A sea urchin-shaped bismuth sulfide light-absorbing material and its preparation method and application

Abstract

This invention provides a sea urchin-shaped bismuth sulfide light-absorbing material, its preparation method, and its application, belonging to the field of inorganic materials technology. The invention first prepares a bismuth source dispersion containing bismuth hydroxide precipitate. Compared to existing commercially available bismuth hydroxide dispersions, this invention can control the microstructure and surface properties of the bismuth hydroxide precipitate, which is beneficial for the subsequent formation of sea urchin-shaped bismuth sulfide. The invention adds a dispersant to the bismuth source dispersion to promote the uniform dispersion of bismuth hydroxide and ensure the uniformity of the final product, sea urchin-shaped bismuth sulfide particles. The invention adds a sulfide solution to the bismuth source dispersion to carry out a precipitation reaction. The resulting precipitate consists of amorphous or spherical bismuth sulfide particles. Subsequent mixing with dilute nitric acid to adjust the pH of the precipitation reaction solution to 1.8-2.0, followed by re-acidification under mechanical stirring, provides a dynamic catalytic effect, promoting the transformation of amorphous or spherical bismuth sulfide particles into sea urchin-shaped bismuth sulfide.

Description

Technical Field

[0001] This invention relates to the field of inorganic materials technology, specifically to a sea urchin-shaped bismuth sulfide light-absorbing material, its preparation method, and its application. Background Technology

[0002] Bismuth sulfide is a typical semiconductor material, widely used in infrared detectors, photocatalysts, and thermoelectric materials due to its excellent photoelectric properties. However, traditional bismuth sulfide preparation methods, such as simple co-precipitation, high-temperature solid-state methods, hydrothermal methods, or solvothermal methods, lack morphology control capabilities. The resulting bismuth sulfide exhibits limitations in particle uniformity, purity, and optical properties, failing to meet the material requirements of high-performance infrared detectors. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide a sea urchin-shaped bismuth sulfide light-absorbing material, its preparation method, and its applications. The sea urchin-shaped bismuth sulfide light-absorbing material prepared by this invention has good dispersibility, high specific surface area, and excellent infrared absorption performance.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] This invention provides a method for preparing a sea urchin-shaped bismuth sulfide light-absorbing material, comprising the following steps:

[0006] A bismuth source, an inorganic acid, and a first solvent are mixed. The resulting mixture is then mixed with an alkaline solution to obtain an alkaline solution containing bismuth hydroxide precipitate. The bismuth hydroxide precipitate is separated. The bismuth hydroxide precipitate, a dispersant, and a second solvent are then mixed to obtain a bismuth source dispersion.

[0007] The sulfur source and the third solvent are mixed to obtain a sulfide solution;

[0008] The sulfide solution was added to the bismuth source dispersion to carry out a precipitation reaction, resulting in a precipitation reaction solution.

[0009] The precipitate reaction solution was mixed with dilute nitric acid, and the pH of the precipitate reaction solution was adjusted to 1.8~2.0. The solution was then subjected to re-acidification under mechanical stirring to obtain a sea urchin-shaped bismuth sulfide light-absorbing material.

[0010] Preferably, the bismuth source includes one or more of bismuth nitrate, bismuth chloride, bismuth hydroxide, and bismuth acid;

[0011] The inorganic acid includes nitric acid and / or hydrogen chloride;

[0012] The pH value of the mixture obtained after mixing the bismuth source, inorganic acid and first solvent is 0.8~2.3.

[0013] Preferably, the alkaline solution is NaOH and / or ammonia; the pH value of the alkaline solution containing bismuth hydroxide precipitate is 6.5~7.8.

[0014] Preferably, the dispersant comprises one or more of polyvinylpyrrolidone, polyacrylic acid, and sodium dodecylbenzenesulfonate;

[0015] The concentration of bismuth hydroxide precipitate in the bismuth source dispersion is 0.03~0.8 mol / L, and the concentration of dispersant is 0.3~1.0 wt%.

[0016] Preferably, the sulfur source includes one or more of sodium sulfate, ammonium sulfate, sodium sulfide, sulfur, and hydrogen sulfide;

[0017] The concentration of the sulfide solution is 0.02~1.2 mol / L.

[0018] Preferably, the precipitation reaction is carried out at a temperature of 95~135℃ for 12~24h.

