Preparation method of bismuth oxyiodide-sulfur indium cadmium composite material

Abstract

The invention discloses a preparation method of a bismuth oxyiodide-sulfur indium cadmium composite material, and belongs to the field of inorganic material preparation. The method mainly comprises the following steps: preparing a conical sulfur-indium-cadmium framework; and preparing the bismuth oxyiodide-sulfur-indium-cadmium composite material in situ by taking the conical sulfur-indium-cadmium framework as a template. The preparation method is simple in process and low in cost, the prepared composite material has a large specific surface area and a compact heterojunction interface, and an internal electric field formed in the composite material due to Fermi level difference can efficiently separate photo-generated charges, so that the composite material shows excellent photocatalytic performance and has an application prospect in the fields of environmental restoration and photoelectric devices.

Description

Technical Field

[0001] This invention relates to a method for preparing a bismuth iodide-indium cadmium sulfide composite material, belonging to the field of inorganic nanomaterial preparation. Background Technology

[0002] The photoelectrochemical properties of semiconductor materials, especially the separation and transport efficiency of photogenerated carriers, are crucial to their application prospects in optoelectronic devices. Indium cadmium sulfide (ICS), as a ternary sulfide n-type semiconductor, shows potential in photoelectric conversion due to its excellent visible light absorption characteristics and suitable conduction and valence band energy levels. However, ICS generally faces bottlenecks such as severe recombination of photogenerated carriers and low separation efficiency, resulting in weak macroscopic photoelectric response and limiting its practical application.

[0003] To improve charge separation efficiency, constructing heterojunctions has become an effective technical approach to optimize the photoelectrochemical performance of semiconductors. However, traditional heterojunctions mainly rely on limited band shifts to achieve charge separation, which is insufficient in driving force and makes it difficult to effectively suppress the problem of rapid carrier recombination. At the same time, the interfacial bonding of composite materials is not tight, which easily leads to the formation of interfacial defect states, increasing charge transport resistance and thus affecting photoelectrochemical response efficiency.

[0004] Therefore, constructing pn heterojunctions with strong internal electric fields is an effective strategy to overcome the bottleneck of traditional charge separation. Bismuth oxyiodide, as a typical p-type semiconductor, possesses a unique layered structure that not only provides an efficient directional transport path for charges but also endows the material with excellent visible light trapping capabilities, ensuring a sufficient source of photogenerated carriers. When recombined with n-type indium cadmium sulfide (ILS), the difference in their work functions spontaneously generates a strong internal electric field at the interface, pointing from the ILS region to the bismuth oxyiodide region. This electric field can serve as an efficient internal driving force, enabling efficient spatial separation of carriers and effectively suppressing carrier recombination, thus laying a core foundation for achieving high photoelectrochemical performance.

[0005] Currently, various methods exist for the preparation of bismuth oxyiodide and indium cadmium sulfide, such as high-temperature solid-state methods, ultrasonic synthesis methods, and liquid-phase deposition methods. However, these methods generally suffer from high preparation costs and stringent experimental requirements, making it difficult to meet the application needs of high-performance photoelectrochemical materials. Therefore, developing a simple and controllable preparation process for bismuth oxyiodide-indium cadmium sulfide composite materials that can be grown in situ is a challenging task. Summary of the Invention

[0006] To solve the above technical problems, the present invention is achieved through the following measures: a preparation of a bismuth iodide-indium cadmium sulfide composite material, characterized by comprising the following steps: (1) Preparation of the cone-shaped cadmium indium sulfide framework: First, weigh 0.812 g of cadmium nitrate, 1.6048 g of indium nitrate tetrahydrate, and 1.6232 g of thiourea and dissolve them in 200 mL of ultrapure water. Stir magnetically for 10 min at room temperature to form a uniform precursor suspension. Then, divide the above solution into five 50 mL stainless steel polytetrafluoroethylene-lined autoclaves and react at 200°C for 8-10 h. After the autoclaves have cooled naturally to room temperature, collect all the solid products in the autoclaves, combine them, and wash them thoroughly with deionized water and anhydrous ethanol in sequence. Then, dry them at 60°C to obtain the cone-shaped cadmium indium sulfide framework, as shown in the attached figure. Figure 1 As shown; (2) Using the cone-shaped cadmium indium sulfide framework obtained in step (1) as a template, prepare bismuth oxysulfate-cadmium sulfide composite material: Weigh 0.9701 g of bismuth nitrate pentahydrate, 0.3320 g of potassium iodide, and 0.9406 g of the cone-shaped cadmium indium sulfide obtained in step (1) and disperse them in 30 mL of ethylene glycol. After stirring magnetically at room temperature for 60 min, a growth solution is obtained. Then, it is transferred to a 50 mL stainless steel polytetrafluoroethylene-lined autoclave and baked at 160 °C for 4 h. After the reaction is completed, the autoclave is cooled to room temperature, and the obtained product is collected by centrifugation. It is washed several times with deionized water and anhydrous ethanol, and dried at 60 °C overnight to obtain the bismuth oxysulfate-cadmium sulfide composite material, as shown in the attached figure. Figure 2 As shown. The superior results of this invention

[0007] (1) The method has a simple and efficient synthesis route, avoids complex post-processing, and has significant cost-effectiveness.

