Gold / gold palladium supported zinc-magnesium solid solution catalysts, their preparation methods, and their application in photocatalytic methane production of C2 hydrocarbons.

Abstract

This invention provides a gold / gold palladium supported zinc-magnesium solid solution catalyst, its preparation method, and its application in photocatalytic methane conversion to C2 hydrocarbons. It relates to the field of photocatalytic methane conversion technology. The catalyst preparation steps are simple and time-saving. Deionized water is mostly used as a solvent in the preparation process, resulting in less pollution. The equipment requirements are not high, and the reaction conditions are easy to achieve. The photocatalytic methane reaction is a gas-solid reaction with mild conditions, and the products are easily separated from the catalyst after the reaction.

Description

Technical Field

[0001] This invention belongs to the technical field of photocatalytic methane conversion, specifically relating to a gold-palladium supported zinc-magnesium solid solution catalyst, its preparation method, and its application in the photocatalytic production of C2 hydrocarbons from methane. Background Technology

[0002] As a major component of natural gas, shale gas, and methane hydrate, methane (CH4) is not only inexpensive and abundant, but it can also serve as a basic chemical feedstock for the synthesis of other value-added chemicals. However, due to methane's inert nature—its symmetrical tetrahedral geometry, low polarizability, and high CH bond energy—traditional methane conversion requires harsh reaction conditions and / or strong oxidants, and is energy-intensive, resulting in excessive carbon dioxide emissions. Under these harsh conditions, catalysts often accumulate rapidly and sinter, leading to catalyst deactivation.

[0003] In recent years, photocatalysis has attracted increasing attention in the field of methane conversion due to its ability to activate the CH bond in methane at room temperature. In 2023, Zhang Tierui et al. used zinc oxide (M / ZnO) supported by different transition metals as catalysts, which exhibited distinctly different selectivities for the photocatalytic oxidative coupling of C2-C4 hydrocarbons into methane. The study showed that photocatalysis on ZnO produces O2. – The active sites can efficiently activate methane to generate adsorbed ·CH3. When ·CH3 is on the surface of metal Au or Ag, it will selectively couple to generate C2H6, but on the surface of metals such as Ni, Ru, and Pt, ·CH3 is over-oxidized to CO2. Therefore, in the prior art, ethane selectivity is low and the degree of product dehydrogenation is low. Summary of the Invention

[0004] In view of this, the present invention provides a gold / gold palladium supported zinc-magnesium solid solution catalyst.

[0005] It is also necessary to provide a method for preparing a gold / gold palladium supported zinc-magnesium solid solution catalyst.

[0006] It is also necessary to provide an application of a gold / gold palladium supported zinc-magnesium solid solution catalyst for the photocatalytic production of C2 hydrocarbons from methane.

[0007] The technical solution adopted by this invention to solve its technical problem is:

[0008] A gold / gold palladium supported zinc-magnesium solid solution catalyst was first synthesized by precipitation method to obtain highly crystalline Zn. m Mg n O, and then use the NaBH4 reduction method to load gold or gold-palladium nanoparticles onto Zn. m Mg n The gold / gold palladium supported zinc-magnesium solid solution catalyst was prepared on O;

[0009] The general formula is: Au x Pd y / Zn m Mg n O

[0010] Among them: 0 <x≤5,0≤y≤3,0<m≤0.99,n=1-m。

[0011] The preparation method of the gold / gold palladium supported zinc-magnesium solid solution catalyst as described above includes the following steps:

[0012] S1: Under alkaline conditions, zinc magnesium salt solution is added to ethyl acetate and stirred to produce a white precipitate solid;

[0013] S2: The white precipitate solid was washed and centrifuged multiple times, and then dried to obtain zinc magnesium oxide powder;

[0014] S3: Grind and calcine zinc-magnesium oxide powder to obtain zinc-magnesium solid solution;

[0015] S4: The zinc-magnesium solid solution is placed in the precursor solution for a first predetermined time for loading, then a reducing agent is added for reduction, and the solution is allowed to stand, centrifuged, and dried to obtain a gold / gold-palladium supported zinc-magnesium solid solution catalyst.

[0016] Preferably, in step S1, the zinc-magnesium salt solution is specifically formed by dissolving zinc acetate and magnesium acetate in anhydrous ethanol.

