ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst and application of piezoelectric photocatalytic reduction of carbon dioxide

Abstract

The application belongs to the field of piezoelectric photocatalytic reduction of carbon dioxide, and particularly relates to ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst and application of piezoelectric photocatalytic reduction of carbon dioxide. The application first prepares a gel precursor of Ba 0.5 Sr 0.5 TiO3, and calcines the gel precursor to obtain white Ba 0.5 Sr 0.5 TiO3. A black cocatalyst ReS2 is synthesized through a hydrothermal reaction, and finally, a ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst is prepared through mechanical stirring and solvent evaporation. The catalyst has more excellent piezoelectric photocatalytic performance and rich reaction active sites. When the catalyst is applied to piezoelectric photocatalytic reduction of carbon dioxide, it shows stable and excellent reduction capacity of carbon dioxide under the synergistic effect of light and ultrasound, and expands the application of Ba 0.5 Sr 0.5 TiO3 in the field of piezoelectric photocatalytic reduction of carbon dioxide.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of piezoelectric photocatalysis, and particularly relates to a ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst, a preparation method and application thereof. BACKGROUND

[0002] Excessive carbon dioxide emissions have caused irreversible damage to the global environment, and converting excess carbon dioxide into high-energy value-added fuels is an important way to achieve environmental and energy sustainability. Among many methods, piezoelectric photocatalytic reduction of CO2 is undoubtedly one of the most effective and environmentally friendly ways. People have been committed to finding efficient visible light driven photocatalysts. More than a hundred photocatalysts have been reported for carbon dioxide conversion. However, most of these photocatalysts show limited activity under visible light. Since visible light accounts for 43% of solar energy, the low utilization of solar energy is a big limitation, however, the introduction of piezoelectricity can make the energy band structure of the material bend by generating an internal electric field, thereby realizing the rapid and effective separation of photo-generated electrons and holes. Currently, in the field of photocatalytic and piezoelectric photocatalytic reduction of carbon dioxide, it is common to add TEOA, lactic acid, triethanolamine and other sacrificial agents. Indeed, the addition of sacrificial agents can greatly improve the overall carbon dioxide reduction performance by donating electrons or promoting electron-hole separation. However, on the one hand, the addition of sacrificial agents will increase the overall cost, and if the catalytic time is too long, the subsequent replenishment of sacrificial agents needs to be considered, which is not conducive to subsequent large-scale application and implementation, on the other hand, the recovery and removal of sacrificial agents and the environmental pollution of sacrificial agents are also a big problem, which will also increase the difficulty and cost of catalysis. Therefore, considering the above many unchangeable factors, sacrificial agent-free pure water catalytic reduction of carbon dioxide is undoubtedly the preferred choice, which not only greatly reduces the overall experimental cost, but also is an environmentally friendly catalyst, which is conducive to the protection of the ecology and promotes the harmonious coexistence of man and ecology.

[0003] Barium strontium titanate (BST) is an important perovskite material with good piezoelectricity and high structural stability, and is an excellent material for photocatalytic reduction of carbon dioxide. Barium strontium titanate has a wide range of applications in sensors, capacitors and other aspects, ReS2 is occasionally used in photocatalytic reduction of carbon dioxide, but the application of piezoelectric light reduction of carbon dioxide is very rare. These examples are mostly limited to photocatalysis in a single aspect, in order to further improve the performance, the coupling of piezoelectricity and photocatalysis is imperative. Therefore, it is very important to study the efficiency of barium strontium titanate in piezoelectric photocatalytic reduction of carbon dioxide. At the same time, barium strontium titanate has excellent piezoelectricity, but poor light absorption, so the application introduces a good light absorption performance of the ReS2 catalyst, aiming at improving the light absorption capacity and accelerating the transfer speed of the electron, thereby greatly improving the photocatalytic performance. SUMMARY

[0004] The purpose of the present application is to prepare a ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst, and apply it to piezoelectric photocatalytic reduction of carbon dioxide, which has higher piezoelectric photocatalytic activity and carbon dioxide reduction capacity than pure substances.

