Phosphating carbon film packaging structure P-Ni-coated C catalyst, preparation method and application

Abstract

The invention discloses a phosphating carbon film packaging structure P-Ni-C catalyst, a preparation method and application, and relates to the technical field of catalysts, the preparation method of the catalyst comprises the following steps: S1, nickel salt and terephthalic acid are subjected to a hydrothermal reaction in N, N-dimethylformamide, and a product obtained after the reaction is subjected to suction filtration, washing and drying to obtain an intermediate product; and S2, respectively placing NaH2PO2.H2O and the intermediate product in the upstream and downstream of a porcelain boat, and carrying out one-step carbonization and phosphorization to obtain the P-Ni-C catalyst. An organic ligand on the outer surface of the catalyst can form a carbon film, the catalyst based on the Ni-MOF packaging structure can prevent metal particles from clustering and gathering, the unique pore structure of the original structure can be reserved, meanwhile, the catalytic effect of the catalyst is further improved through phosphorization, and the catalytic effect of the catalyst is improved. The hydrodeoxygenation experiment in the aspect of biomass hydrothermal liquefaction is facilitated; meanwhile, the P-Ni-C catalyst has a porous structure, so that the P-Ni-C catalyst also has extremely high catalytic stability in a hydrothermal liquefaction experiment.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and in particular to a phosphide-carbon film-encapsulated P-Ni@C catalyst, its preparation method, and its application. Background Technology

[0002] Biomass is the only renewable organic aromatic carbon-containing resource in nature and is recognized worldwide as a zero-carbon energy source, making it a hot research topic in the energy field. In the utilization of biomass, there is a lignin-priority principle; therefore, converting lignin into platform compounds and liquid fuels is an efficient strategy to reduce energy demand.

[0003] Currently, the catalytic conversion of lignin using supported metal-based catalysts has become an effective strategy. Among these materials, noble metal catalysts, such as Ru, Rh, Pt, and Pd, exhibit high activity in the hydrogenation and depolymerization of lignin. However, their high price and limited reserves restrict their industrial application. Therefore, non-noble metals such as Cu, Ni, Fe, Co, and Zn have been widely used in the HDO reaction of lignin due to their economic benefits. Furthermore, researchers generally believe that the higher the dispersion of the metal, the more catalytic sites it has, and the better its catalytic effect. In addition, the synergistic effect between multiple metals also helps to improve the catalyst's performance. For example, transition metal phosphides, such as Ni2P, Co2P, Fe2P, and MoP, are considered promising catalysts for the HDO reaction of bio-oils due to their good thermal stability and high activity.

[0004] Improving the dispersibility of metals to enhance their catalytic performance through various methods has become a popular research topic, such as impregnation loading, anchoring with other metals and their oxides, and carbon film encapsulation. Among these, carbon film encapsulation is a promising technology. On the one hand, it can confine the metal within each carbon film space, which greatly improves the metal's dispersibility. On the other hand, this structure also facilitates the entry of reaction substrates and the extraction of products. Summary of the Invention

[0005] Based on the technical problems existing in the background technology, this invention proposes a phosphide carbon film encapsulated P-Ni@C catalyst, its preparation method and application. This catalyst has the advantages of high metal dispersion, strong catalytic activity, good catalytic stability, simple preparation method and no pollution.

[0006] The present invention proposes a method for preparing a P-Ni@C catalyst with a carbon phosphide film encapsulation structure, characterized by the following steps:

[0007] S1: Nickel salt and terephthalic acid are hydrothermally reacted in N,N-dimethylformamide. The product after the reaction is filtered, washed and dried to obtain the intermediate product.

[0008] S2: NaH2PO2·H2O and intermediate products are placed upstream and downstream of a ceramic boat for one-step carbonization and phosphating to obtain a P-Ni@C catalyst.

[0009] Preferably, the mass ratio of nickel salt to terephthalic acid in S1 is 1:0.1-10.

