Nitrogen-sulfur double-doped WO3 hollow sphere, preparation method thereof and application of nitrogen-sulfur double-doped WO3 hollow sphere in photoelectric reaction

Abstract

The invention discloses a nitrogen-sulfur double-doped WO3 hollow sphere, a preparation method thereof and application of the nitrogen-sulfur double-doped WO3 hollow sphere in photoelectric reaction, the chemical formula of the nitrogen-sulfur double-doped WO3 hollow sphere is NS-WO3, and the specific capacity of the nitrogen-sulfur double-doped WO3 hollow sphere is larger than or equal to 400 F / g; the forbidden bandwidth of the nitrogen-sulfur double-doped WO3 hollow sphere is 2.60 eV or below, and the recombination rate of photo-induced electrons is obviously reduced; the preparation method comprises the following steps: (1) ultrasonically dissolving a tungsten source in deionized water, then adding an alcohol solvent and thiourea, adjusting the pH value of a reaction solution to be acidic while stirring, and obtaining a white suspension after the reaction solution is stable; (2) pouring the white suspension into a polytetrafluoroethylene stainless steel reaction kettle, sealing the reaction kettle, then putting the reaction kettle into a forced air drying oven, controlling the reaction temperature to be 150-250 DEG C and the reaction time to be 15-30 hours, cooling the temperature to room temperature after the reaction is completed, then centrifuging, washing the precipitate with ethanol, drying, and then roasting in an inert atmosphere for 2-5 hours to obtain NS-WO3 hollow spheres; the prepared NS-WO3 has excellent performance in the reaction of visible light catalytic degradation of organic pollutants acridine orange and methylene blue.

Description

Technical Field

[0001] The present invention relates to the technical field of nano material preparation and application, in particular to a nitrogen-sulfur dual-doped WO 3 Hollow sphere, preparation method thereof and application thereof in photoelectric reaction. Background Art

[0002] Tungsten Oxide (WO 3 ) is an important acidic transition metal oxide, which can be used not only as a functional material in the fields of photoelectric color change, gas sensing and electrode energy storage, but also as an excellent heterogeneous catalyst in the fields of light, electricity and heat catalysis. WO 3 The performance of WO is greatly affected by its particle size and morphology. 3 The structural control of WO is an important branch in related research fields. The hollow sphere structure has aroused great interest due to its uniform size, low density, large specific surface area and wide application (Chem. Soc. Rev., 2011, 40, 5472−5491; Anal. Chem., 2022,94, 6967−6975). 3 There are three main methods for preparing hollow spheres: (1) Under hydrothermal conditions, sodium tungstate is used as the tungsten source and oxalic acid is used as the structure directing agent to prepare WO 3 Nanosheets, which then self-assemble to obtain WO 3 Hollow spheres (Appl. Surf. Sci., 2019, 463, 1078–1084; Electrochim. Acta, 2016, 210, 147–154); (2) Under solvothermal conditions, tungsten hexachloride was used as the tungsten source and acetic acid was used as the solvent to obtain WO 3 Hollow spheres with self-assembled particles (Mater. Lett., 2021, 302,130460); (3) Using carbon spheres as hard templates, tungsten hexachloride as tungsten source, DMF as solvent, adding trace amounts of water to hydrolyze the tungsten source, and removing the template after aging and air calcination to obtain WO 3 Hollow spheres (Inorg. Chem., 2004, 43, 5442−5449). However, the WO obtained by the first two methods 3 The hollow spheres are large in size and thick in wall; the introduction of carbon spheres makes the preparation steps complicated and increases the cost, so it is still necessary to explore simple and fast WO 3 Hollow sphere preparation method.

