CN115430463B - MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst and preparation method and application thereof - Google Patents
MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst and preparation method and application thereof Download PDFInfo
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Abstract
The invention discloses a MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst, a preparation method and application thereof. The preparation method comprises the following steps: step S1: carrying out ultrasonic stripping on the molybdenite concentrate to obtain a molybdenite quantum dot solution; step S2: preparing MOFs material; step S3: MOFs material; mixing with molybdenite quantum dot solution, stirring, filtering, collecting, and oven drying; step S4: adding MOFs/molybdenite quantum dot binary compound and cadmium salt into an organic solvent according to a proportion to be fully dissolved, and dissolving a proper amount of sulfur-containing compound into the organic solvent; and (3) dropwise adding the dissolved sulfur-containing compound into the mixed solution of the binary composite product and the cadmium salt, stirring, performing hydrothermal treatment, cooling, washing the product with ethanol, and drying. The ternary heterojunction catalyst prepared by the invention has high catalytic activity, and the highest performance reaches 10000 mu molh ‑1 g ‑1 And has good stability under illumination.
Description
Technical Field
The invention relates to the technical field of catalysts, in particular to a MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst, a preparation method and application thereof.
Background
At present, electrolysis of water is the most dominant hydrogen production technology, however, this approach is more costly. The photocatalytic water splitting to generate hydrogen is a simple and easy technology with wide prospect, thereby attracting important attention.
Cadmium sulfide has excellent visible light response capability and good energy band structure, which causes a great deal of research, however, pure CdS is easy to corrode under visible light, unstable in aqueous solution, and easy to polymerize, so that catalytic sites are reduced and carrier recombination is fast, which greatly limits the application of pure CdS in hydrogen production. Therefore, how to obtain a stable and efficient catalyst is the direction of current research.
Disclosure of Invention
The invention aims at providing a MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst, a preparation method and application thereof, aiming at the defects of the prior art.
The preparation method of the MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst comprises the following steps:
step S1: carrying out ultrasonic stripping on the molybdenite concentrate to obtain a molybdenite quantum dot solution;
step S2: preparation of MOFs Material NH 2 -MIL-125(Ti)；
Step S3: MOFs material NH 2 Mixing MIL-125 (Ti) with the molybdenite quantum dot solution, filtering the product, collecting and drying to obtain MOFs/molybdenite quantum dot binary compound;
step S4: adding MOFs/molybdenite quantum dot binary compound and cadmium salt into an organic solvent according to a proportion to be fully dissolved, and dissolving a proper amount of sulfur-containing compound into the organic solvent; dropwise adding the dissolved sulfur-containing compound into a mixed solution of the binary composite product and cadmium salt, stirring, performing hydrothermal treatment, cooling, cleaning the product with ethanol, and finally drying to obtain the MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst;
wherein, steps S1 and S2 are not sequential.
In step S3, the mass ratio of MOFs to molybdenite quantum dots is 100:2-8.
In the step S4, cadmium salt is cadmium chloride, and the mass ratio of the MOFs/molybdenite quantum dot binary compound to the cadmium salt is 1-3:3-1.
In step S4, the sulfur-containing compound is sodium sulfide nonahydrate, the organic solvent is a mixed solution of glycerol and ethanol, and the mass ratio of the sulfur-containing compound to cadmium salt is 1-10:1.
Further, in the step S4, the water is heated for 6-12 hours at the temperature of 80-120 ℃.
Further, the specific operation in step S1 is as follows: adding molybdenite concentrate powder into a certain ethanol solution, placing the ethanol solution into an ultrasonic extractor for 1200W ultrasonic treatment for 6-12h, centrifuging the ultrasonic solution, and collecting supernatant to obtain the molybdenite quantum dot solution.
Further, the solution after the ultrasonic treatment is centrifuged at 8000-10000rpm for 5min.
Further, the specific operation of step S2 is as follows: sequentially adding 2-amino terephthalic acid, N-dimethylformamide and methanol into a reaction kettle, dropwise adding tetrabutyl titanate into the reaction kettle, stirring for a period of time, heating the reaction temperature to 150 ℃, cooling to room temperature after the reaction for a period of time, filtering, washing and vacuum drying the product to obtain MOFs material NH 2 -MIL-125(Ti)。
MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst prepared by adopting the preparation method.
The MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst is used as a photocatalyst to catalyze water to produce hydrogen under visible light.
The invention adopts MOFs material NH 2 MIL-125 (Ti) as substrate, NH 2 MIL-125 (Ti) has higher stability and porosity, a large amount of Ti-oxo clusters, and can be used as a perfect medium for photo-generated electrons in a photo-catalytic reaction.
The MOFs energy band structure adopted in the invention is adjustable, and is easy to functionalize; the preparation of the molybdenite quantum dots utilizes ultrasonic stripping, and the scheme is simple and easy to implement; meanwhile, for the preparation of the ternary heterojunction, the hydrothermal reaction is carried out for 6-12 hours at the temperature of 80-120 ℃, the time consumption is short, and the prepared material is excellent in performance and good in stability.
The invention provides a simpleMOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst prepared by solvothermal method with low cost and low temperature has high catalytic activity and highest performance of 10000 mu molh -1 g -1 And the stability under illumination is good, and the preparation method is simple and easy to implement.
Drawings
FIG. 1 is an X-ray powder diffraction pattern of a MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst prepared in example 9;
FIG. 2 is a scanning electron microscope image of MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst prepared in example 9;
FIG. 3 is an ultraviolet visible diffuse reflectance spectrum of a MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst prepared in example 9;
FIG. 4 is a graph of photocatalytic hydrogen production rate under visible light for MOFs/molybdenite quantum dot/CdS ternary heterojunction catalysts prepared in example 9;
FIG. 5 is a graph of the stability of MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst prepared in example 9 under visible light;
FIG. 6a is an X-ray photoelectron spectrum of a MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst prepared in example 9;
FIG. 6b XPS spectrum of Cd element;
an XPS profile of element c O of fig. 6;
figure 7 electrochemical impedance plot of MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst prepared in example 9.
FIG. 8 is a graph of transient photocurrent response of MOFs/molybdenite quantum dot/CdS ternary heterojunction catalysts prepared in example 9.
Detailed Description
The following are specific embodiments of the present invention and the technical solutions of the present invention will be further described with reference to the accompanying drawings, but the present invention is not limited to these embodiments.
Example 1: NH of the present embodiment 2 The preparation method of the MIL-125 (Ti) loaded molybdenite quantum dot and CdS photocatalyst is completed according to the following steps:
firstly, grinding 5g of natural molybdenite into ore pulp (74 mu m) by using water balls, transferring the ore pulp into a flotation tank, and adding 40mg/L diesel oil and 30mg/L pine oil as a collector and a foaming agent. And generating flotation foam after aeration, and collecting the flotation foam as rough molybdenum concentrate. The crude molybdenum concentrate was then regrind to 38 μm (200 mesh) and, after ball milling, transferred to a flotation cell for cleaning operations. Then, 500mg/L sodium thioglycolate and 350mg/L fosinox were added as inhibitors. And (3) stirring, aerating, collecting concentrated foam, and performing the next cleaning operation, wherein the dosage of the reagent is half of that of the previous step. After seven cleaning operations, the final concentrate foam was collected and dried to obtain 1.2g of molybdenite powder. 100mg of molybdenite powder is added into 250mL of ethanol solution, the mixture is put into an ultrasonic extractor for ultrasonic treatment of 1200W for 6 hours, and then the ultrasonic treated solution is subjected to centrifugal treatment at 8000rpm for 5 minutes, and supernatant fluid is collected, so that the molybdenite quantum dot solution is obtained.
Step two, firstly, 2.2g of 2-amino terephthalic acid is weighed by an electronic balance and added into a reaction kettle with the size specification of 100mL, then 36mL of N, N-Dimethylformamide (DMF) and 4mL of methanol are weighed by a liquid-transfering gun and added into the reaction kettle, next, 2.4mL of tetrabutyl titanate is weighed, tetrabutyl titanate is dropwise added into the reaction kettle, and after stirring for 30 minutes, the solvent is heated at 150 ℃ for 48 hours. After the reaction kettle is cooled to room temperature, the product is washed by DMF and methanol for three times, and then is dried in vacuum at 150 ℃ for 12 hours to obtain NH2-MIL-125 (Ti).