[0010] Preferably, the hydrothermal reaction in S1 is carried out at a temperature of 140-180℃ for 8-16 hours.

[0011] Preferably, the mass ratio of the intermediate product to NaH2PO2·H2O in S2 is 1:2-4.

[0012] Preferably, the temperature for one-step carbonization and phosphating in S2 is 250-450℃, and the holding time is 1-3h.

[0013] The present invention proposes a phosphide-encapsulated P-Ni@C catalyst, which is prepared by the above-described method.

[0014] The present invention relates to the application of the above-mentioned phosphoric carbon film encapsulated P-Ni@C catalyst in biomass hydrothermal liquefaction.

[0015] Mechanism of action:

[0016] Compared to other transition metals, Ni has a wider d-electron band and higher energy density, which allows nickel-based catalysts to significantly enhance hydrogen activation and adsorption of oxygen-containing functional groups, thereby improving the hydrodeoxygenation process in hydrothermal liquefaction reactions. Ni-MOFs are porous materials with a three-dimensional network structure formed by the coordination of metal centers and organic ligands. The structural framework of Ni-MOF materials is achieved through various combinations of metal sites and organic ligands, which greatly enhances the tunability of Ni-MOF materials, including the desired active sites, pore size, and acidity, which is the source of the catalytic performance of these materials.

[0017] The presence of phosphorus (P) has a ligand effect on Ni sites, thereby influencing the electronic and geometric properties of Ni atoms and promoting the adsorption of oxygen-containing functional groups and the cleavage of CO bonds. Electron transfer from Ni to P causes the P-OH groups in the Ni₂P phase to provide more oxygen for the adsorption of Ni atoms. Acid and Lewis acid sites play an important role in the hydrogenation of C=O bonds and the hydrogenolysis of CO.

[0018] The one-step carbonization and phosphating method combines the carbonization and phosphating processes into one, which is beneficial for the formation of Ni2P substances in the catalyst. In contrast, the two-step method of carbonization followed by phosphating reduces the porosity of the catalyst surface during the carbonization process, hindering the phosphating of Ni nanoparticles and thus reducing the catalyst activity compared to the one-step carbonization and phosphating method.

[0019] Beneficial technical effects of the present invention:

[0020] This invention utilizes Ni-MOF as a precursor to prepare a carbon film-encapsulated P-Ni@C catalyst via a one-step carbonization and phosphating process. The organic ligands on its surface form a carbon film. This Ni-MOF-encapsulated catalyst not only prevents the clustering and aggregation of metal particles but also retains the unique porous structure of the original catalyst. Simultaneous phosphating further enhances the catalytic effect, which is beneficial for hydrodeoxygenation experiments in biomass hydrothermal liquefaction. Furthermore, due to the porous structure of the P-Ni@C catalyst, it exhibits extremely high catalytic stability in hydrothermal liquefaction experiments. Attached Figure Description

[0021] Figure 1 This is a SEM image of the P-Ni@C catalyst prepared in Example 1 of this invention;

[0022] Figure 2 This is a SEM image of the P / Ni@C catalyst prepared in the comparative example according to the present invention.

[0023] Figure 3 A comparison of the catalytic activity of the P-Ni@C catalyst prepared in Example 1 of this invention and the P / Ni@C catalyst prepared in the comparative example in hydrothermal liquefaction experiments;

[0024] Figure 4 The results of the cycle performance test of the P-Ni@C catalyst prepared in Example 1 of this invention are shown. Detailed Implementation

[0025] The present invention will be further explained below with reference to specific embodiments.

[0026] Example 1

[0027] Weigh out 1.14g Ni(NO3)2·6H2O and 20ml DMF respectively and mix them together. Sonicate them together for 15min until a clear solution A is formed.

[0028] Weigh out 0.44g of terephthalic acid and 20ml of DMF and mix them together. Sonicate them together for 15 minutes to disperse them evenly. This solution is called solution B.

[0029] Mix solutions A and B and transfer them to a 100ml hydrothermal reactor. React at 160℃ for 12 hours.

