阅读说明：本技术 一种以碳布为衬底的ZnO/MoS2(CC/ZnO/MoS2)复合材料光催化剂的制备方法 (ZnO/MoS with carbon cloth as substrate2(CC/ZnO/MoS2) Preparation method of composite material photocatalyst ) 是由 仉亚波 秦文静 印寿根 郑恺 古长顺 李文玲 刘宝生 于 2020-05-22 设计创作，主要内容包括：本发明涉及一种以碳布为衬底的ZnO/MoS-(2)(CC/ZnO/MoS-(2))复合材料光催化剂的制备方法,通过两步水热法将MoS-(2)纳米片固定在ZnO纳米棒上,得到一种廉价高效的光催化剂。第一步水热法以Zn(NO)-(3)·6H-(2)O和HMT(六次甲基四胺)为前驱体在导电碳布(CC)上生成了ZnO纳米棒；第二步水热法,以二水合钼酸钠和硫脲为钼源和硫源,在CC/ZnO上生长了MoS-(2)纳米片,即可获得CC/ZnO/MoS-(2)复合材料光催化剂。本发明CC/ZnO/MoS-(2)复合材料光催化剂,MoS-(2)的窄带隙增强了复合材料的光吸收范围,纳米片状的MoS-(2)为光催化反应提供了大量的活性位点,大量的ZnO/MoS-(2)界面提供了载流子分离的场所,棒状的ZnO促进了载流子的传输,最终提高了复合材料的光催化效率。(The invention relates to a ZnO/MoS with carbon cloth as a substrate 2 (CC/ZnO/MoS 2 ) A preparation method of a composite material photocatalyst comprises the step of carrying out a two-step hydrothermal method on MoS 2 The nano-sheet is fixed on the ZnO nano-rod to obtain the cheap and efficient photocatalyst. First hydrothermal method with Zn (NO) 3 ·6H 2 Generating ZnO nanorods on conductive Carbon Cloth (CC) by using O and HMT (hexamethylenetetramine) as precursors; first, theA two-step hydrothermal method, sodium molybdate dihydrate and thiourea are used as a molybdenum source and a sulfur source, and MoS is grown on CC/ZnO 2 Nanosheet to obtain CC/ZnO/MoS 2 A composite photocatalyst. The invention is CC/ZnO/MoS 2 Composite photocatalyst, MoS 2 The narrow band gap enhances the light absorption range of the composite material, and the nano flaky MoS 2 Provides a large number of active sites for photocatalytic reaction, and a large number of ZnO/MoS 2 The interface provides a place for separating carriers, and the rodlike ZnO promotes the transmission of the carriers, so that the photocatalytic efficiency of the composite material is finally improved.)

1. ZnO/MoS with carbon cloth as substrate₂(CC/ZnO/MoS₂) A preparation method of a composite material photocatalyst comprises the step of carrying out a two-step hydrothermal method on MoS₂Fixing of nanosheet toThe cheap and efficient photocatalyst is obtained on the ZnO nano-rod. First hydrothermal method with Zn (NO)₃·6H₂Generating ZnO nanorods on conductive Carbon Cloth (CC) by using O and HMT (hexamethylenetetramine) as precursors; a second step of hydrothermal method, sodium molybdate dihydrate and thiourea are used as a molybdenum source and a sulfur source, and MoS is grown on CC/ZnO₂Nanosheet to obtain CC/ZnO/MoS₂A composite photocatalyst.

2. CC/ZnO/MoS according to claim 1₂The preparation method of the composite material photocatalyst is characterized by comprising the following steps: the required carbon cloth substrate is subjected to hydrophilic treatment and pretreatment.

3. CC/ZnO/MoS according to claim 1₂The preparation method of the composite material photocatalyst is characterized by comprising the following steps: first hydrothermal method weighing 0.0025M Zn (NO)₃·6H₂O and 0.0025M HMT (hexamethylenetetramine) were dissolved in 50mL of deionized water with stirring.

4. CC/ZnO/MoS according to claim 1₂The preparation method of the composite material photocatalyst is characterized by comprising the following steps: the reaction temperature of the first hydrothermal method is 100 ℃, and the reaction time is 12 h.

5. CC/ZnO/MoS according to claim 1₂The preparation method of the composite material photocatalyst is characterized by comprising the following steps: in the second hydrothermal method, 0.005M sodium molybdate dihydrate and 0.03M thiourea are weighed and added into 35mL deionized water to be stirred and dissolved.

6. CC/ZnO/MoS according to claim 1₂The preparation method of the composite material photocatalyst is characterized by comprising the following steps: the second step hydrothermal method has the reaction temperature of 200 ℃ and the reaction time of 1-9 h.