[0003] In addition, non-metallic nitrogen or sulfur doping can not only reduce the band gap of semiconductor oxide catalysts, but also enhance their conductivity, thereby enhancing the photocatalytic and electrochemical properties of oxide materials (J. Mater. Chem. A, 2018, 6, 2797–2807; Chem. Eng. J., 2021, 408, 127257; Electrochim. Acta, 2017, 248, 37−45). 3 The method of nitrogen doping of nanoparticles is to dissolve tungstic acid in hydrogen peroxide with stirring for a long time, add urea to dry it, grind it thoroughly, and finally roast it to obtain the product (Sol. Energy Mater. Sol. Cells, 2016,149, 294–303;Environ. Chem. Lett., doi:10.1007 / s10311-015-0538-y); sulfur doping is mainly the secondary hydrothermal and roasting introduction method of thiourea (Chem. Phys. Lett., 2016, 651, 183–187; Environ. Sci.Pollut. Res.,10.1007 / s11356-020-07827-z). It can be seen that the reported WO 3 The preparation process of nitrogen-doping and sulfur-doping methods is relatively complicated. Moreover, there is no literature report on the preparation of nitrogen-sulfur dual-doped WO. 3 (NS-WO 3 ) Hollow ball technology. Summary of the invention

[0004] The purpose of the present invention is to prepare WO 3 The hollow sphere and its nitrogen and sulfur doping technology are inadequate, and a nitrogen-sulfur dual-doped WO is provided. 3 Hollow sphere and preparation method thereof and application thereof in photoelectric reaction, nitrogen-sulfur dual-doped WO prepared by the present invention 3 The chemical formula of hollow sphere is NS-WO 3 , has excellent electrochemical performance, and its specific capacity is greater than 400 F / g; WO after nitrogen-sulfur co-doping 3 The band gap width of the hollow sphere is reduced from the commercial 2.72eV to below 2.60 eV, and the recombination rate of photogenerated electrons is significantly reduced.

[0005] A nitrogen-sulfur dual-doped WO of the present invention 3 Hollow sphere, its chemical formula is NS-WO 3 , has excellent electrochemical performance, and its specific capacity is greater than 400 F / g; WO after nitrogen-sulfur co-doping 3The band gap width of the hollow sphere is reduced from the commercial 2.72eV to below 2.60 eV, and the recombination rate of photogenerated electrons is significantly reduced.

[0006] A nitrogen-sulfur dual-doped WO of the present invention 3 The method for preparing hollow spheres comprises the following steps: (1) ultrasonically dissolve the tungsten source in deionized water, then add alcohol solvent and thiourea, and adjust the pH value of the reaction solution to the acidic range with 2-5 mol / L protonic acid under stirring, and obtain a white suspension after stabilization; (2) The white suspension obtained in step (1) is poured into a polytetrafluoroethylene stainless steel reactor, which is sealed and placed in a blast drying oven. The reaction temperature is controlled at 170°C to 220°C and the reaction time is 10h to 30h. After the reaction is completed, the temperature is lowered to room temperature and then the precipitate is washed with ethanol by centrifugation. After drying at 50°C to 100°C, the precipitate is calcined at 250°C to 450°C in an inert atmosphere for 2h to 5h to obtain nitrogen-sulfur dual-doped WO 3 Hollow ball.

[0007] Preferably, the tungsten source in step (1) of the present invention is a water-soluble tungstate, selected from any one of sodium tungstate, ammonium tungstate, ammonium metatungstate and ammonium paratungstate.

[0008] Preferably, the alcohol solvent in step (1) of the present invention is any one or more selected from ethanol, n-propanol, isopropanol, n-butanol, isobutanol, n-pentanol, n-hexanol, n-octanol, glycerol, benzyl alcohol, and ethylene glycol.

[0009] Preferably, the protonic acid in step (1) of the present invention is any one or more selected from hydrochloric acid, nitric acid, sulfuric acid and acetic acid.

[0010] Preferably, the molar ratio of tungsten source: thiourea: deionized water: alcohol solvent in step (1) of the present invention is 1:10-30:50-80:150-350, and the pH of the solution is adjusted to 1.5-2.5 by protonic acid.

[0011] Preferably, in step (2), the volume of the polytetrafluoroethylene stainless steel reactor ranges from 50 mL to 500 mL, the reaction temperature is 190° C. to 210° C., the reaction time is 18 h to 24 h, the precipitate is washed with ethanol 2-3 times, and the drying temperature is 60° C. to 90° C.

[0012] Preferably, the inert atmosphere in step (2) comprises one or both of nitrogen and argon, the calcination temperature is 300° C. to 400° C., the heating rate is 5 to 8° C. / min, and the calcination time is 2 h to 3 h.

