Platinum-lead alloy catalyst and preparation method and application thereof

Abstract

The invention discloses a platinum-lead alloy catalyst and a preparation method and application thereof. The chemical formula of the platinum-lead alloy catalyst is PtPb / ZnO, and in the structure of the platinum-lead alloy catalyst, an active substance platinum-lead alloy is dispersed on the surface of a carrier zinc oxide. The platinum-lead alloy catalyst has an efficient catalytic effect in the process of preparing propylene through photocatalytic propane dehydrogenation, and the photocatalytic reaction has a high production rate (1 mmol g <-1 > h <-1 > or above, preferably 5 mmol g <-1 > h <-1 > or above) and selectivity of the product propylene.

Description

Technical Field

[0001] The present invention relates to the technical field of photocatalysis. More specifically, it relates to a platinum-lead alloy catalyst and its preparation method and application. Background Art

[0002] Propylene is an important chemical raw material and has a wide range of uses in the global chemical industry. Starting from propylene, a variety of chemical products such as polypropylene, acrylonitrile, and propylene oxide can be produced, and its demand has been increasing year by year. In recent decades, the discovery and exploitation of shale gas have attracted wide attention to the production of propylene by propane dehydrogenation. The rate-determining step of the propane dehydrogenation reaction is the activation dissociation of the propane C-H bond. Since the propane C-H bond energy is 401.3 kJ·mol -1 , a large amount of energy is required to drive its dissociation. Therefore, there is an urgent need to develop a catalyst that can drive the activation dissociation of the propane C-H bond under mild conditions and can efficiently catalyze the propane dehydrogenation reaction to produce propylene. Photocatalysis is a "zero-energy consumption" technology, that is, the semiconductor photocatalyst is photoexcited to generate photogenerated electrons and photogenerated holes to drive the reduction end and oxidation end of the chemical reaction respectively. Recently, platinum-based photocatalysts have been used in a series of alkane conversion processes including propane dehydrogenation, achieving efficient activation of the C-H bond in alkanes or alkyl groups and high selectivity of products under mild conditions, thus proving that semiconductor-supported platinum species can efficiently drive the photocatalytic activation dissociation of alkane C-H bonds. However, the catalytic performance of the existing platinum-based photocatalytic propane dehydrogenation catalysts is generally low, and the propylene production rate does not exceed 1 mmol g -1 h -1 , so there is an urgent need to modify the existing platinum-based photocatalytic propane dehydrogenation catalysts to improve the propylene production performance. Summary of the Invention

[0003] Based on the above problems, the purpose of the present invention is to provide a platinum-lead alloy catalyst and its preparation method and application. When the platinum-lead alloy catalyst is used in the process of photocatalytic propane dehydrogenation to produce propylene, it has an efficient catalytic effect, and the photocatalytic reaction has a high production rate (1 mmol g -1 h -1 or more, preferably 5 mmol g -1 h -1 or more) and selectivity of the product propylene.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions:

[0005] On the one hand, the present invention provides a platinum-lead alloy catalyst, and the chemical formula of the platinum-lead alloy catalyst is PtPb / ZnO. In the structure of the platinum-lead alloy catalyst, the active substance platinum-lead alloy is dispersed on the surface of the carrier zinc oxide.

[0006] Further, in the structure of the platinum-lead alloy catalyst, the platinum-lead alloy is dispersedly combined on the surface of the zinc oxide through chemical bonds.

[0007] Further, the mass ratio of the platinum-lead alloy to zinc oxide is 1-2%.

[0008] In the platinum-lead alloy catalyst, the carrier is selected as ZnO and the active ingredient is the platinum-lead alloy, which can endow the photocatalytic dehydrogenation of propane to prepare propylene with activity and propylene selectivity superior to other carriers.

[0009] In a second aspect, the present invention provides a preparation method of the platinum-lead alloy catalyst as described in the first aspect above. The preparation method includes the following steps:

[0010] Dissolve zinc salt and lead salt in deionized water to obtain solution A;

[0011] Dissolve sodium carbonate in deionized water to obtain solution B;

[0012] Dropwise mix solution A and solution B while controlling the pH to be 8.0-8.5 to obtain a crude product;

[0013] Wash and freeze-dry the crude product to obtain a precursor material;

[0014] In an air atmosphere, heat the precursor material and maintain it at this temperature, and then cool it to room temperature to obtain lead-modified zinc oxide;

[0015] Uniformly disperse the lead-modified zinc oxide and chloroplatinic acid hexahydrate in deionized water and stir to obtain an impregnated crude product;

[0016] Centrifuge and dry the impregnated crude product to obtain a platinum-impregnated product;

[0017] In a hydrogen-argon mixed atmosphere, heat the platinum-impregnated product and then cool it to room temperature to obtain the platinum-lead alloy catalyst.

