A method for photocatalytic dehydrogenative coupling of methane

Abstract

The present invention relates to a method for photocatalytic dehydrogenative coupling of methane. This method uses methane as a reactant and directly prepares ethylene and hydrogen under the conditions of a metal-loaded strontium titanate semiconductor photocatalyst and light irradiation (wavelength 300 nm to 800 nm). The reaction conditions are as follows: The reaction is carried out in an autoclave reactor. The reaction pressure of methane is usually 0.1 to 1 MPa, and the reaction temperature is room temperature. The catalyst for this method is simple to prepare and highly efficient in catalyzing this reaction. This reaction is a gas-solid reaction, and the catalyst is easy to separate after the reaction. Strontium titanate is selected as the photocatalyst, which has a suitable redox potential, controls the dehydrogenation degree of methane, avoids over-oxidation, improves the product selectivity, and the selectivity of ethylene can reach 82%.

Description

Technical Field

[0001] The present invention relates to a method for preparing ethylene and hydrogen from methane, and particularly relates to the preparation of ethylene and hydrogen by photocatalytic methane dehydrogenation coupling reaction. Background Art

[0002] Ethylene is an important basic chemical raw material and is one of the chemical products with the largest production in the world. The ethylene industry is the core of the petrochemical industry. Ethylene products account for more than 75% of petrochemical products and play an important role in the national economy. Ethylene is widely used in the fields of synthesizing ethanol, synthetic fibers, synthetic rubbers, synthetic plastics, etc., and is also used to prepare vinyl chloride, acetaldehyde, styrene, ethylene oxide, explosives, etc. It is also used as an environmentally friendly ripening gas for fruits such as navel oranges, tangerines, and bananas. Currently, industrial ethylene is generally produced by high-temperature steam cracking of alkanes with more than C2 or light and heavy petroleum fractions. Petroleum is a non-renewable resource, and petroleum resources have been increasingly scarce in recent years. In 1982, G.E. Keller first proposed the process of catalytic coupling of methane to produce ethylene and ethane, which provided a new possibility for exploring a cheap ethylene raw material route. Due to the low price and relatively rich reserves of natural gas, using it as a raw material to produce ethylene and its downstream products has received more and more attention.

[0003] The technologies for producing ethylene from methane mainly include two routes: direct conversion and indirect conversion. Indirect conversion needs to first go through methane steam reforming to syngas, and then ethylene is produced from syngas through technologies such as methanol and MTO, or ethylene is produced from syngas through the Fischer-Tropsch synthesis process. The direct conversion method does not require intermediate products. Ethylene can be obtained in one step by oxidative coupling of methane under the action of a catalyst, or ethylene can also be obtained by dehydrogenation of methane under anaerobic conditions. In traditional thermal catalysis, the processes of methane oxidative coupling or dehydrogenation coupling usually require a relatively high temperature (usually greater than 700 °C), the reaction conditions are harsh, and high temperature poses great challenges to the reaction device and the stability of the catalyst.

[0004] In recent years, due to the characteristic of photocatalysis in activating the C-H bond of methane at room temperature, it has received more and more attention in the field of methane conversion. In 2021, Xiong Yujie et al. prepared a bimetal-modified zinc oxide photocatalyst (J. Am. Chem. Soc. 2021, 143, 1, 269–278). They found that zinc oxide loaded with AuPd alloy can be used as a photocatalyst to produce ethane and ethylene from methane, but ethylene is a minor product (selectivity less than 40%), and the hydrogen production is much less than the theoretical value.

[0005] There are problems in the prior art such as low ethylene selectivity, low dehydrogenation degree of products, and little hydrogen obtained. The existing technologies cannot directly prepare ethylene and hydrogen from methane efficiently. Therefore, developing a technical route for preparing ethylene and hydrogen with high efficiency under mild conditions has important application prospects. Summary of the Invention

[0006] The object of the present invention is to develop a method for directly dehydrogenating and coupling methane to simultaneously prepare ethylene and hydrogen, which has the characteristics of low reaction temperature, high selectivity of target products, and green and efficient reaction process. At the same time, the catalyst is simple to prepare and easy to separate and reuse.

[0007] The specific steps of the method for photocatalytic dehydrogenation and coupling of methane to prepare ethylene and hydrogen involved in the present invention are as follows:

[0008] Disperse or attach the metal-loaded strontium titanate catalyst on the conductive glass and place it in the reaction kettle. Fully displace the atmosphere in the reaction kettle with an inert gas, introduce methane gas to the specified pressure, irradiate with light, and the reaction time is not less than 1 hour. Ethylene and hydrogen are generated by the reaction. The loaded metal in the metal-loaded strontium titanate catalyst is one or more of palladium, platinum, rhodium, silver, gold, iridium, copper, and ruthenium, preferably one or more of palladium, gold, copper, and platinum.

[0009] The metal content (calculated by mass) in the metal-loaded strontium titanate catalyst is 0.1 wt% - 2 wt%, and preferably the metal loading amount (calculated by mass) is 0.3 wt% - 1.1 wt%.

[0010] The metal-loaded strontium titanate catalyst can be prepared by photodeposition method, atomic layer deposition method, impregnation method or ion sputtering method. The reaction pressure of the reaction substrate methane is 0.1 - 1 MPa, preferably 0.3 - 0.5 MPa. The wavelength range of the light source is 300 nm - 800 nm, preferably 400 nm. The dispersion concentration of the metal-loaded strontium titanate catalyst on the conductive glass is 0.1 mg·cm -2 ~2 mg·cm -2 , preferably 0.5 mg·cm -2 ~1 mg·cm -2 . The photoreaction time is 1 - 24 hours, preferably 3 - 6 hours. The particle size of the strontium titanate is 20 nm - 1000 nm, preferably 50 nm - 200 nm.

