ZnCo2O4 / Co rich in sulfur vacancies 0.2 Cd 0.8 S-Vs composite catalyst and use thereof

Abstract

The application belongs to the field of piezoelectric photocatalysts, and particularly relates to a ZnCo2O4 / Co 0.2 Cd 0.8 S-Vs composite catalyst and application thereof. Co 0.2 Cd 0.8 S is prepared through a hydrothermal synthesis method, Co 0.2 Cd 0.8 S-Vs with sulfur vacancies is prepared through NaOH etching, and then a ZnCo2O4 / Co 0.2 Cd 0.8 S-Vs composite catalyst is prepared through a simple impregnation method with cobalt zinc oxide as a cocatalyst, and piezoelectric photocatalytic H2 or H2O2 is generated under the synergistic action of sunlight irradiation and ultrasonic vibration. The application has the advantages of simple synthesis method, greenness, no pollution, simple operation, rich active sites, excellent stability, no secondary pollution and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of piezoelectric photocatalysts, and particularly relates to a ZnCo2O4 / Co

[0002] / Co 0.2 Cd 0.8 S-Vs composite catalyst and application thereof. BACKGROUND

[0003] Hydrogen energy is a kind of green energy with zero pollution and high heat value. The concept of producing hydrogen by splitting water using solar energy is considered by many researchers as the ultimate solution to the energy crisis in the future. Semiconductor catalysts are an important part of the process of photocatalytic water splitting. So far, many photocatalytic materials, such as CdS, have been deeply studied as potential catalysts for H2 evolution.

[0004] For example, patent CN109876827A discloses a double-Z-type single-heterojunction CuO / WO3 / CdS photocatalyst and its preparation method and application. The prepared catalyst can inhibit the recombination of electrons and holes, efficiently utilize sunlight, and thus improve the catalytic activity of the photocatalyst. Patent CN117205945A discloses an alpha-NiS / CdS photocatalyst and its preparation method and application. It uses NiS to replace the traditional noble metal catalyst, reduces the production cost, and has higher catalytic activity and stability. However, the preparation methods of the above-mentioned catalysts are relatively complicated, and the hydrogen production efficiency of the final samples is not high. In addition, the photo-corrosion of CdS is mainly due to the rapid oxidation of the CdS surface lattice by light holes after visible light irradiation, which causes serious damage to the CdS surface, thereby seriously reducing the activity and hydrogen production rate of the CdS catalyst. SUMMARY

[0005] The purpose of the present application is to provide a ZnCo2O4 / Co 0.2 Cd 0.8 S-Vs composite catalyst rich in sulfur vacancies, and to apply it to piezoelectric photocatalytic H2 production and photocatalytic H2O2 production, which has high catalytic activity and good stability.

[0006] The ZnCo2O4 / Co 0.2 Cd 0.8 S-Vs composite catalyst rich in sulfur vacancies provided by the present application has the advantages that:

[0007] (1) Preparation of Co 0.2 Cd 0.8 S-Vs:

[0008] CoCl2-6H2O, Cd(CH3COO)2-2H2O were mixed in a molar ratio of 1:4-1:9, C2H5NS dissolved in distilled water was added, stirred for 1 h, then ethylenediamine was added and stirred for 1 h to make them mix uniformly, then the mixed solution was transferred into a reaction kettle with a polytetrafluoroethylene lining, and placed in an oven at 180°C for 12 h. After the reaction was completed, the solid in the reaction kettle was washed with deionized water and anhydrous ethanol three times each, and dried at 60°C overnight to obtain a yellow-green Co 0.2 Cd 0.8 S.

[0009] Co 0.2 Cd 0.8 S and NaOH were then dispersed in an aqueous solution, and ultrasonic treatment was performed to obtain sufficient gas bubbles to provide conditions (ultrasonic treatment time preferably 20 min) for obtaining Co 0.2 Cd 0.8 S-Vs. After the reaction was completed, the solid was separated at room temperature, washed and dried to obtain Co 0.2 Cd 0.8 S-Vs.

[0010] Further, the mass ratio of the C2H5NS to CoCl2-6H2O was 0.119:0.381.

