阅读说明：本技术 一种1T-MoS2 QDs@UiO-66复合光催化剂的制备方法及光催化性能研究 (1T-MoS2Preparation method of QDs @ UiO-66 composite photocatalyst and photocatalytic performance research ) 是由 何雯雯 狄婉婷 韩旭 于 2021-09-06 设计创作，主要内容包括：本发明涉及一种UiO-66复合光催化剂的制备方法及其应用。先通过水热法合成1T-MoS-(2)量子点；采用原位合成的方法在合成UiO-66时,加入1T-MoS-(2)量子点,使量子点附着在UiO-66表面,形成1T-MoS-(2) QDs@UiO-66复合光催化剂。在光催化反应时,1T-MoS-(2) QDs负载的UiO-66复合光催化剂对光生电子-空穴的分离起到了很强的促进作用,此外MoS-(2)量子点能够暴露更多的活性位点,从而提高UiO-66的光催化产氢效率。本发明1T-MoS-(2)量子点负载的UiO-66复合光催化剂制备方法简单,方便,成本低,可重复性好。(The invention relates to a preparation method and application of a UiO-66 composite photocatalyst. Firstly, 1T-MoS is synthesized by a hydrothermal method 2 Quantum dots; when the UiO-66 is synthesized by adopting an in-situ synthesis method, 1T-MoS is added 2 Quantum dots, wherein the quantum dots are attached to the surface of UiO-66 to form 1T-MoS 2 QDs @ UiO-66 composite photocatalyst. In the case of photocatalytic reactions, 1T-MoS 2 The QDs loaded UiO-66 composite photocatalyst plays a strong role in promoting the separation of photoelectron-hole, and MoS 2 Quantum dot can violentlyMore active sites are exposed, thereby improving the photocatalytic hydrogen production efficiency of UiO-66. 1T-MoS of the invention 2 The quantum dot loaded UiO-66 composite photocatalyst has the advantages of simple and convenient preparation method, low cost and good repeatability.)

1. 1T-MoS₂The preparation method of the QDs @ UiO-66 composite photocatalyst is characterized by comprising the following steps: firstly, preparing UiO-66: mixing terephthalic acid and ZrCl₄Dissolving the mixture in a mixed solution of 10 ml of DMF and 1.2 ml of acetic acid solution, performing ultrasonic dissolution to form a uniform mixed solution, putting the mixed solution into a polytetrafluoroethylene high-pressure reaction kettle, cooling the mixed solution at 120 ℃ for 24 hours, performing centrifugal washing, and performing vacuum drying to obtain UiO-66; II, preparing 1T-MoS₂QDs: adding NaMoO₄·2H₂Adding O into 30 ml of distilled water, and marking as a solution A; c₁₄H₁₄S₂Adding into 30 ml ethanol, recording as solution B, stirring for 30 min, adding solution B into solution A, stirring for 30 min to form suspension, placing the suspension into a polytetrafluoroethylene high-pressure reaction kettle, cooling, centrifuging, and freeze drying to obtain 1T-MoS₂QDs; thirdly, preparing 1T-MoS₂QDs @ UiO-66 composite photocatalyst: in the step oneAdding 1T-MoS into the precursor solution₂QDs, forming a uniform mixed solution, putting the mixed solution into a polytetrafluoroethylene high-pressure reaction kettle, carrying out centrifugal washing on a product at the temperature of 120 ℃ for 24 hours, and carrying out vacuum drying on the product to obtain 1T-MoS₂QDs @ UiO-66 composite photocatalyst.

2. The method of claim 1 for preparing a UiO-66 material, wherein: the centrifugation speed was 6000 rpm for 5 minutes.

3. The method of claim 1 for preparing a UiO-66 material, wherein: washing was carried out twice with DMF and once with methanol.

4. The method of claim 1 for preparing a UiO-66 material, wherein: the temperature of vacuum drying was 70 ℃ for 12 hours.

5. 1T-MoS according to claim 1₂The preparation method of QDs is characterized in that: after the reaction kettle is cooled, the black product is dispersed by deionized water.

6. 1T-MoS according to claim 1₂The preparation method of QDs is characterized in that: the centrifugal speed is 11000 rpm, the time is 60 minutes, and the supernatant after centrifugation is 1T-MoS after freeze drying₂ QDs。

Technical Field

The invention relates to preparation of a composite photocatalyst and photocatalytic performance research thereof.

