Photocatalyst based on CdS / UiO-67 in-situ reconstruction and preparation method and application thereof
By preparing a defective UiO-67 support and loading CdS and trace amounts of Pt cocatalyst, the problem of high photogenerated electron-hole recombination rate was solved, achieving efficient photocatalytic hydrogen production and improving the stability and activity of the material.
Patent Information
- Application Number
- CN202511153531.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-18
- Publication Date
- 2025-11-28
AI Technical Summary
Existing photocatalytic materials such as TiO2 and CdS suffer from high recombination rates of photogenerated electrons and holes and poor stability. Furthermore, the high amount of precious metal co-catalysts increases material costs and fails to effectively improve the efficiency of photocatalytic hydrogen production.
Defective UiO-67 supports were prepared by adjusting ligand deficiency, and Pt/CdS@UiO-67 photocatalysts were prepared by loading CdS nanoparticles on the CdS surface via in-situ deposition and loading trace amounts of Pt cocatalysts on the CdS surface via photoreduction.
Optimize carrier migration pathways, reduce electron-hole recombination, achieve efficient photocatalytic hydrogen production, and improve material stability and activity.
Smart Images
Figure CN121016853A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of catalysts, in particular to a photocatalyst based on in-situ reconstruction of CdS / UiO-67, a preparation method and application thereof. BACKGROUND
[0002] The photocatalytic hydrogen production technology is a green energy technology for using solar energy to decompose water to produce hydrogen, which has broad application prospects. At present, the commonly used photocatalytic materials such as TiO2 and CdS have problems such as high photoelectron-hole recombination rate and poor stability. Metal organic framework (MOFs) material has become a new type of photocatalytic carrier due to its high specific surface area and adjustable structure, and UiO-67 has attracted much attention due to its good chemical stability and structural designability. However, the carrier of perfect crystal structure of UiO-67 has limited carrier migration efficiency, which limits its photocatalytic performance.
[0003] In the prior art, some researches have tried to load CdS semiconductor on MOFs material to improve the photocatalytic activity, but the problems of carrier defect regulation and synergistic effect of cocatalyst have not been solved, resulting in high photoelectron-hole recombination rate and insufficient hydrogen production efficiency. Moreover, the amount of noble metal cocatalyst (such as Pt) is high, which increases the cost of the material. SUMMARY
[0004] In view of the above problems in the prior art, the present application aims to provide a photocatalyst based on in-situ reconstruction of CdS / UiO-67, a preparation method and application thereof, and realize efficient photocatalytic hydrogen production.
[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:
[0006] On the one hand, a preparation method of a photocatalyst based on in-situ reconstruction of CdS / UiO-67 is provided, which comprises the following steps:
[0007] Step 1, preparing a defect type UiO-67 by adjusting ligand loss;
[0008] Step 2, loading CdS nanoparticles on the defect type UiO-67 by in-situ deposition method;
[0009] Step 3, loading Pt as a cocatalyst on the surface of CdS by photoreduction method to prepare Pt / CdS@UiO-67.
[0010] Further, the method of step 1 specifically comprises the following sub-steps:
[0011] (1) dissolving ZrCl4, diphenic acid and benzoic acid in N,N-dimethylformamide to obtain a mixed solution;
[0012] (2) the solution obtained in (1) is transferred to a reaction kettle for heating reaction;
[0013] (3) after the reaction is completed, centrifugation, washing, and then drying to obtain white powder;
[0014] (4) the white powder obtained in (3) is added into hydrochloric acid in which N,N-dimethylformamide is dissolved, oil bath reaction is performed, after the reaction is completed, centrifugation, washing, and then drying to obtain white powder defective type UiO-67.
[0015] Further, in step (2), the heating reaction condition is: heating at 120 DEG C for 24 h.
[0016] Further, in step (4), the oil bath reaction condition is: oil bath reaction at 90 DEG C for 24 h.
[0017] Further, the method of step 2 specifically comprises the following sub-steps:
[0018] (5) the defective type UiO-67 powder obtained in (4) is activated;
[0019] (6) after the activation is completed, N,N-dimethylformamide is added, and 2.5 hydrated cadmium chloride is added and ultrasonic dispersion is performed;
[0020] (7) after the ultrasonic dispersion is completed, sodium sulfide nine water is added dropwise, and stirring is performed in the dark;
[0021] (8) after the stirring is completed, the obtained solution is centrifuged, washed, and dried to obtain the product CdS@UiO-67.
[0022] Further, in step (5), the activation condition is: activation at 120 DEG C for 12 h.
