Application of indium sulfide supported bismuth monatomic composite material in production of hydrogen peroxide

Abstract

This invention relates to the application of an indium sulfide-supported bismuth single-atom composite material in hydrogen peroxide production. The indium sulfide-supported bismuth single-atom composite material of this invention comprises indium sulfide and bismuth single atoms supported on the indium sulfide, which are then dried to obtain a composite material (Bi-In₂S₃). The Bi-In₂S₃ composite material obtained by this invention has advantages such as high hydrogen peroxide yield and a simple and controllable preparation process. The Bi-In₂S₃ composite catalyst of this invention exhibits excellent hydrogen peroxide generation rate under actual catalytic reaction conditions; this is because indium sulfide has a narrow band gap and good visible light absorption performance; in addition, the single-atom bismuth adsorbs oxygen molecules in a Pauling-type configuration, avoiding the breaking of oxygen-oxygen bonds, and exhibiting good selectivity for the reduction of oxygen molecules with two electrons, significantly improving the efficiency of oxygen molecule activation into hydrogen peroxide.

Description

Technical Field

[0001] This invention relates to the technical field of indium sulfide catalyst materials, and in particular to the application of indium sulfide-supported bismuth single-atom composite materials in the production of hydrogen peroxide. Background Technology

[0002] With the development of green chemistry, higher demands are being placed on the sustainable preparation technologies of important chemical raw materials. Hydrogen peroxide (H2O2), as a clean oxidant with water as its only byproduct, is widely used in disinfection, bleaching, environmental remediation, and fine chemicals. However, traditional industrial production still mainly relies on the anthraquinone process, which is complex, energy-intensive, and produces a variety of unnecessary byproducts, failing to align with the industrial development direction of low-carbon and green development. Therefore, developing new environmentally friendly, low-energy-consumption, and scalable H2O2 preparation technologies is of great significance.

[0003] Photocatalysis, which utilizes solar energy to directly convert oxygen and water into H2O2, is considered an ideal alternative to the anthraquinone process. However, the efficiency of photocatalytic H2O2 generation is limited by two factors: first, the easy recombination of photogenerated electrons and holes leads to low quantum efficiency; second, the desired two-electron pathway (2e-hole) in the oxygen reduction reaction (ORR) is limited. - ORR requires a four-electron path (4e) with better thermodynamic driving force. - ORR competition makes it difficult to guarantee reaction selectivity. Therefore, constructing a system that can simultaneously improve carrier separation efficiency and promote 2e - ORR's photocatalytic system is key to the breakthrough in photocatalytic H2O2 technology.

[0004] In recent years, single-atom catalysts (SACs) have exhibited unique advantages in photocatalytic reactions due to their highly dispersed metal sites and uniform coordination environment. Single-atom sites can serve as electron-trapping centers, helping to suppress carrier recombination; simultaneously, their well-defined coordination structure facilitates precise control of O2 adsorption and the reaction energy barriers of key intermediates (such as *OOH), thereby enhancing the 2e- ... - The kinetic selectivity of ORR. Therefore, introducing the SAC concept into the photocatalytic H2O2 system is an important development direction in recent years.

[0005] In the selection of photocatalytic material systems, indium sulfide (In₂S₃) is widely considered a promising visible-light-responsive semiconductor photocatalyst due to its suitable band gap (approximately 2.0-2.3 eV), good visible light absorption, and electron-hole migration characteristics. Furthermore, the sulfur coordination environment of In₂S₃ facilitates strong chemical anchoring with the metal center, making it a good candidate support for constructing stable metal single-atom sites.

[0006] Therefore, there is an urgent need to develop an ideal carrier that can simultaneously achieve (1) strong anchoring of Bi single atoms and (2) effective electronic coupling with Bi. According to the hard-soft acid-base (HSAB) theory, Bi, as a soft acid... 3+ With soft alkali S 2– There is a strong tendency for them to bind together. Therefore, sulfur-containing semiconductor materials are expected to form a more stable Bi-S coordination structure with Bi single atoms, while effectively modulating the frontier orbitals of Bi, thereby improving their photocatalytic activity and selectivity.