[0019] Preferably, the re-acidification treatment is performed at a temperature of 85~100℃ for 2~3 hours.

[0020] The mechanical stirring speed is 1800~2200 rpm.

[0021] Preferably, the first solvent, the second solvent, and the third solvent are independently one or more of water, ethanol, and isopropanol.

[0022] This invention provides a urchin-shaped bismuth sulfide light-absorbing material prepared by the above-described method.

[0023] This invention provides the application of the above-mentioned urchin-shaped bismuth sulfide light-absorbing material as an infrared detection material, photocatalytic material, or thermoelectric material.

[0024] This invention provides a method for preparing a bismuth sulfide light-absorbing material resembling sea urchin precipitate, comprising the following steps: mixing a bismuth source, an inorganic acid, and a first solvent; mixing the resulting mixture with an alkaline solution to obtain an alkaline solution containing bismuth hydroxide precipitate; separating the bismuth hydroxide precipitate; mixing the bismuth hydroxide precipitate, a dispersant, and a second solvent to obtain a bismuth source dispersion; mixing a sulfur source and a third solvent to obtain a sulfide solution; adding the sulfide solution to the bismuth source dispersion to perform a precipitation reaction to obtain a precipitation reaction solution; mixing the precipitation reaction solution with dilute nitric acid to adjust the pH of the precipitation reaction solution to 1.8-2.0; and performing a re-acidification treatment under mechanical stirring to obtain the bismuth sulfide light-absorbing material resembling sea urchin precipitate. This invention first prepares a bismuth source dispersion containing bismuth hydroxide precipitate. Compared with existing commercially available bismuth hydroxide dispersions, this invention can control the microstructure and surface properties of the bismuth hydroxide precipitate, which is beneficial to the subsequent formation of bismuth sulfide resembling sea urchin precipitate. This invention adds a dispersant to the bismuth source dispersion to promote the uniform dispersion of bismuth hydroxide and ensure the particle uniformity of the final product, bismuth sulfide resembling sea urchin precipitate. In this invention, a sulfide solution is added to the bismuth source dispersion to carry out a precipitation reaction. The resulting precipitate consists of amorphous or spherical bismuth sulfide particles. With the subsequent addition of dilute nitric acid solution, the acidic environment provided by the nitric acid can effectively induce particle surface reconstruction and promote crystal directional growth, ultimately forming a "sea urchin-like" structure with spiked protrusions, exhibiting superior infrared light absorption performance.

[0025] The urchin-shaped bismuth sulfide light-absorbing material prepared by this invention has high purity and uniform particle size, and has good optical absorption performance. Its particle size is 0.4~0.6μm, purity ≥99.98%, and absorption rate is greater than 90% in the 8~14μm infrared band. Attached Figure Description

[0026] Figure 1 Here is a scanning electron microscope image of the bismuth sulfide particles obtained in Example 4;

[0027] Figure 2 Scanning electron microscope image of bismuth sulfide particles obtained in Comparative Example 1;

[0028] Figure 3 The image shows a scanning electron microscope (SEM) image of the bismuth sulfide particles obtained in Comparative Example 2. Detailed Implementation

[0029] This invention provides a method for preparing a sea urchin-shaped bismuth sulfide light-absorbing material, comprising the following steps:

[0030] A bismuth source, an inorganic acid, and a first solvent are mixed. The resulting mixture is then mixed with an alkaline solution to obtain an alkaline solution containing bismuth hydroxide precipitate. The bismuth hydroxide precipitate is separated. The bismuth hydroxide precipitate, a dispersant, and a second solvent are then mixed to obtain a bismuth source dispersion.

[0031] The sulfur source and the third solvent are mixed to obtain a sulfide solution;

[0032] The sulfide solution was added to the bismuth source dispersion to carry out a precipitation reaction, resulting in a precipitation reaction solution.

[0033] The precipitate reaction solution was mixed with dilute nitric acid, and the pH of the precipitate reaction solution was adjusted to 1.8~2.0. The solution was then subjected to re-acidification under mechanical stirring to obtain a sea urchin-shaped bismuth sulfide light-absorbing material.