[0013] Preferably, the nitrogen-sulfur dual-doped WO of the present invention 3 The method for preparing hollow spheres comprises the following steps: (1) 2-15 mmol sodium tungstate was ultrasonically dissolved in 2.5-17 mL deionized water, and then 30-210 mL ethanol solvent and 32-210 mmol thiourea were added. The pH value of the reaction solution was adjusted to the acidic range with 2-5 mol / L protonic acid under stirring, and a white suspension was obtained after stabilization; (2) The white suspension obtained in step (1) is poured into a 50 mL to 500 mL polytetrafluoroethylene stainless steel reactor, which is sealed and placed in a forced air drying oven. The reaction temperature is controlled at 190° C. to 210° C. and the reaction time is 18 h to 24 h. After the reaction is completed, the temperature is lowered to room temperature and then the precipitate is washed with ethanol by centrifugation. After drying at 60° C. to 90° C., the precipitate is calcined at 300° C. to 400° C. in an inert atmosphere for 2 h to 3 h to obtain nitrogen-sulfur dual-doped WO 3 Hollow ball.

[0014] A nitrogen-sulfur dual-doped WO of the present invention 3 Application of hollow spheres in photoelectric reactions.

[0015] A nitrogen-sulfur dual-doped WO of the present invention 3 Application of hollow spheres in photoelectric reactions: nitrogen-sulfur co-doped WO 3 The hollow spheres showed better performance than commercial WO in the visible light photocatalytic degradation of organic pollutants acridine orange and methylene blue. 3 The particles had better activity, which completed 98% degradation of 20 mg / L acridine orange and methylene blue within 25 min and 17.5 min, respectively.

[0016] It should be noted that the NS-WO prepared in the present invention 3 The hollow spheres were subjected to scanning electron microscopy, transmission electron microscopy, and N 2 The results showed that the nitrogen-sulfur dual-doped WO was successfully obtained. 3 Hollow spheres, the bandgap width of the doped hollow spheres is reduced from the commercial 2.72eV to below 2.60 eV, and the recombination rate of photogenerated electrons is significantly reduced. 3 The hollow spheres showed better performance than commercial WO in the visible light photocatalytic degradation of organic pollutants acridine orange and methylene blue. 3 The particles have better activity, and 98% of 20 mg / L acridine orange and methylene blue were degraded within 25 min and 17.5 min, respectively; in addition, nitrogen-sulfur co-doped WO3 hollow spheres have excellent electrochemical performance, and their specific capacity is greater than 400F / g.

[0017] Compared with the prior art, the present invention has the following advantages and significant improvements: (1) The significant advantage of the present invention is that no hard template is introduced. Thiourea is used as a nitrogen source and a sulfur source and also acts as a bubble template. NS-WO can be obtained by simple solvent thermal and post-calcination. 3 Hollow spheres, the method is simple and fast, the reaction is mild, and it can be appropriately scaled up for preparation.

[0018] (2) NS-WO prepared by the present invention 3 The hollow spheres have small particle size, thin wall, high porosity, uniform morphology and large specific surface area.

[0019] (3) NS-WO prepared by the present invention 3 The hollow spheres showed better performance than commercial WO in the visible light photocatalytic degradation of organic pollutants acridine orange and methylene blue. 3 The particles have better activity and excellent electrochemical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 NS-WO obtained in Example 1 3 Optical photograph of a hollow sphere; Figure 2 NS-WO prepared in Example 1 3 Scanning electron micrographs and transmission electron micrographs of hollow spheres, N 2 Adsorption / desorption curves and X-ray powder diffraction peaks; Figure 3 NS-WO obtained in Example 1 3 1s peaks of nitrogen and sulfur in the X-ray photoelectron spectrum of the hollow sphere; Figure 4 NS-WO obtained in Example 1 3 Hollow sphere and commercial WO 3 Comparison of the photodegradation performance of acridine orange and the capacitance of the particles; Figure 5 NS-WO obtained in Example 2 3 Scanning electron microscope images of hollow spheres, X-ray powder diffraction peaks, and 1s peaks of nitrogen and sulfur in X-ray photoelectron spectroscopy; Figure 6 NS-WO obtained in Examples 1 and 2 3 Hollow sphere and commercial WO 3 Comparison of photoluminescence spectra of particles; Figure 7 NS-WO obtained in Examples 1 and 2 3 Hollow sphere and commercial WO 3 Comparison of UV-visible absorption spectra of particles; Figure 8 NS-WO obtained in Example 2 3 Hollow sphere and commercial WO 3Photodegradation properties of the particles for methylene blue; Fig. 9 NS-WO obtained in Example 3 3 Scanning electron microscope images, X-ray powder diffraction peaks and capacitance performance of hollow spheres. DETAILED DESCRIPTION

