A preparation method for a sulfur-rich bimetallic co-catalyst formed by in-situ light-induced deposition and its photocatalytic hydrogen production

Abstract

The present invention discloses a method for preparing a sulfur-rich bimetallic co-catalyst formed by in-situ light-induced deposition and photocatalytic hydrogen production thereof, wherein the bimetallic co-catalyst is formed by in-situ light-induced deposition and photocatalytic hydrogen production thereof. 2+x W heteroatom was introduced to form MoWS 2+x Bimetallic co-catalysts increase the active sites of coordinated unsaturated S and optimize the S-H ads The bond energy is increased, promoting the desorption of atomic H, thereby improving the hydrogen evolution activity of sulfur vacancy-modified CdS under visible light. The bimetallic cocatalyst prepared by this method has the characteristics of rich active sites, rapid charge transfer, and extended carrier lifetime. The preparation method of the entire material has the advantages of short time consumption, low energy consumption, simple operation, and easy repeatability. It maximizes the catalytic activity of the cocatalyst and establishes a carrier interface transmission channel, providing a strong theoretical basis and practical approach for the rational construction of high-efficiency functional photocatalysts. 2+x / CdS v The SEM image shows the crystal rod morphology, MoWS 2+x / CdS v The highest hydrogen production rate of the crystal rod under 300W Xe (λ≥420nm) lamp reached 9166.13μmol·h ‑1 ·g ‑1 .

Description

Technical Field

[0001] The invention relates to an in-situ light-induced deposition method, a preparation method for forming a sulfur-rich bimetallic co-catalyst, and belongs to the technical field of preparation of metal catalytic materials. Background Art

[0002] In order to reduce the excessive use of fossil fuels and alleviate the energy crisis and environmental pollution problems, it is urgent to vigorously develop clean energy and promote the construction of a low-carbon, safe and clean modern energy system. Hydrogen energy has the characteristics of high density, high conversion efficiency, no pollution and high calorific value, and is considered to be one of the most promising energy sources. The green hydrogen production technology that uses semiconductor photocatalysts to convert solar energy into hydrogen energy has attracted widespread attention in solving the energy crisis. However, for most single-component photocatalysts (such as CdS), they usually exhibit low photocatalytic activity due to factors such as poor photostability, low separation efficiency of photogenerated carriers, and slow interfacial catalytic reactions. Co-catalysts are often introduced to solve this problem, mainly because co-catalysts can increase hydrogen evolution active sites, enhance visible light absorption, promote charge separation, and increase catalyst photostability. Among them, low-cost transition metal sulfides (especially MoS2) have been proven to be effective photocatalytic hydrogen evolution co-catalysts due to the presence of active S catalytic sites on their surfaces. However, the co-catalytic activity of MoS2 is still affected by the number of active centers and the SH ads Theoretical and experimental results show that the unsaturated S edge of MoS2 surface can capture and enrich H + active center, thereby optimizing SH ads Therefore, by improving the preparation method to create a sulfur-rich environment, introducing heteroatoms to construct a bimetallic co-catalyst system, and regulating the surface electron distribution, the active sites are increased and SH ads Bond energy optimization is a simple, efficient and feasible strategy.

[0003] In-situ photoinduced deposition (IPD) is a novel nanomaterial preparation technology. It utilizes the principle of photochemical reactions. Illumination in a liquid phase reduces metal ions into metal nanoparticles, thereby introducing heteroatoms into the catalyst and altering the electron distribution in the system. Materials obtained using this method exhibit excellent dispersibility and stability. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems of serious photocorrosion of CdS catalyst and insufficient active sites, and to provide a new catalyst preparation technology with simple preparation process, convenient operation and low cost. 2+x / CdS vIt has good dispersibility and stability, and exhibits excellent photocatalytic hydrogen production activity. This preparation method can be applied to more photocatalytic systems to overcome the shortcomings of current co-catalyst modification technology, such as complexity and high cost.