[0017] Preferably, in step S1, the alkaline conditions are adjusted using potassium hydroxide.

[0018] Preferably, in step S3, the zinc magnesium oxide powder is calcined at a temperature of 200°C to 420°C.

[0019] Preferably, in step S4, the precursor solution includes a chloroauric acid solution.

[0020] Preferably, in step S4, the precursor solution includes: chloroauric acid solution and palladium chloride solution.

[0021] Preferably, the first predetermined time is 20 minutes or more, the reducing agent is NaBH4, and the reduction time is 1 hour to 3 hours.

[0022] The application of the gold / gold palladium supported zinc-magnesium solid solution catalyst for photocatalytic methane to C2 hydrocarbons as described above, using the above-mentioned gold / gold palladium supported zinc-magnesium solid solution catalyst for photocatalytic oxidative coupling of methane to C2 hydrocarbons.

[0023] Preferably, the light source for photocatalysis is ultraviolet light, and the wavelength of the ultraviolet light is 300nm to 2500nm.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] This invention provides a metal-loaded Au x Pd y / Zn m Mg n O solid solution is used as a photocatalyst. The preparation steps are simple and the time is short. Deionized water is mostly used as a solvent in the preparation process, resulting in less pollution. The equipment requirements are not high and the reaction conditions are easy to achieve.

[0026] Metal-loaded Au x Pd y / Zn m Mg n O-solid solution, used as a photocatalyst with methane as the sole feedstock, efficiently catalyzes the reaction. Photogenerated holes on the catalyst surface oxidize methane to methyl radicals, which then dimerize on the surface or in the gas phase to form ethane. Ethane undergoes dehydrogenation to further generate ethylene, and proton hydrogen is reduced by photogenerated electrons on the metal to produce hydrogen gas. (The text then repeats the last sentence about Au, which seems unrelated and likely refers to a different process.) x Pd y / Zn m Mg n O solid solution acts as a photocatalyst, possessing suitable redox potential and surface structure, which facilitates the formation of intermediate species and prevents further dehydrogenation of ethane, enabling efficient methane coupling to produce ethane and hydrogen. On one hand, the photocatalyst-catalyzed methane reaction is a gas-solid reaction under mild conditions, and the products are easily separated from the catalyst after the reaction. On the other hand, Au... x Pd y / Zn m Mg n O solid solution, as a photocatalyst, possesses a suitable redox potential, which controls the degree of dehydrogenation of methane, avoids over-oxidation, and improves product selectivity and yield. Attached Figure Description

[0027] Figure 1 XRD patterns of zinc oxide and zinc-magnesium solid solutions prepared in Examples 1 to 3.

[0028] Figure 2 Au prepared in Example 4 0.25 / Zn 0.95 Mg 0.05 XRD pattern of O.

[0029] Figure 3 Zn with different gold contents as shown in Examples 4 to 9 0.95 Mg 0.05 O photocatalytic methane oxidative coupling performance diagram.

[0030] Figure 4 Au3 / Zn in Example 80.95 Mg 0.05 O photocatalytic performance cycle diagram.

[0031] Figure 5 Au3Pd prepared in Example 10 0.3 / Zn 0.95 Mg 0.05 XRD pattern of O.

[0032] Figure 6 Examples 10 to 15 show Zn with different palladium contents while maintaining the same gold content. 0.95 Mg 0.05 O photocatalytic methane oxidative coupling performance diagram.

[0033] Figure 7 Au3Pd1 / Zn in Example 13 0.95 Mg 0.05 O photocatalytic performance cycle diagram.

[0034] Figure 8 Zn with different gold-palladium ((1.0%–3.0 wt%) Au-(1.0%–3.0 wt%) Pd) contents 0.95 Mg 0.05 O photocatalytic methane oxidative coupling performance diagram. Detailed Implementation

[0035] The technical solutions and effects of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0036] A gold / gold palladium supported zinc-magnesium solid solution catalyst was first synthesized by precipitation method to obtain highly crystalline Zn. m Mg n O, and then use the NaBH4 reduction method to load gold or gold-palladium nanoparticles onto Zn. m Mg n The gold / gold-palladium supported zinc-magnesium solid solution catalyst was prepared on O, wherein the loading amount of gold or gold-palladium nanoparticles was: 0 <Au≤5Wt%,0≤Pd≤3Wt%;

[0037] The general formula is: Au x Pd y / Zn m Mg n O

[0038] Among them: 0 <x≤5,0≤y≤3,0<m≤0.99,n=1-m。

[0039] Specifically, Au x Pd y / Zn m Mg nO solid solution, as a photocatalyst, possesses a suitable redox potential, which controls the degree of dehydrogenation of methane, avoids over-oxidation, and improves product selectivity and yield.

