Sn3O4 / Mn 0.5 Cd 0.5 S composite catalyst, its preparation method, and its application in piezoelectric photocatalytic H2 production.

Abstract

The application belongs to the field of piezoelectric photocatalysis, and particularly relates to a Sn3O4 / Mn 0.5 Cd 0.5 S composite catalyst, a preparation method thereof and piezoelectric photocatalytic H2 production application. 0.5 Cd 0.5 S nanoparticles and nanoflower Sn3O4 are prepared by a hydrothermal synthesis method, and finally, the two are combined to form a heterojunction by a simple ultrasonic stirring method to prepare the Sn3O4 / Mn 0.5 Cd 0.5 S composite catalyst. The catalyst is used for piezoelectric photocatalytic H2 production under the synergistic action of sunlight irradiation and ultrasonic vibration. The catalyst synthesis method is simple, green, pollution-free and operable. The prepared catalyst has abundant active sites, a larger specific surface area and excellent hydrogen production effect.

Description

Technical Field

[0001] This invention belongs to the field of piezoelectric photocatalysis, specifically relating to a Sn3O4 / Mn 0.5 Cd 0.5 S composite catalyst, its preparation method, and its application in piezoelectric photocatalytic H2 production. Background Technology

[0002] Elemental doping, piezoelectric effect, and heterostructure are important methods for improving photocatalysis. Cadmium sulfide (CdS) is a typical group II-VI n-type direct bandgap semiconductor material and has been widely used in photocatalytic degradation and photocatalytic water splitting for hydrogen production. However, CdS has a significant drawback: excessive charge carriers in CdS are prone to photocorrosion. The h generated in the CdS valence band... + Easy and S 2- A reaction occurs, causing Cd 2+ Dissolving in solution causes secondary pollution. Mn is formed by doping CdS with metallic Mn. x Cd 1-x S solid solutions can improve h + With e - The separation efficiency is reduced by h. + With S 2- The reaction is more efficient, and the photocatalytic performance is far superior to that of CdS. For example, patent CN110252359A discloses a method for preparing a cadmium sulfide heterojunction photocatalyst for water splitting to produce hydrogen, which enhances the separation and transport efficiency of photogenerated carriers. However, the above-mentioned catalyst preparation method is cumbersome, complex, and difficult to operate. Summary of the Invention

[0003] The purpose of this invention is to provide a Sn3O4 / Mn 0.5 Cd 0.5 The S composite catalyst was applied to piezoelectric photocatalytic hydrogen production, and the resulting catalyst exhibited higher catalytic performance and stronger corrosion resistance.

[0004] The Sn3O4 / Mn provided by this invention 0.5 Cd 0.5 The preparation method of the S composite catalyst includes the following steps:

[0005] (1)Mn 0.5 Cd 0.5 Preparation of S:

[0006] Mn(CH3COO)2·4H2O and Cd(CH3COO)2·2H2O were dissolved in distilled water and stirred for 30 min until fully dissolved. Then, C2H5NS(TAA) was added, and stirring continued until homogeneous. The mixture was then transferred to a reaction vessel lined with polytetrafluoroethylene (PTFE). The reaction vessel was placed in an oven at 160°C for 24 h, then cooled to room temperature. After filtration, the solid was washed three times with deionized water and anhydrous ethanol, and dried overnight at 60°C to obtain orange Mn. 0.5 Cd 0.5 S (abbreviated as: MCS).

[0007] The molar ratio of Mn(CH3COO)2·4H2O to Cd(CH3COO)2·2H2O is 1:1; the mass ratio of C2H5NS to Mn(CH3COO)2·4H2O is 0.7513:1.2254.

[0008] (2) Preparation of Sn3O4

[0009] SnCl2·2H2O and Na3C6H5O7·2H2O were dispersed in H2O and stirred for 20 min to ensure uniform dispersion. Then, 12.5 mL of 0.2 mol / L NaOH solution was added and stirred for 20 min to ensure uniform mixing. The mixture was then transferred to a reaction vessel with a polytetrafluoroethylene liner and placed in an oven at 180 °C for 12 h. After the reaction was complete, the mixture was cooled to room temperature, and the solid in the reaction vessel was washed and dried to obtain Sn3O4.

[0010] The molar ratio of SnCl2·2H2O and Na3C6H5O7·2H2O is 1:2.5; the mass ratio of SnCl2·2H2O and NaOH is 1.1283:0.1.

