Sea urchin-shaped bismuth sulfide light absorption material as well as preparation method and application thereof

Abstract

The invention provides a sea urchin-shaped bismuth sulfide light absorption material as well as a preparation method and application thereof, and belongs to the technical field of inorganic materials. Compared with the existing commercially available bismuth hydroxide dispersion liquid, the preparation method has the advantages that the bismuth source dispersion liquid containing the bismuth hydroxide precipitate is firstly prepared, so that the microstructure and the surface property of the bismuth hydroxide precipitate can be regulated and controlled, and subsequent generation of urchin-shaped bismuth sulfide is facilitated. The dispersing agent is added into the bismuth source dispersion liquid, uniform dispersion of bismuth hydroxide can be promoted, and the particle uniformity of the final product sea urchin-shaped bismuth sulfide is guaranteed. The sulfide solution is added into the bismuth source dispersion liquid for precipitation reaction, the obtained precipitate is amorphous or spherical bismuth sulfide particles, the bismuth sulfide particles are subsequently mixed with dilute nitric acid, the pH value of the precipitation reaction liquid is adjusted to be 1.8-2.0, acidification treatment is carried out under the condition of mechanical stirring, the dynamic catalysis effect can be achieved, and the preparation method is simple and easy to implement. The transformation of amorphous or spherical bismuth sulfide particles to urchin-shaped bismuth sulfide is promoted.

Description

Technical Field

[0001] The present invention relates to the technical field of inorganic materials, and in particular to a sea urchin-shaped bismuth sulfide light-absorbing material, a preparation method thereof, and applications thereof. Background Art

[0002] Bismuth sulfide is a typical semiconductor material with excellent optoelectronic properties and is widely used in infrared detectors, photocatalysts, and thermoelectric materials. However, traditional bismuth sulfide is often prepared using simple co-precipitation, high-temperature solid-phase, hydrothermal, or solvothermal methods, which lack the ability to control morphology. The resulting bismuth sulfide has certain limitations in terms of particle uniformity, purity, and optical properties, and cannot meet the material requirements of high-performance infrared detectors. Summary of the Invention

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

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions: The present invention provides a method for preparing a sea urchin-shaped bismuth sulfide light-absorbing material, 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 a bismuth hydroxide precipitate, separating the bismuth hydroxide precipitate, and 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; The precipitation reaction liquid is mixed with dilute nitric acid, the pH value of the precipitation reaction liquid is adjusted to 1.8-2.0, and re-acidification treatment is performed under mechanical stirring to obtain a sea urchin-shaped bismuth sulfide light absorbing material.

[0005] Preferably, the bismuth source includes one or more of bismuth nitrate, bismuth chloride, bismuth hydroxide and bismuth acid; The inorganic acid includes nitric acid and / or hydrogen chloride; After the bismuth source, the inorganic acid and the first solvent are mixed, the pH value of the obtained mixed solution is 0.8-2.3.

[0006] Preferably, the alkali solution is NaOH and / or ammonia water; the pH value of the alkali solution containing bismuth hydroxide precipitate is 6.5-7.8.

[0007] Preferably, the dispersant includes one or more of polyvinyl pyrrolidone, polyacrylic acid and sodium dodecylbenzene sulfonate; 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 %.

[0008] Preferably, 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.

[0009] Preferably, the precipitation reaction temperature is 95-135° C., and the time is 12-24 hours.

[0010] Preferably, the temperature of the re-acidification treatment is 85-100°C and the time is 2-3 hours; The mechanical stirring speed is 1800-2200 rpm.

[0011] Preferably, the first solvent, the second solvent and the third solvent are independently one or more of water, ethanol and isopropanol.

[0012] The present invention provides a sea urchin-shaped bismuth sulfide light-absorbing material prepared by the above preparation method.

[0013] The present invention provides the use of the sea urchin-shaped bismuth sulfide light absorption material as an infrared detection material, a photocatalytic material or a thermoelectric material.

