A method for preparing a nanostructured tin-based sulfide material and applications thereof

Abstract

The application discloses a preparation method of nano-structured tin-based sulfide material and application thereof, and belongs to the technical field of nano-material preparation. The method is based on a normal-pressure chemical vapor deposition system, FTO conductive glass is used as a tin source and a growth substrate at the same time, and solid sulfur powder is used as a sulfur source. Through synergic regulation and control of the sulfur powder dosage and the growth temperature, the controllable growth of different phase nano-structures such as SnS2, Sn2S3 and SnS is realized. In the application, the FTO is used to supply the tin source in situ, so that the problems such as uneven tin source transportation, use of toxic precursors and the like in the traditional method are effectively solved, and the application has the advantages of simple process, safety and environmental protection, low cost, high product purity and strong controllability of phase, and the like. The application provides a material basis for the application of the tin-based sulfide in the fields of photoelectronic energy, energy catalysis and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of IV-VI compound nanomaterials, and particularly relates to a preparation method of a nanostructured tin-based sulfide material and application thereof. BACKGROUND

[0002] In recent years, two-dimensional layered materials such as graphene, transition metal chalcogenides, IV-VI compounds and the like have shown broad application prospects in the fields of nano-electronics, optoelectronics and energy catalysis due to their unique physical and chemical properties. Among them, tin-based sulfides (SnS2, Sn2S3, SnS) have shown significant potential in photovoltaic devices, energy storage systems, photocatalysis and photoelectric detection due to their adjustable band gap, high light absorption coefficient and typical layered structure. Specifically, SnS is a p-type semiconductor of orthorhombic system (band gap of about 1.2 eV), which has excellent electrical and thermoelectric properties and is often used in batteries and thermoelectric materials; SnS2 is an n-type semiconductor of hexagonal CdI2 type structure (indirect band gap of about 2.2 eV), which is suitable for photocatalysis and ultraviolet-visible light detectors due to its significant optical anisotropy and strong ultraviolet-visible light absorption. Sn2S3 is an n-type semiconductor containing mixed valence tin (Sn 2+ / Sn 4+ ), with a band gap of about 1.0-1.5 eV, and has good light absorption and charge transport performance, which is outstanding in solar cells and lithium / sodium ion batteries. Therefore, the high-quality and controllable synthesis of SnS2, Sn2S3, SnS and other phases is the key prerequisite for promoting the in-depth research and practical application of this type of material.

[0003] At present, the common preparation methods of tin-based sulfides (SnS2, Sn2S3, SnS) include chemical vapor deposition (CVD), solvothermal method, chemical bath deposition and the like, however, these methods still have a series of technical bottlenecks. In the process of solvothermal method, organic residues are easily introduced, subsequent washing is complicated, and oxidation of the material may occur in the drying stage; the thin films obtained by chemical bath deposition generally have the problems of many impurities and poor adhesion, and usually need subsequent treatment to improve the crystalline quality; the traditional chemical vapor deposition method often relies on highly toxic or strongly corrosive precursors (such as H2S, CS2, SnCl4), which not only requires strict sealing of the equipment and treatment of waste gas, but also significantly increases the process complexity and operating cost. In addition, the existing methods still face challenges in realizing the accurate regulation of different tin-based sulfide phases (SnS2, Sn2S3, SnS), and it is difficult to obtain the target pure phase material by simple and environmentally friendly process parameter adjustment in the same technical system, which seriously restricts the intrinsic property research and device application of the material.

[0004] Therefore, it is of great significance to develop a synthesis method without high-risk precursors, simple process and capable of realizing controlled growth of tin-based sulfide, so as to make the material system go to practical application. SUMMARY

[0005] In view of the technical problems of complex process, high cost and difficult phase control in the existing preparation technology of tin-based sulfide, the application provides a preparation method of nano-structured tin-based sulfide material and application thereof, wherein the tin-based sulfide includes at least one of SnS2, Sn2S3 and SnS. The method is based on chemical vapor deposition technology, adopts a new strategy of in-situ tin source supply based on FTO substrate, realizes safe, low-cost and controllable synthesis of SnS2, Sn2S3 and SnS nano-materials, and has the advantages of simple operation, low cost and strong controllability. Meanwhile, the obtained material has excellent stability in normal temperature and atmospheric environment, which lays a solid foundation for in-depth study of the properties of the material.

