A supported photocatalyst, its preparation method and its use in the decomposition of hydrogen sulfide

Abstract

The application discloses a supported photocatalyst, a preparation method thereof and application of the photocatalyst in hydrogen sulfide decomposition. x MXene, wherein T x represents surface functional groups -O, -F, -OH) and a semiconductor material cadmium sulfide (CdS) loaded on the surface of the material, namely CdS / Mo2CT x photocatalyst; the photocatalyst directly decomposes hydrogen sulfide in a special quartz reactor filled with the supported photocatalyst to form a micro reaction bed, pure hydrogen sulfide (H2S) gas is introduced, and then the decomposition is carried out under irradiation of a laser; in the process, hydrogen sulfide is decomposed into hydrogen (H2) and sulfur (S). The application has the advantages of simple operation, mild conditions, high decomposition efficiency and the like, and can realize direct decomposition of hydrogen sulfide under the action of light only.

Description

Technical Field

[0001] This invention belongs to the field of photocatalysis technology, and relates to a supported photocatalyst, its preparation method, and its application in the decomposition of hydrogen sulfide. Background Technology

[0002] Hydrogen sulfide (H2S) is a gas widely present in nature and industrial production. Even at extremely low concentrations, it has a very unpleasant, pungent odor (like rotten eggs). Even trace amounts (20 ppm) in the environment can cause irreversible damage to the human body. Human industrial activities such as oil and gas extraction and crude oil refining inevitably produce H2S. Currently, global H2S production has already exceeded 10 million tons per year and continues to grow. Therefore, the effective treatment and utilization of H2S has always been an important research topic.

[0003] Currently, the Claus process is widely used in industry to treat H2S, converting it into water (H2O) and sulfur (S) through incomplete oxidation. However, the reaction requires very high temperatures (>850℃), resulting in significant energy consumption. Furthermore, high-quality hydrogen energy is directly converted into water, leading to resource waste. In recent years, to address the shortcomings of the Claus process, some novel H2S decomposition technologies have been developed, such as electrocatalysis, plasma-induced decomposition, microwave-assisted decomposition, and high-temperature catalytic conversion. However, these methods generally suffer from harsh reaction conditions, difficulty in process control, excessive energy consumption, and complex and expensive reaction equipment, thus limiting their further development. Therefore, there is a need to find a simpler, more efficient, and environmentally friendly decomposition technology.

[0004] Photocatalysis, as one of the most promising technologies of the 21st century, boasts numerous advantages such as high resource utilization, simple and controllable reaction processes, and wide applicability, providing an ideal pathway for the direct decomposition of H2S. In 1982, Enrico Borgarello et al. first attempted to decompose H2S in the liquid phase using photocatalysis. However, this process required the assistance of an alkaline intermediate reagent, making the reaction complex, and sulfur was also difficult to extract effectively in the liquid phase. Therefore, the advantages of direct gas-solid phase decomposition of hydrogen sulfide became apparent. In 1992, SANaman et al. discovered that H2S could be decomposed using photocatalysis in the V… x S yUnder the combined effect of light and illumination, the conversion rate was increased by 45% compared to thermocatalysis under the same conditions, and the activation energy of the reaction was reduced by more than 50%. However, this process still requires high temperature to drive it. Later, MingheLou et al. developed a novel plasmonic photocatalyst, which was prepared by loading gold (Au) nanoparticles onto silica (SiO2). It can directly decompose H2S into hydrogen (H2) and sulfur (S) under light irradiation alone, but the hydrogen production rate is only 18000 μmol·g. -1 ·h -1 Meanwhile, the catalyst has poor stability.

