A non-stoichiometric Bi 3.84 W 0.16 O 6.24 Method for preparing photocatalyst and application thereof

Abstract

The application provides a non-stoichiometric ratio Bi 3.84 W 0.16 O 6.24 The application provides a preparation method and application of a photocatalyst, and the preparation method comprises the following steps: dissolving bismuth nitrate pentahydrate in acetic acid, uniformly mixing and stirring at room temperature to form a reaction liquid a; adding a water-soluble polymer dispersant into an aqueous solution of sodium tungstate dihydrate, uniformly mixing and stirring at room temperature to form a mixed solution b; adding the mixed solution b into the reaction liquid a, then adding a sodium hydroxide solution drop by drop to adjust the mixed solution to different pH values, maintaining a coprecipitation reaction, washing the product after the reaction is completed, and drying. 3.84 W 0.16 O 6.24 The photocatalyst has good visible light response ability, strong photocatalytic performance, and the photocatalytic performance on organic pollutants is obviously enhanced, so the photocatalyst has a wide application prospect in the field of wastewater treatment.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of photocatalytic materials, and particularly relates to a non-stoichiometric Bi 3.84 W 0.16 O 6.24 and application of a preparation method of the photocatalyst. BACKGROUND

[0002] At present, photocatalytic technology is considered as one of the technologies with great development potential in environmental remediation. The application of bismuth and its complexes has a history of more than two hundred years, and the technology is mature and stable. Bismuth-based photocatalysts are a kind of semiconductor materials with great prospects. Due to the hybridization of Bi6s and O2p orbitals, the position of the valence band of the bismuth-based photocatalyst is improved. The bismuth-based photocatalyst has a relatively narrow band gap and is more easily excited by visible light. In addition, the bismuth-based complex has low environmental impact and low price. Therefore, the bismuth-based photocatalyst has always been a popular research direction in the field of photocatalysis.

[0003] Bi 3.84 W 0.16 O 6.24 is a member of bismuth-based photocatalysts and has the advantages of bismuth-based photocatalysts. In addition, since it belongs to a non-stoichiometric compound, it has excellent optical and electrochemical properties due to the existence of crystal defects. At present, the research on Bi 3.84 W 0.16 O 6.24 is less at home and abroad, so it is of important theoretical significance and practical value to synthesize non-stoichiometric Bi 3.84 W 0.16 O 6.24 . SUMMARY

[0004] The application provides a preparation method of a non-stoichiometric Bi 3.84 W 0.16 O 6.24 photocatalyst and application, and the non-stoichiometric Bi 3.84 W 0.16 O 6.24 photocatalyst is obtained by a coprecipitation method, and has high efficient catalytic degradation performance on organic dyes.

[0005] In order to achieve the above purpose, the technical scheme is as follows:

[0006] The application provides a preparation method of a non-stoichiometric Bi 3.84 W 0.16 O 6.24 photocatalyst, which comprises the following steps:

[0007] Bismuth nitrate pentahydrate is dissolved in acetic acid, and stirred at room temperature to form a reaction solution a; a water-soluble polymer dispersant is added into an aqueous solution of sodium tungstate dihydrate, and stirred at room temperature to form a mixed solution b; the mixed solution b is added dropwise into the reaction solution a, and then a sodium hydroxide solution is added dropwise to adjust the pH of the mixed solution to different values, and the coprecipitation reaction is maintained until the reaction is completed, and then the product is washed and dried.

[0008] Preferably, the molar ratio of the bismuth nitrate pentahydrate to the sodium tungstate dihydrate is 2:1.

[0009] More preferably, the molar volume ratio (mol / L) of the bismuth nitrate pentahydrate to the acetic acid is 2:5; and / or the molar volume ratio (mol / L) of the sodium tungstate dihydrate to the water is 1:5.

[0010] Preferably, the water-soluble polymer dispersant is sodium dodecyl benzene sulfonate (SDBS), and the molar ratio of the sodium dodecyl benzene sulfonate to the sodium tungstate dihydrate is 0.025:1.

[0011] Preferably, the pH of the mixed solution adjusted by the sodium hydroxide solution is 11-13, and more preferably, the pH is 12.

[0012] More preferably, the concentration of the sodium hydroxide solution is 0.2 mol / L.

[0013] Preferably, the coprecipitation reaction time is 10 min-2 h, and more preferably, the coprecipitation reaction time is 2 h.