[0011] (2) Preparation of ZnCo2O4:

[0012] Co(CH3COO)2-4H2O and Zn(CH3COO)2-2H2O were dispersed in distilled water and stirred to mix, CH4N2O and NH4F were then added and stirred to mix, and then the mixed solution was transferred into a reaction kettle lined with polytetrafluoroethylene. The reaction kettle was placed in an oven at 120°C for 6 h. After the reaction was completed, the solid in the reaction kettle was washed with deionized water and anhydrous ethanol three times each, and dried at 60°C overnight to obtain a powder purple ZnCo2O4 precursor. Finally, the precursor was placed in a tube furnace, heated to 400°C at a rate of 5°C / min, and calcined for 2 h to obtain black ZnCo2O4.

[0013] Further, the mass ratio of the Co(CH3COO)2-4H2O to Zn(CH3COO)2-2H2O was 0.22:0.498.

[0014] (3) Preparation of ZnCo2O4 / Co 0.2 Cd 0.8 S-Vs composite catalyst:

[0015] Co 0.2 Cd 0.8S-Vs catalyst and ZnCo2O4 catalyst are dissolved in a solvent and stirred. Filtration, washing and drying are carried out at room temperature, and finally, a yellow-green powder, namely ZnCo2O4 / Co 0.2 Cd 0.8 S-Vs composite catalyst.

[0016] The added mass of ZnCo2O4 is 1-7% of the mass of Co 0.2 Cd 0.8 S-Vs, preferably 3-5%.

[0017] The solvent includes deionized water and anhydrous ethanol.

[0018] The stirring speed is 400 r / min, and the time is 20 h.

[0019] The composite catalyst prepared by the above method is used for piezoelectric photocatalytic hydrogen production or photocatalytic H2O2 production.

[0020] The specific method for the catalyst to produce hydrogen by piezoelectric photocatalysis is that ZnCo2O4 / Co 0.2 Cd 0.8 S-Vs composite catalyst is uniformly dispersed in water, then a sacrificial agent is added, N2 is passed, and H2 is produced under the combined conditions of ultrasonic and light irradiation.

[0021] The sacrificial agent is lactic acid, the ultrasonic power is 240 W, and the light irradiation power is 55 W.

[0022] ZnCo2O4 / Co 0.2 Cd 0.8 The amount of ZnCo2O4 / Co

[0023] The specific method for the catalyst to produce H2O2 by piezoelectric photocatalysis is that ZnCo2O4 / Co 0.2 Cd 0.8 S-Vs composite catalyst is added to distilled water, dispersed sufficiently, and then reacted under ultrasonic and sunlight irradiation.

[0024] The ultrasonic power is 240 W, and the light irradiation power is 55 W.

[0025] ZnCo2O4 / Co 0.2 Cd 0.8 The amount of ZnCo2O4 / Co

[0026] The beneficial effects of the present application are:

[0027] (1) The present application synthesizes Co 0.2 Cd 0.8S-Vs, ZnCo2O4 / Co 0.2 Cd 0.8 S-Vs composite catalyst, which has the characteristics of simple synthesis conditions, easy operation, fast and efficient, energy saving and environmental protection.

[0028] (2) The introduction of the cocatalyst ZnCo2O4 does not change the Co 0.2 Cd 0.8 S-Vs crystal structure, ZnCo2O4 / Co 0.2 Cd 0.8 S-Vs composite catalyst has high crystallinity and purity.

[0029] (3) ZnCo2O4 / Co 0.2 Cd 0.8 S-Vs composite catalyst produces H2 or H2O2 under the combined action of photocatalysis, piezoelectric catalysis and piezoelectric light, and the catalytic performance under the combined action of piezoelectric light is the best, which is 3.35 times that of Co 0.2 Cd 0.8 S, and 11.51 times that of CdS. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is ZnCo2O4 / Co synthesized in Example 1 0.2 Cd 0.8 S-Vs composite catalyst is a scanning electron microscope image;

[0031] Figure 2 is Co 0.2 Cd 0.8 S, Co 0.2 Cd 0.8 S-Vs, ZnCo2O4 and CdS catalysts are XRD patterns;

[0032] Figure 3 is ZnCo2O4 / Co synthesized in Examples 1-4 0.2 Cd 0.8 S-Vs composite catalyst is an XRD pattern;

[0033] Figure 4 is a performance graph of H2 production of different catalysts under the action of piezoelectric light;

[0034] Figure 5 is a performance graph of H2 production of different catalysts under the action of piezoelectric light only;

[0035] Figure 6 is a performance graph of H2 production of different catalysts under the action of light only.

