Preparation method of stearic acid modified TiO2 nanocrystal and application of stearic acid modified TiO2 nanocrystal in photocatalytic preparation of H2O2
By modifying stearic acid molecules on the surface of TiO2 nanocrystalline and adjusting the hydrophobic gas-abilizing properties of the composite photocatalyst, the problem of low oxygen utilization in the photocatalytic method is solved, and the H2O2 yield is significantly improved, and it has high commercial application value.
Patent Information
- Application Number
- CN202510021228.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-07
- Publication Date
- 2025-05-30
AI Technical Summary
In the existing photocatalytic methods, the utilization rate of oxygen molecules in liquid phase photocatalytic reaction systems is low, resulting in a low yield of H2O2. Factors include low solubility of oxygen in water and low reaction energy barrier between water molecules and oxygen.
By modifying the stearic acid molecule on the surface of TiO2 nanocrystals, the hydrophobic gas-philicity of the composite photocatalyst surface is adjusted, thereby improving the O2 concentration at the photocatalyst/solution interface and optimizing the 2e-ORR reaction conditions.
The H2O2 yield of TiO2 photocatalyst has been significantly improved to reach 3160μM h-1g-1, which has high commercial application value.
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Figure CN120054450A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of composite photocatalyst preparation and application, and specifically relates to a stearic acid-modified TiO 2 Nanocrystal preparation method and photocatalytic preparation of H 2 O 2 application. Background Art
[0002] Hydrogen peroxide (H 2 O 2 ) is a green oxidant and a new energy carrier for geophysical exploration, and is widely used in the fields of sanitation, sewage treatment, chemical synthesis, energy, etc. 2 O 2 More than 95% of H2O comes from the anthraquinone method, which is energy-intensive, polluting, and expensive. These shortcomings have prompted the search for green, economical, and low-carbon alternatives to the anthraquinone method for preparing H2O. 2 O 2 The method is extremely urgent. Through the photocatalytic two-electron oxygen reduction reaction (2e - ORR) to produce H 2 O 2 It is considered to be a green, environmentally friendly, low-energy and low-cost method. This method uses oxygen molecules and water molecules as reactants, solar energy as the driving energy, and the catalyst is mostly transition metal oxide semiconductor materials. Therefore, it has become one of the most promising methods to replace the anthraquinone method. However, this method is not suitable for preparing H 2 O 2 The yield is low. An important factor affecting the yield is that oxygen molecules, as a reactant, have a very low utilization rate in the liquid phase photocatalytic reaction system. This is mainly because the solubility of oxygen molecules in water is very low (~8 mg / L), and it is difficult for oxygen in the air to reach the photocatalyst / solution interface microenvironment to participate in photocatalysis. - ORR, in addition, the hydrogen evolution reaction (HER) with water molecules as reactants is compared with 2e - ORR has a lower reaction energy barrier, thus increasing the O 2 concentration, balancing water molecules and O 2 The relative concentration of molecules is to increase the photocatalytic 2e - The key to ORR. Summary of the invention
[0003] The present invention provides a stearic acid (SA) modified TiO 2 Composite photocatalyst, by adjusting TiO 2 The crystal surface exposure ratio of nanocrystals optimizes the loading of SA and adjusts the hydrophobicity and aerophilicity of the composite photocatalyst surface, thereby improving the TiO 2Photocatalytic production of H 2 O 2 yield.
[0004] One of the purposes of the present invention is to provide a SA / TiO 2 composite photocatalyst.
[0005] Another purpose of the present invention is to provide a preparation method of the above-mentioned SA / TiO 2 composite photocatalyst. The method is simple to operate, green and environmentally friendly. The surface of the composite photocatalyst has good hydrophobic and gasophilic properties, providing a better catalyst basis for its photocatalytic application.
[0006] The third purpose of the present invention is to provide an application for the SA / TiO 2 composite photocatalyst. The composite photocatalyst provided by the present invention enables TiO 2 to achieve a significant increase in the photocatalytic production of H 2 O 2 yield without loading a cocatalyst and without changing the original crystal structure of the material.
