Magnetic photocatalytic VOC (volatile organic compound) removal material as well as preparation method and application thereof
By leveraging the photothermal synergistic effect of magnetic photocatalytic materials, combined with TiO2/CoFe2O4 and CQDs, the problems of high thermal catalysis energy consumption and low photocatalytic activity are solved, achieving efficient and economical VOCs degradation, which is suitable for air pollutant treatment.
Patent Information
- Application Number
- CN202511470264.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-15
- Publication Date
- 2026-01-16
AI Technical Summary
In existing technologies, thermocatalysis processes consume a lot of energy, and photocatalysts have short catalytic lifetimes and low activity, making it difficult to effectively treat volatile organic compounds (VOCs).
A magnetic photocatalytic VOC removal material was developed. Through photothermal synergy, a coupled photothermal catalytic system was formed by combining titanium dioxide/cobalt ferrite (TiO2/CoFe2O4) and carbon quantum dots (CQDs). The catalytic activity was improved by utilizing the synergistic effect of solar energy and thermochemistry, and the material can be recycled.
It significantly improves the activity and stability of the catalyst, broadens the scope of solar energy utilization, reduces energy consumption, achieves efficient VOCs degradation, and has the characteristics of being economical and environmentally friendly.
Smart Images
Figure CN121338751A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the field of photocatalytic material preparation and air pollutant treatment, and particularly relates to a magnetic photocatalytic VOC removal material and a preparation method and application thereof. BACKGROUND
[0002] Volatile organic compounds (VOCs) are one of the main causes of urban haze and photochemical smog and other atmospheric environmental problems, mainly from coal chemical industry, petroleum chemical industry, fuel paint manufacturing, solvent manufacturing and using processes. The emission of VOCs restricts the sustainable development of the environment, and effective and comprehensive implementation of VOCs prevention and control is a difficult task. In the past few decades, VOCs control has mainly been based on end-of-pipe treatment, including means such as adsorption, membrane separation, plasma, biodegradation, catalytic degradation, and removal of VOCs by various environmental functional materials. Catalytic oxidation is one of the most effective ways to treat VOCs. There have been many studies on photocatalysts and thermal catalysts used for treating VOCs, but the huge energy consumption in the thermal catalytic process and the difficulties in solving the short catalytic life and low activity in the photocatalytic process are difficult to solve. SUMMARY
[0003] In view of the above problems, the application develops a magnetic photocatalytic VOC removal material that can realize light-heat cooperation, adjusts the reaction pathway through the synergistic effect of photochemical and thermal chemical processes, forms a coupled light-heat catalytic system, realizes the synergistic effect of solar energy and thermal chemistry, can significantly improve the catalytic activity, solves the problems of high energy consumption of traditional thermal catalytic oxidation technology and low efficiency of photocatalytic technology, and the catalyst can be recycled and used, which has great development prospects.
[0004] In order to achieve the above-mentioned purpose of the application, the following technical scheme is adopted:
[0005] In a first aspect, the application provides a preparation method of a magnetic photocatalytic material for degrading VOCs through light-heat cooperation, comprising the following steps:
[0006] (1) providing cobalt ferrite (CoFe2O4);
[0007] (2) preparation of titanium dioxide / cobalt ferrite: placing the cobalt ferrite into a solvent, ultrasonic dispersion, then adding diethylenetriamine ((NH2CH2CH2)2NH) and titanium isopropoxide, fully stirring, separating to obtain a solid, washing, drying, calcining, to obtain titanium dioxide / cobalt ferrite (TiO2 / CoFe2O4);
[0008] (3) Preparation of carbon quantum dots (CQDs): Citric acid and ethylenediamine (EDA) were dissolved in deionized water and stirred uniformly, and the solution was transferred to a sealed stainless steel autoclave for hydrothermal reaction. After the reaction, the cooled mixture was purified by dialysis, and finally a yellow-brown carbon quantum dot solution was obtained.
[0009] (4) Preparation of carbon quantum dots-titanium dioxide / cobalt ferrite (CQDs-TiO2 / CoFe2O4): Titanium dioxide / cobalt ferrite was placed in the carbon quantum dot solution and stirred uniformly at room temperature, and then the mixture was transferred to a stainless steel autoclave for hydrothermal reaction. After the reaction, the solid was obtained by filtration, and after washing several times with ethanol solution, drying and calcining, carbon quantum dots-titanium dioxide / cobalt ferrite was obtained.
