One-step hydrothermal synthesis of carbon-coated zinc sulfide nanowires

Abstract

The application discloses a one-step hydrothermal synthesis method of carbon-coated ZnS nanowires, which uses zinc nitrate and thiourea as precursors, carbon nanotubes as a template and carbon source, and ethylenediamine as a solvent, and directly prepares ZnS nanowires with uniform carbon coating layer by controlling reaction temperature, time and filling degree. The method has the advantages of simple process and low cost, and the obtained product has application potential in photocatalysis and lithium ion battery negative electrode materials.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterial preparation technology, specifically relating to a method for synthesizing carbon-coated zinc sulfide (ZnS) nanowires via a one-step hydrothermal method. Background Technology

[0002] ZnS nanomaterials are widely used in optoelectronic devices, sensors, and energy storage due to their excellent photoelectric properties and catalytic activity. Traditional preparation methods (such as chemical vapor deposition and sol-gel methods) require multiple steps, and carbon coating usually requires an additional high-temperature carbonization process, resulting in high energy consumption and complex processes. This invention proposes a one-step hydrothermal synthesis method that directly generates carbon-coated ZnS nanowires by optimizing the reaction system and conditions, simplifying the process and improving product uniformity. Summary of the Invention

[0003] 1. Technical Solution

[0004] (1) Raw material ratio:

[0005] Zinc nitrate (Zn(NO3)2·6H2O): 1–5 mmol, purity: analytical grade; thiourea (NH2CSNH2): 2–10 mmol, purity: analytical grade; carbon nanotubes: 0.05–0.5 g; solvent ethylenediamine (C2H8N2): 20–50 mL.

[0006] (2) Preparation steps:

[0007] ① Add zinc nitrate, thiourea, and carbon nanotubes to ethylenediamine and ultrasonically disperse for 30 minutes to form a homogeneous mixture; ② Transfer the mixture to a polytetrafluoroethylene-lined reactor, with the filling degree controlled at 70%–85%;

[0008] ③ The hydrothermal reaction was carried out at 180℃ for 12 hours, followed by natural cooling to room temperature;

[0009] ④ The product is washed 3-5 times by centrifugation with anhydrous ethanol and then vacuum dried at 80°C for 6-12 hours.

[0010] 2. Product characteristics

[0011] Nanowire length: 3–10 μm, diameter: 50–80 nm; carbon coating thickness: 15–30 nm; structure: ZnS core layer has a zincblende structure, and the carbon layer is a uniform amorphous coating.

[0012] 3. Innovation Points

[0013] (1) ZnS nucleation and carbon coating are completed simultaneously in one step, with ethylenediamine acting as a solvent, reducing agent and carbon source;

[0014] (2) Carbon nanotubes serve as templates to guide the growth of nanowires and participate in the formation of carbon layers;

[0015] (3) The process is simple, energy consumption is low, and the product morphology is controllable and has good dispersibility. Detailed Implementation

[0016] Example 1

[0017] (1) Mix 2 mmol zinc nitrate, 4 mmol thiourea, 0.1 g carbon nanotubes with 40 mL ethylenediamine;

[0018] (2) After hydrothermal reaction, ZnS nanowires with a length of 5±0.5μm and a diameter of 60±5nm were obtained, and the carbon layer thickness was 20±3nm.

[0019] (3) The core-shell structure was confirmed by electron diffraction and TEM characterization. Figure 3 BET has a specific surface area of ​​120m². 2 / g.

[0020] Example 2

[0021] (1) Adjust the molar ratio of zinc nitrate to thiourea to 1:3, increase carbon nanotubes to 0.3g, increase product diameter to 70nm, and increase carbon layer thickness to 25nm. Attached Figure Description

[0022] Figure 1 and Figure 2 TEM image of ZnS@C nanowires, showing a clear core-shell interface;

[0023] Figure 3 Electron diffraction pattern showing characteristic diffraction of ZnS (JCPDS 05-0566) and amorphous carbon.

Claims

1. A method for preparing carbon-coated ZnS nanowires, characterized in that... Includes the following steps: Zinc nitrate, thiourea, and carbon nanotubes were dispersed in ethylenediamine and subjected to a hydrothermal reaction at 160–200 °C for 10–14 hours. The product was washed and dried to obtain core-shell structured nanowires.

2. The method according to claim 1, characterized in that... The hydrothermal reaction filling degree is 70%–85%.

3. The method according to claim 1, wherein the thickness of the carbon coating layer is 15-30 nm.

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