Ligand defect type MOF photocatalyst, preparation method thereof and application of ligand defect type MOF photocatalyst in biodiesel preparation

Abstract

The invention provides a ligand defect type MOF photocatalyst, a preparation method thereof and application of the ligand defect type MOF photocatalyst in biodiesel preparation, and belongs to the technical field of biomass catalytic conversion. The preparation method of the photocatalyst comprises the following steps: carrying out solvothermal reaction on a zirconium precursor, 2-aminoterephthalic acid and terephthalic acid in a solvent to obtain a catalyst precursor; the catalyst precursor is subjected to calcination treatment and activation treatment in sequence, and the ligand defect type MOF photocatalyst is obtained. The MOF material which is simple in synthesis step and easy to accurately regulate and control is used as a matrix, the photocatalyst with ligand defects is designed and developed through a pyrolysis method, and the catalyst shows a remarkable mesoporous structure, good crystallinity and enhanced visible light response capability. The ligand defect type MOF photocatalyst is used for catalyzing esterification or transesterification of grease and methanol, so that high biodiesel yield is obtained, and the ligand defect type MOF photocatalyst has huge potential of improving economic and environmental benefits.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biomass catalytic conversion, in particular to a ligand-defective MOF photocatalyst, a preparation method thereof and application thereof in biodiesel preparation. BACKGROUND

[0002] In recent years, the global energy crisis has become increasingly prominent. The contradiction between the limited reserves of fossil fuels (such as oil and coal) and the growing energy demand has become acute, leading to intensified fluctuations in energy prices and frequent environmental pollution. Under this background, the development of renewable clean energy has become a global consensus. Biodiesel, as a clean fuel prepared from plant and animal oils, waste oils and other raw materials, has the advantages of being renewable, low in sulfur emissions and miscible with traditional diesel, and is considered an important way to alleviate the energy crisis and reduce carbon emissions. Its carbon emissions during combustion are significantly lower than those of traditional fossil fuels, and carbon cycling can be achieved through plant photosynthesis, which meets the global carbon neutralization goal. In addition, biodiesel can be directly applied to existing diesel engines without the need for large-scale infrastructure modifications, and has broad industrialization prospects.

[0003] In the photocatalytic preparation of biodiesel, metal-organic framework (MOF) materials have significant potential, but the MOF materials prepared by traditional synthesis methods face problems such as active site shielding, insufficient visible light response and mass transfer resistance caused by microporous structure. SUMMARY

[0004] Therefore, the present application aims to provide a ligand-defective MOF photocatalyst, a preparation method thereof and application thereof in biodiesel preparation. By introducing ligand defects through defect engineering, the present application can expose active sites and enhance catalytic performance. By adjusting the ratio of mixed ligands and pyrolysis treatment, the present application constructs a ligand-defective MOF photocatalyst with mesoporous structure and high active sites, significantly improving its efficiency in catalytic preparation of biodiesel.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0006] One of the technical solutions of the present application is a preparation method of a ligand-defective MOF photocatalyst, comprising the following steps:

[0007] Solvent-thermal reaction of zirconium precursor, 2-amino terephthalic acid and terephthalic acid in a solvent to obtain a catalyst precursor;

[0008] Calcination treatment and activation treatment of the catalyst precursor in sequence to obtain the ligand-defective MOF photocatalyst.

[0009] The second technical solution of the present application is a ligand-defective MOF photocatalyst prepared by the above-mentioned preparation method.

[0010] The third technical solution of the present application is an application of the above-mentioned ligand-deficient MOF photocatalyst in the preparation of biodiesel from oil by photocatalysis.

[0011] The present application discloses the following technical effects:

[0012] The present application uses MOF material with simple synthesis steps and easy to accurately control as a matrix, and designs and develops a photocatalyst with ligand defects by a pyrolysis method. The catalyst optimizes the distribution of photocatalytic active sites through the ligand defect regulation strategy, and constructs a catalytic environment suitable for the efficient synthesis of biodiesel. The catalyst exhibits a significant mesoporous structure, good crystallinity and enhanced visible light response ability.

[0013] The prepared catalyst is used for biodiesel production, which has the characteristics of low cost, low energy consumption, simple operation and easy to control, and excellent light response performance. Using the prepared ligand-deficient MOF photocatalyst, esterification or transesterification reaction of oil and methanol is carried out, and a high biodiesel yield is obtained, which has great potential to improve economic and environmental benefits.

[0014] The biodiesel production catalytic system constructed by the present application has good substrate universality and satisfactory catalytic performance for different oils.