[0014] The application further provides a non-stoichiometric Bi 3.84 W 0.16 O 6.24 The application further provides an application of the photocatalyst, which comprises: adding the Bi 3.84 W 0.16 O 6.24 The photocatalyst reaches an adsorption-desorption equilibrium under dark conditions, and then performs a photocatalytic reaction under a visible light wavelength range to remove the basic fluorescent dye.

[0015] Preferably, the Bi 3.84 W 0.16 O 6.24 The addition amount of the photocatalyst in the aqueous solution of the basic fluorescent dye is 0.4 mg / mL.

[0016] More preferably, the aqueous solution of the basic fluorescent dye contains 10 mg / L of the basic fluorescent dye; and / or the basic fluorescent dye is rhodamine B.

[0017] Preferably, the visible light wavelength range is at least 420 nm; and the photocatalytic reaction is performed at room temperature.

[0018] The beneficial technical effects of the present application are that:

[0019] (1) The present application is prepared by co-precipitation method, Bi 3.84 W 0.16 O 6.24 The synthesis process of the photocatalyst consumes less time, energy and cost. It is suitable for industrial mass production, and the obtained Bi 3.84 W 0.16 O 6.24 As a photocatalyst, it has wide application prospects in the field of wastewater treatment.

[0020] (2) The Bi 3.84 W 0.16 O 6.24 The photocatalyst has obvious photocatalytic enhancement on organic pollutants, and can quickly remove organic pollutants in water.

[0021] (3) The Bi 3.84 W 0.16 O 6.24 The photocatalyst has good visible light response ability, strong photocatalytic performance, excellent recycling performance after desorption, and stable state. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 are X-ray diffraction (XRD) patterns of the present application examples 1, 2 and 3.

[0023] Figure 2 are ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS) patterns of the present application examples 1, 2 and 3.

[0024] Figure 3 is a scanning electron microscope (SEM) pattern of the present application example 2.

[0025] Figure 4 are degradation performance patterns of rhodamine B in a visible light catalytic system of the present application examples 1, 2 and 3.

[0026] Figure 5 are degradation performance patterns of rhodamine B in a visible light catalytic system of the present application comparative examples 1, 2 and 3.

[0027] Figure 6 are degradation performance patterns of rhodamine B in a visible light catalytic system of the present application examples 4, 5 and 6. DETAILED DESCRIPTION

[0028] In order to more clearly illustrate the present application, the present application will be further described in detail below with reference to the embodiments and in conjunction with the drawings. It should be understood by those skilled in the art that the specific description below is illustrative rather than limiting, and should not limit the scope of protection of the present application.

[0029] In the present application, "room temperature" can be "25℃±5℃".

[0030] Example 1

[0031] A non-stoichiometric Bi 3.84 W 0.16 O 6.24 A preparation method of a photocatalyst, comprising the following steps:

[0032] (1) 4mmol of bismuth nitrate pentahydrate is weighed and dissolved in 10mL of acetic acid solution, and stirred for half an hour at room temperature to completely dissolve;

[0033] (2) 2mmol of sodium tungstate dihydrate and 0.05mmol of SDBS are weighed and dissolved in 10mL of water solution, and stirred for half an hour at room temperature to completely dissolve;

[0034] (3) The solution obtained in step (2) is slowly added to the solution in step (1), and after completion, 0.2mol / L sodium hydroxide solution is added to adjust the pH of the solution to 11, and then the co-precipitation reaction is maintained for 2h;

[0035] (4) After the co-precipitation reaction is completed, multiple water washing and alcohol washing are performed, and the product is placed in a vacuum oven at 60℃ for drying for 12h to obtain Bi 3.84 W 0.16 O 6.24 The photocatalyst is denoted as BWOpH=11.

[0036] Example 2

[0037] A non-stoichiometric Bi 3.84 W 0.16 O 6.24 A preparation method of a photocatalyst, comprising the following steps:

[0038] (1) 4mmol of bismuth nitrate pentahydrate is weighed and dissolved in 10mL of acetic acid solution, and stirred for half an hour at room temperature to completely dissolve;

[0039] (2) 2mmol of sodium tungstate dihydrate and 0.05mmol of SDBS are weighed and dissolved in 10mL of water solution, and stirred for half an hour at room temperature to completely dissolve;

[0040] (3) slowly drop the solution obtained in step (2) into the solution in step (1), after completion, drop 0.2 mol / L sodium hydroxide solution to adjust the solution pH=12, then maintain the co-precipitation reaction for 2 h;

[0041] (4) after the co-precipitation reaction, through multiple water washing and alcohol washing, put into a vacuum oven for drying at 60℃ for 12 h, to obtain Bi 3.84 W 0.16 O 6.24 photocatalyst, recorded as BWOpH=12.