[0010] The following will be described in detail:
[0011] Step (1) Cobalt ferrite can be obtained commercially or prepared by oneself.
[0012] As a preferred, the preparation of step (1) cobalt ferrite includes: Fe(NO3)2·9H2O and Co(NO3)3·6H2O are dissolved in 50 ml of distilled water respectively, then citric acid solution is added to disperse the solute; After the mixed solution is mixed uniformly, NaOH is added to adjust the pH of the solution to alkaline and form a brown precipitate; The brown precipitate is collected and washed several times with ethanol solution, and after drying and calcining, CoFe2O4 is obtained.
[0013] As a preferred, the volume ratio of distilled water and citric acid solution in step (1) is 1-2:1; the concentration of citric acid solution is 1-5 mM; more preferably, the concentration of citric acid solution is 1 mM.
[0014] As a preferred, the molar ratio of Fe(NO3)2·9H2O and Co(NO3)3·6H2O in step (1) is 4-5:1.
[0015] As a preferred, the pH of the solution adjusted by NaOH in step (1) is 7-14; more preferably, the pH of the solution adjusted by NaOH is 8-9.
[0016] As a preferred, the calcination temperature in step (1) is between 450-600℃, and the calcination time is 2-3h.
[0017] As a preferred, the solvent in step (2) is selected from one or more of deionized water, distilled water, and ethanol solution; more preferably, the solution is selected from ethanol solution (concentration not required).
[0018] Preferably, the molar ratio of cobalt ferrite and titanium isopropoxide in step (2) is 3-5:1, and the amount of diethylene triamine added is 300-500 μL.
[0019] Preferably, the calcination temperature in step (2) is 240-400 ℃, and the calcination time is 2-3 h.
[0020] Preferably, the amount of citric acid used in step (3) is 5-8 g, and more preferably, the amount is 6 g, and the amount of ethylenediamine used is 2-3 ml, and more preferably, the amount is 2 ml.
[0021] Preferably, the hydrothermal reaction temperature in step (3) is 180-200 ℃, the reaction time is 4-5 h, and more preferably, the reaction time is 5 h, and the dialysis purification time is 24 h.
[0022] Preferably, the amount of titanium dioxide / cobalt ferrite used in step (4) is 2 g, and the amount of carbon quantum dot solution used is 10-20 ml.
[0023] Preferably, the hydrothermal reaction temperature in step (4) is 140-180 ℃, and the reaction time is 24 h.
[0024] The integration of TiO2 and CoFe2O4 induces the formation of Ti 3+ sites, significantly reduces the optical band gap of TiO2, and improves the utilization efficiency of the catalyst for solar energy; at the same time, the local high temperature generated by the absorption of flue gas waste heat by the magnetic component (CoFe2O4) realizes the synergistic degradation of VOCs by light and heat; in addition, the modification of CQDs modifies the Ti 3+ sites to form Ti-C bonds, which improves the separation of charge carriers and effectively promotes electron transfer, further enhancing the activity of the catalyst. The catalyst can effectively couple solar energy-thermal energy to catalytically degrade VOCs, and can be separated and recycled after the reaction, with the advantages of superior catalytic performance, environmental friendliness, and low cost.
[0025] In a second aspect, the present application provides a magnetic photocatalytic VOC removal material prepared by the above preparation method.
[0026] In a third aspect, the present application provides an application of a magnetic photocatalytic VOC removal material in the synergistic degradation of VOCs by light and heat.
[0027] The catalyst described in the present application has excellent stability and catalytic reaction performance, and the beneficial effects are as follows:
[0028] (1) The magnetic component of CoFe2O4 can absorb flue gas waste heat to generate local high temperature, which synergistically enhances the degradation efficiency of VOCs with the photocatalytic effect of TiO2, and widens the range of solar energy utilization.
[0029] (2) CQDs improve the separation efficiency of electron-hole pairs by forming Ti-C bonds, while exposing more active sites to accelerate the reaction kinetics.
[0030] (3) TiO2 and CoFe2O4 form a heterostructure, and the band matching at the interface can effectively inhibit the recombination of photo-generated electron-hole pairs, and improve the photocatalytic activity. In the process of recombination, the introduction of CoFe2O4 induces the generation of Ti 3+ defects on the surface of TiO2, narrows its optical band gap, enhances the absorption capacity of visible light, and broadens the light response range.
