A kind of Bi 0.5 Na 0.5 Preparation methods and applications of TiO3 / MoSe2 composite catalysts

Abstract

This invention belongs to the field of piezoelectric photocatalysts, specifically relating to a Bi 0.5 Na 0.5 Preparation method and application of TiO3 / MoSe2 composite catalyst. This invention uses Bi... 0.5 Na 0.5 Bi with a Z-shaped heterostructure was synthesized using TiO3 and MoSe2 as raw materials and ethanol solution as solvent via a simple impregnation and stirring method. 0.5 Na 0.5 TiO3 / MoSe2 composite catalyst. The catalyst prepared in this invention, under the synergistic effect of light and ultrasound, exhibits a catalytic H2 production rate that is [missing information - likely related to Bi]. 0.5 Na 0.5 The piezoelectric photocatalytic performance of the catalyst is 28 times and 36 times that of TiO3 and MoSe2, respectively, which is significantly improved. The synthesis method of this invention is simple, green, pollution-free, and highly operable. The prepared catalyst has abundant active sites and excellent stability, and does not produce secondary pollution.

Description

Technical Field

[0001] This invention belongs to the field of photocatalysis technology, specifically relating to a Bi 0.5 Na 0.5 Preparation method and application of TiO3 / MoSe2 composite catalyst. Background Technology

[0002] Photocatalytic hydrogen production has garnered increasing attention due to its potential to alleviate the energy crisis. However, the rapid recombination of photogenerated electrons and holes leads to low photocatalytic efficiency, limiting the practical application of photocatalysis technology. In recent years, piezoelectric photocatalysis has emerged as a promising field because its built-in electric field can promote the efficient separation of excitons upon mechanical stimulation, thereby improving hydrogen production performance. Perovskite-structured Bi 0.5 Na 0.5 TiO3 possesses excellent piezoelectric properties, low toxicity, and high structural stability, making it a highly promising lead-free piezoelectric material. More importantly, unlike other commonly studied piezoelectric materials, Bi... 0.5 Na 0.5 TiO3's relatively high conductivity is crucial for effective charge transport, making it the best choice for catalytic applications.

[0003] Bi 0.5 Na 0.5 TiO3 possesses a suitable band structure, controllable morphology, and strong light absorption capacity, making it applicable in the field of electro-photocatalysis. For example, patent CN202110438467.4 discloses a sodium bismuth titanate / graphite phase carbon nitride heterojunction piezoelectric photocatalyst and its preparation method, but the preparation method is cumbersome and the hydrogen production efficiency is not high. Summary of the Invention

[0004] The purpose of this invention is to provide a Bi 0.5 Na 0.5 A method for preparing TiO3 / MoSe2 composite catalyst was presented, and its application in photocatalytic H2 production was demonstrated, exhibiting high catalytic activity and good stability.

[0005] The technical solution of the present invention: The Bi provided by the present invention 0.5 Na 0.5 The preparation method of TiO3 / MoSe2 composite catalyst is as follows:

[0006] (1)Bi 0.5 Na 0.5 Preparation of TiO3

[0007] BiCl3 and TiO2 were added to a NaOH solution and magnetically stirred for 2–4 hours to form a homogeneous suspension. The suspension was transferred to a polytetrafluoroethylene-lined autoclave and heated in an oven at 180–220°C for 40–50 hours. After naturally cooling to room temperature, the mixture was thoroughly rinsed with deionized water and anhydrous ethanol, and dried at 80°C for 24 hours to obtain a white powder, which is BiCl3. 0.5 Na 0.5 TiO3.

[0008] Furthermore, the mass ratio of BiCl3 to TiO2 is (2-3):(1-2).

[0009] Furthermore, the concentration of the NaOH solution is 14–16 mol / L.