Step three, at 100mgNH 2 Adding 2-8mg of the molybdenite quantum dot solution of the molybdenite quantum dot in the first step into MIL-125 (Ti), adding the solution to 100mL, stirring at 25 ℃ for 12 hours, carrying out suction filtration to obtain a solid product, and drying at 60 ℃ for 8 hours to obtain the MOFs/molybdenite quantum dot binary compound.
And step four, adding 50mg of MOFs/molybdenite quantum dot binary compound with the best performance and 65mg of cadmium chloride obtained in the step three into 25mL of mixed solution of glycerol and ethanol (1:5), completely dissolving the MOFs/molybdenite quantum dot binary compound and the cadmium chloride under ultrasonic conditions, adding 85mg of sodium sulfide nonahydrate into 25mL of mixed solution of glycerol and ethanol (1:5), completely dissolving the sodium sulfide nonahydrate under ultrasonic conditions, dropwise adding the sodium sulfide nonahydrate solution into the mixed solution of binary composite product and cadmium chloride, stirring for 30min, then carrying out hydrothermal treatment at 100 ℃ for 6h, finally washing a sample with ethanol three times, centrifuging at 8000rpm, and drying at 60 ℃ for 2h to obtain the ternary heterojunction catalyst.
Example 2: this embodiment differs from example 1 in that: in the first step, 100mg of molybdenite powder is added into 250mL of ethanol solution, and the mixture is put into an ultrasonic extractor for ultrasonic treatment of 1200W for 8 hours. Other steps were consistent with example 1.
Example 3: this embodiment differs from example 1 in that: in the first step, 100mg of molybdenite powder is added into 250mL of ethanol solution, and the mixture is put into an ultrasonic extractor for 10 hours under 1200W ultrasonic treatment. Other steps were consistent with example 1.
Example 4: this embodiment differs from example 1 in that: in the first step, 100mg of molybdenite powder is added into 250mL of ethanol solution, and the mixture is put into an ultrasonic extractor for 12 hours under 1200W ultrasonic treatment. Other steps were consistent with example 1.
Example 5: this embodiment differs from example 1 in that: and (3) centrifuging the solution after ultrasonic treatment for 5min, wherein the centrifugal speed is 9000rpm. Other steps were consistent with example 1.
Example 6: this embodiment differs from example 1 in that: and (3) centrifuging the solution after ultrasonic treatment for 5min, wherein the centrifugal speed is 10000rpm. Other steps were consistent with example 1.
Example 7: this embodiment differs from example 1 in that: stirring NH as described in step three 2 The temperature of the MIL-125 (Ti) and molybdenite quantum dot solution 12h was 40 ℃. Other steps were consistent with example 1.
Example 8: this embodiment differs from example 1 in that: stirring NH as described in step three 2 The temperature of the MIL-125 (Ti) and molybdenite quantum dot solution 12h was 60 ℃. Other steps were consistent with example 1.
Example 9: this embodiment differs from example 1 in that: the mass of the sodium sulfide nonahydrate added in the step four is 225mg. Other steps were consistent with example 1.
Example 10: this embodiment differs from example 1 in that: the mass of the sodium sulfide nonahydrate added in the step four is 425mg. Other steps were consistent with example 1.
Example 11: this embodiment differs from example 1 in that: the mass of the sodium sulfide nonahydrate added in the fourth step is 850mg. Other steps were consistent with example 1.
Example 12: this embodiment differs from example 1 in that: the temperature of the hydrothermal reaction in the fourth step is 80 ℃. Other steps were consistent with example 1.
Example 13: this embodiment differs from example 1 in that: the temperature of the hydrothermal reaction in the fourth step is 120 ℃. Other steps were consistent with example 1.
Example 14: the embodiment differs from example 1 in that: the hydrothermal reaction time in the fourth step is 12h. Other steps were consistent with example 1.
Example 15: the embodiment differs from example 1 in that: the hydrothermal reaction time in the fourth step is 18h. Other steps were consistent with example 1.