[0021] In order to better explain the technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with specific embodiments. The following embodiments are merely exemplary of the technical solution of the present invention and do not limit the present invention in any form. The serial numbers of the following embodiments are only for description and do not represent the advantages and disadvantages of the embodiments.

[0022] Example 1 A nitrogen-sulfur dual-doped WO 3 The method for preparing hollow spheres comprises the following steps: (1) Add 4 mmol of sodium tungstate to 5 mL of deionized water, dissolve it by ultrasonication, add 80 mL of ethanol and 60 mmol of thiourea, adjust the pH of the reaction solution to 2.0 with 5 mol / L hydrochloric acid while stirring, and obtain a white suspension after stabilization; (2) The white suspension was transferred into a 150 ml polytetrafluoroethylene stainless steel reactor, sealed and placed in a forced air drying oven, and reacted at 190 °C for 24 h; (3) After the reaction temperature drops to room temperature, centrifuge the precipitate, wash it twice with ethanol, and dry it at 70°C; (4) Pour the dried white sample into an ark and place it in the center of a tube furnace. Set the calcination temperature to 300 °C, the time to 2.5 h, the heating rate to 5 °C / min, and start calcination after argon is introduced for 30 min. When calcination is completed, white powder NS-WO is obtained. 3 .

[0023] Figure 1 NS-WO prepared in this example 3 Optical photos of hollow spheres (a) and (b) show that the prepared NS-WO 3 The appearance is white powder.

[0024] The NS-WO prepared in this example 3 Scanning electron microscopy and transmission electron microscopy, N 2 Adsorption / desorption and X-ray powder diffractometer characterization gave Figure 2 (a), (b), (c), (d) images, from Figure 2 (a) and (b) show that the prepared NS-WO 3 The product is a hollow sphere structure with a porous surface, small particle size, thin wall, multiple pores and uniform morphology. Figure 2(c) The data can be used to calculate NS-WO 3 The specific surface area of ​​the product is 45m 2 / g, which is larger than the surface area of ​​general nanorods. Figure 2 (d) It can be seen that NS-WO 3 The crystal form of the hollow sphere is hexagonal phase, and the PDF card number is 33-1387.

[0025] The NS-WO prepared in this example 3 X-ray photoelectron spectroscopy was used to characterize the Figure 3 As shown, from Figure 3 (a) and (b) show that the NS-WO prepared in this embodiment 3 The 1s peaks of nitrogen and sulfur appear in the hollow spheres, indicating that nitrogen and sulfur are doped into WO simultaneously. 3 middle.

[0026] The NS-WO prepared in this embodiment 3 Hollow sphere and commercial WO 3 The photodegradation performance of acridine orange was measured for the particles, and their respective capacitances were characterized. The results are shown in Figure 4 As shown in (a), (b), (c), (d), (e), and (f), from Figure 4 (a) and (b) show that the NS-WO prepared in this embodiment 3 The hollow spheres completed the degradation of 98% of 20 mg / L acridine orange within 20 min, while the commercial WO 3 In the same amount of time, only 58% of the degradation was completed; Figure 4 (c), (d), (e), and (f) show that the NS-WO prepared in this example 3 When the charging rate is 1A / g, the charging time is 300s, the discharging time is 400s, and the specific capacity reaches 700F / g. Moreover, in the charging rate range of 1A / g~40A / g, its specific capacity is greater than 450F / g. 3 Even under the slow charging condition of 1A / g, its specific capacity is only 100F / g, indicating that its capacitance performance is poor.

