Platinum-tin bimetallic functional catalyst, preparation method and application of platinum-tin bimetallic functional catalyst in chlorine-containing volatile polluted organic matters

Abstract

The invention discloses a platinum-tin bimetallic functional catalyst, a preparation method and an application of the platinum-tin bimetallic functional catalyst in chlorine-containing volatile polluted organics, and the preparation method comprises the following steps: mixing an isopropanol solution of SnCl4. 5H2O or SnCl2. 2H2O with an isopropanol solution containing diethylenetriamine and titanium isopropylate, and then carrying out hydrothermal reaction and roasting to obtain a Sn-TiO2 oxide carrier; and adding the Pt solution into the water suspension of the Sn-TiO2 oxide carrier, drying by distillation, and then carrying out reduction reaction to obtain the platinum-tin bimetallic functional catalyst. According to the metal composite oxide, the Sn-TiO2 nanosphere carrier is prepared through in-situ synthesis, precious metal platinum is evenly distributed on the surface of the Sn-TiO2 nanosphere carrier, catalytic degradation of CVOCs can be effectively promoted, and the sulfur resistance of a catalyst can be effectively improved. According to the catalyst disclosed by the invention, the degradation efficiency of the chlorine-containing VOCs is remarkably improved, the treatment cost is reduced, and the negative influence on the environment is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of air pollution control, and specifically relates to a platinum-tin bimetallic functional catalyst and a preparation method thereof, and application thereof in chlorine-containing volatile polluting organic matter. Background Art

[0002] Common air pollution phenomena include acid rain, photochemical smog, ozone layer depletion and severe haze, which not only damage the natural environment, but also pose a major threat to human health. The impact of haze is particularly significant, leading to an increase in respiratory diseases. Its composition is complex, containing nearly 100 compounds that are harmful to health. In particular, fine particles with a particle size of less than 2.5μm (PM2.5) can penetrate deep into the respiratory tract and alveoli, and may cause a variety of health problems such as acute rhinitis and bronchitis. What is more worrying is that living in such an environment for a long time may also increase the risk of lung cancer, damage the cardiovascular system, and may even affect mental health and cause depression and other problems. Studies have shown that volatile organic compounds (VOCs) are an important factor in the formation of haze.

[0003] Volatile organic compounds (VOCs) are organic substances composed of a variety of high vapor pressure (>133.32Pa) and low boiling point (50~260℃) organic compounds. Its environmental sources mainly include incomplete combustion of fuels and waste incineration, organic emissions in chemical production processes (such as oil refining, petrochemicals, coatings, inks, adhesives, pesticides and medicines), and volatile emissions during the use of solvents, involving printing and packaging, automotive spraying, furniture manufacturing and other fields. The main components of VOCs include alkanes, aromatic hydrocarbons, alkenes, halogenated hydrocarbons, esters, aldehydes and ketones.

[0004] Among them, chlorinated hydrocarbons have become the focus and difficulty of research due to their environmental persistence, strong toxicity, difficulty in degradation and the generation of various harmful by-products during the treatment process. At present, the technologies for treating chlorinated volatile organic compounds (CVOCs) in industrial processes mainly include condensation, absorption, thermal combustion, biological treatment, low-temperature plasma, photocatalysis and catalytic combustion. Among them, catalytic combustion is widely used in industrial waste gas treatment due to its low energy consumption, simple operation and environmental protection characteristics.

[0005] Catalysts face complex atmospheric conditions in industrial applications. For example, in pharmaceutical plants, petrochemical industries, and sewage treatment plants, exhaust gases usually contain not only CVOCs, but also sulfur dioxide (SO2), hydrogen sulfide (H2S), and mercaptans. These chlorine- and sulfur-containing compounds compete with reactants for adsorption active sites during catalytic reactions, and may also react with the main active substances or carriers, causing irreversible chemical deactivation of the catalyst and a decrease in catalytic efficiency.