[0034] This invention involves mixing a bismuth source, an inorganic acid, and a first solvent, then mixing the resulting mixture with an alkaline solution to obtain an alkaline solution containing bismuth hydroxide precipitate. In this invention, the bismuth source preferably includes one or more of bismuth nitrate (Bi(NO3)3·5H2O), bismuth chloride (BiCl3), bismuth hydroxide (Bi(OH)3), and bismuth acid (Bi2O3), more preferably bismuth nitrate. In this invention, the inorganic acid preferably includes nitric acid and / or hydrogen chloride. After mixing the bismuth source, inorganic acid, and first solvent, the pH value of the resulting mixture is preferably 0.8~2.3, more preferably 1~2. This invention does not have special requirements regarding the concentration and amount of the inorganic acid, as long as the pH value of the resulting bismuth solution is maintained at 0.8~2.3.

[0035] In this invention, the first solvent preferably includes one or more of water, ethanol, and isopropanol, more preferably water. This invention does not impose any special requirements on the mixing method; any mixing method well-known to those skilled in the art can be used, such as stirring.

[0036] In this invention, the alkaline solution is NaOH and / or ammonia; the pH value of the alkaline solution containing bismuth hydroxide precipitate is preferably 6.5-7.8, more preferably 7-7.5. This invention does not have special requirements for the concentration of the NaOH and ammonia, as long as the pH value of the resulting alkaline solution containing bismuth hydroxide precipitate is maintained at 6.5-7.8.

[0037] After obtaining an alkaline solution containing bismuth hydroxide precipitate, the present invention separates the bismuth hydroxide precipitate, and mixes the bismuth hydroxide precipitate, dispersant, and second solvent to obtain a bismuth source dispersion. In the present invention, the method for separating the bismuth hydroxide precipitate preferably includes: washing the alkaline solution containing the bismuth hydroxide precipitate and performing solid-liquid separation, wherein the washing is preferably water washing, and the solid-liquid separation is preferably centrifugation or filtration.

[0038] In this invention, the second solvent preferably includes one or more of water, ethanol, and isopropanol, more preferably water. In this invention, the dispersant preferably includes one or more of polyvinylpyrrolidone, polyacrylic acid, and sodium dodecylbenzenesulfonate. In this invention, the bismuth source dispersion is preferably a suspension of bismuth hydroxide precipitate, and the concentration of the bismuth hydroxide precipitate in the bismuth source dispersion is preferably 0.03~0.8 mol / L, more preferably 0.06~0.6 mol / L, and even more preferably 0.1~0.4 mol / L. In this invention, the concentration of the dispersant is preferably 0.3~1.0 wt%, more preferably 0.5~0.8 wt%. This invention enhances particle dispersibility and morphological stability by washing and redispersing the bismuth hydroxide precipitate and adding a dispersant such as polyvinylpyrrolidone (PVP), preferably at a mass concentration of 0.3~1.0 wt%. In this invention, the dispersant forms an adsorption layer at the initial presence of bismuth ions, which is beneficial for subsequent uniform nucleation and "sea urchin-like" spiny growth.

[0039] This invention mixes a sulfur source and a third solvent to obtain a sulfide solution. In this invention, the sulfur source preferably includes one or more of sodium thiosulfate (Na₂S₂O₃·5H₂O), sodium sulfide (Na₂S), sulfur (S), and hydrogen sulfide (H₂S), more preferably sodium thiosulfate. In this invention, sodium thiosulfate, due to its relatively stable solubility and reaction temperature range, can better control the selectivity of the reaction and reduce the occurrence of side reactions; while sodium sulfide and hydrogen sulfide, due to their strong reactivity, are suitable for process systems where the reaction is completed in a short time. In this invention, the third solvent preferably includes one or more of water, ethanol, and isopropanol, more preferably water.

[0040] The present invention does not have any special requirements for the mixing method; any mixing method well known to those skilled in the art can be used, such as stirring. In the present invention, the concentration of the sulfide solution is preferably 0.02~1.2 mol / L, more preferably 0.05~0.5 mol / L, and even more preferably 0.1~0.3 mol / L.

[0041] In this invention, the sulfide solution is added to the bismuth source dispersion to induce a precipitation reaction, yielding a precipitated reaction solution. In this invention, the molar ratio of the bismuth source to the sulfur source is preferably 1:1.5~4, more preferably 1:2~3. The addition rate of the sulfide solution is preferably 0.5~1.2 mL / min, more preferably 0.8~1.0 mL / min. By controlling the addition rate of the sulfide and the solution concentration, this invention can precisely regulate the size and distribution of the generated bismuth sulfide particles. During this stage, the reaction rate and temperature have a significant impact on the crystallinity and morphology of the particles.

