Application of composite materials as photothermal catalysts in selective reduction reactions

Abstract

The present invention discloses a composite material for use as a photothermal catalyst in a selective reduction reaction. The composite material comprises carboxylic acid-functionalized carbon nanotubes and Zr-MOF coated on the surface of the carboxylic acid-functionalized carbon nanotubes. The surface of the composite material contains 0.8 to 3 at % of zirconium. The composite material significantly improves the selectivity of the product, with selectivities exceeding 96%, and has excellent turnover frequency and production rate. The composite material also avoids the use of precious metals, eliminates the need for external heating, and reduces reaction energy consumption.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomass catalytic conversion, and specifically relates to the application of a composite material as a photothermal catalyst in a selective reduction reaction. Background Art

[0002] Furfural, as one of the important platform compounds obtained from the conversion of lignocellulosic biomass, occupies a key position in the catalytic conversion and utilization of biomass. Among them, the selective reduction of furfural to produce furfuryl alcohol has always been a hot research topic in the field of biomass catalytic conversion. According to statistics, about 60% of the world's furfural production is used to produce high-value-added furfuryl alcohol. At present, the industrial production of furfural selective reduction to produce furfuryl alcohol mainly adopts the traditional high-pressure hydrogenation method with molecular hydrogen as the hydrogen donor. Although the traditional high-pressure hydrogenation method is relatively mature, the use of high-pressure hydrogen poses a risk of hydrogen explosion in actual application, and the equipment is relatively complex, which makes the energy consumption and risk of furfuryl alcohol production relatively high. In addition, the chromium-based catalysts used in the traditional high-pressure hydrogenation method have environmental pollution risks and are not conducive to sustainable development.

[0003] In recent years, catalytic transfer hydrogenation has gradually attracted attention as an emerging technology for the selective reduction of furfural. Compared with traditional high-pressure hydrogenation methods, catalytic transfer hydrogenation uses inexpensive organic hydrogen donors (such as isopropanol and formic acid). This not only avoids the use of high-pressure hydrogen, reducing safety risks and equipment costs, but also completes the reaction under milder conditions, helping to reduce energy consumption. In catalytic transfer hydrogenation, traditional catalysts (including metals and solid acid-base materials) have demonstrated good catalytic activity in the selective reduction of furfural, but there are still some limitations in terms of selectivity and catalyst stability. For example, metal catalysts may catalyze over-hydrogenation or produce side reactions, resulting in reduced selectivity of the target product; while acid-base catalysts face problems such as catalyst deactivation and harsh reaction conditions, resulting in reduced catalytic efficiency.

[0004] Photothermal catalysts are catalytic materials that convert light energy into heat to promote chemical reactions. Among the many candidate materials, metal-organic frameworks (MOFs) have attracted considerable attention due to their tunable pore structure, excellent surface area, and chemical tunability. However, MOFs' poor light absorption and relatively weak mechanical stability limit their application in photothermal catalytic reactions. Therefore, there is an urgent need for a photothermal catalyst with excellent catalytic activity and stability to replace traditional catalysts for catalytic transfer hydrogenation. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a composite material for use as a photothermal catalyst in a selective reduction reaction, wherein a zirconium-based metal-organic framework (Zr-MOF) is synthesized using zirconium tetrachloride and 1, 3, 5-benzenetricarboxylic acid, and the Zr-MOF is coated on the surface of carboxylic acid-functionalized carbon nanotubes to obtain a composite material.

[0006] The purpose of the present invention is achieved through the following technical solutions.

[0007] A composite material is used as a photothermal catalyst in a selective reduction reaction. The composite material includes: carboxylic acid functionalized carbon nanotubes and a zirconium-based metal organic framework coated on the surface of the carboxylic acid functionalized carbon nanotubes. The zirconium element contained on the surface of the composite material is 0.8-3 at%.

[0008] In the above technical solution, the selective reduction reaction includes the following steps: uniformly mixing the composite material, reactants and a second solvent to obtain a reaction solution, irradiating the reaction solution with a light source for at least 2 hours under stirring, and cooling the reaction solution to room temperature after the reaction is completed to obtain a product.