[0006] In addition, compared with other VOCs, CVOCs are more difficult to be completely oxidized, so a higher reaction temperature is required during the catalytic combustion process. However, too high a reaction temperature may promote the formation of highly toxic dioxins, and if a variety of chlorine byproducts are produced during the catalytic oxidation process, it may further promote the formation of dioxins and polychlorinated dibenzofurans. Therefore, it is particularly important to design a catalyst with excellent low-temperature redox performance so that pollutants can be completely degraded at lower temperatures, good deep oxidation ability to avoid the formation of polychlorinated byproducts, and strong anti-poisoning ability. Summary of the invention

[0007] In order to solve the technical problems of high reaction temperature, large number of by-products and easy poisoning of catalysts in the prior art when removing CVOCs, the purpose of the present invention is to provide a platinum-tin bimetallic functional catalyst and a preparation method and its application in chlorine-containing volatile polluting organic matter.

[0008] To achieve the above purpose, the technical solution adopted by the present invention is as follows: A method for preparing a platinum-tin bimetallic functional catalyst comprises the following steps: The isopropanol solution of SnCl4·5H2O or SnCl2·2H2O is mixed with the isopropanol solution containing diethylenetriamine and titanium isopropoxide to obtain a mixed solution; The mixed solution is subjected to a hydrothermal reaction to obtain a solid; calcining the solid to obtain a Sn-TiO2 oxide support; The Pt solution is added into the aqueous suspension of the Sn-TiO2 oxide carrier, and after evaporation, a reduction reaction is carried out to obtain a platinum-tin bimetallic functional catalyst.

[0009] Furthermore, the usage ratio of SnCl4·5H2O, diethylenetriamine and titanium isopropoxide is 3.5~7.0g:0.05~1mL:3.35~6.7mL, and the usage ratio of SnCl2·2H2O, diethylenetriamine and titanium isopropoxide is 3.5~7.0g:0.05~1mL:3.35~6.7mL.

[0010] Furthermore, the temperature of the hydrothermal reaction is 160-200°C and the time is 24h.

[0011] Further, the temperature is increased to 160-200°C at a heating rate of 10-20°C / min.

[0012] Furthermore, the calcination temperature is 350-450°C and the calcination time is 1.5-2.5h.

[0013] Furthermore, the Pt solution is a solution of chloroplatinic acid hexahydrate, platinum nitrate, platinum chloride or acetylacetonate platinum, and the mass ratio of one of platinum acid hexahydrate, platinum nitrate, platinum chloride and acetylacetonate platinum to the Sn-TiO2 oxide carrier is 0.01-0.03:6.

[0014] Furthermore, the reduction reaction temperature is 350-450°C and the time is 1-2h.

[0015] Furthermore, the reduction reaction is carried out in a mixed atmosphere of H2 and Ar; the temperature is increased to 350~450°C at a heating rate of 1~2°C / min.

[0016] A platinum-tin bimetallic functional catalyst.

[0017] The invention discloses an application of a platinum-tin bimetallic functional catalyst in chlorine-containing volatile polluting organic matter.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention designs a ternary metal element system, utilizing the synergistic effect between the ternary metal elements (Pt, Sn, Ti), wherein the Pt element mainly plays the role of providing low-temperature reduction active sites to promote the complete degradation of pollutants at relatively low temperatures; the Ti element is mainly used to achieve deep oxidation of target pollutants and reduce the generation of polychlorinated byproducts; the introduction of the Sn element helps to anchor and protect the Pt component, which can effectively prevent its sintering and chlorine poisoning. The ternary metal elements cooperate with each other and promote the deep oxidation of vinyl chloride at the same time. The present invention utilizes a one-step hydrothermal method to make the prepared catalyst have a larger specific surface area, which can effectively promote the transmission of target pollutants on the surface of the catalytic material. In the present invention, the precious metal platinum can be highly dispersed on the surface of the carrier, so it has excellent low-temperature reducibility and acid-base sites.