[0005] In order to solve the above technical problems, the technical solution proposed by the present invention is: a simple method for preparing a sulfur-rich bimetallic co-catalyst by in-situ light-induced deposition, comprising the following steps:

[0006] a. First, cadmium acetate dihydrate and ethylenediamine were stirred at room temperature, and then thioacetamide and sodium borohydride were added thereto, and the mixture was stirred at room temperature to obtain a white viscous liquid;

[0007] b. Pour the solution in step a into a reactor to obtain an orange-yellow precipitate;

[0008] c. Centrifuge the precipitate obtained in step b, wash it, and dry it in an oven to obtain an orange-yellow CdS solid powder with sulfur vacancies. v ;

[0009] d. CdS obtained in step c v Dissolve in ethanol solution, then add the prepared WCl5 and (NH4)2MoS4 solution in a certain proportion, and then complete the photoreduction reaction of the mixed solution under LED light to obtain MoWS 2+x / CdS v The solution is washed and dried to obtain MoWS. 2+x / CdS v (x>0) solid powder.

[0010] Preferably, in step a, the molar ratio of cadmium acetate dihydrate: sodium borohydride: thioacetamide is 1:2:4.

[0011] Preferably, the temperature and time used in the reaction kettle in step b are: 180° C. and 24 h, respectively.

[0012] Preferably, the oven drying temperature and time in step c are: 60°C, 12 hours or more, the centrifugal speed and time are: 8000 rpm, 5 minutes, and CdS with sulfur vacancies is abbreviated as CdS v .

[0013] Preferably, the mass percentage of W and Mo in step d is controlled to be CdS vThe ratio of WCl₅ and (NH₄)₂MoS₄ solutions, primarily the mass ratios of Mo and W atoms, were Mo:W = 2:1, 1.3:1.7, and 1:2, respectively. These samples were abbreviated as MWC-1, MWC-2, and MWC-3, and were tested for photocatalytic hydrogen production. The LED lamp was a UV lamp (λ ≥ 390 nm).

[0014] In order to solve the above technical problems, another technical solution proposed by the present invention is: the sulfur-rich bimetallic co-catalyst prepared by the in-situ light-induced deposition method is used for photocatalytic hydrogen production, comprising the following steps:

[0015] a. Take 1 mg of different photodeposits MWC-1, MWC-2, and MWC-3 in a round-bottom flask, add sacrificial agent and water, ventilate for 20 minutes, and then place under the same light source for photocatalytic hydrogen production;

[0016] b. The chromatographic reading of hydrogen can be obtained by gas chromatograph, and then the hydrogen production can be calculated by the corresponding formula;

[0017] Preferably, in step a, the sacrificial agents are Na2SO3 and Na2S, which are 0.8875 g and 1.2 g respectively, and the gas introduced is nitrogen. After irradiation under a 300W Xe (λ≥420nm) lamp for 2 hours, hydrogen is removed in three times.

[0018] Preferably, after the reaction is completed, the hydrogen taken out three times is injected into a gas chromatograph to measure the chromatographic reading of hydrogen production, and the average value is taken and the specific amount of hydrogen is obtained by calculation.

[0019] Preferably, the method comprises the following steps:

[0020] (1) Preparation of CdS v Crystal rod: 1.3325g Cd(COOCH3)·2H2O was added to a beaker containing 30mL ethylenediamine and stirred for 20min. Then, 1.5g thioacetamide and 0.3783g NaBH4 were added and stirred for 1h to obtain a white uniform suspension. The solution was added to a 50mL reactor and kept at 180℃ for 24h. The orange-yellow product was collected and washed three times with deionized water and ethanol respectively. The centrifuge speed was 8000r / min for 5min. Finally, it was dried in a 60℃ oven to obtain CdS v crystal rods;