[0010] (2) Preparation of MoSe2

[0011] NaBH4 and Se powder were dissolved in deionized water, and then Na2MoO4 was added. The mixture was magnetically stirred for 15–20 min to form a uniform suspension. The suspension was transferred to a polytetrafluoroethylene-lined autoclave and heated in an oven at 200–240 °C for 15–20 h. After cooling to room temperature, the mixture was thoroughly rinsed with deionized water and anhydrous ethanol, and then vacuum dried at 60 °C for 24 h to obtain a black powder, which is MoSe2.

[0012] Furthermore, the mass ratio of NaBH4, Se powder, and Na2MoO4 is (0.2-0.6):(0.2-0.6):(0.3-0.7).

[0013] (3)Bi 0.5 Na 0.5 Preparation of TiO3 / MoSe2 composite catalyst:

[0014] Bi 0.5 Na 0.5 TiO3 and MoSe2 were dispersed in an alcohol solution, subjected to ultrasonication and stirring, centrifuged at room temperature, washed, and dried to obtain a gray powder, which is Bi. 0.5 Na 0.5 TiO3 / MoSe2 composite catalyst.

[0015] Furthermore, the mass of the MoSe2 is Bi. 0.5 Na 0.5 TiO3 content is 3-7% of its mass.

[0016] Furthermore, the mass of the MoSe2 is Bi. 0.5 Na 0.5 TiO3 content is 5-7% of its mass.

[0017] Furthermore, the concentration of the ethanol solution is 90–99.9 wt%.

[0018] Furthermore, the ultrasonic power is 240W and the ultrasonic time is 30min.

[0019] Furthermore, the stirring speed is 400 r / min, and the stirring time is 24 h.

[0020] The Bi obtained above 0.5 Na 0.5 The application of TiO3 / MoSe2 composite catalyst in piezoelectric photocatalytic H2 production includes the following steps: Weighing Bi 0.5 Na 0.5 The TiO3 / MoSe2 composite catalyst was added to deionized water, ultrasonically dispersed, then methanol was added, and N2 was introduced. The mixture was then sealed and subjected to H2 production under the combined conditions of ultrasound and light irradiation.

[0021] Furthermore, the ultrasonic power is 240W and the ultrasonic time is 30min.

[0022] Furthermore, the stirring speed is 400 r / min, and the stirring time is 24 h.

[0023] Furthermore, the volume ratio of methanol to deionized water is 1:9.

[0024] The beneficial effects of this invention are as follows:

[0025] (1) This invention uses Bi 0.5 Na 0.5 Bi with a Z-shaped heterostructure was synthesized using TiO3 and MoSe2 as raw materials and ethanol solution as solvent via a simple impregnation and stirring method. 0.5 Na 0.5 The TiO3 / MoSe2 composite catalyst has simple synthesis conditions, is easy to operate, and has the characteristics of being fast, efficient, energy-saving and environmentally friendly.

[0026] (2) The introduction of MoSe2 did not change Bi 0.5 Na 0.5 The crystal structure of TiO3 showed no other diffraction peaks, indicating that Bi... 0.5 Na 0.5 The TiO3 / MoSe2 composite material exhibits excellent crystallinity and purity, indicating superior stability.

[0027] (3) Bi prepared by the present invention 0.5 Na 0.5The TiO3 / MoSe2 composite catalyst has a Z-type heterojunction structure. Under ultrasonic vibration, an internal polarized electric field (P0) is generated, driving electron-hole transfer and creating positive and negative charges on both sides. Simultaneously, under illumination, electrons escape from Bi... 0.5 Na 0.5 The CB of TiO3 is transferred to the VB of MoSe2, at which point the CB and Bi of MoSe2 are also transferred. 0.5 Na 0.5 Electrons and holes accumulate in the VB of TiO3, while electrons in the CB of MoSe2 can reduce protons to H2. Bi 0.5 Na 0.5 Holes in the VB of TiO3 can be effectively removed using methanol as a sacrificial agent. Simultaneously, the generated polarization field acts as a driving force, preventing the recombination of electrons and holes, thereby improving piezoelectric photocatalytic performance and catalyst stability. (The last sentence appears to be incomplete and possibly refers to a different topic.) 0.5 Na 0.5 Bi was prepared under the condition of 5% TiO3 by mass. 0.5 Na 0.5 The hydrogen production performance of the TiO3 / MoSe2 composite catalyst is that of Bi 0.5 Na 0.5 The efficiency of hydrogen production is 28 times and 36 times that of TiO3 and MoSe2 catalysts, respectively, and after four cycles, the efficiency of hydrogen production only decreases by 3%. Attached image description:

[0028] Figure 1 Bi synthesized in Example 1 0.5 Na 0.5 Scanning electron microscope image of the TiO3 / MoSe2 composite catalyst;

[0029] Figure 2 These are XRD patterns of the catalysts prepared in Examples 1-3, Comparative Examples 7 and 10.

[0030] Figure 3 The graphs show the H2 production performance of the catalysts prepared in Examples 1-3, Comparative Examples 7 and 10 under the action of ultrasound and light.

[0031] Figure 4 The graphs show the H2 production performance of the catalysts prepared under ultrasonic treatment in Examples 1-3, Comparative Examples 7 and 10.

[0032] Figure 5 The graphs show the H2 production performance of the catalysts prepared under light irradiation in Examples 1-3, Comparative Examples 7 and 10.

[0033] Figure 6 The graph shows the performance of the catalysts prepared in Example 1 for H2 production under different sacrificial agents;

[0034] Figure 7 This is a diagram showing the cyclic effect of H2 production by the catalyst prepared in Example 1. Detailed Implementation

[0035] This invention is not limited to the specific embodiments listed below. Those skilled in the art can implement this invention using various other specific embodiments based on the content disclosed herein. Any modifications or alterations made to the design structure and concept of this invention fall within the protection scope of this invention. It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0036] The H2 production efficiency is calculated using the following formula:

[0037]

[0038] R: H2 production rate, unit: μmol / (g·h)

[0039] V: Volume of hydrogen gas, unit: μL

[0040] m: Catalyst mass, unit: g

[0041] t: Reaction time, unit: h

[0042] Example 1

[0043] BiCl3 and TiO2 in a mass ratio of 2:1 were added to 50 mL of NaOH solution (15 mol / L) and magnetically stirred for 2 h to form a homogeneous suspension. The suspension was transferred to a 100 mL polytetrafluoroethylene-lined autoclave and heated in an oven at 200 °C for 48 h. After naturally cooling to room temperature, the mixture was thoroughly rinsed with deionized water and anhydrous ethanol, and dried at 80 °C for 24 h to obtain a white powder, which is BiCl3. 0.5 Na 0.5 TiO3.

[0044] NaBH4, Se powder, and Na2MoO4 in a mass ratio of 3:3:5 were dissolved in 75 mL of deionized water and magnetically stirred for 20 min to form a homogeneous suspension. The suspension was transferred to a 100 mL polytetrafluoroethylene-lined autoclave and heated in an oven at 220 °C for 20 h. After cooling to room temperature, the mixture was thoroughly rinsed with deionized water and anhydrous ethanol, and then vacuum dried at 60 °C for 24 h to obtain a black powder, which is MoSe2.

[0045] Bi 0.5 Na 0.5 TiO3 and MoSe2 were dissolved in 95% ethanol solution, sonicated for 30 min, and stirred at 400 rpm for 24 h. After centrifugation, washing, and drying, a gray powder, Bi, was finally obtained.0.5 Na 0.5 The TiO3 / MoSe2 composite catalyst, with added MoSe2 having a mass ratio of Bi... 0.5 Na 0.5 5% of the mass of TiO3 is denoted as 5%Bi. 0.5 Na 0.5 TiO3 / MoSe2.

