SV-ZIS prepared through rapid Joule thermal method and application of SV-ZIS to photocatalytic production of hydrogen peroxide from pure water

Abstract

The invention belongs to the field of preparation of photocatalysts, and particularly relates to an SV-ZIS prepared by a rapid Joule thermal method and application of the SV-ZIS to photocatalysis of pure water to generate hydrogen peroxide. The catalyst takes a ZnIn2S4 (ZIS) nanosheet as a material core, the catalyst is heated through a Joule heat device so as to regulate and control the form and performance of the catalyst, SV-ZIS with sulfur vacancies is synthesized, and the photocatalytic performance of the ZIS photocatalyst is improved. The photocatalyst is used for photocatalysis of pure water to generate hydrogen peroxide, and compared with a blank ZIS catalyst which is not subjected to Joule heat treatment, the photocatalyst has high catalytic activity.

Description

Technical Field

[0001] The present invention belongs to the field of preparation of photocatalysts, and specifically relates to a S V -Preparation method of ZIS photocatalyst. Background Art

[0002] As a resource-rich and environmentally friendly renewable energy source, solar energy can be used to decompose water through photocatalysis, convert it into chemical energy, and achieve efficient energy storage. Hydrogen peroxide (H2O2) is a widely used chemical with extensive applications in disinfection, chemical industry, and environmental remediation. The most advanced technology for industrial production of H2O2 is anthraquinone oxidation, which includes complex steps such as anthraquinone hydrogenation, oxidation, extraction, and purification. The traditional anthraquinone oxidation method for producing H2O2 inevitably brings environmental problems due to its high energy consumption and the generation of hazardous organic waste. In the past few decades, a lot of research has been conducted on the direct synthesis of H2O2 from H2 and O2 under precious metal catalysts (such as palladium and gold). However, the current shortcomings of H2O2 selectivity and low yield have severely limited the efficient process of direct synthesis of H2O2. Therefore, there is an urgent need for an environmentally friendly and safe process for producing H2O2.

[0003] Photosynthesis of H2O and O2 is considered to be an environmentally friendly strategy to replace the traditional H2O2 production pathway. It only requires abundant water and oxygen on Earth as raw materials and uses renewable sunlight as energy supply. Compared with the traditional anthraquinone oxidation method to produce H2O2, photocatalytic water production of hydrogen peroxide is of great significance. Sv (sulfur vacancies) in the photocatalyst ZIS can prolong the life of the photogenerated carrier and inhibit its recombination, thereby initiating O2 reduction and H2O oxidation to H2O2 through free radicals. The formation of Sv can strongly change the coordination structure of ZIS, regulate its adsorption capacity for intermediates, avoid excessive oxidation of H2O to O2 during the O2 / H2O redox process, and synergistically promote O2 reduction and H2O oxidation, thereby obtaining an ultra-high H2O2 yield. At present, there is no simple and rapid method to promote the generation of sulfur vacancies in the catalyst ZIS. Most methods require high temperature and long-term heating, and the subsequent treatment is more troublesome. Therefore, the development of a simple and efficient heating treatment method still needs to be explored. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a S-type product which has been subjected to Joule heat treatment in view of the shortcomings of the above-mentioned prior art. V -ZIS photocatalyst preparation method. The catalyst uses ZIS nanosheets as the material core, and the catalyst is heated by a Joule heat device to regulate its morphology and performance, synthesizing S with sulfur vacancies V -ZIS, improved S V-Photocatalytic performance of ZIS photocatalyst. The photocatalyst is used for photocatalytic production of hydrogen peroxide from water, and has high catalytic activity compared to blank ZIS catalyst that has not been subjected to Joule heat treatment. The technical solution adopted by the present invention to solve the above-mentioned problems is:

[0005] A S prepared by rapid Joule heating method V -The preparation method of ZIS photocatalyst, the specific steps are as follows:

[0006] (1) using zinc acetate, indium chloride, and thioacetamide as raw materials and water as solvent, mixing them evenly and then heating them under reflux for reaction, and the solid product obtained by the reaction is ZIS nanosheets;

[0007] (2) washing, drying and grinding the ZIS nanosheets obtained in step (1) to obtain a ZIS photocatalyst;

[0008] (3) The ZIS photocatalyst obtained in step (2) is placed in a mold of a Joule heat device, and subjected to heating treatment to obtain a S having sulfur vacancies. V -ZIS photocatalyst.

