Preparation Method and Application of a Highly Dispersed Noble Metal Photothermal Catalyst

Abstract

The present invention belongs to the technical field of catalyst preparation, and relates to a preparation method and application of a highly dispersed noble metal photothermal catalyst. In the present invention, a metal oxide with a special morphology such as sheet-like, rod-like or tubular and strong photothermal conversion performance is used as a carrier, and a noble metal salt is used as a precursor of the loading substance, and a highly dispersed noble metal photothermal catalyst is prepared through reduction treatment. The present invention uses a metal oxide with a special regular morphology as a carrier to load noble metal particles, utilizes the microscopic structural characteristics of the carrier to improve the dispersion degree of the noble metal, and utilizes the interaction between noble metal nanoparticles and the metal oxide to inhibit the agglomeration of noble metal particles and improve the stability of the catalyst.

Description

Technical Field

[0001] The present invention relates to the technical field of catalyst preparation, and particularly relates to a preparation method and application of a highly dispersed noble metal photothermal catalyst. Background Art

[0002] The emission of a large amount of volatile organic compounds causes serious harm to the environment and human body, and catalytic oxidation is the most effective way to degrade volatile organic compounds. Conventional thermal catalytic degradation technology relies on fossil fuels to provide energy, which has an impact on resources and the environment, and the required equipment is complex and the operation has certain risks. Photothermal catalytic technology can convert visible light into heat energy to drive chemical reactions without the need to provide additional heat sources. At the same time, compared with traditional photocatalysis, photothermal catalyst technology has higher light energy utilization efficiency and faster reaction rate. The research and development of efficient photothermal catalysts is the key to promoting the development of photothermal technology.

[0003] In the volatile organic compound removal technology, the adsorption technology requires frequent replacement of the adsorption material, and the used material is a hazardous waste that requires secondary treatment; the photocatalytic technology saves energy, but has low removal efficiency and poor stability; the thermal catalytic technology consumes fossil energy and will produce secondary pollution. Photothermal catalytic technology converts light energy into heat energy to drive chemical reactions, which has the advantages of both energy saving and high efficiency. However, efficient photothermal catalysts are currently lacking, and the reported photothermal catalysts generally have low light energy utilization efficiency, require strong light intensity during the reaction process, and have relatively harsh use conditions, resulting in difficulties in practical applications. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method and application of a highly dispersed noble metal photothermal catalyst to solve the problems existing in the above-mentioned prior art.

[0005] To achieve the above purpose, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention: Provide a preparation method of a highly dispersed noble metal photothermal catalyst, and the steps include:

[0007] Using metal oxide as a carrier and noble metal salt as a precursor of the loading substance, and obtaining the highly dispersed noble metal photothermal catalyst through reduction treatment;

[0008] The metal oxide includes MnO x , CoO x and CuO x at least one of them;

[0009] The noble metal salt includes at least one of soluble salts of Pt, Au, Ag or Pd.

[0010] Preferably, the metal oxide has a special morphology of flake, rod or tube shape and has strong photothermal conversion performance.

[0011] Further, the reduction treatment includes gas-phase reduction treatment or liquid-phase reduction treatment.

[0012] Preferably, the gas-phase reduction treatment includes H 2 reduction or CO reduction.

[0013] Preferably, the liquid-phase reduction treatment includes NaBH 4 reduction, NaH 2 PO 2 reduction or N 2 H 4 ·H 2 O reduction.

[0014] Further, the noble metal loading in the highly dispersed noble metal photothermal catalyst is 0.25-10 wt%.

[0015] Further, the preparation steps of the MnO x include:

[0016] Dissolve KMnO 4 and MnSO 4 ·H 2 O in water, stir for 0.5 h, then perform heat treatment at 160 °C for 24 h. After cooling, wash, dry and calcine to obtain rod-shaped MnO x .

[0017] Preferably, the dosage ratio of KMnO 4 , MnSO 4 ·H 2 O and water is 1.5 g: 0.275 g: 80 mL.

[0018] Preferably, the washing is performed by alternately washing with water and ethanol at least once.

[0019] Preferably, the drying temperature is 60 °C and the time is 24 h.

[0020] Preferably, the calcination is performed in an air atmosphere, the temperature is 500 °C, the heating rate is 1 °C / min, and the time is 3 h.

[0021] Further, the preparation steps of the CoO x include:

[0022] Dissolve Co(NO 3 ) 2 ·6H 2O is dissolved in isopropyl alcohol, and then a sodium carbonate solution with a concentration of 1.0 mol / L is added. After stirring for 0.5 h, it is heat-treated at 160 °C for 4 h. After cooling, it is washed, dried, and calcined to obtain nano-sheet CoO x .

[0023] Preferably, the dosage ratio of Co(NO 3 ) 2 ·6H 2 O to isopropyl alcohol is 0.01 mol: 50 mL.

[0024] Preferably, the volume ratio of isopropyl alcohol to sodium carbonate solution is 5:2.

[0025] Preferably, the washing is to wash at least once with water and ethanol respectively.

[0026] Preferably, the drying temperature is 60 °C and the time is 12 h.

[0027] Preferably, the calcination is carried out in an air atmosphere, the temperature is 300 °C, the heating rate is 5 °C / min, and the time is 2 h.