[0014] The present invention provides a method for preparing a sea urchin-shaped bismuth sulfide light-absorbing material, 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 a 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 carry out a precipitation reaction to obtain a precipitation reaction solution; mixing the precipitation reaction solution with dilute nitric acid, adjusting the pH of the precipitation reaction solution to 1.8-2.0, and re-acidifying the solution under mechanical stirring to obtain a sea urchin-shaped bismuth sulfide light-absorbing material. The present invention first prepares a bismuth source dispersion containing a bismuth hydroxide precipitate. Compared to existing commercially available bismuth hydroxide dispersions, the present invention can control the micromorphology and surface properties of the bismuth hydroxide precipitate, facilitating the subsequent production of sea urchin-shaped bismuth sulfide. The addition of a dispersant to the bismuth source dispersion promotes uniform dispersion of the bismuth hydroxide, ensuring uniform particle size of the final sea urchin-shaped bismuth sulfide product. The present invention adds a sulfide solution to the bismuth source dispersion to carry out a precipitation reaction. The resulting precipitate is amorphous or spherical bismuth sulfide particles. Through the subsequent addition of a dilute nitric acid solution, the acidic environment provided by the nitric acid can effectively induce surface reconstruction of the particles and promote directional crystal growth, ultimately forming an "urchin-like" structure with spike-like protrusions, which exhibits more excellent infrared light absorption performance.

[0015] The sea urchin-shaped bismuth sulfide light absorption material prepared by the present invention has high purity, uniform particle size, and good optical absorption performance. The particle size is 0.4-0.6 μm, the purity is ≥99.98%, and the absorption rate in the 8-14 μm infrared band is greater than 90%. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a scanning electron microscope image of the bismuth sulfide particles obtained in Example 4; Figure 2 is a scanning electron microscope image of the bismuth sulfide particles obtained in Comparative Example 1; Figure 3 This is a scanning electron microscope image of the bismuth sulfide particles obtained in Comparative Example 2. DETAILED DESCRIPTION

[0017] The present invention provides a method for preparing a sea urchin-shaped bismuth sulfide light-absorbing material, 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 a bismuth hydroxide precipitate, separating the bismuth hydroxide precipitate, and 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; The precipitation reaction liquid is mixed with dilute nitric acid, the pH value of the precipitation reaction liquid is adjusted to 1.8-2.0, and re-acidification treatment is performed under mechanical stirring to obtain a sea urchin-shaped bismuth sulfide light absorbing material.

[0018] The present invention combines a bismuth source, an inorganic acid, and a first solvent, and then mixes the resulting mixture with an alkaline solution to produce an alkaline solution containing a bismuth hydroxide precipitate. In the present 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 bismuthic acid (Bi₂O₃), more preferably bismuth nitrate. In the present invention, the inorganic acid preferably includes nitric acid and / or hydrogen chloride. After mixing the bismuth source, inorganic acid, and first solvent, the resulting mixture preferably has a pH of 0.8 to 2.3, more preferably 1 to 2. The present invention has no specific requirements for the concentration or amount of the inorganic acid added; it suffices to ensure that the resulting bismuth solution has a pH of 0.8 to 2.3.

[0019] In the present invention, the first solvent preferably includes one or more of water, ethanol and isopropanol, more preferably water. The present invention has no special requirements for the mixing method, and a mixing method well known to those skilled in the art can be used, such as stirring and mixing.

[0020] In the present invention, the alkali solution is NaOH and / or aqueous ammonia. The pH of the alkali solution containing the bismuth hydroxide precipitate is preferably 6.5 to 7.8, more preferably 7 to 7.5. The present invention has no particular requirements for the concentrations of the NaOH and aqueous ammonia, as long as the pH of the resulting alkali solution containing the bismuth hydroxide precipitate is within a range of 6.5 to 7.8.

[0021] After obtaining an alkaline solution containing a bismuth hydroxide precipitate, the present invention separates the bismuth hydroxide precipitate and mixes the bismuth hydroxide precipitate, a dispersant, and a 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.

[0022] In the present invention, the second solvent preferably includes one or more of water, ethanol, and isopropanol, more preferably water. In the present invention, the dispersant preferably includes one or more of polyvinyl pyrrolidone, polyacrylic acid, and sodium dodecylbenzenesulfonate. In the present invention, the bismuth source dispersion is preferably a suspension of bismuth hydroxide precipitate. 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 the present invention, the concentration of the dispersant is preferably 0.3-1.0 wt%, more preferably 0.5-0.8 wt%. The present invention enhances particle dispersibility and morphological stability by washing the bismuth hydroxide precipitate, redispersing it, and adding a dispersant, such as polyvinyl pyrrolidone (PVP), preferably at a mass concentration of 0.3-1.0 wt%. In the present invention, the dispersant forms an adsorption layer in the initial presence of bismuth ions, facilitating subsequent uniform nucleation and "sea urchin-like" spiny growth.