[0007] The technical solution adopted by the present invention is as follows:
[0008] A SA / TiO 2 composite photocatalyst, comprising the following components by mass fraction:
[0009] 1.00% - 10.00% stearic acid loading;
[0010] 90.00% - 99.00% TiO 2 nanocrystalline photocatalyst.
[0011] The two ends of the stearic acid molecule (SA) are respectively a carboxyl group and a long carbon chain alkyl group. Among them, due to the high symmetry of the alkyl charge distribution, it has significant non-polar molecular characteristics. The carboxyl group at the other end is easy to form an ester bond with the adsorbed hydroxyl group on the surface of TiO 2 and is thus easily adsorbed stably with TiO 2 to change the hydrophilic-hydrophobic and gasophilic properties of the surface of pure TiO 2 . Based on this, the SA-modified TiO 2 composite photocatalyst designed by the present invention has the characteristics of adjustable hydrophobicity and gasophilicity, and significantly improves its photocatalytic production of H 2 O 2 performance.
[0012] As a preferred technical solution, the loading amount of SA molecules is 3.93%.
[0013] The present invention also provides a preparation method of the SA / TiO 2 composite photocatalyst, comprising the following steps:
[0014] a) TiO 2 Preparation of nanocrystals: Using tetrabutyl titanate as the precursor, hydrofluoric acid as the capping agent, and hydrochloric acid as the hydrolysis inhibitor, a hydrothermal reaction solution was prepared. By adjusting the amount of the capping agent, the exposure ratio of the (001) crystal plane of TiO 2 nanocrystals was adjusted. After the hydrothermal reaction was completed, TiO 2 nanocrystals with different exposed crystal planes were obtained through centrifugation, washing, and drying. Then, the residual F ions on the surface of the nanocrystals were removed by high-temperature calcination. According to the added volume of hydrofluoric acid, the prepared TiO 2 nanocrystals were labeled as TiO 2 -xHF.
[0015] b) Preparation of SA-modified TiO by the oil bath method 2 Photocatalyst: The TiO 2 -xHF nanocrystals prepared in step a) and a certain amount of SA were added to acetone to prepare an oil bath reaction solution. Through the oil bath reaction, SA molecules underwent a surface chemical reaction with TiO 2 to form stable ester bonds and were thus loaded on the surface of TiO 2 surface. The SA-modified TiO 2 composite photocatalyst was obtained through centrifugation, washing, and drying. According to the concentration of the SA solution used in the oil bath reaction, the composite photocatalyst was labeled as TiO 2 -xHF-ySA.
[0016] Continuing with the above scheme, specifically, the process of preparing the hydrothermal solution in step a) is as follows: Measure 25.0 mL of tetrabutyl titanate and add it to a 100.0 mL polytetrafluoroethylene hydrothermal autoclave. Add 1.00 - 3.00 mL of deionized water and 1.00 - 3.00 mL of a 40.0 wt.% hydrofluoric acid aqueous solution thereto, then add 0.5 mL of concentrated hydrochloric acid, and stir evenly with a plastic rod for later use.
[0017] Preferably, in step a), the amount of deionized water used is 1.00 mL, and the amount of hydrofluoric acid used is 3.00 mL.
[0018] Continuing with the above scheme, in step a), the hydrothermal temperature is 120 - 200 °C, and the hydrothermal time is 24 h.
[0019] Preferably, in step a), the hydrothermal temperature is 180 °C.
[0020] Continuing with the above scheme, in step a), when centrifuging to collect the hydrothermal product, a solution with a volume ratio of ethanol to deionized water of 1:1 is used as the cleaning solution. The centrifugation speed is 10,000 revolutions, the centrifugation time is 10 min, and this is repeated three times. Then, the centrifuged and washed product is transferred to an oven and dried at a temperature of 80 °C for 6 h.
[0021] Following the above scheme, the high temperature calcination in step a) is carried out in a muffle furnace, the heating rate is 10° C. / min, the calcination temperature is 550° C., and the time is 2 h.