[0036] Figure 7Figure 2 shows the H2O2 production performance of the catalyst synthesized in Example 1-4 under piezoelectric light irradiation conditions;

[0037] Figure 8 The color change of the solution after two hours of CdS light irradiation can be seen to change from orange-red to yellow-green.

[0038] Figure 9 The color change of the solution after two hours of Co 0.2 Cd 0.8 S light irradiation is almost unchanged.

[0039] Figure 10 The color change of the solution after two hours of 3% ZnCo2O4 / Co 0.2 Cd 0.8 S-Vs light irradiation is almost unchanged. DETAILED DESCRIPTION

[0040] The present application is not limited to the following detailed description, and those skilled in the art can use other various embodiments to implement the present application according to the disclosure of the present application, or any simple changes or modifications made by using the design structure and ideas of the present application, all fall within the scope of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The H2 production efficiency is calculated according to the following formula:

[0041]

[0042] R: H2 production rate, unit: μmol / (g·h), V: hydrogen volume, unit: μL, m: catalyst mass, unit: g, t: reaction time, unit: h.

[0043] The formula for calculating the H2O2 production rate is:

[0044] Y = 0.004X + 0.0041

[0045]

[0046] Y: measured absorbance value, R: H2O2 production rate, unit: μmol / (g·h), V: solvent volume, unit: L, m: catalyst mass, unit: g, t: reaction time, unit: h.

[0047] Example 1

[0048] (1) 0.119 g CoCl2·6H2O, 0.533 g Cd(CH3COO)2·2H2O were mixed, then 0.381 g C2H5NS dissolved in distilled water was added, stirred for 1 h, 25 ml ethylenediamine was added and stirred for 1 h to make them mixed uniformly, then the mixture was transferred into a reaction kettle with polytetrafluoroethylene lining, placed in an oven at 180 °C for 12 h, after the reaction was completed, cooled to room temperature, the solid in the reaction kettle was washed with deionized water and anhydrous ethanol for three times respectively, dried at 60 °C overnight, and a yellow-green Co 0.2 Cd 0.8 S catalyst without vacancy was obtained.

[0049] The prepared yellow-green Co 0.2 Cd 0.8 S catalyst without vacancy was used for piezoelectric photocatalytic production of H2:

[0050] 2 mg Co 0.2 Cd 0.8 S catalyst, 18 mL water were weighed and mixed, ultrasonic dispersed for 0.5 h, then 2 mL of a sacrificial agent solution lactic acid was added, followed by 30 min N2, and finally sealed for 2 h under ultrasonic (240 W) and light (55 W xenon lamp simulating sunlight). After the experiment was completed, 0.5 mL of gas in a tube was extracted, and the peak area was detected by a gas chromatograph to calculate the production rate of H2, and the production rate of H2 was calculated to be 3.82 mmol / (g·h).

[0051] The prepared yellow-green Co 0.2 Cd 0.8 S catalyst without vacancy was used for piezoelectric photocatalytic production of H2O2

[0052] 5 mg Co 0.2 Cd 0.8 S was mixed with 10 mL distilled water, and dispersed for 0.5 h under ultrasonic (240 W) and light (55 W xenon lamp simulating sunlight) to make the catalyst uniformly dispersed in water, then 500 μL of the supernatant was taken and 2 mL of 0.1 mol / L potassium iodide solution and 50 μL of 0.01 mol / L ammonium molybdate solution were added, and after oscillation for 10 min, the absorbance value was measured at 352 nm by ultraviolet spectrophotometry to calculate the production rate of H2O2, and the production rate of H2O2 was calculated to be 86.8 μmol / (g·h).

[0053] Then 0.2 g Co 0.2 Cd 0.8 S and 0.8 g NaOH were dispersed in an aqueous solution, and ultrasonic dispersed for 20 min to obtain enough bubbles for obtaining Co 0.2 Cd 0.8S-Vs provide conditions, after the reaction is completed, the solid is separated at room temperature, washed and dried to obtain Co 0.2 Cd 0.8 S-Vs.

