A RuO x / Ru-indium zinc sulfide composite photocatalyst, preparation method and application thereof

Abstract

This invention discloses a RuO x This paper describes a Ru-indium zinc sulfide composite photocatalyst, its preparation method, and its applications, belonging to the field of photocatalysis. The preparation process involves dissolving polyvinylpyrrolidone, tributylphosphine, and a ruthenium source compound sequentially in a mixed solution of distilled water and methanol, followed by the addition of a ZnIn2S4 photocatalyst. The resulting mixed solution is reacted at 10℃–100℃ for at least 2 hours. After centrifugation, the solid is collected, washed, and dried to obtain RuO2. x / Ru-ZnIn2S4 composite photocatalyst. Ru and RuO x It can act as an active site for water oxidation, producing hydrogen peroxide. Meanwhile, Ru and RuO... x Both can effectively improve the separation efficiency of photogenerated carriers and enhance light absorption capacity, thereby significantly improving the performance of photocatalytic water splitting. RuO x The hydrogen production rate of the Ru-ZnIn2S4 composite photocatalyst is 532 μmol·g. ‑1 ·h ‑1 The hydrogen peroxide production rate reached 490 μmol·g ‑1 ·h ‑1 .

Description

Technical Field

[0001] This invention belongs to the field of photocatalysis, specifically relating to a RuO x / Ru-indium zinc sulfide composite photocatalyst, its preparation method and application. Background Technology

[0002] Photocatalytic water splitting to simultaneously produce hydrogen and hydrogen peroxide represents a one-step conversion of solar energy into clean energy (hydrogen) and high-value-added hydrogen peroxide, making it one of the most ideal ways to utilize solar energy. Compared to traditional photocatalytic water splitting to produce stoichiometric hydrogen and oxygen, this process significantly improves economic value. Therefore, developing efficient photocatalysts for simultaneous water splitting to produce hydrogen and hydrogen peroxide is of great significance. Indium zinc sulfide (ZnIn2S4) possesses advantages such as high light absorption coefficient, non-toxicity, and ease of preparation, making it a promising photocatalytic material. Previous studies have improved the photocatalytic hydrogen production performance of ZnIn2S4 through defect engineering, ion doping, and heterostructure construction, but these methods still fall far short of practical application requirements. More importantly, to date, ZnIn2S4 photocatalysts have struggled to achieve simultaneous water splitting to produce hydrogen and hydrogen peroxide, primarily due to low photogenerated carrier separation efficiency and a lack of effective oxidation active sites. Therefore, constructing RuO2... x The Ru-ZnIn2S4 composite photocatalyst is of great significance for achieving efficient photocatalytic water splitting and simultaneous production of hydrogen and hydrogen peroxide. Summary of the Invention

[0003] The purpose of this invention is to provide a RuO x / Ru-Indium Zinc Sulfide (hereinafter referred to as RuO) x / Ru-ZnIn2S4,1≦x≦4) composite photocatalyst, its preparation method and application.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A RuO x The preparation method of the Ru-ZnIn2S4 composite photocatalyst includes the following steps:

[0006] (1) Polyvinylpyrrolidone, tributylphosphine, and ruthenium source compound were dissolved in a mixture of distilled water and methanol in sequence, and then ZnIn2S4 photocatalyst was added.

[0007] (2) React the mixed solution obtained in step (1) at 10℃~100℃ for 2~24 hours;

[0008] (3) Centrifuge the product obtained in step (2), collect the solid, wash and dry it to obtain RuO. x / Ru-ZnIn2S4 composite photocatalyst.

[0009] Furthermore, in step (1), the molar ratio of ZnIn2S4 photocatalyst, ruthenium source compound, polyvinylpyrrolidone, and tributylphosphine is 1:(0.02~0.03):0.4:8.

[0010] Further, in step (1), the ruthenium source compound is selected from one or more of ruthenium chloride, ruthenium nitrate, ruthenium acetate, and ruthenium oxide in any proportion, and the concentration of the ruthenium source compound in the mixed solution of distilled water and methanol is 0.1 mmol / L to 5 mmol / L. Preferably, the ruthenium source compound is ruthenium chloride, and the concentration in the mixed solution of distilled water and methanol is 0.1 mmol / L to 1 mmol / L.