[0042] In this invention, the temperature of the precipitation reaction is preferably 95~135℃, more preferably 100~120℃; the time is preferably 12~24h, more preferably 16~20h. As a specific embodiment of this invention, the preferred reaction formula for the precipitation reaction is:

[0043] 2Bi(NO3)3+3Na2S2O3+3H2O→Bi2S3+6NaNO3+3H2SO4.

[0044] In this invention, when the sulfide solution is slowly added to the bismuth solution, the temperature of the reaction system should be between 95°C and 135°C. This temperature range not only facilitates the precipitation of bismuth sulfide but also prevents side reactions or solution instability that may occur at excessively high temperatures. During the reaction, bismuth ions and sulfide ions rapidly combine to form amorphous or spherical bismuth sulfide (Bi₂S₃) particles. The reaction time is typically controlled at 16–24 hours to ensure complete reaction and sufficient product crystallization.

[0045] This invention involves mixing the precipitation reaction solution with dilute nitric acid, adjusting the pH of the precipitation reaction solution to 1.8-2.0, and then subjecting it to re-acidification under mechanical stirring to obtain a sea urchin-like bismuth sulfide light-absorbing material. In this invention, the mass concentration of the dilute nitric acid is preferably 5-10%. The re-acidification temperature is preferably 85-100℃, more preferably 90-95℃, and the time is preferably 2-3 hours. The mechanical stirring rate is preferably 1800-2200 rpm, more preferably 2000 rpm. This invention, by performing the re-acidification under mechanical stirring, maintains the particles in a uniform suspension state, promotes impurity dissolution and interface purification, effectively induces particle surface reconstruction and promotes directional crystal growth, ultimately forming a "sea urchin-like" structure with spiked protrusions, exhibiting superior infrared light absorption performance.

[0046] Following the re-acidification reaction, the present invention preferably performs post-treatment on the resulting re-acidification reaction solution. The post-treatment preferably includes sequential solid-liquid separation, washing, and drying. In this invention, the solid-liquid separation is preferably centrifugation or filtration, more preferably centrifugation. In this invention, the centrifugation rate is preferably 1000-3000 rpm, more preferably 1000-2500 rpm, and even more preferably 2200 rpm; the centrifugation time is preferably 10-15 min. In this invention, when separating particles with smaller diameters, a higher centrifugation rate (e.g., 2200 rpm) is typically required, with a centrifugation time set to 10-15 min to ensure efficient separation and concentration of the particles.

[0047] In this invention, the washing agent used is preferably water and / or ethanol. In this invention, the washing is preferably performed multiple times, preferably 2 to 5 times, and the duration of each wash is preferably 10 to 15 minutes.

[0048] In this invention, the drying temperature is preferably 50~120℃, more preferably 70~90℃, to avoid excessively high temperatures causing morphological changes or structural damage to the particles. The drying time is preferably 4~8 hours, more preferably 6 hours. During the drying process, the sample needs to be stirred or turned regularly to ensure uniform drying of the particles and prevent particle aggregation. Care should be taken to avoid excessive particle aggregation or sintering during the drying process.

[0049] After drying, the dried product is preferably ground and ultrasonically dispersed. A planetary ball mill is preferably used for grinding, with stainless steel or ceramic balls as the grinding media, for a grinding time of 2-4 hours, more preferably 3 hours; the grinding speed is preferably 200-500 rpm, more preferably 300-400 rpm, to control the particle size and distribution. Smaller particles require smaller grinding media and a longer grinding time.

[0050] In this invention, the power of the ultrasonic dispersion is preferably 50-200W, more preferably 100-150W, the frequency is preferably 20-40kHz, more preferably 30kHz, and the time is preferably 10-30min, more preferably 20min. This invention ensures that the particles are fully dispersed and do not aggregate by controlling the conditions of ultrasonic dispersion.

[0051] This invention provides a urchin-shaped bismuth sulfide light-absorbing material prepared by the above-described method. In this invention, the particle size of the urchin-shaped bismuth sulfide light-absorbing material is preferably 0.4~0.6 μm, and the purity is preferably ≥99.98%. The urchin-shaped bismuth sulfide light-absorbing material obtained by this invention has a particle size of 8~14 μm and an infrared absorption rate greater than 90%.