[0054] The prepared Co 0.2 Cd 0.8 S-Vs catalyst is applied to piezoelectric photocatalytic H2 production:

[0055] 2mg Co 0.2 Cd 0.8 S-Vs catalyst, 18mL water is mixed, ultrasonic dispersion is carried out for 0.5h, then 2mL of the sacrificial agent solution lactic acid is added, then N2 is passed for 30min, finally it is sealed for 2h under ultrasonic (240W) and light (55W xenon lamp simulating sunlight). After the experiment is completed, the gas in the 0.5mL tube is extracted, the peak area is detected by a gas chromatograph, the H2 production rate is calculated, and the analysis calculation shows that the H2 production rate is 5.13mmol / (g·h).

[0056] (2) 0.498g Co(CH3COO)2·4H2O and 0.22g Zn(CH3COO)2·2H2O are dispersed in 40ml distilled water and stirred and mixed, 0.36g CH4N2O and 0.074g NH4F are added and stirred and mixed, then the mixed solution is transferred to a reaction kettle lined with polytetrafluoroethylene, the reaction kettle is placed in an oven at 120℃ for 6h, after the reaction is completed, it is cooled to room temperature, the solid in the reaction kettle is washed with deionized water and anhydrous ethanol each three times, and dried at 60℃ overnight to obtain a purple ZnCo2O4 precursor. Finally, the precursor is placed in a tube furnace, heated to 400℃ at a rate of 5℃ / min, and calcined for 2h to obtain black ZnCo2O4.

[0057] The prepared ZnCo2O4 catalyst is applied to piezoelectric photocatalytic H2 production:

[0058] 2mg ZnCo2O4 catalyst, 18mL water is mixed, ultrasonic dispersion is carried out for 0.5h. Then 2mL of the sacrificial agent is added, the sacrificial agent solution is lactic acid, then N2 is passed for 30min, finally it is sealed for 2h under ultrasonic (240W) and light (55W xenon lamp simulating sunlight). After the experiment is completed, the gas in the 0.5mL tube is extracted, the peak area is detected by a gas chromatograph, the H2 production rate is calculated, and the analysis calculation shows that the H2 production rate is 6.9μmol / (g·h).

[0059] (3) Co 0.2 Cd 0.8 S-Vs, ZnCo2O4 is dissolved in deionized water, stirred at a stirring speed of 400r / min for 20h; filtered, washed and dried at room temperature, and finally orange powder is obtained, which is ZnCo2O4 / Co0.2 Cd 0.8 S-Vs composite catalyst, denoted as 3% ZnCo2O4 / Co 0.2 Cd 0.8 S-Vs. Wherein, the mass of ZnCo2O4 is Co 0.2 Cd 0.8 S-Vs quality is 3%.

[0060] The 3% ZnCo2O4 / Co prepared in Example 1 0.2 Cd 0.8 S-Vs are used for piezoelectric photocatalytic H2 production:

[0061] 2 mg 3% ZnCo2O4 / Co 0.2 Cd 0.8 S-Vs were mixed with 18 mL of distilled water and ultrasonically dispersed for 0.5 h to ensure uniform dispersion of the catalyst in the water. Then, 2 mL of sacrificial agent (lactic acid) was added, followed by N2 purging for 30 min. 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 a gas chromatograph to calculate the H2 production rate. The calculated H2 production rate was 12.78 mmol / (g·h).

[0062] The 3% ZnCo2O4 / Co prepared in Example 1 0.2 Cd 0.8 S-Vs are used for piezoelectric photocatalytic production of H2O2:

[0063] 5 mg 3% ZnCo2O4 / Co 0.2 Cd 0.8 S-Vs were mixed with 10 mL of distilled water and dispersed under ultrasonic (240 W) and light (55 W xenon lamp simulating sunlight) conditions for 0.5 h to ensure uniform dispersion of the catalyst in water. Then, 500 μL of the supernatant was taken and 2 mL of 0.1 mol / L potassium iodide solution and 50 μL of 0.01 mol / L ammonium molybdate solution were added. After shaking for 10 min, the absorbance was measured at 352 nm using a UV spectrophotometer, and the H2O2 production rate was calculated. The calculated H2O2 production rate was 542.92 μmol / (g·h).