[0030] After the reactor cooled, the mixture was filtered using a vacuum filter, washed three times each with DMF and ethanol, and then dried at 80°C to obtain the light green Ni-MOF material.

[0031] 150 mg of Ni-MOF and 450 mg of NaH2PO2·H2O were placed downstream and upstream of a ceramic boat, respectively. The temperature was increased to 350 °C at a rate of 25 °C / min and held for 2 h to obtain a P-Ni@C catalyst, denoted as S1.

[0032] Example 2

[0033] Weigh 2.28g Ni(NO3)2·6H2O and 20ml DMF separately and mix them together. Sonicate them together for 15min until a clear solution A is formed.

[0034] Weigh out 0.44g of terephthalic acid and 20ml of DMF and mix them together. Sonicate them together for 15 minutes to disperse them evenly. This solution is called solution B.

[0035] Mix solutions A and B and transfer them to a 100ml hydrothermal reactor. React at 160℃ for 12 hours.

[0036] After the reactor cooled, the mixture was filtered using a vacuum filter, washed three times each with DMF and ethanol, and then dried at 80°C to obtain the light green Ni-MOF material.

[0037] 150 mg of Ni-MOF and 450 mg of NaH2PO2·H2O were placed downstream and upstream of a ceramic boat, respectively. The temperature was increased to 350 °C at a rate of 25 °C / min and held for 2 h to obtain the P-Ni@C catalyst, denoted as S2.

[0038] Example 3

[0039] Weigh out 1.14g Ni(NO3)2·6H2O and 20ml DMF respectively and mix them together. Sonicate them together for 15min until a clear solution A is formed.

[0040] Weigh out 0.88g of terephthalic acid and 20ml of DMF and mix them together. Sonicate them together for 15min to disperse them evenly. This solution is called solution B.

[0041] Mix solutions A and B and transfer them to a 100ml hydrothermal reactor. React at 160℃ for 12 hours.

[0042] After the reactor cooled, the mixture was filtered using a vacuum filter, washed three times each with DMF and ethanol, and then dried at 80°C to obtain the light green Ni-MOF material.

[0043] 150 mg of Ni-MOF and 450 mg of NaH2PO2·H2O were placed downstream and upstream of a ceramic boat, respectively. The temperature was increased to 350 °C at a rate of 25 °C / min and held for 2 h to obtain the P-Ni@C catalyst, denoted as S3.

[0044] Example 4

[0045] Weigh out 1.14g Ni(NO3)2·6H2O and 20ml DMF respectively and mix them together. Sonicate them together for 15min until a clear solution A is formed.

[0046] Weigh out 0.44g of terephthalic acid and 20ml of DMF and mix them together. Sonicate them together for 15 minutes to disperse them evenly. This solution is called solution B.

[0047] Mix solutions A and B and transfer them to a 100ml hydrothermal reactor. React at 140℃ for 12 hours.

[0048] After the reactor cooled, the mixture was filtered using a vacuum filter, washed three times each with DMF and ethanol, and then dried at 80°C to obtain the light green Ni-MOF material.

[0049] 150 mg of Ni-MOF and 450 mg of NaH2PO2·H2O were placed downstream and upstream of a ceramic boat, respectively. The temperature was increased to 350 °C at a rate of 25 °C / min and held for 2 h to obtain the P-Ni@C catalyst, denoted as S4.

[0050] Example 5

[0051] Weigh out 1.14g Ni(NO3)2·6H2O and 20ml DMF respectively and mix them together. Sonicate them together for 15min until a clear solution A is formed.

[0052] Weigh out 0.44g of terephthalic acid and 20ml of DMF and mix them together. Sonicate them together for 15 minutes to disperse them evenly. This solution is called solution B.

[0053] Mix solutions A and B and transfer them to a 100ml hydrothermal reactor. React at 180℃ for 12 hours.

[0054] After the reactor cooled, the mixture was filtered using a vacuum filter, washed three times each with DMF and ethanol, and then dried at 80°C to obtain the light green Ni-MOF material.

