Preparation method of carbon nanotube confined one-dimensional cobalt-doped molybdenum disulfide

Abstract

This invention discloses a method for synthesizing one-dimensional cobalt-doped molybdenum disulfide confined within carbon nanotubes. The embodiments of this invention provide a method for synthesizing one-dimensional cobalt-doped molybdenum disulfide (Co-MoS2@SWCNT) confined within carbon nanotubes. The preparation method of the carbon nanotube-confined one-dimensional cobalt-doped molybdenum disulfide precursor involves mixing Anderson-type Co polyacid with single-walled carbon nanotubes in water and stirring. Through charge transfer and capillary action between the carbon nanotubes and the Co polyacid, the Co polyacid is embedded within the carbon nanotubes. The precursor is then reacted with high-purity sulfur in a tube furnace under an argon and hydrogen atmosphere to prepare cobalt-doped molybdenum disulfide powder with embedded carbon nanotubes.

Description

Technical Field

[0001] This invention relates to the field of nanomaterials science and engineering, specifically to a method for preparing one-dimensional cobalt-doped molybdenum disulfide confined within carbon nanotubes. Background Technology

[0002] Molybdenum disulfide (MoS2), a typical transition metal chalcogenide, has shown broad application prospects in energy catalysis, photoelectric detection, and energy storage devices due to its unique layered structure, excellent electron transport properties, and good chemical stability. However, pure-phase molybdenum disulfide has inherent defects such as a limited number of active sites and insufficient electronic conductivity, which restricts its performance improvement and industrial application. Transition metal doping has been proven to be an effective strategy for optimizing the electronic structure of molybdenum disulfide and enhancing its catalytic activity. Among them, cobalt (Co) doping can significantly improve its catalytic efficiency in hydrogen evolution reaction (HER) and sulfur reduction reaction (SRR) by regulating the electron density of anions (S) and inducing spin-polarized electron directional transfer, and has clear application value.

[0003] The dimensional control of low-dimensional materials is key to discovering their novel physicochemical properties. One-dimensional molybdenum disulfide can further enhance charge separation and transport efficiency due to the quantum confinement effect. However, traditional top-down (such as mechanical exfoliation) or bottom-up (such as vapor deposition) synthesis methods are difficult to accurately prepare thermodynamically stable one-dimensional molybdenum disulfide structures and are prone to agglomeration, which seriously affects the performance of the material.

[0004] Carbon nanotubes, as an ideal one-dimensional confined carrier, can construct unique nanoreactors with their atomically smooth inner walls and adjustable diameters. Through spatial confinement effects and interfacial electrostatic interactions, they force guest materials to grow along a one-dimensional direction, while endowing the materials with excellent conductivity and structural stability. This effectively solves the problems of structural control and agglomeration in the preparation of low-dimensional materials.

[0005] Therefore, developing a method for preparing one-dimensional cobalt-doped molybdenum disulfide confined within carbon nanotubes to achieve synergistic optimization of the material's dimensional structure and electronic properties is of great significance for overcoming the performance bottlenecks of existing molybdenum disulfide-based materials and expanding their applications in high-end energy and electronic devices. However, current preparation techniques still suffer from problems such as complex processes and poor controllability of product morphology and composition. Therefore, finding a method for preparing one-dimensional cobalt-doped molybdenum disulfide confined within carbon nanotubes is essential. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing one-dimensional cobalt-doped molybdenum disulfide confined in carbon nanotubes, which aims to achieve the preparation of one-dimensional cobalt-doped molybdenum disulfide confined in carbon nanotubes through liquid phase filling method and tube furnace sulfidation post-treatment.

[0007] This invention proposes a method for preparing a cobalt polyacid embedded carbon nanotube precursor. The preparation method involves mixing and stirring Anderson-type cobalt polyacid, open carbon nanotubes, and deionized water to prepare the aforementioned nanotube-confined one-dimensional cobalt-doped molybdenum disulfide precursor.