[0011] (3) Sn3O4 / Mn 0.5 Cd 0.5 Preparation of S composite catalyst:

[0012] Mn 0.5 Cd 0.5 The S catalyst and Sn3O4 catalyst were dissolved in a solvent and subjected to ultrasonication and stirring. After filtration, washing, and drying at room temperature, an orange powder was finally obtained, which is the Sn3O4 / Mn catalyst. 0.5 Cd 0.5 S composite catalyst.

[0013] The solvent is: deionized water, anhydrous ethanol, or a mixture of anhydrous ethanol and water; the amount of Sn3O4 added is Mn 0.5 Cd 0.5 S content is 5% to 9% of the mass.

[0014] The ultrasonic power was 240W, the ultrasonic time was 1 hour, the stirring speed was 400r / min, and the stirring time was 4 hours.

[0015] The composite catalyst prepared above is used for piezoelectric photocatalytic hydrogen production. The specific application method is as follows: Weigh Sn3O4 / Mn... 0.5 Cd 0.5 The S composite catalyst is added to water and ultrasonically dispersed. Then, Na2S and Na2SO3 aqueous solutions are added as sacrificial agents, and N2 is passed through. H2 is produced in a sealed environment under the combined conditions of ultrasound and light irradiation.

[0016] The ultrasonic power is 240W, and the light power is 55W.

[0017] The concentrations of Na2S and Na2SO3 in the sacrificial agent solution were 0.35M and 0.25M, respectively.

[0018] Sn3O4 / Mn 0.5 Cd 0.5 The dosage of the S composite catalyst in water is 2 mg / 18 mL.

[0019] The advantages of this invention are:

[0020] (1) This invention synthesizes Sn3O4 / Mn 0.5 Cd 0.5 The method for synthesizing Sn3O4 / Mn composite catalysts is simple and easy to operate. 0.5 Cd 0.5 The S composite catalyst has a larger specific surface area, which is one of the reasons for the improved piezoelectric photocatalytic performance.

[0021] (2) The introduction of Sn3O4 did not change Mn 0.5 Cd 0.5 The crystal structure of S indicates that Sn3O4 is deposited only on Mn 0.5 Cd 0.5 The surface of S indicates Sn3O4 / Mn 0.5 Cd 0.5 The S composite catalyst exhibits good crystallinity.

[0022] (3) Sn3O4 / Mn synthesized in this invention 0.5 Cd 0.5 The S composite catalyst has a lower overpotential and lower resistance, which is more conducive to hydrogen evolution and electron transport. Attached image description:

[0023] Figure 1 Mn synthesized by hydrothermal synthesis 0.5 Cd 0.5 XRD patterns of S and Sn3O4.

[0024] Figure 2 X% Sn3O4 / Mn was synthesized by impregnation method. 0.5 Cd 0.5 XRD pattern of S (where X is the proportion of Sn3O4) composite catalyst.

[0025] Figure 3 It is Mn 0.5 Cd 0.5 S, Sn3O4 and 7% Sn3O4 / Mn 0.5 Cd 0.5 SEM and EDS images of the S composite catalyst.

[0026] Figure 4 It is Mn 0.5 Cd 0.5 S and 7% Sn3O4 / Mn 0.5 Cd 0.5 LSV curve of S composite catalyst.

[0027] Figure 5 It is Mn 0.5 Cd 0.5 S and 7% Sn3O4 / Mn 0.5 Cd 0.5 EIS diagram of the S composite catalyst. Detailed Implementation

[0028] This invention is not limited to the following specific embodiments. Those skilled in the art can implement this invention using various other specific embodiments based on the content disclosed herein. Any modifications or alterations to the design structure and concept of this invention fall within the protection scope of this invention. It should be noted that, in the absence of conflict, the embodiments and features described in these embodiments can be combined with each other. The H2 production efficiency is calculated using the following formula:

[0029]

[0030] R: H2 production rate, unit: μmol / (g·h), V: hydrogen volume, unit: μL, m: catalyst mass, unit: g, t: reaction time, unit: h.

[0031] Example 1

[0032] 5 mmol of Mn(CH3COO)2·4H2O and 5 mmol of Cd(CH3COO)2·2H2O were dissolved in distilled water and stirred for 30 min until fully dissolved. Then, 10 mmol of thioacetamide (TAA) was added and stirred until homogeneous. The mixture was then transferred to a polytetrafluoroethylene-lined reactor and placed in an oven at 160 °C for 24 h. After the reaction was completed, the mixture was cooled to room temperature. The solid in the reactor was washed three times with deionized water and anhydrous ethanol and dried overnight at 60 °C to obtain orange Mn. 0.5 Cd 0.5 S powder.

