Photocatalyst based on sulfide homogeneous heterojunction and preparation method and application thereof

Abstract

The invention provides a photocatalyst based on sulfide homogeneous heterojunction and a preparation method and application thereof, and belongs to the technical field of photocatalysts. The photocatalyst based on the sulfide homogeneous heterojunction provided by the invention is a heterojunction formed by twin-crystal sulfur-cadmium-manganese and transition metal sulfide, has excellent structural stability, and can provide more photo-induced electrons. Therefore, when the photocatalyst provided by the invention is used for degrading H2S to produce hydrogen, the Schottky junction of the photocatalyst can reduce the hydrogen production overpotential, H2S is effectively decomposed to produce hydrogen, and meanwhile, a product Na2S2O3 with a high additional value is produced. The result of the embodiment shows that the photocatalyst based on the sulfide homogeneous heterojunction has excellent catalytic activity when being used for degrading H2S to produce hydrogen.

Description

Technical Field

[0001] The present invention relates to the technical field of photocatalysts, and in particular to a photocatalyst based on a sulfide homogeneous heterojunction, a preparation method thereof, and applications thereof. Background Art

[0002] Large amounts of H2S are generated in processes such as natural gas extraction, petroleum refining, wastewater treatment, and the papermaking industry, posing significant risks to human health and the environment. Currently, the most commonly used H2S treatment technology in industry is the Claus process, which converts H2S into elemental sulfur and water, achieving resource utilization and meeting environmental standards. However, the hydrogen atoms in this process are converted into water as a product, and hydrogen resources are not recovered, resulting in a waste of resources. Furthermore, this process can only treat high-concentration H2S and cannot convert low-concentration H2S.

[0003] Photocatalytic decomposition of H2S involves converting H2S into hydrogen energy (H2) and high-value sulfur under the action of a photocatalyst. Research on catalysts for photocatalytic H2S decomposition has been ongoing, including a related art publication that discloses an In2S3 / CuS nanosheet composite photocatalyst that can utilize solar energy to convert hydrogen atoms in H2S into H2. However, the preparation method for this photocatalyst is complex; it also lacks sufficient visible light utilization and has a rapid recombination rate for photogenerated electron-hole pairs, resulting in low H2S decomposition efficiency.

[0004] Therefore, there is an urgent need to provide a catalyst with high photocatalytic activity for photocatalytic decomposition of H2S. Summary of the Invention

[0005] The purpose of the present invention is to provide a photocatalyst with high photocatalytic activity for photocatalytic decomposition of H2S, as well as a preparation method and application thereof.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a sulfide heterojunction-based photocatalyst, wherein the sulfide heterojunction-based photocatalyst is a heterojunction formed by twinned cadmium manganese sulfate and transition metal sulfide;

[0008] Calculated by mass percentage, the sulfide heterojunction-based photocatalyst comprises 88-96 wt % of twinned cadmium manganese sulfide and 4-12 wt % of transition metal sulfide.

[0009] Preferably, the transition metal sulfide includes one or more of NiS, NiS2, Ni3S4 and CuS.

[0010] The present invention also provides a method for preparing the sulfide heterojunction-based photocatalyst described in the above technical solution, comprising the following steps:

[0011] (1) mixing a soluble manganese source, a soluble cadmium source, a soluble sulfur source, an alkaline regulator, and water to obtain an alkaline raw material solution, and subjecting the alkaline raw material solution to a hydrothermal reaction to obtain twinned sulfur-cadmium manganese;

[0012] The molar ratio of the manganese element in the soluble manganese source, the cadmium element in the soluble cadmium source, and the sulfur element in the soluble sulfur source is (0.25-2): (0.25-2): (4-6);

[0013] (2) mixing a soluble transition metal salt, a soluble sulfur source, and a solvent, and performing a solvothermal reaction to obtain a transition metal sulfide;

[0014] (3) The twinned manganese cadmium sulfide obtained in step (1), the transition metal sulfide obtained in step (2) and a dispersing solvent are mixed and subjected to interfacial self-assembly to obtain a photocatalyst based on a sulfide homogeneous heterojunction; the mass ratio of the twinned manganese cadmium sulfide to the transition metal sulfide is (88-96): (4-12).

[0015] Preferably, the soluble manganese source in step (1) includes one or more of manganese chloride, manganese nitrate and manganese acetate; the soluble cadmium source includes one or more of cadmium chloride, cadmium nitrate and cadmium acetate; and the soluble sulfur source is C2H5NS or CH4N2S.

[0016] Preferably, the pH value of the alkaline raw material solution in step (1) is 13-14.

[0017] Preferably, the temperature of the hydrothermal reaction in step (1) is 180-200° C.; and the time of the hydrothermal reaction is 6-24 hours.

[0018] Preferably, the soluble transition metal salt in step (2) includes a soluble nickel salt or a soluble copper salt; and the soluble sulfur source includes C2H5NS or CH4N2S.

[0019] Preferably, the temperature of the solvent thermal reaction in step (2) is 140 to 200° C.; and the time of the solvent thermal reaction is 12 to 24 hours.

[0020] Preferably, the temperature of the interface self-assembly in step (3) is 60-70° C.; and the time of the interface self-assembly is 1-3 hours.

[0021] The present invention also provides the use of the sulfide heterojunction-based photocatalyst described in the above technical solution or the sulfide heterojunction-based photocatalyst prepared by the preparation method described in the above technical solution as a photocatalyst for degrading H2S to produce hydrogen.

[0022] The present invention provides a sulfide heterojunction-based photocatalyst, comprising a heterojunction formed by twinned manganese cadmium sulfide (MCS) and a transition metal sulfide. The sulfide heterojunction-based photocatalyst comprises, by mass percentage, 88-96% of the twinned manganese cadmium sulfide (MCS) and 4-12% of the transition metal sulfide. The sulfide heterojunction-based photocatalyst provided by the present invention, comprising a heterojunction formed by twinned manganese cadmium sulfide (MCS) and a transition metal sulfide, exhibits excellent structural stability and can provide more photogenerated electrons. Therefore, when the sulfide heterojunction-based photocatalyst provided by the present invention is used for photocatalytic degradation of H2S to produce hydrogen, the Schottky junction of the photocatalyst can reduce the hydrogen production overpotential, effectively decomposing H2S to produce hydrogen, and simultaneously producing the high-value-added product Na2S2O3. Example results demonstrate that the sulfide heterojunction-based photocatalyst provided by the present invention exhibits excellent photocatalytic activity when used for degradation of H2S to produce hydrogen. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the device for use in the hydrogen production by degradation of H2S using a sulfide heterojunction-based photocatalyst provided by the present invention;

[0024] Figure 2 This is a diagram showing the mechanism of the sulfide heterojunction-based photocatalyst provided by the present invention for degrading H2S to produce hydrogen;

[0025] Figure 3 XRD patterns of T-MCS prepared in Example 1 of the present invention, WZ-MCS prepared in Comparative Example 5, and ZB-MCS prepared in Comparative Example 6;