The hydrogen production performance of the catalyst under the visible light is studied in a 100mL double-ear reactor, and the reaction is in a normal-temperature vacuum state. The reaction light source is a 300W xenon lamp, ultraviolet light below 420nm is filtered out through a 420nm cut-off filter, and the outlet of the light source is 15cm away from the reaction liquid level. In preparation of the reaction solution, the catalyst (5 mg) was first ultrasonically dispersed in 50mL of an aqueous solution containing 10vol% lactic acid, then 1wt% chloroplatinic acid solution was added, and then the reaction system was evacuated to remove oxygen and interfering gases in the system, and then irradiated with light for 30 minutes to deposit platinum on the catalyst surface. Then, the reaction was carried out under light for 5 hours, and during the reaction, the amount of hydrogen gas produced per hour was detected using Fu Li gas chromatography.
The structural characterization method of MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst comprises taking Cu target Ka as X-ray source, and scanning at a rate of 5 deg. s -1 The phases and structures were characterized on an X-ray diffractometer. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) were used to observe the morphology, structure and particle size of the catalyst. Applying ultraviolet-visible spectrophotometer to light of sampleThe absorption capacity was characterized.
Fig. 1 is an X-ray powder diffraction pattern of the photocatalyst prepared in example 9, with three peaks observed at 14.1 °, 44.3 ° and 58.9 ° for a single molybdenite concentrate. The two can be well matched through comparison with a standard card. For a single NH 2 MIL-125 (Ti), characteristic peaks of 10 DEG, 5.6 DEG, 12.5 DEG, 16.8 DEG, 18.3 DEG and 22.5 DEG respectively correspond to (101), (002), (211), (222), (312) and (004) crystal planes, indicating NH 2 MIL-125 (Ti) synthesis was successful. For CdS, there are characteristic peaks at 26.5 °, 44.0 °, 52.1 °, 54.6 °, perfectly matching with cubic CdS. And these characteristic peaks correspond to the (111), (220), (311), (222) crystal planes, respectively. And further analysis of the ternary material can find that for MOFs/molybdenite quantum dots/CdS, three independent characteristic peaks exist, which proves that the MOFs/molybdenite quantum dots/CdS are successfully prepared.
FIG. 2 is a Scanning Electron Microscope (SEM) spectrum of the photocatalyst prepared in example 9, wherein a, b, and c are each a single material NH 2 -MIL-125 (Ti), molybdenite quantum dots, cdS, d is MOFs/molybdenite quantum dot binary composite, and e is MOFs/molybdenite quantum dots/CdS. By observing the morphology of the sample, it can be seen from FIG. 2a that a single NH 2 MIL-125 (Ti) is mostly in the form of a block with a lateral dimension ranging between 500 and 1000nm, except for a small portion which assumes the shape of a disk. It can be seen from fig. 2b that the single molybdenite quantum dots are flake-shaped, have a lateral size ranging between 300-800nm, and have a remarkable stacking phenomenon because stacking is inevitably generated during the sample preparation process. It can be seen from FIG. 2c that the single CdS appears to be particulate-like and aggregated together. Further analysis of the composite material, NH can be seen in FIG. 2d 2 The surface of MIL-125 (Ti) has some flaky molybdenite quantum dots, and the close contact effect can inhibit the recombination of electron holes and promote NH 2 MIL-125 (Ti) performance. Of course, the coverage is not significant enough due to the small amount of molybdenite quantum dots introduced. FIG. 2e is a graph of the morphology of MOFs/molybdenite quantum dots/CdS, which is seen to be similar to FIG. 2cNH is added due to the fact that CdS is introduced more 2 MIL-125 (Ti) encases.
FIG. 3 is a solid ultraviolet-visible diffuse reflectance spectrum of the photocatalyst prepared in example 9. The left side is a spectrogram of the binary composite material with different molybdenite quantum dot contents, and it can be seen that the response capability of the binary composite material in the visible light region is enhanced along with the increase of the molybdenite quantum dot contents. On the right is the spectral diagram of the best performing catalyst, from which it can be seen that the ternary heterojunction is relative to NH alone 2 The visible light response capability of MIL-125 (Ti), molybdenite quantum dots and CdS components is obviously improved.
