A Pt for efficient catalytic degradation of VOCs q / Sn q -Fe2O3 catalysts, their preparation methods and applications

Abstract

The application discloses a Pt / Sn / Fe2O3 catalyst for efficiently catalyzing degradation of VOCs q / Sn q A Fe2O3 catalyst, a preparation method and application thereof are disclosed.The Sn-doped and defect-induced Sn-Fe2O3 is formed by one-time quenching with Fe2O3 as a carrier q ‑Fe2O3;Sn q ‑Fe2O3 as a carrier, and Pt clusters are loaded on the Sn-Fe2O3 by a two-time quenching method to form Pt / Sn / Fe2O3 q / Sn q ‑Fe2O3。Compared with traditional solvothermal methods, the preparation method is simple and has high repeatability.The surface electronic structure of the carrier Fe2O3 can be adjusted by quenching and Sn doping, and the surface physical and chemical properties of the carrier are optimized;active centers Pt are introduced by quenching loading, and the interaction between the optimized carrier and platinum clusters can adjust the coordination and electronic structure of the platinum clusters, so that the obtained catalyst has excellent catalytic degradation capacity for toluene / ketone.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a Pt catalyst for the degradation of volatile organic pollutants in ambient air. q / Sn q -Fe2O3 catalysts, their preparation methods, and applications. Background Technology

[0002] Volatile organic compounds (VOCs) not only harm human health and pollute the atmospheric environment, but also combine with other primary pollutants in the air, such as NO. x SO x VOCs react with ammonia and other substances to form secondary aerosols and photochemical smog. Therefore, effectively reducing the concentration of VOCs in the air is crucial. Catalytic oxidation technology, as one of the most effective methods for degrading VOCs, is mainly used to eliminate medium- and high-concentration VOCs. The presence of a catalyst can significantly reduce the activation energy of the reaction between VOC molecules and oxygen molecules, changing the reaction pathway and thus reducing energy consumption. The core issue of thermocatalytic oxidation technology is the development and preparation of cost-effective and efficient catalysts. Currently, catalysts can be mainly divided into transition metal-based catalysts and noble metal-based catalysts.

[0003] Platinum-based metals have attracted widespread attention in the field of catalytic oxidation due to their unique electronic structure and excellent intrinsic activity. However, their high cost makes balancing the catalytic activity and cost of platinum-based materials a major challenge. To achieve efficient VOCs catalytic degradation with lower platinum loadings, adjusting the coordination and electronic structure of platinum atoms at the active center is a mainstream modification method. In platinum-based catalysts, metal-support interactions form between platinum atoms and the metal oxide support, and the activity of platinum atoms can be improved through electron transfer and changes in coordination structure. Therefore, by adjusting the physicochemical properties of the oxide support, the electronic structure of the active center of the supported noble metal can be improved to some extent, giving it excellent catalytic oxidation capabilities. Transition metal oxides, such as Fe₂O₃, are a primary support due to their chemical stability, environmental friendliness, and relatively high reserves. However, for catalytic oxidation reactions, the perfectly defect-free and highly stable Fe₂O₃ lacks lattice oxygen activity and reactant adsorption sites. To enhance the ability of the support surface to activate oxygen and reactants, researchers often modify metal oxide supports through defect engineering. There are various ways to introduce defects into metal oxides, mainly including chemical reduction and plasma treatment.

[0004] In 2021, Jianmei Lu et al. published a study titled "Flower-like Pt / Fe2O3-CeO2 Catalysts for Highly Efficient Low Temperature Catalytic Oxidation of Toluene" in *Ind. Eng. Chem. Res.*. This study modified a metal oxide support using a complex solvothermal synthesis method to prepare a Fe3Ce1 oxide support, and then introduced platinum materials using a conventional impregnation method to prepare a Pt / Fe3Ce1 catalyst. The activity of the catalyst was evaluated at a toluene concentration of 50 ppm and a space velocity of 36000 mL / (h·g). However, the complex solvothermal synthesis process limits the catalyst synthesis time and yield. Moreover, the complex operating conditions, including relatively high concentrations of VOCs and the coexistence of multiple VOCs, are the primary practical considerations. Therefore, there is an urgent need to develop a new technology for the rapid synthesis of a highly efficient catalyst at a relatively high space velocity of 72000 mL / (h·g) under conditions of high concentrations (1000 ppm) of toluene and acetone coexistence. Summary of the Invention