[0009] In the above technical solution, the light source is 600~1300 mW / cm 2 Xenon lamp light intensity.

[0010] In the above technical solution, the reactants include: a mixture of one or more of furfural, 5-hydroxymethylfurfural, benzaldehyde and 1,4-benzenedicarboxaldehyde.

[0011] In the above technical solution, when the reactant includes furfural, the product includes furfuryl alcohol; when the reactant includes 5-hydroxymethylfurfural, the product includes 5-hydroxymethylfurfural; when the reactant includes benzaldehyde, the product includes benzyl alcohol; when the reactant includes 1,4-benzenedimethanol, the product includes 1,4-benzenedimethanol.

[0012] In the above technical solution, the second solvent includes: isopropyl alcohol.

[0013] In the above technical solution, the zirconium-based metal organic framework is synthesized by zirconium tetrachloride and 1, 3, 5-benzenetricarboxylic acid, and is combined with the carboxyl functional groups on the surface of the carboxylic acid functionalized carbon nanotubes through Zr-O coordination bonds to achieve the coating.

[0014] The method for preparing the composite material comprises the following steps:

[0015] Carboxylic acid-functionalized carbon nanotubes, zirconium tetrachloride, 1,3,5-benzenetricarboxylic acid, and a first solvent are uniformly mixed to obtain a mixed solution, the mixed solution is stirred at 130-150°C for more than 2 hours (condensation reflux), cooled to room temperature, centrifuged, washed, and vacuum-dried in sequence to obtain a composite material; wherein, by weight, the ratio of carboxylic acid-functionalized carbon nanotubes, zirconium tetrachloride, and 1,3,5-benzenetricarboxylic acid is (1-3):(2-4):1.

[0016] In the above technical solution, carboxylic acid functionalized carbon nanotubes are dispersed in a first solvent by ultrasound to obtain a carbon nanotube solution, zirconium tetrachloride and 1, 3, 5-benzenetricarboxylic acid are added to the carbon nanotube solution, and ultrasound is applied until the mixture is uniformly mixed to obtain a mixed solution.

[0017] In the above technical solution, the first solvent is a mixture of N, N-dimethylformamide and formic acid.

[0018] In the above technical solution, the ratio of the mass fraction of carboxylic acid functionalized carbon nanotubes, the volume fraction of N, N-dimethylformamide in the first solvent, and the volume fraction of formic acid in the first solvent is (1~2.5):0.5:0.5, the unit of the mass fraction is mg, and the unit of the volume fraction is mL.

[0019] In the above technical solution, the frequency of the ultrasound is 20~60kHz, and the time of the ultrasound is 0.5~1h.

[0020] In the above technical solution, the stirring speed is 100~3000 r / min.

[0021] In the above technical solution, the centrifugal speed is 5000-8000 rpm, and the centrifugal time is 3-10 min.

[0022] In the above technical solution, the washing operation includes: washing with N, N-dimethylformamide and methanol alternately for at least 3 times each.

[0023] In the above technical solution, the vacuum drying temperature is 60~90℃, and the vacuum drying time is 12~18 hours.

[0024] The composite material of the present invention greatly improves the selectivity of the reduction of reactants (such as furfural) to products (such as furfuryl alcohol), and the selectivity is above 96%. It has an excellent turnover frequency (804.2 h -1 ) and production rate (57.1 mmol g -1 h -1 ), and the composite material of the present invention avoids the use of precious metals, does not require external heating, and reduces reaction energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 TEM images, wherein (a) is the MOF material prepared in Comparative Example 1, and (b) is the composite material prepared in Example 1;

[0026] Figure 2 Elemental mapping of the composite material prepared in Example 1;

[0027] Figure 3 The XPS graphs of the Zr 3d peak of the composite materials prepared in Examples 1 to 4 and the Zr-MOF material prepared in Comparative Example 1;

[0028] Figure 4 XRD patterns of the composite materials prepared in Examples 1 to 4, the Zr-MOF material prepared in Comparative Example 1, and the CNT material prepared in Comparative Example 2;