[0019] The present invention develops a platinum-based dispersed ternary metal catalyst with good low-temperature activity, chlorine resistance, and carbon deposition resistance according to the emission characteristics and molecular features of chlorinated volatile organic compounds, thereby achieving high conversion efficiency, strong anti-poisoning ability, and good anti-carbon deposition effect while achieving its environmentally friendly characteristics. In the present invention, the hydrothermal reaction and reduction reaction promote the electron transition of tin-titanium oxide, thereby freeing up oxygen vacancies around the active sites, thereby allowing the platinum element to be anchored and captured in a directional manner, and then combined with thermal reduction to promote the co-reduction between platinum and the carrier, promote the electron exchange between the elements, and realize the design and preparation of efficient catalysts. The ternary multifunctional platinum-tin bimetallic functional catalyst for the synergistic treatment of chlorinated volatile organic compounds prepared by the invention has excellent low-temperature catalytic activity of chlorinated volatile organic compounds, good selectivity, and outstanding anti-poisoning performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1It is the temperature programmed reduction (H2-TPR) curve of the platinum-tin bimetallic functional catalyst catalytic material in the present invention; Figure 2 It is the temperature programmed desorption (O2-TPD) curve of the platinum-tin bimetallic functional catalyst catalytic material in the present invention; Figure 3 The BET curve of nitrogen adsorption and desorption (BET) of the specific surface area of ​​the platinum-tin bimetallic functional catalyst material in the present invention; Figure 4 The activity test curve of the platinum-tin bimetallic functional catalyst material in the present invention for catalytic degradation of vinyl chloride; Figure 5 This is a stability test curve of the platinum-tin bimetallic functional catalyst material in the present invention catalytically degrading vinyl chloride in an atmosphere containing sulfur dioxide. DETAILED DESCRIPTION

[0021] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly and comprehensively understood.

[0022] The present invention discloses a method for preparing a platinum-tin bimetallic functional catalyst, which utilizes a one-step hydrothermal method, an ultrasonic dissolution method, a low-temperature step-by-step vacuum drying method, an excessive impregnation method, a thermal oxidation method, and a thermal reduction method to prepare a ternary multifunctional platinum-tin bimetallic functional catalytic material Pt / Sn-TiO2 for synergistically treating chlorinated volatile organic compounds. The present invention uses a one-step hydrothermal method and a thermal oxidation method to promote the electron transition of tin-titanium oxide, thereby leaving oxygen vacancies around the active sites, thereby allowing the platinum element to be directionally anchored and captured, and then combined with thermal reduction to promote the co-reduction between platinum and the carrier, thereby promoting the electron exchange between the elements and realizing the design and preparation of efficient catalysts. The ternary multifunctional platinum-tin bimetallic functional catalyst for synergistically treating chlorinated volatile organic compounds prepared by the present invention has excellent low-temperature catalytic activity for chlorinated volatile organic compounds and outstanding chlorine resistance. The specific steps are as follows: (1) Dissolve 3.5-7.0 g of SnCl4·5H2O or SnCl2·2H2O in a certain amount (1-2 mL) of isopropanol, and ultrasonicate for 5-6 min (ultrasonic frequency 40 kHz) at room temperature using an ultrasonic machine, and continuously oscillate the solution until it is completely dissolved and a clear and transparent solution A is formed; (2) Add 0.05-1 mL of diethylenetriamine dropwise into 70-150 mL of isopropanol and stir at 400-600 r / min for 5 min at room temperature until the liquids are completely mixed and a clear and transparent solution B is formed; (3) 3.35-6.7 mL of titanium isopropoxide was rapidly added to the solution B in step (2), and then stirred at 400-600 r / min for 2-5 min at room temperature until the liquids were completely mixed and a clear and transparent solution C was formed; (4) Add 0.5 mL of solution A in step (1) dropwise into solution C in step (3), with the drop rate controlled at 10-15 drops / min, to obtain a mixed solution. The mixed solution is then stirred at 400-600 r / min for 5-10 min at room temperature; the solution is then subjected to variable wave ultrasound at 20-25°C for 5-6 min (ultrasonic frequency 40 kHz), and the solution is continuously oscillated until it is completely dissolved and a clear and transparent solution D is formed; (5) Take 70 mL of solution D in step (4) and transfer it to a 100 mL stainless steel reactor lined with Teflon. Place the reactor in an oven and heat it to 160-200°C at a heating rate of 10-20°C / min and maintain it for 24 hours to obtain a solid-liquid mixture; (6) The solid-liquid mixture obtained in step (5) is centrifuged to collect solids. The centrifuge speed is 7500-8500 r / min, and the centrifugation time is 3-7 min.