[0011] The invention uses a metal-loaded strontium titanate semiconductor as a photocatalyst and methane as the sole raw material to achieve the coupling of methane to ethylene and hydrogen production under room temperature light irradiation conditions. During the photoreaction process, methane is oxidized by the photogenerated holes on the surface of strontium titanate to methyl radicals. The methyl species combines with another methyl group, and then dehydrogenates to form ethylene. Proton hydrogen is reduced by the photogenerated electrons on the metal to generate hydrogen. Using strontium titanate as a photocatalyst, it has a suitable redox potential and surface structure, which is conducive to the formation of intermediate species and also prevents the further dehydrogenation of ethylene, and can achieve the efficient coupling of methane to produce ethylene and hydrogen. The reaction has the characteristics of high product selectivity, mild conditions, green and efficient, etc.

[0012] This method has a simple catalyst preparation and can efficiently catalyze this reaction. This reaction is a gas-solid reaction, and the catalyst is easily separated after the reaction. Strontium titanate is selected as the photocatalyst, which has a suitable redox potential, controls the dehydrogenation degree of methane, avoids over-oxidation, and improves the product selectivity. The selectivity of ethylene can reach 82%.

[0013] The beneficial effects achieved by the technical solution of the present invention compared with the prior art are as follows:

[0014] (1) No additional oxidant is required in this process. Only methane is used as the raw material to simultaneously produce ethylene and hydrogen, with a high atom utilization rate.

[0015] (2) No high temperature needs to be provided in this process. The reaction can occur at room temperature and relatively low pressure, with low requirements for the reaction equipment.

[0016] (3) This process is carried out in a batch reactor, and the reaction conditions are easy to control. The product collection and catalyst separation are simple.

[0017] (4) High selectivity and high yield of ethylene can be obtained on the palladium-loaded strontium titanate semiconductor catalyst in this process. The catalyst preparation is simple and can be recycled multiple times. Specific Embodiments

[0018] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention and do not limit the present invention.

[0019] The following gives specific embodiments

[0020] Example 1

[0021] Preparation of Pd-loaded strontium titanate catalyst (0.7wt% Pd / SrTiO3) by photodeposition method. Weigh 1.0 g of strontium titanate particles with a particle size of 50 nm, add them to 30 ml of methanol aqueous solution (methanol volume fraction is 10%), add chloropalladic acid according to the amount of palladium in the product with a mass percentage of 0.7%, stir evenly and transfer to a quartz autoclave. After purging with argon three times, under normal temperature and pressure, in an argon atmosphere, at a rotation speed of 300 r / min, irradiate with ultraviolet light at 365 nm for 1 h for photodeposition. Then wash with water three times and place in a vacuum drying oven at 60 °C for 12 h. Grind and collect to obtain strontium titanate particles loaded with metallic palladium with a particle size of 50 nm. Take 20 mg of the prepared strontium titanate particles loaded with metallic palladium with a particle size of 50 nm and disperse them in 2 ml of ultrapure water. The dispersed liquid is evenly dropped on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, place the conductive glass vertically in a 150 ml high-pressure autoclave. Pass in an inert gas to remove the air in the autoclave, then pass in high-purity methane gas to replace the atmosphere in the autoclave with a methane atmosphere. Then close the outlet, adjust the inlet pressure of methane, and adjust the methane pressure in the system to 0.3 MPa. Close the inlet. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 3 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. Analysis shows that the production rate of ethylene is 436 μmol·g -1 ·h -1 , the production rate of hydrogen is 723 μmol·g -1 ·h -1 , the conversion rate of methane is 1064 μmol·g -1 ·h -1 , and the selectivity of ethylene is 82% (two molecules of methane produce one molecule of ethylene).

[0022] Example 2

[0023] Preparation of Pd-loaded strontium titanate catalyst (0.1 wt% Pd / SrTiO3) by photodeposition method. Weigh 1.0 g of strontium titanate particles with a particle size of 50 nm, add them to 30 ml of methanol aqueous solution (methanol volume fraction is 10%), add chloropalladic acid in an amount corresponding to 0.7% of the mass percentage of palladium in the product, stir evenly and transfer to a quartz autoclave. After purging with argon three times, under normal temperature and pressure, in an argon atmosphere, at a rotation speed of 300 r / min, irradiate with ultraviolet light at 365 nm for 1 h for photodeposition. Then wash with water three times and place in a vacuum drying oven at 60 °C for 12 h. Grind and collect to obtain strontium titanate particles loaded with metallic palladium with a particle size of 50 nm. Take 20 mg of the prepared strontium titanate particles loaded with metallic palladium with a particle size of 50 nm, disperse them in 2 ml of ultrapure water, and evenly drop the dispersed liquid on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, place the conductive glass vertically in a 150 ml high-pressure autoclave. Pass in an inert gas to remove the air in the autoclave, then pass in high-purity methane gas to replace the autoclave with a methane atmosphere. Subsequently, close the outlet, adjust the inlet pressure of methane, adjust the methane pressure in the system to 0.3 MPa, and close the inlet. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 3 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. Analysis shows that the production rate of ethylene is 196 μmol·g -1 ·h -1 , the production rate of hydrogen is 341 μmol·g -1 ·h -1 , the conversion rate of methane is 754 μmol·g -1 ·h -1 , and the selectivity of ethylene is 52%.

[0024] Example 3

[0025] Preparation of Pd-loaded strontium titanate catalyst (0.3 wt% Pd / SrTiO3) by photodeposition method. Weigh 1.0 g of strontium titanate particles with a particle size of 50 nm, add them to 30 ml of methanol aqueous solution (methanol volume fraction is 10%), add chloropalladic acid according to the amount of 0.3% of the mass percentage of palladium in the product, stir evenly and transfer to a quartz autoclave. After purging with argon three times, under normal temperature and pressure and argon atmosphere, at a rotation speed of 300 r / min, irradiate with ultraviolet light of 365 nm for 1 h for photodeposition. Then wash with water three times and place in a vacuum drying oven at 60 °C for 12 h, grind and collect to obtain strontium titanate particles loaded with metallic palladium with a particle size of 50 nm. Take 20 mg of the prepared strontium titanate particles loaded with metallic palladium with a particle size of 50 nm, disperse them in 2 ml of ultrapure water, and evenly drop the dispersed liquid on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, place the conductive glass vertically in a 150 ml high-pressure autoclave. Pass in an inert gas to remove the air in the autoclave, then pass in high-purity methane gas to replace the inside of the autoclave with a methane atmosphere. Then close the outlet, adjust the inlet pressure of methane, adjust the methane pressure in the system to 0.3 MPa, and close the inlet. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 3 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. The analysis shows that the production rate of ethylene is 315 μmol·g -1 ·h -1 , the production rate of hydrogen is 665 μmol·g -1 ·h -1 , the conversion rate of methane is 954 μmol·g -1 ·h -1 , and the selectivity of ethylene is 66%.