[0046] Application methods of composite catalysts:

[0047] Weigh 2mg of 5% Bi 0.5 Na 0.5 TiO3 / MoSe2 was mixed with 18 mL of water and ultrasonically dispersed for 0.5 h to ensure uniform dispersion of the catalyst. Then, 2 mL of methanol was added, followed by N2 purging for 0.5 h. Finally, the mixture was sealed for 2 h under ultrasonic (240 W) and light irradiation (55 W xenon lamp simulating sunlight). After the experiment, 0.5 mL of gas was extracted from the tube, and the peak area was detected using gas chromatography to calculate the H2 production rate. The calculated H2 production rate was 3365.94 μmol / (g·h).

[0048] Example 2

[0049] Compared with Example 1, the difference is that the mass of MoSe2 added during the preparation process is Bi. 0.5 Na 0.5 The TiO3 / MoSe2 content was 3% by mass, and other preparation methods were the same as in Example 1, resulting in Bi... 0.5 Na 0.5 The TiO3 / MoSe2 composite catalyst is designated as 3% Bi 0.5 Na 0.5 TiO3 / MoSe2.

[0050] The application method is the same as in Example 1 and Example 2 for the 3% Bi 0.5 Na 0.5 The H2 production rate of TiO3 / MoSe2 is 1316.55 μmol / (g·h).

[0051] Example 3

[0052] Compared with Example 1, the difference is that the mass of MoSe2 added during the preparation process is Bi. 0.5 Na 0.5 The TiO3 content was 7% by mass, and other preparation methods were the same as in Example 1, resulting in Bi... 0.5 Na 0.5 The TiO3 / MoSe2 composite catalyst is designated as 7% Bi 0.5 Na 0.5 TiO3 / MoSe2.

[0053] The application method is the same as in Example 1 and Example 3, which prepared 7% Bi 0.5 Na 0.5 The H2 production rate of TiO3 / MoSe2 is 2730.25 μmol / (g·h).

[0054] Comparative Example 1

[0055] Compared to Example 1, the difference is that the ultrasound (240W) + light (55W xenon lamp simulating sunlight) in the application method is changed to ultrasound only (240W), otherwise it is the same as Example 1. 5% Bi 0.5 Na 0.5 The H2 production rate of TiO3 / MoSe2 is 1181.41 μmol / (g·h).

[0056] Comparative Example 2

[0057] Compared to Example 1, the difference is that the ultrasound (240W) + light (55W xenon lamp simulating sunlight) in the application method is changed to light only (55W xenon lamp simulating sunlight), otherwise it is the same as Example 1. 5% Bi 0.5 Na 0.5 The H2 production rate of the TiO3 / MoSe2 catalyst is 118.95 μmol / (g·h).

[0058] Comparative Example 3

[0059] Compared to Example 2, the difference is that the ultrasound (240W) + light (55W xenon lamp simulating sunlight) in the application method is changed to ultrasound only (240W), otherwise it is the same as Example 2. 3% Bi 0.5 Na 0.5 The H2 production rate of the TiO3 / MoSe2 catalyst is 162.4 μmol / (g·h).

[0060] Comparative Example 4

[0061] Compared to Example 2, the difference is that the application method of ultrasound (240W) + light (55W xenon lamp simulating sunlight) is changed to light only (55W xenon lamp simulating sunlight), otherwise it is the same as Example 2. 3% Bi 0.5 Na 0.5 The H2 production rate of the TiO3 / MoSe2 catalyst is 55.93 μmol / (g·h).

[0062] Comparative Example 5

[0063] Compared to Example 3, the difference is that the ultrasound (240W) + light (55W xenon lamp simulating sunlight) in the application method is changed to ultrasound only (240W), otherwise it is the same as Example 3. 7% Bi 0.5 Na 0.5The H2 production rate of the TiO3 / MoSe2 catalyst is 730.74 μmol / (g·h).