[0026] Figure 4 TEM image of T-MCS prepared in Example 1 of the present invention;

[0027] Figure 5 XRD patterns of T-MCS prepared in Example 1 of the present invention, NiS2 prepared in Example 6, and 8wt% NiS2 / T-MCS;

[0028] Figure 6 TEM image of 8wt% NiS2 / T-MCS prepared in Example 6 of the present invention;

[0029] Figure 7 The sulfide heterojunction-based photocatalysts prepared in Examples 1 to 3 and 6 of the present invention, the CuS prepared in Comparative Example 4, the T-MCS prepared in Example 1, the WZ-MCS prepared in Comparative Example 5, and the ZB-MCS prepared in Comparative Example 6 were tested for catalytic hydrogen production, and the hydrogen production rate graphs obtained were obtained;

[0030] Figure 8Graph showing the hydrogen production rate of the sulfide heterojunction-based photocatalysts prepared in Examples 4 to 8 of the present invention;

[0031] Figure 9 (a) is the infrared spectra of 0.1M Na2S / 0.6M Na2SO3 solution before and after absorbing H2S; (b) is the infrared spectra of different photocatalysts after reacting in 0.1M Na2S / 0.6M Na2SO3 solution that has absorbed H2S. DETAILED DESCRIPTION

[0032] The present invention provides a sulfide heterojunction-based photocatalyst, wherein the sulfide heterojunction-based photocatalyst is a heterojunction formed by twinned cadmium manganese sulfate and transition metal sulfide;

[0033] Calculated by mass percentage, the sulfide heterojunction-based photocatalyst comprises 88-96 wt % of twinned cadmium manganese sulfide and 4-12 wt % of transition metal sulfide.

[0034] The photocatalyst based on sulfide homogeneous heterojunction provided by the present invention is a heterojunction formed by twin crystals of cadmium manganese sulfide and transition metal sulfide.

[0035] In terms of mass percentage, the sulfide heterojunction-based photocatalyst comprises 88-96 wt% of twinned cadmium manganese sulfide. As one embodiment of the present invention, the mass percentage of the twinned cadmium manganese sulfide can be 88 wt%, 89 wt%, 90 wt%, 91 wt%, 92 wt%, 93 wt%, 94 wt%, 95 wt%, or 96 wt%. The sulfide heterojunction-based photocatalyst provided by the present invention is twinned cadmium manganese sulfide. The twinned homojunction can provide more photogenerated electrons, and the Schottky junction can reduce the overpotential of hydrogen production, thereby effectively decomposing H2S and simultaneously producing the high-value-added product Na2S2O3.

[0036] In the present invention, the particle size of the twinned manganese cadmium sulfur is preferably 20 to 120 nm, more preferably 50 to 100 nm. The particle size of the twinned manganese cadmium sulfur provided by the present invention is within the above range, which is more conducive to improving the photocatalytic activity of the catalyst.

[0037] The sulfide heterojunction-based photocatalyst comprises 4 to 12 wt% of a transition metal sulfide, measured by mass percentage. As one embodiment of the present invention, the transition metal sulfide can comprise 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, or 12 wt%. In the present invention, the transition metal sulfide preferably comprises one or more of NiS, NiS2, Ni3S4, and CuS. The present invention utilizes these transition metal sulfides to enhance the photocatalytic activity of the sulfide heterojunction-based photocatalyst.

[0038] In the present invention, the particle size of the transition metal sulfide is preferably 10 to 300 nm, more preferably 20 to 150 nm. Controlling the particle size of the transition metal sulfide within the above range is more conducive to interacting with the twinned cadmium manganese sulfide to form a heterojunction.

[0039] The present invention also provides a method for preparing the sulfide heterojunction-based photocatalyst described in the above technical solution, comprising the following steps:

[0040] (1) mixing a soluble manganese source, a soluble cadmium source, a soluble sulfur source, an alkaline regulator, and water to obtain an alkaline raw material solution, and subjecting the alkaline raw material solution to a hydrothermal reaction to obtain twinned sulfur-cadmium manganese;

[0041] The molar ratio of the manganese element in the soluble manganese source, the cadmium element in the soluble cadmium source, and the sulfur element in the soluble sulfur source is (0.25-2): (0.25-2): (4-6);

[0042] (2) mixing a soluble transition metal salt, a soluble sulfur source, and a solvent, and performing a solvothermal reaction to obtain a transition metal sulfide;

[0043] (3) The twinned manganese cadmium sulfide obtained in step (1), the transition metal sulfide obtained in step (2) and a dispersing solvent are mixed and subjected to interfacial self-assembly to obtain a photocatalyst based on a sulfide homogeneous heterojunction; the mass ratio of the twinned manganese cadmium sulfide to the transition metal sulfide is (88-96): (4-12).

[0044] The invention comprises the following steps: mixing a soluble manganese source, a soluble cadmium source, a soluble sulfur source, an alkaline regulator and water to obtain an alkaline raw material liquid; and subjecting the alkaline raw material liquid to a hydrothermal reaction to obtain twinned sulfur-cadmium manganese.

[0045] In the present invention, the soluble manganese source preferably includes one or more of manganese chloride, manganese nitrate and manganese acetate, more preferably manganese chloride, manganese nitrate or manganese acetate.

[0046] In the present invention, the soluble cadmium source preferably includes one or more of cadmium chloride, cadmium nitrate and cadmium acetate, more preferably cadmium chloride, cadmium nitrate or cadmium acetate.

[0047] In the present invention, the soluble sulfur source is preferably C2H5NS or CH4N2S.

[0048] In the present invention, the molar ratio of manganese in the soluble manganese source, cadmium in the soluble cadmium source, and sulfur in the soluble sulfur source is preferably (0.25-2):(0.25-2):(4-6), and more preferably 1:1:4. By controlling the molar ratio of manganese in the soluble manganese source, cadmium in the soluble cadmium source, and sulfur in the soluble sulfur source within the above range, the present invention can produce twinned sulfur-cadmium manganese with high purity.

[0049] In the present invention, the alkaline regulator is preferably an aqueous NaOH solution. In the present invention, the concentration of the aqueous NaOH solution is preferably 1 to 10 mol / L. As one embodiment of the present invention, the concentration of the aqueous NaOH solution can be 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, or 10 mol / L. The use of the aqueous NaOH solution in the present invention can adjust the pH value of the alkaline raw material solution to the desired range.

[0050] In the present invention, the pH value of the alkaline raw material liquid is preferably 13 to 14. As an embodiment of the present invention, the pH value of the alkaline raw material liquid can be 13, 13.5 or 14. The present invention controls the pH value of the alkaline raw material liquid within the above range to provide a suitable alkaline environment, which is more conducive to the formation of twinned cadmium manganese sulfate during the hydrothermal reaction.

[0051] The present invention has no particular limitation on the amount of NaOH aqueous solution used, and the pH of the alkaline raw material solution can be adjusted to 13-14.

[0052] In the present invention, the water is preferably deionized water. The present invention utilizes water as a solvent for the hydrothermal reaction.