[0022] Following the above scheme, in step b), the precursor solution of the oil bath reaction is composed of the TiO prepared in step a). 2 -xHF nanocrystals 500.0 mg, 50 mL SA acetone solution, the solution concentration is 1.0-6.0 mM, fully stirred for 30 min to obtain a suspension solution, and then transferred to an oil bath pot and reacted at 60-100 ° C for 2-10 h.
[0023] Preferably, in step b), the concentration of the SA acetone solution is 4.0 mM, the oil bath reaction temperature is 80° C., and the reaction time is 6 h.
[0024] Following the above scheme, in step b), washing is performed using a solution of acetone and ethanol in a volume ratio of 1:1, and drying is performed in an oven at 60° C. for 12 h.
[0025] Compared with the prior art, the present invention has the following beneficial effects:
[0026] The present invention adopts the method of 2 The surface of nanocrystals is modified with stearic acid molecules, which significantly changes the hydrophobicity and aerophilicity of the photocatalyst / solution interface, thereby significantly improving the photocatalytic 2e - ORR to produce H 2 O 2 The prepared composite photocatalyst has better performance than the original TiO 2 The photocatalyst showed higher visible light photocatalytic efficiency in the production of H 2 O 2 The yield can reach 3160 μM h -1 g -1 , which has high value for large-scale commercial applications. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 SA modified TiO prepared in Examples 1-4 and 6 of the present invention 2 Composite photocatalyst and TiO 2 X-ray diffraction pattern (XRD) of nanocrystals;
[0028] Figure 2 This is a transmission electron microscope image of Example 3 of the present invention; a and b represent different transmission magnifications;
[0029] Figure 3 Fourier transform infrared spectra (a) and contact angle test performance diagram (b) of the samples prepared in Examples 1-4 and Example 6;
[0030] Figure 4 For Comparative Example 1, the contact angle test performance diagram of the composite photocatalyst obtained by the steps of loading stearic acid in Example 5 and Example 6 according to Example 3;
[0031] Figure 5 For the photocatalytic preparation of H 2 O 2 Performance diagram of the composite photocatalyst prepared in Examples 1-6 and Comparative Example 1. Detailed implementation mode
[0032] Next, in combination with the embodiments of the present invention, the technical solutions of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention. The test methods used in the embodiments of the present invention are all conventional methods unless otherwise specified; the materials, reagents, etc. used are reagents and materials that can be obtained from commercial channels unless otherwise specified.
[0033] Example 1
[0034] This example provides the preparation of SA-modified TiO 2 Composite photocatalyst, and its preparation method includes the following steps:
[0035] a) Preparation of TiO 2 Nanocrystals: Measure 25.0 mL of tetrabutyl titanate and add it to a 100.0 mL polytetrafluoroethylene hydrothermal autoclave. Add 1.00 mL of deionized water and 3.00 mL of a 40.0 wt.% hydrofluoric acid aqueous solution thereto, and then add 0.5 mL of concentrated hydrochloric acid. Stir evenly with a plastic rod; then transfer the above suspension to an oven and react at 180 °C for 24 h; collect the reaction product by centrifugation. The hydrothermal product collected by centrifugation uses a solution with a volume ratio of ethanol to deionized water of 1:1 as the cleaning solution, the centrifugation speed is 10,000 revolutions, the centrifugation time is 10 min, and repeat three times. Then transfer the centrifuged and washed product to an oven and dry at 80 °C for 6 h; place the above sample in a muffle furnace for high-temperature calcination, the heating rate is 10 °C / min, the calcination temperature is 550 °C, and the time is 2 h.
[0036] b) Preparation of SA-modified TiO 2 Photocatalyst by oil bath method: The TiO prepared above 2500.0 mg of nanocrystals and 50 mL of a 1.0 mM SA acetone solution were stirred thoroughly for 30 min to obtain a suspension, which was then transferred to an oil bath and reacted at 80 °C for 6 h. The product obtained from the oil bath reaction was centrifuged, and then the product of the oil bath reaction was washed with a solution of acetone and ethanol in a volume ratio of 1:1. Drying was carried out in an oven at 60 °C for 12 h.