[0052] This invention provides the application of the above-mentioned urchin-shaped bismuth sulfide light-absorbing material as an infrared detection material, photocatalytic material, or thermoelectric material.

[0053] The following detailed description, in conjunction with embodiments, illustrates the urchin-shaped bismuth sulfide light-absorbing material, its preparation method, and its applications provided by the present invention. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0054] Example 1

[0055] ①Preparation of bismuth solution:

[0056] 10.0 g Bi(NO3)3·5H2O (0.0206 mol), 2.0 mL 1 M HNO3 and 50 mL deionized water were mixed to obtain a mixture with a pH of about 1. The resulting mixture was then mixed with 50 mL 1 M NaOH solution, and the pH of the reaction system rapidly increased to 6.5~7.0, generating a large amount of white flocculent bismuth hydroxide precipitate.

[0057] The above bismuth hydroxide precipitate was washed by centrifugation (to remove NO3). - Na + After removing impurities, the mixture was redispersed in 100 mL of deionized water, and 1.0 g of polyvinylpyrrolidone (PVP) was added. After thorough ultrasonic dispersion, a bismuth source dispersion was obtained. The concentration of bismuth hydroxide precipitate was 0.0206 mol / 100 mL = 0.206 M; the concentration of polyvinylpyrrolidone was 1.0 g / 160 mL = 0.625 wt%.

[0058] ②Preparation of sulfide solution:

[0059] Dissolving 7.6 g of Na₂S₂O₃·5H₂O in 100 mL of deionized water yields 0.3 M Na₂S₂O₃. 2- The solution does not require additional pH adjustment.

[0060] ③Precipitation reaction

[0061] 100 mL of sulfide solution was added to 100 mL of bismuth solution at a rate of 0.8 mL / min. The precipitation reaction was carried out at 95-100 °C with continuous stirring to ensure uniform mixing of bismuth ions and sulfide ions. After 16 h of reaction, the precipitated reaction solution was obtained.

[0062] ④ Re-acidification treatment

[0063] The precipitate reaction solution was mixed with 10 mL of 5%wt dilute nitric acid, and the resulting mixture had a pH of 1.9 to 2.0. The mixture was then subjected to re-acidification treatment under mechanical stirring (2000 rpm) at a temperature of 95°C for 2.5 h.

[0064] ⑤ Post-processing

[0065] After the reaction was completed, the resulting re-acidified reaction solution was centrifuged (2000 rpm, 15 min) and washed repeatedly with deionized water to remove unreacted impurities. Subsequently, the precipitate was dried at 80°C for 6 h, and the resulting powder was ground in a planetary ball mill (350 rpm) for 3 h and then ultrasonically dispersed (120 W, 30 kHz) for 20 min.

[0066] Experimental results show that the prepared urchin-shaped bismuth sulfide powder has a particle size of 0.4 μm to 0.45 μm, uniform particle distribution, and a purity exceeding 99.98%. X-ray diffraction (XRD) results indicate a complete crystal structure and high crystallinity. Infrared spectroscopy analysis shows that the powder exhibits excellent infrared absorption performance with an absorption rate exceeding 90% in the 8–14 μm wavelength range.

[0067] Example 2

[0068] ①Preparation of bismuth solution:

[0069] Mix 6.5g BiCl3, 1.5mL 1M HNO3 and 50mL deionized water to obtain a mixture with a pH of 1.2; mix the resulting mixture with 50mL 1M NaOH solution to obtain a mixture with a pH of 6.8, generating an alkaline solution containing bismuth hydroxide precipitate.

[0070] After separating the bismuth hydroxide precipitate, it was mixed with 1.0 g of polyacrylic acid (PAA) and 100 mL of deionized water to obtain a bismuth source dispersion.

[0071] The concentration of bismuth hydroxide precipitate was 0.20 mol / L, and the concentration of dispersant was 1.0 wt%.

[0072] ②Preparation of sulfide solution:

[0073] Dissolving 1.5 g of sodium sulfide (Na₂S) in 50 mL of ethanol yields 0.38 MS. 2- The solution does not require additional pH adjustment.