[0008] (2) The bismuth oxyiodide-cadmium sulfide composite material prepared by this method inherits the large specific surface area and abundant pores of the cone-shaped skeleton, and at the same time constructs a multi-level pore structure, which greatly increases the number of active sites.

[0009] (3) The intrinsic electric field formed by the Fermi level difference of the bismuth iodide-indium cadmium sulfide composite material effectively drives the spatial separation of electron-hole pairs, thereby greatly improving its photocatalytic performance.

[0010] (4) The present invention uses a template-induced in-situ growth strategy to enable bismuth iodide oxide and cadmium indium sulfide to form a tight interface bond, thereby constructing an efficient heterojunction charge transport channel, which synergistically enhances the light absorption capacity and further strengthens the synergistic enhancement effect of photocatalytic performance. Attached Figure Description

[0011] Figure 1 Scanning electron microscope image of the cone-shaped indium cadmium sulfide skeleton.

[0012] Figure 2Scanning electron microscope image of bismuth iodide-cadmium indium sulfide composite material. Detailed Implementation

[0013] To better understand the present invention, the following specific embodiments further illustrate the content of the present invention, but the present invention is not limited to the following embodiments. Example 1

[0014] (1) Preparation of the cone-shaped indium cadmium sulfide framework: First, weigh 0.812 g of cadmium nitrate, 1.6048 g of indium nitrate tetrahydrate, and 1.6232 g of thiourea and dissolve them in 200 mL of ultrapure water. Stir magnetically for 10 min at room temperature to form a uniform precursor suspension. Then, divide the above solution into five 50 mL stainless steel polytetrafluoroethylene-lined autoclaves and react at 200°C for 8 h. After the autoclaves have cooled naturally to room temperature, collect all the solid products in the autoclaves, combine them, and wash them thoroughly with deionized water and anhydrous ethanol in sequence. Then, dry them at 60°C to obtain the cone-shaped indium cadmium sulfide framework, as shown in the attached figure. Figure 1 As shown; (2) Using the cone-shaped cadmium indium sulfide framework obtained in step (1) as a template, prepare bismuth oxysulfate-cadmium sulfide composite material: Weigh 0.9701 g of bismuth nitrate pentahydrate, 0.3320 g of potassium iodide, and 0.9406 g of the cone-shaped cadmium indium sulfide obtained in step (1) and disperse them in 30 mL of ethylene glycol. After stirring magnetically at room temperature for 60 min, a growth solution is obtained. Then, it is transferred to a 50 mL stainless steel polytetrafluoroethylene-lined autoclave and baked at 160 °C for 4 h. After the reaction is completed, the autoclave is cooled to room temperature, and the obtained product is collected by centrifugation. It is washed several times with deionized water and anhydrous ethanol, and dried at 60 °C overnight to obtain bismuth oxysulfate-cadmium sulfide, as shown in the attached figure. Figure 2 As shown. Example 2

[0015] The preparation steps are the same as in Example 1, except that the reaction is carried out at 200 °C for 9 h in step (1). Example 3

[0016] The preparation steps are the same as in Example 1, except that the reaction is carried out at 200 °C for 10 h in step (1).

Claims

1. A method for preparing a bismuth oxyiodide-cadmium indium sulfide composite material, characterized by the following steps: (1) Preparation of cone-shaped indium cadmium sulfide framework: First, weigh 0.812 g of cadmium nitrate, 1.6048 g of indium nitrate tetrahydrate and 1.6232 g of thiourea and dissolve them in 200 mL of ultrapure water. Stir magnetically for 10 min at room temperature to form a uniform precursor suspension. Then, divide the above solution into five 50 mL stainless steel polytetrafluoroethylene lined autoclaves and react at 200°C for 8-10 h. After the autoclaves cool naturally to room temperature, collect all the solid products in the autoclaves, combine them and wash them thoroughly with deionized water and anhydrous ethanol in sequence, and dry them at 60°C to obtain the cone-shaped indium cadmium sulfide framework. (2) Using the cone-shaped cadmium sulfide skeleton obtained in step (1) as a template, prepare bismuth oxysulfide-cadmium sulfide composite material: Weigh 0.9701 g of bismuth nitrate pentahydrate, 0.3320 g of potassium iodide, and 0.9406 g of the cone-shaped cadmium sulfide obtained in step (1) and disperse them in 30 mL of ethylene glycol. After stirring magnetically at room temperature for 60 min, a growth solution is obtained. Then, it is transferred to a 50 mL stainless steel polytetrafluoroethylene-lined autoclave and baked at 160 °C for 4 h. After the reaction is completed, wait for the autoclave to cool to room temperature, collect the obtained product by centrifugation, wash it several times with deionized water and anhydrous ethanol, and dry it overnight at 60 °C to obtain bismuth oxysulfide-cadmium sulfide composite material.

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