields of material chemistry, sewage treatment and pollution control technology, catalytic degradation technology of organic wastewater, industrial wastewater and medical wastewater, preparation and modification of catalysts in the field of environmental functional materials technology, and particularly relates to a Pt-ZnIn modified by high vacuum radio frequency plasma. 2 S 4 The invention relates to a method for preparing a catalyst and application thereof. Background Art
[0002] In recent years, water environment issues have become the second largest global problem after the energy crisis. In the process of rapid economic development, the total amount of domestic sewage and industrial wastewater has increased. Wastewater itself stores abundant energy resources. Modifying catalysts to improve the efficiency of hydrogen production from wastewater and thus solve environmental pollution and energy crises has great development prospects. Therefore, in recent years, the resource utilization of wastewater has attracted widespread attention.
[0003] At present, there are a large number of methods such as photocatalysis, electrocatalysis and biological purification for wastewater treatment. Among the many wastewater treatment technologies, photocatalysis is considered to be one of the most widely used treatment technologies for effective terminal wastewater treatment. This technology has the advantages of high treatment efficiency and no secondary pollution. It can be used to produce hydrogen according to the characteristics of wastewater, so it is widely used. In this technology, the design and preparation of efficient catalysts is one of the key technical difficulties of this treatment method. It is generally believed that efficient catalysts often require large specific surface area, low commercial cost of preparation, strong tolerance and repeatable regeneration. Based on this, in view of the shortcomings of the currently commonly used commercial P25 catalyst, such as small specific surface area, poor activity and low selectivity, it is urgent to develop a more efficient catalyst that can quickly degrade wastewater and recycle it. At present, a large number of catalysts have been prepared, among which three-dimensional flower cluster layered ternary metal sulfide indium zinc sulfide (ZnIn 2 S 4 ) has attracted great attention due to its high specific surface area, low toxicity, low price and other advantages. In addition, it can overcome the defects of traditional sulfide catalysts that are easily corroded by light, so it has been widely used. Unfortunately, ZnIn 2 S 4 The electron and hole separation efficiency is low and the migration ability is poor, which leads to the 2 S 4 The photocatalytic activity of ZnIn is low. To improve these problems, researchers have proposed many 2 S 4 Modification methods, such as morphology control, surface precious metal deposition, element doping, semiconductor composites, etc., although the above methods can effectively enhance the activity, there are still problems such as the easy agglomeration of precious metals, resulting in the catalyst activity improvement is not obvious.
[0004] In view of this, the present invention adopts high vacuum radio frequency plasma to modify Pt-ZnIn 2 S 4 Catalysts, synthesizing a series of Pt-ZnIn with high activity and selectivity 2 S 4 -X, and used triethanolamine, benzyl alcohol, rhodamine B and various antibiotics as target pollutants to evaluate the catalytic activity of the catalyst, which showed a higher performance than that of a single three-dimensional flower cluster ZnIn 2 S 4 and unmodified Pt-ZnIn 2 S 4 The catalyst exhibits more excellent catalytic activity. This preparation scheme can not only prepare a large number of three-dimensional flower clusters of Pt-ZnIn 2 S 4 -X, which will also have great promotion and applicability in industry and practical applications. Summary of the invention
[0005] The purpose of the present invention is to overcome the high cost of existing modification methods, the need to add acid or alkali and some additional chemical reagents, etc., and provide a new and large-scale preparation of three-dimensional flower cluster Pt-ZnIn 2 S 4 -X catalyst, prepared Pt-ZnIn 2 S 4 -X catalyst has good adsorption catalytic degradation performance for wastewater such as rhodamine B, antibiotics and benzyl alcohol.
[0006] To achieve the above-mentioned purpose, the present invention is realized by the following technical scheme: regulating the modification process such as modification reaction temperature, modification time, modification atmosphere, modification power, etc. to synthesize three-dimensional flower cluster Pt-ZnIn with uniform morphology and size 2 S 4 -X catalyst.