[0031] (4) The present application realizes efficient and recyclable VOCs degradation through the synergistic design of magnetic carriers and photocatalytic components, and is suitable for air pollutant treatment field, and has significant economic and environmental benefits. BRIEF DESCRIPTION OF DRAWINGS
[0032] Figure 1 The VOCs degradation efficiency of the CQDs-TiO2 / CoFe2O4 catalyst provided by the embodiments of the present application. DETAILED DESCRIPTION
[0033] The present application will be further described below in conjunction with examples, and it should be noted that the following examples are provided only for illustrative purposes and do not constitute a limitation on the scope of protection required by the present application.
[0034] Unless otherwise specified, the raw materials, reagents, methods, etc. used in the examples are conventional raw materials, reagents, methods in the art.
[0035] Example 1
[0036] (1) Preparation of CoFe2O4: 40 g (0.1 mol) Fe(NO3)2·9H2O and 7.3 g (0.025 mol) Co(NO3)3·6H2O were dissolved in 50 ml of distilled water, respectively, and then mixed with 50 ml of 1 mM citric acid solution. The mixed solution was treated by ultrasonic for 2 h, then stirred for 3 h, and then NaOH was added to adjust the pH of the solution to 9, forming a brown precipitate. The brown precipitate was collected and washed several times with ethanol solution, and dried at 70℃ for 12 h. The obtained solid material was calcined at 550℃ for 2 h to obtain CoFe2O4.
[0037] (2) Preparation of TiO2 / CoFe2O4: 2.3 g (0.01 mol) of CoFe2O4 was taken in 40 ml of ethanol solution and dispersed in the solvent by ultrasonic technique, then 400 μl of (NH2CH2CH2)2NH and 0.7 g (0.0025 mol) of titanium isopropoxide were added and stirred well for 4 h, the solid obtained was washed several times with ethanol solution and dried at 70 °C for 12 h, then calcined at 400 °C for 2 h to obtain TiO2 / CoFe2O4.
[0038] (3) Preparation of CQDS: 6 g (0.03 mol) of citric acid and 2 ml of ethylenediamine were dissolved in 60 ml of deionized water and stirred well for 4 h, the solution obtained was transferred to a sealed stainless steel autoclave and subjected to hydrothermal reaction at a temperature of 180 °C for a time period of 5 h, after completion of the reaction the cooled mixture was purified by dialysis for 24 h to obtain a yellowish brown solution of CQDs.
[0039] (4) Preparation of CQDs-TiO2 / CoFe2O4: 2 g (0.008 mol) of TiO2 / CoFe2O4 was added to 10 ml of CQDs solution and stirred at room temperature for 4 h, the solution obtained was transferred to a sealed stainless steel autoclave and subjected to hydrothermal reaction at a temperature of 180 °C for a time period of 24 h, after completion of the reaction the solid obtained was washed several times with ethanol solution and dried, then placed in a tube furnace and calcined at 300 °C for 2 h to obtain CQDs-TiO2 / CoFe2O4.
[0040] Example 2
[0041] (1) Preparation of CoFe2O4: 40 g (0.1 mol) of Fe(NO3)2.9H2O and 6 g (0.02 mol) of Co(NO3)3.6H2O were separately dissolved in 50 ml of distilled water and mixed, then 50 ml of 1 mM concentration of citric acid solution was added. The mixed solution was subjected to ultrasonic treatment for 2 h and stirred for 3 h, then NaOH was added to adjust the pH of the solution to 9 to form a brown precipitate. The brown precipitate was collected and washed several times with ethanol solution and dried at 70 °C for 12 h, the solid obtained was calcined at 450 °C for 2 h to obtain CoFe2O4.
[0042] (2) Preparation of TiO2 / CoFe2O4: 2.3 g (0.01 mol) of CoFe2O4 was taken in 40 ml of ethanol solution and dispersed in the solvent by ultrasonic technique, then 400 μl of (NH2CH2CH2)2NH and 0.7 g (0.0025 mol) of titanium isopropoxide were added and stirred well for 4 h, the solid obtained was washed several times with ethanol solution and dried at 70 °C for 12 h, then calcined at 240 °C for 2 h to obtain TiO2 / CoFe2O4.
[0043] (3) Preparation of CQDS: 5 g (0.025 mol) of citric acid was dissolved in 2 ml of ethylenediamine in 60 ml of deionized water and stirred well for 4 h, the solution obtained was transferred to a sealed stainless steel autoclave and subjected to hydrothermal reaction at a temperature of 180 °C for a time period of 4 h, after completion of the reaction the cooled mixture was purified by dialysis for 24 h to obtain a yellowish brown solution of CQDs.