[0023] Further, the method of step 3 specifically comprises the following sub-steps:
[0024] (9) the CdS@UiO-67 powder obtained in (8) is added into a heat-resistant glass tube, deionized water, methanol, and H2PtCl6 solution are added, and stirring is performed under light;
[0025] (10) after the stirring is completed, the obtained solution is centrifuged, washed, and dried to obtain yellow powder Pt / CdS@UiO-67.
[0026] On the other hand, the application provides the use of the photocatalyst Pt / CdS@UiO-67 based on CdS / UiO-67 in-situ reconstitution prepared by the above method in the decomposition of water to produce hydrogen.
[0027] The application has the following beneficial effects:
[0028] The present application optimizes the carrier migration path and reduces electron-hole recombination by introducing a defective UiO-67 carrier. By loading CdS semiconductor and trace Pt cocatalyst, efficient photocatalytic hydrogen production is achieved. The material stability and activity are further improved by using the structure reorganization characteristics after light irradiation. BRIEF DESCRIPTION OF DRAWINGS
[0029] Figure 1 TEM images (a-c), STEM images (d-f) and corresponding EDS element distribution maps (g-l) of Pt / CdS 0.7 ;
[0030] Figure 2 TEM images (a-c), STEM images (d-f) and corresponding EDS element distribution maps (g-l) of Pt / CdS 60 @UiO-67 0.7 ;
[0031] Figure 3 Photocatalytic hydrogen production yield (a) and rate (b) of UiO-67 with different defect ratios and hydrogen production activity (c) and rate (d) of the composite Pt / CdS@UiO-67 with different loadings of CdS;
[0032] Figure 4 TEM images (a-c), STEM images (d-f) and corresponding EDS element distribution maps (g-l) of Pt / CdS 60 @UiO-67 0.7 after light irradiation;
[0033] Figure 5 UV-Vis diffuse reflectance spectra (UV-Vis DRS) of UiO-67, CdS and Pt / CdS@UiO-67 0.7 0.7 . DETAILED DESCRIPTION
[0034] The specific embodiments of the present application are described below to facilitate the understanding of the present application for those skilled in the art, but it should be clear that the present application is not limited to the scope of the specific embodiments, and for those skilled in the art, all the changes that are obvious within the spirit and scope of the present application defined and determined by the appended claims are obvious, and all the inventions utilizing the concept of the present application are within the scope of protection.
[0035] Example 1
[0036] 1. Preparation of defective UiO-67 (by adjusting ligand loss).
[0037] (1) 0.120 g of zirconium tetrachloride (ZrCl4) and 0.087 g of biphenyl dicarboxylic acid (BPDC) and 0.628 g of benzoic acid were weighed and dissolved in 20 mL of N,N-dimethylformamide (DMF) to obtain a mixed solution;
[0038] (2) The solution obtained in (1) was transferred to a 50 mL reactor and heated at 120°C for 24 h.
[0039] (3) After the reaction was completed, centrifugation, washing, and then drying were performed to obtain a white powder.
[0040] (4) Subsequently, 600 mg of the white powder obtained in (3) was weighed and reacted in an 80 mL N,N-dimethylformamide and 0.4 mL hydrochloric acid at 90°C for 24 h in an oil bath, and after the reaction was completed, centrifugation, washing, and then drying were performed to obtain a white powder of defective UiO-67.
[0041] 2. CdS nanoparticles were loaded on the defective UiO-67 by an in-situ deposition method.
[0042] (5) 100 mg of the UiO-67 powder obtained in (4) was weighed and activated at 120°C for 12 h.
[0043] (6) After the activation was completed, 40 mL of N,N-dimethylformamide was added, and 1.30 mL of 0.8 mol / L cadmium chloride 2.5 hydrate was added and ultrasonicated for 2 h.
[0044] (7) After the ultrasonic dispersion was completed, 1.30 mL of 0.8 mol / L sodium sulfide 9 hydrate was added dropwise, and stirring was performed in the dark for 2 h.
[0045] (8) After the stirring was completed, the obtained solution was centrifuged, washed, and dried to obtain a product CdS 60 @UiO-67.
[0046] 3. A trace amount of Pt was loaded on the surface of CdS as a cocatalyst.
[0047] (9) 100 mg of the CdS@UiO-67 powder obtained in (8) was weighed in a heat-resistant glass tube, 20 mL of deionized water and 10 mL of methanol were added, and 27 uL of H2PtCl6 solution was added, and stirring was performed under xenon lamp light for 6 h.
[0048] (10) After the stirring was completed, the obtained solution was centrifuged, washed, and dried to obtain a yellow powder Pt / CdS 60 @UiO-67 0.7 .