[0023] The present invention combines a sulfur source and a third solvent to produce 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), with sodium thiosulfate being more preferred. In this invention, sodium thiosulfate, due to its relatively stable solubility and reaction temperature range, can effectively control the reaction selectivity and reduce the occurrence of side reactions. Sodium sulfide and hydrogen sulfide, due to their high reactivity, are suitable for process systems that require a short reaction time. In this invention, the third solvent preferably includes one or more of water, ethanol, and isopropanol, with water being more preferred.

[0024] The present invention has no particular requirements for the mixing method; any mixing method known to those skilled in the art may be used, such as stirring. In the present invention, the concentration of the sulfide solution is preferably 0.02 to 1.2 mol / L, more preferably 0.05 to 0.5 mol / L, and even more preferably 0.1 to 0.3 mol / L.

[0025] In the present invention, the sulfide solution is added to the bismuth source dispersion to undergo a precipitation reaction, thereby obtaining a precipitation reaction solution. In the present 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 sulfide addition rate and solution concentration, the size and distribution of the resulting bismuth sulfide particles can be precisely controlled. At this stage, the reaction rate and temperature significantly influence the crystallinity and morphology of the particles.

[0026] In the present invention, the temperature of the precipitation reaction is preferably 95-135°C, more preferably 100-120°C; the time is preferably 12-24 hours, more preferably 16-20 hours. As a specific embodiment of the present invention, the reaction formula of the precipitation reaction is preferably: 2Bi(NO3)3+3Na2S2O3+3H2O→Bi2S3+6NaNO3+3H2SO4.

[0027] In this method, the reaction system temperature should be between 95°C and 135°C as the sulfide solution is slowly added to the bismuth solution. This temperature range not only facilitates the precipitation of bismuth sulfide but also prevents side reactions and solution instability that could 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 between 16 and 24 hours to ensure complete reaction and sufficient product crystallization.

[0028] The present invention mixes the precipitation reaction liquid with dilute nitric acid, adjusts the pH value of the precipitation reaction liquid to 1.8-2.0, and performs a re-acidification treatment under mechanical stirring conditions to obtain a sea urchin-shaped bismuth sulfide light absorbing material. In the present invention, the mass concentration of the dilute nitric acid is preferably 5-10%. In the present invention, the temperature of the re-acidification treatment is preferably 85-100°C, more preferably 90-95°C, and the time is preferably 2-3 hours. In the present invention, the rate of the mechanical stirring is preferably 1800-2200 rpm, more preferably 2000 rpm. The re-acidification treatment under mechanical stirring conditions of the present invention can maintain the particles in a uniform suspension state, promote impurity dissolution and interface purification, effectively induce particle surface reconstruction and promote directional crystal growth, and ultimately form a "sea urchin-like" structure with spike-like protrusions, showing better infrared light absorption performance.

[0029] After the re-acidification reaction, the present invention preferably performs post-treatment on the obtained re-acidification reaction liquid, and the post-treatment preferably includes solid-liquid separation, washing, and drying performed in sequence. In the present invention, the solid-liquid separation is preferably centrifugation or filtration, more preferably centrifugation. In the present invention, the centrifugation rate is preferably 1000-3000 rpm, more preferably 1000-2500 rpm, and even more preferably 2200 rpm; and the time is preferably 10-15 minutes. In the present invention, when separating particles of smaller particle size, it is generally necessary to use a higher centrifugation rate (e.g., 2200 rpm) and set the centrifugation time to 10-15 minutes to ensure efficient separation and concentration of the particles.

[0030] In the present invention, the washing agent used in the washing is preferably water and / or ethanol. In the present invention, the washing is preferably multiple washings, the number of washings is preferably 2 to 5 times, and the time for a single washing is preferably 10 to 15 minutes.

