Fluorinated TiO2 supported photocatalyst for toluene coupling synchronous hydrogen production
By using fluorinated TiO2-supported photocatalysts, the problems of poor stability, low activity and low quantum efficiency in the process of photocatalytic toluene coupling synchronous hydrogen production are solved, and efficient catalytic effect and good cycle stability are achieved.
Patent Information
- Application Number
- CN202510157739.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-13
- Publication Date
- 2025-05-13
AI Technical Summary
In the process of photocatalytic toluene coupling synchronous hydrogen production, traditional photocatalytic toluene coupling have problems such as poor stability, low activity and low quantum efficiency, which limits its application efficiency.
Fluorinated TiO2-supported photocatalyst is used. The catalyst is supported by fluorine-doped TiO2, which is supported by 0.5-5 wt% of precious metals (such as Au, Pt, Pd), and is prepared by hydrothermal method and photodeposition method, which improves the separation of photogenerated carriers and the adsorption and activation of reactants.
The efficiency of photocatalytic toluene coupling synchronous hydrogen production is significantly improved, catalytic activity is improved, and the degree of peroxidation of the product is reduced, with good cycle stability and wide application prospects.
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Figure CN119972038A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a photocatalyst preparation technology and its application field, and in particular to a fluorinated TiO 2 A method for preparing a supported photocatalyst and its application in photocatalytic toluene coupling and simultaneous hydrogen production. Background Art
[0002] As an important chemical raw material, toluene is widely used in many fields, such as chemicals, medicine, spices and food preservatives. However, with the increasingly stringent national environmental protection policies and the saturation of the fuel oil market, it is particularly important to develop high-value processing and utilization methods for toluene. Through high-value conversion technology, toluene can be converted into high-value-added chemicals, such as benzaldehyde, benzyl alcohol, benzoic acid and bibenzyl, which will help improve the economic benefits of enterprises and promote the transformation and upgrading of the refining industry and high-quality development.
[0003] Bibenzyl motifs are commonly found in many natural products and show potential biological and agricultural activities. Some bibenzyl derivatives are used as starting materials for the synthesis of high-value drug molecules. Traditional methods for the synthesis of bibenzyl include the reduction of stilbene / diphenylacetylene derivatives. In recent years, bibenzyl derivatives have been synthesized by homo-coupling using benzyl halides, benzyl magnesium halides and phenylacetic acid. However, these methods require pre-functionalization of the raw materials and harsh reaction conditions, usually requiring the addition of strong oxidants / reducing agents. Therefore, there is an urgent need for an economical, mild and readily available starting material method to synthesize bibenzyl. In this context, photocatalytic technology meets the requirements for bibenzyl production due to its unique advantages (such as no pollution, mild reaction conditions, and abundant and readily available solar energy). At the same time, the generation of bibenzyl using toluene as a raw material can also produce clean energy H 2 , with high atom economy. The key to the simultaneous production of hydrogen by photocatalytic toluene coupling is to construct a stable and efficient photocatalyst.
[0004] Titanium dioxide (TiO 2 ) is a typical semiconductor material, which is widely used in photocatalytic research due to its high stability, non-toxicity, simple synthesis, low cost, and tunable electronic band structure. However, due to the short carrier lifetime, the separation and transport of carriers are poor, which greatly limits the application of photogenerated carriers in photoelectrochemical and chemical reactions. Based on this, the present invention prepares a fluorinated TiO 2 The prepared photocatalyst was used for toluene coupling and simultaneous hydrogen production. Summary of the invention
[0005] The present invention aims to provide a fluorinated TiO2 for photocatalytic toluene coupling and simultaneous hydrogen production. 2A supported photocatalyst and a preparation method thereof, the photocatalyst can effectively promote the separation of photogenerated carriers, improve the adsorption and activation of reactants, and effectively reduce the degree of peroxidation of products, thereby solving the shortcomings of traditional photocatalysts such as poor stability, low activity, and low quantum efficiency. The photocatalyst synthesis method is simple and easy, has good catalytic efficiency, and is conducive to the promotion and application in photocatalytic organic matter conversion reactions.
