Short-chain hydrocarbon VOCs catalytic degradation platinum-based catalyst and preparation method thereof

Abstract

The application discloses a preparation method of a short-chain hydrocarbon VOCs catalytic degradation platinum-based catalyst. Cobalt salt precursors and zirconium salt precursors with a molar ratio of 8-9:1 are dissolved in ultrapure water, and an organic acid solution is added under stirring, wherein the molar concentration of the organic acid solution is higher than that of the total metal salt solution. After the solution generates gel-like substances, the stirring is stopped, and the temperature is increased to 70-100 DEG C for drying overnight. The obtained solid material is ground and calcined in a muffle furnace. After cooling, a certain amount of product is weighed and dissolved in appropriate ultrapure water to obtain a carrier solution. The active noble metal platinum precursor salt solution is added dropwise into the carrier solution, and after sufficient stirring, the sample is dried overnight, calcined at 300-400 DEG C in air for 3-5 hours, and then reduced by a mixed gas of hydrogen and nitrogen. The catalyst prepared by the method has simple preparation, excellent sulfur resistance, and can catalytically decompose ethane at a temperature lower than 300 DEG C.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a platinum-based catalyst for the catalytic degradation of short-chain hydrocarbon VOCs and its preparation method. Background Technology

[0002] With social development and industrial progress, people's living standards are constantly improving. Volatile organic compounds (VOCs) emitted from industrial production and vehicle exhaust have become a key focus of environmental governance, seriously damaging the ecological environment and threatening human health. Ethane, a short-chain hydrocarbon VOC, is a saturated alkane with relatively large emissions and is currently a focus of attention for many researchers. However, due to its stable chemical properties, the catalytic degradation of ethane is more difficult than that of other oxygen-containing and unsaturated alkanes, necessitating effective treatment. Furthermore, in practical operating conditions, the presence of sulfur dioxide can adversely affect catalyst lifetime. Therefore, the preparation of a highly efficient catalyst for the catalytic degradation of ethane with good sulfur resistance has significant industrial application value.

[0003] Compared with transition metal oxide catalysts, noble metal catalysts have better catalytic activity and stability, and are more resistant to sulfur dioxide, making them the mainstream direction for catalyst development and application.

[0004] Currently, although a large amount of work has been done on noble metal catalysts for the catalytic degradation of short-chain hydrocarbon VOCs, the temperature at which existing catalysts can completely degrade ethane is generally above 300 °C, and low-temperature efficient degradation remains a challenge. At the same time, the stability and sulfur resistance of the catalysts also need further improvement. Therefore, it is essential to develop a sulfur-resistant, low-temperature efficient ethane catalyst with good low-temperature conversion activity and stability. Summary of the Invention

[0005] To address at least one of the above problems, the present invention provides a platinum-based catalyst for the catalytic degradation of short-chain hydrocarbon VOCs and its preparation method.

[0006] To achieve the above objectives, the present invention employs the following technical means:

[0007] The first aspect of this invention provides a method for preparing a platinum-based catalyst for the catalytic degradation of short-chain hydrocarbon VOCs, comprising the following steps:

[0008] (1) Dissolve the cobalt salt precursor and zirconium salt precursor in ultrapure water with a molar ratio of (8-9):1;

[0009] (2) At a certain temperature, the organic acid solution is added to the solution of (1) while stirring; the molar concentration of the organic acid solution is higher than the molar concentration of the total metal salt solution;

[0010] (3) After the solution in (2) produces a gel-like substance, stop stirring and raise the temperature to 70-100 ℃ to dry overnight;

[0011] (4) Grind the material obtained in (3) and place it in a muffle furnace and calcine it under air conditions for 3-5 hours;

[0012] (5) After the reaction is cooled to room temperature, a certain mass of the product in (4) is weighed as a carrier and dissolved in an appropriate amount of ultrapure water and stirred evenly to obtain a carrier solution.

[0013] (6) Add the active platinum precursor salt solution to the solution in (5), stir thoroughly, and dry overnight; the mass concentration of the added platinum precursor solution is 0.05-3 wt% of the carrier solution.

[0014] (7) The material obtained in (6) is calcined in air at 300-400 °C for 3-5 hours, cooled, and then reduced by a mixture of hydrogen and nitrogen to obtain the desired platinum-based catalyst.

[0015] Furthermore, the cobalt salt precursor and the zirconium salt precursor are nitrates, acetates or chlorides of cobalt or zirconium metals.

[0016] Furthermore, the organic acid in step (2) is citric acid or oxalic acid.

[0017] Furthermore, the temperature range for calcination in air in step (4) is 350-550 °C.