[0037] Example 2
[0038] This example provides the preparation of SA-modified TiO 2 composite photocatalyst, and its preparation method includes the following steps:
[0039] a) Preparation of TiO 2 nanocrystals: Measure 25.0 mL of tetrabutyl titanate and add it to a 100.0 mL polytetrafluoroethylene hydrothermal autoclave. Add 1.00 mL of deionized water and 3.00 mL of a 40.0 wt.% hydrofluoric acid aqueous solution to it, then add 0.5 mL of concentrated hydrochloric acid, and stir evenly with a plastic rod; then transfer the above suspension to an oven and react at 180 °C for 24 h; collect the reaction sample by centrifugation. The hydrothermal product collected by centrifugation is washed with a solution of ethanol and deionized water in a volume ratio of 1:1 as the cleaning solution. The centrifugation speed is 10,000 revolutions, and the centrifugation time is 10 min. Repeat three times, and then transfer the centrifuged and washed product to an oven and dry at 80 °C for 6 h; place the above sample in a muffle furnace for high-temperature calcination, with a heating rate of 10 °C / min, a calcination temperature of 550 °C, and a time of 2 h.
[0040] b) Preparation of SA-modified TiO 2 photocatalyst by oil bath method: The above-prepared TiO 2 nanocrystals (500.0 mg) and 50 mL of a 2.0 mM SA acetone solution were stirred thoroughly for 30 min to obtain a suspension, which was then transferred to an oil bath and reacted at 80 °C for 6 h. The product obtained from the oil bath reaction was centrifuged, and then the product of the oil bath reaction was washed with a solution of acetone and ethanol in a volume ratio of 1:1. Drying was carried out in an oven at 60 °C for 12 h.
[0041] Example 3
[0042] This example provides the preparation of SA-modified TiO 2 composite photocatalyst, and its preparation method includes the following steps:
[0043] a) TiO 2Preparation of nanocrystals: Measure 25.0 mL of tetrabutyl titanate and add it to a 100.0 mL polytetrafluoroethylene hydrothermal autoclave. Add 1.00 mL of deionized water and 3.00 mL of hydrofluoric acid aqueous solution with a concentration of 40.0 wt.%, then add 0.5 mL of concentrated hydrochloric acid, and stir evenly with a plastic rod. Subsequently, transfer the above suspension to an oven and react at 180 °C for 24 h. Collect the reacted sample by centrifugation. The hydrothermal product collected by centrifugation uses a solution with a volume ratio of ethanol to deionized water of 1:1 as the cleaning solution, with a centrifugation speed of 10,000 rpm and a centrifugation time of 10 min. Repeat three times, and then transfer the centrifugally washed product to an oven and dry at 80 °C for 6 h. Place the above sample in a muffle furnace for high-temperature calcination, with a heating rate of 10 °C / min, a calcination temperature of 550 °C, and a time of 2 h.
[0044] b) Preparation of SA-modified TiO by oil bath method 2 Photocatalyst: Stir 500.0 mg of the above-prepared TiO 2 nanocrystals and 50 mL of a 4.0 mM SA acetone solution for 30 min to obtain a suspension solution, and then transfer it to an oil bath pot and react at 80 °C for 6 h. Centrifuge to obtain the product of the oil bath reaction. Subsequently, wash the product of the oil bath reaction with a solution with a volume ratio of acetone to ethanol of 1:1, and dry in an oven at 60 °C for 12 h.
[0045] Example 4
[0046] This example provides the preparation of SA-modified TiO 2 composite photocatalyst, and its preparation method includes the following steps:
[0047] a) TiO 2 Preparation of nanocrystals: Measure 25.0 mL of tetrabutyl titanate and add it to a 100.0 mL polytetrafluoroethylene hydrothermal autoclave. Add 1.00 mL of deionized water and 3.00 mL of hydrofluoric acid aqueous solution with a concentration of 40.0 wt.%, then add 0.5 mL of concentrated hydrochloric acid, and stir evenly with a plastic rod. Subsequently, transfer the above suspension to an oven and react at 180 °C for 24 h. Collect the reacted sample by centrifugation. The hydrothermal product collected by centrifugation uses a solution with a volume ratio of ethanol to deionized water of 1:1 as the cleaning solution, with a centrifugation speed of 10,000 rpm and a centrifugation time of 10 min. Repeat three times, and then transfer the centrifugally washed product to an oven and dry at 80 °C for 6 h. Place the above sample in a muffle furnace for high-temperature calcination, with a heating rate of 10 °C / min, a calcination temperature of 550 °C, and a time of 2 h.
