In-situ prepared TiO2at-ZnFe2O4 composite oxide catalyst and preparation method and application thereof
By preparing TiO2@ZnFe2O4 composite oxide catalysts in situ, the problems of high recombination rate of photogenerated carriers and low visible light utilization rate of TiO2 and ZnFe2O4 semiconductor materials in the field of photocatalysis were solved, and efficient photocatalytic degradation of organic pollutants and hydrogen production performance were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANCHANG HANGKONG UNIVERSITY
- Filing Date
- 2026-03-17
- Publication Date
- 2026-05-19
AI Technical Summary
Existing TiO2 and ZnFe2O4 semiconductor materials suffer from high recombination rates of photogenerated carriers and low utilization of visible light in the field of photocatalysis, resulting in insufficient catalytic activity.
TiO2@ZnFe2O4 composite oxide catalysts were prepared by reverse precipitation and H2 reduction to form an np-type heterojunction. The synergistic effect of ZnFe2O4 support and TiO2 component was utilized to provide more reactive sites and promote the effective separation of photogenerated electron-hole pairs.
It significantly improves the photocatalytic activity and visible light absorption efficiency of the catalyst, enabling rapid and complete degradation of organic pollutants, and exhibits excellent performance in the field of photocatalytic hydrogen production.
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Figure CN122057519A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to an in-situ preparation method and application of TiO2@ZnFe2O4 composite oxide catalyst, belonging to the fields of photodegradation materials for organic pollutants and water pollution control technology. Background Technology
[0002] In recent years, environmental and energy crises have constantly threatened human survival and development. Development models that sacrifice the environment have led to severe environmental burdens and overexploitation of energy, resulting in increasingly serious environmental problems and the emergence of various pollutants. Since the 1980s, scientists have discovered that single-crystal titanium dioxide (TiO2) can split water under ultraviolet light irradiation to produce hydrogen (H2) and oxygen (O2). Research on the degradation of organic pollutants and the splitting of water to produce hydrogen using semiconductor catalysts under light irradiation has attracted the interest of scientists worldwide, and photocatalysis has become a hot topic in scientific research in recent years.
[0003] Ferrates are not only inexpensive and widely available, but also possess superior physical and chemical properties, leading to their widespread application in numerous fields. ZnFe₂O₄, a p-type semiconductor, has a narrow band gap of only 1.9 eV and is sensitive to visible light, but its photocatalytic activity is extremely low due to its high recombination rate of photogenerated carriers. TiO₂, an n-type semiconductor, is one of the most classic representative materials, favored by scientists for its non-toxicity, chemical stability, good biocompatibility, fast electron migration rate, and high photogenerated carrier transport efficiency. However, its relatively large band gap of approximately 3.2 eV limits its absorption of only a small portion of ultraviolet light, resulting in extremely low solar energy utilization. Therefore, constructing an np-type TiO₂@ZnFe₂O₄ heterojunction fully integrates the advantages of both materials, avoids their disadvantages, and improves the photocatalytic activity and visible light absorption efficiency. Summary of the Invention
[0004] To address the problems existing in the prior art, this invention provides an in-situ preparation method and application of TiO2@ZnFe2O4 composite oxide catalyst.
[0005] The present invention is achieved by the following scheme: an in-situ preparation of TiO2@ZnFe2O4 composite oxide catalyst, characterized in that it is prepared by reverse precipitation and H2 reduction of 0.2-0.4 mol zinc chloride, 0.4-0.8 mol ferric chloride, 0.05-0.1 mol tetrabutyl titanate, and 1-2 mol / L ammonia aqueous solution.
[0006] Furthermore, the composition of the TiO2@ZnFe2O4 composite oxide catalyst is represented as NS@NR(x:y), where x and y represent the molar ratio of TiO2 to ZnFe2O4, and x:y = 1:4.
[0007] Furthermore, this includes the following steps:
[0008] Step (1): Weigh 0.2-0.4 mol of zinc chloride and 0.4-0.8 mol of ferric chloride, and dissolve them in 100 mL of deionized water. Stir at room temperature for 30-60 min to obtain a clear solution for later use.
[0009] Step (2): Weigh 0.05-0.1 mol of tetrabutyl titanate and disperse it in anhydrous ethanol. Stir for 10-20 min at room temperature to obtain a solution for later use.