[0064] Example 2

[0065] Compared with Example 1, the difference is that in step (3), the mass of ZnCo2O4 added is Co 0.2 Cd 0.8 S-Vs mass 1%, other parameters same as in Example 1, the resulting composite catalyst is denoted as 1% ZnCo2O4 / Co 0.2 Cd 0.8S-Vs.

[0066] The 1% ZnCo2O4 / Co 0.2 Cd 0.8 The S-Vs was applied to the piezophotocatalytic production of H2, and the application method was the same as that in Example 1, and the H2 production rate was 5.78 mmol / (g·h).

[0067] The 1% ZnCo2O4 / Co 0.2 Cd 0.8 The S-Vs was applied to the piezophotocatalytic production of H2O2, and the application method was the same as that in Example 1, and the H2O2 production rate was 103.8 μmol / (g·h).

[0068] Example 3

[0069] Compared with Example 1, the difference lies in that in step (3), the mass of ZnCo2O4 added is 5% of the mass of Co 0.2 Cd 0.8 The S-Vs mass is 5%, and the rest is the same as in Example 1, and the prepared composite catalyst is recorded as 5% ZnCo2O4 / Co 0.2 Cd 0.8 S-Vs.

[0070] The 5% ZnCo2O4 / Co 0.2 Cd 0.8 The S-Vs was applied to the piezophotocatalytic production of H2, and the application method was the same as that in Example 1, and the H2 production rate was 10.42 mmol / (g·h).

[0071] The 5% ZnCo2O4 / Co 0.2 Cd 0.8 The S-Vs was applied to the piezophotocatalytic production of H2O2, and the application method was the same as that in Example 1, and the H2O2 production rate was 337.57 μmol / (g·h).

[0072] Example 4

[0073] Compared with Example 1, the difference lies in that in step (3), the mass of ZnCo2O4 added is 7% of the mass of Co 0.2 Cd 0.8 The S-Vs mass is 7%, and the rest is the same as in Example 1, and the prepared composite catalyst is recorded as 7% ZnCo2O4 / Co 0.2 Cd 0.8 S-Vs.

[0074] The 7% ZnCo2O4 / Co 0.2 Cd 0.8S-Vs was applied to piezoelectric photocatalytic H2 production, the application method was the same as example 1, and the H2 production rate was 8.39 mmol / (g·h).

[0075] 7%ZnCo2O4 / Co 0.2 Cd 0.8 S-Vs was applied to piezoelectric photocatalytic H2O2 production, the application method was the same as example 1, and the H2O2 production rate was 309.2 μmol / (g·h).

[0076] Example 5

[0077] Compared with example 1, the difference was that in step (3), Co 0.2 Cd 0.8 S-Vs and ZnCo2O4 were dissolved in anhydrous ethanol, and the others were the same as example 1.

[0078] 3%ZnCo2O4 / Co 0.2 Cd 0.8 S-Vs was applied to piezoelectric photocatalytic H2 production, the application method was the same as example 1, and the H2 production rate was 6.19 mmol / (g·h).

[0079] Example 6

[0080] Compared with example 1, the difference was that in step (1), the addition amount of CoCl2·6H2O and Cd(CH3COO)2·2H2O was 0.0595 g and 0.5996 g, and the others were the same as example 1.

[0081] 3%ZnCo2O4 / Co 0.1 Cd 0.9 S-Vs was applied to piezoelectric photocatalytic H2 production, the application method was the same as example 1, and the H2 production rate was 1.45 mmol / (g·h).

[0082] Example 7

[0083] Compared with example 1, the difference was that in step (1), the addition amount of CoCl2·6H2O and Cd(CH3COO)2·2H2O was 0.1785 g and 0.4664 g, and the others were the same as example 1.

[0084] 3%ZnCo2O4 / Co 0.3 Cd 0.7 S-Vs was applied to piezoelectric photocatalytic H2 production, the application method was the same as example 1, and the H2 production rate was 7.81 mmol / (g·h).

[0085] Example 8

[0086] Compared with Example 1, the difference is that in step (1), the added amount of CoCl2·6H2O and Cd(CH3COO)2·2H2O is 0.238 g and 0.402 g respectively, and the other conditions are the same as in Example 1.