[0029] Figure 5 Fourier transform infrared spectra of the composite material prepared in Example 1, the Zr-MOF material prepared in Comparative Example 1, and the CNT material prepared in Comparative Example 2;

[0030] Figure 6 The transmittance of the composite materials prepared in Examples 1 to 4, the Zr-MOF material prepared in Comparative Example 1, and the CNT material prepared in Comparative Example 2;

[0031] Figure 7 A comparison chart of the effects of selective reduction of furfural to furfuryl alcohol catalyzed by the composite materials prepared in Examples 1 to 4, the MOF material prepared in Comparative Example 1, the CNT material prepared in Comparative Example 2, and the mixed material prepared in Comparative Example 3;

[0032] Figure 8 (a-c) High-precision infrared thermographic images and (d) temperature curves for the selective reduction of furfural to furfuryl alcohol, where (a) is the composite material prepared in Example 1, (b) is the MOF material prepared in Comparative Example 1, and (c) is the mixed material prepared in Comparative Example 3.

[0033] Figure 9 This is a graph showing the effect-time curve of the selective reduction of furfural to furfuryl alcohol catalyzed by the composite material prepared in Example 1. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0035] Examples 1 to 4

[0036] A method for preparing a composite material comprises the following steps:

[0037] Carboxylic acid-functionalized carbon nanotubes (purchased from Beijing Bailingwei Technology Co., Ltd.) were dispersed in a first solvent (the first solvent was a mixture of N,N-dimethylformamide and formic acid) by ultrasonication at 40 kHz for 0.5 h to obtain a carbon nanotube solution. Zirconium tetrachloride and 1, 3, 5-benzenetricarboxylic acid were added to the carbon nanotube solution, and ultrasonication was again performed at 40 kHz for 0.5 h until the mixture was uniformly mixed to obtain a mixed solution. The mixed solution was stirred at 140°C for 2 h (condensation reflux) at 200 r / min, cooled to room temperature, and centrifuged at 6000 rpm for 5 min to obtain a black precipitate. The precipitate was alternately rinsed with N, N-dimethylformamide and methanol three times each and dried in a 70°C oven under vacuum for 12 h to obtain a composite material. The ratio of carboxylic acid-functionalized carbon nanotubes, zirconium tetrachloride, and 1, 3, 5-benzenetricarboxylic acid, by mass, was G; the ratio of the mass fraction of carboxylic acid-functionalized carbon nanotubes, the volume fraction of N, N-dimethylformamide in the first solvent, and the volume fraction of formic acid in the first solvent was W, with the units of mass fraction being mg and volume fraction being mL.

[0038] The G, W and numbers of the composite materials prepared in Examples 1 to 4 are shown in Table 1.

[0039] Table 1

[0040]

[0041] Comparative Example 1

[0042] A method for preparing a MOF material (code: Zr-MOF) comprises the following steps:

[0043] 522.0 mg of zirconium tetrachloride and 495.3 mg of 1, 3, 5-benzenetricarboxylic acid were dissolved in 60 mL of a first solvent (a mixture of N,N-dimethylformamide and formic acid) and stirred for 30 min until uniformly mixed to obtain a MOF solution. The MOF solution was placed in a hydrothermal reactor and stirred at 115°C for 24 h. After the reaction, it was cooled to room temperature and centrifuged at 6000 rpm for 5 min to obtain a white solid. The solid was washed alternately with N,N-dimethylformamide and methanol three times each and dried in a vacuum oven at 70°C for 12 h to obtain a MOF material (number: Zr-MOF). The ratio of N,N-dimethylformamide in the first solvent to formic acid in the first solvent was 1:1 by volume.

[0044] Comparative Example 2

[0045] A CNT material (number: CNT), which is a carboxylic acid functionalized carbon nanotube, was purchased from Beijing Bailingwei Technology Co., Ltd.

[0046] Comparative Example 3

[0047] A method for preparing a hybrid material (code: MOF@CNT) comprises the following steps:

[0048] The MOF material prepared in Comparative Example 1 and the carboxylic acid functionalized carbon nanotubes were uniformly mixed to obtain a mixed material (number: MOF@CNT), wherein the ratio of the MOF material prepared in Comparative Example 1 to the carboxylic acid functionalized carbon nanotubes was 2:3 by mass.

