Preparation method of ni-doped flaky znO / mXene nano composite acetone gas sensitive sensing material

Abstract

The application relates to a preparation method of a Ni-doped flaky ZnO / MXene nanocomposite acetone gas-sensitive sensing material, which comprises the following steps: (1) dissolving zinc acetate dihydrate, nickel dichloride hexahydrate and polyvinylpyrrolidone in water, dropwise adding MXene solution while stirring, and then dropwise adding an alkali solution to obtain a reaction precursor solution; (2) transferring the reaction precursor solution into a reaction kettle to perform a hydrothermal reaction, drying and calcining a reaction product obtained in the step (2), and obtaining a Ni-doped flaky ZnO / MXene nanocomposite material. Compared with the prior art, the application has the advantages of simple process, low synthesis temperature and the like, and has good sensitive performance on acetone gas.

Description

Technical Field

[0001] This invention belongs to the field of nanocomposite gas sensor materials, and relates to a method for preparing a Ni-doped sheet-like ZnO / MXene nanocomposite acetone gas sensor material. Background Technology

[0002] Acetone (C3H6O) is colorless and transparent with a pungent odor. It is flammable and soluble in water and other organic solvents. As the simplest saturated ketone, it can dissolve many sparingly soluble substances and is a common chemical solvent and raw material in industry with many uses. Due to its low price and chemical reactivity, it has a wide range of applications in many fields such as physics, chemistry, coatings, adhesives, extractants, and pharmaceuticals.

[0003] However, acetone is volatile, flammable, and prone to explosion when exposed to open flames, and it also possesses a certain degree of toxicity. When the concentration of acetone is less than 500 ppm, the toxicity of inhaled acetone is relatively low; in the range of 500-1000 ppm, people may experience discomfort in the nose and throat; when the concentration reaches above 1000 ppm, headaches and dizziness will appear; and when the concentration further reaches 2000-10000 ppm, drowsiness, nausea, vomiting, paralysis, and even death may occur. Long-term exposure to an acetone atmosphere can also cause trauma or even permanent damage to the eyes, nose, and central nervous system. Therefore, the detection of acetone is of great importance for both industrial safety and the protection of public health.

[0004] Currently, semiconductor oxides are the most commonly used materials for making gas-sensitive elements. Single oxides with high sensitivity to acetone, such as SnO2, In2O3, NiO, WO3, ZnO, Co3O4 and Fe2O3, have excellent performance in detecting acetone gas. However, they still have problems such as low detection sensitivity, poor selectivity and stability, which cannot meet the requirements of practical applications. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a Ni-doped sheet-like ZnO / MXene nanocomposite acetone gas sensor, so as to solve the shortcomings of existing acetone gas sensors, such as low sensitivity, poor selectivity and poor stability.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A method for preparing a Ni-doped sheet-like ZnO / MXene nanocomposite acetone gas-sensitive material includes the following steps:

[0008] (1) Dissolve zinc acetate dihydrate, nickel dichloride hexahydrate and polyvinylpyrrolidone in water, add MXene solution dropwise while stirring, and then add alkaline solution to obtain the reaction precursor solution;

[0009] (2) The precursor solution was transferred to a reaction vessel for hydrothermal reaction. The resulting reaction product was dried and calcined to obtain Ni-doped sheet-like ZnO / MXene nanocomposite material.

[0010] Furthermore, in step (1), the molar ratio of zinc acetate dihydrate to nickel dichloride hexahydrate is 1:0.01-0.2.

[0011] Furthermore, in step (1), the mass of polyvinylpyrrolidone added is 2-6 times the mass of zinc acetate dihydrate.

[0012] Furthermore, in step (1), the amount of MXene solution added satisfies the following condition: the amount of MXene is 0.1%-0.5% of the mass of zinc acetate dihydrate.

[0013] Furthermore, in step (1), the MXene in the MXene solution is Ti3C2.

[0014] Furthermore, in step (1), the alkaline solution is a urea solution, and the amount added satisfies the following condition: the amount of urea is 5-25 times the amount of zinc acetate dihydrate.

[0015] Furthermore, in step (2), the hydrothermal reaction temperature is 100-120℃ and the time is 5-8h.