[0023] (7) The obtained solid was washed with anhydrous ethanol for multiple times to obtain a light yellow powder, and then the obtained light yellow powder was placed in an oven at 60-80°C for 18-28 hours until the obtained powder was dry; the obtained sample was calcined in a muffle furnace at 350-450°C for 1.5-2.5 hours to finally obtain a Sn-TiO2 oxide carrier with a high specific surface area; (8) Take 0.6 g of Sn-TiO2 oxide carrier with high specific surface area into a 100 mL eggplant-shaped bottle, add 20 mL of deionized water, and use ultrasound to evenly disperse the carrier. Then stir at 400-600 r / min at room temperature for 2-5 min to obtain suspension E.

[0024] (9) Take 1 g of chloroplatinic acid hexahydrate, platinum nitrate, platinum chloride or platinum acetylacetonate, add 10 mL of deionized water, and stir at 400-600 r / min at room temperature for 5-10 min until the liquids are completely mixed and a slightly yellow, clear and transparent solution is formed, i.e., the Pt solution.

[0025] (10) 0.01-0.03 mL of the Pt solution obtained in step (9) was added dropwise to the suspension E in step (8), and then the eggplant-shaped bottle was placed on a rotary evaporator. Under the conditions of temperature of 50°C and rotation speed of 130 r / min, the vacuum degree was first set to -20 KPa for evaporation for 2 h, and then the vacuum degree was set to -90 KPa until the solution was evaporated to dryness to obtain a sample; (11) The sample obtained in step (10) is placed in a tube furnace, and in a mixed atmosphere of H2 and Ar (H2 volume percentage is 10-20%), the temperature is increased by 1-2°C / min to 350-450°C, and reduced for 1-2h to obtain a platinum-tin bimetallic functional catalyst with a high specific surface area, namely Pt / Sn-TiO2.

[0026] The catalytic material prepared by step (4) to step (7) and step (7) under low-temperature step-by-step vacuum drying and thermal reduction enables the precious metal platinum to be highly dispersed on the carrier surface and can be directionally anchored on the Sn species, so it has a high Pt species dispersion, excellent low-temperature reducibility and abundant acidic and basic sites.

[0027] The catalyst prepared by the present invention has a large specific surface area and can effectively promote the transmission of target pollutants on the surface of the catalytic material.

[0028] The catalyst prepared by low-temperature step-by-step vacuum drying and thermal reduction allows the precious metal platinum to be highly dispersed on the carrier surface, so it has excellent low-temperature reducibility and acid-base sites.

[0029] The catalyst prepared by the present invention contains ternary metal elements (Pt, Sn, Ti), which work together. Pt mainly provides low-temperature reduction active sites in the system, Ti element mainly realizes deep oxidation of target pollutants, and the directional anchoring of Pt element on Sn site enables Sn to limit Pt sintering and prevent Pt element from chlorine poisoning, thereby protecting the catalyst activity to be stable, and the ternary metal elements work together to promote the deep oxidation of vinyl chloride at the same time.

[0030] The catalyst of the present invention can be used in the treatment of chlorine-containing volatile polluting organic matter. The catalyst has a reaction space velocity of 40000-50000 ml·h -1 ·g -1 , under the condition of oxygen concentration of 10~21%, 90% degradation of vinyl chloride in typical industrial CVOCs can be achieved at around 270℃, and the activity will not decrease for at least 55 hours when 200ppm SO2 is introduced.