[0028] Furthermore, the preparation steps of the CuO x include:

[0029] Dissolve Cu(NO 3 ) 2 ·3H 2 O in water, then add a sodium hydroxide solution with a concentration of 1.5 mol / L, stir at 80 °C for 0.5 h, add ethylenediamine and ammonia water in sequence, continue stirring for 0.5 h, and obtain nano-tubular CuO after washing, drying, and calcination x .

[0030] Preferably, the dosage ratio of Cu(NO 3 ) 2 ·3H 2 O to water is 0.01 mol: 30 mL.

[0031] Preferably, the volume ratio of water to sodium hydroxide solution is 6:1.

[0032] Preferably, the volume ratio of water, ethylenediamine, and ammonia water is 6:2:3.

[0033] Preferably, the washing is to wash at least once with water and ethanol respectively.

[0034] Preferably, the drying temperature is 80 °C and the time is 12 h.

[0035] Preferably, the calcination is carried out in an air atmosphere, the temperature is 500 °C, the heating rate is 2 °C / min, and the time is 4 h.

[0036] The second technical solution of the present invention: Provide a highly dispersed noble metal photothermal catalyst prepared by the above preparation method.

[0037] The third technical solution of the present invention: Provide an application of the above highly dispersed noble metal photothermal catalyst in the photothermal catalytic oxidation and degradation of volatile organic compounds.

[0038] Improving the photothermal conversion efficiency of the photothermal catalyst and reducing the light intensity required for the reaction are effective ways to improve its performance. Using metal oxides with high photothermal conversion performance as the carrier can enhance the overall photothermal conversion efficiency of the catalyst, thereby increasing the surface temperature during illumination. Loading noble metal nanoparticles and utilizing their light absorption characteristics and good low-temperature catalytic performance, combined with the coordinated catalytic effects of metal oxides and noble metal nanoparticles, can significantly reduce the light intensity required for the catalyst during the photothermal catalytic degradation of volatile organic compounds. Such catalysts have a simple synthesis method and good stability, and have strong practical application value.

[0039] The present invention discloses the following technical effects:

[0040] The present invention uses metal oxides with special regular morphologies as carriers to load noble metal particles, utilizes the microstructural characteristics of the carriers to improve the dispersion of noble metals, and uses the interaction between noble metal nanoparticles and metal oxides to inhibit the aggregation of noble metal particles and improve the stability of the catalyst.

[0041] The present invention uses metal oxides with strong photothermal conversion performance as the substrate to improve the overall photothermal conversion efficiency, and uses noble metal nanoparticles with good low-temperature catalytic performance as the active sites to reduce the temperature required for the catalytic reaction, thereby reducing the overall light intensity required for the catalyst. Description of the Drawings

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0043] Figure 1 The nano-sheet-like CoO prepared for Example 1 x Scanning electron microscopy image of the carrier and 0.5 wt% Pt / CoO x Scanning electron microscopy image, transmission electron microscopy image, and energy-dispersive spectroscopy of the photothermal catalyst. Among them, (a) is the nano-sheet-like CoO x Scanning electron microscopy image of the carrier, (b) is 0.5 wt% Pt / CoO xScanning electron microscopy images of the photothermal catalyst, (c)–(e) are 0.5 wt% Pt / CoO x Transmission electron microscopy images of the photothermal catalyst, (f)–(h) are 0.5 wt% Pt / CoO x Energy-dispersive spectroscopy of the photothermal catalyst;

[0044] Figure 2 is 0.5 wt% Pt / CoO x is the toluene degradation efficiency and CO 2 mineralization efficiency of the catalyst under experimental condition 1;

[0045] Figure 3 is 0.5 wt% Pt / CoO x is the toluene degradation efficiency and CO 2 mineralization efficiency of the catalyst under experimental condition 2;

[0046] Figure 4 is 0.5 wt% Pt / CoO x is the toluene degradation efficiency and CO 2 mineralization efficiency of the catalyst in the 8-cycle reaction under experimental condition 2;

[0047] Figure 5 is 0.5 wt% Pt / CoO x and CoO x The carrier is the toluene degradation efficiency and CO 2 mineralization efficiency of the catalyst under experimental condition 3, where (a) is the toluene degradation efficiency and (b) is the CO 2 mineralization efficiency;

[0048] Figure 6 is 0.5 wt% Pt / CoO x is the acetone degradation efficiency and CO 2 mineralization efficiency of the catalyst under experimental condition 4;

[0049] Figure 7 is 0.5 wt% Pt / CoO x is the formaldehyde degradation efficiency and CO 2 mineralization efficiency of the catalyst under experimental condition 5;

[0050] Figure 8 is 2 wt% Pt / CoO x is the toluene degradation efficiency and CO 2 mineralization efficiency of the catalyst under experimental condition 6;

[0051] Figure 9 is 5 wt% Pt / CoO x is the toluene degradation efficiency and CO 2 mineralization efficiency of the catalyst under experimental condition 7;

[0052] Figure 10 is the toluene degradation efficiency and CO x mineralization efficiency of the catalyst with 0.25 wt% Pt / CoO under experimental condition 8; 2

[0053] Figure 11 is the toluene degradation efficiency and CO x (H 2 reduction method) mineralization efficiency of the catalyst with 0.5 wt% Pt / CoO under experimental condition 9; 2