[0074] ③Precipitation reaction

[0075] 50 mL of sulfide solution was added to 100 mL of bismuth solution at a rate of 0.8 mL / min. The precipitation reaction was carried out at 115 °C with continuous stirring to ensure uniform mixing of bismuth ions and sulfide ions. After 20 h of reaction, the precipitated reaction solution was obtained.

[0076] ④ Re-acidification treatment

[0077] The precipitate reaction solution was mixed with 8 mL of 5 wt% dilute nitric acid, and the resulting mixture had a pH of 1.8. The mixture was then subjected to re-acidification treatment under mechanical stirring (2000 rpm) at a temperature of 95°C for 2 hours.

[0078] ⑤ Post-processing

[0079] After the reaction was completed, the resulting re-acidification reaction solution was centrifuged (2000 rpm, 10 min) and washed repeatedly with deionized water and ethanol to remove unreacted impurities. Subsequently, the precipitate was dried at 90°C for 6 h, and the resulting powder was ground in a planetary ball mill (350 rpm) for 3 h and then ultrasonically dispersed (120 W power, 30 kHz frequency) for 20 min.

[0080] Experimental results show that the bismuth sulfide powder prepared by this method has a particle size of approximately 0.5 μm to 0.55 μm and a purity higher than 99.99%. Optical tests show that its absorption rate reaches 75% to 80% in the 8–12 μm wavelength range, exhibiting high stability and absorption capacity.

[0081] Example 3

[0082] ①Preparation of bismuth solution:

[0083] Mix 5.2g Bi(OH)3 (approximately 0.020mol), 2.0mL 1M HNO3 and 60mL deionized water to obtain a mixture with a pH of 2.0.

[0084] The resulting mixture was mixed with 30 mL of 0.5 M NaOH solution, and the pH of the resulting mixture was 6.5, producing an alkaline solution containing bismuth hydroxide precipitate.

[0085] After separating the bismuth hydroxide precipitate, it was mixed with 0.5 g sodium dodecylbenzenesulfonate (SDS) and 100 mL deionized water to obtain a bismuth source dispersion.

[0086] The concentration of bismuth hydroxide precipitate was 0.20 mol / L, and the concentration of dispersant was 0.5 wt%.

[0087] ②Preparation of sulfide solution:

[0088] Dissolve 1.28 g of sulfur (S) in 80 mL of ethanol to obtain a 0.5 M sulfide solution without additional pH adjustment.

[0089] ③Precipitation reaction

[0090] 80 mL of sulfide solution was added to 120 mL of bismuth solution at a rate of 1.0 mL / min. The precipitation reaction was carried out at 130 °C with continuous stirring to ensure uniform mixing of bismuth ions and sulfide ions. After 14 h of reaction, the precipitated reaction solution was obtained.

[0091] ④ Re-acidification treatment

[0092] The precipitate reaction solution was mixed with 10 mL of 5 wt% dilute nitric acid, and the resulting mixture had a pH of 2.0. The mixture was then subjected to re-acidification treatment under mechanical stirring (2000 rpm) at a temperature of 95°C for 3 hours.

[0093] ⑤ Post-processing

[0094] After the reaction was completed, the resulting re-acidified solution was centrifuged (2000 rpm, 15 min) and washed repeatedly with deionized water to remove unreacted impurities. Subsequently, the precipitate was dried at 70°C for 6 h, and the resulting powder was ground in a planetary ball mill (400 rpm) for 3 h and then ultrasonically dispersed (100 W, 30 kHz) for 20 min.

[0095] Experimental results show that the particle size of the final product is 0.55 μm to 0.6 μm, and the purity reaches 99.95%. Although XRD results show that its crystallinity is close to that under conditions of 95℃ to 100℃, its optical absorption performance is reduced, with an absorption rate of 65% to 70% in the 6~8 μm band.

[0096] Example 4

[0097] The difference between Example 4 and Example 1 is that the temperature and time of the precipitation reaction are different from those in Example 1, while the rest of the operations are the same. The specific differences are shown in Table 1.

[0098] In Example 4, X-ray diffraction (XRD) analysis showed that the bismuth sulfide particles prepared under these conditions achieved optimal crystallinity, with a particle size of 0.35 μm to 0.4 μm and uniform distribution. Optical testing showed that the powder's infrared absorption rate in the 8–14 μm wavelength range reached 95%, higher than the 90% in Example 1.