[0048] b) Preparation of SA-modified TiO by oil bath method 2 Photocatalyst: Stir the above-prepared TiO 2500.0 mg of nanocrystals and 50 mL of a 6.0 mM SA acetone solution were stirred thoroughly for 30 min to obtain a suspension, which was then transferred to an oil bath and reacted at 80 °C for 6 h. The product obtained from the oil bath reaction was centrifuged, and then the product of the oil bath reaction was washed with a solution having a volume ratio of acetone to ethanol of 1:1. Drying was carried out in an oven at 60 °C for 12 h.
[0049] Example 5
[0050] In this example, TiO 2 Preparation of a composite photocatalyst, the preparation method comprising the following steps:
[0051] TiO 2 Preparation of nanocrystals: 25.0 mL of tetrabutyl titanate was measured and added to a 100.0 mL polytetrafluoroethylene hydrothermal autoclave. 3.00 mL of deionized water and 1.00 mL of a 40.0 wt.% hydrofluoric acid aqueous solution were added thereto, and then 0.5 mL of concentrated hydrochloric acid was added, and the mixture was stirred evenly with a plastic rod; then the above suspension was transferred to an oven and reacted at 180 °C for 24 h; the reaction product was collected by centrifugation. The hydrothermal product collected by centrifugation was washed with a solution having a volume ratio of ethanol to deionized water of 1:1 as a cleaning solution, the centrifugation speed was 10,000 rpm, the centrifugation time was 10 min, and this was repeated three times. Then the centrifugally washed product was transferred to an oven and dried at 80 °C for 6 h; the above sample was placed in a muffle furnace and calcined at a high temperature, the heating rate was 10 °C / min, the calcination temperature was 550 °C, and the time was 2 h.
[0052] Example 6
[0053] In this example, TiO 2 Preparation of a composite photocatalyst, the preparation method comprising the following steps:
[0054] TiO 2 Preparation of nanocrystals: 25.0 mL of tetrabutyl titanate was measured and added to a 100.0 mL polytetrafluoroethylene hydrothermal autoclave. 1.00 mL of deionized water and 3.00 mL of a 40.0 wt.% hydrofluoric acid aqueous solution were added thereto, and then 0.5 mL of concentrated hydrochloric acid was added, and the mixture was stirred evenly with a plastic rod; then the above suspension was transferred to an oven and reacted at 180 °C for 24 h; the reaction product was collected by centrifugation. The hydrothermal product collected by centrifugation was washed with a solution having a volume ratio of ethanol to deionized water of 1:1 as a cleaning solution, the centrifugation speed was 10,000 rpm, the centrifugation time was 10 min, and this was repeated three times. Then the centrifugally washed product was transferred to an oven and dried at 80 °C for 6 h; the above sample was placed in a muffle furnace and calcined at a high temperature, the heating rate was 10 °C / min, the calcination temperature was 550 °C, and the time was 2 h.
[0055] Comparative Example 1
[0056] This comparative TiO 2 Preparation of a composite photocatalyst, the preparation method comprising the following steps:
[0057] TiO 2 Preparation of TiO nanocrystals: Measure 25.0 mL of tetrabutyl titanate and add it to a 100.0 mL polytetrafluoroethylene hydrothermal autoclave. Add 4.00 mL of deionized water thereto, then add 0.5 mL of concentrated hydrochloric acid, and stir evenly with a plastic rod; subsequently, transfer the above suspension to an oven and react at 180 °C for 24 h; collect the reacted sample by centrifugation. The hydrothermal product collected by centrifugation uses a solution with a volume ratio of ethanol to deionized water of 1:1 as the cleaning solution, the centrifugation speed is 10,000 revolutions, the centrifugation time is 10 min, repeat three times, and then transfer the centrifugally washed product to an oven and dry at 80 °C for 6 h; place the above sample in a muffle furnace for high-temperature calcination, the heating rate is 10 °C / min, the calcination temperature is 550 °C, and the time is 2 h.