[0006] The technical scheme adopted by the application to achieve the above-mentioned purposes is as follows:

[0007] A preparation method of nano-structured tin-based sulfide material, wherein the tin-based sulfide includes one of SnS2, Sn2S3 and SnS, and the preparation method is based on a chemical vapor deposition system, uses FTO conductive glass as a tin source and a growth substrate, and uses solid sulfur powder as a sulfur source, and the preparation method comprises the following steps:

[0008] S1. Placing the FTO conductive glass in a constant temperature heating zone of the chemical vapor deposition system;

[0009] S2. Placing a source boat containing sulfur powder in an upstream of the constant temperature heating zone;

[0010] S3. Introducing a mixed gas of a protective gas and a reducing gas into the chemical vapor deposition system;

[0011] S4. Raising the constant temperature heating zone to 500-600 DEG C and performing a heat preservation reaction, so that the tin element released from the FTO conductive glass reacts with gaseous sulfur to in-situ grow the nano-structured tin-based sulfide material on the substrate;

[0012] By adjusting the amount of sulfur powder and the growth temperature of the constant temperature heating center region, the phase of the tin-based sulfide is selectively controlled, so that one of the target tin-based sulfides SnS2, Sn2S3 and SnS is obtained.

[0013] Further, the specific way of selective control is as follows:

[0014] When the amount of sulfur powder is 100-250 mg and the growth temperature is 500-550 DEG C, the target tin-based sulfide is SnS2;

[0015] When the amount of sulfur powder is 25 ~75 mg, and the growth temperature is 500~550℃, the target tin-based sulfide is Sn2S3;

[0016] When the amount of sulfur powder is 80~120 mg, and the growth temperature is 580~600℃, the target tin-based sulfide is SnS.

[0017] Further, in step S1, the sheet resistance of the FTO conductive glass is 7 ~ 14 ohms, and the thickness is 1.8-3.5 mm, preferably 2.0-2.5 mm; FTO is used as both the substrate and the tin source. This design can promote the full use of tin, avoiding the problems of low transport efficiency and uneven supply of tin source existing in the powder tin source.

[0018] Further, in step S1, the growth substrate is FTO, and the surface interface characteristics of the substrate are one of the decisive factors for the growth of tin-based sulfide SnS2, Sn2S3, and SnS nanostructures. The F ions doped in the SnO2 layer on the surface of FTO can effectively promote the growth of tin-based sulfide SnS2, Sn2S3, and SnS nanosheet materials.

[0019] Further, in step S2, the purity of the sulfur powder is not less than 99.9%, the distance between the source boat and the center of the constant temperature heating zone is 21.5 cm to 24.5 cm, and the source boat uses a high-temperature resistant container such as a quartz boat or a ceramic boat. In the chemical vapor deposition process, the loading amount of high-purity sulfur source directly affects the saturation vapor pressure of sulfur in the air, thereby regulating the growth kinetics of SnS2, Sn2S3, and SnS nano materials. By optimizing the distance between the source boat and the center of the constant temperature heating zone, the precursor vapor can be directionally transported under the driving of the mixed carrier gas, and the uncontrollable nucleation caused by premature thermal decomposition can be effectively prevented. Experimental data show that the axial spacing of 21.5~24.5 cm can precisely control the sulfur vapor partial pressure in the best process range, achieving a synergistic balance of surface diffusion and chemical adsorption kinetics.

[0020] Further, before the mixed gas is introduced in step S3, an inert protective gas (preferably argon) is introduced into the chemical vapor deposition system to purge the reaction chamber. The purging time is 30~60 minutes, and the gas flow rate is 200~500 sccm. sccm stands for Standard Cubic Centimeter per Minute, which means: the volume of gas flowing through a certain cross section per minute under standard temperature and pressure conditions (0℃, 1 atm) (in cubic centimeters or milliliters).

[0021] Further, in step S4, the mixed gas is composed of argon and hydrogen, the hydrogen flow rate is 1-10 sccm, the argon flow rate is 60-150 sccm, and the appropriate argon flow rate can effectively control the precursor vapor concentration gradient, so that the uniform growth of tin sulfide SnS2, Sn2S3 and SnS is realized, and the appropriate hydrogen flow rate can effectively reduce the activation energy required for the reaction, which is more conducive to the growth of tin sulfide SnS2, Sn2S3 and SnS.