[0016] Furthermore, in step (2), the calcination temperature is 400℃ and the time is 1-3 hours.

[0017] Adding urea solution to zinc acetate dihydrate and nickel dichloride hexahydrate will produce a precipitate. Initially, a large number of amorphous particles or small crystals will form, i.e., hydroxides of each metal. When the hydroxides are heated by a hydrothermal reaction, the mixture of metal hydroxides will react at a higher temperature to form doped metal oxides. The hydrothermal reaction temperature affects the purity and product morphology of the gas-sensitive material. At a suitable hydrothermal reaction temperature, the gas-sensitive material has a smaller and more uniform particle size. At a lower hydrothermal reaction temperature, it is difficult to obtain a pure product with an irregular morphology; at a higher hydrothermal reaction temperature, the particle size of the material increases, which is not conducive to gas adsorption. The reaction time also affects the product morphology of the gas-sensitive material. If the reaction time is too low, the product is impure and incompletely developed; if the reaction time is too high, the product particle size increases, which is detrimental to the adsorption performance of the material. An appropriate amount of dispersant is beneficial to promoting the dispersion of reactants in water. Too little dispersant is not conducive to the dispersion of reactants by the dispersant, but too much dispersant will hinder the reaction between reactants, and the product is not easy to wash away the dispersant.

[0018] Existing acetone sensors suffer from drawbacks such as low monitoring sensitivity, poor selectivity, and poor stability. This invention provides a method for preparing a Ni-doped sheet-like ZnO / MXene nanocomposite acetone gas sensor, which has the advantages of simple process, low synthesis temperature, and good sensitivity to acetone gas. Detailed Implementation

[0019] The present invention will now be described in detail with reference to specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0020] In the following embodiments, unless otherwise specified, the raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art.

[0021] Example 1

[0022] Zinc acetate dihydrate and nickel dichloride hexahydrate were weighed according to a molar ratio of 1:0.01, wherein 0.4390 g of zinc acetate dihydrate and 0.0048 g of nickel dichloride hexahydrate were weighed. 1.0000g of polyvinylpyrrolidone was weighed and dissolved in 30ml of deionized water. MXene (Ti3C2) solution was added dropwise while stirring, with the amount being 0.1% (mass ratio) of the amount of zinc acetate. A certain amount of urea was weighed, with the amount being 5 times the amount of zinc acetate dihydrate. It was added to 10ml of deionized water and fully dissolved, then slowly added dropwise to the solution containing the raw materials. The mixture was stirred at room temperature on a magnetic stirrer. The solution was then transferred to a stainless steel reactor for hydrothermal reaction at 120℃ for 8 hours to obtain a nanocomposite material, which was then dried in an oven. The dried solid product was calcined at 400℃ for 1 hour to obtain a nanocomposite gas-sensitive material with a response value of 17.8 and an optimal operating temperature of 320℃.

[0023] Comparative Example 1

[0024] The results are largely the same as in Example 1, except that the hydrothermal temperature is 80℃ and the time is 5 hours, resulting in a nanocomposite gas-sensitive material with a response value of 14.0 and an optimal operating temperature of 320℃.

[0025] Comparative Example 2

[0026] The results are largely the same as in Example 1, except that the hydrothermal temperature is 140℃ and the time is 5 hours, resulting in a nanocomposite gas-sensitive material with a response value of 15.6 and an optimal operating temperature of 320℃.

[0027] Example 2

[0028] Zinc acetate dihydrate and nickel dichloride hexahydrate were weighed according to a molar ratio of 1:0.05, with 0.4390 g of zinc acetate dihydrate and 0.0238 g of nickel dichloride hexahydrate. 2.0000 g of polyvinylpyrrolidone was also added. These were dissolved in 30 ml of deionized water. While stirring, MXene (Ti3C2) solution was added dropwise at a rate of 0.1% (mass ratio) of the amount of zinc acetate dihydrate. A certain amount of urea, five times the amount of zinc acetate, was weighed and dissolved in 10 ml of deionized water. This urea was then slowly added dropwise to the solution containing the raw materials and mixed. The solution was stirred at room temperature using a magnetic stirrer. The mixture was then transferred to a stainless steel reactor for hydrothermal reaction at 100°C for 8 hours to obtain a nanocomposite material, which was then dried in an oven. The dried solid product was calcined at 400°C for 2 hours to obtain a nanocomposite gas-sensitive material with a response value of 22.1 and an optimal operating temperature of 320°C.