[0099] Figure 1 This is a scanning electron microscope (SEM) image of the bismuth sulfide particles obtained in Example 4. SEM observation shows that the particles have smooth surfaces and regular crystal morphology, exhibiting significant high-quality crystal characteristics.

[0100] Comparative Examples 1-2

[0101] The difference between Comparative Examples 1 and 2 and Example 1 is that the temperature and time of the precipitation reaction are different from those in Example 1, while the other operations are the same. The specific differences are shown in Table 1.

[0102] The types of raw materials, reaction conditions, and properties of the products obtained in Examples 1-4 and Comparative Examples 1-2 are shown in Table 1.

[0103] Table 1. Types of raw materials, reaction conditions, and properties of the products obtained in Examples 1-4 and Comparative Examples 1-2.

[0104]

[0105] Figure 2 For comparison, here are scanning electron microscope images of the bismuth sulfide particles obtained in Example 1. Figure 3 The image shows a scanning electron microscope (SEM) image of the bismuth sulfide particles obtained in Comparative Example 2.

[0106] In Comparative Example 1, the resulting particles had a diameter of approximately 0.4 μm to 0.5 μm, and a crystallinity significantly lower than that of the product obtained under conditions of 95°C to 100°C. The infrared absorption rate was only 50% to 55%, and the particle distribution uniformity was poor.

[0107] In Comparative Example 2, the particle size increased significantly to 0.7 μm–0.8 μm, but the crystal structure did not show significant improvement. Optical absorption performance was poor, with an absorption rate of only 60%–65% in the 8–14 μm wavelength range.

[0108] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a urchin-shaped bismuth sulfide light-absorbing material, characterized in that, Includes the following steps: A bismuth source, an inorganic acid, and a first solvent are mixed. The resulting mixture is then mixed with an alkaline solution to obtain an alkaline solution containing bismuth hydroxide precipitate. The bismuth hydroxide precipitate is separated. The bismuth hydroxide precipitate, a dispersant, and a second solvent are mixed to obtain a bismuth source dispersion. The bismuth source includes one or more of bismuth nitrate, bismuth chloride, and bismuth hydroxide. The inorganic acid includes nitric acid and / or hydrogen chloride. The dispersant includes one or more of polyvinylpyrrolidone, polyacrylic acid, and sodium dodecylbenzenesulfonate. The concentration of bismuth hydroxide precipitate in the bismuth source dispersion is 0.03~0.8 mol / L, and the concentration of the dispersant is 0.3~1.0 wt%. The sulfur source and the third solvent are mixed to obtain a sulfide solution; The sulfide solution is added to the bismuth source dispersion to carry out a precipitation reaction, thereby obtaining a precipitation reaction solution; the precipitation reaction is carried out at a temperature of 95~135℃ for 12~24h. The precipitate reaction solution is mixed with dilute nitric acid, and the pH value of the precipitate reaction solution is adjusted to 1.8~2.

0. Under mechanical stirring, it is re-acidified to obtain urchin-shaped bismuth sulfide light-absorbing material. The temperature of the re-acidification treatment is 85~100℃, the time is 2~3h, and the mechanical stirring speed is 1800~2200rpm.

2. The preparation method according to claim 1, characterized in that, The pH value of the mixture obtained after mixing the bismuth source, inorganic acid and first solvent is 0.8~2.

3.

3. The preparation method according to claim 1, characterized in that, The alkaline solution is NaOH and / or ammonia; the pH value of the alkaline solution containing bismuth hydroxide precipitate is 6.5~7.

8.

4. The preparation method according to claim 1, characterized in that, The sulfur source includes one or more of sodium sulfate, ammonium sulfate, sodium sulfide, sulfur, and hydrogen sulfide; The concentration of the sulfide solution is 0.02~1.2 mol / L.

5. The preparation method according to claim 1, characterized in that, The first solvent, the second solvent, and the third solvent are independently one or more of water, ethanol, and isopropanol.

6. The urchin-shaped bismuth sulfide light-absorbing material prepared by the preparation method according to any one of claims 1 to 5.

7. The application of the urchin-shaped bismuth sulfide light-absorbing material according to claim 6 as an infrared detection material, photocatalytic material, or thermoelectric material.

Images