[0005] The ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst prepared by the present application has the following preparation method:

[0006] (1) Preparation of Ba 0.5 Sr 0.5 TiO3 catalyst:

[0007] Tetrabutyl titanate is added to anhydrous ethanol, stirred for 25 min, then BaCO3 and SrCO3 are added, ultrasonic treatment for 90 min, stirring for 30 min, to obtain solution A. Deionized water, HCl and anhydrous ethanol are mixed and stirred for 25 min to obtain solution B. Then solution B is added dropwise into solution A to obtain a mixed solution in gel state, then vacuum drying overnight to obtain a dry gel barium strontium titanate precursor. Then the Ba 0.5 Sr 0.5 TiO3 is prepared by a solid phase method, a certain amount of precursor is put into a tube furnace and calcined to obtain white product Ba 0.5 Sr 0.5 TiO3 (abbreviated as BST).

[0008] Further, the molar ratio of BaCO3 and SrCO3 is 1:1; the molar ratio of BaCO3 and tetrabutyl titanate is 1:2; the volume ratio of deionized water, HCl and anhydrous ethanol is 10:3.3:50.

[0009] The tube furnace calcination temperature is 800-900℃, and the calcination time is 6-10h.

[0010] (2) Preparation of ReS2 catalyst:

[0011] NH4ReO4 and thiourea were added to a certain amount of deionized water, ultrasonic treatment for a period of time, and then stirred for 1h. Then the above mixed solution was added to a polytetrafluoroethylene lined autoclave, and hydrothermal reaction was carried out at 240℃ for 24h. After the reaction, it was cooled to room temperature, and the obtained black reaction was washed repeatedly with deionized water and ethanol, and then vacuum dried at 60℃ overnight, finally black product ReS2 was obtained (abbreviated as RS).

[0012] Further, the molar ratio of NH4ReO4 and thiourea is 2:9.

[0013] (3) Preparation of ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst:

[0014] ReS2 and Ba 0.5 Sr 0.5 TiO3 were dispersed in a certain amount of solvent, after ultrasonic treatment, stirring, filtration, washing and drying, ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst was obtained.

[0015] Further, the added mass of ReS2 is 5-15% of the mass of Ba 0.5 Sr 0.5 TiO3.

[0016] Further, the solvent includes deionized water.

[0017] Further, the ultrasonic power is 240W, and the time is 1h; the stirring speed is 400r / min, and the time is 24h.

[0018] The ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst prepared by the above method is used for piezophotocatalytic reduction of carbon dioxide, and the specific application method is as follows: the ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst is added to water and ultrasonically dispersed uniformly, without adding additional sacrificial agent, then CO2 is introduced, and finally piezophotocatalytic reduction of carbon dioxide is carried out under the conditions of ultrasonic and light.

[0019] Further, the ultrasonic power is 240W; the light is sunlight.

[0020] Further, the ReS2 / Ba 0.5 Sr 0.5 The amount of the ReS2 / Ba

[0021] The present application has the following advantages:

[0022] (1) The present application greatly reduces the temperature of solid phase method firing by preparing the precursor of barium strontium titanate, greatly reduces the risk of experiment, has the advantages of simple preparation process and safety. The present application expands the application of Ba 0.5 Sr 0.5 TiO3 and ReS2 in the field of piezoelectric photocatalytic reduction of carbon dioxide.

[0023] (2) The catalyst material of the present application has the advantages of simple, fast, safe, efficient, pollution-free, low preparation cost and the like in preparation and compounding process. The simple mechanical stirring and solvent evaporation method is simple and efficient, and the EDS element mapping shows that the compounding is sufficient and uniform.

[0024] (3) The present application aims to add the assistant catalyst ReS2, which shows lower overpotential, better light response, better photocatalytic activity and ability under the same current density. At the same time, the smaller Tafel slope also indicates the enhanced reduction of carbon dioxide activity and the improved CO production rate. The present application prepares the Z-type heterojunction with close combination by simple mechanical stirring and solvent evaporation method, improves the separation efficiency of electron-hole pairs, and further enhances the overall reduction of carbon dioxide activity. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is the scanning electron microscope image of the ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst synthesized in Example 1;

[0026] Figure 2 is the scanning electron microscope image of ReS2 and Ba 0.5 Sr 0.5 TiO3 pure substance;

[0027] Figure 3 is the XRD image of the ReS2, Ba 0.5 Sr 0.5 TiO3 catalyst;

[0028] Figure 4 is the XRD image of the Ba x Sr 1-x TiO3 catalyst with different Ba, Sr ratios;