[0027] Example 2 A nitrogen-sulfur dual-doped WO 3 The method for preparing hollow spheres comprises the following steps: (1) Add 3 mmol of ammonium tungstate to 3 mL of deionized water, dissolve it by ultrasonication, add 55 mL of n-butanol and 39 mmol of thiourea, and adjust the pH of the reaction solution to 1.5 with 5 mol / L nitric acid while stirring. After stabilization, a white suspension is obtained; (2) The white suspension was transferred into a 100 ml polytetrafluoroethylene stainless steel reactor, sealed and placed in a forced air drying oven, and reacted at 210 °C for 20 h; (3) After the reaction temperature drops to room temperature, centrifuge the precipitate, wash it twice with ethanol, and dry it at 80°C; (4) Pour the dried white sample into an ark and place it in the center of a tube furnace. Set the calcination temperature to 330 °C, the time to 2 h, the heating rate to 8 °C / min, and start calcination after nitrogen is introduced for 30 min. When calcination is completed, white powder NS-WO is obtained. 3 .

[0028] The NS-WO prepared in this example 3 Scanning electron microscopy, X-ray powder diffractometer and X-ray photoelectron spectroscopy were used to characterize the Figure 5 Figures (a), (b), (c), and (d) are from Figure 5 (a) It can be seen that the prepared NS-WO 3 The product is still a hollow sphere structure with small particle size and uniform morphology. Figure 5 (b) It can be seen that NS-WO 3 The hollow spherical crystal form is hexagonal. Figure 5 (c) and (d) show that nitrogen and sulfur are doped into WO at the same time. 3 middle.

[0029] Adopting commercial WO 3 Particles and NS-WO prepared in Examples 1 and 2 3 The hollow spheres were characterized by photoluminescence spectroscopy, and the results were as follows Figure 6 As shown. Figure 6 It can be seen that compared with the commercialized WO 3 Particles, WO doped with nitrogen and sulfur prepared in Example 1 and Example 2 3 The excitation light intensity at 420 nm and 460 nm was significantly weakened, indicating that the recombination of photogenerated electrons and holes was greatly reduced.

[0030] Adopting commercial WO 3 Particles and NS-WO prepared in Examples 1 and 2 3 The hollow spheres were characterized by UV-visible absorption spectroscopy. Figure 7 As shown. Figure 7 It can be seen that compared with commercial WO 3 Particles, NS-WO prepared in Example 1 and Example 2 3 hollow spheres, the UV-visible spectra of both are red-shifted. Through corresponding calculations, it can be seen that commercial WO 3The band gaps of the particles, Example 1 and Example 2 are 2.72 V, 2.57 eV and 2.60 eV respectively. 3 The reduction in the bandgap width of the hollow sphere indicates that the utilization rate of light is improved.

[0031] The NS-WO prepared in this embodiment 3 Hollow sphere and commercial WO 3 The particles were tested for their photodegradation performance of methylene blue. The results are as follows Figure 8 As shown, from Figure 8 It can be seen that the NS-WO prepared in this embodiment 3 The hollow spheres completed the degradation of 98% of 20 mg / L methylene blue within 17.5 min, while the commercial WO 3 The particles only completed 44% degradation within 70 min.

[0032] Example 3 A nitrogen-sulfur dual-doped WO 3 The method for preparing hollow spheres comprises the following steps: (1) Add 2 mmol of ammonium metatungstate to 2.5 mL of deionized water, add 30 mL of isopropanol and 32 mmol of thiourea after ultrasonic dissolution, and adjust the pH of the reaction solution to 1.5 with 5 mol / L sulfuric acid under stirring to obtain a white suspension after stabilization; (2) The white suspension was transferred into a 50 ml polytetrafluoroethylene stainless steel reactor, sealed and placed in a forced air drying oven, and reacted at 200 °C for 18 h; (3) After the reaction temperature drops to room temperature, centrifuge the precipitate, wash it three times with ethanol, and dry it at 60°C; (4) Pour the dried white sample into an ark and place it in the center of a tube furnace. Set the calcination temperature to 400 °C, the time to 2 h, the heating rate to 5 °C / min, and start calcination after nitrogen is introduced for 30 min. After calcination, a white powdery NS-WO3 is obtained.