7. CC/ZnO/MoS prepared according to claims 1 to 6₂Use of a composite photocatalyst, characterized in that it is used as a photocatalyst for the degradation of methylene blue dyes. In particular, the present inventionCC/ZnO/MoS prepared by invention₂The composite material is MoS₂The nano-sheet is fixed on the ZnO nano-rod, and the composite material is grown on the conductive carbon cloth and is easy to recycle. Meanwhile, compared with the rod-shaped ZnO and the sheet-shaped ZnO, the one-dimensional structure of the ZnO nanorod can promote the transmission of current carriers, improve the separation rate of the current carriers and further effectively improve the photocatalytic activity.

Technical Field

The invention relates to a ZnO/MoS with carbon cloth as a substrate₂(CC/ZnO/MoS₂) A preparation method of a composite material photocatalyst belongs to the technical field of photocatalysts.

Background

MoS₂Is one of the most stable layered Transition Metal Dihalides (TMDs), has high electron mobility, rich active sites and no toxicity, and is considered as an emerging high-efficiency photocatalytic material^[68]. Massive MoS₂The indirect band gap is 1.2eV, and the redox ability is insufficient. MoS due to quantum size limitation₂The nano-sheet has a direct band gap of 1.8eV, and an adjustable energy level structure is suitable for a photocatalysis process. However, the high recombination rate of photogenerated electron-hole pairs severely limits their performance. In order to suppress the carrier recombination rate, modification of noble metal nanoparticles and recombination with other semiconductor materials are two common strategies. Zinc oxide is of great interest due to its direct band structure, higher exciton binding energy (60meV), higher electron mobility, good chemical and thermal stability, and diverse morphology. The excellent chemical and physical properties make zinc oxide a multifunctional material, and the zinc oxide is widely applied to the fields of electronics, photoelectrons, catalysis, sensors and the like.

The powdery photocatalyst is dispersed in the solution, is not easy to recycle, and in addition, secondary pollution can be caused due to incomplete treatment. Growing or coating nano-sized photocatalyst on Carbon Cloth (CC) is expected to solve this problem. Carbon cloth has a series of advantages of low cost, high surface area, flexibility, cohesiveness, excellent conductivity and good thermal stability, and is a preferred substrate for supporting photocatalysts.

The method takes carbon cloth as a substrate and adopts a two-step hydrothermal method to prepare the CC/ZnO/MoS₂A composite material of a heterojunction structure. Mixing MoS₂The ZnO nano-rod is loaded on the ZnO nano-rod, so that on one hand, the light absorption performance of the material is enlarged; on the other hand, MoS₂The composite material is fixed on a ZnO nano rod, so that the specific surface area is increased, active sites are increased, and the photocatalytic degradation efficiency of the composite material is enhanced.

Disclosure of Invention

The invention aims to provide CC/ZnO/MoS₂The preparation method of the composite material photocatalyst is used for investigating the performance of the composite material photocatalyst in photocatalytic degradation of methylene blue under visible light. The preparation process is simple and easy to control, the operation is convenient, the repeatability is strong, and the photocatalyst loaded on the carbon cloth substrate has the advantage of easy recovery.

The technical scheme of the invention is as follows:

CC/ZnO/MoS₂The preparation method of the composite material photocatalyst mainly comprises the following steps

Step S1: preparation of CC/ZnO

Weighing 0.0025M Zn (NO)₃·6H₂Dissolving O and 0.0025M HMT (hexamethylenetetramine) into 50mL of deionized water, magnetically stirring for 1h until the solution is completely dissolved, pouring the solution into a reaction kettle, then placing carbon cloth into the reaction kettle, sealing the reaction kettle, and then placing the reaction kettle into a vacuum drying oven at 100 ℃ for 12 h. And (3) after the reaction is finished and the carbon cloth is cooled, washing the carbon cloth for 3 times by using deionized water and ethanol respectively, and annealing the carbon cloth for 1 hour in a muffle furnace at the temperature of 450 ℃ to obtain the CC/ZnO nanorod.

Step S2: CC/ZnO/MoS₂Preparation of

Weighing 0.005M sodium molybdate dihydrate and 0.03M thiourea, placing the mixture in a beaker, then adding 35mL of deionized water respectively, carrying out magnetic stirring for 30min until the mixture is completely dissolved, then pouring all the solution into a 50mL polytetrafluoroethylene reaction kettle, then placing carbon cloth with ZnO nanorods in the reaction kettle, finally sealing the reaction kettle, and placing the reaction kettle in an oven to keep the temperature of the reaction kettle at 200 ℃ for reaction for 1-9 h. Reaction ofAfter the reaction kettle is naturally cooled to the room temperature, the carbon cloth is taken out and is thoroughly washed clean by deionized water and ethanol. Obtaining CC/ZnO/MoS₂A composite material.

