Sulfur-tolerant platinum-based catalyst and preparation method thereof

Abstract

The invention discloses a sulfur-tolerant platinum-based catalyst and a preparation method thereof, and the preparation method of the sulfur-tolerant platinum-based catalyst comprises the following steps: weighing roasted ZrO2 as a carrier, weighing ammonium metatungstate, completely dissolving in deionized water, dropwise adding the solution until the carrier is completely immersed, and carrying out ultrasonic treatment; standing at room temperature, drying, and roasting in air at 500-600 DEG C to prepare a tungsten oxide loaded solid acid composite carrier WO3-ZrO2; and weighing chloroplatinic acid, completely dissolving the chloroplatinic acid in deionized water, dropwise adding the solution into the composite carrier, completely immersing the composite carrier, carrying out ultrasonic treatment, standing at room temperature, drying, and roasting in air at 250-350 DEG C to obtain the sulfur-tolerant platinum-based catalyst. The catalyst is simple in preparation method, has relatively strong tolerance to different sulfur species, and has good low-temperature catalytic performance and catalytic stability to low-carbon alkane.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation technology, specifically relating to a sulfur-resistant platinum-based catalyst and its preparation method. Background Technology

[0002] VOCs from coal chemical industry can be categorized into two types based on their source: organized emissions and fugitive emissions. Organized emissions refer to the regular, concentrated discharge of VOCs through exhaust stacks, while fugitive emissions refer to the leakage of organic matter during production due to the lack of sealed equipment or inadequate sealing measures. Fugitive emissions of VOCs are difficult to collect, and the emission volume and timing are uncertain, making them a key focus and challenge for VOCs control. Among these, the VOCs in the exhaust gas from coal conversion syngas purification units are characterized by complex composition, high proportion of short-chain hydrocarbons, wide concentration range, large volume, and high sulfur content, making them a difficult and challenging aspect of VOCs control in the coal chemical industry.

[0003] Low-carbon alkanes, due to their high CH bond energy and chemical stability, are difficult to activate and catalytically convert at low temperatures. Noble metal Pt catalysts generally exhibit high activity for the complete combustion of light alkanes and are considered typical catalysts for this purpose. Existing research has shown that supported Pt catalysts are often modified by adding transition metals such as W, V, and Mo to alter the Pt species state or the surface acidity of the support, thereby increasing the catalytic activity of the Pt catalyst. However, sulfur species in the exhaust gas can easily poison and deactivate the catalyst, and changes in operating conditions can lead to a significant decline in catalyst performance. Therefore, developing a platinum-based catalyst with good stability and strong tolerance to different sulfur groups is essential. Summary of the Invention

[0004] To address at least one of the above problems, the present invention provides a sulfur-resistant platinum-based catalyst and its preparation method.

[0005] To achieve the above objectives, the present invention employs the following technical means: The first aspect of this invention provides a method for preparing a sulfur-resistant platinum-based catalyst, comprising the following steps: S1. Preparation of WO3-ZrO2 support: Weigh calcined ZrO2 as support, weigh ammonium metatungstate, dissolve it completely in deionized water, and then add the solution dropwise until the support is completely submerged. Sonicate; let it stand at room temperature and then dry it. Calcine it in air at 500-600 ℃ to obtain WO3-ZrO2 solid acid composite support supported on tungsten oxide. S2. Weigh chloroplatinic acid, dissolve it completely in deionized water, and then add the solution dropwise to the composite support to completely immerse the composite support. Sonicate, let it stand at room temperature, dry it, and calcine it in air at 250-350 ℃ to obtain a sulfur-resistant platinum-based catalyst.

[0006] In some embodiments of the present invention, the ammonium metatungstate loading is 20-80 wt%, more preferably, the ammonium metatungstate loading is 60 wt%.

[0007] In some embodiments of the present invention, the loading of chloroplatinic acid is 1-2 wt%.

[0008] In some embodiments of the present invention, the drying temperature in steps S1 and S2 is 90-110 °C.

[0009] In some embodiments of the present invention, in step S1, the calcination temperature of the ZrO2 support is 500-600 °C.

[0010] In some embodiments of the present invention, the product is roasted for 3-5 hours in steps S1 and S2.

[0011] In some embodiments of the present invention, the ultrasound time in steps S1 and S2 is 50-70 min.

[0012] In some embodiments of the present invention, in steps S1 and S2, the standing time at room temperature is 20-25 h.