[0026] Example 4

[0027] Preparation of Pd-loaded strontium titanate catalyst (1.1 wt% Pd / SrTiO3) by photodeposition method. Weigh 1.0 g of strontium titanate particles with a particle size of 50 nm, add them to 30 ml of methanol aqueous solution (methanol volume fraction is 10%), add chloropalladic acid in an amount corresponding to 1.1% by mass of palladium in the product, stir evenly and transfer to a quartz autoclave. After purging with argon three times, under normal temperature and pressure and in an argon atmosphere, at a rotation speed of 300 r / min, irradiate with ultraviolet light at 365 nm for 1 h for photodeposition. Then wash with water three times and place in a vacuum drying oven at 60 °C for 12 h. Grind and collect to obtain strontium titanate particles loaded with metallic palladium with a particle size of 50 nm. Take 20 mg of the prepared strontium titanate particles loaded with metallic palladium with a particle size of 50 nm, disperse them in 2 ml of ultrapure water, and evenly drop the dispersed liquid on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, place the conductive glass vertically in a 150 ml high-pressure autoclave. Introduce an inert gas to remove the air in the autoclave, then introduce high-purity methane gas to replace the autoclave with a methane atmosphere. Subsequently, close the outlet, adjust the inlet pressure of methane, and adjust the methane pressure in the system to 0.3 MPa, then close the inlet. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 3 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. Analysis shows that the production rate of ethylene is 350 μmol·g -1 ·h -1 , the production rate of hydrogen is 712 μmol·g -1 ·h -1 , the conversion rate of methane is 932 μmol·g -1 ·h -1 , and the selectivity of ethylene is 75%.

[0028] Example 5

[0029] Preparation of Pd-loaded strontium titanate catalyst (1.5 wt% Pd / SrTiO3) by photodeposition method. Weigh 1.0 g of strontium titanate particles with a particle size of 50 nm, add them to 30 ml of methanol aqueous solution (methanol volume fraction is 10%), add chloropalladic acid according to the amount of 1.5% by mass of palladium in the product, stir evenly and transfer to a quartz autoclave. After purging with argon three times, under normal temperature and pressure, in an argon atmosphere, at a rotation speed of 300 r / min, irradiate with ultraviolet light of 365 nm for 1 h for photodeposition. Then wash with water three times and place in a vacuum drying oven at 60 °C for 12 h. Grind and collect to obtain strontium titanate particles loaded with metallic palladium with a particle size of 50 nm. Take 20 mg of the prepared strontium titanate particles loaded with metallic palladium with a particle size of 50 nm, disperse them in 2 ml of ultrapure water, and evenly drop the dispersed liquid on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, place the conductive glass vertically in a 150 ml high-pressure autoclave. Introduce an inert gas to remove the air in the autoclave, then introduce high-purity methane gas to replace the autoclave with a methane atmosphere. Subsequently, close the outlet, adjust the inlet pressure of methane, and adjust the methane pressure in the system to 0.3 MPa, then close the inlet. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 3 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. The analysis shows that the production rate of ethylene is 208 μmol·g -1 ·h -1 , the production rate of hydrogen is 351 μmol·g -1 ·h -1 , the conversion rate of methane is 682 μmol·g -1 ·h -1 , and the selectivity of ethylene is 61%.

[0030] Example 6

[0031] Preparation of Pd-loaded strontium titanate catalyst (2wt% Pd / SrTiO3) by photodeposition method. Weigh 1.0 g of strontium titanate particles with a particle size of 50 nm, add them to 30 ml of methanol aqueous solution (methanol volume fraction is 10%), add chloropalladic acid according to the amount of 2% by mass of palladium in the product, stir evenly and transfer to a quartz autoclave. After purging with argon three times, under normal temperature and pressure, in an argon atmosphere, at a rotation speed of 300 r / min, irradiate with ultraviolet light of 365 nm for 1 h for photodeposition. Then wash with water 3 times, place in a vacuum drying oven at 60 °C for 12 h, grind and collect to obtain strontium titanate particles loaded with metallic palladium with a particle size of 50 nm. Take 20 mg of the prepared strontium titanate particles loaded with metallic palladium with a particle size of 50 nm, disperse them in 2 ml of ultrapure water, and evenly drop the dispersed liquid on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, place the conductive glass vertically in a 150 ml high-pressure autoclave. Introduce an inert gas to remove the air in the autoclave, then introduce high-purity methane gas to replace the autoclave with a methane atmosphere. Subsequently, close the outlet, adjust the inlet pressure of methane, and adjust the methane pressure in the system to 0.3 MPa, then close the inlet. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 3 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. Analysis shows that the production rate of ethylene is 57 μmol·g -1 ·h -1 , the production rate of hydrogen is 198 μmol·g -1 ·h -1 , the conversion rate of methane is 347 μmol·g -1 ·h -1 , and the selectivity of ethylene is 33%.