[0033] The NS-WO prepared in this example 3 Scanning electron microscope, X-ray powder diffractometer characterization and electrochemical performance test were carried out to obtain Fig. 9 (a), (b), (c), (d) images, from Fig. 9 (a) and (b) show that the prepared NS-WO 3 The product is a hollow sphere structure with small particles and uniform size, and the crystal form is still hexagonal. Fig. 9 (c) and (d) show that NS-WO 3 The product has a specific capacity of more than 400 F / g within the charging rate range of 1A / g~40A / g.

[0034] Example 4 A nitrogen-sulfur dual-doped WO 3 The method for preparing hollow spheres comprises the following steps: (1) Add 15 mmol of sodium tungstate to 17 mL of deionized water, dissolve it by ultrasonication, add 280 mL of ethanol and 210 mmol of thiourea, adjust the pH of the reaction solution to 2.0 with 5 mol / L hydrochloric acid while stirring, and obtain a white suspension after stabilization; (2) The white suspension was transferred into a 500 mL polytetrafluoroethylene stainless steel reactor, sealed and placed in a forced air drying oven, and reacted at 200°C for 24 h; (3) After the reaction temperature drops to room temperature, centrifuge the precipitate, wash it three times with ethanol, and dry it at 90°C; (4) Pour the dried white sample into an ark and place it in the center of a tube furnace. Set the calcination temperature to 300 °C, the time to 3 h, the heating rate to 5 °C / min, and start calcination after argon is introduced for 30 min. After calcination, white powder NS-WO is obtained. 3 .

[0035] Example 5 A nitrogen-sulfur dual-doped WO 3 The method for preparing hollow spheres comprises the following steps: (1) Add 3 mmol of ammonium metatungstate to 3 mL of deionized water, dissolve it by ultrasonication, add 30 mL of n-pentanol and 32 mmol of thiourea, adjust the pH of the reaction solution to 2.0 with 3 mol / L of phosphoric acid while stirring, and obtain a white suspension after stabilization; (2) Transfer the white suspension into a 50 ml polytetrafluoroethylene stainless steel reactor, seal it and place it in a forced air drying oven, and react at 180 °C for 18 h; (3) After the reaction temperature drops to room temperature, centrifuge the precipitate, wash it three times with ethanol, and dry it at 80°C; (4) Pour the dried white sample into an ark and place it in the center of a tube furnace. Set the calcination temperature to 400 °C, the time to 2 h, the heating rate to 8 °C / min, and start calcination after nitrogen is introduced for 30 min. After calcination, a white powdery NS-WO is obtained. 3 .

[0036] Example 6 A nitrogen-sulfur dual-doped WO 3 The method for preparing hollow spheres comprises the following steps: (1) Add 4 mmol of sodium tungstate to 5 mL of deionized water, dissolve it by ultrasonication, add 80 mL of ethylene glycol and 60 mmol of thiourea, and adjust the pH of the reaction solution to 2.5 with 3 mol / L acetic acid while stirring. After stabilization, a white suspension is obtained; (2) Transfer the white suspension into a 100ml polytetrafluoroethylene stainless steel reactor, seal it and place it in a forced air drying oven, and react at 200℃ for 20h; (3) After the reaction temperature drops to room temperature, centrifuge the precipitate, wash it three times with ethanol, and dry it at 80°C; (4) Pour the dried white sample into an ark and place it in the center of a tube furnace. Set the calcination temperature to 350 °C, the time to 2 h, the heating rate to 8 °C / min, and start calcination after nitrogen is introduced for 30 min. After calcination, a white powdery NS-WO is obtained. 3 .

[0037] Example 7 A nitrogen-sulfur dual-doped WO 3 The method for preparing hollow spheres comprises the following steps: (1) Add 3 mmol of sodium tungstate to 2.5 mL of deionized water, dissolve it by ultrasonication, add 30 mL of 1:1 ethylene glycol and ethanol, and 30 mmol of thiourea, and adjust the pH of the reaction solution to 1.5 with 4 mol / L hydrochloric acid and nitric acid while stirring. After stabilization, a white suspension is obtained; (2) Transfer the white suspension into a 50 ml polytetrafluoroethylene stainless steel reactor, seal it and place it in a forced air drying oven, and react at 200 °C for 24 h; (3) After the reaction temperature drops to room temperature, centrifuge the precipitate, wash it three times with ethanol, and dry it at 90°C; (4) Pour the dried white sample into an ark and place it in the center of a tube furnace. Set the calcination temperature to 350 °C, the time to 2 h, the heating rate to 6 °C / min, and start calcination after nitrogen is introduced for 30 min. After calcination, a white powdery NS-WO is obtained. 3 .