[0005] Therefore, there is an urgent need to develop a new type of photocatalyst that is cheaper, more efficient, and more stable, which can further improve the decomposition efficiency of H2S under light irradiation alone and the stability of related catalysts under high light power. Summary of the Invention

[0006] To address the problems of existing technologies that make it difficult to directly decompose H2S into hydrogen (H2) and sulfur (S) in the gas-solid phase, as well as the insufficient activity and stability of related catalysts, this invention provides a supported photocatalyst, its preparation method, and its application in hydrogen sulfide decomposition. The supported photocatalyst works in conjunction with light to achieve the direct decomposition of H2S under light irradiation alone.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A method for preparing a supported photocatalyst includes the following steps:

[0009] Step A: The precursor Mo2Ga2CMAX phase was etched using a hydrothermal method to obtain multilayered molybdenum carbide, which was named M-Mo2CT. x Then, after centrifugation with water and ethanol respectively, vacuum drying was performed, followed by grinding to obtain powder.

[0010] Step B: Using a 25% (w / w) aqueous solution of tetramethylammonium hydroxide (TMAOH) as an intercalating agent, M-Mo2CT was... x Intercalation was performed to obtain a few layers of molybdenum carbide, which was named F-Mo2CT. x The supernatant dispersion was accumulated through repeated ice bath sonication and centrifugation, and then freeze-dried to obtain fluffy F-Mo2CT. x solid;

[0011] Step C: The F-Mo2CT obtained in the previous step... xAfter the solid was redispersed in water, cadmium nitrate tetrahydrate (Cd(NO3)2·4H2O) was added dropwise as a cadmium source. After ultrasonic treatment, an aqueous solution of ammonium sulfide ((NH4)2S) with a mass fraction of 20-26% was added dropwise as a sulfur source. After the reaction was completed, the mixture was centrifuged with water and ethanol respectively, vacuum dried, and ground to obtain CdS / Mo2CT. x Solid photocatalyst, i.e., the supported photocatalyst.

[0012] In this invention:

[0013] Furthermore, in steps A through C, the reactions all occur in a Shrek bottle, and argon gas is required to prevent the materials from being oxidized during the reaction.

[0014] Furthermore, the etching of the precursor Mo2Ga2C MAX phase by hydrothermal method described in step A is carried out according to the following ratio: the amount of precursor Mo2Ga2C is 1-2g, and a mixed solution of 1-2g NH4F and 20-40ml 6M HCl is used as the etching solution. The etching is carried out in a high-pressure reactor at 180℃ for 24h. The precursor Mo2Ga2C needs to be added to the etching solution slowly to prevent violent reaction.

[0015] Furthermore, step B involves using a 25% (w / w) aqueous solution of tetramethylammonium hydroxide (TMAOH) as an intercalating agent for M-Mo2CT. x Intercalation is performed according to the following ratio, M-Mo2CT x The dosage is 200-400 mg, which is added to 15-30 ml of a 25% tetramethylammonium hydroxide aqueous solution, and then stirred at room temperature for 16-24 h.

[0016] Furthermore, in step C, the following proportions are used: 1.15g of cadmium nitrate tetrahydrate is dissolved in 10ml of ultrapure water; 1.3ml of ammonium sulfide solution is used; and F-Mo2CT... x The dosage is 10.8-64.6 mg and dispersed in 20 ml of ultrapure water; simultaneously, according to CdS / Mo2CT... x F-Mo2CT in solid photocatalysts x The CdS mass fractions (1.5%, 2.5%, 4%, 5%, 6%, 7%, 8%, 12%) are named CM-1.5, CM-2.5, CM-4, CM-5, CM-6, CM-7, CM-8, and CM-12, respectively.

[0017] This invention also relates to a supported photocatalyst, obtained using the above-described method for preparing a supported photocatalyst, wherein the supported photocatalyst comprises a two-dimensional plasmonic material, few-layer molybdenum carbide (F-Mo2CT). x MXene) and cadmium sulfide (CdS) semiconductor material loaded on its surface, F-Mo2CT x Prepared by etching, intercalation, and stripping of the precursor Mo2Ga2C, CdS is loaded onto F-Mo2CT via precipitation. x The resulting composite material is CdS / Mo2CT. x Photocatalyst.

[0018] The present invention also relates to the application of the above-mentioned supported photocatalyst in the direct photocatalytic decomposition of hydrogen sulfide. Specifically, the above-mentioned supported photocatalyst is filled into a specially made quartz reactor to form a micro-reaction bed. After pure H2S gas is introduced, H2S is decomposed into hydrogen and sulfur under laser irradiation.