[0008] The present invention also proposes a method for preparing one-dimensional cobalt-doped molybdenum disulfide confined in carbon nanotubes, wherein the preparation method is a post-sulfurization treatment in a tube furnace.

[0009] The beneficial effects of the method for preparing one-dimensional cobalt-doped molybdenum disulfide confined within carbon nanotubes provided by this invention are as follows: It uses cobalt polyacid, carbon nanotubes, and deionized water as raw materials to form cobalt polyacid-embedded carbon nanotubes via a liquid-phase method. Then, a tubular furnace sulfidation post-treatment converts the cobalt polyacid within the carbon nanotubes into cobalt-doped molybdenum disulfide. Attached Figure Description

[0010] The following is a brief explanation of the content depicted in the accompanying drawings:

[0011] Figure 1 This is a schematic diagram illustrating the principle of preparing cobalt-doped molybdenum disulfide embedded carbon nanotubes in an embodiment of the present invention.

[0012] Figure 2 These are TEM and EDS images of the cobalt polyacid-embedded carbon nanotubes prepared in the embodiments of the present invention.

[0013] Figure 3 XPS image of cobalt polyacid embedded carbon nanotubes prepared in the embodiments of the present invention;

[0014] Figure 4 These are TEM and EDS images of cobalt-doped molybdenum disulfide embedded carbon nanotubes prepared in the embodiments of the present invention.

[0015] Figure 5 This is a high-resolution aberration image of cobalt-doped molybdenum disulfide embedded carbon nanotubes prepared in the embodiments of the present invention.

[0016] Figure 6 XPS image of molybdenum disulfide-embedded carbon nanotubes prepared in the embodiments of the present invention; Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0018] The following is a detailed description of the preparation method of cobalt polyacid embedded carbon nanotubes and carbon nanotube confined one-dimensional cobalt-doped molybdenum disulfide provided in the embodiments of the present invention.

[0019] This invention provides a method for preparing one-dimensional cobalt-doped molybdenum disulfide confined within carbon nanotubes. Please refer to [the provided text]. Figure 1 It includes the following steps:

[0020] (1) Preparation of cobalt polyacid embedded carbon nanotubes: 1.1 Opening treatment of carbon nanotubes: Weigh 100 mg of Tuball single-walled carbon nanotube powder with a tube diameter of less than or equal to 2 nm, place it in a quartz boat, and then place it in a CVD furnace. Anneal at 550 °C in air atmosphere for 2 to 4 h to obtain open Tuball single-walled carbon nanotubes. 1.2 Preparation of supersaturated cobalt polyacid solution: At room temperature, weigh cobalt polyacid to water at a ratio of 20-50 mg / mL, and sonicate to completely dissolve cobalt polyacid in water. 1.3 Cobalt Polyacid Embedded Carbon Nanotubes: A magnetic stir bar was added to the above-mentioned cobalt polyacid supersaturated solution, and then open carbon nanotubes were weighed and added to the cobalt polyacid solution. The ratio of carbon nanotubes to the cobalt polyacid supersaturated solution was 3-5 mg / mL. The mixture was stirred at room temperature for 3-4 days on a magnetic stirrer at a speed of 800-1000 rpm. The sample was then washed and dried, and the resulting product was cobalt polyacid embedded carbon nanotubes.

[0021] (2) Preparation of one-dimensional cobalt-doped molybdenum disulfide confined within carbon nanotubes: The product is obtained by sulfidation of cobalt polyacid with embedded carbon nanotubes. High-purity sulfur is placed on a tube furnace, and the cobalt polyacid with embedded carbon nanotubes is located in the central heating zone of the tube furnace. The calcination temperature is 120-800℃, preferably 350-550℃, and the calcination time is 2-3 hours. The flow ratio of argon to hydrogen is 10-100:1-20, preferably 50-80:10-20.