Background

In the past decades, the world's energy consumption has increased exponentially, and atmospheric pollution and environmental destruction due to excessive use of fossil fuels are serious problems facing the world. The limited reserves and gradual depletion of fossil fuels have made energy production technologies essential on the basis of the development of renewable resources. Therefore, promoting the development of sustainable and energy-efficient chemical technologies is the most pressing challenge facing scientists today. The photocatalytic hydrogen production has wide application prospect in solving the problems of energy and environment, can effectively solve the problems of environmental pollution and energy shortage, can convert solar energy into hydrogen energy by the photocatalytic hydrogen production reaction, saves the steps of electricity generation and transmission compared with the step of utilizing secondary energy electric energy in an electro-catalytic system, has higher competitiveness in efficiency, and the composite photocatalyst of a metal-organic framework and a semiconductor attracts more attention in the aspect of photocatalysis.

Metal-organic framework Materials (MOFs), also known as porous coordination polymers, are generally organic-inorganic hybrid materials that are self-assembled from organic linkers and inorganic metal nodes. The MOFs material has the advantages of large specific surface area, high porosity, adjustable pore channel, easy functionalization and the like, and has potential application value in the fields of gas separation, photocatalysis, proton conductors, drug loading and the like. UiO-66 is one of Zr-based MOFs, which uses Zr ions as metal nodes, H₂BDC is a classical MOFs structure formed as an organic linker. The stable coordination bond between the metal and the ligand enables UiO-66 to have good mechanical, thermal and chemical stability, and enables the structure to have certain photoresponse capability, thus being a class of MOFs photocatalytic materials which are intensively researched.

MoS₂Mainly exists in nature in the form of molybdenite, and the appearance of the molybdenite is black powder. MoS₂Is a typical n-type semiconductor material, has a layered structure similar to graphene, and a metal Mo atomic layer is sandwiched by two S atomic layers, and has a typical structure (S-Mo-S) similar to a sandwich structure. MoS₂The structure of (A) is nano particles, nano spheres, nano flowers, quantum dots and the like, wherein the MoS has zero dimension₂Due to the unique quantum effect characteristics of the quantum dots, the electron-hole separation of photoelectrons can be promoted, and the photocatalytic activity is effectively improved. MoS₂QDs have 1T-MoS₂ QDs，2H-MoS₂ QDs，3R-MoS₂Three different phases of QDs. Compared with 2H-MoS₂QDs and 3R-MoS₂ QDs，1T-MoS₂QDs have higher conductivity and can increase electricity more effectivelyCharge transfer between the children. MoS₂QDs rapidly become a research hotspot in the catalysis field due to the unique electronic band structure and high catalytic activity thereof, and have great application potential in the aspects of photocatalytic hydrogen production, photocatalytic pollutant degradation and the like.

Disclosure of Invention

The invention aims to synthesize 1T-MoS₂QDs @ UiO-66 composite photocatalyst, 1T-MoS₂QDs are attached to the surface of UiO-66, and the photocatalytic hydrogen production performance is improved.

1T-MoS of the invention₂The preparation method of the QDs @ UiO-66 composite photocatalyst is characterized by comprising the following steps of:

firstly, preparing UiO-66: mixing terephthalic acid and ZrCl₄Dissolving the mixture in a mixed solution of 10 ml of DMF and 1.2 ml of acetic acid solution, performing ultrasonic dissolution to form a uniform mixed solution, and putting the mixed solution into a polytetrafluoroethylene high-pressure reaction kettle at the temperature of 120 ℃ for 24 hours. After cooling, the product was washed by centrifugation and dried in vacuo to give UiO-66.

II, preparing 1T-MoS₂QDs: adding NaMoO₄·2H₂Adding O into 30 ml of distilled water, and marking as a solution A; c₁₄H₁₄S₂The mixture was added to 30 ml of ethanol, designated as solution B, and stirred for 30 minutes, and then solution B was added to solution A and stirred for 30 minutes to form a suspension. And (3) putting the obtained suspension into a polytetrafluoroethylene high-pressure reaction kettle, and keeping the temperature at 180 ℃ for 20 hours. After cooling, the reaction product is centrifuged and freeze-dried to obtain 1T-MoS₂ QDs。

Thirdly, preparing 1T-MoS₂QDs @ UiO-66 composite photocatalyst: adding MoS into the precursor solution in the step one₂QDs, forming a homogeneous mixed solution, and placing the solution into a polytetrafluoroethylene high-pressure reaction kettle at the temperature of 120 ℃ for 24 hours. The product is centrifugally washed and dried in vacuum to obtain 1T-MoS₂QDs @ UiO-66 composite photocatalyst.