[0021] (2) Preparation of MWC-3 crystal rods: 50 mg CdS v Disperse in 80 mL of ethanol; then add 27.7 μL of WCl5 / ethanol (0.1 mol·L -1) and 19.2 μL of (NH4)2MoS4 / DMF (0.1 mol·L -1 ), the mass percentage of W and Mo is controlled to be CdS v The mass ratio of Mo and W atoms is 3wt%, Mo:W=1:2; secondly, the above solution was purged with N2 for 15min, and then irradiated with LED (λ≥390nm) light for 2h to convert sulfur-rich MoWS 2+x Deposition onto CdS v Finally, the resulting suspension was centrifuged, washed three times with ethanol, and dried in a vacuum oven at 60°C overnight to collect the product;

[0022] (3) Photocatalytic hydrogen production application, the steps are as follows:

[0023] Take 1 mg of photodeposited MWC-3 in a round-bottom flask, add 0.8875 g of Na2SO3 and 1.2 g of Na2S sacrificial agent and 20 mL of deionized water, ventilate for 20 minutes, and then place it under a 300W Xe lamp for 2 hours, and then perform photocatalytic hydrogen production. After the reaction is completed, hydrogen is taken out three times and injected into the gas chromatograph to obtain hydrogen-related data, take the average value and calculate the specific hydrogen amount.

[0024] Beneficial effects

[0025] The present invention combines sulfur-rich MoWS with different Mo and W atomic mass ratios. 2+x Catalyst photodeposition on CdS v On the surface, different photodeposited MoS 2+x / CdS v , MWC-1, MWC-2, MWC-3, MWC-4, and then applied them to the field of photocatalysis to test the performance of HER photocatalytic hydrogen evolution. Compared with other methods, the light-induced deposition method has the advantages of simple operation, low energy consumption, low equipment cost, and harmlessness to the environment. In the prior art, Gao et al. used MoWS 2+x The co-catalyst is loaded on the TiO2 surface, and the photocatalytic hydrogen production rate under LED light (λ = 365nm) is 4620.8μmol·h -1 ·g -1 about.

[0026] The SEM of pure CdS shows the morphology of nanorods. Its photocatalytic hydrogen production rate under visible light is 1222.8 μmol·h -1 ·g -1 But pure CdS v The SEM image shows the crystal rod morphology, pure CdS v The photocatalytic hydrogen production rate under visible light is 3578.97 μmol·h -1 ·g -1, indicating that the introduction of vacancies in CdS can greatly improve the hydrogen production rate. 2+x / CdS v The diffraction pattern of the crystal rod is similar to that of pure CdS and pure CdS v Similar diffraction peaks, MoWS 2+x / CdS v The SEM image shows the crystal rod morphology, MoWS 2+x / CdS v The hydrogen production rate of the crystal rod was as high as 9166.13 μmol·h when irradiated under a 300W Xe (λ≥420nm) lamp for 2 hours under visible light. -1 ·g -1 .

[0027] In Example 4 of the present invention, MWC-3 is used as a co-catalyst for photocatalytic hydrogen production, which is the most preferred. The UV-visible diffuse reflectance spectrum (such as Figure 8 ) It can be observed that CdS v , MoS 2+x / CdS v The absorption peaks of MWC-3 and MWC-3 are about 500nm. At the same time, the light absorption intensity of MWC-3 is significantly enhanced in the visible light range, which proves that MWC-3 has an excellent light response range, which will help to improve the photocatalytic hydrogen production activity. Figure 9 ), MWC-3, MoS 2+x / CdS v and CdS v There are two similar Raman peaks, and there are two Raman peaks of Mo-S and WS in MWC-3, indicating the successful preparation of MWC-3 crystal rods. Figure 10 ), the photocatalytic hydrogen production activity is the highest, and its hydrogen production rate under visible light reaches 9166.13 μmol·h -1 ·g -1 At the same time, the photocatalytic hydrogen production rate diagram of MWC-3 crystal rod under different wavelengths of LED light (such as Figure 11 ) and apparent quantum yield diagrams (such as Figure 12 ), the photocatalytic hydrogen production rate at 390 nm is 19637 μmol·h -1 ·g -1, , the apparent quantum yield is the highest, which is 19.13%. And the long cycle steady state diagram under visible light (such as Figure 13 ), the cyclic stability can be maintained within 24 hours. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described below with reference to the accompanying drawings.