[0054] Figure 12 is the toluene degradation efficiency and CO x mineralization efficiency of the catalyst with 0.25 wt% Pt + 0.25 wt% Pd / CoO under experimental condition 10; 2

[0055] Figure 13 is the scanning electron micrograph of the rod-shaped MnO x support prepared in Example 7;

[0056] Figure 14 is the toluene degradation efficiency and CO x mineralization efficiency of the catalyst with 0.5 wt% Pt / MnO under experimental condition 11; 2

[0057] Figure 15 is the toluene degradation efficiency and CO x -MnO x mineralization efficiency of the catalyst with 0.5 wt% Pt / CoO -MnO under experimental condition 12; 2

[0058] Figure 16 is the scanning electron micrograph of the tubular CuO x support prepared in Example 9;

[0059] Figure 17 is the toluene degradation efficiency and CO x mineralization efficiency of the catalyst with 0.5 wt% Pt / CuO under experimental condition 13; 2

[0060] Figure 18 is the scanning electron micrograph of the shapeless CoO x support prepared in Comparative Example 1;

[0061] Figure 19 is the toluene degradation efficiency and CO x ​​​​​​(Amorphous) is the toluene degradation efficiency and CO 2 mineralization efficiency of the catalyst under experimental condition 14;

[0062] Figure 20 is 0.5 wt% Pt / CoO x (Amorphous) is the toluene degradation efficiency and CO 2 mineralization efficiency of the catalyst under experimental condition 15;

[0063] Figure 21 is 0.5 wt% Pt / C 3 N 4 is the toluene degradation efficiency and CO 2 mineralization efficiency of the catalyst under experimental condition 16;

[0064] Figure 22 is 0.5 wt% Pt / Al 2 O 3 is the toluene degradation efficiency and CO 2 mineralization efficiency of the catalyst under experimental condition 17. Detailed implementation manners

[0065] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be considered as a limitation to the present invention, but should be understood as a more detailed description of certain aspects, characteristics and implementation schemes of the present invention.

[0066] It should be understood that the terms described in the present invention are only for describing specific implementation manners and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0067] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0068] Without departing from the scope or spirit of the present invention, various modifications and variations can be made to the specific embodiments of the present invention specification, which are obvious to those skilled in the art. Other embodiments obtained from the present invention specification are obvious to those skilled in the art. The present invention specification and examples are merely exemplary.

[0069] Regarding "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, meaning including but not limited to.

[0070] Unless otherwise specified, room temperature and normal temperature referred to in the specific embodiments of the present invention both refer to 20 - 30 °C.

[0071] Example 1

[0072] The preparation steps of the highly dispersed noble metal photothermal catalyst are as follows:

[0073] S1. Dissolve 2.9191 g of Co(NO 3 ) 2 ·6H 2 O in 50 mL of isopropanol, then dropwise add 20 mL of sodium carbonate solution (1.0 mol / L), stir for 0.5 h, then transfer it to a stainless steel autoclave, and perform heat treatment at 160 °C for 4 h. After the reaction ends, cool the autoclave to room temperature, wash the precipitate with deionized water and absolute ethanol 4 times respectively, then dry it at 60 °C for 12 h, and finally calcine it in air at 300 °C for 2 h, with a heating rate of 5 °C·min -1 to obtain a nano-sheet-like CoO x support;

[0074] S2. Disperse 0.6 g of the nano-sheet-like CoO x support in 30 mL of deionized water, then add 7.4 mL of 1 g / L K 2 PtCl 6 solution, stir for 1 h, then add the reducing agent NaBH 4 solution (NaBH 4 / Pt = 5 / 1, molar ratio) and continue to stir for 1 h. After that, wash it alternately with deionized water and absolute ethanol 6 times, and dry it at 80 °C for 12 h to obtain the highly dispersed noble metal photothermal catalyst, denoted as 0.5 wt% Pt / CoO x photothermal catalyst.

[0075] Figure 1 Shown are the scanning electron microscope images of the nano-sheet-like CoO x support prepared in Example 1 and the scanning electron microscope images, transmission electron microscope images, and energy dispersive spectroscopy of the 0.5 wt% Pt / CoO x photothermal catalyst, where (a) is the nano-sheet-like CoOx Scanning electron microscopy image of the support, (b) is 0.5 wt% Pt / CoO x Scanning electron microscopy image of the photothermal catalyst, (c)-(e) are 0.5 wt% Pt / CoO x Transmission electron microscopy image of the photothermal catalyst, (f)-(h) are 0.5 wt% Pt / CoO x Energy dispersive spectrum of the photothermal catalyst. It can be seen from Figure 1 that loading the noble metal Pt on the nanosheet CoO x support does not change the morphology of the support, and Pt NPs are evenly dispersed on the CoO x support.

[0076] The obtained 0.5 wt% Pt / CoO x photothermal catalyst was applied to the photothermal degradation experiment:

[0077] Experimental condition 1: Static reaction (The static reaction was carried out in a closed cylindrical quartz gas-phase reactor with a height of 450 mL and a diameter of 110 mL. 100 mg of the catalyst was evenly coated on a glass fiber filter membrane with a diameter of 50 nm and a pore size of 0.1 μm, and it was placed at the bottom of the glass reactor. During the experiment, liquid toluene was injected into the quartz reactor through a silicone rubber sealed injection port and completely volatilized by an external heating device. After the system was stable, the xenon lamp placed above the quartz window was turned on to start the reaction), toluene concentration 400 ppm, O 2 concentration 310 mg / L, light intensity 270 mW / cm 2 , and the results are as Figure 2 shown.