[0049] Comparative Example 4

[0050] A photothermal material, see "A-sheet" in Wu, X.; Li, J.; Xie, S.; Duan, P.; Zhang, H.; Feng, J.; Zhang, Q.; Cheng, J.; Wang, Y., Selectivity Control inPhotocatalytic Valorization of Biomass-Derived Platform Compounds by SurfaceEngineering of Titanium Oxide. Chem 2020, 6 (11), 3038-3053.

[0051] Comparative Example 5

[0052] A photothermal material, see Chen, G.; Fu, C.; Zhang, W.; Gong, W.; Ma, J.; Ji, X.; Qian, L.; Feng, X.; Hu, C.; Long, R.; Xiong, Y., Solar-drivenproduction of renewable chemicals via biomass hydrogenation with greenmethanol. Nature Communications 2025, 16 (1) SAs -TiO2".

[0053] Comparative Example 6

[0054] A photothermal material, see “Cu / Cu2O-MC” in Zhang, M.; Li, Z., Cu / Cu2O-MC (MC = Mesoporous Carbon) for Highly Efficient Hydrogenation of Furfural to Furfuryl Alcohol under Visible Light. ACS Sustainable Chemistry&Engineering 2019, 7 (13), 11485-11492.

[0055] Comparative Example 7

[0056] A photothermal material, see “Pd / MIL-101(Fe)-NH2” in Dong, S.; Liu, Z.; Liu, R.; Chen, L.; Chen, J.; Xu, Y., Visible-Light-Induced Catalytic Transfer Hydrogenation of AromaticAldehydes by Palladium Immobilized on Amine-Functionalized Iron-Based Metal-Organic Frameworks. ACS Applied Nano Materials 2018, 1 (8), 4247-4257.

[0057] Comparative Example 8

[0058] A photothermal material, see “Au / SiC” in Cai-Hong, H.; Xiao-Ning, G.; Yung-Tin, P.; Shuai, C.; Zhi-Feng, J.; Hong, Y.; Xiang-Yun, G., Visible-Light-DrivenSelective Photocatalytic Hydrogenation of Cinnamaldehyde over Au / SiC Catalysts. Journal of the American Chemical Society 2016, 138 (30), 9361-4.

[0059] Comparative Example 9

[0060] A catalytic material, see the reference Feng, Y.; Long, S.; Chen, B.; Jia, W.; Xie, S.; Sun, Y.; Tang, X.; Yang, S.; Zeng, X.; Lin, L., Inducing Electron Dissipationof Pyridinic N Enabled by Single Ni-N4Sites for the Reduction of Aldehydes / Ketones with Ethanol. ACS Catalysis 2021, 11 (11), 6398-6405. 2.1 / CN”.

[0061] Comparative Example 10

[0062] A catalytic material, see “Zr1Al3-MMO” in the literature Ye, L.; Han, Y.; Xi, J.; Wang, X.; Lu, X., Differences of Short Straight-Chain Monoalcohols in the Value-AddedConversion of Furfural Catalyzed by Zr3Al1-MMO: Effect of Hydroxyl Positionand Carbochain Length. ACS Sustainable Chemistry and Engineering 2021, 9(39), 13312-13323.

[0063] The composite material prepared in Example 1 and the MOF material prepared in Comparative Example 1 were subjected to TEM. Figure 1 As shown; the composite material prepared in Example 1 was subjected to element mapping as shown Figure 2 As shown. Figure 1 From (a), it can be seen that the MOF material prepared in Comparative Example 1 is composed of irregular nano-scale Zr-MOF particles. Figure 1 From (b), we can see that in the composite material prepared in Example 1, the Zr-MOF synthesized from zirconium tetrachloride and 1, 3, 5-benzenetricarboxylic acid is coated on the surface of the carboxylic acid functionalized carbon nanotubes. Figure 2 It can be seen that the C element, the O element and the zirconium (Zr) element are evenly distributed in the composite material prepared in Example 1.