[0032] Example 7

[0033] Preparation of Pt-loaded strontium titanate catalyst (0.7 wt% Pt / SrTiO3) by photodeposition method. Weigh 1.0 g of strontium titanate particles with a particle size of 50 nm, add them to 30 ml of methanol aqueous solution (methanol volume fraction is 10%), add chloroplatinic acid according to the amount with a platinum mass percentage of 0.7% in the product, stir evenly and transfer to a quartz autoclave. After purging with argon three times, under normal temperature and pressure, in an argon atmosphere, at a rotation speed of 300 r / min, irradiate with ultraviolet light of 365 nm for 1 h for photodeposition. Subsequently, wash with water three times, place in a vacuum drying oven at 60 °C for 12 h, grind and collect to obtain strontium titanate particles loaded with platinum with a particle size of 50 nm. Take 20 mg of the prepared strontium titanate particles loaded with platinum with a particle size of 50 nm, disperse them in 2 ml of ultrapure water, and evenly drop the dispersed liquid on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, place the conductive glass vertically in a 150 ml high-pressure autoclave. Pass in an inert gas to remove the air in the autoclave, then pass in high-purity methane gas to replace the autoclave with a methane atmosphere. Subsequently, close the outlet, adjust the inlet pressure of methane, adjust the methane pressure in the system to 0.3 MPa, and close the inlet. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 3 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. Analysis shows that the production rate of ethylene is 177 μmol·g -1 ·h -1 , the production rate of hydrogen is 375 μmol·g -1 ·h -1 , the conversion rate of methane is 843 μmol·g -1 ·h -1 , and the selectivity of ethylene is 42%.

[0034] Example 8

[0035] Preparation of Au-loaded strontium titanate catalyst (0.7wt% Au / SrTiO3) by photodeposition method. Weigh 1.0 g of strontium titanate particles with a particle size of 50 nm, add them to 30 ml of methanol aqueous solution (methanol volume fraction is 10%), add chloroauric acid according to the amount of 0.7% by mass of gold in the product, stir evenly and transfer to a quartz autoclave. After purging with argon three times, under normal temperature and pressure, in an argon atmosphere, at a rotation speed of 300 r / min, irradiate with ultraviolet light of 365 nm for 1 h for photodeposition. Then wash with water 3 times and place in a vacuum drying oven at 60 °C for 12 h, grind and collect to obtain strontium titanate particles loaded with metallic gold with a particle size of 50 nm. Take 20 mg of the prepared strontium titanate particles loaded with metallic gold with a particle size of 50 nm and disperse them in 2 ml of ultrapure water. The dispersed liquid is evenly dropped on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, place the conductive glass vertically in a 150 ml high-pressure autoclave. Pass in an inert gas to remove the air in the autoclave, then pass in high-purity methane gas to replace the inside of the autoclave with a methane atmosphere. Then close the outlet, adjust the inlet pressure of methane, and adjust the methane pressure in the system to 0.3 MPa, then close the inlet. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 3 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. Analysis shows that the production rate of ethylene is 69 μmol·g -1 ·h -1 , the production rate of hydrogen is 241 μmol·g -1 ·h -1 , the conversion rate of methane is 514 μmol·g -1 ·h -1 , and the selectivity of ethylene is 27%.

[0036] Example 9

[0037] Preparation of palladium-loaded strontium titanate catalyst (0.7wt% Pd / SrTiO3) by photodeposition method. Weigh 1.0 g of strontium titanate particles with a particle size of 100 nm, add them to 30 ml of methanol aqueous solution (methanol volume fraction is 10%), add chloropalladic acid according to the amount of 0.7% by mass of palladium in the product, stir evenly and transfer to a quartz autoclave. After purging with argon three times, under normal temperature and pressure, in an argon atmosphere, at a rotation speed of 300 r / min, irradiate with ultraviolet light of 365 nm for 1 h for photodeposition. Then wash with water three times and place in a vacuum drying oven at 60 °C for 12 h. Grind and collect to obtain strontium titanate particles loaded with metallic palladium with a particle size of 100 nm. Take 20 mg of the prepared strontium titanate particles loaded with metallic palladium with a particle size of 100 nm, disperse them in 2 ml of ultrapure water, and evenly drop the dispersed liquid on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, place the conductive glass vertically in a 150 ml high-pressure autoclave. Pass in an inert gas to remove the air in the autoclave, then pass in high-purity methane gas to replace the atmosphere in the autoclave with a methane atmosphere. Then close the outlet, adjust the inlet pressure of methane, and adjust the methane pressure in the system to 0.3 MPa, and then close the inlet. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 3 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. Analysis shows that the production rate of ethylene is 83 μmol·g -1 ·h -1 , the production rate of hydrogen is 245 μmol·g -1 ·h -1 , the conversion rate of methane is 538 μmol·g -1 ·h -1 , and the selectivity of ethylene is 31%.

[0038] Example 10

[0039] Preparation of Palladium-Loaded Strontium Titanate Catalyst (0.7wt% Pd / SrTiO3) by Photodeposition Method. Weigh 1.0 g of strontium titanate particles with a particle size of 300 nm, add them to 30 ml of methanol aqueous solution (methanol volume fraction is 10%), add chloropalladic acid according to the amount of 0.7% of the mass percentage of palladium in the product, stir evenly and transfer to a quartz autoclave. After purging with argon three times, under normal temperature and pressure, in an argon atmosphere, at a rotation speed of 300 r / min, irradiate with ultraviolet light of 365 nm for 1 h for photodeposition. Then wash with water 3 times, place in a vacuum drying oven at 60 °C for 12 h, grind and collect to obtain strontium titanate particles loaded with metallic palladium with a particle size of 300 nm. Take 20 mg of the prepared strontium titanate particles loaded with metallic palladium with a particle size of 300 nm, disperse them in 2 ml of ultrapure water, and evenly drop the dispersed liquid on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, place the conductive glass vertically in a 150 ml high-pressure autoclave. Pass in an inert gas to remove the air in the autoclave, then pass in high-purity methane gas to replace the atmosphere in the autoclave with a methane atmosphere. Then close the outlet, adjust the inlet pressure of methane, adjust the methane pressure in the system to 0.3 MPa, and close the inlet. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 3 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. Analysis shows that the production rate of ethylene is 16 μmol·g -1 ·h -1 , the production rate of hydrogen is 154 μmol·g -1 ·h -1 , the conversion rate of methane is 271 μmol·g -1 ·h -1 , and the selectivity of ethylene is 12%.