[0015] The ligand-deficient MOF photocatalyst provided by the present application can significantly improve the conversion efficiency of various oils and the selectivity of biodiesel under mild reaction conditions, effectively reduce the reaction energy consumption and production cost, and provide a new technical path with both catalytic performance and economic efficiency for green large-scale production of biodiesel. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0017] Figure 1 X-ray diffraction spectrum of different samples in the present application;

[0018] Figure 2 Fourier infrared spectrum of different samples in the present application;

[0019] Figure 3 Nitrogen adsorption-desorption and pore size distribution spectrum of different samples in the present application;

[0020] Figure 4SEM images of different catalysts prepared in the present application; wherein a is SEM image of UiO-66, b is SEM image of H-UiO-66-N, c is TEM image of H-UiO-66-N, d and e are energy dispersive X-ray spectroscopy (EDS) images of H-UiO-66-N;

[0021] Figure 5 UV-Vis diffuse reflectance spectra of different samples in the present application;

[0022] Figure 6 Response surface optimization plots of H-UiO-66-N-0.3 for catalytic reaction in the present application, and biodiesel yield radar plots of the catalyst for different substrates; wherein a is the interaction effect between reaction time and catalyst dosage; b is the interaction effect between reaction time and molar ratio of alcohol to oil; c is the interaction effect between catalyst dosage and molar ratio of alcohol to oil; d is the biodiesel yield radar plot of the catalyst for different oils; e is the reusability of the catalyst. DETAILED DESCRIPTION

[0023] The various illustrative embodiments of the present application will now be described in detail in connection with the accompanying drawings. This description is made for the purpose of demonstrating various aspects of the present application and should not be taken as limiting the present application. It is to be understood that the detailed description is only one example of the disclosure and is not intended to limit the present application in any way.

[0024] It is to be understood that the terminology used in the present application is for the purpose of describing particular embodiments only and is not intended to limit the present application. In addition, for numerical ranges recited in the present application, it is contemplated that each intervening value, to the upper and lower limits of the ranges is also specifically disclosed. Each smaller range that falls within the broader ranges is also specifically disclosed. The upper and lower limits of these smaller ranges can independently be included or excluded in the range. Accordingly, the present application includes all such ranges and sub-ranges.

[0025] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although preferred methods and materials are described, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials in connection with which the documents are cited. In case of conflict between the present specification and any document incorporated by reference, the present specification will control.

[0026] Various modifications and changes can be made to the specific embodiments of the present application described herein without departing from the scope or spirit of the application. Other embodiments of the application will be apparent to those of ordinary skill in the art from the description and examples presented herein. The description and examples are illustrative of the application and are not intended to limit the scope of the application in any way.

[0027] As used herein, "comprise", "comprising", "having", "including", "contain", "containing", "include" and the like are open-ended terms that are intended to mean including, but not limited to.

[0028] Metal-organic framework (MOF) materials are crystalline porous materials formed by self-assembly of metal ions or clusters and organic ligands through coordination bonds, with ultra-high specific surface area, precisely controllable pore structure and easy functional modification, showing unique advantages in catalysis, gas storage and separation, sensing and other fields. However, traditional MOFs have problems such as active site shielding, narrow light response range and serious carrier recombination, which limit their application potential in the field of photocatalysis. To solve the above problems, the present application introduces a thermally unstable ligand 2-amino terephthalic acid and a traditional ligand (terephthalic acid) to form a mixed framework with tunable ligand composition, which has both amino active sites and stable crystal structure, and widens the visible light absorption range. On this basis, the H-UiO-66-N photocatalyst obtained by pyrolysis treatment, after selective removal of thermally unstable ligands, forms a mesoporous structure and ligand vacancy defect, exposing a large number of unsaturated Zr(IV) active centers, significantly improving the efficiency of photogenerated carrier separation and visible light response ability, and the number of mesopores is adjustable, the catalytic activity is high and the stability is excellent, showing significant advantages in the field of photocatalytic preparation of biodiesel. The H-UiO-66-N photocatalyst constructed by ligand defect engineering in the present application combines the structure tunability of MOF materials and the high efficiency of defect catalysis, and can be used as a low-cost, high-activity green heterogeneous catalyst to significantly improve the efficiency of photocatalytic preparation of biodiesel, and has broad application prospects in the field of renewable energy.