[0022] Further, in step S4, the temperature rising time from room temperature to the growth temperature is 20-30 minutes, preferably 25-30 minutes, and the holding time at the growth temperature is 8-15 minutes, preferably 10-12 minutes.

[0023] Further, after the reaction in step S4 is completed, the chemical vapor deposition system is also naturally cooled, and the natural cooling is carried out in a mixed gas atmosphere.

[0024] The tin sulfide material prepared by the above preparation method is a nanostructure, which is directly grown on an FTO conductive glass substrate, and the phase is one of SnS2, Sn2S3 or SnS, wherein SnS2 has a sheet-like morphology, and Sn2S3 and SnS have a granular morphology.

[0025] The tin sulfide material prepared by the above preparation method is applied to prepare photoelectric devices, catalytic devices or energy storage devices.

[0026] Compared with the prior art, the beneficial effects of the technical solution are as follows:

[0027] (1) The FTO conductive glass is used as a solid tin source in the present application, and the Sn source is directly supplied by in-situ reaction, which overcomes the problems of low transport efficiency and uneven distribution of traditional powder tin source. This strategy optimizes the nucleation environment of the reaction interface, makes the growth process of SnS2, Sn2S3 and SnS nano-materials more efficient and controllable, and simplifies the process flow and reduces the production cost.

[0028] (2) The present application is based on atmospheric pressure chemical vapor deposition technology, and uses solid sulfur powder as a sulfur source, which avoids the use of strong toxic and corrosive precursors such as H2S and SnCl4 in traditional CVD process, significantly improves the operation safety, reduces the special requirements for equipment and environment, and provides the possibility for large-scale application.

[0029] (3) The present application can realize directional synthesis of SnS2, Sn2S3 and SnS three different phase nano materials in the same technical system by precisely regulating the key parameters such as sulfur powder dosage and growth temperature. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a digital photo of SnS2 nanosheet in Example 1;

[0031] Figure 2 is optical microscope characterization result of SnS2 nanosheet in Example 1;

[0032] Figure 3 is Raman spectrum characterization result of SnS2 nanosheet in Example 1;

[0033] Figure 4 is scanning electron microscope characterization result of SnS2 nanosheet in Example 1;

[0034] Figure 5 is X-ray diffraction characterization result of SnS2 nanosheet in Example 1;

[0035] Figure 6 is X-ray photoelectron spectroscopy characterization result of SnS2 nanosheet in Example 1;

[0036] Figure 7 is a digital photo of Sn2S3 nano material in Example 2;

[0037] Figure 8 is optical microscope characterization result of Sn2S3 nano material in Example 2;

[0038] Figure 9 is Raman spectrum characterization result of Sn2S3 nano material in Example 2;

[0039] Figure 10 is scanning electron microscope characterization result of Sn2S3 nano material in Example 2;

[0040] Figure 11 is X-ray diffraction characterization result of Sn2S3 nano material in Example 2;

[0041] Figure 12 is X-ray photoelectron spectroscopy characterization result of Sn2S3 nano material in Example 2;

[0042] Figure 13 is a digital photo of SnS nano material in Example 3;

[0043] Figure 14 The optical microscope characterization results of the SnS nanomaterial in Example 3 are shown in FIG. 1.

[0044] Figure 15 The Raman spectrum characterization results of the SnS nanomaterial in Example 3 are shown in FIG. 2.

[0045] Figure 16 The scanning electron microscope characterization results of the SnS nanomaterial in Example 3 are shown in FIG. 3.

[0046] Figure 17 The X-ray diffraction characterization results of the SnS nanomaterial in Example 3 are shown in FIG. 4.

[0047] Figure 18 The X-ray photoelectron spectroscopy characterization results of the SnS nanomaterial in Example 3 are shown in FIG. 5.

[0048] Figure 19 The optical microscope characterization results of the SnS2 nanomaterial (without hydrogen gas) in Comparative Example 1 are shown in FIG. 6.