[0011] Furthermore, the drying in step (3) refers to drying at 10℃~100℃ for 2~24 hours.

[0012] Furthermore, the preparation process of the ZnIn2S4 photocatalyst is as follows:

[0013] S1. Dissolve the zinc source compound, indium source compound and sulfur source compound in a molar ratio of (1-2):(2-4):(4-8) in a mixed solution of distilled water and glycerol;

[0014] S2. React the mixed solution obtained in S1 at 10℃~100℃ for 2~24 hours;

[0015] S3. Centrifuge the product obtained in S2, collect the solid, wash and dry it to obtain the ZnIn2S4 photocatalyst.

[0016] Further, in step S1, the zinc source compound is selected from one or more of zinc chloride, zinc nitrate, zinc acetate, zinc carbonate, zinc sulfate, zinc hydroxide, and zinc oxalate in any proportion, and the concentration of the zinc source compound in the mixed solution of distilled water and glycerol is 0.001 mol / L to 10 mol / L. Preferably, the zinc source compound is selected from one or more of zinc chloride, zinc nitrate, zinc acetate, zinc carbonate, zinc sulfate, zinc hydroxide, and zinc oxalate in any proportion, preferably zinc chloride, and the concentration of zinc chloride in the mixed solution of distilled water and glycerol is 0.01 mol / L to 0.05 mol / L.

[0017] Further, in step S1, the indium source compound is selected from one or more of indium nitrate, indium chloride, indium sulfate, indium acetate, and indium oxide in any proportion, and the concentration of the indium source compound in the mixed solution of distilled water and glycerol is 0.001 mol / L to 10 mol / L. Preferably, the indium source compound is selected from one or more of indium nitrate, indium chloride, indium sulfate, indium acetate, and indium oxide in any proportion, preferably indium nitrate, and the concentration of indium nitrate in the mixed solution of distilled water and glycerol is 0.02 mol / L to 0.10 mol / L.

[0018] Further, in step S1, the sulfur source compound is selected from one or more of thioacetamide, sulfur powder, thiourea, and ammonium sulfide in any proportion, and the concentration of the sulfur source compound in the mixed solution of distilled water and glycerol is 0.001 mol / L to 10 mol / L. Preferably, the sulfur source compound is thioacetamide, and the concentration in the mixed solution of distilled water and glycerol is 0.04 mol / L to 0.20 mol / L.

[0019] Furthermore, the drying in step S3 refers to drying at 10℃~100℃ for 2~24 hours.

[0020] RuO prepared by the above method x / Ru-ZnIn2S4 composite photocatalyst.

[0021] The above RuO x Application of Ru-ZnIn2S4 composite photocatalyst in photocatalytic water splitting.

[0022] Beneficial effects of the present invention: Ru and RuO x It can act as an active site for water oxidation, producing hydrogen peroxide. Meanwhile, Ru and RuO... x Both can effectively improve the separation efficiency of photogenerated carriers and enhance light absorption capacity, thereby significantly improving the performance of photocatalytic water splitting. RuO x The hydrogen production rate of the Ru-ZnIn2S4 composite photocatalyst is 532 μmol·g. -1 ·h -1 The hydrogen peroxide production rate reached 490 μmol·g -1 ·h -1 Furthermore, the RuO of the present invention x The Ru-ZnIn2S4 composite photocatalyst has the advantages of simple preparation method and easy control of preparation conditions, and has certain research and application value. Attached Figure Description

[0023] Figure 1 These are X-ray diffraction patterns of the photocatalysts prepared in Examples 1, 2, 3, and 4 of this invention;

[0024] Figure 2 The following are the (a) ZnIn2S4, (b) Ru-ZnIn2S4, and (c) RuO prepared according to Examples 1, 2, 3, and 4 of this invention. x / Ru-ZnIn2S4 and (d) RuO x TEM image of / Ru-ZnIn2S4;

[0025] Figure 3 These are the ultraviolet-visible light absorption spectra of the photocatalysts prepared in Examples 1, 2, 3, and 4 of this invention;

[0026] Figure 4 These are the steady-state fluorescence spectra of the photocatalysts prepared in Examples 1, 2, 3, and 4 of this invention;

[0027] Figure 5 This is a graph showing the photocatalytic total water splitting rate of the photocatalysts prepared in Examples 1, 2, 3 and 4 of this invention. Detailed Implementation

[0028] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. The drawings illustrate preferred embodiments of the invention, but are not limited to the embodiments described herein.