[0005] This invention aims to improve the catalytic oxidation activity of catalysts for VOCs under relatively low platinum loading, and proposes a Pt... q / Sn q The Fe2O3 catalyst for efficient catalytic degradation of VOCs, its preparation method, and its application are described. The catalyst exhibits a simple preparation process, high catalytic activity, and stability. The catalyst prepared in this invention demonstrates excellent toluene / acetone catalytic degradation capability, achieving catalytic degradation at a space velocity of 72000 mL / (h·g) under conditions of high concentration (1000 ppm) coexistence of toluene and acetone.

[0006] To improve the physicochemical properties of the supported oxide and induce heteroatom doping and defect generation on the metal oxide surface, this invention introduces quenching technology into the catalyst preparation process. Quenching is a novel method for inducing a large number of defects on the catalyst surface. It involves instantaneously pouring a metal oxide, whose atoms are in random thermal motion at a high temperature, into a low-temperature salt solution, thereby simultaneously introducing defects and heteroatoms onto the metal oxide surface. This invention uses quenching to modify and pretreat the Fe2O3 support, increasing the defect concentration and altering the local electronic structure of the support to optimize the coordination structure of the active Pt atoms, thus achieving high catalytic performance even with low Pt loading.

[0007] The objective of this invention is achieved by at least one of the following technical solutions.

[0008] This invention provides a Pt for efficient catalytic degradation of VOCs.q / Sn q Preparation method of Fe2O3 catalyst, Pt q / Sn q In Fe2O3, 'q' indicates that the preparation method employs a quenching strategy. Quenching refers to the process of instantaneously introducing a material at a high temperature into a low-temperature / room-temperature solution. The preparation method includes the following steps:

[0009] (1) Dissolve soluble tin tetrachloride in water, stir until homogeneous to obtain tin tetrachloride solution, and store in a refrigerator for later use;

[0010] (2) Fe(OH)3 nanoparticles were placed in a muffle furnace for calcination at a temperature of 550℃~750℃ for 5h~7h. The Fe(OH)3 nanoparticles placed in the muffle furnace at 550℃~750℃ were then removed and immediately poured into a pre-prepared tin tetrachloride solution for quenching. After stirring, filtration and drying, Sn was obtained. q -Fe2O3 nanoparticles;

[0011] (3) Dissolve soluble platinum nitrate in dilute hydrochloric acid, mix and stir until homogeneous to obtain platinum nitrate solution;

[0012] (4) The obtained Sn q Fe2O3 nanoparticles were placed in a muffle furnace and calcined at 350℃~550℃ for 30min~60min; immediately afterward, Sn, which was at 350℃~550℃, was... q Fe₂O₃ nanoparticles were extracted, poured into a prepared platinum nitrate solution, quenched, and then obtained by stirring, filtration, and drying to obtain Pt. q / Sn q -Fe2O3 nanoparticles.

[0013] Further, the concentration of the tin tetrachloride solution in step (1) is 0.2 mol / L to 0.8 mol / L. Preferably, the concentration of the tin tetrachloride solution in step (1) is 0.5 mol / L.

[0014] Furthermore, the Fe(OH)3 nanoparticles described in step (2) have a particle size of 30–120 nm.

[0015] Preferably, the roasting temperature in step (2) is 600°C and the roasting time is 5 hours.

[0016] Further, the concentration of the platinum nitrate solution in step (3) is 0.3g. Pt / L~1.0g Pt / L. Preferably, the concentration of the platinum nitrate solution in step (3) is 0.7g. Pt / L.