[0029] Figure 5 XRD pattern of ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalysts;

[0030] Figure 6 CO production rate performance plot of catalyst synthesized in Example 1-7 under piezoelectric and light combination;

[0031] Figure 7 CO production rate performance plot of catalyst synthesized in Example 1-7 under piezoelectric only;

[0032] Figure 8 CO production rate performance plot of catalyst synthesized in Example 1-7 under light only;

[0033] Figure 9 XRD pattern of Ba 0.5 Sr 0.5 TiO3 and ReS2 / Ba 0.5 Sr 0.5 Electrochemical LSV plot of Ba

[0034] Figure 10 XRD pattern of Ba 0.5 Sr 0.5 TiO3 and ReS2 / Ba 0.5 Sr 0.5 Electrochemical Tafel plot of Ba

[0035] Figure 11 XRD pattern of Ba 0.5 Sr 0.5 TiO3 calcined at 700 °C and 800 °C.

[0036] Figure 12 XPS spectra of Ba 0.5 Sr 0.5 TiO3, ReS2 and ReS2 / Ba 0.5 Sr 0.5 XPS spectra of Ba

[0037] Figure 13 Mechanism of Ba 0.5 Sr 0.5 TiO3 and ReS2 for piezophotocatalytic reduction of carbon dioxide. DETAILED DESCRIPTION

[0038] The present application is not limited to the following specific embodiments, and those skilled in the art can implement the present application in other various embodiments 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, and all fall within the protection 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.

[0039]

[0040] R: CO yield, unit: μmol / (g·h)

[0041] S: Peak area of CO in the gas chromatograph

[0042] m: Catalyst mass, unit: g

[0043] t: Time, unit: h.

[0044] Example 1

[0045] (1) 13.89 ml of tetrabutyl titanate was added into 37.5 ml of anhydrous ethanol, and stirred thoroughly for 25 min, then 3.946 g of BaCO3 and 2.952 g of SrCO3 were added, and ultrasonic treatment was performed for 90 min, and stirring was performed for 30 min, to obtain solution A. 10 ml of deionized water, 3.3 ml of HCl and 50 ml of anhydrous ethanol were mixed and stirred for 25 min, to obtain solution B. Then, 13.3 ml of solution B was added dropwise into solution A, to obtain a mixed solution, and then vacuum drying was performed overnight, to obtain a dry gel of a barium strontium titanate precursor. Then, Ba 0.5 Sr 0.5 TiO3 was prepared by a solid phase method, and a certain amount of the precursor was placed into a tube furnace, and calcination was performed at 800℃ for 8 h, to obtain a white product of Ba 0.5 Sr 0.5 TiO3 (abbreviated as BST).

[0046] (2) 2 mmol of NH4ReO4 and 9 mmol of thiourea were added into 60 ml of deionized water, and ultrasonic treatment was performed for a period of time, and then stirring was performed for 1 h. Then, the above mixed solution was added into a polytetrafluoroethylene-lined hydrothermal reactor, and hydrothermal reaction was performed at a high temperature of 240℃ for 24 h. After the reaction was completed, cooling was performed to room temperature, and the obtained black reaction product was repeatedly washed with deionized water and ethanol, and then vacuum drying was performed at 60℃ overnight, to finally obtain a black product of ReS2 (abbreviated as RS).

[0047] (3) ReS2 and Ba 0.5 Sr 0.5TiO3 was dispersed in deionized water, and then was dispersed uniformly by ultrasonic (ultrasonic power was 240 W, ultrasonic time was 1 h), stirring (stirring speed was 400 r / min, stirring time was 24 h), filtration, washing, and drying to obtain a gray composite catalyst. That is, ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst; wherein the mass of ReS2 added in step (3) was 10% of the mass of ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst. 0.5 Sr 0.5 TiO3.

[0048] (4) The 10% ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst prepared in Example 1 was used for piezoelectric photocatalytic reduction of carbon dioxide.

[0049] 2 mg of the 10% ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst was added into 20 ml of water, and was dispersed uniformly by ultrasonic. Without adding a sacrificial agent, CO was then introduced for 30 min, and finally, under the conditions of ultrasonic (240 W) and light (55 W xenon lamp simulating sunlight), the reaction was carried out in a closed system for 2 h. After the experiment was completed, 0.5 mL of gas was extracted from a tube, and the peak area was detected by a gas chromatograph to calculate the CO yield. The CO yield was 23.80 μmol / (g·h).