[0029] Figure 1 The CdS and CdS prepared in Examples 1 to 5 of the present invention are v 、MoS 2+x / CdS v and X-ray diffraction patterns of MWC-x;

[0030] Figure 2 is a scanning electron microscope image of CdS nanorods;

[0031] Figure 3 CdS v Scanning electron microscope image of a crystal rod;

[0032] Figure 4 MoS 2+x / CdS v Scanning electron microscope image of a crystal rod;

[0033] Figure 5 is a scanning electron microscope image of MWC-3 crystal rod;

[0034] Figure 6 Transmission electron microscopy image of MWC-3 crystal rod;

[0035] Figure 7 This is a high-resolution transmission electron micrograph of a MWC-3 crystal rod;

[0036] Figure 8 The CdS prepared in Examples 1 to 5 of the present invention v 、MoS 2+x / CdS v and UV-visible diffuse reflectance spectra of MWC-3;

[0037] Figure 9 The CdS prepared in Examples 1 to 5 of the present invention v 、MoS 2+x / CdS v and Raman spectra of MWC-3;

[0038] Figure 10 The CdS and CdS prepared in Examples 1 to 5 of the present invention are v 、MoS 2+x / CdS v and hydrogen production rate diagram of MWC-x;

[0039] Figure 11 This is a graph showing the hydrogen production rate of MWC-3 prepared in Example 4 of the present invention under LED lights of different wavelengths;

[0040] Figure 12 This is a graph showing the apparent quantum yield of MWC-3 prepared in Example 4 of the present invention under LED lights of different wavelengths;

[0041] Figure 13 This is a long-cycle steady-state diagram of MWC-3 prepared in Example 4 of the present invention under a 300W Xe (λ≥420nm) lamp. DETAILED DESCRIPTION

[0042] The above and other technical features and advantages of the present invention are described in more detail below with reference to the accompanying drawings.

[0043] Example 1

[0044] 1. Preparation of CdS nanorods: Add 1.3325 g of Cd(COOCH₃)·2H₂O to a beaker containing 30 mL of ethylenediamine and stir for 20 minutes. Then, add 1.5 g of thioacetamide and continue stirring for 1 hour to obtain a white, uniform suspension. This solution is then added to a 50 mL reactor and maintained at 180°C for 24 hours. The orange-yellow product is collected and washed three times with deionized water and ethanol, respectively, by centrifugation at 8000 rpm for 5 minutes each. Finally, dry in a 60°C oven to obtain the CdS nanorods.

[0045] 2. Preparation of CdS v Crystal rod: 1.3325g Cd(COOCH3)·2H2O was added to a beaker containing 30mL of ethylenediamine and stirred for 20min. 1.5g of thioacetamide and 0.3783g of NaBH4 were then added and stirred for 1h to obtain a white uniform suspension. The solution was added to a 50mL reactor and kept at 180°C for 24h. The orange-yellow product was collected and washed three times with deionized water and ethanol respectively, centrifuged at 8000r / min for 5min, and finally dried in a 60°C oven to obtain CdS v Crystal rod.

[0046] 3. Preparation of MoS 2+x / CdS v Crystal rod: 50mg CdS v Disperse in 80 mL of ethanol. Then add 57.7 μL of (NH4)2MoS4 / DMF (0.1 mol·L -1 )(The mass percentage of Mo is controlled to be CdS v Next, the solution was purged with N2 for 15 min and then irradiated with LED (λ≥390 nm) light for 2 h. Finally, the resulting suspension was centrifuged, washed three times with ethanol, and dried in a vacuum oven at 60°C overnight to collect the product.

