Method for synthesizing SnS and SnS2 through urea-regulated hydrothermal method

Abstract

The invention discloses a method for synthesizing SnS and SnS2 through a urea regulation and control hydrothermal method, and belongs to the technical field of preparation of SnSx. According to the invention, the product type can be regulated and controlled only through the presence or absence of urea, and the process flow is simplified; a hydrothermal method is adopted, the reaction temperature is low, equipment is simple, and energy consumption is low; the urea is non-toxic and cheap, so that the problems of potential safety hazards and environmental pollution caused by using toxic reagents in the traditional method are avoided; the product generated by the hydrothermal method is high in purity and uniform in morphology, can be further purified through centrifugation and washing steps, and is suitable for large-scale production; in conclusion, by introducing the urea, the hydrothermal reaction environment is ingeniously regulated and controlled, selective synthesis of SnS and SnS2 is realized, and the method has the advantages that the technological process is simplified, the cost is reduced, the safety is improved, meanwhile, the high quality of the product is ensured, and the method has wide application prospects in the fields of photoelectric devices, battery materials and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of SnS x , and particularly relates to a method for synthesizing SnS and SnS2 by hydrothermal method through urea regulation. BACKGROUND

[0002] As an important material preparation method, the hydrothermal method is widely used in the field of material science. It is a method in which a special sealed reaction container (high-pressure reaction kettle) is used, an aqueous solution is used as a reaction medium, the reaction container is heated to create a high-temperature and high-pressure reaction environment, and substances that are usually difficult to dissolve or insoluble are dissolved and recrystallized. This method has many advantages, such as complete grain development of the prepared powder, small and uniform particle size, light particle agglomeration, use of relatively cheap raw materials, easy to obtain appropriate stoichiometric substances and crystal form. At present, the hydrothermal method is developing towards low temperature and low pressure, and special hydrothermal methods adding other force fields (such as direct current field, magnetic field and microwave field) have also appeared, further expanding its application range and the diversity of prepared materials.

[0003] Although the traditional method for preparing SnS, such as template-assisted electrochemical deposition technology, can prepare highly oriented SnS nanowire arrays with uniform diameter distribution and achieve structure regulation, the process has high requirements for equipment and process, relatively high preparation cost, and limited production, which is difficult to meet the needs of large-scale industrial production; although the SnS nanowires prepared by catalyst-induced chemical vapor deposition technology have good light absorption characteristics and can be used for solar cell assembly, the reaction conditions of this technology are harsh, the requirements for reaction equipment are high, and impurities may be introduced during the preparation process to affect the purity of the product; although low-temperature gas phase synthesis can control the stoichiometric ratio and uniform coverage at the molecular level, it also has problems such as complex equipment, high cost and low production efficiency.

[0004] Although the hydrazine solution method can synthesize large-scale high-quality SnS2 ultra-thin layered materials, hydrazine is toxic, which poses a safety hazard in the production process and has certain harm to the environment, and the post-processing process is complex; although the oxide sulfuration method and the thermal evaporation method can prepare single-layer or few-layer SnS2 on a large scale, the reaction process has high energy consumption, high requirements for the high-temperature resistance of the equipment, and it is difficult to accurately control the morphology and size uniformity of the product during the preparation process; although the hydrothermal / solvothermal method can prepare doped or heterojunction structured SnS2 nanosheets for gas sensing applications, the reaction time is relatively long, the yield is difficult to improve, and the cost control is difficult in large-scale production; when preparing SnS2 nano / micro powder by ultrasonic chemical method, the power and frequency of the ultrasonic equipment are strictly required, and the consistency of the products prepared in different batches is difficult to guarantee.

[0005] Urea, as a common, cheap and environmentally friendly reagent, can participate in the hydrothermal reaction system, which can change the kinetics and thermodynamics of the reaction, so as to realize the efficient synthesis of SnS and SnS2 under relatively mild conditions. The method has the advantages of mild reaction conditions, low cost, simple operation, high product purity, large-scale preparation, etc., which can effectively solve the problems existing in the prior art, and has good application prospect in the fields of optoelectronic devices, battery electrode materials, sensors and the like, and promotes the technology upgrading and development of related industries. SUMMARY

[0006] The present application aims to overcome the defects of the prior art and provides a method for synthesizing SnS and SnS2 by urea regulation hydrothermal method.