The hydrothermal reaction time in step S2 is 1 h.

The hydrothermal reaction time in step S2 was 3 h.

The hydrothermal reaction time in step S2 was 6 h.

The hydrothermal reaction time in step S2 was 9 h.

The principle of the invention is MoS₂The narrow band gap enhances the light absorption range of the composite material, and the nano flaky MoS₂Provides a large number of active sites for photocatalytic reaction, and a large number of ZnO/MoS₂The interface provides a place for separating carriers, and the rodlike ZnO promotes the transmission of the carriers, so that the photocatalytic efficiency of the composite material is finally improved.

The invention has the advantages and beneficial effects that:

(1) the invention is CC/ZnO/MoS₂The preparation process of the photocatalyst of the composite material is simple and easy to control, the operation is convenient and the price is low.

(2) The invention is CC/ZnO/MoS₂The composite material is a nano-flaky MoS₂Nano-sheet MoS fixed on ZnO nano-rod₂Provides a large number of active sites for photocatalytic reaction, and a large number of ZnO/MoS₂The interface provides a place for separating carriers, and the rodlike ZnO promotes the transmission of the carriers, so that the photocatalytic efficiency of the composite material is finally improved.

(3) The invention is CC/ZnO/MoS₂The composite material is simple in use mode. The catalyst with the substrate can be used only by putting the catalyst into sewage and then irradiating the catalyst by natural light at normal temperature and normal pressure; and has the advantages of easy recovery and no secondary pollution.

Drawings

FIG. 1 shows different MoS₂SEM image of growth time sample. The carbon cloth is a material composed of ultra-long carbon fibers woven and overlapped with each other, and each carbon fiber has a smooth and flat surface with a diameter of about 8 μm. As can be seen in the graph (e), ZnO nanorods vertically and uniformly grown on carbonOn the fiber, the diameter was about 200 nm. MoS₂When the reaction time is 1-3 h, MoS₂Starting to grow on the surface of the ZnO nano-rod; when the time is increased to 6h, a large amount of MoS is generated on the surface of the ZnO nano-rod₂Nanosheets, forming spherical aggregates, MoS, on the tops of ZnO nanorods₂The thickness of the nano-sheet is about 20 nm; while the time increased to 9h, MoS₂The diameter of the sphere made of the nanosheets becomes larger, while the individual MoS₂The thickness of the nanoplatelets did not change significantly.

Figure 2 is an XRD pattern of different samples. MoS₂When the reaction time is 1h, ZnO with a wurtzite structure is mainly contained in the XRD pattern of the sample, wherein diffraction peaks with the 2 theta of 31.74 degrees, 34.48 degrees, 36.21 degrees, 47.53 degrees, 56.62 degrees and 62.88 degrees respectively correspond to crystal faces (100), (002), (101), (102), (110) and (103) of ZnO. The diffraction peak of ZnO gradually decreased with the increase of hydrothermal reaction time due to MoS₂Compared with ZnO, the material has small size, so that only weak diffraction peaks of 32.68 degrees and 58.33 degrees can be detected, and the diffraction peaks correspond to hexagonal phase MoS₂The (100) and (110) crystal planes of (A).

FIG. 3 shows CC/ZnO/MoS samples₂The absorption curve of the methylene blue solution with the photocatalytic degradation concentration of 40ppm increases along with time, and the absorption of the methylene blue solution at 664nm gradually decreases.

FIG. 4 shows CC/ZnO/MoS samples₂And (4) carrying out optical photo in the process of degrading the methylene blue solution for-6 h, wherein the solution is transparent after 60min of degradation.

FIG. 5 is a graph of photocatalytic degradation of methylene blue solution for different samples. As can be seen from the figure, with MoS₂The photocatalytic efficiency of the composite material is gradually increased by increasing the growth time. When MoS is present in the sample₂The photocatalytic degradation efficiency is highest when the growth time of the catalyst is 6 hours, and within 60 minutes, the photocatalytic efficiency of degrading 40ppm methylene blue solution reaches 97.86 percent and the degradation is almost complete. This is because of the MoS in the 1h and 3h samples₂The amount of (A) is insufficient, and the utilization rate of light is low, thereby reducing the photocatalytic efficiency. MoS when the time increases to 9h₂Excessive amount of (2) excessive MoS₂Is covered with ZnO/MoS₂Of the interface of (a) so that light in the composite materialThe charge carriers are not effectively separated, which leads to a decrease in photocatalytic efficiency.