[0058] Performance testing
[0059] Such as Figure 1 , for the XRD of the samples prepared in Examples 1-4 and Example 6, all samples show a typical rutile phase TiO 2 crystal phase, with obvious characteristic peaks at 25.3 °, 37.8 °, 48.0 ° and 55.1 °, corresponding to the (101), (004), (200) and (211) crystal planes of TiO 2 (PDF: 21-1272). It can be seen from the peak intensity that the samples modified with SA and those before modification both have strong diffraction peaks, indicating that the SA modification does not change the TiO 2 crystal structure.
[0060] Such as Figure 2 , for the TEM images of Example 3 at different magnifications, it can be seen that the sample is in the form of nanosheets, with dimensions in the range of 20-50 nm and a thickness within 10 nm. The smaller size and thickness also provide the possibility for obtaining good performance in the photocatalytic reaction.
[0061] Such as Figure 3 , for the Fourier transform infrared spectra and contact angle test performance diagrams of the samples prepared in Examples 1-4 and Example 6. It can be seen from the figure that the samples modified with SA (Examples 1-4) have significant characteristic peaks at 2850, 2917 and 2956 in the Fourier transform infrared spectra compared with the unmodified samples (Example 6), corresponding to the symmetric, asymmetric vibration modes of C-H in -CH 2 - and -CH 3The asymmetric vibration mode of C-H; the contact angle test surface. As the SA-modified samples show hydrophobic properties, and with the increase in the amount of SA modification, the hydrophobicity is enhanced.
[0062] As Figure 4 , the water contact angle test of the samples prepared in Comparative Example 1 and Examples 5-6 after loading SA according to the method of Example 3 shows that Example 6 exhibits the largest water contact angle, Example 5 is the second, and Comparative Example 1 is the smallest. This indicates that with the increase in the volume of hydrofluoric acid added, the exposure ratio of the (001) crystal plane of TiO 2 nanocrystals is larger, and more hydrophobic SA molecules are loaded, thus obtaining stronger hydrophobic performance.
[0063] In the present invention, the test process of photocatalytic generation of H 2 O 2 is as follows:
[0064] Weigh 50.0 mg of the photocatalyst and add it to a 100.0 mL photocatalytic reactor. Then add the reaction solution to the reactor. The reaction solution is composed of 3.00 mL of isopropanol and 47.00 mL of deionized water. At the same time, adjust the pH to 3.0 with dilute perchloric acid. The above-obtained suspension is ultrasonically treated for 30 min and purged with pure oxygen for 30 min before the photocatalytic reaction, with a flow rate of 20.0 mL min -1 . The photocatalytic reaction is carried out in a water bath, maintaining the temperature of the water bath at 25 °C. Using a 300 W xenon lamp as the light source, the light intensity is adjusted to 100 mW cm -2 , and the concentration of H 2 O 2 is measured by spectrophotometry.
[0065] As Figure 5 , it is the photocatalytic H 2 O 2 preparation performance diagram of the composite photocatalysts prepared in Examples 1-6 and Comparative Example 1. Among them, with the increase in the amount of hydrofluoric acid used in the hydrothermal process, the photocatalytic H 2 O 2 preparation performance of TiO 2 gradually increases. And with the increase in the amount of SA modification, the photocatalytic H 2 O 2 production rate of the SA-modified TiO 2 samples first increases and then decreases. The highest H 2 O 2 production rate is 3160 μM h -1 g -1 , which is because with the increase in the SA loading amount, the O 2 concentration at the interface between the TiO 2 photocatalyst and the solution gradually increases, while the water molecule concentration gradually decreases, resulting in 2e -The ORR reaction performance is improved. As the SA modification amount is further increased, it becomes difficult for water molecules to reach the TiO 2 at the interface between the photocatalyst and the solution, thus reducing the 2e - ORR reaction rate.