[0007] The technical solution of the present invention is as follows:
[0008] A method for modifying Pt-ZnIn based on high vacuum radio frequency plasma 2 S 4 The method for preparing the catalyst comprises the following steps:
[0009] (1) ZnIn 2 S 4 Dispersed in distilled water, ultrasonicated, and then the noble metal platinum salt solution was dropped into the uniformly dispersed ZnIn 2 S 4The aqueous solution is mixed, an organic solvent is added, and stirred; the mixed solution is allowed to stand for aging, centrifuged, washed several times with distilled water to remove the unadsorbed precious metal platinum salt, and then washed with ethanol and dried to obtain Pt-ZnIn 2 S 4 catalyst;
[0010] (2) Pt-ZnIn 2 S 4 -X catalyst preparation; Pt-ZnIn 2 S 4 The catalyst is laid flat on an alumina plate, placed in a tubular furnace containing a radio frequency plasma module, and connected to the gas path of the tubular furnace, and then the gas is evacuated, and then an air bag is connected to the air inlet to expose the catalyst to the atmosphere; then the frequency, power, voltage, reaction time, and reaction temperature parameters of the radio frequency plasma device are controlled to modify the catalyst; finally, Pt-ZnIn 2 S 4 -X, where X is different parameters such as time, temperature, atmosphere, catalyst.
[0011] In the above method, the ZnIn 2 S 4 Three-dimensional flower cluster ZnIn 2 S 4 .
[0012] The three-dimensional flower cluster ZnIn 2 S 4 The preparation method is as follows:
[0013] The zinc salt, indium salt and thiourea are weighed respectively, and dissolved in distilled water respectively to form solution A, solution B and solution C; then the solution B is added dropwise to the solution A and mixed and stirred evenly to obtain a mixed solution D; the solution C is added dropwise to the mixed solution D to obtain a mixed solution F; the mixed solution F is stirred at room temperature, then transferred to a polytetrafluoroethylene reactor, and kept in an oven for reaction, cooled naturally to room temperature, centrifuged to obtain a precipitate, washed with distilled water, then centrifuged and washed with ethanol, and vacuum dried to obtain a yellow flower cluster ZnIn 2 S 4 .
[0014] Compared with traditional conventional modification methods, plasma modification only acts on the surface of the material and does not affect the performance of the matrix. The surface of the treated material will be etched, a dense cross-linked layer will be formed, and polar groups will be introduced, which can improve the activity, selectivity and life of the catalyst and shorten the preparation time. Among them, radio frequency plasma is generated by high-frequency discharge ionization of low-pressure gas, which can reach a non-equilibrium state under high frequency and low pressure, so it is widely used in material surface treatment such as doping, etching and surface cleaning.
[0015] Radio frequency plasma equipment that uses plasma technology uses the effect of electric field to generate high-energy, high-activity particles between electrodes through discharge. These particles collide and react with the catalyst surface, creating defects or grafting some functional groups on its surface, thereby changing the chemical bonds and surface structure of the catalyst surface, achieving directional modification of the catalyst and achieving the purpose of improving catalyst performance.
[0016] In the above method, the noble metal platinum salt is chloroplatinate; and the organic solvent is ethanol or ethylene glycol.
[0017] In the above method, the zinc salt is zinc chloride tetrahydrate; the indium salt is indium chloride tetrahydrate; the total volume of the distilled water is 60 to 80 mL; the reaction temperature is 120 to 180° C.; the reaction time is 12 to 36 hours; the molar ratio of the added amounts of the zinc salt, the indium salt and the thiourea is 1 to 2:2 to 4:4 to 8, preferably 1:2:4.
[0018] In the above method, in step (1), the ultrasonic time is 0.5 to 2 hours; and the static aging time is 4 to 6 hours.
[0019] In the above method, in step (2), the Pt-ZnIn 2 S 4 The mass of the catalyst is 0.5 to 1.0 g; the gas extraction is to extract the gas to 10 -4 ~10 -5 Pa; the reaction temperature of the modification reaction is 30-500°C; the atmosphere is nitrogen, hydrogen, oxygen, ammonia or helium or carbon dioxide; the modification time is 0.5-6h; the modification power range is 50-1000W; the modification temperature range is 30-500°C.