[0029] Specifically, the present application provides a preparation method of a ligand defect type MOF photocatalyst, comprising the following steps:

[0030] solvent thermal reaction of the zirconium precursor, 2-amino terephthalic acid and terephthalic acid in a solvent to obtain a catalyst precursor;

[0031] calcination treatment and activation treatment of the catalyst precursor to obtain the ligand defect type MOF photocatalyst.

[0032] In a preferred embodiment of the present application, the zirconium precursor is ZrOCl2·8H2O; the molar ratio of the zirconium precursor, 2-amino terephthalic acid and terephthalic acid is 1:(0.1-0.4):(0.3-0.8); and the solvent is a mixed solution of acetic acid and DMF in a volume ratio of 1:(0.5-2.0). In the present application, the proportion of 2-amino terephthalic acid to the total mass of 2-amino terephthalic acid and terephthalic acid is 0.1-0.6.

[0033] In the preferred embodiment of the present application, the mass-volume ratio of the zirconium precursor to acetic acid is 300-600 mg:10 mL.

[0034] In the preferred embodiment of the present application, the temperature of the solvothermal reaction is 100-150℃, and the time is 12-36 h.

[0035] Specifically, the temperature of the solvothermal reaction is 100℃, 110℃, 120℃, 130℃, 140℃ or 150℃; and the time of the solvothermal reaction is 12 h, 14 h, 16 h, 18 h, 20 h, 22 h, 24 h, 26 h, 28 h, 30 h, 32 h, 34 h or 36 h.

[0036] In the preferred embodiment of the present application, after the solvothermal reaction, the obtained reaction solution is centrifuged, the solid product is collected, and the solid product is dried; the speed of centrifugation is 8000-10000 rpm; and the temperature of drying is 60-80℃.

[0037] In the preferred embodiment of the present application, the temperature of the calcination treatment is 300-400℃, and the time is 1-5 h.

[0038] Specifically, the temperature of the calcination treatment is 300℃, 310℃, 320℃, 330℃, 340℃, 350℃, 360℃, 370℃, 380℃, 390℃ or 400℃; and the time of the calcination treatment is 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h or 5 h.

[0039] In the preferred embodiment of the present application, the temperature of the activation treatment is 60-120℃, and the time is 12-24 h.

[0040] Specifically, the temperature of the activation treatment is 60℃, 70℃, 80℃, 90℃, 100℃, 110℃ or 120℃; and the time of the activation treatment is 12 h, 13 h, 14 h, 15 h, 16 h, 17 h, 18 h, 19 h, 20 h, 21 h, 22 h, 23 h or 24 h.

[0041] The second aspect of the present application provides a ligand-deficient MOF photocatalyst prepared by the above preparation method. The ligand-deficient MOF photocatalyst is marked as H-UiO-66-N-X, wherein H indicates that the catalyst is calcined, N indicates that the catalyst contains 2-amino terephthalic acid, and X indicates the mass ratio of 2-amino terephthalic acid to the total ligand.

[0042] The third aspect of the present application provides a use of the above ligand-deficient MOF photocatalyst in the preparation of biodiesel from oil by photocatalysis.

[0043] In the preferred embodiment of the present application, the esterification reaction or transesterification reaction is carried out at room temperature and under light irradiation conditions to prepare biodiesel using oil and fat, methanol and the ligand-deficient MOF photocatalyst described above.

[0044] In the preferred embodiment of the present application, the amount of the ligand-deficient MOF photocatalyst is 1-6% of the mass of the oil and fat; the molar ratio of methanol to oil and fat is (5-20):1; the esterification reaction or transesterification reaction is carried out for 1-6h; and the spectral range of the light irradiation conditions is 420-780nm.

[0045] Specifically, the amount of the ligand-deficient MOF photocatalyst is 1%, 2%, 3%, 4%, 4.3%, 5% or 6% of the mass of the oil and fat; the molar ratio of methanol to oil and fat is 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 15.6:1, 16:1, 17:1, 18:1, 19:1 or 20:1; and the esterification reaction or transesterification reaction is carried out for 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 4.8h, 5h, 5.5h or 6h.

[0046] In the preferred embodiment of the present application, the oil and fat is at least one of oleic acid, palmitic acid, lauric acid, stearic acid, castor oil and palm oil.

[0047] The technical solutions described in the present application are conventional solutions in the art unless otherwise specified, and the reagents or raw materials used are purchased from commercial channels or are publicly known.

[0048] In order to better understand the present application, the content of the present application is further illustrated below in conjunction with examples, but the content of the present application is not limited to the examples below.