[0031] Example 1 A platinum-tin bimetallic functional catalyst material was prepared by a one-step hydrothermal method, an ultrasonic dissolution method, a low-temperature step-by-step vacuum drying method, an excessive impregnation method, a thermal oxidation method, and a thermal reduction method; Dissolve 5.25 g of SnCl4·5H2O in a certain amount (1.5 mL) of isopropanol, ultrasonicate with an ultrasonic machine at room temperature for 5 min (ultrasonic frequency 40 kHz), and continuously oscillate the solution until it is completely dissolved and a clear and transparent solution is formed to obtain a Sn solution; add 0.05 mL of diethylenetriamine dropwise into 70.5 mL of isopropanol, stir at 500 r / min at room temperature for 5 min, until the liquid is completely mixed and a clear and transparent solution is formed. Then 3.35mL of titanium isopropoxide was quickly added to the transparent solution, and then stirred at 500r / min for 5min at room temperature to fully mix the liquid; 0.5mL of Sn solution was added dropwise (the dropping speed was controlled at 15 drops / min), and then the mixed solution was stirred at 500r / min for 5min at room temperature; then the solution was ultrasonicated at 20℃ for 6min, and the solution was continuously oscillated until it was completely dissolved; the oscillated solution was placed in a reactor and heated to 200℃ at a heating rate of 20℃ / min and reacted for 24h, and then washed by centrifugation with anhydrous ethanol (the centrifuge speed was 7500r / min, and the centrifugation time was 7min). Dry in an oven at 60℃ for 24h, and after drying, the powder was placed in a muffle furnace and calcined at 400℃ for 2h. After obtaining the sample, the carrier was dispersed with excess deionized water, and then 0.03 mL of H2PtCl6·6H2O aqueous solution was added dropwise (1 g of H2PtCl6·6H2O was added to 10 mL of deionized water and stirred at 400 r / min for 7 min at room temperature). After stirring evenly, a rotary evaporator was used at a temperature of 50°C and a rotation speed of 130 r / min. The vacuum was first set to -20 KPa for evaporation for 2 h, and then the vacuum was set to -90 KPa until the solution was evaporated to dryness. Finally, the obtained sample was placed in a tubular furnace, and under a 10% H2 / Ar atmosphere, the heating rate was increased by 2°C / min to 400°C, and the sample was reduced for 1 h to obtain a Pt / Sn-TiO2 ternary metal catalyst with a high specific surface area, i.e., a platinum-tin bimetallic functional catalyst.

[0032] Activity test and evaluation of platinum-tin bimetallic functional catalyst for catalytic degradation of vinyl chloride: The solid powder obtained in Example 1 was tableted and sieved (40-60 mesh), and 0.5 g of the sieved catalytic material was accurately weighed. Vinyl chloride was used as the probe gas, the concentration of the reactant was controlled at 1000 ppm, the reaction space velocity was 42000 mL / g·h and the oxygen concentration was 15%. The catalytic reaction activity of the catalyst at different temperatures (90, 150, 200, 250, 270, 290 and 300°C) was tested, and the reaction products were monitored and analyzed by gas chromatography.

[0033] Stability test of catalytic degradation of vinyl chloride by platinum-tin bimetallic functional catalyst: The solid powder obtained in Example 1 was pressed into tablets and sieved (40-60 mesh). 0.5 g of the sieved catalytic material was accurately weighed and placed in the fixed bed of the evaluation device. Vinyl chloride was used as the probe gas. The concentration of the reactants was controlled at 1000 ppm, the SO2 concentration was 200 ppm, and the reaction space velocity was 42000 h -1 The oxygen concentration was 15%, and the catalytic reaction activity of the catalyst was continuously tested at 270 °C. The reaction products were monitored and analyzed by gas chromatography.

[0034] Analysis of intermediates in the degradation of vinyl chloride by platinum-tin bimetallic functional catalyst: The solid powder obtained in Example 1 was tableted and sieved (40-60 mesh), and 0.5 g of the sieved catalytic material was accurately weighed. Vinyl chloride was used as the probe gas, the concentration of the reactants was controlled at 1000 ppm, the reaction space velocity was 42000 mL / g·h, the oxygen concentration was 15%, and the intermediate product generation of the catalyst at different temperatures (90, 150, 200, 250, 270, 290 and 300°C) was tested respectively, and the reaction products were monitored and analyzed by gas chromatography and in-situ online mass spectrometry.

[0035] Figure 1 This is the temperature-programmed reduction (H2-TPR) curve of the platinum-tin bimetallic functional catalyst catalytic material. As can be seen from the figure, the platinum-tin bimetallic functional catalyst catalytic material has a reducible peak at 126°C, indicating that the material has excellent low-temperature reducibility and has great advantages in the field of catalytic oxidation.

