A composite material of a nickel modified MOF material surface loaded with palladium and a preparation method and application thereof

Abstract

This invention belongs to the field of nanocomposite materials technology, specifically relating to a nickel-modified MOF material with palladium loaded on its surface, its preparation method, and its application. The preparation method of the nickel-modified MOF material UIO-66-NH2 with palladium loaded on its surface involves adding zirconium chloride, 2-aminoterephthalic acid, nickel nitrate hexahydrate, and sodium chloropalladate to a mixed solution of N,N-dimethylformamide, formic acid, and acetic acid. After stirring evenly, the solution is transferred to a high-pressure reactor and heated at high temperature. The resulting product is then centrifuged and dried. This invention's nickel-modified MOF material UIO-66-NH2 with palladium loaded on its surface is a novel composite material with controllable structure, excellent performance, and good thermal stability. It exhibits good performance in the thermocatalytic hydrogenation reduction of carbon dioxide. The raw materials used in its preparation method are inexpensive and readily available, the experimental operation is simple, and it does not require expensive equipment, thus facilitating industrial production.

Description

Technical Field

[0001] This invention belongs to the field of nanocomposite materials technology, specifically relating to a composite material with palladium loaded on the surface of a nickel-modified MOF material, its preparation method, and its application. Background Technology

[0002] Energy is a crucial guarantee for promoting social development and scientific and technological progress. With economic development and rapid industrialization, people are facing an increasingly serious energy shortage problem. Thermocatalytic carbon dioxide hydrogenation to produce high-value-added liquid fuels has significant potential in solving energy development issues. Currently, the thermocatalytic CO2 hydrogenation to formic acid reaction is mainly focused on the development of catalytic materials and the exploration of reaction mechanisms. Therefore, designing highly active catalytic materials has become a key focus.

[0003] Metal-organic frameworks (MOFs) have stood out due to their unique semiconductor properties, porous structure, high specific surface area, and extremely high carbon dioxide storage capacity, and have therefore been widely used in the development of carbon dioxide adsorption and conversion in recent years. Furthermore, because metals supported on MOFs exhibit good thermal stability, catalytic performance, and gas adsorption properties, their application in the catalytic reaction of carbon dioxide hydrogenation has also been extensively studied.

[0004] Among supported metal nanoparticles, Au, Pd, and Pt are commonly used. Pd-based catalysts exhibit excellent activity because Pd nanoparticles can provide metal sites for H2 dissociation and adsorption, and interfacial sites for CO2 adsorption and hydrogenation, thus they are widely used in CO2 hydrogenation reactions. Loading metal nanoparticles onto metal-organic frameworks (MOFs) not only reduces material utilization costs but also promotes carrier separation and electron transfer, thereby improving the efficiency of thermocatalysis. Summary of the Invention

[0005] To improve the activity of catalytic materials, this invention provides a composite material of nickel-modified MOF material UIO-66-NH2 with palladium supported on its surface, which can effectively promote carrier separation and electron transfer and can be widely used in the field of thermocatalytic carbon dioxide hydrogenation.

[0006] This application provides the following technical solution:

[0007] This invention provides a method for preparing a composite material with palladium loaded on the surface of a nickel-modified MOF material, comprising the following steps:

[0008] S11: Zirconium chloride, 2-aminoterephthalic acid, nickel nitrate and sodium chloropalladium are mixed in a mixed solution and then heated at high temperature to obtain the reaction product; the mixed solution is composed of N,N-dimethylformamide, formic acid and acetic acid;

[0009] S12: The reaction product is centrifuged and dried to obtain the composite material of nickel-modified MOF material with palladium loaded on the surface.

[0010] Preferably, in step S11, the molar ratio of zirconium chloride to 2-aminoterephthalic acid is 2-3:3-4.

[0011] Preferably, in step S11, the molar ratio of zirconium chloride to 2-aminoterephthalic acid is 2:3.

[0012] Preferably, in step 11, the amount of nickel nitrate used is 0.2-1.4 mmol.

[0013] Preferably, in step S11, the mass of sodium chloropalladium is 1-3% of that of zirconium chloride.

[0014] Furthermore, in step S11, the mass of sodium chloropalladium is 2% of that of zirconium chloride.

[0015] Furthermore, the amount of nickel nitrate hexahydrate used in step S11 is 0.2-1.4 mmol, preferably 1.0 mmol.

[0016] Preferably, the volume ratio of N,N-dimethylformamide, formic acid, and acetic acid in the step is 10-50:2-5:2-5.

[0017] Furthermore, the amount of N,N-dimethylformamide used in the above steps is 10-50 mL, preferably 50 mL.

[0018] Furthermore, in the above steps, the amount of formic acid and acetic acid used is 2-5 mL, preferably 5 mL.

[0019] Preferably, in step S11, the high-temperature heating temperature is 120-140℃.