[0042] Example 3

[0043] a non-stoichiometric Bi 3.84 W 0.16 O 6.24 photocatalyst preparation method, comprising the following steps:

[0044] (1) weigh 4 mmol bismuth nitrate pentahydrate and dissolve in 10 mL acetic acid solution, under room temperature condition, stir for half an hour to make it completely dissolved;

[0045] (2) weigh 2 mmol sodium tungstate dihydrate, 0.05 mmol SDBS and dissolve in 10 mL water solution, under room temperature condition, stir for half an hour to make it completely dissolved;

[0046] (3) slowly drop the solution obtained in step (2) into the solution in step (1), after completion, drop 0.2 mol / L sodium hydroxide solution to adjust the solution pH=13, then maintain the co-precipitation reaction for 2 h;

[0047] (4) after the co-precipitation reaction, through multiple water washing and alcohol washing, put into a vacuum oven for drying at 60℃ for 12 h, to obtain Bi 3.84 W 0.16 O 6.24 photocatalyst, recorded as BWOpH=13.

[0048] X-ray diffraction is performed on the Bi 3.84 W 0.16 O 6.24 photocatalysts prepared in Examples 1, 2 and 3, and the obtained XRD spectrum is as shown in Figure 1 Compared with the standard diffraction powder card, the diffraction peaks and intensity are basically consistent with the standard card, the obtained Bi 3.84 W 0.16 O 6.24 photocatalyst has high purity, with the increase of pH, the peak intensity of the Bi 3.84 W 0.16 O 6.24 photocatalyst is enhanced, and the peak shape is more sharp.

[0049] Bi prepared in Examples 1, 2, and 3 3.84 W 0.16 O 6.24 The photocatalyst was subjected to UV-Vis diffuse reflectance spectroscopy. The UV-Vis diffuse reflectance spectrum is shown below. Figure 2 As shown, the visible light absorption range of Example 2 is wider than that of Examples 1 and 3, indicating that Example 2 has stronger light absorption capability in the visible light region. This demonstrates that it can utilize more visible light, which is beneficial for improving photocatalytic performance.

[0050] Continue with the Bi prepared in Example 2 3.84 W 0.16 O 6.24 The photocatalyst was subjected to SEM testing. The SEM image is shown below. Figure 3 As shown, Example 2 exhibits a flower cluster-like structure. It demonstrates good dispersibility.

[0051] Example 4

[0052] A non-stoichiometric ratio Bi 3.84 W 0.16 O 6.24 The preparation method of photocatalyst includes the following steps:

[0053] (1) Weigh 4 mmol of bismuth nitrate pentahydrate and dissolve it in 10 mL of acetic acid solution. Stir for half an hour at room temperature until it is completely dissolved.

[0054] (2) Weigh 2 mmol sodium tungstate dihydrate and 0.05 mmol SDBS and dissolve them in 10 mL of aqueous solution. Stir for half an hour at room temperature until completely dissolved.

[0055] (3) Slowly add the solution obtained in step (2) to the solution described in step (1), and after completion, add 0.2 mol / L sodium hydroxide solution to adjust the pH of the solution to 12. Then maintain the coprecipitation reaction for 10 min;

[0056] (4) After the coprecipitation reaction was completed, the sample was washed with water and alcohol several times, and then dried in a vacuum oven at 60°C for 12 hours to obtain Bi. 3.84 W 0.16 O 6.24 The photocatalyst is designated BWO-10min pH=12.

[0057] Example 5

[0058] A non-stoichiometric ratio Bi 3.84 W 0.16 O 6.24 The preparation method of photocatalyst includes the following steps:

[0059] (1) 4 mmol of bismuth nitrate pentahydrate was weighed and dissolved in 10 mL of acetic acid solution, and stirred at room temperature for half an hour to completely dissolve;

[0060] (2) 2 mmol of sodium tungstate dihydrate and 0.05 mmol of SDBS were weighed and dissolved in 10 mL of water solution, and stirred at room temperature for half an hour to completely dissolve;

[0061] (3) The solution obtained in step (2) was slowly added to the solution in step (1), and after completion, 0.2 mol / L sodium hydroxide solution was added to adjust the pH of the solution to 12. Then the co-precipitation reaction was maintained for 30 min;

[0062] (4) After the co-precipitation reaction was completed, multiple water washing and alcohol washing were performed, and the product was placed in a vacuum oven at 60°C for drying for 12 h to obtain Bi 3.84 W 0.16 O 6.24 The photocatalyst is recorded as BWO-30minpH=12.