[0036] Figure 2 This is the temperature-programmed oxygen desorption (O2-TPD) curve of the platinum-tin bimetallic functional catalyst material. As can be seen from the figure, the platinum-tin bimetallic functional catalyst material has oxygen desorption peaks at 310, 550, 706 and 802°C, indicating that the material contains a lot of surface physical / chemical adsorbed oxygen, surface lattice oxygen and bulk lattice oxygen, which can promote the deep oxidation of chlorine-containing volatile organic pollutants.

[0037] Figure 3 This is the nitrogen adsorption-desorption (BET) curve of the specific surface area of ​​the platinum-tin bimetallic functional catalyst material. As can be seen from the figure, the surface of the platinum-tin bimetallic functional catalyst material contains a rich mesoporous structure, which can effectively promote the mass transfer of CVOCs and effectively promote the desorption of toxic species on the material surface during the reaction.

[0038] Figure 4 This is the activity test curve of the platinum-tin bimetallic functional catalyst material for vinyl chloride. As can be seen from the figure, the platinum-tin bimetallic functional catalyst material has good low-temperature catalytic performance. It is at 270°C and the reaction space velocity is about 42000ml·h -1·g -1 Under these conditions, 90% conversion of 1,2-dichloroethane can be achieved, which can basically be applied to the current industrial catalytic RCO catalytic reaction device and can achieve good results.

[0039] Figure 5 This is the stability test curve of platinum-tin bimetallic catalyst material in the presence of sulfur. It can be seen from the figure that the platinum-tin bimetallic catalyst material has a stable reaction temperature of 270°C and a reaction space velocity of about 42000 ml·h under the condition of 200ppm SO2. -1 ·g -1 In about 55 hours, the catalytic material maintained a conversion rate of vinyl chloride above 85%. During the reaction, SO2 may interact with the reactants or the catalyst surface to generate sulfate species, which in turn promotes the formation of active sites or enhances the electronic properties of the catalyst, thereby improving the conversion rate of vinyl chloride and showing very excellent sulfur resistance and oxidation stability of chlorinated volatile organic compounds.

[0040] Example 2 Dissolve 3.5 g of SnCl4·5H2O in a certain amount (1 mL) of isopropanol, ultrasonicate with an ultrasonic machine at room temperature for 5 min (ultrasonic frequency 40 kHz), and continuously oscillate the solution until it is completely dissolved and a clear and transparent solution is formed to obtain a Sn solution; add 0.05 mL of diethylenetriamine dropwise into 70.5 mL of isopropanol, stir at 400 r / min at room temperature for 5 min, until the liquid is completely mixed and a clear and transparent solution is formed. Then 3.35mL of titanium isopropoxide was quickly added to the transparent solution, and then stirred at 400r / min for 2-5min at room temperature to fully mix the liquid; 0.5mL of Sn solution was added dropwise (the dropping speed was controlled at 12 drops / min), and then the mixed solution was stirred at 400r / min for 5min at room temperature; then the solution was ultrasonicated at 25℃ for 5min, and the solution was continuously oscillated until it was completely dissolved; the oscillated solution was placed in a reactor and heated to 160℃ at a heating rate of 10℃ / min and reacted for 24h, and then washed by centrifugation with anhydrous ethanol (centrifuge speed was 8000r / min, and the centrifugation time was 5min). Dry in an oven at 60℃ for 28h, and then put into a muffle furnace for calcination at 450℃ for 1.5h. After obtaining the sample, the carrier is dispersed with excess deionized water, and then added dropwise into 0.02 mL of platinum nitrate aqueous solution (1 g of platinum nitrate is added to 10 mL of deionized water, and stirred at 600 r / min for 5 min at room temperature). After stirring evenly, a rotary evaporator is used at a temperature of 50°C and a rotation speed of 130 r / min, first setting the vacuum degree to -20 KPa for evaporation for 2 h, and then setting the vacuum degree to -90 KPa until the solution is evaporated to dryness; finally, the obtained sample is placed in a tubular furnace, and in an H2 / Ar atmosphere with a H2 volume percentage of 10%, the heating rate is increased by 1°C / min to 350°C, and the reduction is performed for 2 h to obtain a Pt / Sn-TiO2 ternary metal catalyst with a high specific surface area, that is, a platinum-tin bimetallic functional catalyst.