[0049] Figure 20 The optical microscope characterization results of the SnS nanomaterial (the temperature of the heating center is 500°C) in Comparative Example 2 are shown in FIG. 7.

[0050] Figure 21 The Raman spectrum characterization results of the SnS nanomaterial (the temperature of the heating center is 500°C) in Comparative Example 2 are shown in FIG. 8. DETAILED DESCRIPTION

[0051] The technical solutions of the present application are described in detail below in combination with the drawings and specific examples, but it should be noted that the protection scope of the present application is not limited to the following examples.

[0052] Example 1

[0053] An FTO glass with a size of 1 cm x 0.5 cm was taken as a substrate, and the FTO substrate was placed on a graphite sheet, and then the graphite sheet loaded with the substrate was pushed into the center of the heating zone of a tube furnace. According to the direction of the gas flow from upstream to downstream, a quartz boat loaded with high-purity sulfur powder was placed at the upstream position of the tube furnace, and the mass of the sulfur powder was 250 mg, and the distance between the substrate and the heating center was 22.5 cm. First, 500 sccm of argon gas was introduced for 10 minutes to clean the reaction chamber to remove residual air in the chamber; then the hydrogen-argon mixed gas was switched in, wherein the flow rate of argon was 85 sccm and the flow rate of hydrogen was 5 sccm, and the gas environment in the tube furnace was stabilized by continuously introducing the gas into the reaction chamber. Subsequently, the temperature rising program was set: first, the temperature of the heating center was raised from room temperature to 500°C, and the temperature rising time was 20 minutes, and then the reaction was carried out at 500°C for 10 minutes. After the reaction system was naturally cooled to room temperature, the hydrogen and argon were turned off, and the FTO substrate was taken out to obtain SnS2 nanosheets, and a digital photo thereof is shown in FIG. 1.Figure 1 As shown.

[0054] The SnS2 nanosheets obtained in Example 1 were characterized by optical microscopy, Raman spectroscopy, scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The results are as follows: Figures 2 to 6 As shown. Optical and scanning electron microscopy revealed that SnS2 was deposited on the substrate surface and grew perpendicularly to the substrate to form hexagonal nanosheets. Raman spectroscopy characterization results indicated that the sample... -1 With 310 cm -1 There are two distinct characteristic peaks, corresponding to the E values ​​of SnS2. g and A 1g Two vibrational modes were observed, consistent with previous reports. X-ray diffraction characterization showed that the diffraction peaks of SnS2 nanosheets at 14.9°, 28.0°, 31.9°, 41.7°, 49.8°, and 52.2° corresponded well to the (001), (100), (101), (102), (110), and (111) crystal planes of hexagonal SnS2 (PDF#23-0677). X-ray photoelectron spectroscopy characterization showed that in SnS2, Sn... 4+ Sn 3d 3 / 2 and 3D 5 / 2 The orbits are located at 494.3 eV and 485.9 eV, S 2- S 2p 3 / 2 and S 2p 1 / 2 The orbits are located at 161.1 eV and 162.3 eV, which is largely consistent with previous reports.

[0055] Example 2

[0056] By changing the mass of S powder in Example 1 to 75 mg, while keeping other preparation conditions unchanged, Sn2S3 nanomaterials can be obtained, as shown in the digital photograph. Figure 7 As shown.

[0057] The Sn₂S₃ nanomaterials obtained in Example 2 were characterized by optical microscopy, Raman spectroscopy, scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The results are as follows: Figures 8 to 12 As shown. Sn₂S₃ nanoparticles were observed deposited on the substrate surface using optical and scanning electron microscopy. Raman spectroscopy characterization results indicate that the sample... -1 69 cm -1 150 cm -1 232 cm -1 And 304 cm -1 The characteristic peak at that point corresponds to the A of Sn2S3. 1gVibration mode; 249 cm -1 The peak at 26.6°, 31.9°, 37.9° correspond to the (111), (211), (250) crystal planes of Sn2S3 (PDF #14-0619), respectively, further proving that Sn2S3 nanomaterials were successfully generated. 1g Vibration mode. X-ray diffraction characterization results show that the Sn2S3 diffraction peaks at 26.6°, 31.9°, 37.9° correspond well to the (111), (211), (250) crystal planes of Sn2S3 (PDF #14-0619), respectively, further proving that Sn2S3 nanomaterials were successfully generated. X-ray photoelectron spectroscopy characterization results show that in Sn2S3, Sn has two oxidation states (Sn 2+ and Sn 4+ ), the Sn 3d 4+ and 3d 3 / 2 orbitals of Sn 5 / 2 are located at 493.7 eV and 485.3 eV, the Sn 3d 2+ and 3d 3 / 2 orbitals of Sn 5 / 2 are located at 492.1 eV and 483.9 eV, and the S 2p 2- and S 2p 3 / 2 orbitals of S 1 / 2 are located at 159.4 eV and 160.6 eV, which is consistent with previous reports.