[0007] The object of the present application can be achieved by the following technical solutions: A method for synthesizing SnS by urea regulation hydrothermal method, comprising the following steps: Step A1, dissolve urea and anhydrous tin dichloride in deionized water, then add thioacetamide into the above mixture, put it on a magnetic stirrer and stir magnetically to obtain a mixed solution; Step A2, pour the obtained mixed solution into a reaction kettle, seal the reaction kettle and put it into a muffle furnace for reaction, after the reaction is completed, centrifuge the obtained solution, and then wash it with deionized water and anhydrous ethanol alternately for 2-3 times, and finally dry it in an oven to obtain black SnS.

[0008] As a further technical solution, the molar ratio of urea, anhydrous tin dichloride and thioacetamide in step A1 is 1:0.6:1.

[0009] As a further technical solution, the time of magnetic stirring in step A1 is 30-60 min.

[0010] As a further technical solution, the temperature of muffle furnace reaction in step A2 is 170-180℃, and the reaction time is 8-10h.

[0011] As a further technical solution, the temperature of oven drying in step A2 is 70-80℃, and the drying time is 8-10h.

[0012] The present application also provides a method for synthesizing SnS2 by urea regulation hydrothermal method, comprising the following steps: B1, dissolve anhydrous tin dichloride in deionized water, then add thioacetamide into the above mixture, put it on a magnetic stirrer and stir magnetically to obtain a mixed solution; B2, pour the obtained mixed solution into a reaction kettle, seal the reaction kettle and put it into a muffle furnace to react, centrifuge the obtained solution after the reaction, and wash it with deionized water and anhydrous ethanol alternately for 2-3 times, and finally dry it in an oven to obtain a light yellow SnS2 powder.

[0013] As a further technical solution, the molar ratio of anhydrous tin dichloride to thioacetamide in step B1 is 0.6:1.

[0014] As a further technical solution, the time of magnetic stirring in step B1 is 30-60 min.

[0015] As a further technical solution, the temperature of muffle furnace reaction in step B2 is 170-180℃, and the reaction time is 8-10h.

[0016] As a further technical solution, the temperature of oven drying in step B2 is 70-80℃, and the drying time is 8-10h.

[0017] The present application uses a hydrothermal method, which promotes the dissolution and recrystallization of reactants under high temperature and high pressure, generates products with complete crystal grains and uniform size, and enables the synthesis of SnS and SnS2 to be completed efficiently under mild conditions; the synthesis of SnS and SnS2 is accurately controlled by adding or not adding urea, urea decomposes to generate ammonia and carbon dioxide in the hydrothermal reaction, the release of ammonia increases the pH value of the reaction system, forming an alkaline environment, thereby affecting the reaction path of tin dichloride and thioacetamide, Sn 2+ tends to combine with S 2- to form SnS; while in the absence of urea, Sn 2+ is more easily oxidized to Sn 4+ , which combines with S 2- to form SnS2 Advantages of the present application: 1. The prior art usually needs different reaction conditions or additives to synthesize SnS and SnS2 respectively, while the present application can control the product type (SnS or SnS2) by the presence or absence of urea, simplifying the process flow; 2. Traditional methods such as chemical vapor deposition, template-assisted electrochemical deposition, etc. require high temperature, high pressure or complex equipment, while the present application uses a hydrothermal method, which has a lower reaction temperature, simple equipment and low energy consumption; 3. Urea is non-toxic and inexpensive, avoiding the safety hazards and environmental pollution problems of using toxic reagents (such as hydrazine) in traditional methods; 4. The product generated by the hydrothermal method has high purity and uniform morphology, and can be further purified through centrifugation and washing steps, suitable for large-scale production; In summary, the present application realizes the selective synthesis of SnS and SnS2 by introducing urea to skillfully control the hydrothermal reaction environment, and has the advantages of simplifying the process, reducing the cost, improving the safety, ensuring the high quality of the product, and having a wide application prospect in the fields of photoelectric devices, battery materials and the like. BRIEF DESCRIPTION OF DRAWINGS

[0018] The present application will be further described below with reference to the drawings.