[0041] Example 3 Dissolve 7.0 g of SnCl4·5H2O in a certain amount (2 mL) of isopropanol, ultrasonicate with an ultrasonic machine at room temperature for 6 min (ultrasonic frequency 40 kHz), and continuously oscillate the solution until it is completely dissolved and a clear and transparent solution is formed to obtain a Sn solution; add 0.05 mL of diethylenetriamine dropwise into 70.5 mL of isopropanol, stir at 600 r / min at room temperature for 5 min, until the liquid is completely mixed and a clear and transparent solution is formed. Then 3.35mL of titanium isopropoxide was quickly added to the transparent solution, and then stirred at 600r / min for 2-5min at room temperature to fully mix the liquid; 0.5mL of Sn solution was added dropwise (the dropping speed was controlled at 15 drops / min), and then the mixed solution was stirred at 600r / min for 8min at room temperature; then the solution was ultrasonicated at 22°C for 6min, and the solution was continuously oscillated until it was completely dissolved; the oscillated solution was placed in a reactor and heated to 180°C at a heating rate of 15°C / min and reacted for 24h, and then washed by centrifugation with anhydrous ethanol (centrifuge speed was 8500r / min, and the centrifugation time was 7min). Dry in an oven at 80°C for 18h, and then put into a muffle furnace for calcination at 380°C for 2.0h. After obtaining the sample, the carrier is dispersed with excess deionized water, and then 0.01 mL of platinum chloride aqueous solution is added dropwise (1 g of platinum chloride is added to 10 mL of deionized water, and stirred at 400 r / min for 10 min at room temperature). After stirring evenly, a rotary evaporator is used at a temperature of 50°C and a rotation speed of 130 r / min. The vacuum degree is first set to -20 KPa for evaporation for 2 h, and then the vacuum degree is set to -90 KPa until the solution is evaporated to dryness; finally, the obtained sample is placed in a tubular furnace, and under the conditions of a H2 / Ar atmosphere with a H2 volume percentage of 10%, the heating rate is increased by 2°C / min to 450°C, and the reduction is performed for 1 h to obtain a Pt / Sn-TiO2 ternary metal catalyst with a high specific surface area, that is, a platinum-tin bimetallic functional catalyst.

[0042] Example 4 Dissolve 5.0 g of SnCl4·5H2O in a certain amount (2 mL) of isopropanol, ultrasonicate with an ultrasonic machine at room temperature for 5 min (ultrasonic frequency 40 kHz), and continuously oscillate the solution until it is completely dissolved and a clear and transparent solution is formed to obtain a Sn solution; add 0.05 mL of diethylenetriamine dropwise into 70.5 mL of isopropanol, stir at 500 r / min at room temperature for 5 min, until the liquid is completely mixed and a clear and transparent solution is formed. Then 3.35mL of titanium isopropoxide was quickly added to the transparent solution, and then stirred at 500r / min for 2-5min at room temperature to fully mix the liquid; 0.5mL of Sn solution was added dropwise (the dropping speed was controlled at 10 drops / min), and then the mixed solution was stirred at 500r / min for 10min at room temperature; then the solution was ultrasonicated at 20℃ for 6min, and the solution was continuously oscillated until it was completely dissolved; the oscillated solution was placed in a reactor and heated to 190℃ at a heating rate of 18℃ / min and reacted for 24h, and then washed by centrifugation with anhydrous ethanol (centrifuge speed was 7500r / min, and the centrifugation time was 3min). Dry in an oven at 70℃ for 25h, and then put into a muffle furnace for calcination at 350℃ for 2.5h. After obtaining the sample, the carrier is dispersed with excess deionized water, and then 0.03 mL of acetylacetonate platinum aqueous solution (1 g of acetylacetonate platinum is added to 10 mL of deionized water and stirred at 400 r / min for 10 min at room temperature) is added dropwise. After stirring evenly, a rotary evaporator is used at a temperature of 50°C and a rotation speed of 130 r / min. First, the vacuum degree is set to -20 KPa for evaporation for 2 h, and then the vacuum degree is set to -90 KPa until the solution is evaporated to dryness; finally, the obtained sample is placed in a tubular furnace, and under the conditions of a H2 / Ar atmosphere with a H2 volume percentage of 10%, the heating rate is increased by 2°C / min to 380°C, and the reduction is carried out for 1.5 h to obtain a Pt / Sn-TiO2 ternary metal catalyst with a high specific surface area, that is, a platinum-tin bimetallic functional catalyst.