[0018] In the above preparation method, in solution B, the role of sodium carbonate is to provide carbonate ions for the subsequent coprecipitation of Zn 2+ and Pb 2+ to prepare the crude product.

[0019] In the research process of the present invention, it is found that compared with other platinum precursors, chloroplatinic acid hexahydrate is suitable for introducing Pt by aqueous phase impregnation. As a platinum precursor, it can endow the obtained platinum-lead alloy catalyst with excellent catalytic effect for photocatalytic dehydrogenation of propane to prepare propylene. Common platinum precursors also include sodium chloroplatinate and platinum acetylacetonate. However, sodium chloroplatinate contains sodium ions, and the sodium ions may be adsorbed on the surface of the product and are not easy to remove after impregnation, affecting the subsequent catalytic performance; platinum acetylacetonate is insoluble in water, so it is only used as a precursor of Pt in organic phase synthesis.

[0020] Further, in the process of preparing lead-modified zinc oxide, the conditions for heating the precursor material and holding the temperature are as follows: heating at a rate of 5 - 6 °C·min -1 to 400 - 410 °C (preferably 400 °C) and holding at this temperature for 2 - 2.5 h.

[0021] Further, the conditions for heating the platinum-impregnated product are as follows: heating at a rate of 5 - 6 °C·min -1 to 300 - 500 °C and holding at this temperature for 2 - 2.5 h.

[0022] Further, the temperature after heating the platinum-impregnated product is 400 - 500 °C. Under this condition, the platinum-lead alloy catalyst has a more efficient catalytic effect for photocatalytic dehydrogenation of propane to prepare propylene, and the production rate of the product propylene in this photocatalytic reaction can reach 3 mmol g -1 h -1 or more.

[0023] Furthermore, the temperature after heating the platinum-impregnated product is 500 °C. Under this condition, the platinum-lead alloy catalyst has a more efficient catalytic effect for photocatalytic dehydrogenation of propane to prepare propylene, and the production rate of the product propylene in this photocatalytic reaction can reach 5 mmol g -1 h -1 or more.

[0024] Further, in the hydrogen-argon mixed atmosphere, the volume ratio of hydrogen to argon is 1:(9 - 10).

[0025] By controlling the heating reaction in the hydrogen-argon mixed atmosphere, it is possible to reduce Pt in chloroplatinic acid and Pb introduced by precipitation with hydrogen at high temperature and carry out the alloying process of Pt and Pb.

[0026] Further, in the solution A, the concentration of the zinc salt is 1.2 - 1.6 mol·L -1 , and the concentration of the lead salt is 2.6 - 3.0 mmol·L -1 . By controlling the concentration and relative dosage of each salt in the solution A, excellent activity and propylene selectivity for photocatalytic dehydrogenation of propane to prepare propylene can be imparted.

[0027] Further, the zinc salt is selected from zinc nitrate, and the lead salt is selected from lead nitrate.

[0028] Further, in the solution B, the concentration of sodium carbonate is 0.6 - 1.0 mol·L -1 .

[0029] Further, the volume ratio of the solution A to the solution B is (15 - 16):(45 - 55).

[0030] Furthermore, the temperature of the lyophilization is -50 to -47 °C, the pressure is 5 to 10 Pa, and the time is 24 to 48 h, preferably 24 h.

[0031] Furthermore, the chemical formula of the precursor material is Pb x Zn5(OH) 6+2x (CO3)2, where 0.009 ≤ x ≤ 0.011.

[0032] Furthermore, the molar ratio of zinc, lead in the lead-modified zinc oxide to chloroplatinic acid hexahydrate is (18 - 24):(0.039 - 0.045):(0.078 - 0.090).

[0033] Furthermore, the temperature of the drying is 60 to 70 °C, the time is 24 to 48 h, preferably 24 h.