[0019] Furthermore, when filling the supported photocatalyst, it is necessary to first fill the thin tube of the specially made quartz reactor with 2mm thick quartz wool near the tube opening, then fill in 5mg of catalyst, and then compact it with a solid aluminum rod to the quartz wool to form a micro gas-solid phase reaction bed.

[0020] Furthermore, before introducing pure H2S gas, the pipeline needs to be leak-tested with inert gas to ensure that the pipeline is properly sealed.

[0021] Furthermore, the reaction is carried out under laser irradiation, using laser wavelengths of 405nm, 450nm, 470nm, 520nm, 577nm, 637nm, and 677nm, preferably 405nm and 450nm; the spot size is 2.00-2.54mm; and the optical power density is 4.2-13.7W / cm². 2 The preferred value is 11.0-13.7 W / cm². 2 .

[0022] Furthermore, the decomposition yields a mixed gas, which first needs to pass through a sodium hydroxide solution to remove unreacted hydrogen sulfide, and then be dried with silica gel before being detected by gas chromatography.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. The supported photocatalyst of this invention does not require the use of precious metal materials, but rather a two-dimensional F-Mo2CT with plasmon properties. xUsing MXene as a carrier satisfies both high optical coupling characteristics and allows for loading and control of its surface, solving the problem of difficulty in modifying conventional polaritonic metal materials such as Au, Ag, and Cu. It also results in lower preparation costs and better light absorption performance.

[0025] 2. The application of the supported photocatalyst described in this invention in the direct photocatalytic decomposition of hydrogen sulfide has no special requirements on the composition of H2S gas, and can achieve the decomposition of H2S with different concentrations, exhibiting a certain degree of universality. It can achieve direct decomposition of H2S at room temperature using only light irradiation, and its activity and stability are at least 2-3 times higher than the currently optimal Au / SiO2 catalyst. Specifically, when H2S gas is introduced at a wavelength of 450 nm and a power density of 13.7 W / cm²,… 2 Under light irradiation, the hydrogen production rate can reach 49148 μmol·g -1 ·h -1 And at a higher optical power density (11.7 W / cm²), 2 Even after 180 minutes of continuous reaction, the hydrogen production rate remained above 86%, indicating that the supported CdS / Mo2CT x The catalytic efficiency and stability of this photocatalyst are significantly higher than those of similar catalysts. In other words, this invention can effectively utilize renewable light energy to decompose highly toxic and corrosive H2S, providing new ideas for the synthesis and application of related supported photocatalysts. Attached Figure Description

[0026] Figure 1 In Embodiment 1 of this invention, the molybdenum gallium carbide MAX phase (Ma2Ga2C) is a multilayer molybdenum carbide (M-Mo2CT) formed after the Ga layer is etched. x ) and few-layer molybdenum carbide nanosheets (F-Mo2CT) x X-ray diffraction (XRD) pattern of )

[0027] Figure 2 This is a transmission electron microscope (TEM) image of cadmium sulfide (CdS), a semiconductor material, in Example 2 of the present invention.

[0028] Figure 3 This is a TEM image of the supported photocatalyst CM-6 in Example 3 of the present invention;

[0029] Figure 4 The hydrogen production rate of the supported photocatalyst CM-6 in this invention under different light power densities under 450nm light illumination is shown in the figure.

[0030] Figure 5 The supported photocatalyst CM-6 in this invention operates at a wavelength of 450 nm and a power density of 11.7 W / cm².2 A graph showing the rate of hydrogen production under continuous illumination;

[0031] Figure 6 This is a schematic diagram of the quartz reactor in this invention. Detailed Implementation

[0032] The present invention will be further described in detail below through embodiments, but these embodiments should not be considered as limiting the present invention.