[0017] Further, the mass percentage concentration of Pt in the Pt / Sn-Fe2O3 nanoparticles in step (4) is 0.1% to 0.9%. Preferably, the Pt in step (4) q / Sn q The mass percentage concentration of Pt in Fe2O3 nanoparticles is 0.4%.

[0018] Preferably, the roasting temperature in step (4) is 400°C and the roasting time is 40 min.

[0019] Furthermore, the stirring time in steps (2) and (4) is 3 min to 5 min.

[0020] Furthermore, the drying temperature in steps (2) and (4) is 60℃~90℃, and the drying time is 8h~12h.

[0021] Preferably, the drying temperature in steps (2) and (4) is 70°C and the drying time is 12 hours.

[0022] This invention provides a Pt catalyst prepared by the above-described method for the efficient catalytic degradation of VOCs. q / Sn q -Fe2O3 catalyst.

[0023] The present invention provides Pt for efficient catalytic degradation of VOCs q / Sn q - Application of Fe2O3 catalyst in the removal of volatile organic pollutants from ambient air.

[0024] Furthermore, the volatile organic pollutant is one or more of toluene and acetone.

[0025] This invention employs a two-stage quenching modification of the Fe2O3 metal oxide support. First, a first quenching introduces Sn ion doping and defects into the support surface to optimize the near-surface chemical properties of Fe2O3. Then, a second quenching load of low-load, highly active platinum clusters is applied, solving the technical problems of complex catalyst synthesis, poor oxygen activation ability of Fe2O3 oxide, and poor catalytic oxidation of VOCs by Pt species. Under low platinum loading, Pt... q / Sn q -Fe2O3 possesses excellent ability to activate oxygen and various VOCs, thus achieving excellent catalytic degradation of various VOCs.

[0026] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0027] This invention prepares defect-rich Pt through a two-quenching method. q / Snq The Fe2O3 catalyst has a simple and highly reproducible preparation method. A first quenching method introduces tetravalent tin atoms and defects into the Fe2O3 support, modifying the geometry and electronic structure of the Fe2O3 itself. A second quenching method then further modifies the Sn... q Pt species were loaded onto the Fe₂O₃ surface. The geometric and electronic structure of the Pt species on the support surface was significantly modulated through the interaction between the support and the metal. The resulting Pt... q / Sn q -Fe2O3 catalysts exhibit highly efficient catalytic degradation capabilities for VOCs. In the embodiments of this application, Pt... q / Sn q -Fe2O3 catalyst was used to remove VOCs (toluene, acetone, and a mixture of toluene and acetone) when the initial toluene concentration was 1000 ppm and the mass hourly space velocity (WHSV) was 72000 mL g. -1 h -1 With a Pt loading of 0.4%, the toluene degradation rate reached over 90% at 210℃; and with an initial acetone concentration of 1000 ppm and a mass hourly space velocity (WHSV) of 72000 mL g / cm³, the degradation rate was also achieved. -1 h -1 At a temperature of 230℃, the degradation rate of acetone reaches over 90%; when the initial concentration of toluene is 700 ppm, the initial concentration of acetone is 300 ppm, and the mass hourly space velocity is 72000 mL g. -1 h -1 When the temperature reaches 210℃, the total VOCs degradation rate reaches over 90%. Attached Figure Description

[0028] Figure 1 The images show the XRD patterns of the catalysts prepared in Example 1, Comparative Example 1, and Comparative Example 2.

[0029] Figure 2 The Pt prepared in Example 1 q / Sn q SEM image of the Fe2O3 catalyst.

[0030] Figure 3 The Pt prepared in Example 1 q / Sn q TEM image of the Fe2O3 catalyst.

[0031] Figure 4 The images show the toluene catalytic degradation effects of the catalysts prepared in Examples 1-5 and Comparative Example 1.

[0032] Figure 5 The images show the toluene catalytic degradation effect of the catalysts prepared in Example 1 and Comparative Examples 2-4.