[0010] Step (3): Weigh an appropriate amount of ammonia water and prepare an ammonia water solution with a concentration of 1-2 mol / L, and set aside for later use;
[0011] Step (4): Add the clear solution obtained in steps (1) and (2) dropwise to the solution prepared in step (3), stir for a certain period of time, and set aside for later use;
[0012] Step (5): Take the reaction solution obtained in step (4), filter, wash, and dry it, and then calcine it in a muffle furnace to obtain TiO2@ZnFe2O4 composite oxide;
[0013] Step (6): Place the mixture obtained in step (5) in a tube furnace and pre-treat it with an atmosphere to obtain the desired TiO2@ZnFe2O4 composite oxide with defects.
[0014] Further, in step (5), the reaction solution obtained in step (4) is filtered, washed, dried at 120°C for 12-24 hours, and then placed in a muffle furnace and calcined at 500°C for 4-8 hours to obtain TiO2@ZnFe2O4 oxide.
[0015] Furthermore, in step (6), the mixture obtained in step (5) is placed in a tube furnace and pretreated at 200-400℃ for 1-2 hours in a 1-5% H2 atmosphere to obtain the desired TiO2@ZnFe2O4 composite oxide.
[0016] 1. Further, the following steps are included: 50 mg of defective TiO2@ZnFe2O4 heterojunction material is added to a MO solution (50 ml, 10 ppm). The powdered catalyst is dispersed by sonication. The mixture is placed in a dark environment and magnetically stirred for 30 min until the catalyst and MO reach adsorption-desorption equilibrium. A sample solution is taken out and its concentration is recorded as C0. Then, the mixture is placed under a xenon lamp illuminator to simulate visible light for 120 min. Samples are taken every 20 min to test the concentration, which is recorded as C0. tAll samples were placed in a dark environment, with 3 ml taken each time. Each sampling was performed in a dark room to collect the supernatant, with a sample volume of approximately 3 ml. The absorbance of the target substance after photocatalytic degradation was measured using a UV-Vis spectrophotometer (752N).
[0017] Furthermore, it not only has broad applications in the photocatalytic degradation of organic pollutants, where it can completely degrade all organic pollutants in a short time, but it also has great potential in the field of photocatalytic hydrogen production.
[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0019] This invention relates to the application of an in-situ prepared TiO2@ZnFe2O4 composite oxide catalyst, prepared via reverse precipitation and H2 reduction. The synergistic effect between the ZnFe2O4 composite support and the TiO2 component enhances the catalyst's activity to a certain extent. The heterojunction with defect sites provides more reactive sites, and the quantum tunneling effect of ZnFe2O4 ensures effective separation of photogenerated electron-hole pairs, thus influencing its photocatalytic activity. Compared to untreated TiO2@ZnFe2O4, it exhibits better performance in photocatalytic degradation of organic matter, photocatalytic hydrogen production, and photocurrent. Attached Figure Description
[0020] Figure 1 The above are XRD comparison images of the catalysts prepared in Examples 1-3 and Comparative Examples 1-2 of the present invention.
[0021] Figure 2 The figures show the degradation of methyl orange by the catalysts prepared in Examples 1-3 and Comparative Examples 1-2 of the present invention.
[0022] Figure 3 The catalyst prepared in Example 1 of this invention has a continuous operation stability diagram. Detailed Implementation
[0023] The following is combined Figure 1-3 The present invention will be further described, but the scope of protection of the present invention is not limited to the contents described herein.
[0024] For clarity, not all features of the actual embodiments will be described. In the following description, well-known functions and structures will not be described in detail, as they would confuse the invention with unnecessary details. It should be understood that in the development of any actual embodiment, a great deal of implementation detail must be made to achieve the developer’s specific goals, such as changing one embodiment to another according to the limitations of the system or business. In addition, it should be understood that such development work may be complex and time-consuming, but is merely routine work for those skilled in the art.
[0025] An in-situ preparation method for TiO2@ZnFe2O4 composite oxide catalyst is disclosed, comprising 0.2-0.4 mol zinc chloride, 0.4-0.8 mol ferric chloride, 0.05-0.1 mol tetrabutyl titanate, and 1-2 mol / L ammonia aqueous solution via reverse precipitation and H2 reduction. The composition of the TiO2@ZnFe2O4 composite oxide catalyst is represented as TiO2@ZnFe2O4(x:y), where x and y represent the molar ratio of TiO2 to ZnFe2O4, and x:y = 1:4.
[0026] A method for preparing a titanium-modified Pd-Pt / CeO2 composite oxide catalyst includes the following steps:
[0027] Step (1): Weigh 0.2-0.4 mol of zinc chloride and 0.4-0.8 mol of ferric chloride, and dissolve them in 100 mL of deionized water. Stir at room temperature for 30-60 min to obtain a clear solution for later use.