[0053] In the present invention, the ratio of the amount of manganese in the soluble manganese source, the amount of cadmium in the soluble cadmium source, and the volume of water is preferably (0.25-2) mol: (0.25-2) mol: (40-60) L, and more preferably 1 mol: 1 mol: 60 L. By controlling the ratio of the amount of manganese in the soluble manganese source, the amount of cadmium in the soluble cadmium source, and the volume of water within the above range, the alkaline raw material solution can have an appropriate concentration, which is more conducive to a more complete hydrothermal reaction and the production of high-purity twinned sulfur-cadmium manganese.

[0054] In the present invention, the temperature of the hydrothermal reaction is preferably 180-200°C, more preferably 180°C; the time of the hydrothermal reaction is 6-24h, more preferably 12-18h. The present invention can make the hydrothermal reaction more complete at the above temperature and time to obtain high-purity twinned manganese cadmium sulfur. The present invention has no special limitation on the device for the hydrothermal reaction, and any conventional hydrothermal reaction device can be used. In an embodiment of the present invention, the device for the hydrothermal reaction can be a hydrothermal synthesis reaction tank equipped with an inner lining, and the material of the inner lining in the hydrothermal synthesis reaction tank can be polytetrafluoroethylene.

[0055] The present invention preferably filters the system obtained by the hydrothermal reaction, and then sequentially washes and dries the solids obtained by filtration to obtain twinned manganese cadmium sulfide. The present invention does not specifically limit the filtering method, and a conventional filtering method can be used to separate the solids in the system obtained by the hydrothermal reaction. In an embodiment of the present invention, the washing reagent can be water, and the washing method can be water washing and centrifugation. In an embodiment of the present invention, the drying temperature is preferably 60 to 70°C, more preferably 60 to 68°C; the drying time is preferably 6 to 10 hours, more preferably 7 to 9 hours.

[0056] The invention mixes a soluble transition metal salt, a soluble sulfur source and a solvent, and performs a solvent thermal reaction to obtain a transition metal sulfide.

[0057] In the present invention, the soluble transition metal salt preferably includes a soluble nickel salt or a soluble copper salt. In the present invention, the soluble nickel salt is preferably nickel chloride, nickel nitrate or nickel acetate. In the present invention, the soluble copper salt is preferably copper chloride, copper nitrate or copper acetate.

[0058] In the present invention, the soluble sulfur source includes C2H5NS or CH4N2S.

[0059] In the present invention, the solvent is preferably anhydrous ethanol or water. The present invention has no particular limitation on the amount of the solvent, as long as it can completely dissolve the soluble transition metal salt and the soluble sulfur source.

[0060] In the present invention, the molar ratio of the nickel element in the soluble nickel salt to the sulfur element in the soluble sulfur source is preferably 1: (1 to 1.5), more preferably 1: (1 to 1.2), and the transition metal sulfide is NiS. In the present invention, the solvent is preferably anhydrous ethanol. In the present invention, the temperature of the solvent thermal reaction is preferably 180 to 200°C. As an embodiment of the present invention, the temperature of the solvent thermal reaction may be 180°C, 190°C or 200°C. In the present invention, the time of the solvent thermal reaction is preferably 12 to 24h. As an embodiment of the present invention, the time of the solvent thermal reaction may be 12h, 16h, 18h, 20h, 22h or 24h. The present invention can obtain NiS at the above-mentioned solvent thermal reaction temperature and time. In the present invention, the equation of the solvent thermal reaction is preferably: Ni 2+ +S 2- →NiS.

[0061] In the present invention, the molar ratio of the nickel element in the soluble nickel salt to the sulfur element in the soluble sulfur source is preferably 1:(4-5), more preferably 1:4, and the transition metal sulfide is NiS2. In the present invention, the solvent is preferably anhydrous ethanol. In the present invention, the temperature of the solvent thermal reaction is preferably 160-180°C. As an embodiment of the present invention, the temperature of the solvent thermal reaction may be 160°C, 170°C or 18°C. In the present invention, the time of the solvent thermal reaction is preferably 16-18h. As an embodiment of the present invention, the time of the solvent thermal reaction may be 16h, 17h or 18h. The present invention can obtain NiS2 at the above-mentioned solvent thermal reaction temperature and time.

[0062] In the present invention, the molar ratio of the nickel element in the soluble nickel salt to the sulfur element in the soluble sulfur source is preferably 1:(1.5-2), more preferably 1:1.5, and the transition metal sulfide is Ni3S4. In the present invention, the solvent is preferably water. In the present invention, the temperature of the solvothermal reaction is preferably 140-160°C. As an embodiment of the present invention, the temperature of the solvothermal reaction may be 140°C, 150°C or 160°C. In the present invention, the time of the solvothermal reaction is preferably 18-20h. As an embodiment of the present invention, the time of the solvothermal reaction may be 18h, 19h or 20h. The present invention can obtain Ni3S4 at the above-mentioned solvothermal reaction temperature and time.

[0063] In the present invention, the molar ratio of the copper element in the soluble copper salt to the sulfur element in the soluble sulfur source is preferably 1:(4-6), more preferably 1:4, and the transition metal sulfide is CuS. In the present invention, the solvent is preferably water. In the present invention, the temperature of the solvent thermal reaction is preferably 160-180°C. As an embodiment of the present invention, the temperature of the solvent thermal reaction may be 160°C, 170°C or 180°C. In the present invention, the time of the solvent thermal reaction is preferably 18-24h. As an embodiment of the present invention, the time of the solvent thermal reaction may be 18h, 20h, 22h or 24h. The present invention can obtain CuS at the above-mentioned solvent thermal reaction temperature and time. In an embodiment of the present invention, the equation of the solvent thermal reaction is preferably Cu 2+ +S 2- →CuS.

[0064] The present invention preferably filters the system obtained by the solvent thermal reaction, and then washes and dries the solid obtained by filtration in sequence to obtain a transition metal sulfide. The present invention does not specifically limit the filtering method, and a conventional filtering method can be used to separate the solids in the system obtained by the solvent thermal reaction. In an embodiment of the present invention, the washing reagent can be water, and the washing method can be water washing and centrifugation. In an embodiment of the present invention, the drying temperature is preferably 60 to 70°C, more preferably 60 to 68°C; the drying time is preferably 6 to 10 hours, more preferably 7 to 9 hours.

[0065] After obtaining twinned manganese cadmium sulfur and transition metal sulfide, the present invention mixes the twinned manganese cadmium sulfur, transition metal sulfide and a dispersing solvent, performs interface self-assembly, and obtains a photocatalyst based on sulfide homogeneous heterojunction.

[0066] In the present invention, the mass ratio of the twinned manganese cadmium sulfur to the transition metal sulfide is (88-96):(4-12). As one embodiment of the present invention, the mass ratio of the twinned manganese cadmium sulfur to the transition metal sulfide can be 88:12, 89:11, 90:10, 91:9, 92:8, 93:7, 94:6, 95:5, or 96:4. By controlling the mass ratio of the twinned manganese cadmium sulfur to the transition metal sulfide within the above range, the present invention can improve the catalytic activity of the photocatalyst.