[0033] Figure 6 The graphs show the toluene catalytic degradation effect of the catalysts prepared in Examples 1 and 6-9.

[0034] Figure 7 The diagram shows the acetone catalytic degradation activity of the catalysts prepared in Example 1 and Comparative Examples 1-2.

[0035] Figure 8 The diagram shows the catalytic degradation activity of the catalysts prepared in Example 1 and Comparative Examples 1-2 for a mixed gas of toluene and acetone. Detailed Implementation

[0036] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0037] Example 1

[0038] A 0.5 mol / L tin tetrachloride solution was prepared by dissolving soluble tin tetrachloride powder in water and stirring until homogeneous. Fe(OH)₃ nanoparticles were calcined in a muffle furnace at 600℃ for 5 hours. The calcined Fe(OH)₃ nanoparticles were then poured into the pre-prepared tin tetrachloride solution for quenching. After stirring, filtration, and drying, Sn was obtained. 0.5q -Fe2O3 nanoparticles (the subscript q indicates a quenching strategy, and the numbers represent the corresponding salt concentrations; other examples follow this convention); soluble platinum nitrate salt is dissolved in water, and after mixing and stirring evenly, a platinum nitrate solution with a concentration of 0.7g is obtained. Pt / L, the obtained Sn 0.5q Fe2O3 nanoparticles were placed in a muffle furnace and calcined at 400℃ for 40 minutes; the Sn particles during calcination were then... 0.5q Fe₂O₃ nanoparticles were poured into a prepared platinum nitrate solution and quenched. After stirring, filtration, and drying, Pt was obtained. 0.7q / Sn 0.5q -Fe2O3 nanoparticles.

[0039] Comparative Example 1

[0040] Fe(OH)3 nanoparticles were calcined in a muffle furnace at 600℃ for 5 hours; after natural cooling, Fe2O3 nanoparticles were obtained. A platinum nitrate solution with a concentration of 0.7 g was obtained by dissolving a soluble platinum nitrate salt in water and stirring until homogeneous. Pt / L; The prepared Fe2O3 nanoparticles were calcined in a muffle furnace at 400℃ for 40 min; The Fe2O3 nanoparticles at 400℃ were then poured into a prepared platinum nitrate solution for quenching, followed by stirring, filtration, and drying to obtain Pt. 0.7q / Fe2O3 nanoparticles.

[0041] Comparative Example 2

[0042] A 0.5 mol / L tin tetrachloride solution was prepared by dissolving soluble tin tetrachloride powder in water and stirring until homogeneous. Fe(OH)₃ nanoparticles were then calcined in a muffle furnace at 600℃ for 5 hours. After natural cooling, Fe₂O₃ powder was obtained. This powder was then immersed in the pre-prepared tin tetrachloride solution, and after stirring, filtration, and drying, Sn was obtained. 0.5s -Fe2O3 nanoparticles (the subscript 's' indicates that the preparation method is ordinary impregnation, which involves pouring room-temperature oxides into a salt solution for surface modification); soluble platinum nitrate salt is dissolved in water, and after mixing and stirring evenly, a platinum nitrate solution with a concentration of 0.7g is obtained. Pt / L; the obtained Sn 0.5s Fe2O3 nanoparticles were calcined in a muffle furnace at 400℃ for 40 minutes; Sn at 400℃ was then... s Fe₂O₃ nanoparticles were poured into a prepared platinum nitrate solution and quenched. After stirring, filtration, and drying, Pt was obtained. 0.7q / Sn 0.5s -Fe2O3 nanoparticles (the subscript q indicates that the preparation method is quenching, the subscript s indicates that the preparation method is ordinary impregnation, and the corresponding numbers before q and s indicate the concentration of the quenching solution; other embodiments are also subject to this specification).

[0043] Comparative Example 3

[0044] The only difference from Example 1 is that Sn, which was naturally cooled to room temperature, was used instead. q Fe₂O₃ nanoparticles were impregnated in a prepared platinum nitrate solution using a simple method, followed by stirring, filtration, and drying to obtain Pt. 0.7s / Sn 0.5q -Fe2O3 nanoparticles.