[0050] Example 2

[0051] Compared with Example 1, the difference lies in that the mass of the ReS2 added in step (3) was 5% of the mass of ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst. Other experimental conditions were consistent with those in Example 1. It is recorded as 5% ReS2-Ba 0.5 Sr 0.5 TiO3.

[0052] The 5% ReS2-Ba 0.5 Sr 0.5 TiO3 prepared in Example 2 was used for piezoelectric photocatalytic reduction of carbon dioxide, and the experimental conditions were consistent with those in Example 1. The CO yield was 9.65 μmol / (g·h).

[0053] Example 3

[0054] Compared with Example 1, the difference lies in that the mass of the ReS2 added in step (3) was 5% of the mass of ReS2 / Ba 0.5 Sr 0.57.5% ReS2-BaTiO3 composite catalyst. Other experimental conditions are the same as in Example 1. Denoted as 7.5% ReS2-Ba 0.5 Sr 0.5 TiO3.

[0055] 7.5% ReS2-BaTiO3 prepared in Example 3 was used for piezocatalytic reduction of carbon dioxide. The experimental conditions were the same as in Example 1, and the CO yield was 13.58 pmol / (g-h). 0.5 Sr 0.5 TiO3.

[0056] Example 4

[0057] Comparing with Example 1, the difference is that the mass of the promoter ReS2 added in step (3) is ReS2 / Ba 0.5 Sr 0.5 12.5% ReS2-BaTiO3 composite catalyst. Other experimental conditions are the same as in Example 1. Denoted as 12.5% ReS2-Ba 0.5 Sr 0.5 TiO3.

[0058] 12.5% ReS2-BaTiO3 prepared in Example 4 was used for piezocatalytic reduction of carbon dioxide. The experimental conditions were the same as in Example 1, and the CO yield was 9.19 pmol / (g-h). 0.5 Sr 0.5 TiO3.

[0059] Example 5

[0060] Comparing with Example 1, the difference is that the mass of the promoter ReS2 added in step (3) is ReS2 / Ba a0.5 Sr 0.5 15% ReS2-BaTiO3 composite catalyst. Other experimental conditions are the same as in Example 1. Denoted as 15% ReS2-Ba 0.5 Sr 0.5 TiO3.

[0061] 15% ReS2-BaTiO3 prepared in Example 5 was used for piezocatalytic reduction of carbon dioxide. The experimental conditions were the same as in Example 1, and the CO yield was 4.38 pmol / (g-h). 0.5 Sr 0.5 TiO3.

[0062] Example 6

[0063] The catalyst in Example 6 is pure Ba 0.5 Sr 0.5 TiO3. The preparation method is the same as step (1) in Example 1.

[0064] The pure substance BaTiO3 of Example 6 was used for the piezocatalytic reduction of carbon dioxide, and the remaining experimental conditions were consistent with those of Example 1, and the CO yield was 2.29 μmol / (g·h). 0.5 Sr 0.5 TiO3 was used for the piezocatalytic reduction of carbon dioxide, and the remaining experimental conditions were consistent with those of Example 1, and the CO yield was 2.29 μmol / (g·h).

[0065] Example 7

[0066] The catalyst of Example 7 was the pure substance ReS2. The preparation method was consistent with step (2) of Example 1.

[0067] The pure substance ReS2 of Example 7 was used for the piezocatalytic reduction of carbon dioxide, and the experimental conditions were consistent with those of Example 1, and the CO yield was 2.81 μmol / (g·h).

[0068] Comparative Example 1

[0069] Compared with Examples 1-7, the catalysts were the same, and the difference was that the experimental conditions during the piezophotocatalytic hydrogen production experiment were changed from the ultrasonic (240 W) and light (55 W xenon lamp simulating sunlight) synergistic conditions to only ultrasonic (240 W) conditions. The other experimental conditions were consistent with those of Examples 1-7. The measured CO yield is shown in Table 1. Figure 7 .