[0064] Comparative Example 6

[0065] Compared to Example 3, the difference is that the application method of ultrasound (240W) + light (55W xenon lamp simulating sunlight) is changed to light only (55W xenon lamp simulating sunlight), otherwise it is the same as Example 3. 7% Bi 0.5 Na 0.5 The H2 production rate of the TiO3 / MoSe2 catalyst is 428.04 μmol / (g·h).

[0066] Comparative Example 7

[0067] BiCl3 and TiO2 in a mass ratio of 2:1 were added to 50 mL of NaOH solution (15 mol / L) and magnetically stirred for 2 h to form a homogeneous suspension. The suspension was transferred to a 100 mL polytetrafluoroethylene-lined autoclave and heated in an oven at 200 °C for 48 h. After naturally cooling to room temperature, the mixture was thoroughly rinsed with deionized water and anhydrous ethanol, and dried at 80 °C for 24 h to obtain a white powder, which is BiCl3. 0.5 Na 0.5 TiO3 catalyst.

[0068] Weigh out 2mg Bi 0.5 Na 0.5 TiO3 catalyst was added to 18 mL of water and ultrasonically dispersed for 0.5 h to ensure uniform dispersion. Then, 2 mL of methanol was added, followed by N2 purging for 0.5 h. Finally, the mixture was sealed for 2 h under ultrasonic (240 W) and light irradiation (55 W xenon lamp simulating sunlight). After the experiment, 0.5 mL of gas was extracted from the tube, and the peak area was detected using gas chromatography to calculate the H2 production rate. The calculated H2 production rate was 118.5 μmol / (g·h).

[0069] Comparative Example 8

[0070] Compared with Comparative Example 7, the difference is that the application method of ultrasound (240W) + light (55W xenon lamp simulating sunlight) is changed to ultrasound only (240W), otherwise it is the same as Comparative Example 7. 0.5 Na 0.5 The H2 production rate of the TiO3 catalyst is 14.46 μmol / (g·h).

[0071] Comparative Example 9

[0072] Compared with Comparative Example 7, the difference is that the application method of ultrasound (240W) + light (55W xenon lamp simulating sunlight) is changed to light only (55W xenon lamp simulating sunlight), otherwise it is the same as Comparative Example 7. 0.5Na 0.5 The H2 production rate of the TiO3 catalyst is 24.58 μmol / (g·h).

[0073] Comparative Example 10

[0074] NaBH4, Se powder, and Na2MoO4 in a mass ratio of 3:3:5 were dissolved in 75 mL of water and magnetically stirred for 20 min to form a homogeneous suspension. The suspension was transferred to a 100 mL polytetrafluoroethylene-lined autoclave and heated in an oven at 220 °C for 20 h. After cooling to room temperature, the mixture was thoroughly rinsed with deionized water and anhydrous ethanol and vacuum dried at 60 °C for 24 h to obtain a black powder, which is MoSe2.

[0075] Weigh 2 mg of MoSe2 catalyst, add 18 mL of water, and ultrasonically disperse for 0.5 h to ensure uniform dispersion of the catalyst in the water. Then add 2 mL of methanol, followed by purging with N2 for 0.5 h, and finally seal under ultrasonic (240 W) and light irradiation (55 W xenon lamp simulating sunlight) for 2 h. After the experiment, extract 0.5 mL of gas from the tube, detect the peak area using a gas chromatograph, and calculate the H2 production rate. The calculated H2 production rate is 103.01 μmol / (g·h).

[0076] Comparative Example 11

[0077] Compared with Comparative Example 10, the difference is that the application conditions were changed to ultrasound (240W), while other conditions remained the same as in Comparative Example 10. The H2 production rate of the MoSe2 catalyst was 11.71 μmol / (g·h).

[0078] Comparative Example 12

[0079] Compared to Comparative Example 10, the difference lies in the application conditions, which were changed to illumination (sunlight simulated by a 55W xenon lamp). Otherwise, the conditions remained the same as in Comparative Example 10. The H2 production rate of the MoSe2 catalyst was 20.78 μmol / (g·h).