[0040] The preparation method of the gold / gold palladium supported zinc-magnesium solid solution catalyst as described above includes the following steps:

[0041] S1: Under alkaline conditions, zinc magnesium salt solution is added to ethyl acetate and stirred to produce a white precipitate solid;

[0042] S2: The white precipitate solid was washed and centrifuged multiple times, and then dried to obtain zinc magnesium oxide powder;

[0043] S3: Grind and calcine zinc-magnesium oxide powder to obtain zinc-magnesium solid solution;

[0044] S4: The zinc-magnesium solid solution is placed in the precursor solution for a first predetermined time for loading, then a reducing agent is added for reduction, and the solution is allowed to stand, centrifuged, and dried to obtain a gold / gold-palladium supported zinc-magnesium solid solution catalyst.

[0045] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0046] This invention provides a metal-loaded Au x Pd y / Zn m Mg n O solid solution is used as a photocatalyst. The preparation steps are simple and the time is short. Deionized water is mostly used as a solvent in the preparation process, resulting in less pollution. The equipment requirements are not high and the reaction conditions are easy to achieve.

[0047] Furthermore, in step S1, the zinc-magnesium salt solution is specifically formed by dissolving zinc acetate and magnesium acetate in anhydrous ethanol.

[0048] Furthermore, in step S1, the alkaline conditions are adjusted using potassium hydroxide.

[0049] Furthermore, in step S1, stirring for 1.5h to 2.5h generates a white precipitate.

[0050] Furthermore, in step S2, the product is washed with ethanol and centrifuged 3 to 10 times to remove excess alkali metal ions.

[0051] Furthermore, in step S2, the drying temperature is 60℃~100℃.

[0052] Furthermore, in step S3, the temperature is increased to 200°C to 420°C at a rate of 1°C to 5°C per minute, and calcined for 0.5h to 2h.

[0053] Furthermore, in step S4, the precursor solution includes: a chloroauric acid solution with a gold ion concentration of 2 mg / mL to 4 mg / mL, and a gold content of 0.25% to 5.0% (referring to 0.1 g of zinc-magnesium solid solution with a gold loading content of 0.25% to 5.0%) based on the mass of the zinc-magnesium solid solution carrier.

[0054] Further, in step S4, the precursor solution comprises: a chloroauric acid solution and a palladium chloride solution, with a gold ion concentration of 2 mg / mL to 4 mg / mL and a palladium ion concentration of 0 mg / mL to 2 mg / mL. Based on the mass of the zinc-magnesium solid solution support, the gold content is 0.25% to 5.0% by mass. The palladium content is 0.3% to 3.0% by mass (referring to 0.1 g of zinc-magnesium solid solution, where the gold content is 0.25% to 5.0% by mass and the palladium content is 0.3% to 3.0% by mass).

[0055] Furthermore, the first predetermined time is more than 20 minutes, the reducing agent is NaBH4, the reduction time is 1h to 3h, and sodium borohydride is chemically reduced to form gold single atoms / single atom clusters.

[0056] The application of the gold / gold palladium supported zinc-magnesium solid solution catalyst for photocatalytic methane to C2 hydrocarbons as described above, using the above-mentioned gold / gold palladium supported zinc-magnesium solid solution catalyst for photocatalytic oxidative coupling of methane to C2 hydrocarbons.

[0057] Specifically, using a batch reactor, a gold / gold palladium supported zinc-magnesium solid solution catalyst is dispersed or attached in a quartz tank and placed inside a reaction vessel. The atmosphere inside the reaction vessel is fully replaced with an inert gas, methane gas is introduced and oxygen is injected, and the reaction is carried out under light for more than 1 hour to prepare C2 hydrocarbons.

[0058] Furthermore, the light source for photocatalysis is ultraviolet light, and the wavelength of the ultraviolet light is 300nm to 2500nm.