[0067] In the present invention, the dispersion solvent preferably includes ethanol.

[0068] In the present invention, the method of mixing the twinned manganese cadmium sulfur, transition metal sulfide and dispersion solvent is preferably: mixing the twinned manganese cadmium sulfur with the dispersion solvent to obtain a twinned manganese cadmium sulfur dispersion; mixing the transition metal sulfide with the dispersion solvent to obtain a transition metal sulfide dispersion; and mixing the twinned manganese cadmium sulfur dispersion with the transition metal sulfide dispersion.

[0069] In the present invention, the ratio of the mass of the twinned manganese cadmium sulfide to the volume of the dispersion solvent in the twinned manganese cadmium sulfide dispersion is preferably (88-96) g:10 L. As an embodiment of the present invention, the ratio of the mass of the twinned manganese cadmium sulfide to the volume of the dispersion solvent in the twinned manganese cadmium sulfide dispersion may be 88 g:10 L, 89 g:10 L, 90 g:10 L, 91 g:10 L, 92 g:10 L, 93 g:10 L, 94 g:10 L, 95 g:10 L, or 96 g:10 L.

[0070] In the present invention, the method for mixing the twinned manganese cadmium sulfide and the dispersion solvent is preferably ultrasound. The present invention has no particular limitation on the power and time of the ultrasound, as long as the twinned manganese cadmium sulfide and the dispersion solvent are uniformly dispersed.

[0071] In the present invention, the ratio of the mass of the transition metal in the transition metal sulfide dispersion to the volume of the dispersion solvent is preferably (4-12) g:10 L. As one embodiment of the present invention, the ratio of the mass of the twinned cadmium manganese sulfate in the twinned manganese sulfate cadmium dispersion to the volume of the dispersion solvent may be 4 g:10 L, 5 g:10 L, 6 g:10 L, 7 g:10 L, 8 g:10 L, 9 g:10 L, 10 g:10 L, 11 g:10 L, or 12 g:10 L.

[0072] In the present invention, the method for mixing the transition metal sulfide and the dispersion solvent is preferably ultrasound. The present invention has no particular limitation on the power and time of the ultrasound, as long as the transition metal sulfide and the dispersion solvent are uniformly dispersed.

[0073] In the present invention, the twinned manganese cadmium sulfur dispersion and the transition metal sulfide dispersion are preferably mixed by ultrasound. The present invention has no particular limitation on the power and duration of the ultrasound, as long as the twinned manganese cadmium sulfur dispersion and the transition metal sulfide dispersion are uniformly dispersed.

[0074] In the present invention, the interfacial self-assembly is preferably performed by stirring at a temperature suitable for interfacial self-assembly, and drying the resulting mixture of the twinned manganese cadmium sulfate dispersion and the transition metal sulfide dispersion. During the stirring at the self-assembly temperature until the solvent evaporates and dries, a heterojunction is formed by the interaction between the twinned manganese cadmium sulfate and the transition metal sulfide.

[0075] In the present invention, the temperature of the interfacial self-assembly is preferably 60-70°C, more preferably 60-68°C; the time of the interfacial self-assembly is preferably 1-3 hours, more preferably 1.5-2 hours. In the present invention, the interfacial self-assembly is preferably carried out under stirring, and the stirring speed is preferably 400-500 rpm, more preferably 440-460 rpm.

[0076] The present invention also provides the use of the sulfide heterojunction-based photocatalyst described in the above technical solution or the sulfide heterojunction-based photocatalyst prepared by the preparation method described in the above technical solution as a photocatalyst for degrading H2S to produce hydrogen.

[0077] The present invention does not particularly limit the method of using the sulfide heterojunction-based photocatalyst as a photocatalyst for degrading H2S to produce hydrogen, and any conventional method of photocatalyst for degrading H2S to produce hydrogen can be used.

[0078] In an embodiment of the present invention, the device for using the sulfide heterojunction-based photocatalyst in photocatalytic degradation of H2S to produce hydrogen is preferably as follows: Figure 1 As shown. Figure 1 As can be seen, the apparatus used in the present invention includes a gas generator, an absorption device, and an exhaust gas treatment device. The solution in the gas generator consists of HCl solution and Na2S solution; the absorption liquid in the absorption device is a 0.1 mol / L Na2S and 0.6 mol / L Na2SO3 solution; the solution in the exhaust device is NaOH solution, which is used to absorb residual H2S gas. An alarm is also provided to detect any H2S leaks.

[0079] In the present invention, the mechanism analysis diagram of the photocatalyst based on sulfide heterojunction as a photocatalyst for degrading H2S to produce hydrogen is preferably as follows: Figure 2 As shown. Figure 2 (a) It can be seen that T-MCS (twinned cadmium manganese sulfide) composed of WZ-MCS (hexagonal wurtzite cadmium manganese sulfide) and ZB-MCS (cubic sphalerite cadmium manganese sulfide) with different band structures will form an S-type homojunction structure in the bulk phase. Under light irradiation, the e on the valence band of the staggered WZ-MCS and ZB-MCS - They are all excited to transition to their respective conduction bands, leaving h + ; Under the action of S-type carrier transport mechanism, the e - It will move to the valence band of WZ-MCS, and the h + Combined, while the h of ZB-MCS + Then S 2- 、SO3 2- Directed oxidation to S2O3 2-This homojunction formed by the energy band difference of different crystal forms in the twin structure is distributed throughout the bulk of the semiconductor particles and has low interface resistance, effectively suppressing the bulk recombination of carriers. Due to the existence of the Schottky barrier, e - It can be irreversibly transferred to transition metal sulfides in a "one-way" manner, thereby rapidly converting H + Reduced to H2. Combined Figure 2 (b) Analysis shows that the CuS / T-MCS heterojunction is different from other homogeneous Schottky junctions in that the e - It will move to the valence band of ZB-MCS, and the h + Combination, while CuS h + Then S 2- 、SO3 2- Directed oxidation to S2O3 2- Therefore, the sulfide heterojunction-based photocatalyst provided by the present invention can be used as a photocatalyst for degrading H2S to produce hydrogen.

[0080] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0081] Example 1

[0082] A sulfide heterojunction-based photocatalyst, wherein the sulfide heterojunction-based photocatalyst is a heterojunction formed by twinned cadmium manganese sulfate and transition metal sulfide;

[0083] The sulfide heterojunction-based photocatalyst consists of 92 wt % of twinned cadmium manganese sulfide and 8 wt % of transition metal sulfide (NiS) by mass percentage;

[0084] The preparation method of the sulfide heterojunction-based photocatalyst is as follows:

[0085] (1) 1 mmol Mn(CH3COO)2·4H2O and 1 mmol Cd(CH3COO)2·4H2O were placed in 60 mL of water, dissolved, and then 8 mmol NaOH was added and stirred for 30 min. Subsequently, 4 mmol C2H5NS was added to obtain a pH of 13. When the solution turned yellow, it was transferred to a hydrothermal synthesis reactor, sealed, and heated to 180°C for 18 h. After the reaction was cooled to room temperature, it was centrifuged, washed, and dried to obtain twinned manganese cadmium sulfur, which was recorded as T-MCS.