[0033] 5 mmol SnCl2·2H2O and 12.5 mmol Na3C6H5O7·2H2O were dispersed in 12.5 mL of H2O and stirred for 20 min to ensure uniform dispersion. Then, 12.5 mL of 0.2 mol / L NaOH solution was added and stirred for 20 min to ensure uniform mixing. The mixture was then transferred to a reaction vessel with a polytetrafluoroethylene liner and placed in an oven at 180 °C for 12 h. After the reaction was complete, the mixture was cooled to room temperature, and the solid in the reaction vessel was washed and dried to obtain Sn3O4.

[0034] The above Mn 0.5 Cd 0.5 The S catalyst and Sn3O4 catalyst were dissolved in 10 mL of deionized water and subjected to ultrasonication at 240 W for 1 h followed by stirring at 400 r / min for 4 h. The mixture was then filtered, washed, and dried at room temperature to obtain an orange powder, which is the Sn3O4 / Mn catalyst. 0.5 Cd 0.5 S composite catalyst. The mass of Sn3O4 is equal to that of Mn. 0.5 Cd 0.5 7% of the S quality.

[0035] Table 1

[0036]

[0037] 7% Sn3O4 / Mn 0.5 Cd 0.5 Application methods of S composite catalysts:

[0038] Weigh out 2 mg of 7% Sn3O4 / Mn 0.5 Cd 0.5The S composite catalyst was added to 18 mL of water and ultrasonically dispersed for half an hour to ensure uniform dispersion. Then, a mixed solution of 0.35 M Na₂S and 0.25 M Na₂SO₃ was added as a sacrificial agent, followed by N₂ purging for half an hour. Finally, the mixture was sealed for 2 hours 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 21.46 mmol / (g·h).

[0039] Example 2

[0040] The difference compared to Example 1 is that the mass of Sn3O4 added during the preparation process is Mn 0.5 Cd 0.5 S is 5% of the mass, and other preparation methods are the same as in Example 1.

[0041] The application method is the same as in Example 1 and Example 2 for the preparation of 5% Sn3O4-Mn. 0.5 Cd 0.5 The S composite catalyst produced H2 at a rate of 14.77 mmol / (g·h).

[0042] Example 3

[0043] The difference compared to Example 1 is that the mass of Sn3O4 added during the preparation process is Mn 0.5 Cd 0.5 The mass of S is 6%, and the other preparation methods are the same as in Example 1.

[0044] The application method is the same as in Example 1 and Example 3 for the 6% Sn3O4 / Mn. 0.5 Cd 0.5 The S composite catalyst produced H2 at a rate of 18.06 mmol / (g·h).

[0045] Example 4

[0046] The difference compared to Example 1 is that the mass of Sn3O4 added during the preparation process is Mn 0.5 Cd 0.5 The mass of S is 8%, and the other preparation methods are the same as in Example 1.

[0047] The application method is the same as in Example 1 and Example 4 for the 8% Sn3O4 / Mn. 0.5 Cd 0.5 The S composite catalyst produced H2 at a rate of 16.11 mmol / (g·h).

[0048] Example 5

[0049] The difference compared to Example 1 is that the mass of Sn3O4 added during the preparation process is Mn 0.5 Cd 0.5 S is 9% of the mass, and other preparation methods are the same as in Example 1.

[0050] The application method is the same as in Example 1 and Example 5 for the preparation of 9% Sn3O4 / Mn. 0.5 Cd 0.5 The S composite catalyst produced H2 at a rate of 11.79 mmol / (g·h).

[0051] Example 6

[0052] The difference compared to Example 1 is that Mn 0.5 Cd 0.5 S and Sn3O4 are dissolved in anhydrous ethanol, and the rest is the same as in Example 1.

[0053] The application method is the same as in Example 1 and Example 6 for the 7% Sn3O4 / Mn. 0.5 Cd 0.5 The S composite catalyst produced H2 at a rate of 20.63 mmol / (g·h).

[0054] Example 7

[0055] The difference compared to Example 1 is that Mn 0.5 Cd 0.5 S and Sn3O4 are dissolved in anhydrous ethanol and water in a mixed solution (volume ratio of 1:1), and the rest is the same as in Example 1.

[0056] The application method is the same as in Example 1 and Example 7 for the 7% Sn3O4 / Mn. 0.5 Cd 0.5 The S composite catalyst produced H2 at a rate of 17.42 mmol / (g·h).