[0019] Figure 1 X-ray powder diffraction (XRD) pattern of SnS prepared in Example 1 of the present application.

[0020] Figure 2 X-ray powder diffraction (XRD) pattern of SnS2 prepared in Example 2 of the present application. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0022] Example 1 A method for synthesizing SnS by urea control hydrothermal method, comprising the following steps: Step A1, 10 mmol of urea and 0.6 mmol of anhydrous tin dichloride are dissolved in 30 mL of deionized water, then 10 mmol of thioacetamide is added to the above mixture, and the mixture is placed on a magnetic stirrer for magnetic stirring for 30 min to obtain a mixed solution; Step A2, the obtained mixed solution is poured into a reaction kettle, the reaction kettle is sealed and placed in a muffle furnace, and reaction is carried out at 170℃ for 10 h. After the reaction is completed, the obtained solution is centrifuged, and then washed with deionized water and anhydrous ethanol alternately for 2 times. Finally, it is placed in a 70℃ oven and dried for 10 h to obtain black SnS. The diffraction pattern is obtained by using an X-ray diffractometer, as shown in Figure 1

[0023] Example 2 A method for synthesizing SnS by urea control hydrothermal method, comprising the following steps: Step A1, 10 mmol of urea and 0.6 mmol of anhydrous tin dichloride are dissolved in 30 mL of deionized water, then 10 mmol of thioacetamide is added to the above mixture, and the mixture is placed on a magnetic stirrer for magnetic stirring for 30 min to obtain a mixed solution; ​Step A2, the obtained mixed solution was poured into a reaction kettle, the reaction kettle was sealed and put into a muffle furnace to react at 170°C for 10h. After the reaction was completed, the obtained solution was centrifuged, washed with deionized water and anhydrous ethanol alternately for 2 times, and finally dried in a 70°C oven for 10h to obtain a light yellow SnS2 powder; an X-ray diffractometer was used to obtain a diffraction chart as shown in Figure 2 .

[0024] In the description of the specification, the description of the terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0025] The above is only an example and description of the present application, and those skilled in the art can make various modifications or supplements to the described specific embodiments or use similar ways to replace, as long as it does not deviate from the invention or exceed the scope defined by the present claims, which shall belong to the protection scope of the present application.

Claims

1. A method for controlling hydrothermal synthesis of SnS and SnS2 by urea, characterized in that, The method comprises the following steps: Step A, dissolve urea and anhydrous tin dichloride in deionized water, then add thioacetamide, put into a muffle furnace after magnetic stirring, carry out reaction, after the reaction is completed, wash, oven dry, get black SnS; Step B, dissolve anhydrous tin dichloride in deionized water, then add thioacetamide, put into a muffle furnace after magnetic stirring, carry out reaction, after the reaction is completed, wash, oven dry, get light yellow SnS2.

2. The method for controlling hydrothermal synthesis of SnS and SnS2 by urea according to claim 1, characterized in that, The molar ratio of urea, anhydrous tin dichloride and thioacetamide in step A is 1:0.6:

1.

3. The method for controlling hydrothermal synthesis of SnS and SnS2 by urea according to claim 1, characterized in that, The molar ratio of anhydrous tin dichloride and thioacetamide in step B is 0.6:

1.

4. The method for controlling hydrothermal synthesis of SnS and SnS2 by urea according to claim 1, characterized in that, The time of magnetic stirring in steps A and B is 30-60 min.

5. The method for controlling hydrothermal synthesis of SnS and SnS2 by urea according to claim 1, characterized in that, The temperature of muffle furnace reaction in steps A and B is 170-180℃, and the reaction time is 8-10h.

6. The method for controlling hydrothermal synthesis of SnS and SnS2 by urea according to claim 1, characterized in that, The temperature of oven drying in steps A and B is 70-80℃, and the drying time is 8-10h.

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