[0043] The present invention designs the catalyst structure and microscopic morphology, combines the properties of the elements themselves, exerts their respective functions, and then uses the catalyst prepared under specific conditions to synergistically and effectively catalyze chlorinated volatile organic pollutants (CVOCs). The metal composite oxide is prepared by in-situ synthesis of Sn-TiO2 nanosphere carriers, and the precious metal platinum is evenly distributed on the surface, which can not only effectively promote the catalytic degradation of CVOCs, but also effectively improve the sulfur resistance of the catalyst. Compared with the prior art, the material of the present invention can achieve efficient degradation at a lower temperature and reduce energy consumption; it has excellent catalytic reaction sustainability; by optimizing the composition, structure and operating conditions of the catalyst, the degradation efficiency of chlorinated VOCs is significantly improved, the processing cost is reduced, and the negative impact on the environment is reduced. This technology provides a solid foundation for the development of new catalysts and their promotion in practical applications, and has good industrial application prospects.

[0044] The above description is only for the best embodiment of the present invention, but it should not be understood as limiting the claims. The present invention is not limited to the above embodiments, and its specific structure is allowed to be changed. However, all changes made within the protection scope of the independent claims of the present invention are within the protection scope of the present invention.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

Claims

1. A method for preparing a platinum-tin bimetallic functional catalyst, characterized in that: The following steps are involved: The isopropanol solution of SnCl4·5H2O or SnCl2·2H2O is mixed with the isopropanol solution containing diethylenetriamine and titanium isopropoxide to obtain a mixed solution; The mixed solution is subjected to a hydrothermal reaction to obtain a solid; calcining the solid to obtain a Sn-TiO2 oxide support; The Pt solution is added into the aqueous suspension of the Sn-TiO2 oxide carrier, and after evaporation, a reduction reaction is carried out to obtain a platinum-tin bimetallic functional catalyst.

2. The method for preparing a platinum-tin bimetallic functional catalyst according to claim 1, characterized in that: The usage ratio of SnCl4·5H2O, diethylenetriamine and titanium isopropoxide is 3.5~7.0g:0.05~1mL:3.35~6.7mL, and the usage ratio of SnCl2·2H2O, diethylenetriamine and titanium isopropoxide is 3.5~7.0g:0.05~1mL:3.35~6.7mL.

3. The preparation method of the platinum-tin bimetallic functional catalyst according to claim 1, characterized in that: The temperature of the hydrothermal reaction is 160~200℃ and the time is 24h.

4. The method for preparing the platinum-tin bimetallic functional catalyst according to claim 3, characterized in that: The temperature was raised to 160-200°C at a heating rate of 10-20°C / min.

5. The method for preparing a platinum-tin bimetallic functional catalyst according to claim 1, characterized in that: The calcination temperature is 350~450℃ and the calcination time is 1.5~2.5h.

6. The method for preparing the platinum-tin bimetallic functional catalyst according to claim 1, characterized in that: The Pt solution is a solution of chloroplatinic acid hexahydrate, platinum nitrate, platinum chloride or platinum acetylacetonate, and the mass ratio of one of platinic acid hexahydrate, platinum nitrate, platinum chloride and platinum acetylacetonate to the Sn-TiO2 oxide carrier is 0.01-0.03:

6.

7. The method for preparing a platinum-tin bimetallic functional catalyst according to claim 1, characterized in that: The temperature of the reduction reaction is 350~450℃ and the time is 1-2h.

8. The method for preparing the platinum-tin bimetallic functional catalyst according to claim 7, characterized in that: The reduction reaction is carried out in a mixed atmosphere of H2 and Ar; the temperature is increased to 350~450°C at a heating rate of 1~2°C / min.

9. A platinum-tin bimetallic functional catalyst prepared according to the method according to any one of claims 1 to 8.

10. Use of a platinum-tin bimetallic functional catalyst prepared according to the method according to any one of claims 1 to 8 in chlorine-containing volatile polluting organic matter.

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