[0022] Example 1 This invention provides a method for preparing one-dimensional cobalt-doped molybdenum disulfide confined within carbon nanotubes, comprising the following steps:

[0023] (1) At room temperature, 400 mg of cobalt polyacid ((NH4)3[CoMo6O24H6]·7H2O) was dissolved in 15 mL of deionized water, and then 45 mg of open carbon nanotubes were added to the above solution. The mixture was placed on a stirring table and stirred at 800 rpm for 3 days. The reacted sample was filtered and washed, and the resulting powder was cobalt polyacid-embedded carbon nanotubes (CoMo6@SWCNT).

[0024] (2) Place the CoMo6@SWCNT prepared in (1) in the central heating zone of a tube furnace, place high-purity sulfur upstream, and set the argon to hydrogen flow rate ratio to 80:10. Calcine at 500℃ for 2 hours. The resulting powder is carbon nanotube-confined one-dimensional cobalt-doped molybdenum disulfide.

[0025] Example 2 This embodiment provides a method for preparing one-dimensional cobalt-doped molybdenum disulfide confined within carbon nanotubes. The only difference from Example 1 is the adjustment of the following parameters: the ratio of cobalt polyacid to solvent is 25 mg / mL, the ratio of carbon nanotubes to supersaturated cobalt polyacid solution is 3 mg / mL, the flow ratio of argon to hydrogen is 50:10, and the calcination temperature is 350℃.

[0026] Example 3 This embodiment provides a method for preparing one-dimensional cobalt-doped molybdenum disulfide confined in carbon nanotubes. The only difference from Example 1 is the adjustment of the following parameters: the ratio of cobalt polyacid to solvent is 50 mg / mL, the ratio of carbon nanotubes to supersaturated cobalt polyacid solution is 5 mg / mL, the flow ratio of argon to hydrogen is 80:20, and the calcination temperature is 550℃.

[0027] Example 4 The present invention provides a method for preparing one-dimensional cobalt-doped molybdenum disulfide confined in carbon nanotubes. The only difference from the method in Example 1 is the adjustment of the following parameters: the ratio of cobalt polyacid to solvent is 40 mg / mL, the ratio of carbon nanotubes to supersaturated cobalt polyacid solution is 4 mg / mL, the flow ratio of argon to hydrogen is 60:15, and the calcination temperature is 450°C.

[0028] Example 5 The present invention provides a method for preparing one-dimensional cobalt-doped molybdenum disulfide confined in carbon nanotubes. The only difference from the method in Example 1 is the adjustment of the following parameters: the ratio of cobalt polyacid to solvent is 20 mg / mL, the ratio of carbon nanotubes to supersaturated cobalt polyacid solution is 3 mg / mL, the flow ratio of argon to hydrogen is 50:10, and the calcination temperature is 400℃.

[0029] Experimental Example 1 The TEM and EDS images of CoMo6@SWCNTs prepared in Example 1 are shown below. Figure 2 XPS spectrum can be found Figure 3 TEM and EDS images of the carbon nanotube-confined one-dimensional cobalt-doped molybdenum disulfide prepared in Example 1 are shown below. Figure 4 High-resolution spherical aberration diagram can be found Figure 5 XPS chart Figure 6 .

[0030] from Figure 2The TEM and EDS images show that the cobalt-doped embedded carbon nanotubes were successfully synthesized, and uniform and large-area filling can be seen inside the carbon nanotubes.

[0031] Figure 3 The XPS plot shows that the elemental binding energy increases after cobalt and molybdenum are embedded, confirming that the mechanism of cobalt polyacid embedding carbon nanotubes is charge transfer between the carbon nanotubes and the cobalt polyacid. The XPS results show that only cobalt and molybdenum are present as metallic elements.

[0032] Figure 4 The TEM image shows that the carbon nanotubes prepared in this application successfully confine one-dimensional cobalt-doped molybdenum disulfide sulfur element into the carbon nanotubes with high efficiency.

[0033] Figure 5 The high-resolution spherical aberration image shows that the carbon nanotube-confined one-dimensional cobalt-doped molybdenum disulfide prepared in this application was successfully synthesized, with cobalt doping in the molybdenum disulfide.