[0064] The atomic percentages of the surface elements of the composite materials prepared in Examples 1 to 4 and the MOF material prepared in Comparative Example 1 were further analyzed by XPS, and the results are shown in Table 2. As can be seen from Table 2, the content of Zr species exposed on the surface of the material in Example 1 is the highest.

[0065] Table 2

[0066]

[0067] The XPS analysis of the Zr 3d peak of the composite materials prepared in Examples 1 to 4 and the Zr-MOF material prepared in Comparative Example 1 is as follows: Figure 3 As shown by Figure 3 It can be seen that the composite materials prepared in Examples 1 to 4 all have the characteristic double peaks of Zr element Zr 3d 5 / 2 and Zr 3d 3 / 2 .

[0068] The specific surface area, mesopore volume and average mesopore diameter of the composite materials prepared in Examples 1 to 4, the Zr-MOF material prepared in Comparative Example 1 and the CNT material prepared in Comparative Example 2 are shown in Table 3.

[0069] Table 3

[0070]

[0071] As can be seen from Table 3, compared with Comparative Example 2 (carboxylic acid functionalized carbon nanotubes), the specific surface area of ​​the composite materials prepared in Examples 1 to 4 is increased. Among the composite materials prepared in Examples 1 to 4, the composite material prepared in Example 1 has the largest specific surface area. The increase in specific surface area can enhance the mass transfer capacity with the reactants in the selective reduction reaction, thereby helping to improve the catalytic performance.

[0072] XRD was performed on the composite materials prepared in Examples 1 to 4, the Zr-MOF material prepared in Comparative Example 1, and the CNT material prepared in Comparative Example 2. Figure 4 As shown by Figure 4 It can be seen that the composite materials prepared in Examples 1 to 4 show the diffraction peak of the carboxylic acid functionalized carbon nanotubes in Comparative Example 2. Compared with Comparative Example 1, the diffraction peak of the composite materials prepared in Examples 1 to 4 at 8° is weak, and the peak value decreases with the increase of the content of the coated carboxylic acid functionalized carbon nanotubes, indicating that the composite materials prepared in Examples 1 to 4 have lost part of the crystalline structure of Zr-MOF, which is different from the Figure 1 This is consistent with the analysis of (b) that Zr-MOF loses part of its particle structure. At the same time, the diffraction peak of Zr-MOF is not obvious because the carboxylic acid functionalized carbon nanotubes have a great influence on the structure.

[0073] The composite material prepared in Example 1, the Zr-MOF material prepared in Comparative Example 1 and the carbon nanotube material prepared in Comparative Example 2 were tested by Fourier transform infrared spectroscopy. Figure 5 As shown by Figure 5 It can be seen that according to the absorption peaks of Comparative Examples 1 and 2, the composite material prepared in Example 1 (No. 1MOF / CNT) has a peak absorption of 1375-1675 cm -1 The absorption peak between 3434 cm-1 is attributed to the -COOH group and aromatic ring vibration of 1, 3, 5-benzenetricarboxylic acid. -1 The absorption peak is attributed to the stretching vibration of OH in the carboxylic acid functionalized carbon nanotubes and the OH stretching vibration of the -OH group attached to the Zr node that can be replaced. Compared with Comparative Example 1, the characteristic peak of the Zr-O bond in the Zr node of the composite material prepared in Example 1 has a blue shift from 658 cm -1 Displacement reached 661 cm -1 The blue shift of the spectral band indicates that the Zr-O bond strength has been enhanced, which further confirms that the Zr in the composite material prepared in Example 1 in XPS has a higher positive charge and has stronger Lewis acidity.

[0074] The composite materials prepared in Examples 1 to 4, the Zr-MOF material prepared in Comparative Example 1, and the CNT material prepared in Comparative Example 2 were tested using an ultraviolet-visible-near-infrared spectrophotometer. The transmittances obtained were as follows: Figure 6 As shown by Figure 6 It can be seen that compared with Zr-MOF (Comparative Example 1), the light transmittance of the composite materials prepared in Examples 1 to 4 is significantly reduced, indicating that the composite materials of the present invention prepared by combining Zr-MOF with carboxylic acid functionalized carbon nanotubes have improved light absorption capacity.