[0044] (4) Preparation of CQDs-TiO2 / CoFe2O4: 2 g (0.008 mol) of TiO2 / CoFe2O4 was added to 10 ml of CQDs solution and stirred at room temperature for 4 h, the solution obtained was transferred to a sealed stainless steel autoclave and subjected to hydrothermal reaction at a temperature of 180 °C for a time period of 24 h, after completion of the reaction the solid obtained was washed several times with ethanol solution and dried, then placed in a tube furnace and calcined at 300 °C for 2 h to obtain CQDs-TiO2 / CoFe2O4.
[0045] Example 3
[0046] (1) Preparation of CoFe2O4: 40 g (0.1 mol) of Fe(N03)2.9H2O and 7.3 g (0.025 mol) of Co(N03)3.6H2O were separately dissolved in 50 ml of distilled water and mixed, then 50 ml of 1 mM concentration of citric acid solution was added. The mixed solution was subjected to ultrasonic treatment for 2 h and stirred for 3 h, then NaOH was added to adjust the pH of the solution to 9 to form a brown precipitate. The brown precipitate was collected and washed several times with ethanol solution and dried at 70 °C for 12 h, the solid obtained was calcined at 600 °C for 3 h to obtain CoFe2O4.
[0047] (2) Preparation of TiO2 / CoFe2O4: 2.3 g (0.01 mol) CoFe2O4 was placed in 40 ml of ethanol solution and dispersed in the solvent by ultrasonic technology. Then, 500 μl (NH2CH2CH2)2NH and 0.56 g (0.002 mol) titanium isopropoxide were added and stirred for 4 h. After obtaining the solid, it was washed several times with ethanol solution, dried at 70℃ for 12 h, and then calcined at 400℃ for 3 h to obtain TiO2 / CoFe2O4.
[0048] (3) Preparation of CQDS: 8 g (0.04 mol) of citric acid and 3 ml of ethylenediamine were dissolved in 60 ml of deionized water and stirred thoroughly for 4 h. The resulting solution was transferred to a sealed stainless steel autoclave and subjected to a hydrothermal reaction at 180°C for 5 h. After the reaction was completed, the cooled mixture was purified by dialysis for 24 h to obtain a yellow-brown CQDS solution.
[0049] (4) Preparation of CQDs–TiO2 / CoFe2O4: 2 g (0.008 mol) TiO2 / CoFe2O4 was added to 20 ml of CQDs solution and stirred at room temperature for 4 h. The resulting solution was transferred to a sealed stainless steel autoclave and subjected to a hydrothermal reaction at 180°C for 24 h. After the reaction was completed, the solid obtained by filtration was washed several times with ethanol solution and dried. Then it was placed in a tube furnace and calcined at 250°C for 2 h to obtain CQDs–TiO2 / CoFe2O4.
[0050] Comparative Example 1
[0051] (1) Preparation of CoFe2O4: 40 g (0.1 mol) Fe(NO3)2·9H2O and 7.3 g (0.025 mol) Co(NO3)3·6H2O were dissolved in 50 ml of distilled water and then mixed. 50 ml of 1 mM citric acid solution was then added. The mixed solution was sonicated for 2 h and stirred continuously for 3 h. NaOH was then added to adjust the pH of the solution to 9, forming a brown precipitate. The brown precipitate was collected, washed several times with ethanol solution, and dried at 70 °C for 12 h. The resulting solid was calcined at 550 °C for 2 h to obtain CoFe2O4.
[0052] (2) Preparation of CQDs: 6 g (0.03 mol) of citric acid and 2 ml of ethylenediamine were dissolved in 60 ml of deionized water and stirred thoroughly for 4 h. The resulting solution was transferred to a sealed stainless steel autoclave and subjected to a hydrothermal reaction at 180°C for 5 h. After the reaction was completed, the cooled mixture was purified by dialysis for 24 h to obtain a yellow-brown CQDs solution.
[0053] (3) Preparation of CQDs–CoFe2O4: 1.9 g (0.008 mol) CoFe2O4 was added to 10 ml of CQDs solution and stirred at room temperature for 4 h. The resulting solution was transferred to a sealed stainless steel autoclave and subjected to a hydrothermal reaction at 180°C for 24 h. After the reaction was completed, the solid obtained by filtration was washed several times with ethanol solution and dried. Then it was placed in a tube furnace and calcined at 250°C for 2 h to obtain CQDs–CoFe2O4.