[0034] Figure 6 The XPS plot shows that the characteristic peaks at 228.5 eV and 231.7 eV in Mo correspond to the characteristic peaks at 231.7 eV in Mo. 4+ The characteristic peaks of 161.8 and 163.0 eV in S correspond to S 2- This is the typical valence state of MoS2.

[0035] In summary, this invention provides a method for preparing a cobalt polyacid-embedded carbon nanotube precursor: cobalt polyacid, carbon nanotubes, and deionized water are used as raw materials to form cobalt polyacid-embedded carbon nanotubes via a liquid-phase method. This precursor contains only cobalt and molybdenum as metallic elements, providing a good precursor for cobalt-doped molybdenum disulfide.

[0036] The present invention also provides a carbon nanotube confined one-dimensional cobalt-doped disulfide, which is obtained by post-sulfurization treatment of the above-mentioned cobalt polyacid embedded carbon nanotube precursor in a tube furnace, providing raw material support for subsequent material performance research.

[0037] The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A carbon nanotube-confined one-dimensional cobalt-doped molybdenum disulfide precursor, characterized in that, The precursor synthesis method uses cobalt polyacid and carbon nanotubes as raw materials, and efficiently fills the cobalt polyacid into the carbon nanotubes through a liquid phase method.

2. The carbon nanotube-confined one-dimensional cobalt-doped molybdenum disulfide precursor according to claim 1, characterized in that, The cobalt polyacid is preferably an Anderson-type cobalt polyacid; Preferably, the Anderson-type cobalt polyacid has the chemical formula (NH4)3[CoMo6O24H6]·7H2O.

3. The method for preparing the fluorine-doped nickel hydroxyl oxide precursor according to claim 1 or 2, characterized in that: Cobalt polyacid and carbon nanotubes were mixed in water and sonicated to embed the cobalt polyacid into the carbon nanotubes via a liquid-phase method.

4. The preparation method according to claim 3, characterized in that, The carbon nanotubes need to be opened, and the opening temperature of the carbon nanotubes is 500-600℃, more preferably 550℃. Preferably, the annealing process takes 2 to 4 hours.

5. The preparation method according to claim 3, characterized in that, Excess cobalt polyacid is dissolved in water to form a supersaturated solution. Preferably, the solvent for the supersaturated solution is deionized water. Preferably, the ratio of cobalt polyacid to solvent is 20–50 mg / mL.

6. The preparation method according to claims 3 and 5, characterized in that, Open carbon nanotubes were mixed with a supersaturated solution of cobalt polyacid and stirred at room temperature. Preferably, the ratio of carbon nanotubes to a supersaturated cobalt polyacid solution is 3–5 mg / mL; Preferably, the stirring time is 3-4 days and the stirring speed is 800-1000 rpm; Preferably, the process further includes washing and filtering the stirred product to obtain the powder, which is the cobalt polyacid embedded carbon nanotube.

7. A method for preparing one-dimensional cobalt-doped molybdenum disulfide confined within carbon nanotubes, characterized in that, The product is obtained by high-purity sulfur and cobalt polyacid embedded carbon nanotube precursor obtained by the preparation method described in claim 3, and then subjected to high-temperature sulfurization in a tube furnace. Preferably, the calcination temperature is 120-800℃, and more preferably 350-550℃; Preferably, the calcination time is 2-3 hours.

8. The method for preparing one-dimensional cobalt-doped molybdenum disulfide confined within carbon nanotubes according to claim 7, characterized in that, The atmosphere conditions are argon and hydrogen; Preferably, the flow rate ratio of argon to hydrogen is 10-100:1-20, more preferably 50-80:10-20.

9. The method for preparing one-dimensional cobalt-doped molybdenum disulfide confined within carbon nanotubes according to claim 7, characterized in that, High-purity sulfur is located upstream of the tubular furnace, while cobalt polyacid is embedded with carbon nanotubes in the central heating zone of the tubular furnace.

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