[0034] Furthermore, in the above preparation method, the salts and precipitants used are all of analytical purity.

[0035] In the third aspect, the present invention provides the application of the platinum-lead alloy catalyst as described in the first aspect above in the photocatalytic dehydrogenation of propane to prepare propylene.

[0036] Furthermore, the application includes the following steps:

[0037] Under the protection of an inert gas, propane is introduced into a closed reaction kettle with a light-transmitting quartz glass window added with a platinum-lead alloy catalyst, and the reaction is carried out under light irradiation conditions.

[0038] In the above application, the functions of the light-transmitting quartz glass window include: as a light-transmitting component, the light of the light source passes through the quartz glass window and shines on the surface of the platinum-lead alloy catalyst to drive the photocatalytic dehydrogenation reaction of propane.

[0039] Furthermore, the volume ratio of propane to the inert gas is 5:95.

[0040] Furthermore, the inert gas is argon.

[0041] Furthermore, the gas pressure in the reaction kettle is 0.1 to 0.121 MPa.

[0042] Furthermore, the light source of the light irradiation is ultraviolet light, preferably ultraviolet light of 365 nm.

[0043] Unless otherwise specified, the raw materials used in the present invention can be obtained through commercial purchase, and any range described in the present invention includes the end values and any numerical values between the end values, as well as any sub-range constituted by any numerical value between the end values or the end values.

[0044] The beneficial effects of the present invention are as follows:

[0045] The platinum-lead alloy catalyst provided by the present invention is used in the catalytic preparation of propylene from propane, realizing the use of the platinum-lead alloy catalyst in the photocatalytic dehydrogenation of propane to prepare propylene, and the propylene production rate reaches 5 mmol g -1 h -1 level, and has high selectivity. The platinum-lead alloy catalyst of the present invention is expected to be applied to industrial production.

[0046] The preparation method of the platinum-lead alloy catalyst of the present invention is simple and the process is simple, which is easy for large-scale production. In this preparation method, a platinum-lead alloy is formed by equal-volume impregnation and high-temperature reduction annealing. In this preparation method, the activity of the obtained platinum-lead alloy catalyst in the photocatalytic dehydrogenation of propane to prepare propylene can be further optimized by controlling the amount of lead salt added when preparing the precursor material. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The following further describes the specific embodiments of the present invention in detail with reference to the accompanying drawings.

[0048] Figure 1 Shows the XRD pattern of the platinum-lead alloy catalyst obtained in Example 1 of the present invention.

[0049] Figure 2 Shows the Pt 4f XPS spectrum of the platinum-lead alloy catalyst obtained in Example 1 of the present invention.

[0050] Figure 3 Shows the transmission electron microscope image of the platinum-lead alloy catalyst obtained in Example 1 of the present invention.

[0051] Figure 4 Shows the energy spectrum of the transmission electron microscope element distribution of the platinum-lead alloy catalyst obtained in Example 1 of the present invention

[0052] Figure 5 Shows the precursor material (Pb x Zn5(OH) 6+2x (CO3)2) obtained in step 2) of Example 1 of the present invention.

[0053] Figure 6 Shows the performance graph of the photocatalytic dehydrogenation of propane to prepare propylene reaction cycle stability of the platinum-lead alloy catalyst obtained in Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0054] To more clearly illustrate the present invention, the present invention will be further described below with reference to the preferred embodiments and the accompanying drawings. Similar components in the drawings are denoted by the same reference numerals. Those skilled in the art should understand that the following specifically described content is illustrative rather than restrictive, and should not be used to limit the protection scope of the present invention.

[0055] In the following embodiments, the preparation method is a conventional method unless otherwise specified. The raw materials used can be obtained from public commercial channels unless otherwise specified, and the percentages are mass percentages unless otherwise specified.

[0056] Example 1

[0057] A preparation method of a platinum-lead alloy catalyst for photocatalytic propane dehydrogenation to prepare propylene includes the following steps:

[0058] 1) Prepare a mixed metal salt solution and a sodium carbonate solution: Dissolve 20 mmol of zinc nitrate hexahydrate and 0.04 mmol of lead nitrate in 15 mL of deionized water; dissolve 40 mmol of sodium carbonate in 50 mL of deionized water.