[0054] Comparative Example 2
[0055] (1) Preparation of TiO2: 400 μl of (NH2CH2CH2)2NH and 0.7 g (0.0025 mol) of titanium isopropoxide were stirred for 4 h to obtain a solid. The solid was washed several times with ethanol solution, dried at 70℃ for 12 h, and then calcined at 300℃ for 2 h to obtain TiO2.
[0056] (2) Preparation of CQDs: 6 g (0.03 mol) of citric acid and 2 ml of ethylenediamine were dissolved in 60 ml of deionized water and stirred thoroughly for 4 h. The resulting solution was transferred to a sealed stainless steel autoclave and subjected to a hydrothermal reaction at 180°C for 5 h. After the reaction was completed, the cooled mixture was purified by dialysis for 24 h to obtain a yellow-brown CQDs solution.
[0057] (3) Preparation of CQDs–TiO2: 0.64 g (0.008 mol) TiO2 was added to 10 ml of CQDs solution and stirred at room temperature for 4 h. The resulting solution was transferred to a sealed stainless steel autoclave and subjected to a hydrothermal reaction at 180°C for 24 h. After the reaction was completed, the solid obtained by filtration was washed several times with ethanol solution and dried. Then it was placed in a tube furnace and calcined at 300°C for 2 h to obtain CQDs–TiO2.
[0058] Comparative Example 3
[0059] (1) Preparation of CoFe2O4: 40 g (0.1 mol) Fe(NO3)2·9H2O and 7.3 g (0.025 mol) Co(NO3)3·6H2O were dissolved in 50 ml of distilled water and then mixed. 50 ml of 1 mM citric acid solution was then added. The mixed solution was sonicated for 2 h and stirred continuously for 3 h. NaOH was then added to adjust the pH of the solution to 9, forming a brown precipitate. The brown precipitate was collected, washed several times with ethanol solution, and dried at 70 °C for 12 h. The resulting solid was calcined at 550 °C for 2 h to obtain CoFe2O4.
[0060] (2) Preparation of TiO2 / CoFe2O4: 2.3 g (0.01 mol) CoFe2O4 was placed in 40 ml of ethanol solution and dispersed in the solvent by ultrasonic technology. Then, 400 μl (NH2CH2CH2)2NH and 0.9 g (0.0025 mol) titanium isopropoxide were added and stirred for 4 h. After obtaining the solid, it was washed several times with ethanol solution, dried at 70℃ for 12 h, and then calcined at 400℃ for 2 h to obtain TiO2 / CoFe2O4.
[0061] Comparative Example 4
[0062] (1) Preparation of CoFe2O4: 40 g (0.1 mol) Fe(NO3)2·9H2O and 7.3 g (0.025 mol) Co(NO3)3·6H2O were dissolved in 50 ml of distilled water and then mixed. 50 ml of 1 mM citric acid solution was then added. The mixed solution was sonicated for 2 h and stirred continuously for 3 h. NaOH was then added to adjust the pH of the solution to 9, forming a brown precipitate. The brown precipitate was collected, washed several times with ethanol solution, and dried at 70 °C for 12 h. The resulting solid was calcined at 550 °C for 2 h to obtain CoFe2O4.
[0063] (2) Preparation of TiO2 / CoFe2O4 physical mixture: 2.3 g (0.01 mol) CoFe2O4 and 0.02 g (0.0025 mol) titanium dioxide were mixed and ground several times in a quartz mortar and sieved through a 60 mesh. After obtaining the solid, it was washed several times with ethanol solution, dried at 70℃ for 12 h, and then calcined at 300℃ for 2 h to obtain TiO2 / CoFe2O4 physical mixture.
[0064] (3) Preparation of CQDS: 6 g (0.03 mol) of citric acid and 2 ml of ethylenediamine were dissolved in 60 ml of deionized water and stirred thoroughly for 4 h. The resulting solution was transferred to a sealed stainless steel autoclave and subjected to a hydrothermal reaction at 180°C for 5 h. After the reaction was completed, the cooled mixture was purified by dialysis for 24 h to obtain a yellow-brown CQDS solution.