[0049] Example 1

[0050] 1. Preparation of ligand-deficient H-UiO-66-N-0.3 catalyst

[0051] Step 1: 542.3mg ZrOCl2·8H2O, 60mg 2-amino terephthalic acid and 140mg terephthalic acid were sequentially added to a solution of 10mL acetic acid and 10mL DMF, and stirred at room temperature for 4h. Then, the resulting mixed solution was loaded into a 100mL polytetrafluoroethylene liner, and the liner was sealed in a stainless steel hydrothermal kettle. The hydrothermal kettle was placed in a muffle furnace at 120℃ for 24h, and then naturally cooled to room temperature. The precipitate was collected by centrifugation at 9000rpm for 5min, and washed with ethanol three times. The precipitate was then dried under vacuum at 60℃ overnight. The obtained sample was labeled as UiO-66-N-0.3.

[0052] Step 2, the obtained UiO-66-N-0.3 sample was calcined at 350℃ for 2h in a muffle furnace, and after natural cooling to room temperature, the sample was activated at 60℃ for 12h to obtain the ligand-deficient H-UiO-66-N-0.3 catalyst.

[0053] 2. Catalytic activity test

[0054] 1g of oleic acid, H-UiO-66-N-0.3 catalyst (4% of the mass of oleic acid) and methanol (molar ratio of methanol to oleic acid was 15:1) were added into a quartz photo-reactor with a total volume of 10mL. After sealing, the obtained mixture was stirred at room temperature under visible light irradiation using a 300W Xe lamp (420nm>λ>780nm) as the light source for 4.5h. After the reaction was completed, the photocatalyst was recovered by centrifugation; then a rotary evaporator was used to remove methanol and water to obtain biodiesel.

[0055] The corresponding biodiesel yield was determined by gas chromatography, and the yield of biodiesel was calculated to be 87.02%.

[0056] Example 2

[0057] 1. Preparation of ligand-deficient H-UiO-66-N-0.2 catalyst

[0058] The preparation method of the ligand-deficient H-UiO-66-N-0.3 catalyst in Example 1 was the same, except that 60mg of 2-amino terephthalic acid and 140mg of terephthalic acid were replaced by 40mg of 2-amino terephthalic acid and 160mg of terephthalic acid to obtain the ligand-deficient H-UiO-66-N-0.2 catalyst.

[0059] 2. Catalytic activity test

[0060] The catalytic activity test part in Example 1 was the same, and the yield of biodiesel was calculated to be 82.2%.

[0061] Example 3

[0062] 1. Preparation of ligand-deficient H-UiO-66-N-0.4 catalyst

[0063] The preparation method of the ligand-deficient H-UiO-66-N-0.3 catalyst in Example 1 was the same, except that 60mg of 2-amino terephthalic acid and 140mg of terephthalic acid were replaced by 80mg of 2-amino terephthalic acid and 120mg of terephthalic acid to obtain the ligand-deficient H-UiO-66-N-0.4 catalyst.

[0064] 2. Catalytic activity test

[0065] The yield of biodiesel was calculated to be 84.8% in the same way as the catalytic activity test part in Example 1.

[0066] Comparative Example 1

[0067] 1. Preparation of UiO-66-N-0.3 catalyst

[0068] The same as the preparation method of ligand-deficient H-UiO-66-N-0.3 catalyst in Example 1, except that in step 2, the step of constant temperature calcination at 350℃ for 2h was omitted, to obtain the UiO-66-N-0.3 catalyst.

[0069] 2. Catalytic activity test

[0070] The yield of biodiesel was calculated to be 54.8% in the same way as the catalytic activity test part in Example 1.

[0071] Comparative Example 2

[0072] 1. Preparation of UiO-66-N-0.2 catalyst

[0073] The same as the preparation method of ligand-deficient H-UiO-66-N-0.2 catalyst in Example 2, except that in step 2, the step of constant temperature calcination at 350℃ for 2h was omitted, to obtain the UiO-66-N-0.2 catalyst.

[0074] 2. Catalytic activity test

[0075] The yield of biodiesel was calculated to be 46.58% in the same way as the catalytic activity test part in Example 1.

[0076] Comparative Example 3

[0077] 1. Preparation of UiO-66-N-0.4 catalyst

[0078] The same as the preparation method of ligand-deficient H-UiO-66-N-0.4 catalyst in Example 3, except that in step 2, the step of constant temperature calcination at 350℃ for 2h was omitted, to obtain the UiO-66-N-0.4 catalyst.

[0079] 2. Catalytic activity test

[0080] The yield of biodiesel was calculated to be 48.26% in the same way as the catalytic activity test part in Example 1.