[0058] Example 3

[0059] Take 1 cm x 0.5 cm FTO glass as the substrate, place the FTO substrate on a graphite sheet, and then push the graphite sheet loaded with the substrate into the center of the hot zone of the tube furnace. According to the direction of the gas flow from upstream to downstream, place the quartz boat loaded with high-purity sulfur powder at the upstream tube opening of the tube furnace. The mass of the sulfur powder is 100 mg, and the distance between the substrate and the heating center is 22.5 cm. First, pass argon at a flow rate of 500 sccm into the reaction cavity for 10 minutes to remove residual air in the cavity; then switch to pass hydrogen-argon mixed gas, where the argon flow rate is 85 sccm and the hydrogen flow rate is 5 sccm, continuously pass into the reaction cavity to stabilize the gas environment in the tube furnace. Then set the temperature rising program: first raise the temperature of the heating center from room temperature to 600°C, the temperature rising time is 30 minutes, then keep at 600°C for 10 min for reaction. After the reaction system is naturally cooled to room temperature, the hydrogen and argon are turned off, and the FTO substrate is taken out to obtain SnS nanomaterials, the digital photo of which is shown in Figure 13 .

[0060] The SnS nanomaterials obtained in Example 3 were characterized by optical microscope, Raman spectroscopy, scanning electron microscope, X-ray diffraction, and X-ray photoelectron spectroscopy, as shown in Figures 14 to 18As shown. Uniformly grown SnS nanoparticles on FTO were observed using optical and scanning electron microscopy, forming a thin film. Raman spectroscopy characterization results indicate that the sample exhibits [a certain characteristic] at 95 cm⁻¹. -1 158 cm -1 187 cm -1 220 cm -1 These four positions show distinct characteristic peaks, corresponding to the A peaks of SnS, respectively. 1 g B 2 3g A 2 g and A 3 g Four vibration modes, at 283 cm -1 The characteristic peak at that location also corresponds to the B peak of SnS. 2g The vibrational modes are consistent with previous reports, confirming the successful generation of SnS nanomaterials. X-ray diffraction pattern characterization results show that the diffraction peaks of SnS at 31.8° and 66.5° correspond well to the (040) and (171) crystal planes of orthorhombic SnS, respectively (PDF#39-0354). X-ray photoelectron spectroscopy characterization results indicate that in SnS, Sn... 2+ Sn 3d 3 / 2 and 3D 5 / 2 The orbits are located at 493.8 eV and 485.3 eV, S 2- S 2p 3 / 2 and S 2p 1 / 2 The orbitals are located at 160.8 eV and 161.9 eV. In addition, Sn was also found in SnS. 4+ Sn 3d 3 / 2 and 3D 5 / 2 The orbitals, located at 494.9 eV and 486.7 eV respectively, can be attributed to SnO2 formed by oxidation of the SnS surface.

[0061] Comparative Example 1

[0062] The process conditions were kept exactly the same as in Example 1, except that hydrogen gas was not introduced.

[0063] Experimental results show that the SnS2 nanosheets generated on the substrate after the reaction are sparsely distributed, such as... Figure 19 As shown, the size of the nanosheets is much smaller than that of the SnS2 nanosheets in Example 1. This indicates that hydrogen lowers the activation energy of the reaction, promoting further reaction of sulfur vapor with SnO2 to form SnS2 nanosheets. Therefore, the introduction of hydrogen is crucial for the growth of SnS2 nanosheets.

[0064] Comparative Example 2

[0065] The process conditions were kept exactly the same as in Example 3, except that the growth temperature was increased from 600°C to 650°C.