[0078] Figure 2 Taking 0.5 wt% Pt / CoO x as the catalyst, the toluene degradation efficiency and CO 2 mineralization efficiency in experimental condition 1 are shown. It can be seen from Figure 2 that at a light intensity of 270 mW / cm 2 , for the 0.5 wt% Pt / CoO x catalyst, when the reaction proceeds for 20 min, the toluene degradation efficiency and CO 2 mineralization efficiency can reach 100%, proving that the 0.5 wt% Pt / CoO x catalyst has excellent photothermal catalytic performance.

[0079] Experimental condition 2: Static reaction, toluene concentration 400 ppm, O 2 concentration 310 mg / L, light intensity 200 mW / cm 2 , and the results are as Figure 3 shown.

[0080] Figure 3 Using 0.5 wt% Pt / CoO x as the catalyst, the toluene degradation efficiency and CO 2 mineralization efficiency in experimental condition 2 are shown. From Figure 3 it can be seen that under the light intensity of 200 mW / cm 2 , when the reaction proceeds for 40 min with the 0.5 wt% Pt / CoO x catalyst, the toluene degradation efficiency is 96%, and the CO 2 mineralization efficiency is 82%, proving that the 0.5 wt% Pt / CoO x catalyst also has excellent photothermal catalytic performance under low light intensity.

[0081] Figure 4 Using 0.5 wt% Pt / CoO x as the catalyst, the toluene degradation efficiency and CO 2 mineralization efficiency during 8 cycles of the reaction in experimental condition 2 are shown. From Figure 4 it can be seen that under the light intensity of 200 mW / cm 2 , after 8 cycles of the reaction, the 0.5 wt% Pt / CoO x catalyst can still maintain excellent photothermal catalytic performance, proving that the 0.5 wt% Pt / CoO x catalyst has excellent durability and stability.

[0082] Experimental condition 3: Thermal catalytic reaction (the thermal catalytic reaction is carried out in a fixed-bed quartz tube reactor with an inner diameter of 6 mm and a total length of 500 mm. 50 mg of the catalyst is filled in the quartz tube reactor. At different temperatures, the outlet products are measured by gas chromatography, and the catalytic activity of the catalyst is evaluated by the temperature (T90%) required for the toluene conversion rate of the catalyst to reach 90%), a mixed reaction gas of 100 mL / min (200 ppm toluene, 20 vol% O 2 +N 2 ), mass hourly space velocity (WHSV) of 30000 mL·g -1 ·h -1 , and the results are as Figure 5 shown.

[0083] Figure 5 Using 0.5 wt% Pt / CoO x and CoO x supported on the carrier as the catalyst, the toluene degradation efficiency and CO 2 mineralization efficiency in experimental condition 3 are shown, where (a) is the toluene degradation efficiency and (b) is the CO 2 mineralization efficiency. From Figure 5 it can be seen that the 0.5 wt% Pt / CoO prepared by the present inventionx Compared with CoO x it can significantly reduce the temperature required for the catalytic reaction.

[0084] Experimental condition 4: Static reaction, acetone concentration 405 ppm, O 2 concentration 310 mg / L, light intensity 200 mW / cm 2 , and the results are as Figure 6 shown.

[0085] Figure 6 Figure x shows the acetone degradation efficiency and CO 2 mineralization efficiency of 0.5 wt% Pt / CoO Figure 6 as the catalyst under experimental condition 4. It can be seen from 2 that under the light intensity of 200 mW / cm x , when the reaction proceeds for 25 min, the acetone degradation efficiency and CO 2 mineralization efficiency of the 0.5 wt% Pt / CoO x catalyst can reach 100%, proving that the 0.5 wt% Pt / CoO

[0086] catalyst also has excellent photothermal catalytic performance for high-concentration acetone. 2 Experimental condition 5: Static reaction, formaldehyde concentration 530 ppm, O 2 concentration 310 mg / L, light intensity 200 mW / cm Figure 7 , and the results are as

[0087] Figure 7 Figure x shows the formaldehyde degradation efficiency and CO 2 mineralization efficiency of 0.5 wt% Pt / CoO Figure 7 as the catalyst under experimental condition 5. It can be seen from 2 that under the light intensity of 200 mW / cm x , when the reaction proceeds for 40 min, the formaldehyde degradation efficiency of the 0.5 wt% Pt / CoO 2 catalyst is 100%, and the CO x mineralization efficiency is 86%, proving that the 0.5 wt% Pt / CoO

[0088] Example 2

[0089] Compared with Example 1, the difference is only that in step S2, the content of the added K 2 PtCl 6 solution is changed to 29.6 mL of 1 g / L K 2 PtCl 6, the prepared highly dispersed noble metal photocatalytic thermal catalyst is denoted as 2wt% Pt / CoO x Photocatalytic thermal catalyst.

[0090] The obtained 2wt% Pt / CoO x Photocatalytic thermal catalyst is applied to the photocatalytic thermal degradation experiment:

[0091] Experimental condition 6: Static reaction, toluene concentration 400 ppm, O 2 Concentration 310 mg / L, light intensity 270 mW / cm 2 , and the results are as Figure 8 shown.