[0057] Example 8

[0058] The difference compared to Example 1 is that Mn 0.5 Cd 0.5 S and Sn3O4 are dissolved in anhydrous ethanol and water in a mixed solution (volume ratio of 2:3), and the rest is the same as in Example 1.

[0059] The application method is the same as in Example 1 and Example 8, which prepared 7% Sn3O4 / Mn. 0.5 Cd 0.5 The S composite catalyst produced H2 at a rate of 18.47 mmol / (g·h).

[0060] Example 9

[0061] The difference compared to Example 1 is that Mn 0.5 Cd0.5 S and Sn3O4 are dissolved in anhydrous ethanol and water in a mixed solution (volume ratio of 3:2), and the rest is the same as in Example 1.

[0062] The application method is the same as in Example 1 and Example 9, which prepared 7% Sn3O4 / Mn. 0.5 Cd 0.5 The S composite catalyst produced H2 at a rate of 15.62 mmol / (g·h).

[0063] Comparative Example 1

[0064] Compared to Example 1, the difference is that the ultrasonic (240W) and light (55W xenon lamp simulating sunlight) application methods were changed to ultrasonic only (240W), otherwise the same as Example 1. 7% Sn3O4 / Mn 0.5 Cd 0.5 The S catalyst produces H2 at a rate of 109.95 μmol / (g·h).

[0065] Comparative Example 2

[0066] Compared to Example 1, the difference is that the application method was changed from ultrasonic (240W) and light irradiation (55W xenon lamp simulating sunlight) to light irradiation only (55W xenon lamp simulating sunlight), otherwise the same as Example 1. 7% Sn3O4 / Mn 0.5 Cd 0.5 The S catalyst produces H2 at a rate of 6.65 mmol / (g·h).

[0067] Comparative Example 3

[0068] Compared with Example 1, the difference is that the molar ratio of Mn(CH3COO)2·4H2O and Cd(CH3COO)2·2H2O added is 0.4:0.6, and the prepared composite catalyst is designated as 7%Sn3O4 / Mn. 0.3 Cd 0.7 S.

[0069] The application method is the same as in Example 1, and the prepared 7% Sn3O4 / Mn 0.4 Cd 0.6 The S composite catalyst produces H2 at a rate of 426.33 μmol / (g·h).

[0070] Comparative Example 4

[0071] Compared with Example 1, the difference is that the molar ratio of Mn(CH3COO)2·4H2O and Cd(CH3COO)2·2H2O added is 0.6:0.4, and the prepared composite catalyst is designated as 7%Sn3O4 / Mn. 0.6 Cd 0.4 S.

[0072] The application method is the same as in Example 1, and the prepared 7% Sn3O4 / Mn 0.6 Cd 0.4 The hydrogen production rate of the S composite catalyst is 2006.43 μmol / (g·h).

[0073] Comparative Example 5

[0074] 0.0871 g of Sn3O4 was added to 40 mL of H2O and stirred for 2 h to dissolve completely. Then, 1.2254 g of Mn(CH3COO)2·4H2O and 1.3326 g of Cd(CH3COO)2·2H2O were added and stirred for 30 min. Finally, 0.7513 g of thioacetamide was added and stirred for 30 min to obtain a homogeneous solution. The mixture was then transferred to a polytetrafluoroethylene-lined reactor and placed in an oven at 160 °C for 24 h. After the reaction was completed, the mixture was cooled to room temperature. The solid in the reactor was washed three times with deionized water and anhydrous ethanol and dried overnight at 60 °C to obtain the hydrothermal composite 7% Sn3O4 / Mn 0.5 Cd 0.5 S catalyst.

[0075] The application method is the same as in Example 1, using hydrothermal synthesis of 7% Sn3O4 / Mn. 0.5 Cd 0.5 The hydrogen production rate of the S composite catalyst is 2.13 mmol / (g·h).

[0076] Comparative Example 6

[0077] Dissolve 0.205 g of SnCl2·2H2O in a mixed solution of ethanol and water (volume ratio 3:2), stir for 20 min, then add 7 mL of NH3·H2O as a mineralizing agent, stir for 1 h, and finally transfer the mixture to a reaction vessel lined with polytetrafluoroethylene. Place the reaction vessel in an oven at 120 °C for 6 h. After the reaction is complete, cool to room temperature, wash the solid in the reaction vessel three times with deionized water and anhydrous ethanol, and dry at 60 °C overnight to obtain SnO2.