[0018] Further, in step (6), the mass concentration of the noble metal platinum precursor solution added is 0.5-2 wt% of the carrier solution; preferably, the mass concentration of the noble metal platinum precursor solution added is 1 wt% of the carrier solution.

[0019] Further, in step (7), the mixed gas is a mixture of 10 vol % hydrogen and 90 vol % nitrogen, and the flow rate of the mixed gas is 30-50 mL / min.

[0020] Furthermore, in step (7), the reduction temperature is 250-350 ℃.

[0021] A second aspect of the present invention provides a catalyst for the catalytic degradation of short-chain hydrocarbon VOCs, which is prepared by the method described in the first aspect.

[0022] The present invention also provides a catalyst prepared by replacing the active noble metal platinum with any one of palladium, ruthenium, or iridium, which can also catalytically decompose short-chain hydrocarbon VOCs ethane at temperatures below 300 °C.

[0023] A third aspect of the present invention provides the application of the catalyst described in the second aspect in the low-temperature catalytic degradation of short-chain hydrocarbon VOCs pollution in the atmosphere.

[0024] Further, the short-chain hydrocarbon VOCs are ethane; the low temperature is a temperature below 300 °C, and further, the low temperature is a temperature below 250 °C.

[0025] Beneficial effects of the present invention

[0026] Compared with existing technologies, this invention has the following advantages: This invention provides a catalyst for the catalytic degradation of short-chain hydrocarbon VOCs, specifically ethane. The catalyst is simple to prepare, and with a Co:Zr molar ratio of 9:1, it can catalytically decompose ethane at temperatures below 300 °C. After loading with an active noble metal, the ethane catalytic temperature is further reduced. Simultaneously, the catalyst prepared by this method exhibits excellent sulfur resistance and improved water resistance. In particular, the Co9Zr1 catalyst loaded with 1 wt% Pt can still maintain a conversion rate above 80% in sulfur-containing environments, demonstrating outstanding sulfur resistance. This catalyst fully degrades ethane at low temperatures and exhibits good stability and sulfur resistance, showing broad application prospects in the catalytic degradation of short-chain hydrocarbon VOCs (ethane) in sulfur-containing flue gas. Attached Figure Description

[0027] Figure 1 The comparison of the catalytic effects of the catalysts prepared in Examples 1-3 of this invention on ethane is shown.

[0028] Figure 2 The comparison of the catalytic effects of the catalysts prepared in Examples 1, 4-5 and Comparative Example 1 on ethane is shown.

[0029] Figure 3 The comparison of the catalytic effects of the catalysts prepared in Examples 4 and 6 of this invention on ethane is shown.

[0030] Figure 4 The comparison of the catalytic effects of the catalysts prepared in Examples 4 and 7-8 of the present invention on ethane is shown.

[0031] Figure 5 The comparison of the catalytic effects of the catalysts prepared in Examples 9-12 of this invention on ethane is shown;

[0032] Figure 6 The comparison of the catalytic effects of the catalysts prepared in Examples 9 and 13-14 of this invention on ethane is shown.

[0033] Figure 7The comparison of the catalytic effects of the catalysts prepared in Example 9 and Comparative Example 2 on ethane is shown.

[0034] Figure 8 The catalysts prepared in Examples 4 and 9 of this invention are shown, and their water resistance is compared.

[0035] Figure 9 The catalysts prepared in Examples 4, 9, 3, and 4 of this invention are shown, and their sulfur resistance performance is compared. Detailed Implementation

[0036] 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.

[0037] 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 and cited therein are incorporated herein by reference. Many equivalent techniques of specific embodiments of the invention described herein will be recognized or can be understood by ordinary experimentation by those skilled in the art. These equivalents will be included in the claims.

[0038] The technical solution of this application will be further described in detail below with reference to specific embodiments.

[0039] A method for preparing a platinum-based catalyst for the catalytic degradation of short-chain hydrocarbon VOCs includes the following steps:

[0040] (1) Dissolve the cobalt salt precursor and the zirconium salt precursor in ultrapure water with a molar ratio of (8-9):1; wherein the cobalt salt precursor and the zirconium salt precursor are nitrates, acetates or chlorides of cobalt and zirconium metals;

[0041] (2) At a certain temperature, an organic acid solution is added to the solution in (1) while stirring; wherein, the molar concentration of the organic acid solution is higher than the molar concentration of the total metal salt solution; the organic acid is citric acid or oxalic acid;

[0042] (3) After the solution in (2) produces a gel-like substance, stop stirring and raise the temperature to 70-100 ℃ to dry overnight;

[0043] (4) After grinding the material obtained in (3), place it in a muffle furnace and calcine it at 350-550 ℃ under air conditions for 3-5 h;

[0044] (5) After the reaction is cooled to room temperature, a certain mass of the product in (4) is weighed as a carrier and dissolved in an appropriate amount of ultrapure water and stirred evenly to obtain a carrier solution.