[0092] Figure 8 Taking 2wt% Pt / CoO x as the catalyst, the toluene degradation efficiency and CO 2 mineralization efficiency in experimental condition 6 are shown. It can be seen from Figure 8 that under the light intensity of 270 mW / cm 2 , when the reaction proceeds for 40 min with the 2wt% Pt / CoO x catalyst, the toluene degradation efficiency is 87%, and the CO 2 mineralization efficiency is 43%.

[0093] Example 3

[0094] Compared with Example 1, the difference is only that in step S2, the content of the added K 2 PtCl 6 solution is changed to 74 mL of 1 g / L K 2 PtCl 6 , and the prepared highly dispersed noble metal photocatalytic thermal catalyst is denoted as 5wt% Pt / CoO x Photocatalytic thermal catalyst.

[0095] The obtained 5wt% Pt / CoO x Photocatalytic thermal catalyst is applied to the photocatalytic thermal degradation experiment:

[0096] Experimental condition 7: Static reaction, toluene concentration 400 ppm, O 2 Concentration 310 mg / L, light intensity 270 mW / cm 2 , and the results are as Figure 9 shown.

[0097] Figure 9 Taking 5wt% Pt / CoO x as the catalyst, the toluene degradation efficiency and CO 2 mineralization efficiency in experimental condition 7 are shown. It can be seen from Figure 9 that under the light intensity of 270 mW / cm 2Under the light intensity of, 5wt% Pt / CoO x When the reaction proceeded for 40 min, the toluene degradation efficiency of the catalyst was 28%, and the CO 2 mineralization efficiency was 10%.

[0098] Example 4

[0099] Compared with Example 1, the difference is only that in step S2, the content of the added K 2 PtCl 6 solution was changed to 3.7 mL of 1 g / L K 2 PtCl 6 The highly dispersed noble metal photocatalytic thermal catalyst thus prepared was denoted as 0.25wt% Pt / CoO x photocatalytic thermal catalyst.

[0100] The obtained 0.25wt% Pt / CoO x photocatalytic thermal catalyst was applied to the photocatalytic thermal degradation experiment:

[0101] Experimental condition 8: Static reaction, toluene concentration 400 ppm, O 2 concentration 310 mg / L, light intensity 270 mW / cm 2 , and the results are as Figure 10 shown.

[0102] Figure 10 The toluene degradation efficiency and CO x mineralization efficiency of 0.25wt% Pt / CoO 2 as the catalyst under experimental condition 8. It can be seen from Figure 10 that under the light intensity of 270 mW / cm 2 , when the reaction proceeded for 40 min, the toluene degradation efficiency of the 0.25wt% Pt / CoO x catalyst was 39%, and the CO 2 mineralization efficiency was 22%.

[0103] Example 5

[0104] Compared with Example 1, the difference is only that in step S2, the sample after adding 7.4 mL of 1 g / L K 2 PtCl 6 solution was stirred for 1 h. After washing and drying, it was calcined at 300 °C for 1 h in a 5% H 2 / Ar atmosphere, and the heating rate was 2 °C·min -1 . The highly dispersed noble metal photocatalytic thermal catalyst thus prepared was denoted as 0.5wt% Pt / CoO x (H 2 reduction method) photocatalytic thermal catalyst.

[0105] The obtained 0.5 wt% Pt / CoO x (H 2 reduction method) photocatalytic thermal catalyst was applied to the photocatalytic thermal degradation experiment:

[0106] Experimental condition 9: static reaction, toluene concentration 400 ppm, O 2 concentration 310 mg / L, light intensity 270 mW / cm 2 , and the results are as Figure 11 shown.

[0107] Figure 11 The toluene degradation efficiency and CO x (H 2 mineralization efficiency of the reduction method) catalyst under experimental condition 9. It can be seen from 2 that under the light intensity of 270 mW / cm Figure 11 , when the reaction proceeded for 40 min, the toluene degradation efficiency of the 0.5 wt% Pt / CoO 2 (H x reduction method) catalyst was 77%, and the CO 2 mineralization efficiency was 34%. 2

[0108] Example 6

[0109] Compared with Example 1, the difference is only that in step S2, the content of the added K 2 PtCl 6 solution was changed to 3.7 mL of 1 g / L K 2 PtCl 6 solution and 1.8 mL of 1 g / L Pd(NO 3 ) 2 solution, and the prepared highly dispersed noble metal photocatalytic thermal catalyst was denoted as 0.25 wt% Pt + 0.25 wt% Pd / CoO x photocatalytic thermal catalyst.

[0110] The obtained 0.25 wt% Pt + 0.25 wt% Pd / CoO x photocatalytic thermal catalyst was applied to the photocatalytic thermal degradation experiment:

[0111] Experimental condition 10: static reaction, toluene concentration 400 ppm, O 2 concentration 310 mg / L, light intensity 270 mW / cm 2 , and the results are as Figure 12 shown.

[0112] Figure 12 The toluene degradation efficiency and CO x ​The toluene degradation efficiency and CO 2 mineralization efficiency of the catalyst under experimental condition 10. It can be seen from Figure 12 that under the light intensity of 270 mW / cm 2 , for the 0.25 wt% Pt + 0.25 wt% Pd / CoO x catalyst, when the reaction proceeds for 40 min, the toluene degradation efficiency is 98%, and the CO 2 mineralization efficiency is 92%.