[0059] 2) Prepare the precursor material of the catalyst by coprecipitation method: Slowly add the mixed metal salt solution and the sodium carbonate solution prepared in step 1 drop by drop into a round-bottom flask containing 100 mL of deionized water. After controlling the pH to 8.5, continue adding until the mixed metal salt solution is completely added to obtain a crude product.

[0060] 3) Wash the crude product obtained in step 2 three times with deionized water, and then dry it in a freeze dryer at a temperature of -50 °C and a pressure of 5-10 Pa for 24 h to obtain the precursor material.

[0061] 4) Take the precursor material obtained in step 3, and in an air atmosphere, heat it at a heating rate of 5 °C·min -1 to 400 °C, hold for 2 h, and then naturally cool to room temperature to obtain lead-modified zinc oxide.

[0062] 5) Uniformly disperse the lead-modified zinc oxide obtained in step 4 and 43.2 mg of chloroplatinic acid hexahydrate in 30 mL of deionized water, and stir for 10 h to obtain an impregnated crude product.

[0063] 6) Centrifuge the impregnated crude product obtained in step 5, and then dry it in an oven at 60 °C for 24 h to obtain the platinum-impregnated product.

[0064] 7) Heat the platinum-impregnated product obtained in step 6 in a hydrogen-argon mixed atmosphere (10% H2, v / v) at a heating rate of 5 °C·min -1 to 500 °C, hold for 2 h, and then naturally cool to room temperature to obtain the platinum-lead alloy catalyst for photocatalytic propane dehydrogenation to prepare propylene, denoted as PtPb / ZnO-500.

[0065] Apply the platinum-lead alloy catalyst prepared by the above method to photocatalytic propane dehydrogenation to prepare propylene, which specifically includes the following steps:

[0066] In a sealed reactor with a volume of 56 mL and a light-transmitting quartz glass window, 5 mg of a platinum-lead alloy catalyst was added, and a certain proportion of propane (the volume ratio of propane to argon was 5:95) was introduced. The pressure inside the container was 0.121 MPa, and the reaction was carried out under 365 nm ultraviolet light for 1 h. The products were detected by gas chromatography. The activity of the catalyst was measured.

[0067] The platinum-lead alloy catalyst prepared in this example was characterized as follows:

[0068] Figure 1 XRD pattern of the platinum-lead alloy catalyst prepared in Example 1. It can be seen from the figure that the phase of ZnO appears.

[0069] Figure 2 4f XPS spectrum of Pt obtained in Example 1. From Figure 2 it can be seen that Pt in the catalyst is mainly in the 0 valence state.

[0070] Figure 3 Transmission electron microscopy image of the platinum-lead alloy catalyst obtained in Example 1. From Figure 3 it can be seen that there are a large number of particles on the surface of the catalyst, which are dispersed on the ZnO support.

[0071] Figure 4 Energy-dispersive X-ray spectroscopy elemental distribution map of the transmission electron microscopy of the platinum-lead alloy catalyst obtained in Example 1. From Figure 4 it can be seen that the large number of particles on the surface of the catalyst are platinum-lead alloy particles.

[0072] Figure 5 XRD pattern of the precursor material (Pb x Zn5(OH) 6+2x (CO3)2) obtained in step 3) of Example 1 is shown.

[0073] The catalytic performance of the platinum-lead alloy catalyst is shown in Table 1 below. It can be seen from Table 1 that the production rate of propylene is 5448.7 μmol g -1 h -1 , and the selectivity of propylene is 99.56%.

[0074] Table 1 Photocatalytic performance of PtPb / ZnO-500

[0075]

[0076] Figure 6 Performance graph of the photocatalytic propane dehydrogenation to prepare propylene reaction cycle stability of the platinum-lead alloy catalyst obtained in Example 1. It can be concluded from the figure that under the condition of cyclic gas charging, the production rate of propylene and the selectivity of propylene can be maintained at a relatively high level within 5 cycles, indicating that the catalyst has good stability.

[0077] Example 2

[0078] A preparation method of a platinum-lead alloy catalyst for photocatalytic dehydrogenation of propane to propylene. The preparation method is the same as that in Example 1, except that: in step 7), the temperature after heating is 300 °C, and the other conditions remain unchanged. A platinum-lead alloy catalyst is prepared and denoted as PtPb / ZnO-300.