[0070] Comparative Example 2

[0071] Compared with Examples 1-7, the catalysts were the same, and the difference was that the experimental conditions during the piezophotocatalytic hydrogen production experiment were changed from the ultrasonic (240 W) and light (55 W xenon lamp simulating sunlight) synergistic conditions to only light (55 W xenon lamp simulating sunlight) conditions. The other experimental conditions were consistent with those of Examples 1-7. The measured CO yield is shown in Table 1. Figure 8 .

[0072] Comparative Example 3

[0073] Compared with Example 1, the difference was that in step (4), the amount of catalyst used in the piezophotocatalytic hydrogen production experiment was changed from 2 mg to 1 mg, and the other conditions were consistent with those of Example 1, and the CO yield was 16.57 μmol / (g·h).

[0074] Comparative Example 4

[0075] Compared with Example 1, the difference was that in step (4), the amount of catalyst used in the piezophotocatalytic hydrogen production experiment was changed from 2 mg to 3 mg, and the other conditions were consistent with those of Example 1, and the CO yield was 4.89 μmol / (g·h).

[0076] Comparative Example 5

[0077] Comparative example 1, the difference is that in step (4), the amount of catalyst used in the piezoelectric light hydrogen production experiment is changed from 2 mg to 5 mg, and the other conditions are the same as in example 1. The CO yield is 3.90 μmol / (g·h).

[0078] With the increase of the amount of catalyst added, mutual shielding between catalysts may occur, leading to poor light absorption effect, reduced piezoelectric effect, and reduced actual reaction active sites. Therefore, too much catalyst added may reduce the overall reaction rate, which is not conducive to the piezoelectric photocatalytic reduction of carbon dioxide.

[0079] Comparative example 6

[0080] Comparative example 1, the difference is that in step (3), the composite solvent is changed from deionized water to ethanol, and the other conditions are the same as in example 1. The CO yield is 6.32 μmol / (g·h).

[0081] The catalyst has better dispersibility in water and better composite effect than ethanol. After the composite is completed, the composite with water as the solvent only needs to be left for a few moments, and the composite can be deposited at the bottom, making it easier to separate from water and facilitating subsequent drying. The composite with ethanol as the solvent will not deposit at the bottom no matter how long it is left, which will affect the subsequent drying and thus the actual composite effect.

[0082] Comparative example 7

[0083] Comparative example 1, the difference is that in step (3), the composite solvent is changed from deionized water to half ethanol and half deionized water, and the other conditions are the same as in example 1. The CO yield is 14.19 μmol / (g·h).

[0084] Comparative example 8

[0085] Comparative example 1, the difference is that in step (1), the molar ratio of raw materials BaCO3 and SrCO3 is changed from 1:1 to 3:7 during preparation, and the other conditions are the same as in example 1. The composite catalyst obtained is named 10% ReS2-Ba 0.3 Sr 0.7 TiO3.

[0086] The 10% ReS2-Ba 0.3 Sr 0.7 TiO3 of comparative example 8 is used for piezoelectric catalytic reduction of carbon dioxide, and the experimental conditions are the same as in example 1. The CO yield is 5.18 μmol / (g·h).

[0087] Comparative example 9

[0088] The difference between Example 1 is that in step (1), the molar ratio of raw materials BaCO3 and SrCO3 is changed from 1:1 to 7:3, and other conditions are the same as Example 1. The obtained composite catalyst is named as 10% ReS2-Ba 0.7 Sr 0.3 TiO3.

[0089] The 10% ReS2-Ba 0.7 Sr 0.3 TiO3 of Comparative Example 9 is used for piezocatalytic reduction of carbon dioxide, and the experimental conditions are the same as Example 1. The CO yield is 17.09 μmol / (g·h).

[0090] Comparative Example 10

[0091] The catalyst of Comparative Example 10 is pure BaTiO3. The preparation method is the same as step (1) of Example 1, except that no SrCO3 is added during preparation.

[0092] The BaTiO3 of Comparative Example 10 is used for piezocatalytic reduction of carbon dioxide, and the experimental conditions are the same as Example 1. The CO yield is 1.72 μmol / (g·h).

[0093] Comparative Example 11

[0094] The catalyst of Comparative Example 10 is pure SrTiO3. The preparation method is the same as step (1) of Example 1, except that no BaCO3 is added during preparation.

[0095] The pure SrTiO3 catalyst of Comparative Example 11 is used for piezocatalytic reduction of carbon dioxide, and the experimental conditions are the same as Example 1. The CO yield is 2.03 μmol / (g·h).