[0045] Comparative Example 4

[0046] The only difference from Comparative Example 2 is that Sn was naturally cooled to room temperature. s Fe₂O₃ nanoparticles were impregnated in a prepared platinum nitrate solution using a simple method, followed by stirring, filtration, and drying to obtain Pt. 0.7s / Sn 0.5s -Fe2O3 nanoparticles.

[0047] Example 2

[0048] The only difference from Example 1 is that the concentration of the tin tetrachloride solution is 0.25 mol / L; the other processes are the same as in Example 1 and will not be repeated here. The catalyst prepared in this example is labeled as Pt. 0.7q / Sn 0.25q -Fe2O3.

[0049] Example 3

[0050] The only difference from Example 1 is that the concentration of the tin tetrachloride solution is 0.8 mol / L; the other processes are the same as in Example 1 and will not be repeated here. The catalyst prepared in this example is labeled as Pt. 0.7q / Sn 0.8q -Fe2O3.

[0051] Example 4

[0052] The only difference from Example 1 is that the Fe(OH)3 nanoparticles were calcined in a muffle furnace at 500°C for 5 hours. All other processes were the same as in Example 1 and will not be repeated here. The catalyst prepared in this example is labeled Pt. 0.7q / Sn 0.5q,500℃ -Fe2O3 (where 500℃ refers to the temperature at which the material is quenched in the Sn solution; other embodiments follow this specification as well. If not specified, it is assumed to be 600℃).

[0053] Example 5

[0054] The only difference from Example 1 is that the Fe(OH)3 nanoparticles were calcined in a muffle furnace at 700°C for 5 hours. All other processes were the same as in Example 1 and will not be repeated here. The catalyst prepared in this example is labeled Pt. 0.7q / Sn 0.5q,700℃ -Fe2O3.

[0055] Example 6

[0056] The only difference from Example 1 is that the concentration of the platinum nitrate solution is 0.3g. Pt / L, other processes are the same as in Example 1, and will not be repeated here. The catalyst prepared in this example is labeled as Pt. 0.3q / Sn 0.5q -Fe2O3.

[0057] Example 7

[0058] The only difference from Example 1 is that the concentration of the platinum nitrate solution is 1.0g. Pt / L, other processes are the same as in Example 1, and will not be repeated here. The catalyst prepared in this example is labeled as Pt.1.0q / Sn 0.5q -Fe2O3.

[0059] Example 8

[0060] The only difference from Example 1 is that the Sn obtained is... 0.5q Fe₂O₃ nanoparticles were calcined in a muffle furnace at 300°C for 40 minutes. Other processes were the same as in Example 1 and will not be repeated here. The catalyst prepared in this example is labeled as Pt. 0.7q,300℃ / Sn 0.5q -Fe2O3 (where 300℃ refers to the temperature at which the material is quenched in the Pt solution; other embodiments follow this specification as well. If not specified, it is assumed to be 400℃).

[0061] Example 9

[0062] The only difference from Example 1 is that the Sn obtained is... 0.5q The Fe₂O₃ nanoparticles were calcined in a muffle furnace at 500°C for 40 minutes. Other processes were the same as in Example 1 and will not be repeated here. The catalyst prepared in this example is labeled as Pt. 0.7q,500℃ / Sn 0.5q -Fe2O3.

[0063] Performance testing

[0064] The XRD patterns of the catalysts prepared in Example 1, Comparative Example 1, and Comparative Example 2 are as follows: Figure 1 As shown, from Figure 1 It can be seen that neither the initial quenching of Sn atoms nor the secondary quenching of Pt atoms changed the phase structure of the Fe2O3 support, and no new phase peaks were generated, indicating that Sn and Pt atoms are uniformly dispersed on the surface of the Fe2O3 support. The catalyst Pt prepared in Example 1... 0.7q / Sn 0.5q SEM image of Fe2O3 as follows Figure 2 As shown, the particle size of the support particles is approximately 50 nm, and no significant changes caused by quenching were observed on the surface. The catalyst Pt prepared in Example 1... 0.7q / Sn 0.5q TEM image of Fe2O3 as shown Figure 3 As shown, the Pt species under quenching load are uniformly dispersed on the support Sn. 0.5q -The surface of the Fe2O3 material has defects at the edges.