[0006] To achieve the above object, the present invention is implemented by the following technical solutions: A fluorinated TiO 2 Application of supported photocatalysts in photocatalytic toluene coupling and simultaneous hydrogen production: the fluorinated TiO 2 The carrier of the supported photocatalyst is fluorine-doped TiO 2 The active metal is one of Au, Pt, and Pd, and the loading amount of the active metal accounts for 0.5-5wt% of the carrier; the reaction environment during the photocatalytic toluene coupling and synchronous hydrogen production reaction is an argon atmosphere, and the reaction substrate component is toluene; the light source is UV LED (365 nm, 100 mA, ams-OSRAM); the illumination time is 1 h.
[0007] Preferably, in the photocatalytic toluene coupling simultaneous hydrogen production reaction, the amount of catalyst used is 10 mg; and the reaction substrate component is: 3 mL toluene.
[0008] Preferably, the products of the photocatalytic toluene coupling synchronous hydrogen production reaction include: 1,2-diphenylethane, o-benzyltoluene, p-benzyltoluene and hydrogen.
[0009] Preferably, the fluorinated TiO 2 The preparation method of the supported photocatalyst comprises the following steps: (1) Prepare a 10 M HCl aqueous solution, referred to as solution A. Take 10 mL of solution A and transfer it to a hydrothermal reactor. Add 20 mL of organic solution B containing 0.6 mL of titanium n-butoxide without stirring. Heat at 180 °C for 12 to 24 h. After the reaction is completed, the solid obtained is washed, dried, and ground and named TiO 2 ; (2) Prepare a certain concentration of HF solution, record it as solution C, take 5 mL of solution C and place it in a hydrothermal kettle, then add a certain amount of TiO obtained in step (1) into the hydrothermal kettle. 2 , stir evenly, react at 60 ~ 80 ℃, and control the reaction time. After the reaction, the solid obtained is washed, dried, and ground and named TiO 2 -F; (3) The TiO obtained in step (2) 2-F is dispersed in a mixed solution of deionized water and methanol, and then a noble metal precursor solution is added dropwise thereto, and after continuous stirring, a photo-deposition reduction treatment is performed under an argon atmosphere, and then the obtained precipitate is filtered, washed, and dried to obtain the fluorinated TiO 2 Supported photocatalyst.
[0010] Preferably, the solvent of the organic solution B in step (1) is toluene, hexane or cyclohexane.
[0011] Preferably, the mass percentage concentration of the hydrogen fluoride solution in step (2) is 1 to 10%.
[0012] Preferably, the stirring time in step (2) is 10 to 30 min.
[0013] Preferably, the hydrothermal reaction time in step (2) is 1 h to 8 h.
[0014] Preferably, the solid obtained in step (2) is washed twice with deionized water and dried under vacuum at 60° C. for 12 h.
[0015] Preferably, the noble metal precursor used in step (3) is chloride of the noble metal elements Au, Pt, Pd.
[0016] Preferably, the ratio of the photodeposition solution in step (3) is CH 3 OH:H 2 O = 8 ml:8 ml; light source is UVLED (365nm, 600 mA, ams-OSRAM); illumination duration is 1 h.
[0017] The present invention has the following advantages and beneficial effects: 1. Fluorinated TiO2 prepared by the present invention 2 Supported photocatalysts have low raw material prices and simple preparation processes, and have broad application prospects; 2. Fluorinated TiO synthesized by the present invention 2 The supported photocatalyst has a nanosheet structure, which can promote the full exposure of the active sites of the catalyst, so that the reaction raw materials can fully contact with the active sites of the catalyst. More importantly, due to the large electronegativity of fluorine, it is introduced into TiO 2 The structure can promote the separation of photogenerated carriers and effectively inhibit the recombination of photogenerated electrons and holes, thereby significantly improving the efficiency of photocatalytic toluene coupling and simultaneous hydrogen production. The loading of precious metals provides more active sites for the reaction, effectively improving the adsorption and activation of the reactant toluene. Ultimately, the catalyst exhibits high catalytic activity in the reaction of photocatalytic toluene coupling and simultaneous hydrogen production. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 The TiO 2 、1%Pt / TiO 2 、TiO 2 -F and 1%Pt / TiO 2 -F X-ray diffraction spectrum.