[0013] A second aspect of the present invention provides a sulfur-resistant platinum-based catalyst prepared by the method described in the first aspect.

[0014] The third aspect of the present invention provides the application of the sulfur-resistant platinum-based catalyst described in the second aspect in the low-temperature catalytic degradation of short-chain hydrocarbon VOCs pollution.

[0015] In some embodiments of the present invention, the short-chain hydrocarbon VOCs are propane.

[0016] In some embodiments of the present invention, the low temperature is a temperature of 175-260 °C.

[0017] The present invention also provides the application of the sulfur-resistant platinum-based catalyst described in the second aspect in the catalytic degradation of short-chain hydrocarbon VOCs pollution in sulfur-containing flue gas.

[0018] The present invention also provides the application of the sulfur-resistant platinum-based catalyst described in the second aspect in the catalytic degradation of short-chain hydrocarbon VOCs pollution in water-containing flue gas.

[0019] In some embodiments of the present invention, the sulfur atmosphere in the sulfur-containing flue gas includes SO2 atmosphere, H2S atmosphere, and COS atmosphere.

[0020] In some embodiments of the present invention, the temperature of the catalytic degradation is below 260 °C.

[0021] In some embodiments of the present invention, the catalyst is reduced at 250°C for 1 hour in an atmosphere with a concentration of 10% H2 before use.

[0022] Beneficial effects of the present invention Compared with the prior art, the present invention has the following beneficial effects: This invention provides a sulfur-resistant platinum-based catalyst. The catalyst is simple to prepare and the loading of tungsten and platinum can be controlled. The obtained catalyst can catalytically decompose low-carbon alkane-propane at temperatures as low as 177 °C, and has good low-temperature catalytic performance and catalytic stability.

[0023] The catalyst prepared by this method exhibits excellent sulfur and water resistance, and is resistant to sulfur atmospheres including SO2, H2S, and COS. It demonstrates strong tolerance to different sulfur species. In a sulfur-containing atmosphere, it can achieve complete degradation of short-chain hydrocarbon VOCs—propane—at a temperature of 260℃. Furthermore, the catalyst exhibits good high-temperature and long-term stability, showing broad application prospects in the catalytic degradation of short-chain hydrocarbon VOCs—propane—in sulfur-containing flue gas. Attached Figure Description

[0024] Figure 1 The catalytic degradation performance of propane by the catalysts prepared in Examples 1-5 of this invention is shown. Figure 2 The selectivity of the catalysts prepared in Examples 1-5 of this invention for catalyzing CO2 is shown; Figure 3 The high-temperature stability of the catalyst prepared in Example 4 of this invention is shown; Figure 4 The water resistance of the catalyst prepared in Example 4 of this invention is shown; Figure 5 The temperature curves of propane conversion under different sulfur atmospheres are shown for the catalyst prepared in Example 4 of this invention. Figure 6 The activity test of the catalyst prepared in Example 4 of the present invention for propane catalytic conversion after pretreatment in different sulfur atmospheres is shown. Figure 7 The long-term stability test of the catalyst prepared in Example 4 of this invention under a COS atmosphere is shown. Figure 8 The long-term stability test of the catalyst prepared in Example 4 of the present invention under H2S atmosphere is shown; Figure 9 The long-term stability test of the catalyst prepared in Example 4 of the present invention under SO2 atmosphere is shown. Detailed Implementation

[0025] The following examples are used to illustrate preferred embodiments of the invention. Those skilled in the art will understand that the techniques disclosed in the examples represent techniques discovered by the inventors that can be used to implement the invention, and therefore can be considered preferred embodiments for implementing the invention. However, those skilled in the art should understand from this specification that many modifications can be made to the specific embodiments disclosed herein, still yielding the same or similar results, without departing from the spirit or scope of the invention.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains, and all materials disclosed herein are incorporated herein by reference. Many equivalent techniques of specific embodiments of the invention described herein will be recognized or can be understood by those skilled in the art through conventional experimentation. These equivalents will be included in the claims.

[0027] The technical solution of this application will be further described in detail below with reference to specific embodiments.

[0028] Example 1: Preparation of 1% Pt / ZrO2 ZrO2 calcined at 600 °C for 4 hours in air was weighed and placed in a beaker as a support. Chloroplatinic acid was weighed at a loading of 1 wt%. After complete dissolution, the solution was added dropwise to the beaker until the liquid level just submerged the surface of the support. The mixture was then sonicated for 60 minutes. After removal, the mixture was placed at room temperature for 12 hours. Then, it was transferred to an oven at 105 °C for drying and calcined in air at 600 °C for 4 hours to obtain the catalyst: 1% Pt / ZrO2.