[0063] Example 6

[0064] A preparation method of a non-stoichiometric Bi 3.84 W 0.16 O 6.24 photocatalyst, comprising the following steps:

[0065] (1) 4 mmol of bismuth nitrate pentahydrate was weighed and dissolved in 10 mL of acetic acid solution, and stirred at room temperature for half an hour to completely dissolve;

[0066] (2) 2 mmol of sodium tungstate dihydrate and 0.05 mmol of SDBS were weighed and dissolved in 10 mL of water solution, and stirred at room temperature for half an hour to completely dissolve;

[0067] (3) The solution obtained in step (2) was slowly added to the solution in step (1), and after completion, 0.2 mol / L sodium hydroxide solution was added to adjust the pH of the solution to 12. Then the co-precipitation reaction was maintained for 1 h;

[0068] (4) After the co-precipitation reaction was completed, multiple water washing and alcohol washing were performed, and the product was placed in a vacuum oven at 60°C for drying for 12 h to obtain Bi 3.84 W 0.16 O 6.24 The photocatalyst is recorded as BWO-1hpH=12.

[0069] Comparative Example 1

[0070] A preparation method of a non-stoichiometric Bi 3.84 W 0.16 O 6.24 photocatalyst, comprising the following steps:

[0071] (1) 4 mmol of bismuth nitrate pentahydrate was weighed and dissolved in 10 mL of acetic acid solution, and stirred at room temperature for half an hour to completely dissolve;

[0072] (2) 2 mmol of sodium tungstate dihydrate was weighed and dissolved in 10 mL of water solution without adding SDBS, and stirred at room temperature for half an hour to completely dissolve;

[0073] (3) The solutions obtained in steps (1) and (2) were mixed and fully stirred, and after completion, 0.2 mol / L sodium hydroxide solution was added dropwise to adjust the solution pH to 11. Subsequently, it was loaded into a hydrothermal reaction kettle for solvothermal reaction at 120°C for 2h;

[0074] (4) After the solvothermal reaction was completed, it was washed with water and alcohol for multiple times, and was placed in a vacuum oven at 60°C for drying for 12h to obtain Bi 3.84 W 0.16 O 6.24 The photocatalyst is recorded as BWO-ApH=11.

[0075] Comparative Example 2

[0076] A non-stoichiometric Bi 3.84 W 0.16 O 6.24 The preparation method of the photocatalyst comprises the following steps:

[0077] (1) 4 mmol of bismuth nitrate pentahydrate was weighed and dissolved in 10 mL of acetic acid solution, and stirred at room temperature for half an hour to completely dissolve;

[0078] (2) 2 mmol of sodium tungstate dihydrate was weighed and dissolved in 10 mL of water solution without adding SDBS, and stirred at room temperature for half an hour to completely dissolve;

[0079] (3) The solutions obtained in steps (1) and (2) were mixed and fully stirred, and after completion, 0.2 mol / L sodium hydroxide solution was added dropwise to adjust the solution pH to 12. Subsequently, it was loaded into a hydrothermal reaction kettle for solvothermal reaction at 120°C for 2h;

[0080] (4) After the solvothermal reaction was completed, it was washed with water and alcohol for multiple times, and was placed in a vacuum oven at 60°C for drying for 12h to obtain Bi 3.84 W 0.16 O 6.24 The photocatalyst is recorded as BWO-ApH=12.

[0081] Comparative Example 3

[0082] A non-stoichiometric Bi 3.84 W 0.16 O 6.24A method for preparing a photocatalyst, comprising the following steps:

[0083] (1) 4 mmol of bismuth nitrate pentahydrate was weighed and dissolved in 10 mL of acetic acid solution, and stirred at room temperature for half an hour to completely dissolve;

[0084] (2) 2 mmol of sodium tungstate dihydrate was weighed and dissolved in 10 mL of water solution, without adding SDBS, and stirred at room temperature for half an hour to completely dissolve;

[0085] (3) The solutions obtained in steps (1) and (2) were mixed and fully stirred, and then 0.2 mol / L sodium hydroxide solution was added dropwise to adjust the pH of the solution to 13. Subsequently, the solution was loaded into a hydrothermal reaction kettle and subjected to solvothermal reaction at 120°C for 2 h;

[0086] (4) After the solvothermal reaction was completed, the product was washed with water and alcohol for multiple times, and then placed in a vacuum oven at 60°C for drying for 12 h to obtain Bi 3.84 W 0.16 O 6.24 The photocatalyst is denoted as BWO-ApH=13.