[0020] Furthermore, in step S11, the high-temperature heating temperature is 130°C.

[0021] Preferably, in step S11, the high-temperature heating time is 20-28 hours.

[0022] Preferably, in step S11, the high-temperature heating time is 24 hours.

[0023] Preferably, in step S11, the reaction product obtained by high-temperature heating is washed clean with water and ethanol.

[0024] Preferably, in step S12, the drying temperature is 50-80℃ and the drying time is 10-12h.

[0025] Furthermore, in step S12, the drying temperature is 60°C and the drying time is 12 hours.

[0026] Specifically, the preparation method of the composite material with palladium loaded on the surface of the nickel-modified MOF material UIO-66-NH2 may include the following steps:

[0027] Zirconium chloride and 2-aminoterephthalic acid in a molar ratio of 2:3, 0.2–1.4 mmol of nickel nitrate hexahydrate, and 1%–3% sodium chloropalladate (based on the amount of zirconium chloride) were added to a mixed solution of N,N-dimethylformamide, 5 mL of formic acid, and acetic acid. After stirring evenly, the mixture was transferred to a high-pressure reactor and heated at 130 °C for 24 hours. The resulting product was then centrifuged and dried to obtain the nickel-modified MOF material UIO-66-NH2 surface-loaded palladium composite material.

[0028] The present invention also provides a composite material of nickel-modified MOF material with palladium loaded on the surface prepared by the above preparation method.

[0029] This invention also provides a method for the thermocatalytic hydrogenation reduction of carbon dioxide to produce formate, using the above-mentioned nickel-modified MOF material surface-loaded palladium composite material, comprising the following steps:

[0030] Under an inert atmosphere, a composite material with palladium loaded on the surface of a nickel-modified MOF material was added to a saturated sodium bicarbonate aqueous solution, heated and mixed, and then a mixed gas was added. The mixture was reacted at 40-100℃ for 0.5-1.5 h to obtain formic acid; the mixed gas consisted of carbon dioxide and hydrogen.

[0031] This invention uses zirconium chloride and 2-aminoterephthalic acid as precursors, and N,N-dimethylformamide, formic acid, and acetic acid as solvents. A simple hydrothermal method is used to encapsulate nickel nanoparticles and palladium single atoms within a MOF material, preparing a nickel-modified UIO-66-NH2 composite material with palladium supported on its surface. Nickel nitrate and sodium chloropalladate serve as the nickel and palladium sources, respectively, and acetic acid is used to adjust the solution pH to make it weakly acidic. The modification promotes carrier separation and electron transfer, significantly improving the thermocatalytic performance.

[0032] The technical solution of the present invention has the following advantages compared with the prior art:

[0033] 1. The method for preparing palladium-loaded composite materials on the surface of nickel-modified MOF material UIO-66-NH2 disclosed in this invention uses low-cost and readily available raw materials, is simple to operate, and does not use expensive equipment, which is conducive to industrial production.

[0034] 2. The palladium-loaded composite material on the surface of nickel-modified MOF material UIO-66-NH2 disclosed in this invention is a novel composite material with controllable structure, excellent performance and good thermal stability. It has excellent performance in thermocatalytic carbon dioxide hydrogenation reduction and is conducive to industrial application. Attached Figure Description

[0035] Figure 1 Transmission electron microscopy (TEM) image of the palladium-supported nickel-modified UIO-66-NH2 (Pd@UIO-66-NH2(Ni)) composite material of Example 1;

[0036] Figure 2 The image shows a scanning electron microscope (SEM) image of the palladium-supported nickel-modified UIO-66-NH2 (Pd@UIO-66-NH2(Ni)) composite material from Example 1.

[0037] Figure 3 This is a diagram illustrating the effect of thermocatalytic carbon dioxide hydrogenation reduction to formate production using the palladium-supported nickel-modified UIO-66-NH2 (Pd@UIO-66-NH2(Ni)) composite material from Example 1. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0039] Example 1

[0040] The specific steps for preparing palladium-supported nickel-modified UIO-66-NH2 (Pd@UIO-66-NH2(Ni)) are as follows:

[0041] 93.2 mg of zirconium chloride, 108.7 mg of 2-aminoterephthalic acid, 0.2-1.4 mmol of nickel nitrate hexahydrate, and 2.1 mg of sodium chloropalladate were added to a mixed solution of N,N-dimethylformamide, formic acid, and acetic acid in 50 mL of water. The mixture was stirred vigorously at room temperature until homogeneous, then transferred to a high-pressure reactor and heated at 130 °C for 24 hours. The resulting product was washed with ethanol and distilled water, and then dried in a drying oven to obtain the nickel-modified MOF material UIO-66-NH2 with palladium loaded on its surface. A TEM image of the obtained Pd@UIO-66-NH2(Ni) is shown below. Figure 1 As shown, the SEM image is as follows: Figure 2 As shown in the figure, the octahedral structure was successfully prepared and is of uniform size.