[0075] Example 5

[0076] Selective reduction reaction (selective reduction of furfural to prepare furfuryl alcohol):

[0077] 50 mg of photothermal catalyst, 100 mg of reactant (furfural) and 5 mL of isopropanol were placed in a pressure bottle and mixed evenly to obtain a reaction solution. The reaction solution was stirred at a speed of 2500 r / min and heated at 1100 mW / cm 2A xenon lamp with a high illumination intensity was used as a light source to irradiate the reaction solution for 2 h. After the reaction was completed, the solution was cooled to room temperature and then filtered through a 0.22 μm filter membrane to obtain a product containing a product (the product was furfuryl alcohol), wherein the photothermal catalyst was one of the composite materials prepared in Examples 1 to 4, the MOF material prepared in Comparative Example 1, the CNT material prepared in Comparative Example 2, and the mixed material prepared in Comparative Example 3. The conversion rate of the reactant (the reactant was furfural) and the yield of the product (the product was furfuryl alcohol) were respectively obtained using a high performance liquid chromatograph, and the selectivity of the product was obtained according to the selectivity calculation formula. The selectivity calculation formula is shown below.

[0078]

[0079] The conversion rate of furfural (conversion rate of reactants), the yield of furfuryl alcohol (yield of products) and the selectivity of furfuryl alcohol (selectivity of products) using the composite materials prepared in Examples 1 to 4, the MOF material prepared in Comparative Example 1, the CNT material prepared in Comparative Example 2 and the mixed material prepared in Comparative Example 3 as photothermal catalysts are shown in Tables 4 and Figure 7 shown.

[0080] Table 4

[0081]

[0082] In the selective reduction reaction using the composite material prepared in Example 1, the MOF material prepared in Comparative Example 1, and the mixed material prepared in Comparative Example 3 as a "photothermal catalyst", a high-precision infrared temperature measuring thermal imager was used to monitor the temperature of the reaction solution. The temperature change of the reaction solution was as follows: Figure 8 As shown in (d), Figure 8 (d) shows that with 1100 mW / cm 2 After the xenon lamp irradiation, the temperature of the reaction liquid began to rise gradually, but after 25 minutes of irradiation, the temperature of the reaction liquid remained unchanged. When the reaction liquid was irradiated for 25 minutes, a high-precision infrared temperature measuring thermal imager was used to obtain its thermal image, such as Figure 8 As shown in (a)~(c), Figure 8 (a) to (c) can be used to obtain the reaction liquid temperature at the 25th minute of irradiation, as shown in Table 5.

[0083] Table 5

[0084]

[0085] Example 6

[0086] Referring to the “selective reduction reaction” in Example 5, the composite material prepared in Example 1 was used as a “photothermal catalyst” and stirred at a speed of 2500 r / min with a power of 1100 mW / cm 2The reaction solution was irradiated with a xenon lamp of high intensity for 2 h. The reaction solution was taken at the Tth minute of irradiation and the conversion rate of furfural and the yield of furfuryl alcohol in the product were determined by high performance liquid chromatography, respectively. T = 30 min, 60 min, 90 min and 120 min. The selectivity of furfuryl alcohol was obtained according to the selectivity calculation formula, and a time curve of the furfural reduction to furfuryl alcohol was drawn, as shown in FIG. Figure 9 As shown, combined Figure 8 (d) and Figure 9 It can be seen that after the 25th minute of irradiation, the temperature of the reaction liquid stabilized, and the irradiation time was linearly related to the conversion rate of furfural and the yield of furfuryl alcohol, respectively, indicating that during the entire reaction process, furfural was selectively converted into furfuryl alcohol without other side reactions.

[0087] Example 7

[0088] The composite material prepared in Example 1 was used as a "photothermal catalyst" and the selective reduction reaction in Example 5 was referred to. 5-Hydroxymethylfurfural, benzaldehyde and 1,4-benzenedicarboxaldehyde were used as reactants for selective reduction reactions. The reactants, products, conversion rates of the reactants, yields of the products and selectivity of the products are shown in Table 6.