[0045] (6) A certain concentration of active platinum precursor salt solution is added dropwise to the solution in (5), stirred for 1 h, and then dried overnight; wherein, the mass concentration of the active platinum precursor solution added dropwise is 0.05-3 wt% of the carrier solution; preferably, the mass concentration of the platinum precursor solution added dropwise is 0.5-2 wt% of the carrier solution;

[0046] (7) The dried sample from (6) is first calcined in air at 300 °C for 3 hours, then cooled and reduced by a mixture of 10 vol % hydrogen and 90 vol % nitrogen for 1 hour to obtain the desired platinum-based catalyst. The flow rate of hydrogen is 30-50 mL / min and the reduction temperature is 250-350 °C.

[0047] In the above method, the active precious metal platinum can be replaced by any one of palladium, ruthenium, or iridium.

[0048] The present invention also provides a platinum-based catalyst for the catalytic degradation of short-chain hydrocarbon VOCs prepared by the method described above.

[0049] This invention also provides an application of the catalyst described above in the low-temperature catalytic degradation of short-chain hydrocarbon VOCs pollution in the atmosphere; the short-chain hydrocarbon VOCs are ethane; the low temperature is a temperature below 300 °C.

[0050] Example 1: Preparation of Co5Zr5 catalyst

[0051] The preparation method is as follows:

[0052] (1) Dissolve 5 mmol of cobalt nitrate hexahydrate and 5 mmol of zirconium nitrate pentahydrate in 20 mL of ultrapure water and stir until homogeneous;

[0053] (2) Dissolve 15 mmol of anhydrous citric acid in 15 mL of ultrapure water and stir until homogeneous. Add the citric acid solution dropwise into the solution of (1) while stirring at 60 °C.

[0054] (3) After the solution in (2) produces a gel-like substance, stop stirring and raise the temperature to 90 °C to dry overnight;

[0055] (4) Grind the material obtained in (3) and place it in a muffle furnace. Then, calcine it at 350 °C for 4 hours under air conditions to obtain the desired Co5Zr5 catalyst.

[0056] Example 2 Preparation of Co5Al5 catalyst

[0057] The preparation method is the same as in Example 1, except that zirconium nitrate pentahydrate is replaced with aluminum nitrate nonahydrate.

[0058] Example 3 Preparation of Co5Fe5 catalyst

[0059] The preparation method is the same as in Example 1, except that zirconium nitrate pentahydrate is replaced with ferric nitrate nonahydrate.

[0060] Example 4 Preparation of Co9Zr1 catalyst

[0061] The preparation method is the same as in Example 1, except that the materials in step (1) are 9 mmol of cobalt nitrate hexahydrate and 1 mmol of zirconium nitrate pentahydrate.

[0062] Example 5 Preparation of Co7Zr3 catalyst

[0063] The preparation method is the same as in Example 4, except that the materials in step (1) are 7 mmol of cobalt nitrate hexahydrate and 3 mmol of zirconium nitrate pentahydrate.

[0064] Example 6: Preparation of Co9Zr1 catalyst from oxalic acid

[0065] The preparation method is the same as in Example 4, except that citric acid in step (2) is replaced with oxalic acid.

[0066] Example 7 Preparation of Co9Zr1 catalyst at 450 °C

[0067] The preparation method is the same as in Example 4, except that the temperature in step (4) is 450 °C.

[0068] Example 8: Preparation of Co9Zr1 catalyst at 550 °C

[0069] The preparation method is the same as in Example 4, except that the temperature in step (4) is 550 °C.

[0070] Example 9 Preparation of Co9Zr1 catalyst supported on 1 wt% Pt

[0071] The preparation method is as follows:

[0072] (1) Weigh the required mass of the Co9Zr1 catalyst from Example (4) as a support and dissolve it in an appropriate amount of ultrapure water and stir until homogeneous;

[0073] (2) A certain amount of the noble metal platinum precursor solution is added dropwise to the solution in (2), stirred for 1 h, and then dried overnight; wherein the mass concentration of the noble metal platinum precursor solution added dropwise is 1 wt% of the carrier solution.

[0074] (3) The material obtained in (2) is first calcined in air at 300 °C for 3 hours, and after cooling, it is reduced by a mixture of 10 vol% hydrogen and 90 vol% nitrogen for 1 hour to obtain 1wt% Pt-Co9Zr1 catalyst. The flow rate of the mixed gas is 50 mL / min and the reduction temperature is 300 °C.