[0080] Comparative Example 13

[0081] Compared with Example 1, the difference is that the sacrificial agent added is changed from methanol to ethanol; otherwise, it is the same as Example 1. 5% Bi 0.5 Na 0.5 The H2 production rate of TiO3 / MoSe2 is 1604.54 μmol / (g·h).

[0082] Comparative Example 14

[0083] Compared to Example 1, the difference is that the sacrificial agent added is changed from methanol to lactic acid; otherwise, it is the same as Example 1. 5% Bi 0.5 Na 0.5The H2 production rate of TiO3 / MoSe2 is 1247.21 μmol / (g·h).

[0084] Comparative Example 15

[0085] Compared to Example 1, the difference is that the sacrificial agent added is changed from methanol to triethanolamine; otherwise, it is the same as Example 1. 5% Bi 0.5 Na 0.5 The H2 production rate of TiO3 / MoSe2 is 1870.86 μmol / (g·h).

[0086] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A Bi 0.5 Na 0.5 TiO3 / MoSe2 composite catalyst for piezoelectric photocatalytic H2 production, characterized by comprising the steps of: MoSe2, Bi 0.5 Na 0.5 TiO3 is dissolved in an ethanol solution, after ultrasonic and stirring treatment, centrifugation, washing and drying, Bi 0.5 Na 0.5 TiO3 / MoSe2 composite catalyst is obtained. ​​ where the mass of MoSe2 is Bi 0.5 Na 0.5 TiO3 mass of 3-7 %.

2. The production method according to claim 1, characterized by, The mass of MoSe2 is Bi 0.5 Na 0.5 TiO3 5-7 %.

3. The preparation method according to claim 1, characterized in that, The specific preparation steps of the MoSe2 are as follows: NaBH4, Se powder, Na2MoO4 are mixed in a mass ratio of (0.2-0.6):(0.2-0.6):(0.3-0.7), stirred for 15-20 min to form a uniform suspension; the suspension is transferred to a polytetrafluoroethylene-lined autoclave and heated in a 200-240 ℃ oven for 15-20 h, cooled to room temperature, washed, dried, and MoSe2 is obtained.

4. The method of claim 1, wherein, The Bi 0.5 Na 0.5 The specific preparation steps of Bi2Ti2O7are as follows: BiCl3and TiO2are added into NaOH solution, and are magnetically stirred for 2-4 h to form a uniform suspension; the suspension is transferred into a polytetrafluoroethylene-lined autoclave, and is heated in an oven at 180-220 ℃ for 40-50 h, and is naturally cooled to room temperature, and then is washed and dried to obtain Bi2Ti2O7. 0.5 Na 0.5 TiO3.

5. The preparation method according to claim 4, characterized in that, The mass ratio of BiCl3 and TiO2 is (2-3):(1-2). And / or, the concentration of the NaOH solution is 14-16 mol / L.

6. The method of claim 1, wherein, The concentration of the ethanol solution is 90-99.9 wt%.

7. The preparation method according to claim 1, characterized in that, The ultrasonic power is 240 W, and the ultrasonic time is 30 min. And / or, the stirring speed is 400 r / min, and the stirring time is 24 h.

8. Bi prepared according to the method of any one of claims 1 to 7 0.5 Na 0.5 application of the TiO3 / MoSe2 composite catalyst, characterized in that, comprising the step of adding Bi 0.5 Na 0.5 TiO3 / MoSe2 composite catalyst is added to deionized water, ultrasonic dispersion, then add methanol, N2, under the condition of ultrasonic and light, sealed production of H2.

9. Use according to claim 8, characterized in that, The ultrasonic power is 240 W. And / or, the light is 55 W xenon lamp simulated sunlight. And / or, the volume ratio of methanol and deionized water is 1:9.

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