[0042] Example 2

[0043] 33.4 mg of zirconium chloride, 27.3 mg of 2-aminoterephthalic acid, 0.2–1.4 mmol of nickel nitrate hexahydrate, and 0.84 mg of sodium chloropalladate were added to a mixed solution of 10 mL of N,N-dimethylformamide, 2 mL of formic acid, and acetic acid. The mixture was stirred vigorously at room temperature until homogeneous, and then transferred to a high-pressure reactor and heated at 130 °C for 24 hours. The resulting product was washed with ethanol and distilled water and then dried in a drying oven to obtain a nickel-modified MOF material, UIO-66-NH2, with palladium supported on its surface.

[0044] Example 3

[0045] 300 mg of zirconium chloride, 235 mg of 2-aminoterephthalic acid, 0.2–1.4 mmol of nickel nitrate hexahydrate, and 7.58 mg of sodium chloropalladate were added to a mixed solution of 30 mL of N,N-dimethylformamide, 2 mL of formic acid, and acetic acid. The mixture was stirred vigorously at room temperature until homogeneous, and then transferred to a high-pressure reactor and heated at 130 °C for 24 h. The resulting product was washed with ethanol and distilled water and then dried in a drying oven to obtain a nickel-modified MOF material, UIO-66-NH2, with palladium supported on its surface.

[0046] Application Example 1

[0047] The specific steps for testing the thermocatalytic carbon dioxide reduction performance under heating conditions are as follows:

[0048] The thermocatalytic carbon dioxide reduction activity of the composite material with palladium loaded on the surface of the nickel-modified MOF material UIO-66-NH2 obtained in Example 1 was evaluated using a magnetically heated stirrer.

[0049] 5 mg of the palladium-supported nickel-modified UIO-66-NH2 (Pd@UIO-66-NH2(Ni)) composite catalyst obtained in Example 1 was dispersed in 5 mL of saturated sodium bicarbonate ultrapure water by ultrasonic dispersion. The dispersion was then transferred to a magnetically heated stirrer and sealed. The air in the system was removed with an inert gas. After the reaction was completed, a carbon dioxide / hydrogen mixture of 1-3 MPa was injected into the reactor, and the reactor was heated to 40-100 °C for 1 h. The yield of formic acid was obtained by ion chromatography and analysis based on standard samples.

[0050] Figure 3 This is a graph showing the thermocatalytic carbon dioxide reduction performance of the palladium-supported nickel-modified UIO-66-NH2 (Pd@UIO-66-NH2(Ni)) composite material from Example 1. Figure 3 It is known that the palladium-supported nickel-modified UIO-66-NH2 (Pd@UIO-66-NH2(Ni)) composite material exhibits excellent thermocatalytic carbon dioxide reduction performance, with the optimal catalyst achieving a formic acid production efficiency of 60.7 molFAmolPd.-1 h -1 This composite material not only has excellent performance and good stability, but also has a simple preparation process, low raw material price, and is easy to industrialize.

[0051] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for the thermocatalytic hydrogenation reduction of carbon dioxide to produce formate, characterized in that, The composite material with palladium loaded on the surface of nickel-modified MOF material includes the following steps: Under an inert atmosphere, a composite material with palladium loaded on the surface of a nickel-modified MOF material is added to a saturated sodium bicarbonate aqueous solution. After heating and mixing, a mixed gas is added, and the reaction is carried out at 40-100℃ for 0.5-1.5 h to obtain formate. The mixed gas consists of carbon dioxide and hydrogen. The preparation method of the composite material with palladium loaded on the surface of the nickel-modified MOF material includes the following steps: S11: Zirconium chloride, 2-aminoterephthalic acid, nickel nitrate and sodium chloropalladium are mixed in a mixed solution and then heated at high temperature to obtain the reaction product; the mixed solution is composed of N,N-dimethylformamide, formic acid and acetic acid; in step S11, the high temperature heating is 120-140℃ and the high temperature heating time is 20-28 h; S12: The reaction product is centrifuged and dried to obtain the composite material with palladium loaded on the surface of the nickel-modified MOF material; in step S11, the molar ratio of zirconium chloride and 2-aminoterephthalic acid is 2-3:3-4; the mass of sodium chloropalladate in step S11 is 1-3% of zirconium chloride; the volume ratio of N,N-dimethylformamide, formic acid and acetic acid in the step is 10-50:2-5:2-5.

2. The method for producing formate by thermocatalytic hydrogenation reduction of carbon dioxide as described in claim 1, characterized in that, In step S11, the reaction product obtained by high-temperature heating is washed clean with water and ethanol.

3. The method for producing formate by thermocatalytic hydrogenation reduction of carbon dioxide as described in claim 1, characterized in that, In step S12, the drying temperature is 50-80℃ and the drying time is 10-12 h.

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