[0075] Example 10 Preparation of Co9Zr1 catalyst supported with 1 wt% Ir

[0076] The preparation method is the same as in Example 9, except that the noble metal platinum precursor solution in step (5) is replaced with the noble metal iridium precursor.

[0077] Example 11 Preparation of Co9Zr1 catalyst supported on 1 wt% Ru

[0078] The preparation method is the same as in Example 9, except that the noble metal platinum precursor solution in step (5) is replaced by the noble metal ruthenium precursor.

[0079] Example 12 Preparation of Co9Zr1 catalyst supported on 1 wt% Pd

[0080] The preparation method is the same as in Example 9, except that the noble metal platinum precursor solution in step (5) is replaced by the noble metal palladium precursor.

[0081] Example 13 Preparation of Co9Zr1 catalyst supported on 0.5 wt% Pt

[0082] The preparation method is the same as in Example 9, except that the concentration of the noble metal platinum precursor solution in step (5) is 0.5 wt% of the carrier solution.

[0083] Example 14 Preparation of Co9Zr1 catalyst supported on 1.5 wt% Pt

[0084] The preparation method is the same as in Example 9, except that the concentration of the noble metal platinum precursor solution in step (5) is 1.5 wt% of the carrier solution.

[0085] Comparative Example 1: Preparation of ZrO2 catalyst

[0086] The preparation method is the same as in Example 4, except that the material in step (1) is replaced with 10 mmol zirconium nitrate pentahydrate.

[0087] Comparative Example 2: Preparation of a 1wt% PtCo9Zr1 supported catalyst without reduction

[0088] The preparation method is the same as in Example 9, except that the hydrogen reduction step is not performed.

[0089] Comparative Example 3: 1 wt% Pt-Co3O4 catalyst

[0090] The preparation method is the same as in Example 4, except that the material in step (1) is replaced with 10 mmol of cobalt nitrate hexahydrate.

[0091] Comparative Example 4: Co3O4 catalyst

[0092] The preparation method is the same as in Example 9, except that the material in step (1) is replaced by the Co3O4 catalyst in Comparative Example 3.

[0093] We conducted ethane catalysis experiments using the catalysts prepared in Examples 1-14 and Comparative Examples 1-4, and the test results are shown in Table 1.

[0094] Table 1 Catalytic effects of catalysts obtained in Examples 1-15 and Comparative Examples 1-4

[0095]

[0096] (1) Examples 1-3 are catalysts prepared by Co with different metals, and their effects on ethane conversion are as follows: Figure 1 As shown.

[0097] The results showed that the catalysts prepared by cobalt with different metals had lower catalytic temperatures, with the catalyst obtained by combining cobalt with zirconium being the most advanced.

[0098] (2) The catalysts prepared in Examples 1, 4-5 and Comparative Example 1 were compared in terms of their ethane conversion effects. Figure 2 As shown.

[0099] The results showed that the catalytic efficiency of ethane was extremely low when there was no cobalt in the catalyst. The catalysts obtained by combining cobalt and zirconium in different ratios significantly improved the catalytic efficiency of ethane. Furthermore, the catalyst obtained by combining cobalt and zirconium in a 9:1 ratio had a lower catalytic temperature.

[0100] (3) The catalysts prepared in Example 4 and Example 6 show a comparison of their effects on ethane conversion. Figure 3 As shown.

[0101] The results showed that the acid solution had little effect on the catalytic performance of the Co9Zr1 catalyst when different acid solutions were used for its preparation.

[0102] (4) The catalysts prepared in Examples 4 and 7-8 were compared in terms of their ethane conversion effect. Figure 4 As shown.

[0103] The results showed that when the Co9Zr1 catalyst was prepared at different temperatures, the catalytic performance of the Co9Zr1 catalyst increased with increasing temperature, but the catalytic temperature was below 300 ℃.

[0104] (5) The catalysts prepared in Examples 9-12 were compared in terms of their ethane conversion effect. Figure 5 As shown.

[0105] The results showed that when different noble metals were used to support the Co9Zr1 catalyst, the catalytic temperature of the Co9Zr1 catalyst with noble metals was found to be below 300 ℃, while the catalytic temperature of the noble metals Pt and Pd supported was below 250 ℃. Furthermore, the catalytic temperature of the noble metal Pt supported was lower than that of the noble metal Pd.

[0106] (6) The catalysts prepared in Examples 9-13-14 were compared in terms of their ethane conversion effect. Figure 6 As shown.