[0086] (2) 1 mmol of Ni(CH3COO)2·4H2O and 50 mL of ethanol were mixed and stirred for 30 min and ultrasonically treated for 20 min. The resulting solution was mixed and stirred with 1 mmol of CH4N2S for 30 min, and subjected to hydrothermal reaction at 200°C for 12 h. The mixture was centrifuged and dried to obtain NiS nanoparticles.

[0087] (3) 92 mg of the T-MCS prepared in step (1) and 10 mL of ethanol were ultrasonically mixed for 2 h to obtain a T-MCS dispersion; 8 mg of the transition metal sulfide NiS particles prepared in step (2) were ultrasonically mixed with 10 mL of ethanol for 2 h to obtain a NiS dispersion; the T-MCS dispersion and the NiS dispersion were mixed, and the ethanol was evaporated by continuous stirring to obtain a green powdery sulfide heterojunction-based photocatalyst (denoted as 8 wt% NiS / T-MCS).

[0088] Example 2

[0089] A sulfide heterojunction-based photocatalyst, wherein the sulfide heterojunction-based photocatalyst is a heterojunction formed by twinned cadmium manganese sulfate and transition metal sulfide;

[0090] The sulfide heterojunction-based photocatalyst is composed of 92 wt % of twinned cadmium manganese sulfide and 8 wt % of transition metal sulfide (Ni3S4) by mass percentage;

[0091] The preparation method of the sulfide heterojunction-based photocatalyst is as follows:

[0092] (1) 1 mmol Mn(CH3COO)2·4H2O and 1 mmol Cd(CH3COO)2·4H2O were placed in 60 mL of water, dissolved, and then 8 mmol NaOH was added and stirred for 30 min. Subsequently, 4 mmol C2H5NS was added to obtain a pH of 13. When the solution turned yellow, it was transferred to a hydrothermal synthesis reactor, sealed, and heated to 180°C for 18 h. After the reaction was cooled to room temperature, it was centrifuged, washed, and dried to obtain twinned manganese cadmium sulfur, which was recorded as T-MCS.

[0093] (2) 2 mmol of Ni(CH3COO)2·4H2O, 6 mmol of NaOH, and 60 mL of water were mixed and stirred for 30 min. The resulting solution system was mixed and stirred with 3 mmol of C2H5NS for 30 min. The resulting solution system was subjected to a hydrothermal reaction at 140°C for 18 h and centrifuged to obtain Ni3S4 nanoparticles.

[0094] (3) 92 mg of T-MCS prepared in step (1) and 10 mL of ethanol were ultrasonically mixed for 2 h to obtain a T-MCS dispersion; 8 mg of transition metal sulfide Ni3S4 particles prepared in step (2) were ultrasonically mixed with 10 mL of ethanol for 2 h to obtain a Ni3S4 dispersion; the T-MCS dispersion and the Ni3S4 dispersion were mixed, and the ethanol was evaporated by continuous stirring to obtain a green powdery sulfide heterojunction-based photocatalyst (denoted as 8 wt% Ni3S4 / T-MCS).

[0095] Example 3

[0096] A sulfide heterojunction-based photocatalyst, wherein the sulfide heterojunction-based photocatalyst is a heterojunction formed by twinned cadmium manganese sulfate and transition metal sulfide;

[0097] The sulfide heterojunction-based photocatalyst consists of 92 wt % of twinned cadmium manganese sulfide and 8 wt % of transition metal sulfide (CuS) by mass percentage;

[0098] The preparation method of the sulfide heterojunction-based photocatalyst is as follows:

[0099] (1) 1 mmol Mn(CH3COO)2·4H2O and 1 mmol Cd(CH3COO)2·4H2O were placed in 60 mL of water, dissolved, and then 8 mmol NaOH was added and stirred for 30 min. Subsequently, 4 mmol C2H5NS was added to obtain a pH of 13. When the solution turned yellow, it was transferred to a hydrothermal synthesis reactor, sealed, and heated to 180°C for 18 h. After the reaction was cooled to room temperature, it was centrifuged, washed, and dried to obtain twinned manganese cadmium sulfur, which was recorded as T-MCS.

[0100] (2) 1 mmol of Cu(NO3)2·3H2O was dissolved in 40 mL of water, and 4 mmol of NaOH was added. After stirring for 30 min, 4 mmol of C2H5NS was added. The resulting solution was hydrothermally reacted at 180°C for 24 h and centrifuged to obtain CuS nanoparticles.

[0101] (3) 92 mg of the T-MCS prepared in step (1) and 10 mL of ethanol were ultrasonically mixed for 2 h to obtain a T-MCS dispersion; 8 mg of the transition metal sulfide CuS particles prepared in step (2) were ultrasonically mixed with 10 mL of ethanol for 2 h to obtain a CuS dispersion; the T-MCS dispersion and the CuS dispersion were mixed, and the ethanol was evaporated and removed by continuous stirring to obtain a green powdery sulfide heterojunction-based photocatalyst (denoted as 8 wt% CuS / T-MCS).

[0102] Example 4

[0103] A sulfide heterojunction-based photocatalyst, wherein the sulfide heterojunction-based photocatalyst is a heterojunction formed by twinned cadmium manganese sulfate and transition metal sulfide;

[0104] The sulfide heterojunction-based photocatalyst is composed of 96 wt % of twinned cadmium manganese sulfide and 4 wt % of transition metal sulfide (NiS2) by mass percentage;

[0105] The preparation method of the sulfide heterojunction-based photocatalyst is as follows:

[0106] (1) 1 mmol Mn(CH3COO)2·4H2O and 1 mmol Cd(CH3COO)2·4H2O were placed in 60 mL of water, dissolved, and then 8 mmol NaOH was added and stirred for 30 min. Subsequently, 4 mmol C2H5NS was added to obtain a pH of 13. When the solution turned yellow, it was transferred to a hydrothermal synthesis reactor, sealed, and heated to 180°C for 18 h. After the reaction was cooled to room temperature, it was centrifuged, washed, and dried to obtain twinned manganese cadmium sulfur, which was recorded as T-MCS.

[0107] (2) 2 mmol of Ni(NO3)2·6H2O, 8 mmol of C2H5NS, and 50 mL of ethanol were mixed and stirred for 30 min. The resulting solution was subjected to a hydrothermal reaction at 180°C for 12 h and centrifuged to obtain NiS2 nanoparticles.

[0108] (3) 96 mg of T-MCS prepared in step (1) and 10 mL of ethanol were ultrasonically mixed for 2 h to obtain a T-MCS dispersion; 4 mg of transition metal sulfide NiS2 particles prepared in step (2) were ultrasonically mixed with 10 mL of ethanol for 2 h to obtain a NiS2 dispersion; the T-MCS dispersion and the NiS2 dispersion were mixed, and the ethanol was evaporated by continuous stirring to obtain a green powdery sulfide heterojunction-based photocatalyst (denoted as 4 wt% NiS2 / T-MCS).