[0029] Example 1

[0030] Preparation of ZnIn2S4 photocatalyst:

[0031] 96 mL of distilled water and 24 mL of glycerol were mixed evenly, and 545 mg (4.0 mmol) of zinc chloride, 1173 mg (4.0 mmol) of InCl3·4H2O and 601 mg (8.0 mmol) of thioacetamide were added sequentially. The mixture was stirred evenly and reacted in a water bath at 80 °C for 2 hours. After cooling and precipitation, the solid was centrifuged and washed with deionized water and anhydrous ethanol sequentially. The solid was dried at 60 °C for 10 h to obtain the ZnIn2S4 photocatalyst.

[0032] Example 2

[0033] Preparation of Ru-ZnIn2S4 photocatalyst:

[0034] 2000 mg (0.2 mmol) of polyvinylpyrrolidone (molecular weight 10000) was dissolved in a mixture of 50 mL of distilled water and 50 mL of methanol. 200 mg (0.5 mmol) of ZnIn2S4 was added, and the mixture was stirred at room temperature for 1 hour. Then, 1 mL (4.0 mmol) of tributylphosphine was added, and the mixture was stirred for 5 minutes. 0.14 mL of RuCl3 aqueous solution (17.74 mmol / L, 2.5 µmol) was added dropwise, and the mixture was stirred again for 1 hour. After centrifugation, the precipitate was washed with deionized water and anhydrous ethanol, and dried at 60 °C for 10 h to obtain the Ru-ZnIn2S4 composite photocatalyst.

[0035] Example 3

[0036] RuO x Preparation of Ru-ZnIn2S4 composite photocatalyst:

[0037] 0.2 mmol of polyvinylpyrrolidone was dissolved in a mixture of 50 mL distilled water and 50 mL methanol. 0.5 mmol of ZnIn₂S₄ was added, and the mixture was stirred at room temperature for 1 hour. Then, 4.0 mmol of tributylphosphine was added, and after stirring for 5 minutes, RuCl₃ aqueous solution (17.74 mmol / L, 10 µmol) was added dropwise. The mixture was stirred again for 1 hour, centrifuged, and the precipitate was washed with deionized water and anhydrous ethanol. The precipitate was then dried at 60 °C for 10 h to obtain the product RuO. x / Ru-ZnIn2S4 composite photocatalyst.

[0038] Example 4

[0039] RuO x Preparation of Ru-ZnIn2S4 composite photocatalyst:

[0040] 0.2 mmol of polyvinylpyrrolidone was dissolved in a mixture of 50 mL of distilled water and 50 mL of methanol. 0.5 mmol of ZnIn₂S₄ was added, and the mixture was stirred at 25°C for 1 hour. 4.0 mmol of tributylphosphine was added, and after stirring for 5 minutes, RuCl₃ aqueous solution (17.74 mmol / L, 15 µmol) was added dropwise. The mixture was stirred again for 1 hour. After centrifugation, the precipitate was washed with deionized water and anhydrous ethanol, and dried at 60°C for 10 hours to obtain the product RuO. x / Ru-ZnIn2S4 composite photocatalyst.