[0066] Experimental results show that although SnS was generated on the substrate after the reaction, the SnS was not uniformly distributed across the entire substrate, and the grown SnS was a molten mass, such as... Figure 20 As shown. Figure 21 The Raman spectral characterization results shown indicate that the sample at 94 cm⁻¹ -1 154 cm -1 183 cm -1 222 cm -1 These four positions show distinct characteristic peaks, corresponding to the A peaks of SnS, respectively. 1 g B 2 3g A 2 g and A 3 g Four vibrational modes confirmed that the grown sample was SnS nanomaterial. This indicates that excessively high temperatures can disrupt the uniformity of the nanostructure. Therefore, a suitable growth temperature is crucial for obtaining high-quality nanomaterials.

Claims

1. A method for preparing a nanostructured tin-based sulfide material, wherein the tin-based sulfide includes one of SnS2, Sn2S3, and SnS, the preparation method being based on a chemical vapor deposition system, using FTO conductive glass as the tin source and growth substrate, and solid sulfur powder as the sulfur source, comprising the following steps: S1. Place the FTO conductive glass in the constant temperature heating zone of the chemical vapor deposition system; S2. Place the source boat containing sulfur powder upstream of the constant temperature heating zone; S3. Introduce a mixture of protective gas and reducing gas into the chemical vapor deposition system; S4. The constant temperature heating zone is heated to 500℃~600℃ and kept at that temperature to allow the tin element released from the FTO conductive glass to react with gaseous sulfur, thereby growing a nanostructured tin-based sulfide material in situ on the substrate. in, By adjusting the amount of sulfur powder and the growth temperature of the constant-temperature heating center region, selective control of the tin-based sulfide phase can be achieved, thereby obtaining one of the target tin-based sulfides SnS2, Sn2S3, and SnS. The specific methods for achieving selective control are as follows: When the amount of sulfur powder used is 100~250 mg and the growth temperature is 500~550℃, the target tin-based sulfide is SnS2. When the amount of sulfur powder used is 25~75 mg and the growth temperature is 500~550℃, the target tin-based sulfide is Sn2S3. When the amount of sulfur powder used is 80~120 mg and the growth temperature is 580~600℃, the target tin-based sulfide is SnS.

2. The method for preparing the nanostructured tin-based sulfide material according to claim 1, characterized in that, In step S1, the sheet resistance of the FTO conductive glass is 7 to 14 ohms and the thickness is 1.8 to 3.5 mm.

3. The method for preparing the nanostructured tin-based sulfide material according to claim 1, characterized in that, In step S2, the purity of the sulfur powder is not less than 99.9%, and the distance between the source boat and the center of the constant temperature heating zone is 21.5 cm to 24.5 cm.

4. The method for preparing the nanostructured tin-based sulfide material according to claim 1, characterized in that, Before introducing the mixed gas in step S3, an inert protective gas is introduced into the chemical vapor deposition system to purge the reaction chamber for 30 to 60 minutes at a flow rate of 200 to 500 sccm.

5. The method for preparing the nanostructured tin-based sulfide material according to claim 1, characterized in that, In step S4, the mixed gas consists of argon and hydrogen, with a hydrogen flow rate of 1 to 10 sccm and an argon flow rate of 60 to 150 sccm.

6. The method for preparing the nanostructured tin-based sulfide material according to claim 1, characterized in that, In step S4, the heating time from room temperature to growth temperature is 20-30 minutes, and the holding time at the growth temperature is 8-15 minutes.

7. The method for preparing the nanostructured tin-based sulfide material according to claim 1, characterized in that, After the reaction in step S4 is completed, the chemical vapor deposition system is naturally cooled, which is carried out in a mixed atmosphere.

8. The tin-based sulfide material obtained by the preparation method according to any one of claims 1 to 7, characterized in that, The tin-based sulfide material is a nanostructure, which is directly grown on an FTO conductive glass substrate. Its phase is one of SnS2, Sn2S3 or SnS, wherein SnS2 has a plate-like morphology and Sn2S3 and SnS have a granular morphology.

9. The application of the tin-based sulfide material as described in claim 8 in the preparation of optoelectronic devices, catalytic devices or energy storage devices.

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