[0009] According to the above scheme, in step (1), the concentration ranges of zinc acetate, indium chloride and thioacetamide in water are 0.003-0.006 mol / L, 0.006-0.01 mol / L and 0.012-0.02 mol / L respectively, the volume range of solvent water is 90-110 mL, the temperature range of reflux heating reaction is 90-100° C., and the time range is 4-6 h.

[0010] According to the above scheme, in step (3), the ZIS photocatalyst is placed in a mold of a Joule heat device, and the mass range of the ZIS photocatalyst is 50-100 mg.

[0011] According to the above scheme, in step (3), the voltage range added to both ends of the Joule heat device is 1-3V, and the current range added to both ends of the device is 25-45A.

[0012] According to the above scheme, in step (3), the time range of heating the catalyst in the mold by the Joule heat device is 30-60s.

[0013] The S prepared by the above method V -ZIS photocatalyst can be used in the photocatalytic water-to-hydrogen peroxide reaction. The specific application method is: air is bubbled into the water for 10-15 minutes, and visible light is irradiated in an open system air atmosphere to achieve photocatalytic water-to-hydrogen peroxide production; the visible light wavelength is greater than or equal to 420nm, and the irradiation time is within 2h; the volume of water is preferably 10-15mL, and the concentration of the photocatalyst in water is preferably 1-3mg / mL.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention is in this S V -ZIS photocatalyst preparation, after Joule heat treatment, can quickly promote the formation of sulfur vacancies in the catalyst ZIS, so that ZIS has abundant sulfur vacancies, and after the power is turned off, the heat is quickly removed. Most operations require high temperature and long-term heating, and subsequent processing is more troublesome. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Comparison of blank ZIS catalyst and S with sulfur vacancies after Joule heating at different current and voltage V -Comparison of the catalytic activity of ZIS in the photocatalytic water-to-hydrogen peroxide reaction.

[0017] Figure 2 It is a diagram of a simple Joule heat heating device. DETAILED DESCRIPTION

[0018] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the present invention is not limited to the following embodiments.

[0019] Comparative Example

[0020] A method for preparing a ZIS photocatalyst, the specific steps are as follows:

[0021] 0.6mmol zinc acetate dihydrate Zn(CH3COO)2·2H2O, 1.2mmol indium chloride tetrahydrate (InCl3·4H2O) and 3.6mmol thioacetamide (C2H5NS) were dissolved in 100mL water and stirred for 30min. After stirring evenly, the mixture was transferred to a 100mL round-bottom flask and heated under reflux at 95°C for 5h. The mixture was then centrifuged at 8000rpm, washed with deionized water five times, and dried in vacuum at 60°C for 12h to obtain ZIS nanosheets, which were then ground to obtain ZIS photocatalysts.

[0022] The above catalyst is used in the photocatalytic water-to-hydrogen peroxide reaction, and the specific application process is as follows:

[0023] 10 mL of water and 10 mg of ZIS catalyst were placed in a hydrogen evolution tube, ultrasonicated for 15 min, and air bubbled in for 15 min. After the air was passed through, the reaction tube was irradiated with visible light (λ ≥ 420 nm) for 1 h in an open system. 1 mL of the liquid in the reaction tube was centrifuged every 15 min, and the supernatant after centrifugation was taken to evaluate the photocatalytic H2O2 concentration on a UV-visible spectrophotometer by iodine titration.

[0024] Example 1

[0025] A S V -The preparation method of ZIS photocatalyst (1.8V 35A), the specific steps are as follows:

[0026] The blank catalyst in the comparative example was placed in a mold of a Joule heating device, the power supply voltage and current were adjusted to 1.8V 35A, and heated for 60s. After Joule heating treatment, S V -ZIS photocatalyst.

[0027] The above S V -ZIS catalyst is used in the photocatalytic water-to-hydrogen peroxide reaction. The specific application process is as follows:

[0028] Take 10mL water, 10mg S V -ZIS catalyst was placed in a hydrogen evolution tube, mixed evenly after ultrasonic treatment for 15 minutes, and air was bubbled in for 15 minutes. After the air was passed, the reaction tube was irradiated with visible light (λ≥420nm) for 1 hour in an open system; 1 mL of the liquid in the reaction tube was centrifuged every 15 minutes, and the supernatant after centrifugation was taken to evaluate the H2O2 concentration on a UV-visible spectrophotometer by iodine titration.