[0096] Comparative Example 12

[0097] The difference between Example 1 is that in step (3), the added co-catalyst is changed from ReS2 to Co9S8, and the obtained composite catalyst is named as 10% Co9S8-Ba 0.5 Sr 0.5 TiO3.

[0098] The 10% Co9S8-Ba 0.5 Sr 0.5 TiO3 of Comparative Example 12 is used for piezocatalytic reduction of carbon dioxide, and the experimental conditions are the same as Example 1. The CO yield is 15.14 μmol / (g·h).

[0099] Comparative Example 13

[0100] The difference relative to Example 1 is that in step (3), the promoter added during compounding is changed from ReS2 to Cu7S4, and the obtained composite catalyst is named as 10% Cu7S4-Ba 0.5 Sr 0.5 TiO3.

[0101] The 10% Cu7S4-Ba 0.5 Sr 0.5 TiO3 of Comparative Example 13 is used for piezocatalytic reduction of carbon dioxide, and the experimental conditions are consistent with those of Example 1, and the CO yield is 5.24 μmol / (g·h).

[0102] Comparative Example 14

[0103] The difference relative to Example 1 is that in step (1), the calcination temperature in the solid phase method is changed from 800°C to 700°C, and other conditions are consistent with those of Example 1, and the obtained composite catalyst is named as 700-10% ReS2-Ba 0.5 Sr 0.5 TiO3.

[0104] The 700-10% ReS2-Ba 0.5 Sr 0.5 TiO3 of Comparative Example 14 is used for piezocatalytic reduction of carbon dioxide, and the experimental conditions are consistent with those of Example 1, and the CO yield is 1.65 μmol / (g·h). This is because the calcination at 700°C cannot accurately prepare Ba 0.5 Sr 0.5 TiO3. The characteristic peaks on the XRD cannot be accurately matched with the PDF card, and a large number of impurity peaks exist, indicating that 700°C cannot form Ba 0.5 Sr 0.5 TiO3 well, and a large number of intermediate impurities exist. The specific XRD chart is shown in Figure 11 .

[0105] The above examples are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst characterized by, ReS2and Ba 0.5 Sr 0.5 TiO3after mixing, ReS2 / Ba 0.5 Sr 0.5 TiO3composite; the ReS2is Ba 0.5 Sr 0.5 TiO3in an amount of 5-15%.

2. A ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst according to claim 1, characterized by ReS2 and Ba 0.5 Sr 0.5 TiO3 into deionized water, and then through ultrasonic, stirring and compounding treatment, and then filtering, washing, drying, finally obtaining ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst.

3. The ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst according to claim 2, characterized by ReS2 is Ba 0.5 Sr 0.5 TiO3 mass 7.5-10%.

4. The ReS2 / Ba 0.5 Sr 0.5 A method for preparing a ReS2 / Ba Ba 0.5 Sr 0.5 The preparation method of TiO3 is as follows: tetrabutyl titanate is added into anhydrous ethanol, BaCO3 and SrCO3 are added after fully stirring, and a solution A is obtained by ultrasonic treatment; deionized water, HCl and anhydrous ethanol are mixed and stirred to obtain a solution B; then the solution B is added dropwise into the solution A to obtain a mixed solution in a gel state, and then the mixed solution is vacuum dried overnight to obtain a dry gel strontium barium titanate precursor; a certain amount of the precursor is put into a tube furnace, and the white product Ba 0.5 Sr 0.5 TiO3 is obtained by fully calcining; the molar ratio of BaCO3 and SrCO3 is 1:1, the calcination temperature of the tube furnace is 800-900℃, and the calcination time is 6-10h.

5. A ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst for the piezophotocatalytic reduction of carbon dioxide, characterized in that, ReS2 / Ba 0.5 Sr 0.5 TiO3 composite catalyst is added to water, uniformly dispersed, then CO2 is passed in, and piezophotocatalytic reduction of carbon dioxide is carried out under the synergistic action of ultrasonic and light.

6. Use according to claim 5, characterized in that, The ultrasonic power is 200-300 W; and the light source is sunlight.

7. Use according to claim 5, characterized in that, The ReS2 / Ba 0.5 Sr 0.5 The amount of the TiO3 composite catalyst used in water is 1-5 mg / 20 mL.

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