[0029] Example 2: Preparation of 1% Pt / W 20 -ZrO2 Step S1, Preparation of WO3-ZrO2 support: Weigh ZrO2 that has been calcined in air at 600 °C for 4 hours as a support and place it in a beaker. Weigh ammonium metatungstate at a loading of 20 wt% and completely dissolve it in deionized water. Add the solution dropwise into the beaker so that the liquid level just submerges the support and sonicate the surface for 60 min. Remove it and let it stand at room temperature for 12 h. Then transfer it to an oven at 105 °C to dry it and calcinate it in air at 600 °C for 4 h to obtain tungsten oxide supported solid acid composite support WO3-ZrO2.

[0030] Step S2: Weigh the composite support and spread it evenly in a 100 mL beaker. Weigh chloroplatinic acid according to a loading of 1 wt%, completely dissolve it in deionized water, and add the solution dropwise into the beaker to just submerge the composite support. Sonicate for 60 min, let it stand at room temperature for 12 h, then dry it overnight in an oven at 105 ℃. Transfer it to a muffle furnace at 300 ℃ and calcine it in air for 4 h to obtain the catalyst: 1% Pt / W 20 -ZrO2.

[0031] Example 3: Preparation of 1% Pt / W 40 -ZrO2 Step S1, Preparation of WO3-ZrO2 support: ZrO2 calcined at 600 °C for 4 hours in air was weighed and placed in a beaker as the support. Ammonium metatungstate was weighed according to a loading of 40 wt% and completely dissolved in deionized water. The solution was added dropwise to the beaker so that the liquid surface just submerged the support and the surface was sonicated for 60 min. After removal, it was placed at room temperature for 12 h and then transferred to an oven at 105 °C to dry. After calcination at 600 °C in air for 4 h, tungsten oxide-supported solid acid composite support WO3-ZrO2 was obtained.

[0032] Step S2: Weigh the composite support and spread it evenly in a 100 mL beaker. Weigh chloroplatinic acid according to a loading of 1 wt%, completely dissolve it in deionized water, and add the solution dropwise into the beaker to just submerge the composite support. Sonicate for 60 min, let it stand at room temperature for 12 h, then dry it overnight in an oven at 105 ℃. Transfer it to a muffle furnace at 300 ℃ and calcine it in air for 4 h to obtain the catalyst: 1% Pt / W 40 -ZrO2.

[0033] Example 4: Preparation of 1% Pt / W 60 -ZrO2 Step S1, Preparation of WO3-ZrO2 support: Weigh ZrO2 that has been calcined in air at 600 °C for 4 hours as a support and place it in a beaker. Weigh ammonium metatungstate according to a loading of 60 wt%, completely dissolve it in deionized water, add the solution dropwise into the beaker so that the liquid surface just submerges the support, and sonicate the surface for 60 min. After removing it, let it stand at room temperature for 12 h, then transfer it to an oven at 105 °C to dry, and then calcinate it in air at 600 °C for 4 h to obtain tungsten oxide supported solid acid composite support WO3-ZrO2.

[0034] Step S2: Weigh the composite support and spread it evenly in a 100 mL beaker. Weigh chloroplatinic acid according to the loading amount of 1 wt%, completely dissolve it in deionized water, and add the solution dropwise into the beaker to just submerge the composite support. Sonicate for 60 min, let it stand at room temperature for 12 h, and then dry it overnight in an oven at 105 ℃. Transfer it to a muffle furnace at 300 ℃ and calcine it in air for 4 h to obtain the catalyst: 1%Pt / W60-ZrO2.

[0035] Example 5: Preparation of 1% Pt / W 80 -ZrO2 Step S1, Preparation of WO3-ZrO2 support: Weigh ZrO2 that has been calcined in air at 600 °C for 4 hours as a support and place it in a beaker. Weigh ammonium metatungstate according to a loading of 80 wt%, completely dissolve it in deionized water, add the solution dropwise into the beaker so that the liquid surface just submerges the support, and sonicate the surface for 60 min. After removal, place it at room temperature for 12 h, then transfer it to an oven at 105 °C to dry, and then calcinate it in air at 600 °C for 4 h to obtain tungsten oxide supported solid acid composite support WO3-ZrO2.