[0059] Specifically, metal-loaded Au x Pd y / Zn m Mg n O-solid solution, used as a photocatalyst with methane as the sole feedstock, efficiently catalyzes the reaction. Photogenerated holes on the catalyst surface oxidize methane to methyl radicals, which then dimerize on the surface or in the gas phase to form ethane. Ethane undergoes dehydrogenation to further generate ethylene, and proton hydrogen is reduced by photogenerated electrons on the metal to produce hydrogen gas. (The text then repeats the last sentence about Au, which seems unrelated and likely refers to a different process.) x Pd y / Zn m Mg nThe O solid solution serves as a photocatalyst, possessing suitable redox potentials and surface structures that facilitate the formation of intermediate species and prevent further dehydrogenation of ethane, enabling efficient methane coupling to produce ethane and hydrogen. Furthermore, the photocatalyst-catalyzed methane reaction is a gas-solid reaction under mild conditions, and the products are easily separated from the catalyst. Additionally, the gold-supported Zn... 0.95 Mg 0.05 High selectivity and high yield of ethane can be obtained on O solid solution catalysts, and Zn supported on gold and palladium catalysts can also achieve this. 0.95 Mg 0.05 High selectivity and high yield of ethylene can be obtained on O solid solution catalysts. The catalysts are simple to prepare and can be recycled multiple times.

[0060] Example 1:

[0061] S1: Add 100 mL of anhydrous ethanol to a beaker, place the beaker in an ultrasonic machine, weigh 2.0853 g of Zn(OAc)₂·2H₂O, slowly add it to the anhydrous ethanol and sonicate to dissolve. Then add 0.1072 g of Mg(OAc)₂·4H₂O to the Zn(OAc)₂·2H₂O solution and sonicate for 40 min to dissolve. A zinc-magnesium salt solution is obtained. Weigh 1.6833 g of KOH and dissolve it in a beaker containing 10 mL of anhydrous ethanol, sonicating for 40 min. Then, slowly add the prepared potassium hydroxide solution to the zinc-magnesium salt solution while stirring at 200 r / min for 2 h to form a white precipitate. Finally, add 5 mL of ethyl acetate and stir for a period of time.

[0062] S2: The white precipitate obtained in step S1 was washed with ethanol and centrifuged 6 times. After washing, it was dried at 80°C to obtain zinc magnesium oxide powder.

[0063] S3: Grind the zinc-magnesium oxide powder, then place the ground powder into a muffle furnace for calcination. The temperature is increased to 420℃ at a rate of 5℃ / min and calcined for 2 hours to obtain the zinc-magnesium solid solution Zn. 0.95 Mg 0.05 O.

[0064] S4: Prepare a chloroauric acid solution with a gold ion concentration of 4 mg / mL using deionized water as the solvent. Weigh 0.1 g of Zn. 0.95 Mg 0.05 A zinc-magnesium solid solution was added to 50 mL of deionized water and ultrasonically dispersed for 30 min. After ultrasonication, 131 μL of chloroauric acid tetrahydrate (4 mg / mL) was transferred and stirred for another 30 min. Then, 10 mL (5 mg / mL) of NaBH4 solution was slowly added dropwise to the above solution, and the mixture was stirred at 150 rpm for 3 h. After standing, centrifugation and drying were performed to collect the sample, yielding Au. 0.25 / Zn 0.95 Mg 0.05O sample.

[0065] Example 2:

[0066] In step S1: Weigh 1.9756g Zn(OAc)2·2H2O and 0.2145g Mg(OAc)2·4H2O; the other steps are the same as in Example 1, to obtain zinc-magnesium solid solution Zn. 0.9 Mg 0.1 O.

[0067] Example 3:

[0068] In step S1: Weigh 1.7561g Zn(OAc)2·2H2O and 0.4289g Mg(OAc)2·4H2O; the other steps are the same as in Example 1, to obtain zinc-magnesium solid solution Zn. 0.8 Mg 0.2 O.

[0069] The three zinc-magnesium solid solutions obtained in Examples 1 to 3 and their oxidizing properties were tested by X-ray diffraction. XRD patterns of zinc oxide and the three zinc-magnesium solid solutions were obtained, as shown below. Figure 1 As shown.