[0031] In the present invention, the drying temperature is preferably 50-120°C, more preferably 70-90°C, to avoid morphological changes or structural damage to the particles caused by excessively high temperatures. In the present invention, the drying time is preferably 4-8 hours, more preferably 6 hours. During the drying process, the sample should be regularly stirred or turned to ensure uniform drying of the particles and prevent aggregation. During the drying process, care should be taken to avoid excessive aggregation or sintering of the particles.

[0032] After drying, the dried product is preferably ground and ultrasonically dispersed. A planetary ball mill is preferably used for grinding, using stainless steel or ceramic balls as the grinding media. The grinding time is 2 to 4 hours, more preferably 3 hours. The grinding speed is preferably 200 to 500 rpm, more preferably 300 to 400 rpm, to control the particle size and distribution. Smaller particles require the use of smaller grinding media and an appropriately longer grinding time.

[0033] In the present invention, the ultrasonic dispersion power is preferably 50 to 200 W, more preferably 100 to 150 W, the frequency is preferably 20 to 40 kHz, more preferably 30 kHz, and the duration is preferably 10 to 30 minutes, more preferably 20 minutes. The present invention controls the ultrasonic dispersion conditions to ensure that the particles are fully dispersed and that aggregation between the particles is prevented.

[0034] The present invention provides a sea urchin-shaped bismuth sulfide light-absorbing material prepared by the above-described preparation method. In the present invention, the sea urchin-shaped bismuth sulfide light-absorbing material preferably has a particle size of 0.4 to 0.6 μm and a purity of ≥99.98%. The sea urchin-shaped bismuth sulfide light-absorbing material obtained by the present invention has an absorptivity greater than 90% in the infrared band at wavelengths between 8 and 14 μm.

[0035] The present invention provides the use of the sea urchin-shaped bismuth sulfide light absorption material as an infrared detection material, a photocatalytic material or a thermoelectric material.

[0036] The sea urchin-shaped bismuth sulfide light absorbing material provided by the present invention, its preparation method and application are described in detail below with reference to the examples, but they should not be construed as limiting the scope of protection of the present invention.

[0037] Example 1 ①Prepare bismuth solution: Mix 10.0 g of Bi(NO₃)₃·5H₂O (0.0206 mol), 2.0 mL of 1 M HNO₃, and 50 mL of deionized water to obtain a mixture with a pH of approximately 1. This mixture was then mixed with 50 mL of 1 M NaOH solution, causing the pH of the reaction system to rapidly rise to 6.5–7.0, generating a large amount of white, flocculent bismuth hydroxide precipitate.

[0038] The above bismuth hydroxide precipitate was centrifuged and washed (to remove NO3 - 、Na + After removing impurities (such as bismuth hydroxide), the precipitate was redispersed in 100 mL of deionized water. 1.0 g of polyvinylpyrrolidone (PVP) was added and thoroughly ultrasonically dispersed to obtain a bismuth source dispersion. The concentration of the bismuth hydroxide precipitate was 0.0206 mol / 100 mL (0.206 M), and the concentration of the polyvinylpyrrolidone was 1.0 g / 160 mL (0.625 wt%).

[0039] ②Prepare sulfide solution: Dissolve 7.6 g of Na2S2O3·5H2O in 100 mL of deionized water to obtain 0.3 M S2O3 2- No additional pH adjustment is required.

[0040] ③Precipitation reaction 100 mL of sulfide solution was added to 100 mL of bismuth solution at a rate of 0.8 mL / min. A precipitation reaction was carried out at 95-100°C. The reaction system was carried out under continuous stirring to ensure uniform mixing of bismuth ions and sulfide ions. After 16 hours of reaction, a precipitation reaction solution was obtained.

[0041] ④ Re-acidification treatment The precipitation reaction solution was mixed with 10 mL of 5% wt dilute nitric acid, and the pH value of the resulting mixture was 1.9-2.0. The mixture was re-acidified under mechanical stirring (2000 rpm) at 95° C. for 2.5 h.

[0042] ⑤ Post-processing After the reaction, the resulting re-acidified solution was centrifuged (2000 rpm, 15 min) and washed several times with deionized water to remove unreacted impurities. The resulting precipitate was then dried at 80°C for 6 h. The resulting powder was then milled in a planetary ball mill (350 rpm) for 3 h and subjected to ultrasonic dispersion (120 W, 30 kHz) for 20 min.