[0109] Example 5

[0110] A sulfide heterojunction-based photocatalyst, wherein the sulfide heterojunction-based photocatalyst is a heterojunction formed by twinned cadmium manganese sulfate and transition metal sulfide;

[0111] The sulfide heterojunction-based photocatalyst is composed of 94 wt % of twinned cadmium manganese sulfide and 6 wt % of transition metal sulfide (NiS2) by mass percentage;

[0112] The preparation method of the sulfide heterojunction-based photocatalyst is as follows:

[0113] (1) 1 mmol Mn(CH3COO)2·4H2O and 1 mmol Cd(CH3COO)2·4H2O were placed in 60 mL of water, dissolved, and then 8 mmol NaOH was added and stirred for 30 min. Subsequently, 4 mmol C2H5NS was added to obtain a pH of 13. When the solution turned yellow, it was transferred to a hydrothermal synthesis reactor, sealed, and heated to 180°C for 18 h. After the reaction was cooled to room temperature, it was centrifuged, washed, and dried to obtain twinned manganese cadmium sulfur, which was recorded as T-MCS.

[0114] (2) 2 mmol of Ni(NO3)2·6H2O, 8 mmol of C2H5NS, and 50 mL of ethanol were mixed and stirred for 30 min. The resulting solution was subjected to a hydrothermal reaction at 180°C for 12 h and centrifuged to obtain NiS2 nanoparticles.

[0115] (3) 96 mg of T-MCS prepared in step (1) and 10 mL of ethanol were ultrasonically mixed for 2 h to obtain a T-MCS dispersion; 4 mg of transition metal sulfide NiS2 particles prepared in step (2) were ultrasonically mixed with 10 mL of ethanol for 2 h to obtain a NiS2 dispersion; the T-MCS dispersion and the NiS2 dispersion were mixed, and the ethanol was evaporated and removed by continuous stirring to obtain a green powdery sulfide heterojunction-based photocatalyst (denoted as 6 wt% NiS2 / T-MCS).

[0116] Example 6

[0117] A sulfide heterojunction-based photocatalyst, wherein the sulfide heterojunction-based photocatalyst is a heterojunction formed by twinned cadmium manganese sulfate and transition metal sulfide;

[0118] The sulfide heterojunction-based photocatalyst is composed of 92 wt % of twinned cadmium manganese sulfide and 8 wt % of transition metal sulfide (NiS2) by mass percentage;

[0119] The preparation method of the sulfide heterojunction-based photocatalyst is as follows:

[0120] (1) 1 mmol Mn(CH3COO)2·4H2O and 1 mmol Cd(CH3COO)2·4H2O were placed in 60 mL of water, dissolved, and then 8 mmol NaOH was added and stirred for 30 min. Subsequently, 4 mmol C2H5NS was added to obtain a pH of 13. When the solution turned yellow, it was transferred to a hydrothermal synthesis reactor, sealed, and heated to 180°C for 18 h. After the reaction was cooled to room temperature, it was centrifuged, washed, and dried to obtain twinned manganese cadmium sulfur, which was recorded as T-MCS.

[0121] (2) 2 mmol of Ni(NO3)2·6H2O, 8 mmol of C2H5NS, and 50 mL of ethanol were mixed and stirred for 30 min. The resulting solution was subjected to a hydrothermal reaction at 180°C for 12 h and centrifuged to obtain NiS2 nanoparticles.

[0122] (3) 92 mg of T-MCS prepared in step (1) and 10 mL of ethanol were ultrasonically mixed for 2 h to obtain a T-MCS dispersion; 8 mg of transition metal sulfide NiS2 particles prepared in step (2) were ultrasonically mixed with 10 mL of ethanol for 2 h to obtain a NiS2 dispersion; the T-MCS dispersion and the NiS2 dispersion were mixed, and the ethanol was evaporated by continuous stirring to obtain a green powdery sulfide heterojunction-based photocatalyst (denoted as 8 wt% NiS2 / T-MCS).

[0123] Example 7

[0124] A sulfide heterojunction-based photocatalyst, wherein the sulfide heterojunction-based photocatalyst is a heterojunction formed by twinned cadmium manganese sulfate and transition metal sulfide;

[0125] The sulfide heterojunction-based photocatalyst consists of 90 wt % of twinned cadmium manganese sulfide and 10 wt % of transition metal sulfide (NiS2) by mass percentage;

[0126] The preparation method of the sulfide heterojunction-based photocatalyst is as follows:

[0127] (1) 1 mmol Mn(CH3COO)2·4H2O and 1 mmol Cd(CH3COO)2·4H2O were placed in 60 mL of water, dissolved, and then 8 mmol NaOH was added and stirred for 30 min. Subsequently, 4 mmol C2H5NS was added to obtain a pH of 13. When the solution turned yellow, it was transferred to a hydrothermal synthesis reactor, sealed, and heated to 180°C for 18 h. After the reaction was cooled to room temperature, it was centrifuged, washed, and dried to obtain twinned manganese cadmium sulfur, which was recorded as T-MCS.

[0128] (2) 2 mmol of Ni(NO3)2·6H2O, 8 mmol of C2H5NS, and 50 mL of ethanol were mixed and stirred for 30 min. The resulting solution was subjected to a hydrothermal reaction at 180°C for 12 h and centrifuged to obtain NiS2 nanoparticles.

[0129] (3) Ultrasonic mixing of 90 mg of T-MCS prepared in step (1) and 10 mL of ethanol for 2 h to obtain a T-MCS dispersion; ultrasonic mixing of 10 mg of transition metal sulfide NiS2 particles prepared in step (2) and 10 mL of ethanol for 2 h to obtain a NiS2 dispersion; mixing the T-MCS dispersion and the NiS2 dispersion, continuously stirring and evaporating to remove ethanol, to obtain a green powdery sulfide heterojunction-based photocatalyst (denoted as 10 wt% NiS2 / T-MCS).

[0130] Example 8

[0131] A sulfide heterojunction-based photocatalyst, wherein the sulfide heterojunction-based photocatalyst is a heterojunction formed by twinned cadmium manganese sulfate and transition metal sulfide;

[0132] The sulfide heterojunction-based photocatalyst consists of 88 wt % of twinned cadmium manganese sulfide and 12 wt % of transition metal sulfide (NiS2) by mass percentage;

[0133] The preparation method of the sulfide heterojunction-based photocatalyst is as follows:

[0134] (1) 1 mmol Mn(CH3COO)2·4H2O and 1 mmol Cd(CH3COO)2·4H2O were placed in 60 mL of water, dissolved, and then 8 mmol NaOH was added and stirred for 30 min. Subsequently, 4 mmol C2H5NS was added to obtain a pH of 13. When the solution turned yellow, it was transferred to a hydrothermal synthesis reactor, sealed, and heated to 180°C for 18 h. After the reaction was cooled to room temperature, it was centrifuged, washed, and dried to obtain twinned manganese cadmium sulfur, which was recorded as T-MCS.