[0070] Depend on Figure 1 It can be seen that the pure XRD peaks of ZnO exhibit typical wurtzite phase, and Zn 0.95 Mg 0.05 O, Zn 0.9 Mg 0.1 O and Zn 0.8 Mg 0.2 O and the peak positions are all comparable to Figure 1 The peak positions in b correspond one-to-one, indicating the successful synthesis of a zinc-magnesium solid solution with the corresponding crystal structure to zinc oxide. Furthermore, with the increase of Zn... m Mg n As the amount of Mg added to the ZnO solid solution gradually increases, the XRD peak intensity of the sample gradually decreases, indicating that the particle size of the sample decreases with increasing Mg addition. Notably, with increasing Mg addition, only the (002) plane of the crystal shifts to a higher angle. Excessive Mg content can lead to excessive oxidation of methane to CO2, reducing C2 selectivity, which can be determined in the subsequent activity test. This demonstrates that the (002) plane of ZnO is affected by the Mg element in the solid solution.

[0071] Example 4

[0072] S4: Using deionized water as solvent, prepare a chloroauric acid solution with a gold ion concentration of 4 mg / mL. Weigh out the Zn obtained in Example 1. 0.95 Mg 0.050.1 g of zinc magnesium solid solution was added to 50 mL of deionized water and ultrasonically dispersed for 30 min. After ultrasonication, 131 μL of chloroauric acid tetrahydrate (4 mg / mL) was transferred and stirred for another 30 min. Then, 10 mL (5 mg / mL) of NaBH4 solution was slowly added dropwise to the above solution, and the mixture was stirred at 150 r / min for 3 h. After standing, centrifugation and drying were performed to collect the sample, yielding Au. 0.25 / Zn 0.95 Mg 0.05 Sample O, based on the mass of the zinc-magnesium solid solution photocatalyst, has a gold mass percentage of 0.25%.

[0073] By measuring XRD, such as Figure 2 As shown, Au is obtained. 0.25 / Zn 0.95 Mg 0.05 O sample, where Au loading was too low to be detected.

[0074] S5: Take 5mg of Au prepared from 0.25 / Zn 0.95 Mg 0.05 The O catalyst was dispersed in 2 ml of ultrapure water, and the dispersed liquid was evenly dropped onto a 4 cm quartz trough. After drying at 60 °C, the quartz trough was placed in a 150 ml batch reactor. Inert gas was introduced to remove air from the reactor, followed by the introduction of high-purity methane gas to replace the atmosphere with methane. The inlet and outlet ports were then closed. 2 mL of O2 was injected, and the mixture was stirred for 1 h for adsorption. A 300 W Xe lamp was turned on at a wavelength of 300 nm, and the reaction was allowed to proceed for 3 h. The resulting gas was connected to a gas chromatograph via a six-way valve.

[0075] By combining the standard curves obtained from ethane and ethylene in gas chromatography, the conversion rate of C2 and the selectivity for C2 formation can be calculated. The selectivity for C2 can be calculated using the following formula:

[0076] Selectivity: Sel(%) = [(2n(C2H6) + 2n(C2H4))] / [(2n(C2H6) + 2n(C2H4)) + n(CO2) + n(CO)] x 100% (n is the yield of each product)

[0077] Examples 5-9:

[0078] Other conditions are the same as in Example 4, and the variables are shown in Table 1:

[0079] Table 1

[0080]

[0081] The conversion rate and selectivity of C2 obtained from the reactions in Examples 4 to 9 are as follows: Figure 3As shown, by Figure 3 Zn with different gold contents 0.95 Mg 0.05 In the photocatalytic methane oxidative coupling performance graph, we observed a volcanic-like trend in the relationship between Au content and ethane yield. The graph shows that as Au content increases, both ethane yield and C2 product selectivity increase. The Au3 / Zn ratio also shows a significant increase. 0.95 Mg 0.05 O has higher ethane yield and better C2 product selectivity.

[0082] The Au3 / Zn obtained in Example 8 0.95 Mg 0.05 O Perform the cycle test 6 times as shown in step S5, with a 3-hour interval between each cycle test. The test results are as follows: Figure 4 As shown.

[0083] Depend on Figure 4 It can be seen that Au3 / Zn 0.95 Mg 0.05 O-cycle performance is good.