[0007] Currently, there is still a need to develop a photocatalytic material that can fully utilize the light absorption advantages of In2S3 and use metal-sulfur interactions to regulate the electronic properties of the active center, so as to achieve efficient, selective and stable H2O2 photocatalytic synthesis. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides an application of an indium sulfide-supported bismuth single-atom composite material in hydrogen peroxide production. This invention loads bismuth (Bi) onto the surface or lattice of In₂S₃, potentially allowing for further modulation of the electronic structure of the catalytic center and improvement of O₂ activation behavior. The 6s / 6p electronic configuration of Bi gives it the potential to modulate the O₂ adsorption configuration and the *OOH intermediate energy barrier. Combined with the visible light absorption characteristics of In₂S₃, this promises to construct a catalyst capable of simultaneously promoting carrier separation and enhancing 2e⁻ activity. - ORR-selective composite photocatalytic system The purpose of this invention is to provide an application of an indium sulfide-supported bismuth single-atom composite material in the production of hydrogen peroxide, wherein the indium sulfide-supported bismuth single-atom composite material comprises indium sulfide and bismuth single atoms supported on the indium sulfide.

[0009] In some embodiments of the present invention, the loading of the bismuth single atom is 0.5 wt.%-10 wt.%.

[0010] In some embodiments of the present invention, the preparation method of the indium sulfide-supported bismuth single-atom composite material includes the following steps: S1. Dissolve an indium source and a sulfur-containing organic compound in water, and heat to carry out a hydrothermal reaction to obtain indium sulfide; S2. The obtained indium sulfide is added to the bismuth source solution for impregnation and stirring reaction to finally obtain the indium sulfide-supported bismuth single-atom composite material precursor; S3, the indium sulfide-supported bismuth single-atom composite material precursor, is calcined in an inert atmosphere to obtain the indium sulfide-supported bismuth single-atom composite material.

[0011] In some embodiments of the present invention, in S1, the indium source is selected from indium chloride and / or indium nitrate; The concentration of the indium source is 5-20 g / L.

[0012] In some embodiments of the present invention, in S1, the molar ratio of the indium source to the sulfur-containing organic compound is 2.0-4.0:1.

[0013] In some embodiments of the present invention, in S1, the sulfur-containing organic compound is selected from one or more of thioacetamide, thiourea, and L-cysteine; The heating temperature is 90-120℃, the heating time is 12-36h, and the heating rate is 5~10℃ / min.

[0014] In some embodiments of the present invention, in S2, the stirring rate is 400~700 rpm and the stirring time is 6-48 h.

[0015] In some embodiments of the present invention, in S2, the bismuth source in the bismuth source solution is selected from bismuth nitrate and / or bismuth chloride; In some embodiments of the present invention, in S2, the concentration of bismuth in the bismuth source solution is 0.05 g / L-1.00 g / L.

[0016] In some embodiments of the present invention, in S2, the mass ratio of indium sulfide to bismuth in the Bi source solution is 1:(0.005-0.1).

[0017] In some embodiments of the present invention, in S3, the calcination conditions are: a heating rate of 5-10℃ / min, a temperature of 200-300℃, and a holding time of 3-6h.

[0018] In some embodiments of the present invention, the inert gas in the inert atmosphere includes nitrogen and / or argon.

[0019] In this invention, the incorporation of bismuth induces significant Bi6s-S3p orbital hybridization. This hybridization narrows the band gap, enhances band dispersion, and generates a polarized interface electronic environment conducive to charge separation and electron transfer. Simultaneously, the Bi-S-In structural unit stabilizes end-face O2 adsorption, preventing the breaking of oxygen-oxygen bonds, thereby guiding the reaction selectively towards 2e-. – The redox pathway converts it to hydrogen peroxide. The indium sulfide support used in this invention has a surface rich in sulfur coordination sites and structural defects; these sites can interact with Bi... 3+ Ions form stable Bi-S coordination bonds. During the impregnation process, Bi... 3+ The ions do not deposit randomly, but preferentially anchor to the aforementioned sites in an isolated coordination form, thereby structurally inhibiting Bi-Bi nucleation and aggregation. The subsequent heat treatment step of heating and calcination is mainly used to remove residual ligands and solidify the Bi-S coordination structure. The temperature is lower than the conditions for Bi species migration and aggregation, and will not lead to the formation of metal nanoparticles.