[0033] Example 1:

[0034] A method for preparing a support in a supported photocatalyst, this embodiment using the two-dimensional plasmon material few-layer molybdenum carbide (F-Mo2CT) described in this invention. x The method for preparing the MXene vector includes the following steps:

[0035] Step 1: Measure 20 mL of 6M hydrochloric acid into a 50 mL polytetrafluoroethylene (PTFE) liner, then weigh 1 g of NH4F and add it to the PTFE liner. Stir at room temperature for 0.5 h, then weigh 1 g of molybdenum gallium carbide (Ma2Ga2C) and slowly add it to the mixture while stirring. Continue stirring at room temperature for 0.5 h, then place the PTFE liner into a high-pressure reactor and tighten it. Then react at 180 °C for 24 h in a reaction oven.

[0036] Step 2: After the reaction vessel described in Step 1 has cooled to room temperature, the resulting precipitate is dispersed in ultrapure water and centrifuged at 5000 rpm for 5 min. This centrifugation process is repeated 5-8 times until the supernatant is maintained at near neutral. The lower precipitate is then dispersed in ethanol and centrifuged at 5000 rpm for 5 min. The resulting precipitate is dried in a vacuum oven at 45°C for 24 h. After grinding the solid, multilayer molybdenum carbide powder is obtained, which is named M-Mo2CT. x ;

[0037] Step 3: Measure 15 ml of a 25% (w / w) aqueous solution of tetramethylammonium hydroxide (TMAOH) into a 100 ml Shrek bottle, then weigh 200 mg of the M-Mo2CT prepared in Step 2. x Add to the bottle, introduce argon gas, and stir at room temperature for 24 hours;

[0038] Step 4: Centrifuge with ultrapure water and ethanol at 9000 rpm 2-3 times each until the pH of the supernatant is between 6 and 7. Then, further disperse the lower precipitate with water and sonicate in an ice bath for 10-20 min, followed by centrifugation at 10000 rpm for 8 min. The obtained supernatant is the dispersion of few-layer molybdenum carbide nanosheets. Repeat the ice bath sonication and centrifugation process 6-7 times. Collect the supernatant dispersion after multiple centrifugations into a flask and freeze-dry it. The resulting fluffy solid is the few-layer molybdenum carbide nanosheet, named F-Mo2CT. x .

[0039] Figure 1 In Embodiment 1 of this invention, the molybdenum gallium carbide MAX phase (Ma2Ga2C) is a multilayer molybdenum carbide (M-Mo2CT) formed after the Ga layer is etched. x ) and few-layer molybdenum carbide nanosheets (F-Mo2CT) x The XRD pattern of Ma2Ga2C shows that after etching, the strongest characteristic peak (2θ = 40.07°) disappears, and the diffraction peak corresponding to its (002) crystal plane broadens and shifts to a lower angle, from the original 9.82° to 8.47° (lattice parameter c changes from 002° to 40.07°). Increase to This result indicates that lattice expansion and increased interplanar spacing occurred, confirming the successful etching of the Ga layer in Ma2Ga2C; multilayer molybdenum carbide (M-Mo2CT) x After intercalation, it can be observed that the diffraction peak corresponding to its (002) crystal plane is further shifted to a lower angle, from 8.47° to 7.25° (lattice parameter c from...). Increase to This further illustrates that few-layer molybdenum carbide nanosheets (F-Mo2CT) with larger interlayer spacing were ultimately formed. x ).

[0040] Example 2:

[0041] A method for preparing catalytically active materials in supported photocatalysts, this embodiment being a method for preparing cadmium sulfide (CdS), the semiconductor material described in this invention:

[0042] Weigh 1.15g of cadmium nitrate tetrahydrate into a 100ml Shrek bottle and add 30mL of ultrapure water. Then sonicate for 20min, add 1.3mL of ammonium sulfide solution dropwise, and stir with argon gas for 1h. Centrifuge with water and ethanol at 8000rpm for 5min. Repeat this centrifugation process 3 times. Dry the lower precipitate in a vacuum oven at 45℃ for 24h. After grinding, obtain CdS powder.

[0043] Figure 2The image shows a transmission electron microscope (TEM) image of cadmium sulfide (CdS), a semiconductor material, in Example 2 of this invention. The image shows that the average particle size of the CdS nanoparticles is about 10.4 nm. Smaller CdS particles are more conducive to subsequent loading and catalytic reactions.