[0049] Example 2
[0050] In the method steps of Example 2, the same as Example 1 are not described again here, only the different from Example 1 is described. Example 2 is different from Example 1 in that the CdS loading is different, and the rest is the same as described in Example 1, to prepare Pt / CdS 30 @UiO-67 0.7 .
[0051] Example 3
[0052] In the method steps of Example 3, the same as Example 1 are not described again here, only the different from Example 1 is described. Example 3 is different from Example 1 in that the CdS loading is different, and the rest is the same as described in Example 1, to prepare Pt / CdS 50 @UiO-67 0.7 .
[0053] Example 4
[0054] In the method steps of Example 4, the same as Example 1 are not described again here, only the different from Example 1 is described. Example 4 is different from Example 1 in that the CdS loading is different, and the rest is the same as described in Example 1, to prepare Pt / CdS 70 @UiO-67 0.7 .
[0055] Example 5
[0056] In the method steps of Example 5, the same as Example 1 are not described again here, only the different from Example 1 is described. Example 5 is different from Example 1 in that the CdS loading is different, and the rest is the same as described in Example 1, to prepare Pt / CdS 90 @UiO-67 0.7 .
[0057] Comparative Example 1
[0058] In the method steps of Comparative Example 1, the same as Example 1 are not described again here, only the different from Example 1 is described. Comparative Example 1 is different from Example 1 in that only defective UiO-67 is prepared.
[0059] Comparative Example 2
[0060] In the method steps of Comparative Example 2, the same as Example 1 are not described again here, only the different from Example 1 is described. Comparative Example 2 is different from Example 1 in that the amount of BPDC introduced is different, and the rest is the same as described in Example 1, to prepare UiO-67 0.9 , UiO-67 0.8 , UiO-67 0.6 .
[0061] Referring to Figure 1 , the X-ray diffraction pattern of UiO-67 is similar to that of defective UiO-67 and Pt / CdS@UiO-67, indicating that the introduction of defects, Pt and CdS does not significantly change the crystal structure of UiO-67.
[0062] Referring to Figure 2 , the surface morphology of Pt / CdS@UiO-67 was characterized by transmission electron microscopy and high-angle annular dark field scanning transmission electron microscopy. Pt / CdS@UiO-67 still has an octahedral shape, indicating that the morphology remains intact after modification with Pt and CdS. In addition, there is a thin film on the surface of the MOF, and from the EDS map, it can be analyzed that the Cd and S elements are uniformly distributed, indicating that the surface is a CdS film. In addition, it can be found from the EDS map that the Pt element exists on the MOF rather than on the CdS film.
[0063] Referring to Figure 3 , the effect of defects on photocatalytic hydrogen production was verified by changing the amount of defects in UiO-67. Figure 3 From (a-b), it can be seen that the presence of appropriate defects in UiO-67 can improve the hydrogen production performance, and the production of active sites can be controlled by creating an appropriate amount of defects. When the amount of defects is too low (UiO-67 0.8 ), it is not enough to create many active sites; and when the amount of defects is too high (UiO-67 0.6 ), the crystal structure of UiO-67 will collapse and the stability will be destroyed. Then by changing the loading amount of CdS, further preparation of photocatalysts was carried out for performance comparison test. From Figure 3 (c-d), it can be seen that the Pt / CdS 10 @UiO-67 0.7 compared with pure CdS hydrogen production rate, indicating that UiO-67 as a carrier can improve the hydrogen production performance. At the same time, with the increase of the loading amount of CdS, the hydrogen production rate also increases. When the loading amount of CdS reaches 60%, the hydrogen production rate reaches a maximum of 5.181 mmol / g / h. Continuing to increase the loading amount of CdS, the hydrogen production rate decreases, which indicates that the loading amount of CdS is an important factor affecting the photohydrolysis hydrogen production.
[0064] Referring to Figure 4 , the morphology of Pt / CdS 60 @UiO-67 0.7 after light reaction was characterized by transmission electron microscopy and high-angle annular dark field scanning transmission electron microscopy. The figure shows that the catalyst after light still maintains an octahedral shape, indicating that the structure of UiO-67 is stable. From the EDS map, it can be seen that the elements Cd, S and Pt are still uniformly distributed after light.