[0047] 4. Application of photocatalytic hydrogen production, the steps are as follows:

[0048] Take 1 mg of photoprecipitated CdS and CdS respectivelyv and MoS 2+x / CdS v In a round-bottom flask, add 0.8875g Na2SO3, 1.2g Na2S sacrificial agent and 20mL deionized water, mix well and ventilate for 20 minutes, then place it under a 300W Xe (λ≥420nm) lamp for 2 hours, and then perform photocatalytic hydrogen production. After the reaction is completed, hydrogen is taken out three times and injected into the gas chromatograph to obtain hydrogen-related data, take the average value and calculate the specific hydrogen amount.

[0049] 5. Pure CdS v It shows diffraction peaks similar to those of pure CdS (such as Figure 1 ). SEM image of pure CdS (such as Figure 2 ) is the nanorod morphology, the hydrogen production rate diagram of pure CdS (such as Figure 10 ), and its hydrogen production rate is 1222.8 μmol·h -1 ·g -1 But pure CdS v SEM images (such as Figure 3 ) is a crystal rod morphology. Pure CdS v The hydrogen production rate diagram (such as Figure 10 ), and its hydrogen production rate is 3578.97 μmol·h -1 ·g -1 This shows that the introduction of vacancies in CdS can greatly improve the hydrogen production rate. 2+x / CdS v The diffraction pattern of the crystal rod (such as Figure 1 ), which is comparable to pure CdS and pure CdS v Similar diffraction peaks, MoS 2+x / CdS v SEM images (such as Figure 4 ) is the crystal rod morphology, in the Raman spectrum (such as Figure 9 ), MoS 2+x / CdS v and CdS v There are two similar Raman peaks, and in MoS 2+x / CdS v There is a Mo-S Raman peak in the 2+x / CdS v Successful preparation of crystal rods. MoS 2+x / CdS v The hydrogen production rate diagram of the crystal rod (such as Figure 10 ), and its hydrogen production rate reached 4627.13 μmol·h -1 ·g -1 .

[0050] Example 2

[0051] 1. Preparation of CdS v Crystal rod: 1.3325g Cd(COOCH3)·2H2O was added to a beaker containing 30mL of ethylenediamine and stirred for 20min. 1.5g of thioacetamide and 0.3783g of NaBH4 were then added and stirred for 1h to obtain a white uniform suspension. The solution was added to a 50mL reactor and kept at 180°C for 24h. The orange-yellow product was collected and washed three times with deionized water and ethanol respectively, centrifuged at 8000r / min for 5min, and finally dried in a 60°C oven to obtain CdS v Crystal rod.

[0052] 2. Preparation of MWC-1 crystal rod: 50mg CdS v Disperse in 80 mL of ethanol. Then add 13.9 μL of WCl5 / ethanol (0.1 mol·L -1 ) and 38.5 μL of (NH4)2MoS4 / DMF (0.1 mol·L -1 )(The mass percentage of W and Mo is controlled to be CdS v 3wt%), the ratio of Mo and W atoms is: Mo:W=2:1; secondly, the above solution is purged with N2 for 15min, and then irradiated with LED (λ≥390nm) light for 2h to convert sulfur-rich MoWS 2+x Deposition onto CdS v Finally, the resulting suspension was centrifuged, washed three times with ethanol, and dried in a vacuum oven at 60 °C overnight to collect the product.

[0053] 3. Application of photocatalytic hydrogen production, the steps are as follows:

[0054] Take 1 mg of photodeposited MWC-1 in a round-bottom flask, add 0.8875 g of Na2SO3 and 1.2 g of Na2S sacrificial agent and 20 mL of deionized water, mix well and ventilate for 20 minutes, then place it under a 300W Xe (λ≥420nm) lamp for 2 hours, and then carry out photocatalytic hydrogen production. After the reaction is completed, hydrogen is taken out three times and injected into the gas chromatograph to obtain hydrogen-related data, take the average value and calculate the specific hydrogen amount.