[0029] Example 2

[0030] A S V -The preparation method of ZIS photocatalyst (1.8V 40A), the specific steps are as follows:

[0031] The blank catalyst in the comparative example was placed in a mold of a Joule heating device, the power supply voltage and current were adjusted to 1.8V40A, and heated for 60s. After Joule heating treatment, S V -ZIS photocatalyst.

[0032] The above S V -ZIS catalyst is used in the photocatalytic water-to-hydrogen peroxide reaction. The specific application process is as follows:

[0033] Take 10mL water, 10mg S V -ZIS catalyst was placed in a hydrogen evolution tube, mixed evenly after ultrasonic treatment for 15 minutes, and air was bubbled in for 15 minutes. After the air was passed, the reaction tube was irradiated with visible light (λ≥420nm) for 1 hour in an open system; 1 mL of the liquid in the reaction tube was centrifuged every 15 minutes, and the supernatant after centrifugation was taken to evaluate the H2O2 concentration on a UV-visible spectrophotometer by iodine titration.

[0034] like Figure 1 As shown, after Joule heat treatment, S V-ZIS has higher catalytic activity in the photocatalytic water-to-hydrogen peroxide reaction. The Joule heat promotes the generation of abundant sulfur vacancies in ZIS, and after about 1 hour of light irradiation, the sulfur vacancies in S V -ZIS catalyzed the H2O2 concentration to a maximum of 300 μmol g -1 About 10 times the activity of blank ZIS.

[0035] like Figure 2 Shown is the before and after change diagram of the ZIS catalyst after Joule heat treatment under different parameters.

[0036] The above is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and changes without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A S prepared by rapid Joule heating method V -The preparation method of ZIS photocatalyst, the specific steps are as follows: (1) using zinc acetate, indium chloride, and thioacetamide as raw materials and water as solvent, mixing them evenly and then heating them under reflux for reaction, and the solid product obtained by the reaction is ZIS nanosheets; (2) washing, drying and grinding the ZIS nanosheets obtained in step (1) to obtain a ZIS photocatalyst; (3) placing the ZIS photocatalyst obtained in step (2) into a mold of a Joule heat device, and subjecting it to Joule heat treatment to obtain S with sulfur vacancies V -ZIS photocatalyst.

2. The Joule heat treated S according to claim 1. V -A method for preparing a ZIS photocatalyst, characterized in that: In step (3), the ZIS photocatalyst is placed in a Joule heat device, and the mass range of the ZIS photocatalyst is 50-100 mg.

3. The Joule heat treated S according to claim 1. V -A method for preparing a ZIS photocatalyst, characterized in that: In step (3), the voltage range attached to both ends of the Joule heat device is 1-3V, and the current range attached to both ends of the device is 25-45A.

4. The Joule heat treated S according to claim 1. V -A method for preparing a ZIS photocatalyst, characterized in that: In step (3), the catalyst in the mold is heated by a Joule heat device for a time range of 30-60 seconds.

5. The Joule heat treated S according to claim 1 V -A method for preparing a ZIS photocatalyst, characterized in that: In step (1), the molar ratio of zinc acetate, indium chloride and thioacetamide is 1:2:(4-6), the concentration ranges of zinc acetate, indium chloride and thioacetamide in water are 0.003-0.006 mol / L, 0.006-0.01 mol / L and 0.012-0.02 mol / L respectively, the volume range of solvent water is 90-110 mL, the temperature range of reflux heating reaction is 90-100° C., and the time range is 4-6 h.

6. The Joule heat treated S according to claim 1. V -A method for preparing a ZIS photocatalyst, characterized in that: In step (2), washing is performed with deionized water, and drying is performed in a vacuum oven.

7. The method according to any one of claims 1 to 6 for preparing S after Joule heat treatment V -ZIS photocatalyst.

8. The Joule heat treated S according to claim 7. V -Application of ZIS photocatalyst in photocatalytic production of hydrogen peroxide from water.

9. The use according to claim 8, characterized in that The specific application method is: S V -ZIS photocatalyst is added into water, ultrasonically dispersed or stirred evenly, then air is introduced and visible light irradiation is performed in an open system air atmosphere to achieve photocatalytic water production of hydrogen peroxide; wherein, the wavelength of visible light is not less than 420nm, and the irradiation time does not exceed 2h.

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