[0135] (2) 2 mmol of Ni(NO3)2·6H2O, 8 mmol of C2H5NS, and 50 mL of ethanol were mixed and stirred for 30 min. The resulting solution was subjected to a hydrothermal reaction at 180°C for 12 h and centrifuged to obtain NiS2 nanoparticles.

[0136] (3) 88 mg of T-MCS prepared in step (1) and 10 mL of ethanol were ultrasonically mixed for 2 h to obtain a T-MCS dispersion; 12 mg of transition metal sulfide NiS2 particles prepared in step (2) were ultrasonically mixed with 10 mL of ethanol for 2 h to obtain a NiS2 dispersion; the T-MCS dispersion and the NiS2 dispersion were mixed, and the ethanol was evaporated by continuous stirring to obtain a green powdery sulfide heterojunction-based photocatalyst (denoted as 12 wt% NiS2 / T-MCS).

[0137] Comparative Example 1

[0138] A NiS photocatalyst is prepared by mixing 1 mmol of Ni(CH3COO)2·4H2O and 50 mL of ethanol, stirring for 30 minutes, and ultrasonically treating for 20 minutes; mixing the obtained solution system with 1 mmol of CH4N2S, stirring for 30 minutes, performing a hydrothermal reaction at 200°C for 12 hours, and centrifugally drying to obtain NiS nanoparticles.

[0139] Comparative Example 2

[0140] A NiS2 photocatalyst is prepared by mixing 2 mmol of Ni(NO3)2·6H2O, 8 mmol of C2H5NS and 50 mL of ethanol and stirring for 30 minutes, subjecting the obtained solution system to a hydrothermal reaction at 180°C for 18 hours, and centrifugally drying to obtain NiS2 nanoparticles.

[0141] Comparative Example 3

[0142] A Ni3S4 photocatalyst is prepared by mixing 2 mmol of Ni(CH3COO)2·4H2O, 6 mmol of NaOH, and 60 mL of water and stirring for 30 minutes; mixing the obtained solution system with 3 mmol of C2H5NS and stirring for 30 minutes; subjecting the obtained solution system to a hydrothermal reaction at 140°C for 18 hours; and centrifuging and drying to obtain Ni3S4 nanoparticles.

[0143] Comparative Example 4

[0144] A CuS photocatalyst is prepared by dissolving 1 mmol of Cu(NO3)2·3H2O in 40 mL of water, adding 4 mmol of NaOH, stirring for 30 minutes, and then adding 4 mmol of C2H5NS. The resulting solution system is subjected to a hydrothermal reaction at 180°C for 24 hours, and centrifuged and dried to obtain CuS nanoparticles.

[0145] Comparative Example 5

[0146] The preparation method of hexagonal wurtzite cadmium manganese sulfate is as follows: first, 1mmol of Mn(CH3COO)2·4H2O and 1mmol of Cd(CH3COO)2·4H2O are placed in 60mL of water, stirred for 30min, and then 2mmol of L-cysteine ​​is added. Then, the mixture is transferred to a hydrothermal synthesis reactor, sealed, heated to 180℃ and reacted for 18h. After the reaction is cooled to room temperature, the mixture is centrifuged, washed and dried to obtain hexagonal wurtzite Mn 0.5 Cd 0.5 S, denoted as WZ-MCS.

[0147] Comparative Example 6

[0148] The preparation method of cubic sphalerite manganese cadmium sulfide is as follows: first, 10mmol of Mn(CH3COO)2·4H2O and 10mmol of Cd(CH3COO)2·4H2O are placed in 60mL of water, stirred for 30min, and then 4mmol of TAA is added. Then, the mixture is transferred to a hydrothermal synthesis reactor, sealed, heated to 180℃, and reacted for 18h. After the reaction is cooled to room temperature, the mixture is centrifuged, washed, and dried to obtain cubic sphalerite Mn. 0.5 Cd 0.5 S, denoted as ZB-MCS.

[0149] Test Example 1

[0150] (1) The T-MCS prepared in Example 1 was subjected to an X-ray diffraction test, and the obtained XRD pattern was as follows: Figure 3 As shown. Figure 3 It can be seen that the diffraction peak of T-MCS is slightly shifted compared with WZ-MCS or ZB-MCS. This is due to the fact that Mn 2+ The lattice shift caused by doping and the absence of impurity peaks in the spectrum indicate that the twinned sulfur-cadmium-manganese solid solution was successfully synthesized.

[0151] (2) The T-MCS prepared in Example 1 was tested by transmission electron microscopy, and the obtained TEM image was as follows: Figure 4 As shown. Figure 4 In the figure, (a) is the TEM image of twinned cadmium manganese sulfide, (b) is the HRTEM image of twinned cadmium manganese sulfide, and (c) is Figure 4 A partial enlarged view of Figure (b). Figure 4 Lattice fringes with a spacing of 0.366 nm can be clearly seen, corresponding to the (002) and (111) planes of WZ-MCS and ZB-MCS, which is consistent with the XRD results.

[0152] (3) X-ray diffraction tests were performed on the T-MCS prepared in Example 1, the NiS2 prepared in Example 6, and the 8wt% NiS2 / T-MCS, respectively, to obtain the XRD patterns shown in FIG. Figure 5 As shown. Figure 5 It can be seen that T-MCS is the main component of the twin structure, so comparing the PDF card of WZ-MCS, the characteristic peaks of T-MCS and NiS2 exist simultaneously in the composite sample, indicating that the composite catalyst was successfully prepared.

[0153] (4) The 8wt% NiS2 / T-MCS prepared in Example 6 was subjected to transmission electron microscopy testing, and the obtained TEM image was as follows: Figure 6 As shown. Figure 6 In the figure, (a) is a TEM image of 8wt% NiS2 / T-MCS prepared in Example 6, (b) is a HRTEM image of 8wt% NiS2 / T-MCS prepared in Example 6, and (c) is Figure 6A partial enlarged view of (b). Figure 6 It can be seen that the NiS2 nanoparticles in the 8wt% NiS2 / T-MCS prepared in Example 6 were successfully loaded onto the surface of T-MCS, with lattice fringes with a spacing of 0.366 nm corresponding to the (002) and (111) planes of WZ-MCS and ZB-MCS, and the lattice fringes of 0.283 nm came from the (200) plane of NiS2, which is also consistent with the XRD results.

[0154] (5) The sulfide heterojunction-based photocatalysts prepared in Examples 1 to 3 and Example 6, the CuS prepared in Comparative Example 4, the T-MCS prepared in Example 1, the WZ-MCS prepared in Comparative Example 5, and the ZB-MCS prepared in Comparative Example 6 were tested for photocatalytic hydrogen production. The test method was as follows: the test was carried out in a Labsolar-IIIAG type photocatalytic decomposition H2S hydrogen production device, the light source was a 300W xenon lamp (CEL-HXF300), and the illumination area was 19.63 cm 2 Before hydrogen production, the light intensity was measured by a light radiometer (PL-MW2000); the specific operation was as follows: first, a sacrificial agent mixture was prepared, i.e. Figure 1 50mL of H2S absorption liquid was prepared by the device; then 10mg of the sample to be tested was dispersed in a sacrificial agent (0.1mol / L Na2S and 0.6mol / LNa2SO3 solution that absorbed 0.3mol H2S), and the suspension was placed in a reactor for magnetic stirring; after the device was set up, the air inside the device and the sacrificial agent mixture was vacuumed to remove; finally, the hydrogen production experiment was started under illumination, and the hydrogen production rate was measured every 0.5h; the resulting hydrogen production rate graph is shown in Figure 2. Figure 7 shown.