[0055] 4. XRD diffraction pattern of MWC-1 crystal rod (such as Figure 1 ), which is comparable to pure CdS and pure CdS v Similar diffraction peaks, hydrogen production rate diagram of MWC-1 crystal rod (such as Figure 10 ), and its hydrogen production rate reached 5261.98 μmol·h -1 ·g -1 .

[0056] Example 3

[0057] 1. Preparation of CdS v Crystal rod: 1.3325g Cd(COOCH3)·2H2O was added to a beaker containing 30mL of ethylenediamine and stirred for 20min. 1.5g of thioacetamide and 0.3783g of NaBH4 were then added and stirred for 1h to obtain a white uniform suspension. The solution was added to a 50mL reactor and kept at 180°C for 24h. The orange-yellow product was collected and washed three times with deionized water and ethanol respectively, centrifuged at 8000r / min for 5min, and finally dried in a 60°C oven to obtain CdS v Crystal rod.

[0058] 2. Preparation of MWC-2 crystal rod: 50mg CdS v Disperse in 80 mL of ethanol. Then add 23.5 μL of WCl5 / ethanol (0.1 mol·L -1 ) and 25 μL of (NH4)2MoS4 / DMF (0.1 mol·L -1 )(The mass percentage of W and Mo is controlled to be CdS v 3wt%), the ratio of Mo and W atoms is: Mo:W=1.3:1.7; secondly, the above solution was purged with N2 for 15min, and then irradiated with LED (λ≥390nm) light for 2h to convert sulfur-rich MoWS 2+x Deposition onto CdS v Finally, the resulting suspension was centrifuged, washed three times with ethanol, and dried in a vacuum oven at 60 °C overnight to collect the product.

[0059] 3. Application of photocatalytic hydrogen production, the steps are as follows:

[0060] Take 1 mg of photodeposited MWC-2 in a round-bottom flask, add 0.8875 g of Na2SO3 and 1.2 g of Na2S sacrificial agent and 20 mL of deionized water, mix well and ventilate for 20 minutes, then place it under a 300W Xe (λ≥420nm) lamp for 2 hours, and then carry out photocatalytic hydrogen production. After the reaction is completed, hydrogen is taken out three times and injected into the gas chromatograph to obtain hydrogen-related data, take the average value and calculate the specific hydrogen amount.

[0061] 4. XRD diffraction pattern of MWC-2 crystal rod (such as Figure 1 ), which is comparable to pure CdS and pure CdS v Similar diffraction peaks, hydrogen production rate diagram of MWC-2 crystal rod (such as Figure 10 ), and its hydrogen production rate reached 7837.68 μmol·h -1 ·g-1 .

[0062] Example 4

[0063] 1. Preparation of CdS v Crystal rod: 1.3325g Cd(COOCH3)·2H2O was added to a beaker containing 30mL of ethylenediamine and stirred for 20min. 1.5g of thioacetamide and 0.3783g of NaBH4 were then added and stirred for 1h to obtain a white uniform suspension. The solution was added to a 50mL reactor and kept at 180°C for 24h. The orange-yellow product was collected and washed three times with deionized water and ethanol respectively, centrifuged at 8000r / min for 5min, and finally dried in a 60°C oven to obtain CdS v Crystal rod.

[0064] 2. Preparation of MWC-3 crystal rod: 50mg CdS v Disperse in 80 mL of ethanol. Then add 27.7 μL of WCl5 / ethanol (0.1 mol·L -1 ) and 19.2 μL of (NH4)2MoS4 / DMF (0.1 mol·L -1 )(The mass percentage of W and Mo is controlled to be CdS v 3wt%), the ratio of Mo and W atoms is: Mo:W=1:2; secondly, the above solution is purged with N2 for 15min, and then irradiated with LED (λ≥390nm) light for 2h to convert sulfur-rich MoWS 2+x Deposition onto CdS v Finally, the resulting suspension was centrifuged, washed three times with ethanol, and dried in a vacuum oven at 60 °C overnight to collect the product.