[0036] Step S2: Weigh the composite support and spread it evenly in a 100 mL beaker. Weigh chloroplatinic acid according to a loading of 1 wt%, completely dissolve it in deionized water, and add the solution dropwise into the beaker to just submerge the composite support. Sonicate for 60 min, let it stand at room temperature for 12 h, then dry it overnight in an oven at 105 ℃. Transfer it to a muffle furnace at 300 ℃ and calcine it in air for 4 h to obtain the catalyst: 1% Pt / W 80 -ZrO2.

[0037] Performance testing (1) Catalytic degradation performance of propane by the catalysts prepared in Examples 1-5.

[0038] Test conditions: 2000 ppm propane, 2% O2 and residual nitrogen, catalyst dosage 0.1 g, where the propane conversion result is as follows: Figure 1 The results show that the addition of the transition metal tungsten can significantly improve the low-temperature activity of the catalyst for propane degradation. Among them, tungsten with a loading of 60% exhibits the best low-temperature performance and can achieve complete conversion of 2000 ppm propane at 200 °C.

[0039] (2) Selectivity of the catalysts prepared in Examples 1-5 for catalytic CO2.

[0040] The selective results for CO2 are as follows: Figure 2 As shown.

[0041] The results showed that the addition of the transition metal tungsten can significantly improve the low-temperature activity of the catalyst for CO2 selectivity. Among them, the addition of 60% tungsten showed the best low-temperature activity, and it was completely degraded into CO2 and H2O at 200 °C.

[0042] (3) High-temperature stability of the catalyst prepared in Example 4.

[0043] The high-temperature stability results of the catalyst are as follows: Figure 3 As shown.

[0044] Test conditions: 2000 ppm propane, 2% O2 and residual nitrogen, 1% Pt / W 60 - The amount of ZrO2 catalyst used was 0.1 g, the reaction temperature was 200 ℃ at low temperature and 600 ℃ at high temperature, the reaction time was 10 hours at each temperature, and the total reaction time was 50 hours.

[0045] The results showed that the catalyst's performance only fluctuated slightly during five consecutive high and low temperature temperature variations. After the temperature stabilized, it maintained good catalytic performance, demonstrating the catalyst's good stability during temperature variations.

[0046] (4) Water resistance of the catalyst prepared in Example 4.

[0047] Water resistance test results are as follows Figure 4 As shown.

[0048] Test conditions: 2000 ppm propane, 2% O2 and residual nitrogen, 1% Pt / W 60 - The amount of ZrO2 catalyst used was 0.1g, the total reaction time was 50 hours, and moisture resistance tests were conducted by introducing 5 vol % and 10 vol % water vapor respectively.

[0049] The results showed that the catalyst's performance was only slightly reduced in the water resistance test, and its performance could be fully recovered after the water vapor was removed, demonstrating good water resistance stability.

[0050] (5) Temperature curves of propane conversion under different sulfur atmospheres for the catalyst prepared in Example 4 are shown below. Figure 5 As shown.

[0051] Test conditions: 1% Pt / W 60The ZrO2 catalyst dosage was 0.1 g, the reaction heating rate was 5 ℃ / min, and the holding time at each temperature point was 30 minutes. Sulfur-free atmosphere test conditions: 2000 ppm propane, 2% O2, and residual nitrogen. SO2 / H2S / COS atmospheres were: 2000 ppm propane, 50 ppm SO2, 2% O2, and residual nitrogen; 2000 ppm propane, 50 ppm H2S, 2% O2, and residual nitrogen; 2000 ppm propane, 50 ppm COS, 2% O2, and residual nitrogen.

[0052] The results showed that the catalyst's catalytic activity for propane was enhanced in the SO2 atmosphere, while its catalytic performance was somewhat inhibited at low temperatures in the H2S and COS atmospheres, but it could still achieve complete conversion of propane at 260 °C.

[0053] (6) The activity test of the catalyst prepared in Example 4 on propane catalytic conversion after pretreatment in different sulfur atmospheres is as follows: Figure 6 As shown.

[0054] Test conditions: 1% Pt / W 60 The ZrO2 catalyst dosage was 0.1 g, the reaction heating rate was 5 °C / min, the holding time at each temperature was 30 minutes, and the reaction atmosphere was 2000 ppm propane, 2% O2, and residual nitrogen. The untreated catalyst was directly tested after hydrogen reduction. The SO2 / H2S / COS pretreated catalysts were treated at 120 °C for 1 hour under 50 ppm SO2 / H2S / COS and residual nitrogen, respectively.