Claims

1. A nitrogen-sulfur co-doped WO3 hollow sphere, characterized in that: Its chemical formula is NS-WO3, and it has excellent electrochemical properties with a specific capacity greater than 400 F / g. The band gap of the WO3 hollow sphere doped with nitrogen and sulfur is reduced from the commercial 2.72eV to below 2.60 eV, and the recombination rate of photogenerated electrons is significantly reduced.

2. The method for preparing nitrogen-sulfur co-doped WO3 hollow spheres according to claim 1, characterized in that The steps include: (1) ultrasonically dissolve the tungsten source in deionized water, then add alcohol solvent and thiourea, and adjust the pH value of the reaction solution to the acidic range with 2-5 mol / L protonic acid under stirring, and obtain a white suspension after stabilization; (2) The white suspension obtained in step (1) is poured into a 50 mL to 1000 mL polytetrafluoroethylene stainless steel reactor, which is sealed and placed in a forced air drying oven. The reaction temperature is controlled at 150° C. to 250° C. and the reaction time is controlled at 15 h to 30 h. After the reaction is completed, the temperature is lowered to room temperature, and the precipitate is washed with ethanol by centrifugation. After drying at 50° C. to 100° C., the precipitate is calcined at 250° C. to 450° C. in an inert atmosphere for 2 h to 5 h to obtain nitrogen-sulfur co-doped WO3 hollow spheres.

3. The method for preparing nitrogen-sulfur co-doped WO3 hollow spheres according to claim 2, characterized in that: The tungsten source described in step (1) is a water-soluble tungstate, selected from any one of sodium tungstate, ammonium tungstate, ammonium metatungstate and ammonium paratungstate.

4. The method for preparing nitrogen-sulfur co-doped WO3 hollow spheres according to claim 2, characterized in that: The alcohol solvent described in step (1) is any one or more selected from ethanol, n-propanol, isopropanol, n-butanol, isobutanol, n-pentanol, n-hexanol, n-octanol, glycerol, benzyl alcohol, and ethylene glycol.

5. The method for preparing nitrogen-sulfur co-doped WO3 hollow spheres according to claim 2, characterized in that: The protonic acid in step (1) is selected from any one or more of hydrochloric acid, nitric acid, sulfuric acid and acetic acid.

6. The method for preparing nitrogen-sulfur co-doped WO3 hollow spheres according to claim 2, characterized in that: The molar ratio of tungsten source: thiourea: deionized water: alcohol solvent in step (1) is 1:10-30:50-80:150-350, and the pH of the solution is adjusted to 1.5-2.5 by protonic acid.

7. The method for preparing nitrogen-sulfur co-doped WO3 hollow spheres according to claim 2, characterized in that: In step (2), the volume range of the polytetrafluoroethylene stainless steel reactor is 50 mL to 500 mL, the reaction temperature is 190° C. to 210° C., the reaction time is 18 h to 24 h, the precipitate is washed with ethanol 2 to 3 times, and the drying temperature is 60° C. to 90° C.

8. The method for preparing nitrogen-sulfur co-doped WO3 hollow spheres according to claim 2, characterized in that: In step (2), the inert atmosphere includes one or both of nitrogen and argon, the calcination temperature is 300° C. to 400° C., the heating rate is 5 to 8° C. / min, and the calcination time is 2 h to 3 h.

9. Use of the nitrogen-sulfur dual-doped WO3 hollow sphere as claimed in claim 1 in photoelectric reaction.

10. The use of nitrogen-sulfur dual-doped WO3 hollow spheres in photoelectric reaction according to claim 9, characterized in that: Nitrogen-sulfur co-doped WO3 hollow spheres showed better activity than commercial WO3 particles in the visible light photocatalytic degradation of organic pollutants acridine orange and methylene blue, completing the degradation of 98% of 20 mg / L acridine orange and methylene blue within 25 min and 17.5 min, respectively.

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