[0065] Catalytic oxidation experiments of toluene were conducted using the catalysts prepared in Examples 1-5, Comparative Examples 1 and 2. The reaction conditions were: toluene concentration of 1000 ppm, equilibrium gas of air, and mass hourly space velocity of 72000 mL g.-1 h -1 The catalytic oxidation activities of each catalyst for toluene are as follows: Figure 4 As shown. The temperature T typically required to achieve a 90% VOCs conversion rate is used. 90 Characterizing the activity of the catalyst. Pt 0.7q / Fe2O3 has the worst activity, T 90 It is 235℃. (Compared to Pt) 0.7q Compared to Fe2O3, quenching-induced Sn doping can improve the catalytic oxidation activity of toluene to varying degrees, with the optimal Sn doping amount being 0.5%. Compared to Pt... 0.7q / Sn 0.25q -Fe2O3(T 90 =225℃) and Pt 0.7q / Sn 0.8q -Fe2O3(T 90 =225℃), Pt 0.7q / Sn 0.5q -Fe2O3 has the lowest T 90 =215℃. Meanwhile, Pt was obtained by quenching Sn solutions with Fe2O3 at different temperatures of 500℃ and 700℃. 0.7q / Sn 0.5q,700℃ -Fe2O3 and Pt 0.7q / Sn 0.5q,500℃ Pt obtained by quenching Fe2O3 catalyst at 600℃ 0.7q / Sn 0.5q -Fe2O3 still exhibits the best activity (T 90 =215℃), and Pt 0.7q / Sn 0.5q,700℃ -Fe2O3 activity (T 90 =218℃) is close to, and both are superior to Pt 0.7q / Sn 0.5q,500℃ -Fe2O3(T 90 =228℃). This indicates that the optimal temperature for quenching Sn in this invention is 600℃.

[0066] Catalytic oxidation experiments of toluene were conducted using the catalysts prepared in Examples 1 and 2-4. The reaction conditions were: toluene concentration of 1000 ppm, equilibrium gas of air, and mass hourly space velocity of 72000 mL g. -1 h -1 The catalytic oxidation activities of each catalyst for toluene are as follows: Figure 5 As shown. First, under the same Pt ​​and Sn doping amounts, compared to Pt prepared by the conventional impregnation method, Pt... 0.7s / Sn 0.5q -Fe2O3(T 90=232℃), Pt is obtained by introducing Pt through quenching. 0.7q / Sn 0.5q -Fe2O3 possesses the best toluene degradation ability (T 90 =215℃). Meanwhile, Pt prepared by introducing Sn via impregnation method. 0.7q / Sn 0.5s -Fe2O3, T 90 =225℃, its activity is lower than Pt 0.7q / Sn 0.5q -Fe2O3. Pt prepared by a two-step impregnation method. 0.7s / Sn 0.5s -Fe2O3, with the worst activity, T 90 =237℃. In summary, the overall order of activity from strongest to weakest is Pt. 0.7q / Sn 0.5q -Fe2O3>Pt 0.7q / Sn 0.5s -Fe2O3>Pt 0.7s / Sn 0.5q -Fe2O3>Pt 0.7s / Sn 0.5s -Fe2O3. This indicates that the catalyst prepared by the two-step quenching process possesses the highest activity. The main reason is that quenching with the Sn salt solution enriches the Fe2O3 surface with defects and introduces Sn ion doping, thereby improving the chemical properties of Fe2O3 and enhancing its ability to activate oxygen. The secondary quenching in Sn... q Platinum clusters loaded on the Fe2O3 surface improve the coordination and electronic structure of Pt through the interaction between the metal Pt and the support, due to the improved surface chemical properties of the oxide support.