[0079] Example 3

[0080] A preparation method of a platinum-lead alloy catalyst for photocatalytic dehydrogenation of propane to propylene. The preparation method is the same as that in Example 1, except that: in step 7), the temperature after heating is 400 °C, and the other conditions remain unchanged. A platinum-lead alloy catalyst is prepared and denoted as PtPb / ZnO-400.

[0081] The catalytic performances of the platinum-lead alloy catalysts prepared in the above Example 2 and Example 3 are shown in Table 2 below.

[0082] Table 2 Photocatalytic performance table of PtPb / ZnO-300 and PtPb / ZnO-400

[0083]

[0084] Comparative Examples 1-6

[0085] To examine the influence of lead on the performance of the platinum-lead alloy catalyst, the preparation method is the same as that in Example 1, except that: for Comparative Example 1, lead nitrate in step 1) is removed and denoted as Pt / ZnO; for Comparative Example 2, lead nitrate in step 1) is replaced with stannous chloride dihydrate and denoted as PtSn / ZnO; for Comparative Example 3, lead nitrate in step 1) is replaced with ferric nitrate nonahydrate and denoted as PtFe / ZnO; for Comparative Example 4, lead nitrate in step 1) is replaced with cobalt nitrate hexahydrate, and the pH control in step 2) is changed from 8.5 to 9.1 and denoted as PtCo / ZnO; for Comparative Example 5, lead nitrate in step 1) is replaced with nickel nitrate hexahydrate, and the pH control in step 2) is changed from 8.5 to 9.1 and denoted as PtNi / ZnO; for Comparative Example 6, lead nitrate in step 1) is replaced with copper nitrate trihydrate and denoted as PtCu / ZnO. The obtained products are used for photocatalytic dehydrogenation of propane to propylene, and the reaction steps are the same as those in Example 1. The results are shown in Table 3.

[0086] Table 3 Photocatalytic performance table of the catalysts obtained in Example 1 and Comparative Examples 1-6

[0087]

[0088]

[0089] The results show that lead has a significant impact on the performance of the platinum-lead alloy catalyst. The photocatalytic activity of the platinum-lead alloy catalyst obtained in Example 1 for the dehydrogenation of propane to produce propylene is superior to that of the catalyst without lead obtained in Comparative Example 1, and is also superior to the catalysts obtained in Comparative Examples 2-6 in which lead is replaced by other metals.

[0090] Comparative Example 7

[0091] To examine the effect of platinum on the performance of the platinum-lead alloy catalyst, the preparation method was the same as that in Example 1, except that chloroplatinic acid hexahydrate in step 5) was removed, denoted as Pb / ZnO. The obtained product was used for the photocatalytic dehydrogenation of propane to produce propylene, and the reaction steps were the same as those in Example 1. The results are shown in Table 4.

[0092] Table 4 Photocatalytic performance of the catalysts obtained in Example 1, Comparative Example 1 and Comparative Example 7

[0093]

[0094] The results show that lead in the platinum-lead alloy catalyst is a catalyst promoter for platinum. Lead itself has almost no photocatalytic activity for the dehydrogenation of propane to produce propylene. The catalyst without platinum obtained in Comparative Example 7 has much lower photocatalytic activity and propylene selectivity for the dehydrogenation of propane to produce propylene than the platinum-lead alloy catalyst obtained in Example 1.

[0095] Comparative Examples 8-10

[0096] To examine the effect of lead content on the catalyst performance, the preparation method was the same as that in Example 1, except that 0.04 mmol of lead nitrate in step 1) was replaced by 0.02 mmol, 0.08 mmol or 0.33 mmol of lead nitrate. The obtained product was used for the photocatalytic dehydrogenation of propane to produce propylene, and the reaction steps were the same as those in Example 1. The results are shown in Table 5.

[0097] Table 5 Catalytic performance of catalysts with different lead contents

[0098]

[0099] The results show that as the amount of lead nitrate added increases, the photocatalytic activity of the catalyst for the dehydrogenation of propane to produce propylene first increases and then decreases. The platinum-lead alloy catalyst obtained in Example 1 has the highest photocatalytic activity for the dehydrogenation of propane to produce propylene among the catalysts with different lead contents.