[0028] Step (2): Weigh 0.05-0.1 mol of tetrabutyl titanate and disperse it in anhydrous ethanol. Stir for 10-20 min at room temperature to obtain a solution for later use.
[0029] Step (3): Weigh an appropriate amount of ammonia water and prepare an ammonia water solution with a concentration of 1-2 mol / L, and set aside for later use;
[0030] Step (4): Add the clear solution obtained in steps (1) and (2) dropwise to the solution prepared in step (3), stir for a certain period of time, and set aside for later use;
[0031] Step (5): Take the reaction solution obtained in step (4) and filter it. Wash the solution pH to 7, dry it at 120℃ for 12-24h, grind it for 30-60min, and then put it into a muffle furnace and calcine it at 500℃ for 4-8h to obtain TiO2@ZnFe2O4 composite oxide.
[0032] Step (6): Place the mixture obtained in step (5) in a tube furnace and pretreat it at 300°C for 1-2 hours in a 1-5% H2 atmosphere to obtain the desired TiO2@ZnFe2O4 composite oxide.
[0033] The defective TiO2@ZnFe2O4 composite oxide prepared in this invention is mainly used in the field of photocatalytic degradation of organic pollutants.
[0034] Example 1
[0035] Preparation of TiO2@ZnFe2O4 (1:4-200℃) composite oxide catalyst
[0036] a) Weigh 0.2 mol of zinc chloride and 0.4 mol of ferric chloride, and dissolve them in 50 mL of deionized water. Stir at room temperature for 30 min. Then, gradually add the resulting clear mixed solution and 0.05 mol of tetrabutyl titanate to 100 mL of 2 mol / L ammonia solution, and continue stirring for 2 h.
[0037] b) The solid obtained in step (a) was filtered and washed with excess deionized water and ethanol until the pH of the solution dropped to 7. The solid was then dried at 120°C for 12 h, ground for 30 min, and then placed in a muffle furnace and calcined at 500°C for 5 h to obtain TiO2@ZnFe2O4 oxide.
[0038] c) Weigh the solid obtained in step (b) and place it in a tube furnace. Pre-treat it at 300°C for 1 hour in a 5% H2 atmosphere to obtain the desired TiO2@ZnFe2O4 composite oxide catalyst with defect sites.
[0039] Example 2
[0040] Preparation of TiO2@ZnFe2O4 (1:4-200℃) composite oxide catalyst
[0041] a) Weigh 0.4 mol of zinc chloride and 0.8 mol of ferric chloride, and dissolve them in 100 mL of deionized water. Stir at room temperature for 30 min. Then, gradually add the resulting clear mixed solution and 0.1 mol of tetrabutyl titanate to 200 mL of 2 mol / L ammonia solution and continue stirring for 2 h.
[0042] b) The solid obtained in step (a) was filtered and washed with excess deionized water and ethanol until the pH of the solution dropped to 7. The solid was then dried at 120°C for 24 h, ground for 30 min, and then placed in a muffle furnace and calcined at 500°C for 4 h to obtain TiO2@ZnFe2O4 oxide.
[0043] c) Weigh the solid obtained in step (b) and place it in a tube furnace. Pre-treat it at 200°C for 1 hour in a 5% H2 atmosphere to obtain the desired TiO2@ZnFe2O4 composite oxide catalyst with defect sites.
[0044] Example 3
[0045] Preparation of TiO2@ZnFe2O4 (1:4-400℃) composite oxide catalyst
[0046] a) Weigh 0.2 mol of zinc chloride and 0.4 mol of ferric chloride, and dissolve them in 50 mL of deionized water. Stir at room temperature for 30 min. Then, gradually add the resulting clear mixed solution and 0.05 mol of tetrabutyl titanate to 200 mL of 1 mol / L ammonia solution, and continue stirring for 2 h.
[0047] b) The solid obtained in step (a) was filtered and washed with excess deionized water and ethanol until the pH of the solution dropped to 7. The solid was then dried at 120°C for 24 h, ground for 30 min, and then placed in a muffle furnace and calcined at 500°C for 6 h to obtain TiO2@ZnFe2O4 oxide.
[0048] c) Weigh the solid obtained in step (b) and place it in a tube furnace. Pre-treat it at 400°C for 1 hour in a 5% H2 atmosphere to obtain the desired TiO2@ZnFe2O4 composite oxide catalyst with defect sites.