[0044] Example 3:

[0045] A method for preparing a supported photocatalyst, this embodiment being the method for preparing the supported photocatalyst CM-6 described in this invention:

[0046] Weigh 32.3 mg of F-Mo2CT prepared in Example 1. x After dissolving in 20 mL of ultrapure water, the solution was poured into a 100 mL Shrek flask and purged with argon gas. After sonication for 0.5 h, dispersion A was prepared. Then, 1.15 g of cadmium nitrate tetrahydrate was dissolved in 10 mL of water and sonicated for 20 min to prepare solution B. Solution B was added dropwise to dispersion A while stirring, and argon gas was continued to be purged and sonicated for 0.5 h. Then, 1.3 mL of ammonium sulfide solution was added dropwise, and argon gas was continued to be purged and stirred for another 1 h. The mixture was then centrifuged with water and ethanol at 8000 rpm for 5 min, and this centrifugation process was repeated three times. The lower precipitate was then dried in a vacuum oven at 45 °C for 24 h, and finally ground to obtain CdS / Mo2CT. x The catalyst was named CM-6.

[0047] Figure 3 This is a TEM image of the supported photocatalyst CM-6 in Example 3 of the present invention. The image shows that CdS nanoparticles were successfully loaded onto F-Mo2CT. x superior.

[0048] Example 4:

[0049] An application of a supported photocatalyst, this embodiment shows the application effect of the supported photocatalyst CM-6 in the direct photocatalytic decomposition of H2S.

[0050] In this embodiment, the H2S gas was purchased from Jining Xieli Special Gases Co., Ltd., the quartz reactor was customized from Donghai County Donghua Quartz Products Co., Ltd., the laser was purchased from Changchun New Industries Optoelectronic Technology Co., Ltd., and the gas chromatograph for detecting H2 was Nexis GC-2030.

[0051] The supported photocatalyst CM-6 prepared in Example 3 was used for the photocatalytic direct decomposition of H2S. The catalyst loading was 5 mg, the H2S flow rate was 10 SCCM (standard cubic centimeters per minute), the reaction was carried out under normal pressure, the laser wavelength was 450 nm, and the optical power density was 4.2 W / cm². 2 5.6W / cm 27.0W / cm 2 8.3W / cm 2 9.6W / cm 2 11.0W / cm 2 12.3W / cm 2 13.7W / cm 2 The spot size is 2.54 mm.

[0052] Figure 4 This graph shows the hydrogen production rate of the supported photocatalyst CM-6 in this invention under different light power densities at a wavelength of 450 nm. As can be seen from the graph, the hydrogen production rate increases with increasing power density, reaching a maximum at a power density of 13.7 W / cm². 2 At that time, the hydrogen production rate reached as high as 49148 μmol·g. -1 ·h -1 .

[0053] Example 5:

[0054] This embodiment is a stability analysis of the supported photocatalyst CM-6 for the direct photocatalytic decomposition of H2S.

[0055] The supported photocatalyst CM-6 prepared in Example 3 was used for the direct photocatalytic decomposition of H2S under continuous illumination. The catalyst loading was 5 mg, the H2S flow rate was 10 SCCM, the reaction was carried out at atmospheric pressure, the laser wavelength was 450 nm, and the power density was 11.7 W / cm². 2 The spot size is 2.54 mm.

[0056] Figure 5 The supported photocatalyst CM-6 in this invention operates at a laser wavelength of 450 nm and a power density of 11.7 W / cm². 2 The graph shows the change in hydrogen production rate under continuous illumination. As can be seen from the graph, after 180 minutes of continuous illumination at high power density, the catalytic activity of the catalyst remains above 86%, indicating its high stability.

[0057] Comparative Example 1:

[0058] This comparative example is the two-dimensional plasmonic material F-Mo2CT. x The application effect of the carrier in the direct photocatalytic decomposition of H2S.