[0100] Comparative Examples 11-12

[0101] To examine the effect of the carrier type on the catalyst performance, that is, the preparation method was the same as that in Example 1, except that:

[0102] For Comparative Example 11, zinc nitrate hexahydrate in step 1) was replaced with aluminum nitrate nonahydrate;

[0103] For Comparative Example 12, zinc nitrate hexahydrate in step 1) was replaced with cerium nitrate hexahydrate.

[0104] The obtained product was used for photocatalytic propane dehydrogenation to prepare propylene, and the reaction steps were the same as those in Example 1. The results are shown in Table 6.

[0105] Table 6 Photocatalytic performance of catalysts with different supports

[0106]

[0107] The results show that the photocatalytic activity and propylene selectivity of the platinum-lead alloy catalyst using zinc oxide as the support for propane dehydrogenation to prepare propylene are superior to those of other supports.

[0108] Obviously, the above-mentioned embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limiting the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to enumerate all the implementation manners here. Any obvious changes or modifications derived from the technical solutions of the present invention still fall within the protection scope of the present invention.

Claims

1. A platinum-lead alloy catalyst, characterized in that, The chemical formula of the platinum-lead alloy catalyst is PtPb / ZnO. In the structure of the platinum-lead alloy catalyst, the active substance platinum-lead alloy is dispersed on the surface of the carrier zinc oxide.

2. The platinum-lead alloy catalyst according to claim 1, wherein The mass ratio of the platinum-lead alloy to zinc oxide is 1-2%.

3. The preparation method of the platinum-lead alloy catalyst according to any one of claims 1-2, characterized in that, It includes the following steps: Dissolve zinc salt and lead salt in deionized water to obtain solution A; Dissolve sodium carbonate in deionized water to obtain solution B; Dropwise mix solution A and solution B while controlling the pH to be 8.0-8.5 to obtain a crude product; Wash and freeze-dry the crude product to obtain a precursor material; In an air atmosphere, heat up the precursor material and maintain it at this temperature, and then cool it down to room temperature to obtain lead-modified zinc oxide; Uniformly disperse the lead-modified zinc oxide and chloroplatinic acid hexahydrate in deionized water and stir to obtain an impregnated crude product; Centrifuge and dry the impregnated crude product to obtain a platinum-impregnated product; In a hydrogen-argon mixed atmosphere, heat up the platinum-impregnated product and then cool it down to room temperature to obtain the platinum-lead alloy catalyst.

4. The preparation method according to claim 3, characterized in that, During the preparation of lead-modified zinc oxide, the conditions for heating the precursor material and maintaining the temperature are as follows: heating at a rate of 5-6 °C·min -1 to 400-410 °C and maintaining at this temperature for 2-2.5 h.

5. The preparation method according to claim 3, wherein, The conditions for heating the platinum-impregnated product are as follows: heating at a rate of 5 - 6 °C·min -1 to 300 - 500 °C and maintaining at this temperature for 2 - 2.5 h; and / or In the hydrogen-argon mixed atmosphere, the volume ratio of hydrogen to argon is 1:(9-10).

6. The preparation method according to claim 3, characterized in that, In the solution A, the concentration of the zinc salt is 1.2 to 1.6 mol·L -1 , and the concentration of the lead salt is 2.6 to 3.0 mmol·L -1 ; and / or The zinc salt is selected from zinc nitrate, and the lead salt is selected from lead nitrate; and / or In the solution B, the concentration of sodium carbonate is 0.6 to 1.0 mol·L -1 ; and / or The volume ratio of solution A to solution B is (15-16):(45-55).

7. The preparation method according to claim 3, characterized in that, The molar ratio of zinc, lead in the lead-modified zinc oxide to chloroplatinic acid hexahydrate is (18-24):(0.039-0.045):(0.078-0.090).

8. The application of the platinum-lead alloy catalyst according to claim 1 or 2 in the photocatalytic dehydrogenation of propane to prepare propylene.

9. The application according to claim 8, wherein The application includes the following steps: Under the protection of an inert gas, introduce propane into a closed reaction kettle with a light-transmitting quartz glass window added with a platinum-lead alloy catalyst and carry out the reaction under light irradiation conditions.

10. The application according to claim 9, characterized in that, The volume ratio of propane to the inert gas is 5:95; and / or The inert gas is argon; and / or The gas pressure in the reaction kettle is 0.1-0.121 MPa; and / or The light source for the light irradiation is ultraviolet light, preferably ultraviolet light of 365 nm.

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