[0049] Comparative Example 1
[0050] Preparation of TiO2@ZnFe2O4 catalyst
[0051] a) Weigh 0.3 mol of zinc chloride and 0.6 mol of ferric chloride, and dissolve them in 50 mL of deionized water. Stir at room temperature for 30 min. Then, gradually add the resulting clear mixed solution dropwise to 200 mL of 1 mol / L ammonia solution and continue stirring for 2 h.
[0052] b) The solid obtained in step (a) was filtered and washed with excess deionized water and ethanol until the pH of the solution dropped to 7. The solid was then dried at 120°C for 24 h, ground for 30 min, and then placed in a muffle furnace and calcined at 500°C for 4 h to obtain @ZnFe2O4 oxide.
[0053] c) Weigh the solid obtained in step (b) and place it in a tube furnace. Pre-treat it at 400°C for 1 hour in a 5% H2 atmosphere to obtain the ZnFe2O4 oxide catalyst with the desired defect sites.
[0054] Comparative Example 2
[0055] Preparation of TiO2 oxide catalysts
[0056] a) Weigh 0.01 mol of tetrabutyl titanate and gradually add it dropwise to 50 mL of 1 mol / L ammonia solution, and continue stirring for 2 h.
[0057] b) The solid obtained in step (a) was filtered and washed with excess deionized water and ethanol until the pH of the solution dropped to 7. The solid was then dried at 120°C for 12 h, ground for 30 min, and then placed in a muffle furnace and calcined at 500°C for 5 h to obtain TiO2 oxide.
[0058] c) Weigh the solid obtained in step (b) and place it in a tube furnace. Pre-treat it at 300°C for 1 hour in a 5% H2 atmosphere to obtain the TiO2 oxide catalyst with the desired defect sites.
[0059] Performance testing
[0060] 1. XRD test
[0061] The crystal forms of the catalysts in Examples 1-3 were tested using X-ray diffraction, and the results are as follows: Figure 1 As shown. No significant difference was observed between the characteristic peaks of the defective TiO2@ZnFe2O4 sample and the crystallinity of the TiO2@ZnFe2O4 sample. All samples showed characteristic diffraction peaks of spinel ZnFe2O4 (JCPDS card No. 22-1012). The diffraction peaks at 2θ = 18.22°, 30.7°, 35.31°, 36.69°, 42.83°, 53.9°, 56.52° and 62.22° correspond to the (111), (220), (311), (222), (400), (442), (511) and (440) crystal planes, respectively. Similarly, anatase TiO2 characteristic diffraction peaks also appeared (JCPDS21-1271), 2θ = 17.84°, 25.28°, 37.86°, 47.98°, 54.69°, 56.68°, 62.35°, 69.97°, 70.11° and 75.39°. Figure 1 b shows the XRD patterns of TiO2@ZnFe2O4 samples under different reduction temperatures. It was found that the intensity of the diffraction peaks of the samples in the figure gradually increased with the increase of reduction temperature.
[0062] 2. Photocatalytic degradation experiment
[0063] Methyl orange (MO) was selected as a representative organic pollutant for photocatalytic degradation experiments under UV-Vis irradiation. Before the degradation experiment, 50 mg of the defective heterojunction materials from Examples 1-3 and Comparative Examples 1-3 were added to the MO degradation solution (50 ml, 10 ppm). The powdered catalyst was dispersed by sonication. The mixed liquid was placed in a dark environment and magnetically stirred for 30 min until the catalyst and MO reached adsorption-desorption equilibrium. The concentration of the sample solution was recorded as C0. The mixed liquid was then placed under a xenon lamp illuminator to simulate visible light for 120 min. Samples were taken every 20 min to measure the concentration, recorded as Ct. All samples were placed in a dark environment, with 3 ml taken each time. Each sampling was performed in a dark room, taking the supernatant, with a sample volume of approximately 3 ml. The absorbance of the target substance after photocatalytic degradation was measured using a UV-Vis spectrophotometer (752N). The results are as follows: Figure 2 As shown. The reaction of Example 1 was then cycled 10 times for degradation, and the results are as follows. Figure 3 As shown
[0064] Depend on Figure 2 It can be seen that comparing the degradation rates of MO by defective TiO2@ZnFe2O4 and TiO2@ZnFe2O4 materials, it is found that complete degradation of MO requires about 70 min. Furthermore, it was found that the three samples prepared by hydrogen reduction at different temperatures (TiO2@ZnFe2O4 (1:4-200℃), TiO2@ZnFe2O4 (1:4-300℃), and TiO2@ZnFe2O4 (1:4-400℃)) showed better catalytic performance. In particular, TiO2@ZnFe2O4 (1:4-300℃) showed the best photocatalytic performance compared to other samples, and it only took 35 min to completely degrade all MO.