[0065] 3. Application of photocatalytic hydrogen production, the steps are as follows:

[0066] Take 1 mg of photodeposited MWC-3 in a round-bottom flask, add 0.8875 g of Na2SO3 and 1.2 g of Na2S sacrificial agent and 20 mL of deionized water, mix well and ventilate for 20 minutes, then place it under a 300W Xe (λ≥420nm) lamp for 2 hours, and then carry out photocatalytic hydrogen production. After the reaction is completed, hydrogen is taken out three times and injected into the gas chromatograph to obtain hydrogen-related data, take the average value and calculate the specific hydrogen amount.

[0067] 4. XRD diffraction pattern of MWC-3 crystal rod (such as Figure 1 ), which is comparable to pure CdS and pure CdS v Similar diffraction peaks. SEM image of MWC-3 ( Figure 5 ) behaves as pure CdS vSimilar crystal rod morphology, after photodeposition, the TEM image of MWC-3 (such as Figure 6 ) It can be seen that there are some particles MoWS on the surface 2+x Attached to CdS v Surface. Then through HRTEM image (such as Figure 7 ) It can be seen that MoWS 2+x It is amorphous and tightly attached to CdS v Surface. UV-visible diffuse reflectance spectrum (such as Figure 8 ) It can be observed that CdS v , MoS 2+x / CdS v The absorption peak of MWC-3 is about 500nm. Figure 9 ), MWC-3, MoS 2+x / CdS v and CdS v There are two similar Raman peaks, and there are two Raman peaks of Mo-S and WS in MWC-3, indicating that the successful preparation of MWC-3 crystal rods has strengthened the close contact of the interface and enriched the charge transfer channel. At the same time, the light absorption intensity of MWC-3 is significantly enhanced in the visible light range, proving that MWC-3 has good light absorption, which may help to improve the photocatalytic hydrogen production activity. The hydrogen production rate diagram of MWC-3 crystal rods under visible light (such as Figure 10 ), the photocatalytic hydrogen production activity was the highest, and its hydrogen production rate reached 9166.13 μmol·h -1 ·g -1 At the same time, the photocatalytic hydrogen production rate diagram of MWC-3 crystal rod under different wavelengths of LED light (such as Figure 11 ) and apparent quantum yield diagrams (such as Figure 12 ), the photocatalytic hydrogen production rate at 390 nm is 19637 μmol·h -1 ·g -1, , the apparent quantum yield is the highest, which is 19.13%. And the long cycle steady state diagram under visible light (such as Figure 13 ), the cyclic stability can be maintained within 24 hours.

[0068] Example 5

[0069] 1. Preparation of CdS vCrystal rod: 1.3325g Cd(COOCH3)·2H2O was added to a beaker containing 30mL of ethylenediamine and stirred for 20min. 1.5g of thioacetamide and 0.3783g of NaBH4 were then added and stirred for 1h to obtain a white uniform suspension. The solution was added to a 50mL reactor and kept at 180°C for 24h. The orange-yellow product was collected and washed three times with deionized water and ethanol respectively, centrifuged at 8000r / min for 5min, and finally dried in a 60°C oven to obtain CdS v Crystal rod.

[0070] 2. Preparation of MWC-4 crystal rod: 50mg CdS v Disperse in 80 mL of ethanol. Then add 37.4 μL of WCl5 / ethanol (0.1 mol·L -1 ) and 5.8 μL of (NH4)2MoS4 / DMF (0.1 mol·L -1 )(The mass percentage of W and Mo is controlled to be CdS v 3wt%), the ratio of Mo and W atoms is: Mo:W=0.3:2.7; secondly, the above solution was purged with N2 for 15min, and then irradiated with LED (λ≥390nm) light for 2h to convert sulfur-rich MoWS 2+x Deposition onto CdS v Finally, the resulting suspension was centrifuged, washed three times with ethanol, and dried in a vacuum oven at 60 °C overnight to collect the product.