[0019] Figure 2 The TiO 2 、1%Pt / TiO 2 、TiO 2 -F and 1%Pt / TiO 2 -Raman spectrum of F.
[0020] Figure 3 1% Pt / TiO in Example 2 of the present invention 2 -F’s (a) SEM, (b) TEM, (c) HRTEM and (d) EDX-Mapping images.
[0021] Figure 4 The TiO 2 、1%Pt / TiO 2 、TiO 2 -F and 1%Pt / TiO 2 DRS spectrum of -F.
[0022] Figure 5 This is a performance comparison chart of the photocatalytic toluene coupling and synchronous hydrogen production of Example 1-2 of the present invention and Comparative Example 1-2.
[0023] Figure 6 This is a performance comparison chart of photocatalytic toluene coupling and synchronous hydrogen production with different metal contents in Example 2 of the present invention.
[0024] Figure 7 1% Pt / TiO in Example 2 of the present invention 2 -F Cyclic performance diagram of photocatalytic toluene coupling and simultaneous hydrogen production. DETAILED DESCRIPTION
[0025] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is described in detail below in conjunction with embodiments and drawings. The examples described are further explanations of the present invention rather than limitations of the contents of the present invention.
[0026] Example 1 Prepare 10 M HCl aqueous solution and record it as solution A. Take 10 mL of solution A and transfer it to a hydrothermal reactor. Add 20 mL of toluene solution containing 0.6 mL of titanium n-butoxide without stirring. Heat at 180 °C for 12 h. After the reaction is completed, the solid obtained is washed, dried, and ground and named TiO 2 ; 5 mL of HF solution (4.5 wt%) was placed in a hydrothermal reactor, and 100 mg of TiO was added to the hydrothermal reactor. 2 , stirred evenly, reacted at 60 °C for 1 h, and the solid obtained after the reaction was washed, dried, and ground and named TiO 2 -F.
[0027] Example 2 50 mg TiO 2 -F was dispersed in 8 mL of deionized water, and 8 mL of methanol was added. After stirring and dispersing evenly, 132.8 μL of chloroplatinic acid aqueous solution (concentration of 10 mg / mL) was added dropwise, and stirring was continued until the sample was evenly dispersed. Under an argon atmosphere, UV LED (365 nm, 600 mA, ams-OSRAM) was used for photodeposition for 1 h, and the obtained sample was filtered, washed with deionized water, and dried in an oven to obtain 1% Pt / TiO 2 -F.
[0028] Comparative Example 1 Prepare 10 M HCl aqueous solution and record it as solution A. Take 10 mL of solution A and transfer it to the hydrothermal kettle. Add 20 mL of organic solution B containing 0.6 mL of titanium n-butoxide without stirring. Heat the hydrothermal kettle at 180 °C for 24 h. After the reaction is completed, the solid obtained is washed, dried, ground and named TiO 2 .
[0029] Comparative Example 2 50 mg TiO 2 The sample was dispersed in 8 mL of deionized water, and 8 mL of methanol was added. After stirring and dispersing evenly, 132.8 μL of chloroplatinic acid aqueous solution (concentration of 10 mg / mL) was added dropwise, and stirring was continued until the sample was evenly dispersed. Under an argon atmosphere, UV LED (365 nm, 600 mA, ams-OSRAM) was used for photodeposition for 1 h. The obtained sample was filtered, washed with deionized water, and dried in an oven to obtain 1% Pt / TiO 2 .
[0030] X-ray powder diffraction (XRD): The phase characterization of the samples was measured using Panalytical's X'pert pro powder diffractometer, with an X'celerator as the detector, a copper target (Cu Kα, λ = 0.154 nm) as the excitation radiation source, an operating voltage of 45 KV, and an operating current of 40 mA.