[0078] The above Mn 0.5 Cd 0.5 The S catalyst and SnO2 catalyst were dissolved in 10 mL of deionized water and subjected to ultrasonication at 240 W for 1 h followed by stirring at 400 r / min for 4 h. The mixture was then filtered, washed, and dried at room temperature to obtain an orange powder, which is the SnO2 / Mn catalyst. 0.5 Cd 0.5 S composite catalyst. Wherein, the mass of SnO2 is Mn 0.5 Cd 0.5 7% of the S quality.

[0079] The application method is the same as in Example 1, and the resulting 7% SnO2 / Mn 0.5 Cd 0.5 The hydrogen production rate of the S composite catalyst is 4.51 mmol / (g·h).

Claims

1. A Sn3O4 / Mn 0.5 Cd 0.5 The S composite catalyst, characterized in that, The composite catalyst is made of Mn 0.5 Cd 0.5 The heterojunction structure formed by the combination of S and Sn3O4, Sn3O4 is Mn 0.5 Cd 0.5 S quality 5-9%; The Sn3O4 / Mn 0.5 Cd 0.5 The preparation method of S composite catalyst is as follows: Mn 0.5 Cd 0.5 S and Sn3O4 are dissolved in a solvent, and after sonication and stirring, the mixture is filtered, washed, and dried to obtain Sn3O4 / Mn. 0.5 Cd 0.5 S composite catalyst.

2. The Sn3O4 / Mn according to claim 1 0.5 Cd 0.5 The S composite catalyst, characterized in that, The preparation method of Sn3O4 is as follows: SnCl2·2H2O and Na3C6H5O7·2H2O are dispersed in H2O and stirred until uniform. Then, NaOH solution is added and stirred until uniform. The mixture is then transferred to a reaction vessel with a polytetrafluoroethylene liner and placed in an oven to stand. After the reaction is completed, it is cooled to room temperature. The solid in the reaction vessel is washed and dried to obtain Sn3O4.

3. The Sn3O4 / Mn according to claim 2 0.5 Cd 0.5 The S composite catalyst, characterized in that, The mass ratio of SnCl2·2H2O, Na3C6H5O7·2H2O, and NaOH is 1.1283:3.6763:0.1; the reaction temperature is 180 ℃, and the reaction time is 12 h.

4. The Sn3O4 / Mn according to claim 1 0.5 Cd 0.5 The S composite catalyst, characterized in that, The Mn 0.5 Cd 0.5 The preparation method of S is as follows: Mn(CH3COO)2·4H2O and Cd(CH3COO)2·2H2O are dissolved in deionized water and stirred. Then, C2H5NS is added and stirred until the mixture is homogeneous. The mixture is then transferred to a reaction vessel with a polytetrafluoroethylene liner and placed in an oven. After the reaction is completed, it is cooled to room temperature. The solid in the reaction vessel is washed and dried to obtain orange Mn. 0.5 Cd 0.5 S.

5. The Sn3O4 / Mn according to claim 4 0.5 Cd 0.5 The S composite catalyst, characterized in that, The molar ratio of Mn(CH3COO)2·4H2O and Cd(CH3COO)2·2H2O is 1:1, and the mass ratio of C2H5NS to Mn(CH3COO)2·4H2O is 0.7513:1.2254; the reaction temperature is 160℃, and the reaction time is 24 h.

6. The Sn3O4 / Mn according to claim 1 0.5 Cd 0.5 The S composite catalyst, characterized in that, In the preparation of the composite catalyst, the solvent is deionized water, anhydrous ethanol, or a mixture of deionized water and anhydrous ethanol; the ultrasonic power is 240 W, and the ultrasonic time is 1 h; the stirring speed is 400 r / min, and the stirring time is 4 h.

7. A Sn3O4 / Mn according to any one of claims 1-5 0.5 Cd 0.5 The application of S composite catalyst is characterized by... The catalyst is used for piezoelectric photocatalytic H2 production.

8. The Sn3O4 / Mn according to claim 7 0.5 Cd 0.5 The application of S composite catalyst is characterized by... The method for using the catalyst in piezoelectric photocatalytic H2 production is as follows: Sn3O4 / Mn 0.5 Cd 0.5 The S composite catalyst was added to water and dispersed evenly. Then, a sacrificial agent was added, and then N2 was passed through it to produce H2 under ultrasonic and light conditions.

9. The Sn3O4 / Mn according to claim 8 0.5 Cd 0.5 The application of S composite catalyst is characterized by... The sacrificial agent solution contains Na2S and Na2SO3 at concentrations of 0.35 M and 0.25 M, respectively, with an ultrasonic power of 240 W and sunlight simulated by a 55 W xenon lamp.

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