[0020] Pt-ZnIn in the present invention 2 S 4 -X catalyst is a three-dimensional flower cluster catalyst with uniform size and Pt uniformly loaded on ZnIn 2 S 4 Surface; The specific surface area of the catalyst is 75.36 to 98.64 m 3 / g, exposing more active sites, having stronger water resistance, showing better ability to catalyze the degradation of organic wastewater and antibiotics, and also having excellent hydrogen production performance.
[0021] In the present invention, the three-dimensional nanoflower cluster Pt-ZnIn 2 S 4 The Pt atoms in the catalyst are more uniform and dispersed, which can effectively inhibit the agglomeration of Pt nanoparticles; in addition, the preparation method can perform in-situ etching on the catalyst surface to form more abundant surface sulfur vacancies, and the Pt atoms are more evenly dispersed. After etching, the catalyst has a larger average pore size, which can expose more active sites and present a more superior hydrogen production performance in the application of wastewater hydrogen production.
[0022] Furthermore, the three-dimensional flower cluster Pt-ZnIn 2 S 4 -X catalyst is used in the degradation of ethanol, antibiotics, triethanolamine and benzyl alcohol to produce hydrogen in a coordinated manner.
[0023] Compared with the prior art, the advantages of the present invention are:
[0024] 1. The modification of traditional methods usually requires the addition of acid, alkali or other chemical reagents, which will inevitably cause secondary pollution or introduce some impurities, resulting in uncontrollable factors such as uneven material modification. The radio frequency plasma modification method can produce complex physical and chemical changes on the catalyst surface within the range of tens to thousands of angstroms of thickness by controlling the physical parameters (such as power, gas composition, treatment time, etc.) during the plasma treatment process. This method retains the advantages of physical modification and has the advantages of fast, efficient and pollution-free treatment process. In addition, the plasma treatment is carried out under ultra-low atmospheric pressure conditions, which can effectively avoid the contamination and damage of impurities on the catalyst surface. Therefore, the method of radio frequency plasma modification of catalysts is an environmentally friendly catalyst modification method with the characteristics of high efficiency and pollution-free emissions that combines the advantages of physical modification and chemical modification. It is also an energy-saving technology that can effectively reduce energy consumption in the process of material modification, has good environmental protection, and realizes a safe and environmentally friendly method for efficient catalyst modification. Importantly, the catalyst modified by this method has better hydrogen production performance and degradation efficiency than the unmodified catalyst.
[0025] 2. Pt-ZnIn prepared by this method 2 S 4 -X can expose more Pt active sites, and Pt atoms can be evenly dispersed on the catalyst surface; in addition, after modification by this method, its surface becomes rougher, which is beneficial to the contact between wastewater and the catalyst surface. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 The three-dimensional flower cluster ZnIn prepared by the present invention 2 S 4 Scanning electron microscope image.
[0027] Figure 2 The three-dimensional flower cluster Pt-ZnIn prepared by the present invention 2 S 4 Scanning electron microscope image.
[0028] Figure 3 The three-dimensional flower cluster Pt-ZnIn prepared by the present invention 2 S 4 -N (N stands for nitrogen) scanning electron microscope image.
[0029] Figure 4 The XRD spectrum of the three-dimensional flower cluster catalyst prepared in the present invention.
[0030] Figure 5 The ZnIn prepared by the present invention 2 S 4 、Pt-ZnIn 2 S 4 Etching Pt-ZnIn under nitrogen conditions 2 S 4 -NThe hydrogen production effects of three catalysts in triethanolamine and ethanol. DETAILED DESCRIPTION
[0031] The present invention will be further described in detail below in conjunction with specific embodiments, but the embodiments of the present invention are not limited thereto. For process parameters not particularly noted, conventional techniques may be used.