[0043] Experimental results show that the prepared sea urchin-shaped bismuth sulfide powder has a particle size of 0.4 to 0.45 μm, a 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 reveals that the powder exhibits excellent infrared absorption properties with an absorptivity exceeding 90% in the 8-14 μm band.

[0044] Example 2 ①Prepare bismuth solution: 6.5 g BiCl3, 1.5 mL 1 M HNO3 and 50 mL deionized water were mixed to obtain a mixture with a pH of 1.2; the mixture was mixed with 50 mL 1 M NaOH solution to obtain a mixture with a pH of 6.8, generating an alkaline solution containing bismuth hydroxide precipitate.

[0045] After the bismuth hydroxide precipitate was separated, it was mixed with 1.0 g of polyacrylic acid (PAA) and 100 mL of deionized water to obtain a bismuth source dispersion.

[0046] The concentration of bismuth hydroxide precipitate is 0.20 mol / L, and the concentration of the dispersant is 1.0 wt%.

[0047] ②Prepare sulfide solution: Dissolve 1.5g of sodium sulfide (Na2S) in 50mL of ethanol to obtain 0.38MS 2- No additional pH adjustment is required.

[0048] ③Precipitation reaction 50 mL of sulfide solution was added to 100 mL of bismuth solution at a rate of 0.8 mL / min. A precipitation reaction was carried out at 115°C. The reaction system was stirred continuously to ensure uniform mixing of bismuth ions and sulfide ions. After 20 h of reaction, a precipitation reaction solution was obtained. ④ Re-acidification treatment The precipitation reaction solution was mixed with 8 mL of 5 wt % dilute nitric acid to obtain a mixture with a pH of 1.8. The mixture was re-acidified under mechanical stirring (2000 rpm) at 95° C. for 2 h.

[0049] ⑤ Post-processing After the reaction, the resulting re-acidification solution was centrifuged (2000 rpm, 10 min) and washed multiple times with deionized water and ethanol to remove unreacted impurities. The resulting precipitate was then dried at 90°C for 6 h. The resulting powder was milled in a planetary ball mill (350 rpm) for 3 h and then subjected to ultrasonic dispersion (120 W power, 30 kHz frequency) for 20 min.

[0050] Experimental results show that the bismuth sulfide powder prepared by this method has a particle size of approximately 0.5 to 0.55 μm and a purity exceeding 99.99%. Optical tests show that its absorption rate in the 8-12 μm band reaches 75% to 80%, demonstrating high stability and absorption capacity.

[0051] Example 3 ①Prepare bismuth solution: Mix 5.2 g Bi(OH)3 (about 0.020 mol), 2.0 mL 1 M HNO3, and 60 mL deionized water to obtain a mixture with a pH of 2.0; The resulting mixture was mixed with 30 mL of 0.5 M NaOH solution, and the pH value of the resulting mixture was 6.5, generating an alkaline solution containing bismuth hydroxide precipitate; After the bismuth hydroxide precipitate is separated, it is mixed with 0.5 g of sodium dodecylbenzenesulfonate (SDS) and 100 mL of deionized water to obtain a bismuth source dispersion.

[0052] The concentration of bismuth hydroxide precipitate is 0.20 mol / L, and the concentration of the dispersant is 0.5 wt%.

[0053] ②Prepare sulfide solution: Dissolve 1.28 g of sulfur (S) in 80 mL of ethanol to obtain a 0.5 M sulfide solution without additional pH adjustment.

[0054] ③Precipitation reaction 80 mL of sulfide solution was added to 120 mL of bismuth solution at a rate of 1.0 mL / min. A precipitation reaction was carried out at 130°C. The reaction system was stirred continuously to ensure uniform mixing of bismuth ions and sulfide ions. After 14 hours of reaction, a precipitation reaction solution was obtained. ④ Re-acidification treatment The precipitation reaction solution was mixed with 10 mL of 5 wt % dilute nitric acid to obtain a mixture with a pH of 2.0. The mixture was re-acidified under mechanical stirring (2000 rpm) at 95° C. for 3 h.