[0107] The results showed that when comparing the catalytic performance of the precious metal Pt with different loading amounts, the Co9Zr1 loaded with 1 wt% Pt had the better catalytic performance and the catalytic temperature was 242 ℃.

[0108] (7) The catalysts prepared in Example 9 and Comparative Example 2 show a comparison of their effects on ethane conversion. Figure 7 As shown.

[0109] The results show that using hydrogen for reduction during the loading of noble metals can further improve the low-temperature catalytic performance of the catalyst.

[0110] (8) The catalysts prepared in Examples 4 and 9, when inoculated with 5 vol% H2O during the catalytic conversion of ethane, showed the following catalytic conversion effect: Figure 8 As shown.

[0111] The results showed that the Co9Zr1 catalyst loaded with 1 wt% Pt had better water resistance than the Co9Zr1 catalyst without Pt.

[0112] (9) The catalysts prepared in Examples 4, 9, Comparative Examples 3 and 4, when inoculated with 50 ppm SO2 during the catalytic conversion of ethane, showed the following catalytic conversion effect: Figure 9 As shown.

[0113] The results showed that the addition of zirconium increased the catalyst's sulfur resistance. Without zirconium, the catalyst would deactivate rapidly. With the addition of zirconium, the loading of precious metals further improved the catalyst's sulfur resistance. The Co9Zr1 catalyst loaded with 1 wt% Pt maintained a conversion rate of over 80% in a sulfur-containing environment, demonstrating outstanding sulfur resistance.

[0114] 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 platinum-based catalyst for the catalytic degradation of short-chain hydrocarbon VOCs, characterized in that, Includes the following steps: (1) Dissolve the cobalt salt precursor and zirconium salt precursor in ultrapure water with a molar ratio of (8-9):1; (2) At a certain temperature, the organic acid solution is added to the solution of (1) while stirring; the molar concentration of the organic acid solution is higher than the molar concentration of the total metal salt solution; (3) After the solution in (2) produces a gel-like substance, stop stirring and raise the temperature to 70-100 ℃ to dry overnight; (4) Grind the material obtained in (3) and place it in a muffle furnace and calcine it under air conditions for 3-5 hours; (5) After the reaction is cooled to room temperature, a certain mass of the product in (4) is weighed and dissolved in an appropriate amount of ultrapure water and stirred evenly to obtain a carrier solution; (6) Add the active precious metal platinum precursor salt solution dropwise to the solution in (5), stir thoroughly, and dry overnight; the loading of the active precious metal platinum is 0.05-3 wt%; (7) The material obtained in (6) is calcined in air at 300-400°C for 3-5 hours, cooled, and then reduced by a mixture of hydrogen and nitrogen to obtain the desired platinum-based catalyst.

2. The method for preparing a platinum-based catalyst for the catalytic degradation of short-chain hydrocarbon VOCs according to claim 1, characterized in that, The cobalt salt precursor and zirconium salt precursor are nitrates, acetates or chlorides of cobalt and zirconium metals.

3. The method for preparing a platinum-based catalyst for the catalytic degradation of short-chain hydrocarbon VOCs according to claim 1, characterized in that, The organic acid in step (2) is citric acid or oxalic acid.

4. The method for preparing a platinum-based catalyst for the catalytic degradation of short-chain hydrocarbon VOCs according to claim 1, characterized in that, In step (4), the temperature range for baking in air is 350-550 ℃.

5. The method for preparing a platinum-based catalyst for the catalytic degradation of short-chain hydrocarbon VOCs according to claim 1, characterized in that, In step (6), the loading of the active precious metal platinum is 0.5-2 wt%.

6. The method for preparing a platinum-based catalyst for the catalytic degradation of short-chain hydrocarbon VOCs according to claim 1, characterized in that, In step (7), the mixed gas is a mixture of 10 vol % hydrogen and 90 vol % nitrogen, and the flow rate of the mixed gas is 30-50 mL / min; the reduction temperature is 250-350 ℃.

7. A catalyst for the catalytic degradation of short-chain hydrocarbon VOCs, characterized in that: It is prepared by the method described in any one of claims 1-6.

8. The catalyst for the catalytic degradation of short-chain hydrocarbon VOCs according to claim 7, characterized in that: In the method, the active precious metal platinum is replaced by any one of palladium, ruthenium, or iridium.

9. The application of the catalyst according to any one of claims 7-8 in the low-temperature catalytic degradation of short-chain hydrocarbon VOCs pollution in the atmosphere.

10. The application according to claim 9, characterized in that: The short-chain hydrocarbon VOCs are ethane; the low temperature is a temperature below 300 °C.

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