[0065] Even after ten cycles, the catalyst of this invention still achieved a MO degradation rate of 97.3%. These experimental results demonstrate that the defective TiO2@ZnFe2O4 (1:4-300℃) sample prepared in this work has significant potential value and practical application in improving photocatalytic performance.
[0066] Industrial availability
[0067] The defective TiO2@ZnFe2O4 catalyst provided by the invention can be industrially prepared and applied to the degradation of organic pollutants.
[0068] Although the technical solutions of the present invention have been described and enumerated in detail, it should be understood that modifications to the above embodiments or the adoption of equivalent alternatives are obvious to those skilled in the art. Such modifications or improvements made without departing from the spirit of the present invention are all within the scope of protection claimed by the present invention.
Claims
1. An in-situ preparation method for TiO2@ZnFe2O4 composite oxide catalyst, characterized in that, The composition of the TiO2@ZnFe2O4 composite oxide catalyst is represented as TiO2@ZnFe2O4(x:y), where x and y represent the molar ratio of TiO2 to ZnFe2O4, and x:y = 1:
4.
2. A method for preparing an in-situ TiO2@ZnFe2O4 composite oxide catalyst, characterized in that, It is prepared by reverse precipitation and H2 reduction.
3. The method for preparing an in-situ TiO2@ZnFe2O4 composite oxide catalyst according to claim 2, characterized in that, Includes the following steps: Step (1): Weigh 0.2-0.4 mol of zinc chloride and 0.4-0.8 mol of ferric chloride, and dissolve them in 100 mL of deionized water. Stir at room temperature for 30-60 min to obtain a clear solution for later use. Step (2): Weigh 0.05-0.1 mol of tetrabutyl titanate and disperse it in anhydrous ethanol. Stir for 10-20 min at room temperature to obtain a solution for later use. Step (3): Weigh an appropriate amount of ammonia water and prepare an ammonia water solution with a concentration of 0-2 mol / L, and set aside for later use; Step (4): Add the clear solution obtained in steps (1) and (2) dropwise to the solution prepared in step (3), stir for a certain period of time, and set aside for later use; Step (5): Take the reaction solution obtained in step (4), filter, wash, and dry it, and then calcine it in a muffle furnace to obtain TiO2@ZnFe2O4 composite oxide; Step (6): Place the mixture obtained in step (5) in a tube furnace and pre-treat it with an atmosphere to obtain the desired TiO2@ZnFe2O4 composite oxide with defects.
4. The method for preparing an in-situ TiO2@ZnFe2O4 composite oxide catalyst according to claim 3, characterized in that, In step (5), the reaction solution obtained in step (4) is filtered, washed, dried at 120°C for 12-24 hours, and then placed in a muffle furnace and calcined at 500°C for 4-8 hours to obtain TiO2@ZnFe2O4 oxide.
5. The method for preparing an in-situ TiO2@ZnFe2O4 composite oxide catalyst according to claim 3, characterized in that, In step (6), the mixture obtained in step (5) is placed in a tube furnace and pretreated at 200-400℃ for 1-2 hours in a 1-5% H2 atmosphere to obtain the desired TiO2@ZnFe2O4 composite oxide.
6. The application of the in-situ preparation of TiO2@ZnFe2O4 composite oxide catalyst according to claim 1, characterized in that, Includes the following steps: 50 mg of defective TiO2@ZnFe2O4 heterojunction material was added to a MO solution (50 ml, 10 ppm). The powdered catalyst was dispersed by sonication. The mixture was then magnetically stirred in the dark for 30 min until the catalyst and MO reached adsorption-desorption equilibrium. A sample solution was taken and its concentration recorded as C0. The mixture was then irradiated under a xenon lamp simulating visible light for 120 min, with samples taken every 20 min to determine the concentration, which was recorded as C0. t All samples were placed in a dark environment, with 3 ml taken each time. Each sampling was performed in a dark room to collect the supernatant, with a sample volume of approximately 3 ml. The absorbance of the target substance after photocatalytic degradation was measured using a UV-Vis spectrophotometer (752N).
7. The application of the in-situ preparation of TiO2@ZnFe2O4 composite oxide catalyst according to claim 6, characterized in that, It is not only used in the field of photocatalytic degradation to remove organic pollutants, which can completely degrade all organic pollutants in a short time, but also has broad prospects in the field of photocatalytic hydrogen production.