[0031] The molecular structure of the sample was determined using the DXR2xi spectrometer from Thermo Scientific, USA, with a scanning range of 100-1800 cm -1 , the excitation light source is 532 nm.
[0032] The morphology of the catalyst was observed by S-4800 field emission scanning electron microscope. The vacuum degree of the analysis chamber was less than 2.7×10 –6 Pa, the scanning voltage and current were 5 kV and 7 μA respectively. The sample powder was glued to the conductive glue and then observed after gold spraying.
[0033] Field emission transmission electron microscopy (TEM): TEM images of the samples were observed on a Tecnai G2 F20 transmission electron microscope (TEM) with an accelerating voltage of 200 KV.
[0034] Figure 1 The TiO 2 、TiO 2 -F, 1%Pt / TiO 2 and 1%Pt / TiO 2 -F X-ray diffraction spectrum. Figure 1 As shown, TiO 2 After fluorination, there is no obvious change in XRD, which proves that fluorination does not change the TiO 2 The crystal structure of 1%Pt / TiO 2 In addition to TiO 2 Except for the diffraction peak of Pt, no characteristic peaks of Pt species were detected.
[0035] Figure 2 The TiO 2 、TiO 2 -F, 1%Pt / TiO 2 and 1%Pt / TiO 2 -F Raman spectrum. Figure 2 As shown, TiO 2 After fluorination, there is no obvious change in Raman, which proves that fluorination does not change TiO 2 The crystal structure of 1%Pt / TiO 2Raman spectrum of -F relative to TiO 2 and TiO 2 -F diffraction peak shifts positively, proving that Pt and TiO 2 There is a strong interaction force.
[0036] Figure 3 1% Pt / TiO in Example 2 of the present invention 2 -F SEM and TEM images. It can be seen from the figure that TiO 2 The morphology of Pt and TiO is square nanosheets, and Pt is nanoparticles. 2 The lattice fringes of the Pt nanoparticles were observed in the mapping spectrum, and the Ti, O and F elements were evenly distributed.
[0037] Figure 4 The TiO 2 、TiO 2 -F, 1%Pt / TiO 2 and 1%Pt / TiO 2 -F DRS spectrum. It can be seen from the figure that fluorination has a great influence on TiO 2 The light absorption of 1%Pt / TiO 2 -F compared to TiO 2 and TiO 2 -F light absorption increased significantly.
[0038] Photocatalytic toluene coupling and simultaneous hydrogen production: 10 mg of catalyst and 3 ml of toluene were placed in a reaction bottle, and Ar was pumped in until O was completely removed. 2 The products were detected after 1 h of UV LED (365 nm, 100 mA, ams-OSRAM) illumination.
[0039] Figure 5 The performance comparison of the photocatalytic toluene coupling and simultaneous hydrogen production of Example 1-2 of the present invention and Comparative Example 1-2 is shown in the figure. 2 -F has the best photocatalytic performance. The liquid product generation rates of its photocatalytic toluene coupling and simultaneous hydrogen production are: the generation rate of 1,2-diphenylethane is 4068 µmol·g -1 ·h -1 ; The generation rate of o-benzyltoluene is 166 µmol·g -1 ·h -1 ; The generation rate of benzyltoluene is 157 µmol·g -1 ·h -1 , and the hydrogen yield was 7464.2 µmol·g -1 ·h-1 , catalytic activity relative to 1% Pt / TiO 2 (The production rate of 1,2-diphenylethane is 92 µmol·g -1 ·h -1 ; The generation rate of o-benzyltoluene is 33 µmol·g -1 ·h -1 ; The generation rate of benzyltoluene is 17 µmol·g -1 ·h -1 , and the hydrogen yield was 1601 µmol·g -1 ·h -1 ) has a high improvement, proving that the fluorination process is beneficial to the simultaneous hydrogen production by photocatalytic toluene coupling.