[0040] Example 11

[0041] Preparation of Palladium-Loaded Strontium Titanate Catalyst (0.7wt% Pd / SrTiO3) by Photodeposition Method. Weigh 1.0 g of strontium titanate particles with a particle size of 50 nm, add them to 30 ml of methanol aqueous solution (methanol volume fraction is 10%), add chloropalladic acid according to the amount of 0.7% by mass of palladium in the product, stir evenly and transfer to a quartz autoclave. After purging with argon three times, under normal temperature and pressure, in an argon atmosphere, at a rotation speed of 300 r / min, irradiate with ultraviolet light at 365 nm for 1 h for photodeposition. Then wash with water three times and place in a vacuum drying oven at 60 °C for 12 h. Grind and collect to obtain strontium titanate particles loaded with metallic palladium with a particle size of 50 nm. Take 20 mg of the prepared strontium titanate particles loaded with metallic palladium with a particle size of 50 nm and disperse them in 2 ml of ultrapure water. The dispersed liquid is evenly dropped on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, place the conductive glass vertically in a 150 ml high-pressure autoclave. Pass in an inert gas to remove the air in the autoclave, then pass in high-purity methane gas to replace the autoclave with a methane atmosphere. Then close the outlet, adjust the inlet pressure of methane, and adjust the methane pressure in the system to 0.1 MPa, then close the inlet. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 3 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. Analysis shows that the production rate of ethylene is 276 μmol·g -1 ·h -1 , the production rate of hydrogen is 353 μmol·g -1 ·h -1 , the conversion rate of methane is 698 μmol·g -1 ·h -1 , and the selectivity of ethylene is 79%.

[0042] Example 12

[0043] Preparation of Palladium-Loaded Strontium Titanate Catalyst (0.7wt% Pd / SrTiO3) by Photodeposition Method. Weigh 1.0 g of strontium titanate nanoparticles with a particle size of 50 nm, add them to 30 ml of methanol aqueous solution (methanol volume fraction is 10%), add chloropalladic acid according to the amount with a palladium mass percentage of 0.7% in the product, stir evenly and transfer to a quartz autoclave. After purging with argon three times, under normal temperature and pressure, in an argon atmosphere, at a rotation speed of 300 r / min, irradiate with ultraviolet light of 365 nm for 1 h for photodeposition. Then wash with water three times, place in a vacuum drying oven at 60 °C for 12 h, grind and collect to obtain strontium titanate particles loaded with metallic palladium with a particle size of 50 nm. Take 20 mg of the prepared strontium titanate particles loaded with metallic palladium with a particle size of 50 nm, disperse them in 2 ml of ultrapure water, and evenly drop the dispersed liquid on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, place the conductive glass vertically in a 150 ml high-pressure autoclave. Introduce an inert gas to remove the air in the autoclave, then introduce high-purity methane gas to replace the autoclave with a methane atmosphere. Subsequently, close the outlet, adjust the inlet pressure of methane, adjust the methane pressure in the system to 0.5 MPa, and close the inlet. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 3 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. Analysis shows that the production rate of ethylene is 478 μmol·g -1 ·h -1 , the production rate of hydrogen is 698 μmol·g -1 ·h -1 , the conversion rate of methane is 1257 μmol·g -1 ·h -1 , and the selectivity of ethylene is 76%.

[0044] Example 13

[0045] Preparation of palladium-loaded strontium titanate catalyst (0.7 wt% Pd / SrTiO3) by photodeposition method. Weigh 1.0 g of strontium titanate particles with a particle size of 50 nm, add them to 30 ml of methanol aqueous solution (methanol volume fraction is 10%), add chloropalladic acid according to the amount of 0.7% by mass of palladium in the product, stir evenly and transfer to a quartz autoclave. After purging with argon three times, under normal temperature and pressure, in an argon atmosphere, at a rotation speed of 300 r / min, irradiate with ultraviolet light of 365 nm for 1 h for photodeposition. Subsequently, wash with water three times and place in a vacuum drying oven at 60 °C for 12 h, grind and collect to obtain strontium titanate particles loaded with metallic palladium with a particle size of 50 nm. Take 20 mg of the prepared strontium titanate particles loaded with metallic palladium with a particle size of 50 nm, disperse them in 2 ml of ultrapure water, and evenly drop the dispersed liquid on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, place the conductive glass vertically in a 150 ml high-pressure autoclave. Pass in an inert gas to remove the air in the autoclave, then pass in high-purity methane gas to replace the autoclave with a methane atmosphere. Subsequently, close the outlet, adjust the inlet pressure of methane, and adjust the methane pressure in the system to 0.7 MPa, then close the inlet. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 3 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. Analysis shows that the production rate of ethylene is 506 μmol·g -1 ·h -1 , the production rate of hydrogen is 817 μmol·g -1 ·h -1 , the conversion rate of methane is 1425 μmol·g -1 ·h -1 , and the selectivity of ethylene is 71%.

[0046] Example 14

[0047] Preparation of palladium-loaded strontium titanate catalyst (0.7 wt% Pd / SrTiO3) by photodeposition method. Weigh 1.0 g of strontium titanate particles with a particle size of 50 nm, add them to 30 ml of methanol aqueous solution (methanol volume fraction is 10%), add chloropalladic acid according to the amount of 0.7% of the mass percentage of palladium in the product, stir evenly and transfer to a quartz autoclave. After purging with argon three times, under normal temperature and pressure and argon atmosphere, at a rotation speed of 300 r / min, irradiate with ultraviolet light of 365 nm for 1 h for photodeposition. Then wash with water 3 times and place in a vacuum drying oven at 60 °C for 12 h, grind and collect to obtain strontium titanate particles loaded with metallic palladium with a particle size of 50 nm. Take 20 mg of the prepared strontium titanate particles loaded with metallic palladium with a particle size of 50 nm and disperse them in 2 ml of ultrapure water. The dispersed liquid is evenly dropped on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, place the conductive glass vertically in a 150 ml high-pressure autoclave. Introduce an inert gas to remove the air in the autoclave, then introduce high-purity methane gas to replace the autoclave with a methane atmosphere. Subsequently, close the outlet, adjust the inlet pressure of methane, and adjust the methane pressure in the system to 1 MPa, then close the inlet. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 3 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. The analysis shows that the production rate of ethylene is 540 μmol·g -1 ·h -1 , the production rate of hydrogen is 938 μmol·g -1 ·h -1 , the conversion rate of methane is 1746 μmol·g -1 ·h -1 , and the selectivity of ethylene is 62%.