[0055] 150 mg of Ni-MOF and 450 mg of NaH2PO2·H2O were placed downstream and upstream of a ceramic boat, respectively. The temperature was increased to 350 °C at a rate of 25 °C / min and held for 2 h to obtain the P-Ni@C catalyst, denoted as S5.

[0056] Example 6

[0057] Weigh out 1.14g Ni(NO3)2·6H2O and 20ml DMF respectively and mix them together. Sonicate them together for 15min until a clear solution A is formed.

[0058] Weigh out 0.44g of terephthalic acid and 20ml of DMF and mix them together. Sonicate them together for 15 minutes to disperse them evenly. This solution is called solution B.

[0059] Mix solutions A and B and transfer them to a 100ml hydrothermal reactor. React at 160℃ for 10 hours.

[0060] After the reactor cooled, the mixture was filtered using a vacuum filter, washed three times each with DMF and ethanol, and then dried at 80°C to obtain the light green Ni-MOF material.

[0061] 150 mg of Ni-MOF and 450 mg of NaH2PO2·H2O were placed downstream and upstream of a ceramic boat, respectively. The temperature was increased to 350 °C at a rate of 25 °C / min and held for 2 h to obtain the P-Ni@C catalyst, denoted as S6.

[0062] Example 7

[0063] Weigh out 1.14g Ni(NO3)2·6H2O and 20ml DMF respectively and mix them together. Sonicate them together for 15min until a clear solution A is formed.

[0064] Weigh out 0.44g of terephthalic acid and 20ml of DMF and mix them together. Sonicate them together for 15 minutes to disperse them evenly. This solution is called solution B.

[0065] Mix solutions A and B and transfer them to a 100ml hydrothermal reactor. React at 160℃ for 14 hours.

[0066] After the reactor cooled, the mixture was filtered using a vacuum filter, washed three times each with DMF and ethanol, and then dried at 80°C to obtain the light green Ni-MOF material.

[0067] 150 mg of Ni-MOF and 450 mg of NaH2PO2·H2O were placed downstream and upstream of a ceramic boat, respectively. The temperature was increased to 350 °C at a rate of 25 °C / min and held for 2 h to obtain a P-Ni@C catalyst, denoted as S7.

[0068] Example 8

[0069] Weigh out 1.14g Ni(NO3)2·6H2O and 20ml DMF respectively and mix them together. Sonicate them together for 15min until a clear solution A is formed.

[0070] Weigh out 0.44g of terephthalic acid and 20ml of DMF and mix them together. Sonicate them together for 15 minutes to disperse them evenly. This solution is called solution B.

[0071] Mix solutions A and B and transfer them to a 100ml hydrothermal reactor. React at 160℃ for 12 hours.

[0072] After the reactor cooled, the mixture was filtered using a vacuum filter, washed three times each with DMF and ethanol, and then dried at 80°C to obtain the light green Ni-MOF material.

[0073] 150 mg of Ni-MOF and 150 mg of NaH2PO2·H2O were placed downstream and upstream of a ceramic boat, respectively, and the temperature was increased to 350 °C at a rate of 25 °C / min and held for 2 h to obtain a P-Ni@C catalyst, denoted as S8.

[0074] Example 9

[0075] Weigh out 1.14g Ni(NO3)2·6H2O and 20ml DMF respectively and mix them together. Sonicate them together for 15min until a clear solution A is formed.

[0076] Weigh out 0.44g of terephthalic acid and 20ml of DMF and mix them together. Sonicate them together for 15 minutes to disperse them evenly. This solution is called solution B.

[0077] Mix solutions A and B and transfer them to a 100ml hydrothermal reactor. React at 160℃ for 12 hours.

[0078] After the reactor cooled, the mixture was filtered using a vacuum filter, washed three times each with DMF and ethanol, and then dried at 80°C to obtain the light green Ni-MOF material.