[0055] The results showed that the catalyst performance was improved after SO2 / H2S / COS pretreatment, demonstrating good adaptability to sulfur atmosphere.

[0056] (7) The long-term stability test of the catalyst prepared in Example 4 under a COS atmosphere was as follows: Figure 7 As shown.

[0057] Test conditions: 1% Pt / W 60 The ZrO2 catalyst dosage was 0.1 g, and the reaction atmosphere was 2000 ppm propane, 50 ppm COS, 2% O2, and residual nitrogen. The reactions were carried out at 240 °C and 260 °C for 10 hours each. The results showed that the catalyst's performance decreased at 240 °C during the reaction, but did not decrease at 260 °C, demonstrating good tolerance to COS.

[0058] (8) The long-term stability test of the catalyst prepared in Example 4 under H2S atmosphere, the results are as follows: Figure 8 As shown.

[0059] Test conditions: 1% Pt / W 60 The ZrO2 catalyst was 0.1 g, and the reaction atmosphere was 2000 ppm propane, 50 ppm H2S, 2% O2, and residual nitrogen. The reaction was carried out at 240 °C and 260 °C for 10 hours, respectively.

[0060] The results showed that the catalyst's performance did not decrease during the 20-hour test at different temperatures, demonstrating good tolerance to H2S.

[0061] (9) The long-term stability test of the catalyst prepared in Example 4 under SO2 atmosphere, the results are as follows: Figure 9 As shown.

[0062] Test conditions: 1% Pt / W 60 The ZrO2 catalyst was 0.1 g, and the reaction atmosphere was 2000 ppm propane, 50 ppm SO2, 2% O2, and residual nitrogen. The reaction was carried out at 240 °C and 260 °C for 10 hours, respectively.

[0063] The results showed that the catalyst's performance did not decrease during the 20-hour test at different temperatures, demonstrating good tolerance to SO2.

[0064] All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. Furthermore, it should be understood that after reading the foregoing teachings of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by this application.

Claims

1. A method for preparing a sulfur-resistant platinum-based catalyst, characterized in that, Includes the following steps: S1. Preparation of WO3-ZrO2 support: Weigh calcined ZrO2 as support, weigh ammonium metatungstate, dissolve it completely in deionized water, and then add the solution dropwise until the support is completely submerged. Sonicate; let it stand at room temperature and then dry it. Calcine it in air at 500-600 ℃ to obtain WO3-ZrO2 solid acid composite support supported on tungsten oxide. S2. Weigh chloroplatinic acid, dissolve it completely in deionized water, and then add the solution dropwise to the composite support to completely immerse the composite support. Sonicate, let it stand at room temperature, dry it, and calcine it in air at 250-350 ℃ to obtain a sulfur-resistant platinum-based catalyst.

2. The method for preparing a sulfur-resistant platinum-based catalyst according to claim 1, characterized in that, The ammonium metatungstate loading is 20-80 wt%.

3. The method for preparing a sulfur-resistant platinum-based catalyst according to claim 1, characterized in that, The ammonium metatungstate loading is 60 wt%.

4. The method for preparing a sulfur-resistant platinum-based catalyst according to claim 1, characterized in that, The loading of chloroplatinic acid is 1-2 wt%.

5. The method for preparing a sulfur-resistant platinum-based catalyst according to claim 1, characterized in that, In steps S1 and S2, the drying temperature is 90-110 ℃.

6. The method for preparing a sulfur-resistant platinum-based catalyst according to claim 1, characterized in that, In step S1, the calcination temperature of the ZrO2 support is 500-600 ℃.

7. The method for preparing a sulfur-resistant platinum-based catalyst according to claim 6, characterized in that, In steps S1 and S2, the product is calcined for 3-5 hours.

8. The method for preparing a sulfur-resistant platinum-based catalyst according to claim 1, characterized in that, In steps S1 and S2, the ultrasound time is 50-70 min.

9. The method for preparing a sulfur-resistant platinum-based catalyst according to claim 1, characterized in that, In steps S1 and S2, the standing time at room temperature is 20-25 h.

10. A sulfur-resistant platinum-based catalyst, characterized in that: It is prepared by the method described in any one of claims 1-9.

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