[0084] Example 10:

[0085] Using deionized water as a solvent, prepare a chloroauric acid solution with a gold ion concentration of 4 mg / mL and a palladium chloride solution with a palladium ion concentration of 2 mg / mL.

[0086] Weigh the Zn obtained in Example 1 0.95 Mg 0.05 0.1 g of zinc magnesium solid solution was added to 100 ml of deionized water and ultrasonically dispersed for 10 min. After ultrasonication, 1568 μL of chloroauric acid tetrahydrate (4 mg / mL) and 250 μL of palladium chloride (2 mg / mL) were transferred and stirred for 2 h. Under ice-water bath conditions, 10 mL (5 mg / mL) of NaBH4 solution was slowly added dropwise to the above solution and stirred at 150 r / min for 1 h. After standing, centrifugation and drying were performed to collect the sample, yielding Au3Pd. 0.3 / Zn 0.95 Mg 0.05 Sample O, based on the mass of the zinc-magnesium solid solution photocatalyst, has a gold content of 3% and a palladium content of 0.3%.

[0087] By measuring XRD, such as Figure 5 As shown, Au3Pd was obtained. 0.3 / Zn 0.95 Mg 0.05 For sample O, an Au peak appears in the graph, which corresponds to the Au standard card JCPDS 04-0874. The inability to detect Pd is due to the low loading.

[0088] S5: Take 5 mg of the prepared Au3Pd 0.3 / Zn 0.95 Mg 0.05 The O catalyst was dispersed in 2 ml of ultrapure water, and the dispersed liquid was evenly dropped onto a 4 cm quartz trough. After drying at 60 °C, the quartz trough was placed in a 150 ml batch reactor. Inert gas was introduced to remove air from the reactor, followed by the introduction of high-purity methane gas to replace the atmosphere with methane. The inlet and outlet ports were then closed. 2 mL of O2 was injected, and the mixture was stirred for 1 h for adsorption. A 300 W Xe lamp was turned on at a wavelength of 300 nm, and the reaction was allowed to proceed for 3 h. The resulting gas was connected to a gas chromatograph via a six-way valve.

[0089] By combining the standard curves obtained from ethane and ethylene in gas chromatography, the conversion rate of C2 and the selectivity for C2 formation can be calculated. The selectivity for C2 can be calculated using the following formula:

[0090] Selectivity: Sel(%) = [(2n(C2H6) + 2n(C2H4))] / [(2n(C2H6) + 2n(C2H4)) + n(CO2) + n(CO)] x 100% (n is the yield of each product)

[0091] Examples 11-15:

[0092] Other conditions are the same as in Example 10, and the variables are shown in Table 2:

[0093] Table 2

[0094]

[0095]

[0096] The conversion rate and selectivity of C2 obtained from the reactions in Examples 10 to 15 are as follows: Figure 6 As shown, Figure 6 Zn with a content of 3 Wt% Au-(0.3%~3.0 Wt%) Pd 0.95 Mg 0.05 The photocatalytic performance of methane oxidative coupling (MCO) is shown in the graph. Introducing Pd into the Au lattice improves the photocatalytic performance, particularly significantly enhancing ethylene selectivity. We observed a volcanic-like trend in the relationship between Pd content and ethylene yield. The graph shows that as Pd content increases, the ethylene yield decreases, but the highest yield and best C2 product selectivity (approximately 80%) are observed in the 3Wt%Au + 1Wt%Pd + ethylene combination.

[0097] The Au3Pd1 / Zn obtained in Example 13 0.95 Mg 0.05O Perform the cycle test as shown in step S5 four times, with a 3-hour interval between each cycle test. The test results are as follows: Figure 7 As shown.

[0098] Depend on Figure 7 It can be seen that Au3Pd1 / Zn 0.95 Mg 0.05 O-cycle performance is good.

[0099] Examples 16-18:

[0100] Other conditions are the same as in Example 10, and the variables are shown in Table 3:

[0101] Table 3

[0102]

[0103] Comparative Example 1:

[0104] S5: Take the Zn obtained in Example 1 0.95 Mg 0.05 5 mg of O2 was dispersed in 2 ml of ultrapure water, and the dispersed liquid was evenly dropped onto a 4 cm quartz trough. After drying at 60 °C, the quartz trough was placed in a 150 ml batch reactor. Inert gas was introduced to remove air from the reactor, followed by the introduction of high-purity methane gas to replace the atmosphere with methane. The inlet and outlet ports were then closed. 2 mL of O2 was injected, and the mixture was stirred for 1 h for adsorption. A 300 W Xe lamp was turned on at a wavelength of 300 nm, and the reaction was allowed to proceed for 3 h. The gas produced after the reaction was connected to a gas chromatograph via a six-way valve.