[0079] 150 mg of Ni-MOF and 750 mg of NaH2PO2·H2O were placed downstream and upstream of a ceramic boat, respectively. The temperature was increased to 350 °C at a rate of 25 °C / min and held for 2 h to obtain a P-Ni@C catalyst, denoted as S9.

[0080] Example 10

[0081] Weigh out 1.14g Ni(NO3)2·6H2O and 20ml DMF respectively and mix them together. Sonicate them together for 15min until a clear solution A is formed.

[0082] Weigh out 0.44g of terephthalic acid and 20ml of DMF and mix them together. Sonicate them together for 15 minutes to disperse them evenly. This solution is called solution B.

[0083] Mix solutions A and B and transfer them to a 100ml hydrothermal reactor. React at 160℃ for 12 hours.

[0084] After the reactor cooled, the mixture was filtered using a vacuum filter, washed three times each with DMF and ethanol, and then dried at 80°C to obtain the light green Ni-MOF material.

[0085] 150 mg of Ni-MOF and 450 mg of NaH2PO2·H2O were placed downstream and upstream of a ceramic boat, respectively. The temperature was increased to 250 °C at a rate of 25 °C / min and held for 2 h to obtain a P-Ni@C catalyst, denoted as S10.

[0086] Example 11

[0087] Weigh out 1.14g Ni(NO3)2·6H2O and 20ml DMF respectively and mix them together. Sonicate them together for 15min until a clear solution A is formed.

[0088] Weigh out 0.44g of terephthalic acid and 20ml of DMF and mix them together. Sonicate them together for 15 minutes to disperse them evenly. This solution is called solution B.

[0089] Mix solutions A and B and transfer them to a 100ml hydrothermal reactor. React at 160℃ for 12 hours.

[0090] After the reactor cooled, the mixture was filtered using a vacuum filter, washed three times each with DMF and ethanol, and then dried at 80°C to obtain the light green Ni-MOF material.

[0091] 150 mg of Ni-MOF and 450 mg of NaH2PO2·H2O were placed downstream and upstream of a ceramic boat, respectively. The temperature was increased to 450 °C at a rate of 25 °C / min and held for 2 h to obtain the P-Ni@C catalyst, denoted as S11.

[0092] Example 12

[0093] Weigh out 1.14g Ni(NO3)2·6H2O and 20ml DMF respectively and mix them together. Sonicate them together for 15min until a clear solution A is formed.

[0094] Weigh out 0.44g of terephthalic acid and 20ml of DMF and mix them together. Sonicate them together for 15 minutes to disperse them evenly. This solution is called solution B.

[0095] Mix solutions A and B and transfer them to a 100ml hydrothermal reactor. React at 160℃ for 12 hours.

[0096] After the reactor cooled, the mixture was filtered using a vacuum filter, washed three times each with DMF and ethanol, and then dried at 80°C to obtain the light green Ni-MOF material.

[0097] 150 mg of Ni-MOF and 450 mg of NaH2PO2·H2O were placed downstream and upstream of a ceramic boat, respectively. The temperature was increased to 350 °C at a rate of 25 °C / min and held for 1 h to obtain a P-Ni@C catalyst, denoted as S12.

[0098] Example 13

[0099] Weigh out 1.14g Ni(NO3)2·6H2O and 20ml DMF respectively and mix them together. Sonicate them together for 15min until a clear solution A is formed.

[0100] Weigh out 0.44g of terephthalic acid and 20ml of DMF and mix them together. Sonicate them together for 15 minutes to disperse them evenly. This solution is called solution B.

[0101] Mix solutions A and B and transfer them to a 100ml hydrothermal reactor. React at 160℃ for 12 hours.

[0102] After the reactor cooled, the mixture was filtered using a vacuum filter, washed three times each with DMF and ethanol, and then dried at 80°C to obtain the light green Ni-MOF material.

[0103] 150 mg of Ni-MOF and 450 mg of NaH2PO2·H2O were placed downstream and upstream of a ceramic boat, respectively. The temperature was increased to 350 °C at a rate of 25 °C / min and held for 3 h to obtain the P-Ni@C catalyst, denoted as S13.