[0087] The 3% ZnCo2O4 / Co 0.4 Cd 0.6 The S-Vs were applied to the piezophotocatalytic production of H2, and the application method was the same as in Example 1, and the H2 production rate was 3.4 mmol / (g·h).

[0088] Comparative Example 1

[0089] Compared with Example 1, the difference is that in the application method, the ultrasonic (240 W) and light (55 W xenon lamp simulating sunlight) are replaced by only ultrasonic (240 W), and the other conditions are the same as in Example 1. 3% ZnCo2O4

[0090] / Co 0.2 Cd 0.8 The H2 production rate of the S-Vs catalyst was 408.48 μmol / (g·h).

[0091] Compared with Example 1, the difference is that in the application method, the ultrasonic (240 W) and light (55 W xenon lamp simulating sunlight) are replaced by only light (55 W xenon lamp simulating sunlight), and the other conditions are the same as in Example 1. 3% ZnCo2O4 / Co 0.2 Cd 0.8 The H2 production rate of the S-Vs catalyst was 1.79 mmol / (g·h).

[0092] Comparative Example 2

[0093] After mixing 0.119 g of CoCl2·6H2O and 0.533 g of Cd(CH3COO)2·2H2O, 0.381 g of C2H5NS dissolved in distilled water was added, stirred for 1 h, and then 25 ml of ethylenediamine was added and stirred for 1 h to make the mixture uniform, and then the mixture was transferred to a reaction kettle with a polytetrafluoroethylene liner, placed in an oven at 180°C for 12 h, and after the reaction was completed, cooled to room temperature, the solid in the reaction kettle was washed with deionized water and anhydrous ethanol three times each, and dried at 60°C overnight to obtain a yellow-green Co 0.2 Cd 0.8 S.

[0094] Co(CH3COO)2·4H2O and 0.22 g Zn(CH3COO)2·2H2O were dispersed in 40 ml distilled water and stirred, then 0.36 g CH4N2O and 0.074 g NH4F were added and stirred thoroughly, then the mixture was transferred into a reaction kettle lined with polytetrafluoroethylene, which was placed in an oven at 120℃ for 6 h. After the reaction was completed, the reaction kettle was cooled to room temperature, and the solid in the reaction kettle was washed with deionized water and anhydrous ethanol three times each, and dried at 60℃ overnight to obtain a purple powder of ZnCo2O4 precursor. Finally, the precursor was placed in a tube furnace and heated to 400℃ at a rate of 5℃ / min, and calcined for 2 h to obtain black ZnCo2O4.

[0095] Co 0.2 Cd 0.8 S, ZnCo2O4 was dissolved in deionized water and stirred at a stirring speed of 400 r / min for 20 h; filtered, washed, and dried at room temperature to obtain an orange powder, which was ZnCo2O4 / Co 0.2 Cd 0.8 S-Vs composite catalyst, denoted as 3% ZnCo2O4 / Co 0.2 Cd 0.8 S. The mass of ZnCo2O4 was 3% of the mass of Co 0.2 Cd 0.8 S.

[0096] The 3% ZnCo2O4 / Co 0.2 Cd 0.8 S catalyst prepared in Comparative Example 2 was used for piezophotocatalytic production of H2:

[0097] 2 mg of 3% ZnCo2O4 / Co 0.2 Cd 0.8 S was mixed with 18 mL of distilled water and ultrasonically dispersed for 0.5 h to uniformly disperse the catalyst in the water, then 2 mL of a sacrificial agent was added, the sacrificial agent solution was lactic acid, then N2 was passed for 30 min, and finally the mixture was sealed and subjected to ultrasonic treatment (240 W) and light irradiation (55 W xenon lamp simulating sunlight) for 2 h. After the experiment was completed, 0.5 mL of gas was extracted from the tube and subjected to gas chromatography to detect the peak area, and the rate of production of H2 was calculated. The rate of production of H2 was calculated to be 6.59 mmol / (g·h).