Fig. 4 is a graph showing the photocatalytic hydrogen production performance of the photocatalyst prepared in example 9 under visible light. The left side is a photocatalysis hydrogen production performance graph of binary composite materials with different molybdenite quantum dot contents, and can be seen that a single NH 2 MIL-125 (Ti) and molybdenite quantum dots do not have catalytic properties, however, NH 2 The composite MIL-125 (Ti) and molybdenite quantum dots have photocatalysis performance, and the molybdenite quantum dots with different contents load NH 2 The sequence of the photocatalytic hydrogen production activity of MIL-125 (Ti) is as follows: 6wt%>8wt％>4wt％>2wt%; the right side is the spectrum diagram of the catalyst with the best performance, and the single MOFs/molybdenite quantum dot binary composite material is still low in performance, but after CdS is loaded, the performance of the catalyst is obviously improved, and the best performance reaches 10000 mu molh -1 g -1 。
FIG. 5 is a wavelength spectrum of a ternary heterojunction catalyst prepared in example 9>Stability evaluation graph at 420nm incident light. As shown in fig. 4, the stability test is at wavelength>420nm, optical power of 300mW/cm 2 Is carried out under illumination without secondary addition of sacrificial agent within 20 hours, the reaction takes 5 hours as one reaction period. In a total stability test of 20 hours, it is verified that the ternary heterojunction composite photocatalyst has good stability. As can be seen from the graph, the reaction rate of the first three reaction cycles is approximately the same, even at gradual increase, and the reaction rate of the latter cycle is slightly reduced compared with the first three cycles, possibly due to oxidation of the sacrificial agentThe reduction in the sacrificial dose slightly reduces performance.
FIG. 6 is an X-ray photoelectron spectrum of the photocatalyst prepared in example 9. From FIG. 6a, it can be seen that NH 2 MIL-125 (Ti) contains C, ti, N, O elements, and MOFs/molybdenite quantum dots/CdS contains C, ti, N, O, cd, S elements. FIG. 6b is an XPS spectrum of Cd element, with two peaks at 404.83eV and 411.47eV belonging to 3d of Cd 5/2 And 3d 3/2 After the CdS is combined with MOFs/molybdenite quantum dots to form a ternary composite, the positions of the two peaks of Cd are shifted to high binding energy positions. This is because when CdS is combined with MOFs/molybdenite quantum dots, the empty orbitals of Cd coordinate with the lone pair electrons of O, and electrons are shifted from O with high density to Cd, so that the binding energy of Cd increases. FIG. 6c is an XPS spectrum of O element when O is NH 2 In MILs-125 (Ti), the peaks at three positions 532.64eV, 531.90eV and 530.40eV represent c=o bonds, C-O bonds and bound water, respectively, whereas after the ternary composite is formed, the bound water peak disappears, the peak representing o=cd bonds at 530.20eV is increased, and at the same time the peaks belonging to c=o bonds and C-O bonds start to move towards a low binding energy, indicating that after Cd and O form coordination bonds, a part of electrons will be transferred towards Cd, the charge density around Cd increases and the charge density of c=o bonds and C-O bonds decreases, and the binding energy decreases. The above changes also confirm the success of the synthesis of the material from the side, and the interaction between MOFs/molybdenite quantum dots and CdS is formed, so that a ternary heterojunction is constructed.
FIG. 7 is a graph showing the results of electrochemical impedance testing of the photocatalyst prepared in example 9. The action of catalyst carriers is researched by measuring the electrochemical impedance of a material, and the smaller the semicircle radius on the electrochemical impedance spectrum is, the smaller the impedance representing the catalyst is, and the higher the charge transfer and separation efficiency of the catalyst can be proved. As can be seen from the figure, represents NH 2 The curve of MIL-125 (Ti) has the largest semi-circle radius, the semi-circle radius of MOFs/molybdenite quantum dots is the second time, and the semi-circle radius of MOFs/molybdenite quantum dots/CdS is the smallest, which indicates NH 2 After MIL-125 (Ti) is compounded with molybdenite quantum dots, the carrier separation efficiency is improved, and after CdS is compounded, the carrier separation efficiency is obtainedA significant improvement, consistent with the results of the performance test.