[0081] Comparative Example 4

[0082] 1. Preparation of H-UiO-66 catalyst

[0083] The preparation method of the ligand-deficient H-UiO-66-N-0.3 catalyst in Example 1 is the same, except that in step 1, the addition of 2-amino terephthalic acid is omitted, to obtain the H-UiO-66 catalyst.

[0084] 2. Catalytic activity test

[0085] The yield of biodiesel is calculated to be 59.72% according to the catalytic activity test part in Example 1.

[0086] Comparative Example 5

[0087] 1. Preparation of the UiO-66 catalyst

[0088] The preparation method of the ligand-deficient H-UiO-66-N-0.3 catalyst in Example 1 is the same, except that in step 1, the addition of 2-amino terephthalic acid is omitted, and in step 2, the step of constant temperature calcination at 350 DEG C for 2h is omitted, to obtain the UiO-66 catalyst.

[0089] 2. Catalytic activity test

[0090] The yield of biodiesel is calculated to be 31.17% according to the catalytic activity test part in Example 1.

[0091] Comparative Example 6

[0092] 1. Preparation of the unactivated H-UiO-66-N-0.3 catalyst

[0093] The preparation method of the ligand-deficient H-UiO-66-N-0.3 catalyst in Example 1 is the same, except that in step 2, the step of constant temperature activation at 60 DEG C for 12h is omitted, to obtain the unactivated H-UiO-66-N-0.3 catalyst.

[0094] 2. Catalytic activity test

[0095] The yield of biodiesel is calculated to be 63.54% according to the catalytic activity test part in Example 1.

[0096] Example 4

[0097] In order to explore the best reaction conditions of the catalyst in the photocatalytic preparation of biodiesel from oil, on the basis of the catalytic activity test in Example 1, the reaction time under visible light irradiation, the molar ratio of methanol and oleic acid, and the mass percentage of the catalyst in oleic acid are adjusted respectively, and the yield of biodiesel is calculated, which is specifically:

[0098] (1) The same as the catalytic activity test in Example 1, the difference is only that the stirring time of the obtained mixture at room temperature is adjusted from 4.5h to 4.8h and 5h respectively. When the reaction time is 4.8h, the calculated yield of biodiesel is 95.33%, and when the reaction time is 5h, the calculated yield of biodiesel is 94.72%.

[0099] (2) The same as the catalytic activity test in Example 1, the difference is only that the molar ratio of methanol and oleic acid is adjusted from 15:1 to 15.6:1. The calculated yield of biodiesel is 96.14%.

[0100] (3) The same as the catalytic activity test in Example 1, the difference is only that the proportion of catalyst in the mass of oleic acid is adjusted from 4% to 4.3%. The calculated yield of biodiesel is 93.46%.

[0101] (4) The reaction conditions obtained by response surface optimization are 4.8h, 4.3wt%, 15.6:1, that is, the stirring time of the obtained mixture at room temperature is 4.8h, the proportion of catalyst in the mass of oleic acid is 4.3%, and the molar ratio of methanol and oleic acid is 15.6:1, the highest yield of biodiesel can be obtained, and the yield of biodiesel is 96.95%.

[0102] Characterization results:

[0103] Figure 1 The XRD spectra of different samples of the application, wherein the position of the characteristic peak does not shift obviously, indicating that the framework structure of the material is still retained.

[0104] Figure 2 The Fourier infrared spectra of different samples of the application. The band near 770cm -1 corresponds to the C-NH2 bond, indicating that the heat-sensitive ligand 2-amino terephthalic acid is successfully connected to the structural framework. The stretching vibration absorption peak at 549cm -1 is attributed to Zr 4+ -(OC) bond produced by the interaction of terephthalic acid or 2-amino terephthalic acid ligand, proving the successful synthesis of the material. Compared with the spectra of the catalyst before and after calcination, the characteristic peak intensity of H-UiO-66-N is obviously weaker than that of UiO-66-N, indicating that the 2-amino terephthalic acid ligand decomposes during the calcination process.

[0105] Figure 3 The nitrogen adsorption and desorption and pore size distribution spectra of different samples in the application. Among them, the UiO-66-N material shows a type of N2 adsorption and desorption curve of type I curve, and the main adsorption area is microporous region. After heat treatment, the type of adsorption and desorption curve changes to type IV, and the material changes from microporous to mesoporous.