[0032] Example 1
[0033] 1.0 mmol of zinc chloride tetrahydrate, 2.0 mmol of indium chloride tetrahydrate and 4.0 mmol of thiourea were weighed and dispersed and dissolved in 20 mL of distilled water to form 20 mL of solution A, 20 mL of solution B and 20 mL of solution C; then solution B was slowly added to solution A and mixed and stirred to obtain 40 mL of mixed solution D, the obtained mixed solution C was ultrasonicated for 30 min, then transferred to a 100 mL polytetrafluoroethylene reactor, then placed in a 140 ° C reactor for 24 h, cooled to room temperature, then centrifuged and washed with distilled water several times, and finally washed once with anhydrous ethanol, and dried at 80 ° C to obtain bright yellow ZnIn 2 S 4 Backup (ZIS). Figure 1 It can be seen that the morphology of pure ZIS is a spherical shape formed by stacking nanosheets. The corresponding XRD pattern is shown in Figure 4 As shown, the corresponding PDF card is 65-2023.
[0034] Example 2
[0035] Weigh 2 g of ZnIn from Example 1 above 2 S 4 Disperse it in 60 mL of distilled water and stir it to disperse it evenly, then add 5 mL of chloroplatinic acid solution, stir and ultrasonicate for 30 minutes, then age it for 6 hours. After aging, centrifuge it and wash it several times with distilled water, then wash it once with anhydrous ethanol, and finally dry it in an oven at 80 ° C for use to obtain dark yellow Pt-ZnIn 2 S 4 Spare (Pt-ZIS). The corresponding figure is attached Figure 2 After loading the precious metal Pt, the morphology does not change and is still a spherical shape composed of stacked nanosheets. The corresponding XRD pattern is shown in Figure 4 As shown, the corresponding PDF card is 65-2023, and the loading of Pt does not change its corresponding phase structure.
[0036] Example 3
[0037] Weigh 0.5 g of the dark yellow Pt-ZnIn in Example 2 above. 2 S 4 Evenly spread it on the alumina plate, then place it in a tube furnace connected to a radio frequency plasma device, then connect the gas line, and repeatedly pump the gas to 10 -5 The other end of the gas line is then connected to a different nitrogen gas to make Pt-ZnIn 2 S 4 The catalyst was fully exposed to a nitrogen atmosphere, and then the power was turned on. At a certain power of 100 W, the modification was carried out at room temperature for 1 h, and finally Pt-ZnIn 2 S 4 -N catalyst for standby use (Pt-ZIS-N). The corresponding figure is attached Figure 3 As can be seen from the figure, after RF plasma modification, the overall morphology has not changed accordingly, but its local nanosheets have become uneven, which may be caused by the etching of its surface. The corresponding XRD pattern is shown in Figure 4 As shown, after RF plasma modification, the phase structure of the corresponding catalyst has not changed, and the corresponding PDF card is 65-2023.
[0038] Example 4
[0039] Specific steps: Weigh 10 mg of the samples in Examples 1, 2 and 3 and place them in a 10 vol% ethanol aqueous solution and a 20 vol% triethanolamine aqueous solution, and connect the device. Pump the gas repeatedly to remove the interference of oxygen in the wastewater, then turn on the light to react. The change in hydrogen concentration during the reaction is finally detected online by Foley gas chromatography (9790II) GC. The hydrogen production rate is used to calculate the hydrogen production. The results show that the modified Pt-ZnIn 2 S 4 -N catalyst compared with the unmodified Pt-ZnIn 2 S 4 and single ZnIn 2 S 4 The catalyst exhibits a more superior performance in producing hydrogen from wastewater. Figure 5 .
[0040] The above embodiments are only used to illustrate the technical solutions of the present invention rather than strict conditional limitations. Those skilled in the art should understand that various changes may be made to the details or forms thereof without departing from the spirit and scope of the present invention as defined in the claims.