[0020] The technical solution of the present invention has the following advantages compared with the prior art: (1) The Bi-In2S3 composite catalyst described in this invention has an excellent hydrogen peroxide generation rate under actual catalytic reaction conditions. This is because indium sulfide has a narrow band gap and good visible light absorption performance. In addition, the single-atom bismuth adsorbs oxygen molecules in a Pauling-type configuration, avoiding the breaking of oxygen-oxygen bonds, and has good selectivity for the reduction of oxygen by two electrons, which significantly improves the efficiency of oxygen molecules being activated into hydrogen peroxide.

[0021] (2) The Bi-In2S3 composite catalyst described in this invention has economic benefits and sustainable utilization. This is because the working conditions of this invention do not require organic sacrificial agents, and therefore there is no need to treat the by-products derived from organic sacrificial agents. Secondly, this invention can operate in the visible light range (λ>420nm) without additional energy input, thus having considerable economic benefits and environmental friendliness.

[0022] (3) The Bi-In2S3 composite catalyst described in this invention has excellent long-term catalytic activity (the catalyst can still work after six hours) and recyclability (it still retains more than 90% of its catalytic activity after four cycles). Attached Figure Description

[0023] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein... Figure 1 The image shows the X-ray diffraction pattern of the Bi-In2S3 composite material in Example 1 of this invention.

[0024] Figure 2 The images show the UV-Vis diffuse reflectance (DRS) spectra and corresponding Tauc diagrams of the Bi-In2S3 composite material in Example 1 and the material obtained in Comparative Example 1.

[0025] Figure 3 The photocatalytic hydrogen peroxide production performance of different catalysts in this invention is shown.

[0026] Figure 4 The performance of the Bi-In2S3 composite material in Example 1 of this invention in generating H2O2 after four cycles.

[0027] Figure 5 This demonstrates the long-term H2O2 generation performance of the Bi-In2S3 composite material in Example 1 of this invention.

[0028] Figure 6 This is a comparison of the X-ray diffraction patterns of the Bi-In2S3 composite material before and after the reaction in Example 1 of the present invention. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0030] Example 1 This embodiment provides a method for preparing Bi-In2S3 composite materials and their applications.

[0031] (I) Preparation method of Bi-In2S3 composite material (1) 0.2212 g of anhydrous indium chloride and 0.1500 g of thioacetamide were added to a 100 ml polytetrafluoroethylene-lined hydrothermal reactor containing 40 ml of ultrapure water. After stirring for 30 minutes, the hydrothermal reactor was placed in an oven and heated to 90 °C at a heating rate of 10 °C / min, and reacted for 12 h. After cooling to room temperature, an orange suspension was collected, washed three times with distilled water and ethanol, and then dried overnight under vacuum at 60 °C to obtain indium sulfide material.

[0032] (2) 0.5 g of the indium sulfide material obtained in step (1) was impregnated and dispersed in 50 ml of an aqueous solution of bismuth nitrate, wherein the Bi ion concentration was 1 mg / ml, and then stirred at a stirring rate of 500 rpm for 12 h at room temperature. After the reaction, the orange solid material was collected by centrifugation, washed three times with distilled water and ethanol, and then dried overnight under vacuum at 60 °C to obtain the Bi-In2S3 composite material precursor.

[0033] (3) The Bi-In2S3 composite material precursor was placed in a tube furnace and heated to 250°C at a heating rate of 5°C / min, and held at that temperature for 3 hours. After cooling to room temperature, the Bi-In2S3 composite material was obtained.

[0034] Comparative Example 1 This comparative example uses an In2S3 catalyst without bismuth single atoms as a control, and the preparation method is shown below: 0.2212 g of anhydrous indium chloride and 0.1500 g of thioacetamide were added to a 100 ml polytetrafluoroethylene-lined hydrothermal reactor containing 40 ml of ultrapure water. After stirring for 30 minutes, the hydrothermal reactor was placed in an oven and heated to 90 °C at a rate of 10 °C / min, and reacted for 12 h. After cooling to room temperature, the resulting orange suspension was collected, washed three times with distilled water and ethanol, and then dried overnight under vacuum at 60 °C to obtain indium sulfide material (In₂S₃).