[0029] Comparative Example 3

[0030] Compared with Example 2, most of the results are the same, except that the hydrothermal temperature is 100℃ and the time is 5 hours, resulting in a nanocomposite gas-sensitive material with a response value of 18.5 and an optimal operating temperature of 320℃.

[0031] Comparative Example 4

[0032] Compared with Example 2, most of the results are the same, except that the hydrothermal temperature is 140℃ and the time is 10 hours, resulting in a nanocomposite gas-sensitive material with a response value of 21.4 and an optimal operating temperature of 320℃.

[0033] Example 3

[0034] Zinc acetate dihydrate and nickel dichloride hexahydrate were weighed according to a molar ratio of 1:0.1, with 0.4390 g of zinc acetate and 0.0476 g of nickel dichloride hexahydrate. 3.0000 g of polyvinylpyrrolidone was dissolved in 30 ml of deionized water, and MXene (Ti3C2) solution was added dropwise while stirring, at a mass ratio of 0.1% of the amount of zinc acetate dihydrate. A certain amount of urea was weighed, five times the amount of zinc acetate, and dissolved completely in 10 ml of deionized water. This urea was then slowly added dropwise to the solution containing the raw materials and mixed. The solution was stirred at a constant temperature using a magnetic stirrer. The mixture was then transferred to a stainless steel reactor for hydrothermal reaction at 120°C for 6 hours to obtain nanomaterials, which were then dried in an oven. The dried solid product was calcined at 400°C for 1 hour to obtain a nanocomposite gas-sensitive material with a response value of 15.5 and an optimal operating temperature of 320°C.

[0035] Comparative Example 5

[0036] Compared with Example 3, most of the results are the same, except that 4.0000g of polyvinylpyrrolidone was used to obtain a nanocomposite gas-sensitive material with a response value of 14.6 and an optimal operating temperature of 320℃.

[0037] Comparative Example 6

[0038] Compared with Example 3, most of the results are the same, except that 5.0000g of polyvinylpyrrolidone was used to obtain a nanocomposite gas-sensitive material with a response value of 13.5 and an optimal operating temperature of 320℃.

[0039] Example 4:

[0040] Compared with Example 1, most of the results are the same, except that the amount of nickel dichloride is adjusted so that the molar ratio of zinc acetate dihydrate to nickel dichloride is 1:0.2, resulting in a nanocomposite gas-sensitive material with a response value of 14.8 and an optimal operating temperature of 320°C.

[0041] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for preparing a Ni-doped sheet-like ZnO / MXene nanocomposite acetone gas-sensitive material, characterized in that, Includes the following steps: (1) Dissolve zinc acetate dihydrate, nickel dichloride hexahydrate and polyvinylpyrrolidone in water, add MXene solution dropwise while stirring, and then add alkaline solution to obtain the reaction precursor solution; (2) The precursor solution was transferred to the reactor for hydrothermal reaction, and the resulting reaction product was dried and calcined to obtain Ni-doped sheet-like ZnO / MXene nanocomposite material. In step (1), the molar ratio of zinc acetate dihydrate to nickel dichloride hexahydrate is 1:0.01-0.2; In step (1), the mass of polyvinylpyrrolidone added is 2-6 times the mass of zinc acetate dihydrate; In step (1), the amount of MXene solution added satisfies the following condition: the amount of MXene is 0.1%-0.5% of the mass of zinc acetate dihydrate; In step (1), the MXene in the MXene solution is Ti3C2; In step (1), the alkaline solution is a urea solution; The amount of urea solution added should meet the following requirement: the amount of urea should be 5-25 times the amount of zinc acetate dihydrate. In step (2), the temperature of the hydrothermal reaction is 100-120℃; In step (2), the calcination temperature is 400℃ and the time is 1-3 hours.

2. The method for preparing a Ni-doped sheet-like ZnO / MXene nanocomposite acetone gas-sensitive material according to claim 1, characterized in that, In step (2), the hydrothermal reaction takes 5-8 hours.