[0040] Figure 6 This is a performance comparison chart of photocatalytic toluene coupling and simultaneous hydrogen production with different metal contents in Example 2 of the present invention. As shown in the figure, under light irradiation, 1% Pt / TiO 2 -F has the best photocatalytic performance. The liquid product generation rates of its photocatalytic toluene coupling and simultaneous hydrogen production are: the generation rate of 1,2-diphenylethane is 4068 µmol·g -1 ·h -1 ; The generation rate of o-benzyltoluene is 166 µmol·g -1 ·h -1 ; The generation rate of benzyltoluene is 157 µmol·g -1 ·h -1 , and the hydrogen yield was 7464.2 µmol·g -1 ·h -1 .
[0041] Figure 7 1% Pt / TiO in Example 2 of the present invention 2 -F photocatalytic toluene coupling synchronous hydrogen production cycle performance diagram. As can be seen from the figure, 1% Pt / TiO 2 After 5 cycles, the hydrogen production retention rate of -F was still 82%, and the main liquid product retention rate was still above 80%, proving that this catalyst has good cycle performance.
[0042] In summary, the fluorinated TiO prepared by the present invention 2 The supported photocatalyst has good catalytic performance in the toluene coupling simultaneous hydrogen production reaction and has good cycle stability, and has great application potential.
[0043] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.
Claims
1. Application of a fluorinated TiO2-supported photocatalyst in photocatalytic toluene coupling and simultaneous hydrogen production, characterized in that: The carrier of the fluorinated TiO2-loaded photocatalyst is fluorine-doped TiO2, the active metal is one of Au, Pt, and Pd, and the loading amount of the active metal accounts for 0.5-5wt% of the carrier; the reaction environment during the photocatalytic toluene coupling and synchronous hydrogen production reaction is an argon atmosphere, and the reaction substrate component is toluene.
2. The use according to claim 1, characterized in that: In the photocatalytic toluene coupling simultaneous hydrogen production reaction, the catalyst dosage is 10 mg; the reaction substrate component is: 3 mL toluene; the light source is UV LED with a wavelength of 365 nm; and the illumination time is 1 h.
3. The use according to claim 1, characterized in that: The preparation method of the fluorinated TiO2 supported photocatalyst comprises the following steps: (1) Prepare a 10 M HCl aqueous solution, referred to as solution A. Take 10 mL of solution A and transfer it to a hydrothermal reactor. Then add 20 mL of organic solution B containing 0.6 mL of titanium n-butoxide. Heat at 180 °C for 12 to 24 h. After the reaction is completed, the resulting solid is washed, dried, and ground and named TiO2. (2) Prepare a certain concentration of HF solution, record it as solution C, take 5 mL of solution C and place it in a hydrothermal kettle, then add a certain amount of TiO2 obtained in step (1) into the hydrothermal kettle, stir evenly, react at 60 ~ 80 ° C, and control the reaction time. After the reaction is completed, the solid obtained is washed, dried, and ground, and then named TiO2-F; (3) The TiO2-F obtained in step (2) is dispersed in a mixed solution of deionized water and methanol, and then a noble metal precursor solution is added dropwise thereto. After continuous stirring, the mixture is subjected to photoreduction treatment under an argon atmosphere. The obtained precipitate is then filtered, washed, and dried to obtain the fluorinated TiO2-supported photocatalyst.
4. The use according to claim 3, characterized in that: The solvent of the organic solution B in step (1) is toluene, hexane or cyclohexane.
5. The use according to claim 3, characterized in that: The mass percentage concentration of the hydrogen fluoride solution in step (2) is 1 to 10%.
6. The use according to claim 3, characterized in that: The stirring time in step (2) is 10 to 30 min.
7. The use according to claim 3, characterized in that: The hydrothermal reaction time in step (2) is 1 h to 8 h.
8. The use according to claim 3, characterized in that: The solid obtained in step (2) was washed twice with deionized water and dried under vacuum at 60 °C for 12 h.
9. The use according to claim 3, characterized in that: The noble metal precursor used in step (3) is chloride of the noble metal elements Au, Pt, and Pd.
10. The use according to claim 3, characterized in that: In step (3), the ratio of the photodeposition solution is CH3OH:H2O =8 ml:8 ml; the light source of the photodeposition reduction process is a UV LED with a wavelength of 365 nm; and the illumination time is 1 h.