[0035] Structural characterization and performance testing (I) The Bi-In2S3 composite material obtained in Example 1 and the indium sulfide material obtained in Comparative Example 1 were structurally characterized, and the results are shown in the figure. Figure 1 and Figure 2 .

[0036] The X-ray diffraction (XRD) pattern of the Bi-In2S3 composite material obtained in this embodiment is as follows: Figure 1 As shown in Figure a, the diffraction peaks of Example 1 and Comparative Example 1 are highly consistent with the PDF card (PDF#32-0456) of standard In2S3, with sharp peak shapes and no impurity peaks, indicating that the material has good crystallinity. Furthermore, as shown in Figure a... Figure 1 As shown in Figure b, a slight shift in the diffraction peak positions indicates that Bi is incorporated into the intrinsic crystal structure of In₂S₃. This slight change suggests that no phase transformation was induced, and Bi was successfully anchored in In₂S₃ only in a low-content and highly dispersed form. To further refine the local coordination environment of the Bi species, synchrotron X-ray absorption fine structure (XAFS) characterization was performed on the sample. The R-space spectrum obtained after Fourier transform (FT) processing of its extended X-ray absorption fine structure (EXAFS) spectrum is shown below. Figure 1 As shown in Figure c, the Bi-In₂S₃ sample exhibits a significant main coordination peak at approximately 1.57 Å, which can be attributed to the scattering signal of the first coordination shell of the Bi-S. Notably, no scattering peak corresponding to the Bi-Bi bonds in the metallic Bi foil (approximately 2.7 Å) was observed throughout the entire test range, indicating the absence of detectable Bi-Bi interactions in the sample. This result effectively rules out the formation of metallic Bi clusters or nanoparticles, further confirming that Bi species are anchored to the In₂S₃ support surface in the form of isolated atoms. To further investigate the effect of Bi introduction on optical properties, the sample was characterized by absorption spectroscopy. Figure 2 As shown in Figure a, pure In₂S₃ exhibits typical visible light response characteristics, while the absorption edge of the Bi-In₂S₃ sample shows a significant red shift, indicating an enhanced absorption capacity for visible light. This may be due to the alteration of the local electronic structure caused by the introduction of Bi. The bandgap (E) of the sample was determined using the Tauc method. g The calculation is performed using the formula (αhν). 1 / 2 =A(hν-Eg), the result is as follows Figure 2 As shown in Figure b, Bi doping significantly narrows the band gap of In₂S₃ (from 2.06 to 1.84), indicating that Bi-S interaction may lead to band structure redistribution, thereby improving its light-harvesting efficiency. In summary, the introduction of Bi did not affect the crystal structure stability of In₂S₃ and significantly reduced its band gap, enabling Bi-In₂S₃ to exhibit superior photoresponse performance in the visible light range, laying the foundation for further improvements in photocatalytic reactions.

[0037] (II) Photocatalytic H2O2 production experiment and its stability 30 mg of the prepared Bi-In2S3 composite photocatalyst was dispersed in 30 ml of deionized water (the concentration of the Bi-In2S3 composite photocatalyst was...). The catalyst was dispersed ultrasonically for 10 minutes before the reaction in a 50 ml quartz reactor. Then, the reaction system was irradiated at room temperature with a 300W xenon lamp (PCX50C, Beijing Perfect Light Source Technology Co., Ltd.) equipped with a 420 nm cutoff filter (the 420 nm cutoff filter allows only light with wavelengths equal to or greater than 420 nm to pass through, while blocking light with wavelengths less than 420 nm (such as ultraviolet and blue light)). The concentration of H2O2 generated was analyzed by iodometric titration. Typically, 0.5 ml of 0.4 M potassium iodide (KI, purity ≥99%, Aladdin) aqueous solution and 0.5 ml of 0.1 M potassium hydrogen phthalate (purity ≥99.5%, Aladdin) aqueous solution were added to 1 ml of the aqueous phase product and kept for 30 minutes. The absorbance of the mixed solution at 350 nm was then detected using UV-Vis spectroscopy to estimate the amount of H2O2 generated. The mixed solution underwent the following reaction: I3 was generated... − An absorption peak appears near 350 nm. .