[0055] ⑤ Post-processing After the reaction, the resulting re-acidified solution was centrifuged (2000 rpm, 15 minutes) and washed several times with deionized water to remove unreacted impurities. The resulting precipitate was then dried at 70°C for 6 hours. The resulting powder was then milled in a planetary ball mill (at 400 rpm) for 3 hours and subjected to ultrasonic dispersion (100 W power, 30 kHz frequency) for 20 minutes.

[0056] Experimental results show that the final product has a particle size of 0.55 to 0.6 μm and a purity of 99.95%. Although XRD results show that the crystallization rate is close to that of the product heated to 95°C to 100°C, the optical absorption performance is reduced, with an absorption rate of 65% to 70% in the 6-8 μm band.

[0057] Example 4 The difference between Example 4 and Example 1 is that the temperature and time of the precipitation reaction are different from those of Example 1, and the other operations are the same. The specific differences are shown in Table 1.

[0058] In Example 4, X-ray diffraction (XRD) analysis showed that the bismuth sulfide particles prepared under these conditions achieved optimal crystallinity, with a uniform particle size of 0.35 μm to 0.4 μm. Optical testing revealed that the powder's infrared absorptivity in the 8-14 μm band reached 95%, exceeding the 90% observed in Example 1.

[0059] Figure 1 This is a scanning electron microscope image of the bismuth sulfide particles obtained in Example 4. Scanning electron microscope (SEM) observation shows that the particles have a smooth surface and a regular crystal morphology, showing significant high-quality crystal characteristics.

[0060] Comparative Examples 1 and 2 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, and the other operations are the same. The specific differences are shown in Table 1.

[0061] The raw material types, reaction conditions and properties of the obtained products of Examples 1-4 and Comparative Examples 1-2 are shown in Table 1.

[0062] Table 1 Types of raw materials, reaction conditions and properties of the obtained products of Examples 1-4 and Comparative Examples 1-2 Figure 2 is a scanning electron microscope image of the bismuth sulfide particles obtained in Comparative Example 1, Figure 3 This is a scanning electron microscope image of the bismuth sulfide particles obtained in Comparative Example 2.

[0063] In Comparative Example 1, the particle size of the obtained particles was approximately 0.4 μm to 0.5 μm, and the crystallization rate was significantly lower than that of the product prepared at 95°C to 100°C. The infrared absorption rate was only 50% to 55%, and the particle distribution uniformity was poor.

[0064] In Comparative Example 2, the particle size of the resulting particles increased significantly to 0.7 μm to 0.8 μm, but the crystal structure did not show significant improvement. The optical absorption performance was poor, with an absorptivity of only 60% to 65% in the 8-14 μm band.

[0065] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a sea urchin-shaped bismuth sulfide light-absorbing material, characterized in that: The following steps are involved: 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 a bismuth hydroxide precipitate, separating the bismuth hydroxide precipitate, and 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; The precipitation reaction liquid is mixed with dilute nitric acid, the pH value of the precipitation reaction liquid is adjusted to 1.8-2.0, and re-acidification treatment is performed under mechanical stirring to obtain a sea urchin-shaped bismuth sulfide light absorbing material.

2. The preparation method according to claim 1, characterized in that The bismuth source includes one or more of bismuth nitrate, bismuth chloride, bismuth hydroxide and bismuth acid; The inorganic acid includes nitric acid and / or hydrogen chloride; After the bismuth source, the inorganic acid and the first solvent are mixed, the pH value of the obtained mixed solution is 0.8-2.

3.

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

8.

4. The preparation method according to claim 1, characterized in that The dispersant includes one or more of polyvinyl pyrrolidone, polyacrylic acid and sodium dodecylbenzene sulfonate; 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 %.

5. 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.

6. The preparation method according to claim 1 or 5, characterized in that The precipitation reaction temperature is 95-135° C. and the time is 2-3 hours.

7. The preparation method according to claim 1, characterized in that The re-acidification treatment temperature is 85-100°C and the time is 2-3 hours; The mechanical stirring speed is 1800-2200 rpm.

8. 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.

9. The sea urchin-shaped bismuth sulfide light-absorbing material prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the sea urchin-shaped bismuth sulfide light absorption material according to claim 9 as an infrared detection material, a photocatalytic material or a thermoelectric material.

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