[0059] The F-Mo2CT prepared in Example 1 x The support was used for the photocatalytic direct decomposition of H2S. The loading amount of the support was 5 mg, the H2S flow rate was 10 SCCM, the reaction was carried out at atmospheric pressure, the laser wavelength was 577 nm, and the power density was 10.9 W / cm².2 The spot size was 2.00 mm. The experimental results are shown in Table 1. The H2 production rate was 1144 μmol·g⁻¹. -1 ·h -1 .

[0060] Comparative Example 2:

[0061] This comparative example demonstrates the application effect of the semiconductor material CdS in the photocatalytic direct decomposition of H2S.

[0062] The CdS semiconductor material prepared in Example 2 was used for the photocatalytic direct decomposition of H2S. The material loading was 5 mg, the H2S flow rate was 10 SCCM, the reaction was carried out under normal pressure, the laser wavelength was 577 nm, and the power density was 10.9 W / cm². 2 The spot size was 2.00 mm. The experimental results are shown in Table 1. The H2 production rate was 878 μmol·g⁻¹. -1 ·h -1 .

[0063] Comparative Example 3:

[0064] This comparative example demonstrates the application effect of the supported photocatalyst CM-6 in the direct photocatalytic decomposition of H2S.

[0065] The supported photocatalyst CM-6 prepared in Example 3 was used for the photocatalytic direct decomposition of H2S. The catalyst loading was 5 mg, the H2S flow rate was 10 SCCM, the reaction was carried out at atmospheric pressure, the laser wavelength was 577 nm, and the power density was 10.9 W / cm². 2 The spot size was 2.00 mm. The experimental results are shown in Table 1. The H2 production rate was 9971 μmol·g⁻¹. -1 ·h -1 .

[0066] Table 1: H2 production rates of Comparative Examples 1, 2, and 3:

[0067]

[0068] Based on the results of the above embodiments and comparative examples, the supported photocatalyst prepared by the present invention utilizes CdS and F-Mo2CT. x The synergistic effect between them resulted in superior performance, with the photocatalytic decomposition of H2S being far more effective than that of CdS and F-Mo2CT. x Its individual function.

[0069] In summary, the loaded CdS / Mo2CT described in this invention xPhotocatalysts are well-suited for synergistic action with light, enabling the direct decomposition of H2S under light irradiation alone, thus promoting the rational utilization of resources. Under optimal conditions (laser wavelength 450 nm, power density 13.7 W / cm²), [the decomposition was achieved]. 2 The hydrogen production rate reached as high as 49148 μmol·g. -1 ·h -1 Meanwhile, the catalyst operates at a high light power density (11.7 W / cm²). 2 Even under continuous irradiation (180 min), the catalyst maintains high catalytic activity (over 86%), broadening its application scenarios. Therefore, this invention has significant potential for application and will contribute to further research and development in the field of H2S decomposition and utilization.

[0070] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. Various process solutions that are not substantially different from the concept of the present invention are all within the scope of protection of the present invention.

Claims

1. The application of a supported photocatalyst in the direct photocatalytic decomposition of hydrogen sulfide, characterized in that: The supported photocatalyst is filled into a specially designed quartz reactor to form a micro-reaction bed. After pure H2S gas is introduced, H2S is decomposed into hydrogen and sulfur under laser irradiation. The preparation method of the supported photocatalyst includes the following steps: Step A: The precursor Mo2Ga2CMAX phase was etched using a hydrothermal method to obtain multilayered molybdenum carbide, which was named M-Mo2CT. x Then, after centrifugation with water and ethanol respectively, vacuum drying was performed, followed by grinding to obtain powder. Step B: Using a 25% (w / w) aqueous solution of tetramethylammonium hydroxide as an intercalating agent for M-Mo2CT x Intercalation was performed to obtain a few layers of molybdenum carbide, which was named F-Mo2CT. x The supernatant dispersion was accumulated through repeated ice bath sonication and centrifugation, and then freeze-dried to obtain fluffy F-Mo2CT. x solid; Step C: The F-Mo2CT obtained in the previous step... x After the solid was redispersed in ultrapure water, cadmium nitrate tetrahydrate was added dropwise as a cadmium source. After ultrasonic treatment, an aqueous solution of ammonium sulfide with a mass fraction of 20-26% was added dropwise as a sulfur source. Then, the mixture was centrifuged with water and ethanol respectively, vacuum dried, and ground to obtain CdS / Mo2CT. x Solid photocatalyst, i.e., the supported photocatalyst; The supported photocatalyst includes the two-dimensional plasmonic material few-layer molybdenum carbide (F-Mo2CT). x MXene and cadmium sulfide (CdS) and F-Mo2CT semiconductor materials loaded on its surface x Prepared by etching, intercalation, and stripping of the precursor Mo2Ga2C, CdS is loaded onto F-Mo2CT via precipitation. x The resulting composite material is CdS / Mo2CT. x Photocatalyst.