[0048] Example 15

[0049] Preparation of Palladium-Loaded Strontium Titanate Catalyst (0.7wt% Pd / SrTiO3) by Photodeposition Method. Weigh 1.0 g of strontium titanate particles with a particle size of 50 nm, add them to 30 ml of methanol aqueous solution (methanol volume fraction is 10%), add chloropalladic acid according to the amount of 0.7% of the mass percentage of palladium in the product, stir evenly and transfer to a quartz autoclave. After purging with argon three times, under normal temperature and pressure and argon atmosphere, at a rotation speed of 300 r / min, irradiate with ultraviolet light at 365 nm for 1 h for photodeposition. Then wash with water 3 times and place in a vacuum drying oven at 60 °C for 12 h. Grind and collect to obtain strontium titanate particles loaded with metallic palladium with a particle size of 50 nm. Take 20 mg of the prepared strontium titanate particles loaded with metallic palladium with a particle size of 50 nm, disperse them in 2 ml of ultrapure water, and evenly drop the dispersed liquid on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, place the conductive glass vertically in a 150 ml high-pressure autoclave. Pass in an inert gas to remove the air in the autoclave, then pass in high-purity methane gas to replace the atmosphere in the autoclave with a methane atmosphere. Subsequently, close the outlet, adjust the inlet pressure of methane, and adjust the methane pressure in the system to 0.3 MPa, then close the inlet. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 1 h. The gas after the reaction is connected to a gas chromatograph through a six-way valve. The analysis shows that the production rate of ethylene is 160 μmol·g -1 ·h -1 , the production rate of hydrogen is 263 μmol·g -1 ·h -1 , the conversion rate of methane is 386 μmol·g -1 ·h -1 , and the selectivity of ethylene is 81%.

[0050] Example 16

[0051] Preparation of Palladium-Loaded Strontium Titanate Catalyst (0.7wt% Pd / SrTiO3) by Photodeposition Method. Weigh 1.0 g of strontium titanate particles with a particle size of 50 nm, add them to 30 ml of methanol aqueous solution (methanol volume fraction is 10%), add chloropalladic acid according to the amount of 0.7% by mass of palladium in the product, stir evenly and transfer to a quartz autoclave. After purging with argon three times, under normal temperature and pressure, in an argon atmosphere, at a rotation speed of 300 r / min, irradiate with ultraviolet light of 365 nm for 1 h for photodeposition. Then wash with water 3 times and place in a vacuum drying oven at 60 °C for 12 h. Grind and collect to obtain strontium titanate particles loaded with metallic palladium with a particle size of 50 nm. Take 20 mg of the prepared strontium titanate particles loaded with metallic palladium with a particle size of 50 nm, disperse them in 2 ml of ultrapure water, and evenly drop the dispersed liquid on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, place the conductive glass vertically in a 150 ml high-pressure autoclave. Introduce an inert gas to remove the air in the autoclave, then introduce high-purity methane gas to replace the autoclave with a methane atmosphere. Subsequently, close the outlet, adjust the inlet pressure of methane, and adjust the methane pressure in the system to 0.3 MPa, then close the inlet. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 10 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. Analysis shows that the production rate of ethylene is 521 μmol·g -1 ·h -1 , the production rate of hydrogen is 1883 μmol·g -1 ·h -1 , the conversion rate of methane is 2981 μmol·g -1 ·h -1 , and the selectivity of ethylene is 35%.

[0052] Example 17

[0053] Preparation of Palladium-Loaded Strontium Titanate Catalyst (0.7wt% Pd / SrTiO3) by Photodeposition Method. Weigh 1.0 g of strontium titanate nanoparticles with a particle size of 50 nm, add them to 30 ml of methanol aqueous solution (methanol volume fraction is 10%), add chloropalladic acid according to the amount of 0.7% of the mass percentage of palladium in the product, stir evenly and transfer to a quartz autoclave. After purging with argon three times, under normal temperature and pressure, in an argon atmosphere, at a rotation speed of 300 r / min, irradiate with ultraviolet light at 365 nm for 1 h for photodeposition. Then wash with water three times and place in a vacuum drying oven at 60 °C for 12 h. Grind and collect to obtain strontium titanate particles loaded with metallic palladium with a particle size of 50 nm. Take 20 mg of the prepared strontium titanate particles loaded with metallic palladium with a particle size of 50 nm, disperse them in 2 ml of ultrapure water, and evenly drop the dispersed liquid on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, place the conductive glass vertically in a 150 ml high-pressure autoclave. Introduce an inert gas to remove the air in the autoclave, then introduce high-purity methane gas to replace the atmosphere in the autoclave with a methane atmosphere. Subsequently, close the outlet, adjust the inlet pressure of methane, and adjust the methane pressure in the system to 0.3 MPa, then close the inlet. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 15 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. Analysis shows that the production rate of ethylene is 521 μmol·g -1 ·h -1 , the production rate of hydrogen is 1954 μmol·g -1 ·h -1 , the conversion rate of methane is 3857 μmol·g -1 ·h -1 , and the selectivity of ethylene is 28%.