[0113] Example 7

[0114] The preparation steps of the highly dispersed noble metal photothermal catalyst are as follows:

[0115] S1. Dissolve 1.5 g of KMnO 4 and 0.275 g of MnSO 4 ·H 2 O in 80 mL of deionized water. After stirring for 0.5 h, transfer the mixed solution to a stainless steel autoclave and heat-treat it at 160 °C for 24 h. After the reaction ends, cool the autoclave to room temperature. Wash the precipitate alternately with deionized water and absolute ethanol 6 times, then dry it at 60 °C for 24 h, and finally calcine it in air at 500 °C for 3 h with a heating rate of 1 °C·min -1 to obtain rod-shaped MnO x support;

[0116] S2. Disperse 0.6 g of the rod-shaped MnO x support in 30 mL of deionized water. Take 7.4 mL of 1 g / L K 2 PtCl 6 solution and add it to the above solution and stir for 1 h. Then add the reducing agent NaBH 4 solution (NaBH 4 / Pt = 5 / 1, molar ratio) and continue to stir for 1 h. After that, wash it alternately with deionized water and absolute ethanol 6 times and dry it at 80 °C for 12 h to obtain the highly dispersed noble metal photothermal catalyst, denoted as 0.5 wt% Pt / MnO x photothermal catalyst.

[0117] Figure 13 Figure is the scanning electron microscope image of the rod-shaped MnO x support prepared in Example 7. It can be seen from Figure 13 that the MnO x support presents a rod-shaped morphology.

[0118] Apply the obtained 0.5 wt% Pt / MnO x photothermal catalyst to the photothermal degradation experiment:

[0119] Experimental condition 11: Static reaction, toluene concentration 400 ppm, O 2 concentration 310 mg / L, light intensity 270 mW / cm 2 , and the results are as Figure 14 shown.

[0120] Figure 14 The toluene degradation efficiency and CO x mineralization efficiency of 0.5 wt% Pt / MnO 2 as the catalyst under experimental condition 11. It can be seen from Figure 14 that under the light intensity of 270 mW / cm 2 , when the reaction proceeds for 40 min, the toluene degradation efficiency of 0.5 wt% Pt / MnO x catalyst is 92%, and the CO 2 mineralization efficiency is 46%.

[0121] Example 8

[0122] The preparation steps of the highly dispersed noble metal photothermal catalyst are as follows:

[0123] Disperse 0.6 g of the carrier (the nanosheet CoO prepared in Example 1 x and the rod-shaped MnO prepared in Example 7 x mixed in a mass ratio of 1:1) in 30 mL of deionized water, then add 7.4 mL of 1 g / L K 2 PtCl 6 solution, stir for 1 h, then add the reducing agent NaBH 4 solution (NaBH 4 / Pt = 5 / 1, molar ratio) and continue to stir for 1 h. After that, wash alternately with deionized water and absolute ethanol 6 times and dry at 80 °C for 12 h to obtain the highly dispersed noble metal photothermal catalyst, denoted as 0.5 wt% Pt / CoO x -MnO x photothermal catalyst.

[0124] Apply the obtained 0.5 wt% Pt / CoO x -MnO x photothermal catalyst to the photothermal degradation experiment:

[0125] Experimental condition 12: Static reaction, toluene concentration 400 ppm, O 2 concentration 310 mg / L, light intensity 270 mW / cm 2 , and the results are as Figure 15 shown.

[0126] Figure 15 The toluene degradation efficiency and CO x -MnOx The toluene degradation efficiency and CO 2 mineralization efficiency of the catalyst under experimental condition 12. It can be seen from Figure 15 that under the light intensity of 270 mW / cm 2 , for the 0.5 wt% Pt / CoO x -MnO x catalyst, when the reaction proceeds for 40 min, the toluene degradation efficiency is 97%, and the CO 2 mineralization efficiency is 88%.

[0127] Example 9

[0128] The preparation steps of the highly dispersed noble metal photothermal catalyst are as follows:

[0129] S1. Dissolve 2.416 g of Cu(NO 3 ) 2 ·3H 2 O in 30 mL of deionized water, then dropwise add 5 mL of sodium hydroxide solution (1.5 mol / L), stir in an oil bath at 80 °C for 0.5 h, successively add 10 mL of ethylenediamine and 15 mL of ammonia water, continuously stir for 0.5 h, separate the precipitate from the solution by centrifugation, and wash it alternately with deionized water and absolute ethanol 6 times. The precipitate is dried at 80 °C for 12 h. Finally, calcine it in air at 500 °C for 4 h with a heating rate of 2 °C min -1 to obtain tubular CuO x support;

[0130] S2. Disperse 0.6 g of the tubular CuO x support in 30 mL of deionized water, take 7.4 mL of 1 g / L K 2 PtCl 6 solution and add it to the above solution and stir for 1 h, then add the reducing agent NaBH 4 solution (NaBH 4 / Pt = 5 / 1, molar ratio) and continue to stir for 1 h. After that, wash it alternately with deionized water and absolute ethanol 6 times and dry it at 80 °C for 12 h to obtain the highly dispersed noble metal photothermal catalyst, denoted as 0.5 wt% Pt / CuO x photothermal catalyst.