[0071] 3. Application of photocatalytic hydrogen production, the steps are as follows:

[0072] Take 1 mg of photodeposited MWC-4 in a round-bottom flask, add 0.8875 g of Na2SO3 and 1.2 g of Na2S sacrificial agent and 20 mL of deionized water, mix well and ventilate for 20 minutes, then place it under a 300W Xe (λ≥420nm) lamp for 2 hours, and then carry out photocatalytic hydrogen production. After the reaction is completed, hydrogen is taken out three times and injected into the gas chromatograph to obtain hydrogen-related data, take the average value and calculate the specific hydrogen amount.

[0073] 4. XRD diffraction pattern of MWC-4 crystal rod (such as Figure 1 ), which is comparable to pure CdS and pure CdS v Similar diffraction peaks, hydrogen production rate diagram of MWC-4 crystal rod (such as Figure 10 ), and its hydrogen production rate reached 3940.06 μmol·h -1 ·g -1 .

[0074] This invention explores a method for synthesizing a sulfur-rich bimetallic cocatalyst using in-situ photoinduced deposition (PID) technology and its application in photocatalytic hydrogen production. This invention allows for simple, cost-effective, and efficient modification of a range of substrate semiconductor materials. The resulting photocatalytic material exhibits ultrahigh hydrogen production activity and long-term photostability in the visible light region.

[0075] The specific implementation methods described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above is only the most preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An application of a sulfur-rich bimetallic co-catalyst formed by in-situ light-induced deposition in photocatalytic hydrogen production, characterized by: The following steps are involved: (1) Preparation of CdS v Crystal rod: 1.3325 g Cd(COOCH3)·2H2O was added to a beaker containing 30 mL of ethylenediamine and stirred for 20 min. Then, 1.5 g of thioacetamide and 0.3783 g of NaBH4 were added and stirred for 1 h to obtain a white uniform suspension. The solution was added to a 50 mL reactor and kept at 180 °C for 24 h. The orange-yellow product was collected and washed three times with deionized water and ethanol respectively. The centrifuge speed was 8000 r / min for 5 min, and finally dried in a 60 °C oven to obtain CdS v crystal rods; (2) Preparation of MWC-3 crystal rods: 50 mg CdS v Disperse in 80 mL of ethanol; then add 27.7 μL of 0.1 mol·L -1 WCl5 / ethanol and 19.2 μL 0.1 mol·L -1 (NH4)2MoS4 / DMF, the mass percentage of W and Mo is controlled to be CdS v The mass ratio of Mo and W atoms is 3 wt%, Mo:W=1:2; secondly, the above solution was purged with N2 for 15 min, and then irradiated with LED λ≥390 nm light for 2 h to convert sulfur-rich MoWS 2+x Deposition onto CdS v Finally, the resulting suspension was centrifuged, washed three times with ethanol, and dried in a vacuum oven at 60 °C overnight to collect the product; (3) Application of photocatalytic hydrogen production, the steps are as follows: 1 mg of photodeposited MWC-3 was placed in a round-bottom flask, and 0.8875 g of Na2SO3, 1.2 g of Na2S sacrificial agent, and 20 mL of deionized water were added. The mixture was aerated for 20 min and then irradiated under a 300 W Xe λ≥420 nm lamp for 2 h to produce photocatalytic hydrogen. After the reaction was completed, hydrogen was taken out three times and injected into a gas chromatograph to obtain hydrogen-related data. The average value was taken and the specific hydrogen amount was calculated. The hydrogen production rate reached 9166.13 μmol·h -1 ·g - 1 The photocatalytic hydrogen production rate at 390 nm was 19637 μmol·h -1 ·g -1 , the apparent quantum yield is 19.13%, and the cycling stability can be maintained within 24 h under visible light.

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