[0067] Catalytic oxidation experiments of toluene were conducted using the catalysts prepared in Examples 1 and 6-9. The reaction conditions were: toluene concentration of 1000 ppm, equilibrium gas of air, and mass hourly space velocity of 72000 mL g. -1 h -1 The catalytic oxidation activities of each catalyst for toluene are as follows: Figure 6 As shown. In samples prepared by quenching platinum nitrate solutions of different concentrations, Pt 0.7q / Sn 0.5q -Fe2O3 has the highest activity (T) 90 =215℃), Pt 1.0q / Sn 0.5q -Fe2O3 activity is second (T) 90 =225℃), Pt 0.3q / Sn 0.5q -Fe2O3 activity is again (T) 90 =228℃). This indicates that the optimal concentration of platinum nitrate is 0.7g.Pt / L. The temperature of the support during quenching also has a significant impact on catalytic activity, Pt 0.7q / Sn 0.5q -Fe2O3 and Pt 0.7q,500℃ / Sn 0.5q -Fe2O3 has a similar activity to, but a higher activity than, Pt. 0.7q,300℃ / Sn 0.5q -Fe2O3(T 90 =237℃). This indicates that if the temperature during catalyst quenching is too low, the thermal vibration of the carrier will be insufficient, resulting in inadequate quenching strength. The performance is similar when quenched at 400℃ and 500℃, indicating that there is a certain temperature threshold; further increasing the temperature will not significantly improve performance but will instead increase costs. This suggests that the optimal quenching temperature for pt in this invention is 400℃.

[0068] The catalysts prepared in Example 1, Comparative Example 1, and Comparative Example 2 were used to study the acetone degradation activity. The reaction conditions were: acetone concentration of 1000 ppm, equilibrium gas of air, and mass hourly space velocity of 72000 mL g. -1 h -1 The catalytic oxidation activity of the catalyst for acetone is as follows: Figure 7 As shown. Specifically, Pt 0.7q / Fe2O3 has the lowest acetone oxidation activity, T 90 The temperature is 253℃. With the introduction of Sn ions, Pt... 0.7q / Sn 0.5s -Fe2O3 has a certain degree of improved acetone oxidation activity, T 90 It is 240℃, which is higher than that of Pt. 0.7q / Fe2O3 lowered the temperature by 13℃. More importantly, under the action of double quenching and the Sn accelerator, Pt 0.7q / Sn 0.5q -Fe2O3 possesses the highest acetone oxidation activity, and its T 90 It is 228℃, which is higher than that of Pt. 0.7q / Fe2O3 decreased by 25℃. This indicates that, consistent with the degradation trend of toluene, Pt 0.7q / Sn 0.5q -Fe2O3 exhibits optimal acetone degradation capability, mainly due to the presence of Sn and defects that improve the physicochemical properties of the support, and the introduction of Sn modulates the electronic structure of the active center Pt atom.

[0069] Catalysts prepared in Example 1, Comparative Example 1, and Comparative Example 2 were used to conduct catalytic degradation experiments on toluene and acetone simultaneously. To simulate the complex environment of actual operating conditions, the catalytic degradation activity of the catalysts on VOCs was also investigated in the presence of a mixed VOCs gas of toluene and acetone. Reaction conditions: toluene concentration 700 ppm, acetone concentration 300 ppm, total VOCs concentration 1000 ppm, equilibrium gas was air, and mass hourly space velocity (WHSV) was 72000 mL g. -1 h -1 The total VOCs catalytic oxidation activity of the catalyst is as follows Figure 8 As shown. Pt 0.7q The mixed VOCs with Fe2O3 have the lowest oxidation activity, T 90 The temperature is 228℃. (Pt) 0.7q / Sn 0.5s -Fe2O3 showed improved catalytic oxidation activity of VOCs, T 90 The temperature was 216℃. Under the combined effects of two quenching processes and Sn ions, Pt... 0.7q / Sn 0.5q -Fe2O3 possesses the highest catalytic oxidation capacity for mixed VOCs, and its T 90 It is 209℃, which is higher than that of Pt. 0.7q / Fe2O3 decreased by 19℃. Overall, the degradation activity trend of mixed VOCs is consistent with the degradation trends of toluene and acetone separately, and Pt 0.7q / Sn 0.5q -Fe2O3 has the best total VOCs degradation capacity.