Claims
1. A method for preparing a Pt-ZnIn2S4 catalyst modified by high vacuum radio frequency plasma, characterized in that: The steps include: (1) dispersing ZnIn2S4 in distilled water, ultrasonicating, obtaining a uniformly dispersed ZnIn2S4 aqueous solution, then dropping a noble metal platinum salt solution into the uniformly dispersed ZnIn2S4 aqueous solution for mixing, adding an organic solvent, and stirring; allowing the mixed solution to stand for aging, centrifuging, washing, and drying to obtain a Pt-ZnIn2S4 catalyst; (2) Preparation of Pt-ZnIn2S4-X catalyst: Pt-ZnIn2S4 catalyst was laid flat on an alumina plate, placed in a tubular furnace containing a radio frequency plasma module, and the tubular furnace gas line was connected and evacuated, and then an air bag was connected to the air inlet to expose the catalyst to the atmosphere; Then, the frequency, power, voltage, reaction time and reaction temperature parameters of the radio frequency plasma device are controlled to modify the reaction; finally, Pt-ZnIn2S4-X is prepared.
2. A method for preparing a Pt-ZnIn2S4 catalyst based on high vacuum radio frequency plasma modification according to claim 1, characterized in that: The ZnIn2S4 is a three-dimensional flower cluster ZnIn2S4; The preparation method of the three-dimensional flower cluster ZnIn2S4 is as follows: Weigh zinc salt, indium salt and thiourea respectively, and dissolve them in distilled water to form solution A, solution B and solution C; Then, solution B is added dropwise to solution A and mixed and stirred to obtain a mixed solution D; Add solution C dropwise to mixed solution D to obtain mixed solution F; stir mixed solution F at room temperature, then transfer to a polytetrafluoroethylene reactor, keep warm for reaction, cool naturally to room temperature, centrifuge the product to obtain a precipitate, wash the precipitate, and vacuum dry to obtain a yellow color; cool naturally to room temperature, centrifuge the product to obtain a precipitate, wash the precipitate, and vacuum dry to obtain a yellow flower cluster of ZnIn2S4.
3. The method for preparing a Pt-ZnIn2S4 catalyst modified by high vacuum radio frequency plasma according to claim 1, characterized in that: The noble metal platinum salt is chloroplatinate; and the organic solvent is ethanol or ethylene glycol.
4. A method for preparing a Pt-ZnIn2S4 catalyst modified by high vacuum radio frequency plasma according to claim 2, characterized in that: The zinc salt is zinc chloride tetrahydrate; the indium salt is indium chloride tetrahydrate; the total volume of the distilled water is 60-80 mL; the reaction temperature is 120-180° C.; the reaction time is 12-36 h; and the molar ratio of the zinc salt, indium salt and thiourea added is 1-2:2-4:4-8.
5. The method for preparing a Pt-ZnIn2S4 catalyst modified by high vacuum radio frequency plasma according to claim 1, characterized in that: In step (1), the ultrasonic time is 0.5 to 2 hours; and the static aging time is 4 to 6 hours.
6. The method for preparing a Pt-ZnIn2S4 catalyst modified by high vacuum radio frequency plasma according to claim 1, characterized in that: In step (2), the mass of the Pt-ZnIn2S4 catalyst is 0.5 to 1.0 g; the gas extraction is performed to 10 -4 ~10 -5 Pa; the reaction temperature of the modification reaction is 30-500°C; the atmosphere is nitrogen, hydrogen, oxygen, ammonia or helium or carbon dioxide; the modification time is 0.5-6h; the modification power range is 50-1000W; the modification temperature range is 30-500°C.
7. A Pt-ZnIn2S4-X catalyst modified by high vacuum radio frequency plasma is prepared by the preparation method described in any one of claims 1 to 6.
8. The Pt-ZnIn2S4 catalyst modified by high vacuum radio frequency plasma according to claim 7, characterized in that: The Pt-ZnIn2S4-X catalyst is in the shape of a three-dimensional flower cluster with uniform size, and Pt is evenly anchored on the surface of ZnIn2S4; the average pore size of the catalyst is 75.36-98.64 m 3 / g, exposing more active sites, showing a better ability to catalyze the degradation of organic wastewater and antibiotics, and also has excellent hydrogen production performance.
9. The three-dimensional flower cluster Pt-ZnIn2S4-X catalyst described in claim 7 is used for degradation of organic wastewater and production of hydrogen.
10. The use according to claim 9, characterized in that: The organic matter in the organic wastewater includes ethanol, antibiotics, triethanolamine or benzyl alcohol.