[0155] Depend on Figure 7 It can be seen that T-MCS has a twin homojunction structure and excellent hydrogen production effect, which are ZB-MCS (954.39 μmol·g -1 ·h -1 ) and WZ-MCS (18.92 mmol·g -1 ·h -1 ) by 26 times and 1.3 times, respectively, for the catalyst compositions for photocatalytic decomposition of H2S to produce hydrogen based on sulfide homogeneous heterojunction photocatalysts prepared in Examples 1 to 6, all are improved relative to CuS.

[0156] Since the NiS2 effect is more significant than that of other transition metal sulfides in hydrogen production, the present invention sets Examples 4 to 8 to study the effect of NiS2 loading on hydrogen production. Figure 8 It can be seen that the hydrogen production rate of (8wt% NiS2 / T-MCS) provided by Example 6 is the highest, which is 45.06mmol·g -1 ·h-1 , T-MCS nanoparticles provided in Example 1 (24.99 mmol·g -1 ·h -1 ) increased by 1.8 times.

[0157] The NiS2 / T-MCS system with the best hydrogen production effect was S 2- / SO3 2- Translational research, by Figure 9 Visible. Figure 9 In the figure, (a) is the infrared spectra of 0.1MNa2S / 0.6M Na2SO3 solution before and after absorbing H2S; (b) is the infrared spectra of different photocatalysts after reacting in 0.1M Na2S / 0.6M Na2SO3 solution that has absorbed H2S. Figure 9 It can be seen that after absorbing H2S, some S2O3 2- After 5 hours of reaction, pure T-MCS and NiS2 can remove SO3 2- Converted to S2O3 2- 8wt% NiS2 / T-MCS achieved better conversion than both monomers, corresponding to its optimal hydrogen production in the system. Titration of 8wt% NiS2 / T-MCS solutions after 5 and 12 hours of reaction with 0.1 mol / L iodine standard solution yielded the following results (Table 1).

[0158] Table 1 NiS2 / T-MCS system conversion titration results

[0159] Sample and reaction time <![CDATA[V 待测 / mL]]> <![CDATA[V 终点 / mL]]> <![CDATA[XS2O3 2- / mg·L -1 ]]> <![CDATA[8wt%NiS2 / T-MCS(5h)]]> 17.8 67.32 42407.82 <![CDATA[8wt%NiS2 / T-MCS(12h)]]> 15.0 58.22 43521.39

[0160] As can be seen from Table 1, the titration results of 8 wt % NiS2 / T-MCS solution after reaction for 5 h and 12 h with 0.1 mol / L iodine standard solution were 42407.82 mg / L and 43521.39 mg / L respectively.

[0161] The above results demonstrate that the sulfide heterojunction-based photocatalyst provided by the present invention exhibits excellent catalytic activity when used as a photocatalyst for the degradation of H2S to produce hydrogen. This is because the sulfide heterojunction-based photocatalyst provided by the present invention is a heterojunction formed by twinned cadmium manganese sulfide and transition metal sulfide, resulting in excellent structural stability; its twinned homojunction can provide more photogenerated electrons. Therefore, when the catalyst provided by the present invention is used for the photocatalytic degradation of H2S to produce hydrogen, the photocatalyst's Schottky junction can reduce the hydrogen production overpotential, effectively decomposing H2S to produce hydrogen, and simultaneously producing the high-value-added product Na2S2O3.

[0162] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A sulfide heterojunction-based photocatalyst, wherein the sulfide heterojunction-based photocatalyst is a heterojunction formed by twinned cadmium manganese sulfate and a transition metal sulfide; Calculated by mass percentage, the sulfide heterojunction-based photocatalyst comprises 88-96 wt % of twinned cadmium manganese sulfide and 4-12 wt % of transition metal sulfide.

2. The sulfide heterojunction-based photocatalyst according to claim 1, characterized in that: The transition metal sulfide includes one or more of NiS, NiS2, Ni3S4 and CuS.

3. The method for preparing the sulfide heterojunction-based photocatalyst according to claim 1 or 2, comprising the following steps: (1) mixing a soluble manganese source, a soluble cadmium source, a soluble sulfur source, an alkaline regulator, and water to obtain an alkaline raw material solution, and subjecting the alkaline raw material solution to a hydrothermal reaction to obtain twinned sulfur-cadmium manganese; The molar ratio of the manganese element in the soluble manganese source, the cadmium element in the soluble cadmium source, and the sulfur element in the soluble sulfur source is (0.25-2): (0.25-2): (4-6); (2) mixing a soluble transition metal salt, a soluble sulfur source, and a solvent, and performing a solvothermal reaction to obtain a transition metal sulfide; (3) The twinned manganese cadmium sulfide obtained in step (1), the transition metal sulfide obtained in step (2) and a dispersing solvent are mixed and subjected to interfacial self-assembly to obtain a photocatalyst based on a sulfide homogeneous heterojunction; the mass ratio of the twinned manganese cadmium sulfide to the transition metal sulfide is (88-96): (4-12).

4. The preparation method according to claim 3, characterized in that The soluble manganese source in step (1) includes one or more of manganese chloride, manganese nitrate and manganese acetate; the soluble cadmium source includes one or more of cadmium chloride, cadmium nitrate and cadmium acetate; and the soluble sulfur source is C2H5NS or CH4N2S.

5. The preparation method according to claim 3, characterized in that The pH value of the alkaline raw material solution in step (1) is 13-14.

6. The preparation method according to claim 3, characterized in that The temperature of the hydrothermal reaction in step (1) is 180-200° C.; the time of the hydrothermal reaction is 6-24 hours.

7. The preparation method according to claim 3, characterized in that The soluble transition metal salt in step (2) includes a soluble nickel salt or a soluble copper salt; the soluble sulfur source includes C2H5NS or CH4N2S.

8. The preparation method according to claim 3, characterized in that The temperature of the solvent thermal reaction in step (2) is 140 to 200° C.; and the time of the solvent thermal reaction is 12 to 24 hours.

9. The preparation method according to claim 3, characterized in that The temperature of the interface self-assembly in step (3) is 60-70° C.; and the time of the interface self-assembly is 1-3 hours.

10. Use of the sulfide heterojunction-based photocatalyst according to any one of claims 1 to 2 or the sulfide heterojunction-based photocatalyst prepared by the preparation method according to any one of claims 3 to 9 as a photocatalyst for degrading H2S to produce hydrogen.

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