[0105] The conversion rate and selectivity of C2 obtained from the reactions of Comparative Example 1, Example 10, Example 16, Example 17, Example 18, and Example 13 are as follows: Figure 8 As shown, Figure 8 Zn with a content of (1.0%–3.0 wt%) Au and (1.0%–3.0 wt%) Pd 0.95 Mg 0.05 The graph shows the photocatalytic coupling performance of methane oxidation in Au3Pd1 / Zn. 0.95 Mg 0.05 The highest ethylene yield was observed at O, with the best C2 product selectivity, approximately 80%, compared to... Figure 6 The results are cross-referenced.

[0106] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the invention. Those skilled in the art will understand that implementing all or part of the above-described embodiments and making equivalent changes in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A gold / gold-palladium supported zinc-magnesium solid solution catalyst, characterized in that, First, highly crystalline Zn is synthesized using a precipitation method. m Mg n O, and then use the NaBH4 reduction method to load gold or gold-palladium nanoparticles onto Zn. m Mg n The gold / gold palladium supported zinc-magnesium solid solution catalyst was prepared on O; The general formula is: Au x Pd y / Zn 0.95 Mg 0.05 O or Au x Pd y / Zn 0.9 Mg 0.1 O or Au x Pd y / Zn 0.8 Mg 0.2 O; Among them: 0 <x≤5,0≤y≤3。 2. The method for preparing the gold / gold-palladium supported zinc-magnesium solid solution catalyst as described in claim 1, characterized in that, Includes the following steps: S1: Under alkaline conditions, zinc magnesium salt solution is added to ethyl acetate and stirred to produce a white precipitate solid; S2: The white precipitate solid was washed and centrifuged multiple times, and then dried to obtain zinc magnesium oxide powder; S3: Grind and calcine zinc-magnesium oxide powder to obtain zinc-magnesium solid solution; S4: The zinc-magnesium solid solution is impregnated in the precursor solution for a first predetermined time for loading, then a reducing agent is added for reduction, and the mixture is allowed to stand, centrifuged, and dried to obtain a gold / gold-palladium supported zinc-magnesium solid solution catalyst.

3. The method for preparing the gold / gold-palladium supported zinc-magnesium solid solution catalyst as described in claim 2, characterized in that, In step S1, the zinc-magnesium salt solution is specifically prepared by dissolving zinc acetate and magnesium acetate in anhydrous ethanol to form a zinc-magnesium salt solution.

4. The method for preparing the gold / gold-palladium supported zinc-magnesium solid solution catalyst as described in claim 2, characterized in that, In step S1, the alkaline conditions are adjusted using potassium hydroxide.

5. The method for preparing the gold / gold-palladium supported zinc-magnesium solid solution catalyst as described in claim 2, characterized in that, In step S3, the zinc-magnesium oxide powder is calcined at a temperature of 200℃~420℃.

6. The method for preparing the gold / gold palladium supported zinc-magnesium solid solution catalyst as described in claim 5, characterized in that: In step S4, the precursor solution includes a chloroauric acid solution.

7. The method for preparing the gold / gold palladium supported zinc-magnesium solid solution catalyst as described in claim 5, characterized in that: In step S4, the precursor solution includes: chloroauric acid solution and palladium chloride solution.

8. The method for preparing the gold / gold palladium supported zinc-magnesium solid solution catalyst as described in claim 5, characterized in that: The first predetermined time is more than 20 minutes, the reducing agent is NaBH4, and the reduction time is 1 hour to 3 hours.

9. The application of the gold / gold palladium supported zinc-magnesium solid solution catalyst as described in claim 1 in the photocatalytic production of C2 hydrocarbons from methane, characterized in that: The photocatalytic oxidative coupling of methane to C2 hydrocarbons was prepared using the aforementioned gold / gold-palladium supported zinc-magnesium solid solution catalyst.

Images