[0054] Example 18

[0055] Preparation of Palladium-Loaded Strontium Titanate Catalyst (0.7wt% Pd / SrTiO3) by Photodeposition Method. Weigh 1.0 g of strontium titanate particles with a particle size of 50 nm, add them to 30 ml of methanol aqueous solution (methanol volume fraction is 10%), add chloropalladic acid according to the amount of 0.7% by mass of palladium in the product, stir evenly and transfer to a quartz autoclave. After purging with argon three times, under normal temperature and pressure and argon atmosphere, at a rotation speed of 300 r / min, irradiate with ultraviolet light of 365 nm for 1 h for photodeposition. Then wash with water 3 times and place in a vacuum drying oven at 60 °C for 12 h. Grind and collect to obtain strontium titanate particles loaded with metallic palladium with a particle size of 50 nm. Take 20 mg of the prepared strontium titanate particles loaded with metallic palladium with a particle size of 50 nm and disperse them in 2 ml of ultrapure water. The dispersed liquid is evenly dropped on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, place the conductive glass vertically in a 150 ml high-pressure autoclave. Introduce an inert gas to remove the air in the autoclave, and then introduce high-purity methane gas to replace the autoclave with a methane atmosphere. Then close the outlet, adjust the inlet pressure of methane, and adjust the methane pressure in the system to 0.3 MPa. Close the inlet. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 24 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. Analysis shows that the production rate of ethylene is 349 μmol·g -1 ·h -1 , the production rate of hydrogen is 4307 μmol·g -1 ·h -1 , the conversion rate of methane is 6354 μmol·g -1 ·h -1 , and the selectivity of ethylene is 11%.

[0056] Example 19

[0057] Preparation of Palladium-Loaded Strontium Titanate Catalyst (0.7wt% Pd / SrTiO3) by Photodeposition Method. Weigh 1.0 g of strontium titanate particles with a particle size of 50 nm, add them to 30 ml of methanol aqueous solution (methanol volume fraction is 10%), add chloropalladic acid according to the amount of 0.7% by mass of palladium in the product, stir evenly and transfer to a quartz autoclave. After purging with argon three times, under normal temperature and pressure, in an argon atmosphere, at a rotation speed of 300 r / min, irradiate with ultraviolet light of 365 nm for 1 h for photodeposition. Then wash with water three times and place in a vacuum drying oven at 60 °C for 12 h, grind and collect to obtain strontium titanate particles loaded with metallic palladium with a particle size of 50 nm. Disperse 10 mg of the prepared strontium titanate particles loaded with metallic palladium with a particle size of 50 nm in 2 ml of ultrapure water, and evenly drop the dispersed liquid on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, place the conductive glass vertically in a 150 ml high-pressure autoclave. Introduce an inert gas to remove the air in the autoclave, then introduce high-purity methane gas to replace the atmosphere in the autoclave with a methane atmosphere. Subsequently, close the outlet, adjust the inlet pressure of methane, and adjust the methane pressure in the system to 0.3 MPa, then close the inlet. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 3 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. Analysis shows that the production rate of ethylene is 255 μmol·g -1 ·h -1 , the production rate of hydrogen is 443 μmol·g -1 ·h -1 , the conversion rate of methane is 672 μmol·g -1 ·h -1 , and the selectivity of ethylene is 76%.

[0058] Example 20

[0059] Preparation of palladium-loaded strontium titanate catalyst (0.7wt% Pd / SrTiO3) by photodeposition method. Weigh 1.0 g of strontium titanate particles with a particle size of 50 nm, add them to 30 ml of methanol aqueous solution (methanol volume fraction is 10%), add chloropalladic acid according to the amount of 0.7% by mass of palladium in the product, stir evenly and transfer to a quartz autoclave. After purging with argon three times, under normal temperature and pressure, in an argon atmosphere, at a rotation speed of 300 r / min, irradiate with ultraviolet light of 365 nm for 1 h for photodeposition. Then wash with water 3 times and place in a vacuum drying oven at 60 °C for 12 h, grind and collect to obtain strontium titanate particles loaded with metallic palladium with a particle size of 50 nm. 40 mg of the prepared strontium titanate particles loaded with metallic palladium with a particle size of 50 nm are dispersed in 2 ml of ultrapure water, and the dispersed liquid is evenly dropped on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, place the conductive glass vertically in a 150 ml high-pressure autoclave. Introduce an inert gas to remove the air in the autoclave, then introduce high-purity methane gas to replace the atmosphere in the autoclave with a methane atmosphere. Then close the outlet, adjust the inlet pressure of methane, and adjust the methane pressure in the system to 0.3 MPa, then close the inlet. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 3 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. The analysis shows that the production rate of ethylene is 705 μmol·g -1 ·h -1 , the production rate of hydrogen is 923 μmol·g -1 ·h -1 , the conversion rate of methane is 1960 μmol·g -1 ·h -1 , and the selectivity of ethylene is 72%.

[0060] Example 21

[0061] Preparation of Palladium-Loaded Strontium Titanate Catalyst (0.7wt% Pd / SrTiO3) by Photodeposition Method. Weigh 1.0 g of strontium titanate particles with a particle size of 50 nm, add them to 30 ml of methanol aqueous solution (methanol volume fraction is 10%), add chloropalladic acid according to the amount of 0.7% by mass of palladium in the product, stir evenly and transfer to a quartz autoclave. After purging with argon three times, under normal temperature and pressure and argon atmosphere, at a rotation speed of 300 r / min, irradiate with ultraviolet light of 365 nm for 1 h for photodeposition. Then wash with water three times and place in a vacuum drying oven at 60 °C for 12 h, grind and collect to obtain strontium titanate particles loaded with metallic palladium with a particle size of 50 nm. Take 20 mg of the prepared strontium titanate particles loaded with metallic palladium with a particle size of 50 nm, disperse them in 2 ml of ultrapure water, and evenly drop the dispersed liquid on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, place the conductive glass vertically in a 150 ml high-pressure autoclave. Introduce an inert gas to remove the air in the autoclave, then introduce high-purity methane gas to replace the atmosphere in the autoclave with a methane atmosphere. Subsequently, close the outlet, adjust the inlet pressure of methane, and adjust the methane pressure in the system to 0.3 MPa, then close the inlet. Turn on a 300 W LED lamp with a light wavelength of 400 nm and react for 3 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. Analysis shows that the production rate of ethylene is 16 μmol·g -1 ·h -1 , the production rate of hydrogen is 34 μmol·g -1 ·h -1 , the conversion rate of methane is 76 μmol·g -1 ·h -1 , and the selectivity of ethylene is 42%.