FIG. 6 shows a sample CC/ZnO/MoS under simulated sunlight irradiation₂-6h photocatalytic degradation mechanism diagram. When CC/ZnO/MoS₂When the composite material is illuminated, ZnO and MoS₂Are excited to generate electron-hole pairs. CB potential E of ZnO_CBIs-0.30 eV, ratio MoS₂CB of_CBMore negative (-0.14eV), so in ZnO-MoS₂At the interface, electrons are transferred from CB to MoS of ZnO₂The CB of (1). Similarly, holes are transferred from VB to MoS of ZnO₂VB of (2). In addition, due to MoS₂Has a potential of electrons (-0.11eV) to O in CB of (A)₂/·O₂ ^-Is more positive than O than the standard potential (-0.33eV)₂/H₂O₂Is more negative (0.69eV), so that the transition to MoS is made₂Electrons on CB are unable to trap O₂Reduction to O₂ ^-But first with O₂And H⁺Reaction to form H₂O₂Finally, OH is formed. h is⁺And OH radicals are very reactive oxidizing species that degrade MB into degradation products.

Detailed Description

Example 1

Weighing 0.7437g Zn (NO)₃·6H₂Dissolving O and 0.35048g HMT (hexamethylenetetramine) in 50mL deionized water, magnetically stirring for 1h until the solution is completely dissolved, pouring the solution into a reaction kettle, then placing carbon cloth into the reaction kettle, sealing the reaction kettle, and then placing the reaction kettle into a vacuum drying oven at 100 ℃ for 12 h. And (3) after the reaction is finished and the carbon cloth is cooled, washing the carbon cloth for 3 times by using deionized water and ethanol respectively, and annealing the carbon cloth for 1 hour in a muffle furnace at the temperature of 450 ℃ to obtain the CC/ZnO nanorod.

Example 2

Weighing 1.24g of sodium molybdate dihydrate and 2.28g of thiourea, placing the sodium molybdate dihydrate and the thiourea in a beaker, then adding 35mL of deionized water respectively, carrying out magnetic stirring for 30min until the sodium molybdate dihydrate and the thiourea are completely dissolved, then pouring all the solution into a 50mL polytetrafluoroethylene reaction kettle, then placing carbon cloth with ZnO nanorods in the reaction kettle, finally sealing the reaction kettle, and placing the reaction kettle in an oven to keep the temperature of 200 ℃ for reaction for 1 h. The reaction is finishedAnd after the reaction kettle is naturally cooled to the room temperature, taking out the carbon cloth and thoroughly washing the carbon cloth by deionized water and ethanol. Obtaining a sample CC/ZnO/MoS₂-1。

Example 3

Weighing 1.24g of sodium molybdate dihydrate and 2.28g of thiourea, placing the sodium molybdate dihydrate and the thiourea in a beaker, then adding 35mL of deionized water respectively, carrying out magnetic stirring for 30min until the sodium molybdate dihydrate and the thiourea are completely dissolved, then pouring all the solution into a 50mL polytetrafluoroethylene reaction kettle, then placing carbon cloth with ZnO nanorods in the reaction kettle, finally sealing the reaction kettle, and placing the reaction kettle in an oven to keep the temperature of 200 ℃ for reaction for 3 h. After the reaction is finished, the reaction kettle is naturally cooled to room temperature, the carbon cloth is taken out and is thoroughly washed clean by deionized water and ethanol. Obtaining a sample CC/ZnO/MoS₂-3。

Example 4

Weighing 1.24g of sodium molybdate dihydrate and 2.28g of thiourea, placing the sodium molybdate dihydrate and the thiourea in a beaker, then adding 35mL of deionized water respectively, carrying out magnetic stirring for 30min until the sodium molybdate dihydrate and the thiourea are completely dissolved, then pouring all the solution into a 50mL polytetrafluoroethylene reaction kettle, then placing carbon cloth with ZnO nanorods in the reaction kettle, finally sealing the reaction kettle, and placing the reaction kettle in an oven to keep the temperature of 200 ℃ for reaction for 6 h. After the reaction is finished, the reaction kettle is naturally cooled to room temperature, the carbon cloth is taken out and is thoroughly washed clean by deionized water and ethanol. Obtaining a sample CC/ZnO/MoS₂-6。

Example 5

Weighing 1.24g of sodium molybdate dihydrate and 2.28g of thiourea, placing the sodium molybdate dihydrate and the thiourea in a beaker, then adding 35mL of deionized water respectively, carrying out magnetic stirring for 30min until the sodium molybdate dihydrate and the thiourea are completely dissolved, then pouring all the solution into a 50mL polytetrafluoroethylene reaction kettle, then placing carbon cloth with ZnO nanorods in the reaction kettle, finally sealing the reaction kettle, and placing the reaction kettle in an oven to keep the temperature of 200 ℃ for reaction for 9 h. After the reaction is finished, the reaction kettle is naturally cooled to room temperature, the carbon cloth is taken out and is thoroughly washed clean by deionized water and ethanol. Obtaining a sample CC/ZnO/MoS₂-9。