2. The application of the supported photocatalyst according to claim 1 in the photocatalytic direct decomposition of hydrogen sulfide, characterized in that: In steps A through C, all reactions occur in a Shrek flask, and argon gas is required during the reaction to prevent the materials from being oxidized.

3. The application of the supported photocatalyst according to claim 1 in the photocatalytic direct decomposition of hydrogen sulfide, characterized in that: The etching of the precursor Mo2Ga2C MAX phase by hydrothermal method described in step A is carried out according to the following ratio: the amount of precursor Mo2Ga2C is 1-2 g, and a mixed solution of 1-2 g NH4F and 20-40 ml 6 M HCl is used as the etching solution. The etching is carried out in a high-pressure reactor at 180°C for 24 h. The precursor Mo2Ga2C needs to be added to the etching solution slowly to prevent violent reaction.

4. The application of the supported photocatalyst according to claim 1 in the photocatalytic direct decomposition of hydrogen sulfide, characterized in that: Step B describes the use of a 25% (w / w) aqueous solution of tetramethylammonium hydroxide as an intercalating agent for M-Mo2CT. x Intercalation is performed according to the following ratio, M-Mo2CT x The dosage is 200-400 mg, which is added to 15-30 ml of a 25% tetramethylammonium hydroxide aqueous solution, and then stirred at room temperature for 16-24 h.

5. The application of the supported photocatalyst according to claim 1 in the photocatalytic direct decomposition of hydrogen sulfide, characterized in that: In step C, the following proportions are used: 1.15 g of cadmium nitrate tetrahydrate is dissolved in 10 ml of ultrapure water; 1.3 ml of ammonium sulfide solution is used; and F-Mo2CT... x The dosage was 10.8-64.6 mg, dispersed in 20 ml of ultrapure water; simultaneously, according to CdS / Mo2CT... x F-Mo2CT in solid photocatalysts x The CdS mass fractions of 1.5%, 2.5%, 4%, 5%, 6%, 7%, 8%, and 12% are respectively named CM-1.5, CM-2.5, CM-4, CM-5, CM-6, CM-7, CM-8, and CM-12.

6. The application of the supported photocatalyst according to claim 1 in the photocatalytic direct decomposition of hydrogen sulfide, characterized in that: When filling the supported photocatalyst, 2 mm thick quartz wool needs to be filled into the thin tube of the specially made quartz reactor near the tube opening first, then 5 mg of catalyst is added, and then a solid aluminum rod is used to compact it into the quartz wool to form a micro gas-solid phase reaction bed.

7. The application of the supported photocatalyst according to claim 1 in the photocatalytic direct decomposition of hydrogen sulfide, characterized in that: Before introducing pure H2S gas, the pipeline needs to be leak-tested with inert gas to ensure that the pipeline is properly sealed.

8. The application of the supported photocatalyst according to claim 1 in the photocatalytic direct decomposition of hydrogen sulfide, characterized in that: The reaction is carried out under laser irradiation, with laser wavelengths of 405 nm, 450 nm, 470 nm, 520 nm, 577 nm, 637 nm, and 677 nm; the spot size is 2.00-2.54 mm; and the optical power density is 4.2-13.7 W / cm². 2 .

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