FIG. 8 is a graph of transient photocurrent response of the preparation of example 9, under conditions simulating photocatalysis, and a test was performed by placing a glassy carbon electrode prepared with a catalyst in an aqueous solution containing 10vol% lactic acid, with a bias voltage set at 0.5V, and illumination time and interval at 50s. Under the same bias and illumination, the greater the photocurrent of the material, the higher the carrier separation efficiency representing the surface of the material. As can be seen from the graph, the order of photocurrent intensity is MOFs/molybdenite quantum dots/CdS>CdS>MOFs/molybdenite quantum dots>NH 2 MILs-125 (Ti), consistent with the results of electrochemical impedance and performance tests.
The above is not relevant and is applicable to the prior art.
While certain specific embodiments of the present invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the foregoing examples are provided for the purpose of illustration only and are not intended to limit the scope of the invention, and that various modifications or additions and substitutions to the described specific embodiments may be made by those skilled in the art without departing from the scope of the invention or exceeding the scope of the invention as defined in the accompanying claims. It should be understood by those skilled in the art that any modification, equivalent substitution, improvement, etc. made to the above embodiments according to the technical substance of the present invention should be included in the scope of protection of the present invention.
Claims (9)
1. A preparation method of MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst is characterized by comprising the following steps: the method comprises the following steps:
step S1: carrying out ultrasonic stripping on the molybdenite concentrate to obtain a molybdenite quantum dot solution;
step S2: preparation of MOFs Material NH 2 -MIL-125(Ti)；
Step S3: MOFs material NH 2 Mixing MIL-125 (Ti) with the molybdenite quantum dot solution, filtering the product, collecting and drying to obtain MOFs/molybdenite quantum dot binary compound;
step S4: adding MOFs/molybdenite quantum dot binary compound and cadmium salt into an organic solvent according to a proportion to be fully dissolved, and dissolving a proper amount of sulfur-containing compound into the organic solvent; dropwise adding the dissolved sulfur-containing compound into a mixed solution of the binary composite product and cadmium salt, stirring, performing hydrothermal treatment, cooling, cleaning the product with ethanol, and finally drying to obtain the MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst; in the step S4, the water heating is carried out at 80-120 ℃ and is 6-12 h;
wherein, steps S1 and S2 are not sequential.
2. The method for preparing the MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst according to claim 1, which is characterized by comprising the following steps: in the step S3, the mass ratio of MOFs to molybdenite quantum dots is 100:2-8.
3. The method for preparing the MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst according to claim 1, which is characterized by comprising the following steps: in the step S4, the cadmium salt is cadmium chloride, and the mass ratio of the MOFs/molybdenite quantum dot binary compound to the cadmium salt is 1-3:3-1.
4. The method for preparing the MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst according to claim 1, which is characterized by comprising the following steps: in the step S4, the sulfur-containing compound is sodium sulfide nonahydrate, the organic solvent is a mixed solution of glycerol and ethanol, and the mass ratio of the sulfur-containing compound to cadmium salt is 1-10:1.
5. The method for preparing the MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst according to claim 1, which is characterized by comprising the following steps: the specific operation in step S1 is: adding molybdenite concentrate powder into a certain ethanol solution, placing the ethanol solution into an ultrasonic extractor for 1200-W ultrasonic treatment of 6-12h, centrifuging the ultrasonic solution, and collecting supernatant to obtain the molybdenite quantum dot solution.
6. The method for preparing the MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst according to claim 5, wherein the method comprises the following steps of: centrifuging the solution after ultrasonic treatment at 8000-10000rpm for 5min.
7. The method for preparing the MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst according to claim 1, which is characterized by comprising the following steps: the specific operation of step S2 is as follows: sequentially adding 2-amino terephthalic acid, N-dimethylformamide and methanol into a reaction kettle, dropwise adding tetrabutyl titanate into the reaction kettle, stirring for a period of time, heating the reaction temperature to 150 ℃, cooling to room temperature after the reaction for a period of time, filtering and washing the product, and vacuum drying to obtain MOFs material NH 2 -MIL-125(Ti)。
8. A MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst prepared by the preparation method of any one of claims 1-7.
9. The use of the MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst of claim 8, wherein: the MOFs/molybdenite quantum dot/CdS ternary heterojunction catalyst is used as a photocatalyst to catalyze water to produce hydrogen under visible light.
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