[0098] Comparative Example 3

[0099] CoCl2-6H2O, 0.533 g Cd(CH3COO)2-2H2O were mixed, 0.381 g C2H5NS dissolved in distilled water was added, stirred for 1 h, 25 ml ethylenediamine was further added and stirred for 1 h to make them mixed uniformly, then the mixture was transferred into a reaction kettle with polytetrafluoroethylene lining, placed in an oven at 180 °C for 12 h, after the reaction was completed, cooled to room temperature, the solid in the reaction kettle was washed with deionized water and anhydrous ethanol for three times, and dried at 60 °C overnight to obtain yellow-green Co 0.2 Cd 0.8 S without vacancy. 0.2 Cd 0.8 S and 0.8 g NaOH were dispersed in an aqueous solution, and ultrasonic treatment was performed for 20 min to obtain enough bubbles to provide conditions for Co 0.2 Cd 0.8 S-Vs. 0.2 Cd 0.8 S-Vs.

[0100] 0.631 g Bi(NO3)3-5H2O and 0.157 g Na2MoO4 were dispersed in 60 ml distilled water and mixed by stirring, then the mixture was transferred into a reaction kettle lined with polytetrafluoroethylene, and the reaction kettle was placed in an oven at 160 °C for 14 h, after the reaction was completed, cooled to room temperature, the solid in the reaction kettle was washed with deionized water and anhydrous ethanol for three times, and dried at 60 °C overnight to obtain yellow Bi2MoO6.

[0101] Co 0.2 Cd 0.8 S-Vs, Bi2MoO6 was dissolved in deionized water, and stirred at a stirring speed of 400 r / min for 20 h; filtered, washed and dried at room temperature, and finally orange powder was obtained, which was Bi2MoO6 / Co 0.2 Cd 0.8 S-Vs composite catalyst, denoted as 3% Bi2MoO6 / Co 0.2 Cd 0.8 S-Vs. Among them, the mass of Bi2MoO6 is 3% of the mass of Co 0.2 Cd 0.8 S-Vs.

[0102] The 3% Bi2MoO6 / Co 0.2 Cd 0.8 -Vs catalyst prepared in Comparative Example 3 was applied to piezoelectric photocatalytic H2 production:

[0103] 2 mg 3% Bi2MoO6 / Co 0.2 Cd 0.8Vs mixed with 18 mL distilled water, ultrasonic dispersion for 0.5 h, the catalyst was dispersed uniformly in water, then 2 mL of sacrificial agent was added, the sacrificial agent solution was lactic acid, then 30 min N2 was passed, finally under the condition of ultrasonic (240 W) and light (55 W xenon lamp simulated sunlight) for 2 h. After the experiment was completed, 0.5 mL of gas was extracted into a tube, and the peak area was detected by gas chromatography. The H2 production rate was calculated to be 5.18 mmol / (g·h).

[0104] The 3% Bi2MoO6 / Co 0.2 Cd 0.8 Vs catalyst for piezoelectric photocatalytic production of H2O2:

[0105] 5 mg of 3% Bi2MoO6 / Co 0.2 Cd 0.8 Vs mixed with 10 mL distilled water, ultrasonic dispersion for 0.5 h, the catalyst was dispersed uniformly in water, then 500 μL of supernatant was taken and 2 mL of 0.1 mol / L potassium iodide solution and 50 μL of 0.01 mol / L ammonium molybdate solution were added, and the absorbance value was measured at 352 nm by ultraviolet spectrophotometer after oscillation for 10 min. The H2O2 production rate was calculated to be 97.08 μmol / (g·h).

[0106] Based on the above ideal embodiments according to the present application, through the above description, relevant personnel can make various changes and modifications without deviating from the technical idea of the present application. The technical scope of the present application is not limited to the contents of the specification, and must be determined according to the scope of the claims.