Further, the centrifugation speed of step one was 6000 rpm for 5 minutes.

Further, in the first washing step, DMF is used for washing twice, and methanol is used for washing once.

Further, the temperature of the vacuum drying in the first step is 70 ℃ for 12 hours.

And further, after the reaction kettle in the second step is cooled, dispersing a black product by deionized water.

Further, the centrifugal speed in the second step is 11000 rpm, the time is 60 minutes, and the supernatant after centrifugation is 1T-MoS₂QDs。

The invention has the advantages that:

(1) the composite photocatalyst synthesized by the invention is composed of 1T-MoS₂QDs and UiO-66 are formed by compounding, and compared with single UiO-66, the catalyst has higher photocatalytic hydrogen production performance.

(2) The invention adopts one-step hydrothermal synthesis and has simple operation. The quantum dots have small size and can convert MoS into MoS₂QDs are attached to the surface of UiO-66, and can ensure the integrity of the structure of UiO-66, increase the number of active sites of the catalyst and the capability of electron transfer, and improve the photocatalytic hydrogen production performance of the catalyst.

Drawings

FIG. 1 shows UiO-66 and 1T-MoS₂PXRD pattern of QDs @ UiO-66.

FIG. 2 shows UiO-66 and 1T-MoS₂Energy spectra (EDS) of QDs @ UiO-66.

FIG. 3 shows UiO-66 and 1T-MoS₂QDs @ UiO-66.

FIG. 4 shows UiO-66 and 1T-MoS₂Electrochemical impedance plot (EIS) of QDs @ UiO-66.

FIG. 5 is an infrared spectrum (FT-IR) of 1T-MoS2 QDs @ UiO-66 before and after the photocatalysis.

Detailed Description

To further clarify the disclosure, features, and advantages of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings.

Example 1

1T-MoS of the present example₂The preparation method of the QDs @ UiO-66 photocatalytic complexing agent comprises the following steps:

the method comprises the following steps: the preparation method of UiO-66 comprises the following steps: 10.1956 mg of terephthalic acid, 6.65 mg of ZrCl₄Dissolving the mixture in a mixed solution of 10 ml of DMF and 1.2 ml of acetic acid solution, performing ultrasonic dissolution to form a uniform mixed solution, and putting the mixed solution into a polytetrafluoroethylene high-pressure reaction kettle at the temperature of 120 ℃ for 24 hours. After cooling to room temperature, the resulting suspension was washed centrifugally, 2 times with DMF and 1 time with methanol. The rotation speed was 6000 rpm for 5 minutes. And (3) carrying out vacuum drying on the white solid obtained by centrifugation at 70 ℃ for 12 hours to obtain UiO-66.

Step two: preparation of 1T-MoS₂QDs: 0.4 g of NaMoO₄·2H₂Adding O into 30 ml of distilled water, and marking as a solution A; 0.38 g C₁₄H₁₄S₂The mixture was added to 30 ml of ethanol, designated as solution B, and stirred for 30 minutes, and then solution B was added to solution A and stirred for 30 minutes to form a suspension. And (3) putting the obtained suspension into a polytetrafluoroethylene high-pressure reaction kettle, and keeping the temperature at 180 ℃ for 20 hours. Cooling to room temperature, pouring out the light yellow supernatant, separating black product with 30 ml deionized water, centrifuging at 11000 rpm for 60 min to obtain supernatant, and freeze drying to obtain 1T-MoS₂ QDs。

Step three: 1T-MoS₂The preparation method of the QDs @ UiO-66 composite photocatalyst comprises the following steps: 5 mg of MoS₂QDs, 10.1956 mg terephthalic acid, 6.65 mg ZrCl₄Dissolving the mixture in a mixed solution of 10 ml of DMF and 1.2 ml of acetic acid solution, performing ultrasonic dissolution to form a uniform mixed solution, and putting the mixed solution into a polytetrafluoroethylene high-pressure reaction kettle at the temperature of 120 ℃ for 24 hours. After cooling to room temperature, the resulting suspension was washed centrifugally, 2 times with DMF and 1 time with methanol. The rotation speed was 6000 rpm for 5 minutes. The yellow solid obtained by centrifugation is dried in vacuum at 70 ℃ for 12 hours to obtain 1T-MoS₂QDs @ UiO-66 composites.