[0041] The photocatalysts obtained in Examples 1 to 4 were characterized in various ways. Figures 1 to 5 These are the characterization results of the photocatalyst's structure and performance. From Figure 1It can be seen that ZnIn2S4 was prepared in Example 1. Compared with ZnIn2S4, Ru-ZnIn2S4 and RuO x The characteristic peaks of / Ru-ZnIn2S4 are all shifted to the left, indicating that Ru is doped into the ZnIn2S4 lattice. From Figure 2 (a) It can be seen that the ZnIn2S4 prepared in Example 1 has a two-dimensional nanosheet structure. Figure 2 (b) It shows that the Ru-ZnIn2S4 prepared in Example 2 is still a two-dimensional nanosheet structure, and Ru doping does not affect the morphology of ZnIn2S4. Figure 2 (c) and (d) show that the samples prepared in Examples 3 and 4 have small RuO2 on their surfaces. x Nanoparticles, indicating that RuO has been prepared. x / Ru-ZnIn2S4 composite photocatalyst. Furthermore, the RuO on the surface of Example 4... x There are more nanoparticles. (From) Figure 3 It can be seen that the absorption band edge of ZnIn2S4 is around 520 nm. Ru doping and RuO... x Nanoparticle loading effectively enhanced light absorption in the 500-800 nm range, and with the increase of RuO x The enhancement is achieved by increasing the nanoparticle content. From... Figure 4 It can be seen that ZnIn2S4 exhibits a strong fluorescence peak, indicating severe recombination of photogenerated carriers. Ru doping and RuO... x Nanoparticle loading effectively reduced fluorescence intensity, demonstrating improved photogenerated carrier separation efficiency. Meanwhile, RuO x The increased nanoparticle content resulted in lower fluorescence intensity (Example 4), which further illustrates the influence of RuO2. x It can effectively separate photogenerated carriers.

[0042] The total water splitting experiment was conducted in a closed quartz reactor. A 300 W xenon lamp (λ>400 nm) was used as the light source, and 275 mL of distilled water was used as the reaction solution. The photocatalysts prepared in Examples 1 to 4 were added, with a dosage of 25 mg for each example. Before the experiment, the closed reactor was evacuated for approximately 30 minutes to remove air. After the reaction, 5 mL of the supernatant was collected by centrifugation, and 5 mL of 0.3 mM H₂SO₄ solution and 5 mL of 0.1 mM KMnO₄ solution were added. After mixing and reacting for 5–10 minutes, the light absorption of the solution was measured using a UV-Vis spectrophotometer (UV-2600, Shimadzu, Japan). The molar amount of H₂O₂ was calculated using a fitted formula. The chemical equation is as follows:

[0043]

[0044] The results of the total water splitting performance are as follows: Figure 5 As shown. From Figure 5 It can be seen that the hydrogen production and hydrogen peroxide production rates of pure ZnIn2S4 are relatively low, mainly due to the low separation efficiency of photogenerated carriers and the lack of effective oxidation active sites. Compared with pure ZnIn2S4, Ru-doped and RuO... x Nanoparticle loading significantly improves the photocatalytic performance of all-water splitting. Example 3 prepared RuO x The Ru-ZnIn2S4 composite photocatalyst exhibits the highest performance, achieving a hydrogen production rate of 532 μmol / g / h and a H2O2 production rate of 490 μmol / g / h, with a near 1:1 ratio between the two. This performance improvement stems from enhanced photogenerated carrier separation efficiency and the interaction between Ru and RuO. x Nanoparticles can all serve as oxidation active sites. If RuO is further increased... x Amount, RuO prepared in Example 4 x The reduced performance of the Ru-ZnIn2S4 composite photocatalyst may be due to RuO x This is caused by the light-blocking effect.

[0045] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A RuO x The preparation method of / Ru-ZnIn2S4 composite photocatalyst is characterized by, Obtained through the following steps: (1) Polyvinylpyrrolidone, tributylphosphine, and ruthenium source compound are dissolved sequentially in a mixed solution of distilled water and methanol, and then ZnIn2S4 photocatalyst is added; the molar ratio of ZnIn2S4 photocatalyst, ruthenium source compound, polyvinylpyrrolidone, and tributylphosphine is 1:(0.02~0.03):0.4:8; the ruthenium source compound is selected from one or more of ruthenium chloride, ruthenium nitrate, and ruthenium acetate in any proportion, and the concentration of the ruthenium source compound in the mixed solution of distilled water and methanol is 0.1 mmol / L to 5 mmol / L; (2) React the mixed solution obtained in step (1) at 10℃~100℃ for 2~24 hours; (3) Centrifuge the product obtained in step (2), collect the solid, wash and dry it to obtain RuO. x / Ru-ZnIn2S4 composite photocatalyst.

2. RuO prepared by the method of claim 1 x Application of / Ru-ZnIn2S4 composite photocatalyst in photocatalytic total water splitting to produce H2 and H2O2.

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