Claims

1. A ZnCo2O4 / Co structure rich in sulfur vacancies 0.2 Cd 0.8 The S-Vs composite catalyst is characterized by, The catalyst is made of Co 0.2 Cd 0.8 S-Vs and ZnCo2O4 combine to form a heterojunction structure, wherein ZnCo2O4 is Co 0.2 Cd 0.8 S-Vs quality is 1-7%; The Co 0.2 Cd 0.8 The preparation method of S-Vs is as follows: CoCl2·6H2O and Cd(CH3COO)2·2H2O are mixed, and C2H5NS is added to dissolve it in distilled water. The mixture is stirred for 1 hour, and then ethylenediamine is added and stirred for another hour to ensure uniform mixing. The mixture is then transferred to a reaction vessel and placed in an oven at 180°C for 12 hours. After the reaction is completed, the mixture is cooled to room temperature. The solid in the reaction vessel is washed three times each with deionized water and anhydrous ethanol, and then dried at 60°C overnight to obtain yellow-green Co without vacancies. 0.2 Cd 0.8 S; then Co 0.2 Cd 0.8 S and NaOH were dispersed in an aqueous solution, and sufficient bubbles were obtained by sonication. After the reaction was completed, the solid was separated at room temperature, washed, and dried to obtain Co. 0.2 Cd 0.8 S-Vs.

2. The sulfur-vacancy-rich ZnCo2O4 / Co according to claim 1 0.2 Cd 0.8 The S-Vs composite catalyst is characterized by, The preparation method of ZnCo2O4 is as follows: Co(CH3COO)2·4H2O and Zn(CH3COO)2·2H2O are stirred and mixed in distilled water, then CH4N2O and NH4F are added and stirred thoroughly. The mixture is then transferred to a reaction vessel and placed in an oven at 120°C for 6 hours. After the reaction is completed, the mixture is cooled to room temperature. The solid in the reaction vessel is washed three times each with deionized water and anhydrous ethanol, and dried at 60°C overnight to obtain a pinkish-purple ZnCo2O4 precursor. Finally, the precursor is calcined in a tube furnace to obtain black ZnCo2O4.

3. The sulfur-vacancy-rich ZnCo2O4 / Co according to claim 2 0.2 Cd 0.8 The S-Vs composite catalyst is characterized by, The mass ratio of Co(CH3COO)2·4H2O to Zn(CH3COO)2·2H2O is 0.22:0.

498. In a tube furnace, the precursor is heated to 400℃ and calcined for 2 h at a rate of 5℃ / min.

4. The sulfur-vacancy-rich ZnCo2O4 / Co according to claim 1 0.2 Cd 0.8 The S-Vs composite catalyst is characterized by, The mass ratio of C2H5NS to CoCl2·6H2O is 0.119:0.381; the molar ratio of CoCl2·6H2O to Cd(CH3COO)2·2H2O is 1:4-1:

9.

5. A sulfur-vacancy-rich ZnCo2O4 / Co according to claim 1 0.2 Cd 0.8 The method for preparing S-Vs composite catalyst is characterized by, The preparation method of the composite catalyst is as follows: Co 0.2 Cd 0.8 S-Vs and ZnCo2O4 were dissolved in a solvent in a certain proportion. After stirring for 20-24 hours, the mixture was filtered, washed, and dried to obtain ZnCo2O4 / Co. 0.2 Cd 0.8 S-Vs composite catalyst.

6. A sulfur-vacancy-rich ZnCo2O4 / Co according to claim 1 0.2 Cd 0.8 The application of S-Vs composite catalysts is characterized by... The sulfur-vacancy-rich ZnCo2O4 / Co 0.2 Cd 0.8 S-Vs composite catalysts are used for photocatalytic hydrogen production or for photocatalytic H2O2 production.

7. The sulfur-vacancy-rich ZnCo2O4 / Co according to claim 6 0.2 Cd 0.8 The application of S-Vs composite catalysts is characterized by... The method for using the catalyst in photocatalytic hydrogen production is as follows: ZnCo2O4 / Co catalyst rich in sulfur vacancies is used... 0.2 Cd 0.8 The S-Vs composite catalyst is added to distilled water, fully dispersed, and then lactic acid is added. N2 is then introduced, and finally the reaction is carried out in a sealed environment under ultrasound and sunlight irradiation.

8. The sulfur-vacancy-rich ZnCo2O4 / Co according to claim 6 0.2 Cd 0.8 The application of S-Vs composite catalysts is characterized by: The method for using the catalyst in photocatalytic production of H2O2 is as follows: ZnCo2O4 / Co catalyst rich in sulfur vacancies is used... 0.2 Cd 0.8 The S-Vs composite catalyst was added to distilled water, fully dispersed, and then reacted under ultrasound and sunlight irradiation.

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