[0104] Comparative Example

[0105] Weigh out 1.14g Ni(NO3)2·6H2O and 20ml DMF respectively and mix them together. Sonicate them together for 15min until a clear solution A is formed.

[0106] Weigh out 0.44g of terephthalic acid and 20ml of DMF and mix them together. Sonicate them together for 15 minutes to disperse them evenly. This solution is called solution B.

[0107] Mix solutions A and B and transfer them to a 100ml hydrothermal reactor. React at 160℃ for 12 hours.

[0108] After the reactor cooled, the mixture was filtered using a vacuum filter, washed three times each with DMF and ethanol, and then dried at 80°C to obtain the light green Ni-MOF material.

[0109] 150 mg of Ni-MOF was placed in a tube furnace and heated to 350 °C at a rate of 25 °C / min, and held for 2 h to obtain Ni@C.

[0110] 150 mg of Ni@C and 450 mg of NaH2PO2·H2O were placed downstream and upstream of a ceramic boat, respectively, and the temperature was increased to 350 °C at a rate of 25 °C / min and held for 2 h to obtain the P / Ni@C catalyst.

[0111] Figure 1 and Figure 2SEM images of the P / Ni@C catalysts prepared in S1 and the comparative example are shown. As can be seen from the images, both belong to a carbon film encapsulation structure. In addition, the P-Ni@C catalyst prepared by the one-step carbonization and phosphating method has a larger pore size and the Ni nanoparticles have higher dispersibility.

[0112] Figure 3 The figure compares the catalytic activities of S1 and P / Ni@C catalysts in hydrothermal liquefaction experiments. As shown in the figure, there is no significant difference in the catalytic performance of P-Ni@C and P / Ni@C catalysts for guaiacol; however, the P-Ni@C catalyst significantly reduces the formation of benzene compounds and improves the selectivity for phenolic compounds.

[0113] Figure 4 The figure shows the results of the S1 cycle test. As can be seen from the figure, after the catalyst is recycled 5 times, the conversion rate of the feedstock and the yield of phenolic compounds basically did not decrease, which indicates that the P-Ni@C catalyst has good stability.

[0114] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application. The scope of this application is defined by the appended claims and their equivalents, all of which should be included within the protection scope of this application.

Claims

1. A method for preparing a P-Ni@C catalyst with a carbon phosphate film encapsulation structure, characterized in that, The steps are as follows: S1: Nickel salt and terephthalic acid are hydrothermally reacted in N,N-dimethylformamide. The product after the reaction is filtered, washed and dried to obtain the intermediate product. S2: NaH2PO2·H2O and intermediate products are placed upstream and downstream of a ceramic boat for one-step carbonization and phosphating to obtain a P-Ni@C catalyst.

2. The preparation method of the P-Ni@C catalyst with phosphide film encapsulation structure according to claim 1, characterized in that, The mass ratio of nickel salt to terephthalic acid in S1 is 1:0.1-10.

3. The method for preparing the P-Ni@C catalyst with a phosphide-coated film structure according to claim 1, characterized in that, The hydrothermal reaction in S1 takes place at a temperature of 140-180℃ for 8-16 hours.

4. The method for preparing the P-Ni@C catalyst with a phosphide-coated film structure according to claim 1, characterized in that, The mass ratio of intermediate product to NaH2PO2·H2O in S2 is 1:2-4.

5. The method for preparing the P-Ni@C catalyst with a phosphide-coated film structure according to claim 1, characterized in that, The temperature for one-step carbonization and phosphating in S2 is 250-450℃, and the holding time is 1-3h.

6. A P-Ni@C catalyst with a carbon phosphate film encapsulation structure, characterized in that, It is prepared by the preparation method according to any one of claims 1-5.

7. The application of the P-Ni@C catalyst with phosphide film encapsulation structure as described in claim 6 in the hydrothermal liquefaction of biomass.

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