[0065] (4) Preparation of CQDs–TiO2 / CoFe2O4 physical mixture: 2 g (0.008 mol) of TiO2 / CoFe2O4 physical mixture was added to 10 ml of CQDs solution and stirred at room temperature for 4 h. The resulting solution was transferred to a sealed stainless steel autoclave and subjected to a hydrothermal reaction at 180°C for 24 h. After the reaction was completed, the solid obtained by filtration was washed several times with ethanol solution and dried. Then it was placed in a tube furnace and calcined at 300°C for 2 h to obtain CQDs–TiO2 / CoFe2O4 physical mixture.
[0066] The catalysts from Examples 1-3 and Comparative Examples 1-4 were subjected to VOCs degradation tests at 200-250°C. The test conditions were: NO 500 ppm, NH3 / NO molar ratio 1.0, O2 10%, and space velocity 21000 h⁻¹. -1 The test results are shown in the figure below.
[0067] As shown in the figure below, under the test conditions of 200~250℃, the VOCs degradation efficiency of the catalysts provided in the examples can reach more than 90%. With the increase of reaction time, the VOCs degradation efficiency still remains above 80%, which shows strong stability and VOCs degradation performance.
[0068] It should be understood that the above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They are not an exhaustive list of specific implementation methods and cannot be used 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 covered within the scope of the claims of the present invention.
Claims
1. A method of preparing a magnetic photocatalytic VOC removal material, characterized by, The method comprises the following steps: (1) providing cobalt ferrite; (2) preparation of titanium dioxide / cobalt ferrite: placing cobalt ferrite into a solvent, ultrasonic dispersion, then adding diethylene triamine and titanium isopropoxide, stirring, separating to obtain a solid, washing, drying, and calcining to obtain titanium dioxide / cobalt ferrite; (3) preparation of carbon quantum dots: dissolving citric acid and ethylenediamine in deionized water, stirring, transferring the solution into a sealed stainless steel autoclave for hydrothermal reaction, purifying the cooled mixture by dialysis, and finally obtaining a yellow-brown carbon quantum dot solution; (4) preparation of carbon quantum dot-titanium dioxide / cobalt ferrite: placing titanium dioxide / cobalt ferrite into the carbon quantum dot solution and stirring uniformly at room temperature, then transferring the mixture into a stainless steel autoclave for hydrothermal reaction, filtering to obtain a solid, washing with an ethanol solution for several times, drying, and calcining to obtain carbon quantum dot-titanium dioxide / cobalt ferrite.
2. The production method according to claim 1, characterized by, The preparation of cobalt ferrite in step (1) comprises: dissolving Fe(NO3)2·9H2O and Co(NO3)3·6H2O in 50 ml of distilled water respectively, then mixing, adding a citric acid solution to disperse the solute, uniformly mixing the mixed solution, adding NaOH to adjust the pH of the solution to alkaline, and forming a brown precipitate; collecting the brown precipitate, washing with an ethanol solution for several times, and drying and calcining to obtain CoFe2O4; The volume ratio of distilled water to citric acid solution is 1-2:1; the concentration of the citric acid solution is 1-5 mM; The molar ratio of Fe(NO3)2·9H2O to Co(NO3)3·6H2O is 4-5:1; The pH of the solution adjusted by NaOH is in the range of 8-9, the calcination temperature is between 450-600℃, and the calcination time is 2-3 h.
3. The production method according to claim 1, characterized by, The solvent in step (2) is selected from one or more of deionized water, distilled water, and an ethanol solution; In step (2), the molar ratio of cobalt ferrite to titanium isopropoxide is 3-5:1, and the amount of diethylene triamine added is 300-500 μL.
4. The method of claim 1, wherein, The calcination temperature in step (2) is 240-400℃, and the calcination time is 2-3 h.
5. The preparation method according to claim 1, characterized in that, In step (3), the amount of citric acid is 5-8 g, and the amount of ethylenediamine is 2-3 ml.
6. The method of claim 1, wherein, In step (3), the hydrothermal reaction temperature is 180-200℃, the reaction time is 4-5 h, and the dialysis purification time is 24 h.
7. The preparation method according to claim 1, characterized in that, In step (4), the amount of titanium dioxide / cobalt ferrite is 2 g, and the amount of carbon quantum dot solution is 10-20 ml.
8. The method of claim 1, wherein, In step (4), the hydrothermal reaction temperature is 140-180℃, and the hydrothermal time is 24 h.
9. A magnetic photocatalytic VOC removal material, characterized in that, Prepared by the preparation method of any one of claims 1-8.
10. Use of the magnetic photocatalytic VOC removal material of claim 9 in the photothermal synergistic degradation of VOCs.