[0106] Figure 4 Scanning electron microscope images of different catalysts prepared in the present application. In the scanning electron microscope images, the relative proportion of the different elements in the sample is shown. Figure 4 The H-UiO-66-N-0.3 in the present application has a larger surface area and pore volume than the UiO-66 in a. Figure 4 The H-UiO-66-N-0.3 in b presents a rougher surface, which is beneficial for the adsorption of substrates. Figure 4 The transmission electron microscope results of the H-UiO-66-N-0.3 in c show the formation of internal defects, which changes the structure of the ligand. Figure 4 The EDS images of d and e show that the H-UiO-66-N-0.3 still maintains the original framework structure after pyrolysis, and the main elements Zr, C, N and O are uniformly distributed in the sample.

[0107] Figure 5 UV-Vis diffuse reflectance spectra of different samples in the present application. This shows that the formation of defects in the catalyst can effectively adjust the band gap of the photocatalytic material.

[0108] Figure 6 Response surface optimization diagram of the H-UiO-66-N-0.3 catalyst catalyzing the esterification reaction of oleic acid and methanol, and radar chart of the catalytic performance of the catalyst in different substrates. a shows that the best biodiesel yield is obtained when the reaction time is 4.8h and the catalyst amount is 4.3wt%; b shows that the best biodiesel yield is obtained when the reaction time is 4.8h and the molar ratio of alcohol to oil is 15.6:1; c shows that the best biodiesel yield is obtained when the catalyst amount is 4.3wt% and the molar ratio of alcohol to oil is 15.6:1; d shows that the H-UiO-66-N-0.3 has a higher biodiesel yield when used in free fatty acid as substrate; e shows that the catalyst still maintains good activity after being used for five times.

[0109] In summary, the catalyst material prepared by the preparation method of the present application has a large number of mesoporous pore structure, a large specific surface area and pore volume, and an adjustable energy band structure, which effectively promotes the rapid separation of photo-generated carriers, thereby improving the high photocatalytic activity. When the catalyst is applied to the photocatalytic preparation of biodiesel from oleic acid, the yield of biodiesel reaches 96.95% under the conditions of a methanol / oleic acid molar ratio of 15.6:1, a catalyst amount of 4.3wt% and a reaction time of 4.8h. In addition, the catalyst also shows good substrate versatility and reusability in the preparation of biodiesel from other oils and fats.

[0110] The above only describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered within the scope of protection of the present application.

Claims

1. A method for preparing a ligand-deficient MOF photocatalyst, characterized in that, The method comprises the following steps: subjecting a zirconium precursor, 2-amino terephthalic acid and terephthalic acid to a solvothermal reaction in a solvent to obtain a catalyst precursor; subjecting the catalyst precursor to calcination treatment and activation treatment in sequence to obtain the ligand-deficient MOF photocatalyst.

2. The production method according to claim 1, characterized by, The zirconium precursor is ZrOCl2·8H2O; the molar ratio of the zirconium precursor, 2-amino terephthalic acid and terephthalic acid is 1:(0.1-0.4):(0.3-0.8); and the solvent is a mixed solution of acetic acid and DMF in a volume ratio of 1:(0.5-2.0).

3. The preparation method according to claim 1, characterized in that, The solvothermal reaction is performed at a temperature of 100-150℃ for 12-36h.

4. The production method according to claim 1, characterized by, After the solvothermal reaction, the method further comprises the steps of centrifuging the obtained reaction solution, collecting the solid product and drying the solid product; the centrifuging is performed at a speed of 8000-10000rpm; and the drying is performed at a temperature of 60-80℃.

5. The preparation method according to claim 1, characterized in that, The calcination treatment is performed at a temperature of 300-400℃ for 1-5h.

6. The method of claim 1, wherein, The activation treatment is performed at a temperature of 60-120℃ for 12-24h.

7. A ligand-deficient MOF photocatalyst prepared by the preparation method of any one of claims 1-6.

8. Use of the ligand-deficient MOF photocatalyst of claim 7 in the photocatalytic preparation of biodiesel from oil.

9. Use according to claim 8, characterized in that, The esterification reaction or transesterification reaction is performed at room temperature and under light irradiation to prepare biodiesel from oil, methanol and the ligand-deficient MOF photocatalyst of claim 7.

10. Use according to claim 9, characterized in that, The amount of the ligand-deficient MOF photocatalyst is 1-6% of the mass of the oil; the molar ratio of the methanol and the oil is (5-20):1; the esterification reaction or transesterification reaction is performed for 1-6h; and the light irradiation is performed in a spectral range of 420-780nm.

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