[0066] As can be seen from the above, the method for preparing the SA-modified TiO 2 composite photocatalyst of the present invention is simple and easy to implement, realizes the controllable adjustment of the hydrophobic and gasophilic properties at the photocatalyst / solution interface, and thus significantly improves the 2e 2 of the TiO photocatalyst - ORR to produce H 2 O 2 yield. This invention provides material support for the further realization of the green and economical preparation of H 2 O 2 .
[0067] Obviously, the specific implementation schemes described above only further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above is only a specific example of the present invention and is not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.
Claims
1. A stearic acid-modified TiO2 composite photocatalyst, characterized in that: The following components are included in percentage by mass: 1.00%~10.00% stearic acid; 90.00%~99.00%TiO2 nanocrystals.
2. The stearic acid-modified TiO2 composite photocatalyst according to claim 1, characterized in that: The mass percentage of stearic acid is 3.93%.
3. A method for preparing the stearic acid-modified TiO2 composite photocatalyst according to claim 1, characterized in that: The steps include: S1. Preparation of TiO2 nanocrystals by water bath method; S2. Mix the TiO2 nanocrystals and stearic acid in step S1 using an oil bath method.
4. The method for preparing the stearic acid-modified TiO2 composite photocatalyst according to claim 3, characterized in that: In step S1, TiO2 nanocrystals are prepared as follows: a hydrothermal reaction solution is prepared using tetrabutyl titanate as a precursor, hydrofluoric acid as a capping agent, and hydrochloric acid as a hydrolysis inhibitor. After the hydrothermal reaction is completed, TiO2 nanocrystals with different crystal faces exposed are obtained by centrifugation, washing, and drying. The residual F ions on the surface of the nanocrystals are then removed by high-temperature calcination. The volume x of hydrofluoric acid added is adjusted to be between 0 and 5 mL and greater than 0. The prepared TiO2 nanocrystals are marked as TiO2-xHF.
5. The method for preparing the stearic acid-modified TiO2 composite photocatalyst according to claim 4, characterized in that: The processing in step S2 is as follows: the TiO2-xHF nanocrystals and stearic acid prepared in step S1 are added to acetone for oil bath reaction, and then the SA-modified TiO2 composite photocatalyst is obtained by centrifugation, washing and drying. The composite photocatalyst is labeled as TiO2-xHF-ySA according to the concentration of the stearic acid solution used in the oil bath reaction, where the concentration of y is 1-8 mmol / L.
6. The preparation method according to claim 4, characterized in that: The preparation process of the hydrothermal reaction solution in step S1 is as follows: 25.0 mL of tetrabutyl titanate is measured, 1.00-3.00 mL of water and 1.00-3.00 mL of a 40.0 wt. % hydrofluoric acid aqueous solution are added, and then 0.5 mL of concentrated hydrochloric acid is added and stirred evenly.
7. The preparation method according to claim 6, characterized in that: The hydrothermal temperature in step S1 is 120-200° C., and the hydrothermal time is 24 hours; the high-temperature calcination in step S1 is carried out in a muffle furnace, the heating rate is 10° C. / min, the calcination temperature is 550° C., and the time is 2 hours.
8. The preparation method according to claim 5, characterized in that: The precursor solution for the oil bath reaction in step S2 is composed of a mixture of the TiO2-xHF nanocrystals prepared in step S1 and an acetone solution of stearic acid to obtain a solution concentration of 1.0-6.0 mM, which is fully stirred to obtain a suspension solution, which is then transferred to an oil bath pot and reacted at 60-100° C. for 2-10 hours.
9. Application of the stearic acid modified TiO2 composite photocatalyst according to claim 1 in the field of photocatalysis.
10. The use according to claim 9, characterized in that: The stearic acid-modified TiO2 composite photocatalyst is used for photocatalytic production of H2O2.