[0131] Figure 16 Figure 53 is the scanning electron microscope image of the tubular CuO x support prepared in Example 9. It can be seen from Figure 16 that the CuO x support presents a tubular morphology.

[0132] Apply the obtained 0.5 wt% Pt / CuO x photothermal catalyst to the photothermal degradation experiment:

[0133] Experimental condition 13: Static reaction, toluene concentration 400 ppm, O 2 concentration 310 mg / L, light intensity 270 mW / cm 2 , and the results are as Figure 17 shown.

[0134] Figure 17 The toluene degradation efficiency and CO x mineralization efficiency of 0.5 wt% Pt / CuO 2 as the catalyst under experimental condition 13. It can be seen from Figure 17 that under the light intensity of 270 mW / cm 2 , when the reaction proceeds for 40 min, the toluene degradation efficiency of the 0.5 wt% Pt / CuO x catalyst is 67%, and the CO 2 mineralization efficiency is 42%.

[0135] Comparative example 1

[0136] Preparation of the catalyst:

[0137] S1. Dissolve 2.1414 g of CoCl 2 ·6H 2 O in 20 mL of deionized water to obtain solution A. Dissolve 6 g of NaOH in 200 mL of deionized water to obtain solution B. Under continuous stirring, slowly add solution B to solution A and let it stand for 3 h. Separate the precipitate from the solution by centrifugation and wash it 3 times with deionized water. Dry the precipitate at 80 °C for 12 h. Finally, calcine it in air at 400 °C for 2 h with a heating rate of 5 °C / min -1 to obtain a CoO x support without morphology;

[0138] S2. Disperse 0.6 g of the CoO x support without morphology in 30 mL of deionized water, then add 7.4 mL of 1 g / L K 2 PtCl 6 solution, stir for 1 h, then add the reducing agent NaBH 4 solution (NaBH 4 / Pt = 5 / 1, molar ratio) and continue to stir for 1 h. Then wash it 6 times alternately with deionized water and absolute ethanol and dry it at 80 °C for 12 h to obtain the catalyst, denoted as 0.5 wt% Pt / CoO x (amorphous) catalyst.

[0139] Figure 18 The microscopic image of the CoO x support without morphology prepared in Comparative example 1. It can be seen from Figure 18It can be seen that CoO x The carrier has no specific morphology.

[0140] The obtained 0.5 wt% Pt / CoO x (amorphous) catalyst was applied to the photothermal degradation experiment:

[0141] Experimental condition 14: Static reaction, toluene concentration 400 ppm, O 2 concentration 310 mg / L, light intensity 200 mW / cm 2 , and the results are as Figure 19 shown.

[0142] Figure 19 For the toluene degradation efficiency and CO x (amorphous) as the catalyst under experimental condition 14. 2 As can be seen from Figure 19 , under the light intensity of 200 mW / cm 2 , for the 0.5 wt% Pt / CoO x (amorphous) catalyst, when the reaction proceeds for 40 min, the toluene degradation efficiency is 38%, and the CO 2 mineralization efficiency is 15%. The performance is far lower than that of the 0.5 wt% Pt / CoO x catalyst prepared in Example 1, proving that the 0.5 wt% Pt / CoO x catalyst utilizes the strong interaction between noble metal nanoparticles and metal oxides to effectively reduce the light intensity required for the overall catalyst.

[0143] Experimental condition 15: Static reaction, toluene concentration 400 ppm, O 2 concentration 310 mg / L, light intensity 270 mW / cm 2 , and the results are as Figure 20 shown.

[0144] Figure 20 For the toluene degradation efficiency and CO x (amorphous) as the catalyst under experimental condition 15. 2 As can be seen from Figure 20 , under the light intensity of 270 mW / cm 2 , for the 0.5 wt% Pt / CoO x (amorphous) catalyst, when the reaction proceeds for 40 min, the toluene degradation efficiency is 69%, and the CO 2 mineralization efficiency is 52%. The performance is far lower than that of the 0.5 wt% Pt / CoO x(Flaky) catalyst, which proves that the flaky structure is more conducive to the generation of the LSPR effect by Pt NPs, thereby improving the photothermal catalytic performance.

[0145] Comparative Example 2

[0146] Preparation of the catalyst:

[0147] S1. Calcinate 10 g of urea in air at 550 °C for 4 h with a heating rate of 5 °C / min -1 , to obtain C 3 N 4 support;

[0148] S2. Disperse 0.6 g of the C 3 N 4 support obtained in step S1 in 30 mL of deionized water. Take 7.4 mL of 1 g / L K 2 PtCl 6 solution and add it to the above solution and stir for 1 h. Then add the reducing agent NaBH 4 solution (NaBH 4 / Pt = 5 / 1, molar ratio) and continue to stir for 1 h. After that, wash it alternately with deionized water and absolute ethanol 6 times and dry it at 80 °C for 12 h to obtain the catalyst, denoted as 0.5 wt% Pt / C 3 N 4 photothermal catalyst.

[0149] Apply the obtained 0.5 wt% Pt / C 3 N 4 photothermal catalyst to the photothermal degradation experiment:

[0150] Experimental condition 16: Static reaction, toluene concentration 400 ppm, O 2 concentration 310 mg / L, light intensity 200 mW / cm 2 , and the results are as Figure 21 shown.