[0087] Application Example

[0088] The Bi 3.84 W 0.16 O 6.24 photocatalysts prepared in the above examples 1-6 and comparative examples 1-3 were subjected to photocatalytic degradation experiment of rhodamine B under visible light catalytic system. The amount of simulated wastewater was 40 mL. A xenon lamp was used as light source, and dark reaction was carried out for 40 min to reach adsorption-desorption equilibrium, and light reaction was carried out for 120 min, and 3 mL of sample was taken out every 10 min, centrifuged at 4000 rpm for 3 min, and determined and recorded at the maximum absorption wavelength of 554 nm using ultraviolet-visible spectrophotometer. The degradation efficiency was expressed as C / C0, wherein C represents the concentration of sample at different time periods, and C0 represents the concentration of sample in initial state. Figure 4 The degradation performance of rhodamine B in visible light catalytic system for examples 1, 2 and 3 is shown in the figure. Figure 5 The degradation performance of rhodamine B in visible light catalytic system for comparative examples 1, 2 and 3 is shown in the figure. Figure 6 The degradation performance of rhodamine B in visible light catalytic system for examples 4, 5 and 6 is shown in the figure.

[0089] In combination with Figure 4 , Figure 5 , Figure 6 and Table 1, it can be seen that the photocatalytic performance of examples 1-6 on rhodamine B is better than that of comparative examples under the irradiation of visible light source, and the photocatalytic performance of example 2 on rhodamine B is the best. Figure 4(b) indicates that the degradation rate of example 2 on RhB is 0.0365min -1 , which is 6.2 times of example 1 and 3.1 times of example 3. After 120 min of light reaction, the degradation rate of RhB reached 98.59%, which was basically completely degraded. This proves that the addition of SDBS is beneficial, and the co-precipitation reaction time has a certain influence on the photocatalytic performance of Bi 3.84 W 0.16 O 6.24 .

[0090] Table 1 Bi 3.84 W 0.16 O 6.24 photocatalyst on rhodamine B

[0091]

[0092]

[0093] In summary, the Bi 3.84 W 0.16 O 6.24 photocatalyst prepared by co-precipitation method with the assistance of SDBS has a wide visible light response range, strong visible light response ability, and can efficiently photocatalyze and remove organic pollutants.

[0094] Obviously, the above examples of the present application are only examples for more clearly illustrating the present application, and are not a limitation on the embodiments of the present application. For ordinary skilled in the art, on the basis of the above description, other different forms of changes or variations can also be made, and here it is impossible to enumerate all the implementation methods, and any changes or variations that belong to the technical solutions of the present application still fall within the protection scope of the present application.

Claims

1. A non-stoichiometric Bi2S3 3.84 W 0.16 O 6.24 A method for preparing a photocatalyst, comprising: Bismuth nitrate pentahydrate is dissolved in acetic acid, mixed and stirred at room temperature to form a reaction liquid a, the molar volume ratio of bismuth nitrate pentahydrate to acetic acid is 2:5; a water-soluble polymer dispersant is added into an aqueous solution of sodium tungstate dihydrate, mixed and stirred at room temperature to form a mixed solution b, the molar volume ratio of sodium tungstate dihydrate to water is 1:5, the water-soluble polymer dispersant is sodium dodecyl benzene sulfonate, the molar ratio of sodium dodecyl benzene sulfonate to sodium tungstate dihydrate is 0.025:1; the mixed solution b is added dropwise into the reaction liquid a, then a sodium hydroxide solution is added dropwise to adjust the pH of the mixed solution to 12, a coprecipitation reaction is maintained, the coprecipitation reaction time is 2h, after the reaction is completed, the product is washed and dried, the molar ratio of bismuth nitrate pentahydrate to sodium tungstate dihydrate is 2:

1.

2. A non-stoichiometric Bi2S3 prepared by the method of claim 1. 3.84 W 0.16 O 6.24 The use of the photocatalyst includes: adding Bi to an aqueous solution of a basic fluorescent dye 3.84 W 0.16 O 6.24 photocatalyst, after reaching adsorption-desorption equilibrium in dark conditions, carries out a photocatalytic reaction in the visible wavelength range to achieve removal of the basic fluorescent dye, the basic fluorescent dye being rhodamine B, the visible wavelength range being at least 420 nm; the photocatalytic reaction is carried out at room temperature.

3. Use according to claim 2, characterized in that, The Bi 3.84 W 0.16 O 6.24 The dosage of the photocatalyst in the aqueous solution of the basic fluorescent dye is 0.4 mg / mL.

4. Use according to claim 2, characterized in that, The aqueous solution of the basic fluorescent dye contains 10 mg / L of the basic fluorescent dye.

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