[0070] The above embodiments are merely preferred embodiments of the present invention and are only used to explain the present invention, not to limit the present invention. Any changes, substitutions, modifications, etc., made by those skilled in the art without departing from the spirit and essence of the present invention should be within the protection scope of the present invention.

Claims

1. A Pt catalyst for efficient catalytic degradation of VOCs q / Sn q Preparation method of Fe2O3 catalyst, Pt q / Sn q In Fe2O3, 'q' indicates that the preparation method employs a quenching strategy. Quenching refers to the process of instantaneously introducing a material at a high temperature into a low-temperature / room-temperature solution. Its characteristic is... The preparation method includes the following steps: (1) Dissolve soluble tin tetrachloride in water, stir until homogeneous to obtain tin tetrachloride solution, and store in a refrigerator for later use; (2) Fe(OH)3 nanoparticles were placed in a muffle furnace for calcination at a temperature of 550℃~750℃ for 5h~7h. The Fe(OH)3 nanoparticles placed in the muffle furnace at 550℃~750℃ were then removed and immediately poured into a pre-prepared tin tetrachloride solution for quenching. After stirring, filtration and drying, Sn was obtained. q -Fe2O3 nanoparticles; (3) Dissolve soluble platinum nitrate in dilute hydrochloric acid, mix and stir until homogeneous to obtain platinum nitrate solution; (4) The obtained Sn q Fe2O3 nanoparticles were calcined in a muffle furnace at a temperature of 350℃~550℃ for 30min~60min; Sn was then placed at 350℃~550℃... q Fe₂O₃ nanoparticles were removed and immediately poured into a prepared platinum nitrate solution for quenching. After stirring, filtration, and drying, Pt was obtained. q / Sn q -Fe2O3 nanoparticles.

2. The Pt according to claim 1 q / Sn q The method for preparing Fe2O3 catalyst is characterized by, The concentration of the tin tetrachloride solution in step (1) is 0.2 mol / L to 0.8 mol / L.

3. The Pt according to claim 1 q / Sn q The method for preparing Fe2O3 catalyst is characterized by, The Fe(OH)3 nanoparticles in step (2) have a particle size of 30–120 nm.

4. The Pt according to claim 1 q / Sn q The method for preparing Fe2O3 catalyst is characterized by, The concentration of the platinum nitrate solution in step (3) is 0.3g. Pt / L~1.0g Pt / L.

5. The Pt according to claim 1 q / Sn q The method for preparing Fe2O3 catalyst is characterized by, Step (4) Pt q / Sn q The mass percentage concentration of Pt in Fe2O3 nanoparticles is 0.1%–0.9%.

6. The Pt according to claim 1 q / Sn q The method for preparing Fe2O3 catalyst is characterized by, The stirring time in steps (2) and (4) is 3 min to 5 min.

7. The Pt according to claim 1 q / Sn q The method for preparing Fe2O3 catalyst is characterized by, The drying temperature in steps (2) and (4) is 60℃~90℃, and the drying time is 8h~12h.

8. A Pt catalyst for efficient catalytic degradation of VOCs, prepared by the method according to any one of claims 1-7. q / Sn q -Fe2O3 catalyst.

9. The Pt as described in claim 8 for efficient catalytic degradation of VOCs q / Sn q - Application of Fe2O3 catalyst in the removal of volatile organic pollutants in the environment.

10. The application according to claim 9, characterized in that, The volatile organic pollutant is one or more of toluene and acetone.

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