[0065] Referring to Figure 5 , the incorporation of CdS and Pt significantly improves the light absorption range of UiO-67, and single UiO-67 0.7 shows light absorption performance in the wavelength range of 250-350 nm, indicating that pure UiO-67 does not absorb visible light and has no hydrogen production performance under visible light. Single CdS has absorption intensity in the visible light range, but the absorption intensity is limited, and the absorption edge is about 475 nm. For the composite Pt / CdS@UiO-67 0.7 , with the increase of the loading amount of CdS, the composite Pt / CdS@UiO-67 0.7 enhances the ability to absorb visible light in the wavelength range of 400-600 nm. The introduction of Pt and CdS improves the light absorption performance, and the defects of UiO-67 are also beneficial to the more efficient separation and migration of photo-generated carriers. All the composites Pt / CdS@UiO-67 0.7 show enhanced light absorption performance in the visible light region, which adds more active sites for photocatalytic reaction and is beneficial to the photocatalytic hydrogen production reaction.
[0066] In summary, by introducing the defect UiO-67 carrier, the carrier migration path is optimized, and the electron-hole recombination is reduced. By loading CdS semiconductor and trace Pt cocatalyst, efficient photocatalytic hydrogen production is realized. The structure recombination characteristics after light irradiation further improve the stability and activity of the material.
[0067] It is apparent to those skilled in the art that the application is not limited to the details of the foregoing exemplary embodiments, and that the application can be implemented in other specific forms without departing from the spirit or essential characteristics of the application. Therefore, the embodiments should be considered in all respects as illustrative and not restrictive, and the scope of the application is defined by the appended claims rather than the above description, and it is intended to encompass all changes falling within the meaning and range of equivalents of the elements of the claims.
[0068] In addition, it should be understood that although the present specification is described in terms of embodiments, each embodiment does not contain only one independent technical solution, and the description manner of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be properly combined to form other embodiments that those skilled in the art can understand.
Claims
1. A method for preparing a photocatalyst based on in-situ reconstruction of CdS / UiO-67, characterized in that, Includes the following steps: Step 1: Prepare defective UiO-67 by adjusting ligand deletion; Step 2: Load CdS nanoparticles onto defect-type UiO-67 by in-situ deposition, wherein the mass ratio of CdS to UiO-67 is 30-90 wt%. Step 3: Load 1 wt% Pt onto the CdS surface as a co-catalyst and prepare Pt / CdS@UiO-67 by photoreduction.
2. The method for preparing a photocatalyst based on in-situ reconstruction of CdS / UiO-67 according to claim 1, characterized in that, Step 1 specifically includes the following sub-steps: (1) Dissolve ZrCl4, biphenyl dicarboxylic acid, and benzoic acid in N,N-dimethylformamide to obtain a mixed solution; (2) Transfer the solution obtained in (1) to a reaction vessel and heat it to react; (3) After the reaction is complete, centrifuge, wash, and then dry to obtain a white powder; (4) Add the white powder obtained in (3) to hydrochloric acid containing N,N-dimethylformamide, react in an oil bath, centrifuge, wash, and then dry to obtain defective UiO-67.
3. The method for preparing a photocatalyst based on in-situ reconstruction of CdS / UiO-67 according to claim 2, characterized in that, In step (2), the heating reaction conditions are: heating at 120℃ for 24 hours.
4. The method for preparing a photocatalyst based on in-situ reconstruction of CdS / UiO-67 according to claim 2, characterized in that, In step (4), the oil bath reaction conditions are: 90℃ oil bath reaction for 24h.
5. The method for preparing a photocatalyst based on in-situ reconstruction of CdS / UiO-67 according to claim 2, characterized in that, Step 2 specifically includes the following sub-steps: (5) Activate the defective UiO-67 powder obtained in (4); (6) After activation, add N,N-dimethylformamide and 2,5-hydrated cadmium chloride and disperse by ultrasonication; (7) After ultrasonic dispersion is completed, add sodium sulfide nonahydrate dropwise and stir in the dark; (8) After stirring, the resulting solution is centrifuged, washed, and dried to obtain the product CdS@UiO-67.
6. The method for preparing a photocatalyst based on in-situ reconstruction of CdS / UiO-67 according to claim 5, characterized in that, In step (5), the activation conditions are: activation at 120℃ for 12h.
7. The method for preparing a photocatalyst based on in-situ reconstruction of CdS / UiO-67 according to claim 5, characterized in that, Step 3 specifically includes the following sub-steps: (9) Place the CdS@UiO-67 powder obtained in (8) in a heat-resistant glass tube, add deionized water, methanol and H2PtCl6 solution, and stir under light; (10) After stirring, the resulting solution is centrifuged, washed, and dried to obtain the yellow powder Pt / CdS@UiO-67.
8. The photocatalyst Pt / CdS@UiO-67 based on in-situ reconstruction of CdS / UiO-67 prepared by the method according to any one of claims 1-7.
9. The application of the photocatalyst Pt / CdS@UiO-67 according to claim 8 in water splitting for hydrogen production.