[0089] Table 6

[0090]

[0091] Example 8

[0092] The composite material prepared in Example 1 was compared with reported photothermal catalysts (Comparative Examples 4-8) and catalytic materials (Comparative Examples 9-10) in the selective reduction reaction of furfural to furfuryl alcohol (reaction conditions are shown in Table 7). The yield, turnover frequency, and production rate of furfuryl alcohol are shown in Table 7.

[0093] Table 7

[0094]

[0095] Turnover frequency = amount of furfuryl alcohol / (number of active sites * reaction time);

[0096] Production rate = amount of furfuryl alcohol / (catalyst mass * reaction time);

[0097] As shown in Table 7, compared with the reported photothermal catalysts and catalytic materials, the composite material of the present invention not only has a furfuryl alcohol yield of 94%, but also has a higher turnover frequency and production rate.

[0098] The above is an exemplary description of the present invention. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacement that can be made by other skilled in the art without expending creative labor falls within the scope of protection of the present invention.

Claims

1. A composite material used as a photothermal catalyst in the selective reduction of aldehydes to alcohols, characterized in that: The composite material comprises carboxylic acid functionalized carbon nanotubes and a zirconium-based metal organic framework coated on the surface of the carboxylic acid functionalized carbon nanotubes. The zirconium element contained on the surface of the composite material is 0.8-3 at %. The selective reduction reaction comprises the following steps: uniformly mixing the composite material, reactants, and a second solvent to obtain a reaction solution; irradiating the reaction solution with a light source for at least 2 hours under stirring; and cooling the reaction solution to room temperature after the reaction is completed to obtain a product, wherein the reactants comprise a mixture of one or more of furfural, 5-hydroxymethylfurfural, benzaldehyde, and 1,4-benzenedicarboxaldehyde; and the second solvent comprises isopropyl alcohol. The preparation method of the composite material comprises the following steps: Carboxylic acid-functionalized carbon nanotubes, zirconium tetrachloride, 1, 3, 5-benzenetricarboxylic acid, and a first solvent are uniformly mixed to obtain a mixed solution, the mixed solution is stirred at 130-150°C for more than 2 hours, cooled to room temperature, centrifuged, washed, and vacuum-dried in sequence to obtain a composite material; wherein, by weight, the ratio of carboxylic acid-functionalized carbon nanotubes, zirconium tetrachloride, and 1, 3, 5-benzenetricarboxylic acid is (1-3):(2-4):1, and the first solvent is a mixture of N, N-dimethylformamide and formic acid.

2. The use according to claim 1, characterized in that The light source is 600~1300 mW / cm 2 Xenon lamp light intensity.

3. The use according to claim 1, characterized in that When the reactant includes furfural, the product includes furfuryl alcohol; when the reactant includes 5-hydroxymethylfurfural, the product includes 5-hydroxymethylfurfural; when the reactant includes benzaldehyde, the product includes benzyl alcohol; when the reactant includes 1,4-benzenedicarboxaldehyde, the product includes 1,4-benzenedimethanol.

4. The use according to claim 1, characterized in that The zirconium-based metal organic framework is synthesized by zirconium tetrachloride and 1,3,5-benzenetricarboxylic acid, and is combined with the carboxyl functional groups on the surface of the carboxylic acid functionalized carbon nanotubes through Zr-O coordination bonds to achieve the coating.

5. The use according to claim 4, characterized in that The carboxylic acid functionalized carbon nanotubes are dispersed in a first solvent by ultrasound to obtain a carbon nanotube solution. Zirconium tetrachloride and 1, 3, 5-benzenetricarboxylic acid are added to the carbon nanotube solution, and ultrasound is applied until the mixture is uniformly mixed to obtain a mixed solution.

6. The use according to claim 5, characterized in that The ratio of the mass fraction of the carboxylic acid functionalized carbon nanotubes, the volume fraction of N, N-dimethylformamide in the first solvent, and the volume fraction of formic acid in the first solvent is (1-2.5):0.5:0.5, the unit of the mass fraction is mg, and the unit of the volume fraction is mL.

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