[0151] Figure 21 is the toluene degradation efficiency and CO 3 N 4 mineralization efficiency of the catalyst in Experimental condition 16. It can be seen from 2 that under the light intensity of 200 mW / cm Figure 21 , the 0.5 wt% Pt / C 2 catalyst has almost no catalytic performance when the reaction proceeds for 40 min, which proves that the 0.5 wt% Pt / CoO 3 N 4 catalyst prepared in Example 1 has high photothermal catalytic performance due to the combination of Pt and Co x , and 3 O4 The strong interaction between them, and Pt NPs cannot serve as active sites alone.

[0152] Comparative Example 3

[0153] Preparation of the catalyst:

[0154] S1. Dissolve 7.55 g of Al(NO 3 ) 3 ·9H 2 O, 3.5 g of K 2 SO 4 and 2.5 g of CO(NH 2 ) 2 in 80 mL of deionized water, stir for 30 min, then transfer the obtained mixture to a stainless-steel autoclave and heat-treat it at 180 °C for 3 h. After the reaction is completed, cool the autoclave to room temperature. Wash the precipitate with deionized water and absolute ethanol 6 times respectively, then dry it at 80 °C for 12 h, and finally calcine it in air at 500 °C for 2 h with a heating rate of 5 °C min -1 to obtain the Al 2 O 3 support;

[0155] S2. Disperse 0.6 g of the Al 2 O 3 support prepared in step S1 in 30 mL of deionized water. Take 7.4 mL of 1 g / L K 2 PtCl 6 solution and add it to the above solution and stir for 1 h. Then add the reducing agent NaBH 4 solution (NaBH 4 / Pt = 5 / 1, molar ratio) and continue to stir for 1 h. After that, wash it alternately with deionized water and absolute ethanol 6 times and dry it at 80 °C for 12 h to obtain the catalyst, denoted as 0.5 wt% Pt / Al 2 O 3 photothermal catalyst.

[0156] Apply the obtained 0.5 wt% Pt / Al 2 O 3 photothermal catalyst to the photothermal degradation experiment:

[0157] Experimental condition 17: Static reaction, toluene concentration 400 ppm, O 2 concentration 310 mg / L, light intensity 200 mW / cm 2 , and the results are as Figure 22 shown.

[0158] Figure 22 For 0.5 wt% Pt / Al 2 O3 The toluene degradation efficiency and CO 2 mineralization efficiency of the catalyst under experimental condition 17. It can be seen from Figure 22 that under the light intensity of 200 mW / cm 2 , the 0.5 wt% Pt / Al 2 O 3 catalyst has almost no catalytic performance when the reaction proceeds for 40 min.

[0159] The embodiments described above are only descriptions of the preferred modes of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing a highly dispersed noble metal photothermal catalyst, characterized in that the steps include: The highly dispersed noble metal photothermal catalyst is obtained by using a metal oxide as a carrier and a noble metal salt as a load precursor through reduction treatment; The metal oxide includes rod-shaped MnO x , Nano-sheet CoO x and nanotube CuO x At least one of; The rod-shaped MnO x The preparation steps include: dissolving KMnO4 and MnSO4·H2O in water, stirring for 0.5h, heat treating at 160℃ for 24h, cooling, washing, drying and calcining to obtain rod-shaped MnO x ; The dosage ratio of KMnO4, MnSO4·H2O and water is 1.5g:0.275g:80mL; The nanosheet CoO x The preparation steps include: dissolving Co(NO3)2·6H2O in isopropanol, then adding a sodium carbonate solution with a concentration of 1.0 mol / L, stirring for 0.5 h, heat treating at 160°C for 4 h, cooling, washing, drying, and calcining to obtain nano-sheet CoO x ; The dosage ratio of Co(NO3)2·6H2O and isopropanol is 0.01mol:50mL; the volume ratio of isopropanol and sodium carbonate solution is 5:2; The nanotubular CuO x The preparation steps include: dissolving Cu(NO3)2·3H2O in water, then adding a sodium hydroxide solution with a concentration of 1.5 mol / L, stirring at 80°C for 0.5 h, adding ethylenediamine and ammonia water in sequence, stirring for 0.5 h, washing, drying, and calcining to obtain nanotube CuO x ; The dosage ratio of Cu(NO3)2·3H2O and water is 0.01mol:30mL; the volume ratio of water to sodium hydroxide solution is 6:1; the volume ratio of water, ethylenediamine and ammonia water is 6:2:3; The noble metal salt includes at least one of a soluble salt of Pt, Au, Ag or Pd; The reduction treatment includes gas phase reduction treatment or liquid phase reduction treatment; The gas phase reduction treatment includes H2 reduction or CO reduction; the liquid phase reduction treatment includes NaBH4 reduction, NaH2PO2 reduction or N2H4·H2O reduction.

2. The preparation method according to claim 1, characterized in that: The loading amount of the precious metal in the highly dispersed precious metal photothermal catalyst is 0.25 to 10 wt %.

3. A highly dispersed precious metal photothermal catalyst prepared by the preparation method according to any one of claims 1 to 2.

4. Use of the highly dispersed noble metal photothermal catalyst as claimed in claim 3 in photothermal catalytic oxidation degradation of volatile organic compounds.

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