Example 2

1T-MoS of the present example₂The preparation method of the QDs @ UiO-66 composite material comprises the following steps:

step (ii) together with step (ii) in embodiment 1

Step two is the same as step two in embodiment 1

Step three: 1T-MoS₂QDs @ UiO-66 composite photocatalysisThe preparation method of the agent comprises the following steps: 3 mg of MoS₂QDs, 10.1956 mg terephthalic acid, 6.65 mg ZrCl₄Dissolving the mixture in a mixed solution of 10 ml of DMF and 1.2 ml of acetic acid solution, performing ultrasonic dissolution to form a uniform mixed solution, and putting the mixed solution into a polytetrafluoroethylene high-pressure reaction kettle at the temperature of 120 ℃ for 24 hours. After cooling to room temperature, the resulting suspension was washed centrifugally, 2 times with DMF and 1 time with methanol. The rotation speed was 6000 rpm for 5 minutes. Centrifuging to obtain yellow solid, and vacuum drying at 70 deg.C for 12 hr to obtain 1T-MoS₂ [email protected]。

Example 3

1T-MoS of the present example₂The preparation method of the QDs @ UiO-66 composite photocatalyst comprises the following steps:

step (ii) together with step (ii) in embodiment 1

Step two is the same as step two in embodiment 1

Step three: 1T-MoS₂The preparation method of the QDs @ UiO-66 composite photocatalyst comprises the following steps: 7 mg of MoS₂QDs, 10.1956 mg terephthalic acid, 6.65 mg ZrCl₄Dissolving the mixture in a mixed solution of 10 ml of DMF and 1.2 ml of acetic acid solution, performing ultrasonic dissolution to form a uniform mixed solution, and putting the mixed solution into a polytetrafluoroethylene high-pressure reaction kettle at the temperature of 120 ℃ for 24 hours. After cooling to room temperature, the resulting suspension was washed centrifugally, 2 times with DMF and 1 time with methanol. The rotation speed was 6000 rpm for 5 minutes. Centrifuging to obtain yellow solid, vacuum drying at 70 deg.C for 12 hr to obtain 1T-MoS₂QDs @ UiO-66 composite photocatalyst.

Sample characterization and Performance testing

FIG. 1 shows specific examples 1 step one prepared UiO-66 and step three prepared 1T-MoS₂XRD pattern of QDs @ UiO-66, the results showed that the synthesis of UiO-66 was successful and 1T-MoS₂The XRD of QDs @ UiO-66 was consistent with that of UiO-66XRD, indicating 1T-MoS₂The loading of QDs does not change the UiO-66 structure.

FIG. 2 shows specific example 1, step one prepared UiO-66 and step three prepared 1T-MoS₂Energy spectrum (EDS) of QDs @ UiO-66, the result of which indicates the presence of the composite materialZr, C, O, N, Mo, S, indicating 1T-MoS₂QDs are successfully loaded on the UiO-66 surface.

FIG. 3 shows specific example 1, step one prepared UiO-66 and step three prepared 1T-MoS₂Photo-catalytic hydrogen production diagram of QDs @ UiO-66, the result shows, 1T-MoS₂The photocatalytic hydrogen production of QDs @ UiO-66 is 263 mu mol g^-1Compared with UiO-66, the photocatalytic hydrogen production performance is greatly improved.

FIG. 4 shows specific example 1, step one prepared UiO-66 and step three prepared 1T-MoS₂Electrochemical impedance mapping (EIS) of QDs @ UiO-66, results show 1T-MoS₂The radius of the QDs @ UiO-66 composite photocatalyst arc is smaller than that of UiO-66, which indicates that the charge transfer of the composite material is faster.

FIG. 5 example 1 preparation of 1T-MoS in step three₂The infrared spectrograms (FT-IR) before and after the photocatalytic reaction of QDs @ UiO-66 show that the spectrograms before and after the photocatalytic reaction have no obvious change, which indicates that the composite material has good stability in the photocatalytic reaction.