[0038] Figure 3 The photocatalytic performance test results of the Bi-In2S3 composite material prepared in Example 1 are presented. It can be clearly seen from the figure that Bi-In2S3 exhibits a significantly enhanced H2O2 generation capacity under visible light irradiation, with a yield reaching 368.8%. Compared to the pure In2S3 used in Comparative Example 1 ( The efficiency was increased by approximately 63.6 times. These results demonstrate that introducing Bi atoms onto In2S3 can effectively regulate its electronic structure and significantly enhance its photocatalytic oxidation capacity, validating the application potential of Bi-In2S3 composite materials in the field of photocatalytic H2O2 generation.

[0039] like Figure 4 and Figure 5 As shown, Bi-In2S3 can stably generate hydrogen peroxide under continuous light irradiation, and the concentration of H2O2 generated during the 6-hour reaction can be maintained at approximately 1300 μM, indicating that the material has good sustained reactivity. Furthermore, in multiple cycle performance tests (a total of four cycles), the H2O2 yield of Bi-In2S3 can still remain above 90%, demonstrating its excellent structural stability and reproducibility in the photocatalytic reaction process.

[0040] Further comparison of the XRD patterns of samples before and after the photocatalytic reaction (e.g.) Figure 6As shown in the figure, the diffraction peak positions and morphology of Bi-In2S3 did not change significantly, and no new impurity phases or signs of crystal structure destruction appeared, which fully demonstrates that the catalyst has good crystal stability under light and reaction environment.

[0041] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. The application of an indium sulfide-supported bismuth single-atom composite material in the production of hydrogen peroxide, characterized in that, The indium sulfide-supported bismuth single-atom composite material includes indium sulfide and bismuth single atoms supported on the indium sulfide.

2. The application according to claim 1, characterized in that, The loading of the bismuth single atom is 0.5 wt.%-10 wt.%.

3. The application according to claim 1, characterized in that, The preparation method of the indium sulfide-supported bismuth single-atom composite material includes the following steps: S1. Dissolve an indium source and a sulfur-containing organic compound in water, and heat to carry out a hydrothermal reaction to obtain indium sulfide; S2. Add the obtained indium sulfide to the bismuth source solution for impregnation and stirring to obtain the indium sulfide-supported bismuth single-atom composite material precursor. S3, the indium sulfide-supported bismuth single-atom composite material precursor, is calcined in an inert atmosphere to obtain the indium sulfide-supported bismuth single-atom composite material.

4. The application according to claim 3, characterized in that, In S1, the indium source is selected from indium chloride and / or indium nitrate; The concentration of the indium source is 5-20 g / L.

5. The application according to claim 3, characterized in that, In S1, the molar ratio of the indium source to the sulfur-containing organic compound is 2.0-4.0:

1.

6. The application according to claim 3, characterized in that, In S1, the sulfur-containing organic compound is selected from one or more of thioacetamide, thiourea, and L-cysteine; The heating temperature is 90-120℃, the heating time is 12-36h, and the heating rate is 5~10℃ / min.

7. The application according to claim 3, characterized in that, In S2, the stirring rate is 400~700 rpm, and the stirring time is 6-48 hours.

8. The application according to claim 3, characterized in that, In S2, the bismuth source in the bismuth source solution is selected from bismuth nitrate and / or bismuth chloride; According to the application of claim 3, in S2, the concentration of bismuth in the bismuth source solution is 0.05 g / L-1.00 g / L; the mass ratio of indium sulfide to bismuth in the bismuth source solution is 1:(0.005-0.1).

9. The application according to claim 3, characterized in that, In S3, the calcination conditions are: heating rate of 5-10℃ / min, temperature of 200-300℃, and holding time of 3-6h.

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