[0062] Example 22

[0063] Preparation of Palladium-Loaded Strontium Titanate Catalyst (0.7wt% Pd / SrTiO3) by Impregnation Method. Weigh 1.0 g of strontium titanate nanoparticles with a particle size of 50 nm into a beaker, first add 40 mL of ultrapure water, and add chloropalladic acid in an amount corresponding to 0.7% by mass of palladium in the product. The solution is stirred at room temperature for 12 hours, then evaporated to dryness at 100 °C on a heating plate. The dried solid is ground into powder, and then calcined successively in air atmosphere and hydrogen atmosphere. After grinding and collection, strontium titanate particles loaded with metallic palladium with a particle size of 50 nm are obtained. Take 20 mg of the prepared strontium titanate particles loaded with metallic palladium with a particle size of 50 nm, disperse them in 2 ml of ultrapure water, and evenly drop the dispersed liquid on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, the conductive glass is vertically placed in a 150 ml high-pressure reactor. Inert gas is introduced to remove the air in the reactor, and then high-purity methane gas is introduced to replace the atmosphere in the reactor with a methane atmosphere. Subsequently, the outlet is closed, the inlet pressure of methane is adjusted, and the methane pressure in the system is adjusted to 0.3 MPa. Then the inlet is closed. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 3 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. Analysis shows that the production rate of ethylene is 339 μmol·g -1 ·h -1 , the production rate of hydrogen is 323 μmol·g -1 ·h -1 , the conversion rate of methane is 941 μmol·g -1 ·h -1 , and the selectivity of ethylene is 72%

[0064] Comparative Example 1

[0065] Using strontium titanate with a particle size of 50 nm as the photocatalyst. Take 20 mg of strontium titanate with a particle size of 50 nm, disperse it in 2 ml of ultrapure water, and evenly drop the dispersed liquid on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, the conductive glass is vertically placed in a 150 ml high-pressure reactor. Inert gas is introduced to remove the air in the reactor, and then high-purity methane gas is introduced to replace the atmosphere in the reactor with a methane atmosphere. Subsequently, the outlet is closed, the inlet pressure of methane is adjusted, and the methane pressure in the system is adjusted to 0.3 MPa. Then the inlet is closed. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 3 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. Analysis shows that the production rate of ethylene is 22 μmol·g -1 ·h -1 , the production rate of hydrogen is 12 μmol·g -1 ·h -1 , the conversion rate of methane is 110 μmol·g -1 ·h -1 , and the selectivity of ethylene is 41%.

[0066] Comparative Example 2

[0067] Using commercial zinc oxide as the photocatalyst. Take 20 mg of commercial zinc oxide nanoparticles and disperse them in 2 ml of ultrapure water. The dispersed liquid is evenly dropped on the two side surfaces of a 4 cm × 5 cm conductive glass. After drying at 60 °C, the conductive glass is vertically placed in a 150 ml high-pressure reactor. An inert gas is introduced to remove the air in the reactor, and then high-purity methane gas is introduced to replace the inside of the reactor with a methane atmosphere. Subsequently, the outlet is closed, the inlet pressure of methane is adjusted, and the methane pressure in the system is adjusted to 0.3 MPa. The inlet is closed. Turn on a 300 W LED lamp with a light wavelength of 300 nm and react for 3 hours. The gas after the reaction is connected to a gas chromatograph through a six-way valve. Analysis shows that the production rate of ethylene is 0 μmol·g -1 ·h -1 and the production rate of hydrogen is 112 μmol·g -1 ·h -1 and the conversion rate of methane is 274 μmol·g -1 ·h -1 and the selectivity of ethylene is 0%.

Claims

1. A method for photocatalytic dehydrogenative coupling of methane, characterized in that: Disperse the metal-loaded strontium titanate catalyst on the conductive glass and place it in a reaction kettle. Use an inert gas to fully displace the atmosphere in the reaction kettle, introduce methane gas to a specified pressure, irradiate with light, and react to generate ethylene and hydrogen; The loaded metal in the metal-loaded strontium titanate catalyst is one or more of palladium, platinum, and gold; The content of the loaded metal in the metal-loaded strontium titanate catalyst is 0.1 wt% - 2 wt% by mass; The metal-loaded strontium titanate catalyst is prepared by a photodeposition method or an impregnation method; The reaction pressure of the reaction substrate methane is 0.1 - 1 MPa; The wavelength range of the light source is 300 nm - 800 nm; Dispersion concentration of metal-loaded strontium titanate catalyst on conductive glass: 0.1 mg·cm -2 ~2 mg·cm -2 ; The photoreaction time is 1 - 24 hours; The particle size of strontium titanate is 20 nm - 1000 nm.

2. The method according to claim 1, wherein: The content of the loaded metal in the metal-loaded strontium titanate catalyst is 0.3 wt% - 1.1 wt% by mass.

3. According to the method described in claim 1, characterized in that: The reaction pressure of the reaction substrate methane is 0.3 MPa - 0.5 MPa.

4. According to the method described in claim 1, characterized in that: The wavelength range of the light source is 300 nm - 400 nm.

5. According to the method described in claim 1, characterized in that: The dispersion concentration of the metal-loaded strontium titanate catalyst on the conductive glass is 0.5 mg·cm -2 ~1mg·cm -2 .

6. According to the method described in claim 1, characterized in that: The photoreaction time is 3 - 6 hours.

7. According to the method described in claim 1, characterized in that: The particle size of strontium titanate is 50 nm - 200 nm.